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1.  Molecular Imaging of Urogenital Diseases 
Seminars in nuclear medicine  2014;44(2):93-109.
There is an expanding and exciting repertoire of PET imaging radiotracers for urogenital diseases, particularly in prostate cancer, renal cell cancer, and renal function. Prostate cancer is the most commonly diagnosed cancer in men. With growing therapeutics options for the treatment of metastatic and advanced prostate cancer, improved functional imaging of prostate cancer beyond the limitations of conventional computed tomography (CT) and bone scan (BS) is becoming increasingly important for both clinical management and drug development. PET radiotracers beyond 18F-Fluorodeoxyglucose (FDG) for prostate cancer include 18F-Sodium Fluoride, 11C-Choline and 18F-Fluorocholine and 11C-Acetate. Other emerging and promising PET radiotracers include a synthetic L-leucine amino acid analog (anti-18F-FACBC), dihydrotestosterone analog (18F-FDHT) and prostate specific membrane antigen (PSMA) based PET radiotracers (ex. 18F-DCFBC, 89Zr-DFO-J591, 68Ga(HBED-CC)). Larger prospective and comparison trials of these PET radiotracers are needed to establish the role of PET/CT in prostate cancer. Renal cell cancer imaging with FDG PET/CT although available can be limited, especially for detection of the primary tumor. Improved renal cell cancer detection with carbonic anhydrase IX (CAIX) based antibody (124I-girentuximab) and radioimmunotherapy targeting with 177Lu-cG250 appear promising. Evaluation of renal injury by imaging renal perfusion and function with novel PET radiotracers include p-18F-fluorohippurate (18F-PFH) and hippurate m-cyano-p-18F-fluorohippurate (18F-CNPFH) and Rubidium-82 chloride (typically used for myocardial perfusion imaging). Renal receptor imaging of the renal renin angiotensin system with a variety of selective PET radioligands are also becoming available for clinical translation.
PMCID: PMC3912464  PMID: 24484747
2.  Androgen Receptor as a Driver of Therapeutic Resistance in Advanced Prostate Cancer 
The role of the androgen receptor (AR) signaling axis in the progression of prostate cancer is a cornerstone to our understanding of the molecular mechanisms causing castration-resistant prostate cancer (CRPC). Resistance of advanced prostate cancer to available treatment options makes it a clinical challenge that results in approximately 30,000 deaths of American men every year. Since the historic discovery by Dr. Huggins more than 70 years ago, androgen deprivation therapy (ADT) has been the principal treatment for advanced prostate cancer. Initially, ADT induces apoptosis of androgen-dependent prostate cancer epithelial cells and regression of androgen-dependent tumors. However, the majority of patients with advanced prostate cancer progress and become refractory to ADT due to emergence of androgen-independent prostate cancer cells driven by aberrant AR activation. Microtubule-targeting agents such as taxanes, docetaxel and paclitaxel, have enjoyed success in the treatment of metastatic prostate cancer; although new, recently designed mitosis-specific agents, such as the polo-kinase and kinesin-inhibitors, have yielded clinically disappointing results. Docetaxel, as a first-line chemotherapy, improves prostate cancer patient survival by months, but tumor resistance to these therapeutic agents inevitably develops. On a molecular level, progression to CRPC is characterized by aberrant AR expression, de novo intraprostatic androgen production, and cross talk with other oncogenic pathways. Emerging evidence suggests that reactivation of epithelial-mesenchymal-transition (EMT) processes may facilitate the development of not only prostate cancer but also prostate cancer metastases. EMT is characterized by gain of mesenchymal characteristics and invasiveness accompanied by loss of cell polarity, with an increasing number of studies focusing on the direct involvement of androgen-AR signaling axis in EMT, tumor progression, and therapeutic resistance. In this article, we discuss the current knowledge of mechanisms via which the AR signaling drives therapeutic resistance in prostate cancer metastatic progression and the novel therapeutic interventions targeting AR in CRPC.
PMCID: PMC4062951  PMID: 24948871
Androgen receptor; taxanes; prostate cancer; therapeutic resistance; tumor progression; castration resistance; epithelial-mesenchymal transition.
3.  Progression of metastatic castrate-resistant prostate cancer: impact of therapeutic intervention in the post-docetaxel space 
Despite the proven success of hormonal therapy for prostate cancer using chemical or surgical castration, most patients eventually will progress to a phase of the disease that is metastatic and shows resistance to further hormonal manipulation. This has been termed metastatic castrate-resistant prostate cancer (mCRPC). Despite this designation, however, there is evidence that androgen receptor (AR)-mediated signaling and gene expression can persist in mCRPC, even in the face of castrate levels of androgen. This may be due in part to the upregulation of enzymes involved in androgen synthesis, the overexpression of AR, or the emergence of mutant ARs with promiscuous recognition of various steroidal ligands. The therapeutic options were limited and palliative in nature until trials in 2004 demonstrated that docetaxel chemotherapy could significantly improve survival. These results established first-line docetaxel as the standard of care for mCRPC. After resistance to further docetaxel therapy develops, treatment options were once again limited. Recently reported results from phase 3 trials have shown that additional therapy with the novel taxane cabazitaxel (with prednisone), or treatment with the antiandrogen abiraterone (with prednisone) could improve survival for patients with mCRPC following docetaxel therapy. Compared with mitoxantrone/prednisone, cabazitaxel/prednisone significantly improved overall survival, with a 30% reduction in rate of death, in patients with progression of mCRPC after docetaxel therapy in the TROPIC trial. Similarly, abiraterone acetate (an inhibitor of androgen biosynthesis) plus prednisone significantly decreased the rate of death by 35% compared with placebo plus prednisone in mCRPC patients progressing after prior docetaxel therapy in the COU-AA-301 trial. Results of these trials have thus established two additional treatment options for mCRPC patients in the "post-docetaxel space." In view of the continued AR-mediated signaling on mCRPC, results from additional phase 3 studies with novel antiandrogens which are directed at inhibition of the AR (e.g., MDV3100), as well as other agents, are awaited with interest and may further expand the treatment choices for this difficult-to-manage population of patients.
PMCID: PMC3102641  PMID: 21513551
4.  PET/CT imaging and radioimmunotherapy of prostate cancer 
Seminars in Nuclear Medicine  2011;41(1):29-44.
Prostate cancer is a common cancer in men and continues to be a major health problem. Imaging plays an important role in the clinical management of patients with prostate cancer. An important goal for prostate cancer imaging is more accurate disease characterization through the synthesis of anatomic, functional, and molecular imaging information. Positron emission tomography (PET)/computed tomography (CT) in oncology is emerging as an important imaging tool. The most common radiotracer for PET/CT in oncology, 18F- fluorodeoxyglucose (FDG), is not very useful in prostate cancer. However, in recent years other PET tracers have improved the accuracy of PET/CT imaging of prostate cancer. Among these, choline, labelled with 18F or 11C, 11C-acetate and 18F- fluoride have demonstrated promising results, and other new radiopharmaceuticals are currently under development and evaluation in pre-clinical and clinical studies. Large prospective clinical PET/CT trials are needed to establish the role of PET/CT in prostate cancer patients. Because there are only limited available therapeutic options for advanced metastatic prostate cancer, there is an urgent need for the development of more effective treatment modalities that could improve outcome. Prostate cancer represents an attractive target for radioimmunotherapy (RIT) for several reasons, including pattern of metastatic spread (lymph nodes and bone marrow, sites with good access to circulating antibodies), and small volume disease (ideal for antigen access and antibody delivery). Furthermore, prostate cancer is also radiation sensitive. Prostate-specific membrane antigen (PSMA) is expressed by virtually all prostate cancers, and represents an attractive target for RIT. Anti PSMA RIT demonstrates antitumor activity and is well tolerated. Clinical trials are underway to further improve upon treatment efficacy and patient selection. This review focuses on the recent advances of clinical PET/CT imaging and RIT of prostate cancer.
PMCID: PMC3392994  PMID: 21111858
positron-emission tomography; PET; PET/CT; radioimmunotherapy; RIT; prostate cancer
5.  Unmet Needs in the Prediction and Detection of Metastases in Prostate Cancer 
The Oncologist  2013;18(5):549-557.
Despite advances in therapy options, few guidelines or reviews address the optimal timing or methodology for the radiographic detection of metastatic disease in patients with advanced prostate cancer. This review discusses the current status of predicting the presence of metastatic disease, with a particular emphasis on the detection of the M0 to M1 transition, and reviews current data on newer imaging technologies that are changing the way metastases are detected.
The therapeutic landscape for the treatment of advanced prostate cancer is rapidly evolving, especially for those patients with metastatic castration-resistant prostate cancer (CPRC). Despite advances in therapy options, the diagnostic landscape has remained relatively static, with few guidelines or reviews addressing the optimal timing or methodology for the radiographic detection of metastatic disease. Given recent reports indicating a substantial proportion of patients with CRPC thought to be nonmetastatic (M0) are in fact metastatic (M1), there is now a clear opportunity and need for improvement in detection practices. Herein, we discuss the current status of predicting the presence of metastatic disease, with a particular emphasis on the detection of the M0 to M1 transition. In addition, we review current data on newer imaging technologies that are changing the way metastases are detected. Whether earlier detection of metastatic disease will ultimately improve patient outcomes is unknown, but given that the therapeutic options for those with metastatic and nonmetastatic CPRC vary, there are considerable implications of how and when metastases are detected.
PMCID: PMC3662846  PMID: 23650019
Imaging; Lymph nodes; Magnetic resonance imaging; Neoplasm metastasis; Prostatic neoplasms; Radionuclide imaging
6.  Current state of prostate cancer treatment in Jamaica 
ecancermedicalscience  2014;8:456.
Prostate cancer is the commonest cancer in Jamaica as well as the leading cause of cancer-related deaths. One report suggested that Jamaica has the highest incidence rate of prostate cancer in the world, with an age-standardised rate of 304/100,000 per year. The Caribbean region is reported to have the highest mortality rate of prostate cancer worldwide. Prostate cancer accounts for a large portion of the clinical practice for health-care practitioners in Jamaica. The Jamaica Urological Society is a professional body comprising 19 urologists in Jamaica who provide most of the care for men with prostate cancer in collaboration with medical oncologists, radiation oncologists, and a palliative care physician. The health-care system is structured in two tiers in Jamaica: public and private. The urologist-to-patient ratio is high, and this limits adequate urological care. Screening for prostate cancer is not a national policy in Jamaica. However, the Jamaica Urological Society and the Jamaica Cancer Society work synergistically to promote screening as well as to provide patient education for prostate cancer. Adequate treatment for localised prostate cancer is available in Jamaica in the forms of active surveillance, nerve-sparing radical retropubic prostatectomy, external beam radiation, and brachytherapy. However, there is a geographic maldistribution of centres that provide prostate cancer treatment, which leads to treatment delays. Also, there is difficulty in affording some treatment options in the private health-care sectors. Androgen deprivation therapy is available for treatment of locally advanced and metastatic prostate cancer and is subsidised through a programme called the National Health Fund. Second-line hormonal agents and chemotherapeutic agents are available but are costly to most of the population. The infrastructure for treatment of prostate cancer in Jamaica is good, but it requires additional technological advances as well as additional specialist services.
PMCID: PMC4154943  PMID: 25228912
prostate cancer; Jamaica; outcomes; radical prostatectomy; radiation
7.  Immune Response to Sipuleucel-T in Prostate Cancer 
Cancers  2012;4(2):420-441.
Historically, chemotherapy has remained the most commonly utilized therapy in patients with metastatic cancers. In prostate cancer, chemotherapy has been reserved for patients whose metastatic disease becomes resistant to first line castration or androgen deprivation. While chemotherapy palliates, decreases serum prostate specific antigen and improves survival, it is associated with significant side effects and is only suitable for approximately 60% of patients with castrate-resistant prostate cancer. On that basis, exploration of other therapeutic options such as active secondary hormone therapy, bone targeted treatments and immunotherapy are important. Until recently, immunotherapy has had no role in the treatment of solid malignancies aside from renal cancer and melanoma. The FDA-approved autologous cellular immunotherapy sipuleucel-T has demonstrated efficacy in improving overall survival in patients with metastatic castrate-resistant prostate cancer in randomized clinical trials. The proposed mechanism of action is reliant on activating the patients’ own antigen presenting cells (APCs) to prostatic acid phosphatase (PAP) fused with granulocyte-macrophage colony stimulating factor (GM-CSF) and subsequent triggered T-cell response to PAP on the surface of prostate cancer cells in the patients body. Despite significant prolongation of survival in Phase III trials, the challenge to health care providers remains the dissociation between objective changes in serum PSA or on imaging studies after sipleucel-T and survival benefit. On that basis there is an unmet need for markers of outcome and a quest to identify immunologic or clinical surrogates to fill this role. This review focuses on the impact of sipuleucel-T on the immune system, the T and B cells, and their responses to relevant antigens and prostate cancer. Other therapeutic modalities such as chemotherapy, corticosteroids and GM-CSF and host factors can also affect immune response. The optimal timing for immunotherapy, patient selection and best sequencing with other prostate cancer therapies remain to be determined. A better understanding of immune response may help address these issues.
PMCID: PMC3712699  PMID: 24213318
castrate resistant prostate cancer; immunotherapy; biomarkers; sipuleucel-T; immune response
8.  Current Treatment Strategies for Castration-Resistant Prostate Cancer 
Korean Journal of Urology  2011;52(3):157-165.
Prostate cancer is the most common cancer in men in United States and the fifth most common cancer in men in Korea. Although the majority of patients with metastatic prostate cancer initially respond to androgen deprivation therapy, almost all patients will eventually progress to develop castration-resistant prostate cancer (CRPC). Treatment options for CRPC remain limited. Prostate cancer was considered unresponsive to chemotherapy until the mid-1990s, when mitoxantrone combined with prednisone was shown to play a role in the palliative treatment of patients with CRPC. In 2004, two large randomized clinical trials demonstrated for the first time a small but significant survival advantage of docetaxel-based chemotherapy compared with mitoxantrone in patients with metastatic CRPC. Recently, cabazitaxel was shown to improve survival in patients with metastatic CRPC who progressed after docetaxel-based chemotherapy. Sipuleucel-T was also demonstrated to improve overall survival in patients with asymptomatic or minimally symptomatic metastatic CRPC. Along with mitoxantrone and docetaxel, cabazitaxel and sipuleucel-T are now approved for use in metastatic CRPC by the US Food and Drug Administration. There have been multiple early-phase clinical trials of various agents for the treatment of CRPC, and some are in phase III development. This review focuses on the key clinical trials of various treatment options of CRPC currently in use and under investigation.
PMCID: PMC3065126  PMID: 21461278
Drug therapy; Immunotherapy; Molecular targeted therapy; Prostatic neoplasms; Survival
9.  Modulating metastasis by a lymphangiogenic switch in prostate cancer 
Prostate cancer dissemination is difficult to detect in the clinic, and few treatment options exist for patients with advanced-stage disease. Our aim was to investigate the role of tumor lymphangiogenesis during metastasis. Further, we implemented a noninvasive molecular imaging technique to facilitate the assessment of the metastatic process. The metastatic potentials of several human prostate cancer xenograft models, LAPC-4, LAPC-9, PC3 and CWR22Rv-1 were compared. The cells were labeled with luciferase, a bioluminescence imaging reporter gene, to enable optical imaging. After tumor implantation the animals were examined weekly during several months for the appearance of metastases. Metastatic lesions were confirmed by immunohistochemistry. Additionally, the angiogenic and lymphangiogenic profiles of the tumors were characterized. To confirm the role of lymphangiogenesis in mediating metastasis, the low-metastatic LAPC-9 tumor cells were engineered to overexpress VEGF-C, and the development of metastases was evaluated. Our results show CWR22Rv-1 and PC3 tumor cell lines to be more metastatic than LAPC-4, which in turn disseminates more readily than LAPC-9. The difference in metastatic potential correlated with the endogenous production levels of lymphangiogenic growth factor VEGF-C and the presence of tumor lymphatics. In agreement, induced overexpression of VEGF-C in LAPC-9 enhanced tumor lymphangiogenesis leading to the development of metastatic lesions. Taken together, our studies, based on a molecular imaging approach for semiquantitative detection of micrometastases, point to an important role of tumor lymphatics in the metastatic process of human prostate cancer. In particular, VEGF-C seems to play a key role in prostate cancer metastasis.
PMCID: PMC2838420  PMID: 17583576
lymphatics; vascular endothelial growth factor; lung; luciferase; lymph node
10.  T40214/PEI Complex, a Potent Therapeutics for Prostate Cancer that Targets STAT3 Signaling 
The Prostate  2008;68(13):1430-1442.
Prostate cancer is the most common cancer among men in American and the second leading cause of cancer death. The treatment options employed for patients with advanced and metastatic prostate cancer are limited. As a critical mediator of oncogenic signaling, STAT3 is active in 82% of patients with prostate cancer. STAT3 has become a very important molecular target for prostate cancer therapy since it upregulates the oncogenes encoding apoptosis inhibitors, cell-cycle regulators, and inducers of angiogenesis. However, no anti-tumor drug whose primary mode of action is to target STAT3 has yet reached the clinic. To this end, we have laid the initial groundwork to develop the STAT3-inhibiting G-quartet oligodeoxynucleotide (GQ-ODN), T40214, for treatment of prostate cancers.
We employed in vitro and in vivo assays, including western blots, EMSA, cell cycle analysis, TUNEL and xenograft models, to determine the drug efficacy and mechanism of T40214/PEI complex.
The results demonstrated that (i) T40214 significantly inhibited STAT3 activation and induced apoptosis in both androgen-dependent and androgen-independent prostate cancer cells; (ii) T40214 delivered by PEI (ployethylenimine) significantly suppressed prostate tumor growth in tumor-bearning nude mice due to that T40214 inhibited STAT3 activation and then greatly promoted apoptosis, reduced angiogenesis and cell proliferation in prostate tumors.
Our studies suggested that STAT3 is a critical oncogenic signal, which strongly influences the progression of prostate cancers and that T40214/PEI complex is a promising candidate for treatment of patients with prostate tumors and represents a novel strategy for prostate cancer therapy.
PMCID: PMC2574665  PMID: 18615483
11.  The Role of Cryosurgery of the Prostate for Nonsurgical Candidates 
This report describes the experience of using cryosurgery as primary total gland therapy, salvage therapy after radiation failure, and for focal ablation for localized prostate cancer.
Technological advancements have reduced the morbidity associated with cryosurgery, leading to an increased interest in this modality for the treatment of organ-confined prostate cancer. In this study, we critically examine the current role of cryoablation of the prostate to better understand how to counsel patients regarding this treatment option.
A database was compiled over a 3-year period (2008–2011) of 30 patients who underwent cryoablation for organ-confined prostate cancer. Indications for cryosurgery included primary treatment, focal treatment (institutional review board–approved prospective study), and salvage cryotherapy for radiation failure. The primary outcomes were biochemical response via prostate-specific antigen (PSA) measurement and morbidity associated with cryoablation. Cryotherapy failure was defined as an increasing postcryotherapy PSA level ≥ 2 ng/mL above the post-treatment nadir, a positive prostate biopsy, or radiographic evidence of metastatic disease.
Of the 30 patients who underwent cryoablation from 2008 to 2011, 26 patients had complete follow-up data for analysis. Of these patients, 17 (65.38%) had total gland cryotherapy, 5 (19.23%) had salvage cryotherapy for radiation failure, and 4 (15.38%) had focal cryotherapy. The mean patient age was 68 years (54–89); median preoperative PSA was 5.5 ng/mL (1.7–15.9); median prostate volume was 35 mL (15–54); mean Gleason score was 7; and the median PSA at study conclusion was 0.7 (0.02–3.4) ng/mL. Of the 17 patients who had total prostate cryotherapy, 11 (64.7%) had significant factors precluding primary treatment by a surgical and/or radiation approach, including neurological disorders (2), morbid obesity (1), rectal cancer treated with radiation (1), kidney/pancreas transplant (2), ileoanal pouch secondary to inflammatory bowel disease (IBD) (1), renal failure (1), and age (3).There were no intra- or postoperative complications. After a median follow-up of 18 months (1–40), none of the patients with multiple comorbidities had biochemical failures. Two patients from the salvage group experienced treatment failure requiring androgen deprivation therapy.
This critical analysis of a single-surgeon experience at a large academic prostate cancer program revealed that the contemporary role of cryosurgery is, in select patients with comorbidities, preventing surgical and/or radiation therapy. Additionally, cryosurgery has a role in treating radiation failures. Further studies are necessary to investigate focal cryotherapy as an option for primary treatment, but our preliminary results are promising, without any biochemical failures in our focal therapy cohort.
PMCID: PMC3771762  PMID: 24018080
Prostate cancer; Cryotherapy; Comorbidities
12.  Expression of prostate specific antigen in male breast cancer 
Journal of Clinical Pathology  2005;58(1):69-71.
Male breast cancer is uncommon, accounting for less than 1% of all breast cancers. Carcinoma metastatic to the male breast is also unusual, with metastatic prostatic carcinoma being among the most common primary sites from which such tumours derive. Metastatic prostatic cancer and primary breast cancer may be histologically indistinguishable without immunohistochemistry because both often infiltrate with a cribriform architecture. Distinguishing between primary and metastatic disease within the breast is important because the treatment options for each are radically different. Following a case in which metastatic prostatic disease was initially wrongly diagnosed as primary breast cancer, a small series of male breast cancers was examined for expression of prostate specific antigen (PSA) and prostatic acid phosphatase to assess the usefulness of these markers in making this distinction. Focal expression of PSA was found in one of 11 cases of male breast cancer. These results indicate that PSA should be used with caution in this context.
PMCID: PMC1770557  PMID: 15623486
breast cancer; male; prostate specific antigen
13.  Prostate Cancer Predisposition Loci and Risk of Metastatic Disease and Prostate Cancer Recurrence 
Genome-wide association studies (GWAS) have identified multiple novel prostate cancer predisposition loci. Whether these common genetic variants are associated with incident metastatic prostate cancer or with recurrence after surgical treatment for clinically localized prostate cancer is uncertain.
Twelve SNPs were selected for study in relation to prostate metastatic cancer and recurrence, based on their genome-wide association with prostate cancer in the Cancer Genetic Markers of Susceptibility (CGEMS) (1, 2). To assess risk for metastatic disease, we compared genotypes for the 12 SNPs by logistic regression of 470 incident metastatic prostate cancer cases and 1945 controls in 3 case-control studies. To assess the relationship of these SNPs to risk for prostate cancer recurrence, we used Cox regression in a cohort of 1412 men treated for localized prostate cancer, including 328 recurrences, and used logistic regression in a case-case study, comparing 450 recurrent versus 450 nonrecurrent prostate cancer cases. Study-specific RRs for risk of metastatic disease and recurrence were summarized using meta-analysis, with inverse variance weights.
MSMB rs10993994 (per variant allele summary RR=1.24, 95% CI=1.05-1.48), 8q24 rs4242382 (RR=1.40, 95% CI=1.13-1.75) and 8q24 rs6983267 (RR=0.67, 95% CI=0.50-0.89) were associated with risk for metastatic prostate cancer. None of the 12 SNPs was associated with prostate cancer recurrence.
SNPs in MSMB and 8q24 which predispose to prostate cancer overall are associated with risk for metastatic prostate cancer, the most lethal form of this disease. SNPs predictive of prostate cancer recurrence were not identified, among the predisposition SNPs. GWAS specific to these two phenotypes may identify additional phenotype-specific genetic determinants.
PMCID: PMC3059497  PMID: 21343373
14.  Metastatic castrate-resistant prostate cancer with a late, complete and durable response to docetaxel chemotherapy: a case report 
Although treatment options for men with metastatic castrate-resistant prostate cancer have improved in recent years, the outlook for patients remains poor, with overall survival in the region of 2 years. Response rates with chemotherapy are modest and disease progression is usually observed within months of stopping treatment.
Case presentation
We present a case of a 72-year-old White man of British origin with metastatic castrate-resistant prostate cancer with bulky lymphadenopathy and a serum prostate-specific antigen of 295μg/L. He received treatment with docetaxel chemotherapy plus prednisolone, but received just 3 cycles before treatment was stopped due to toxicity and lack of response (prostate-specific antigen was 276μg/L 4 weeks after the last dose and there was a confirmed stable appearance on computed tomography scan). Unexpectedly, at follow-up 4 months later, the patient was clinically better; his prostate-specific antigen had dramatically improved to 4.1μg/L and a re-staging computed tomography scan revealed complete resolution of his bulky lymphadenopathy. At the time, he was receiving a luteinising hormone-releasing hormone analogue but no other disease-modulating treatment. He remains well and asymptomatic, with his most recent serum prostate-specific antigen measuring 0.14μg/L, 18 months after last receiving chemotherapy.
We report a case of complete and durable regression of metastatic castrate-resistant prostate cancer following palliative chemotherapy which, to the best of our knowledge, has not previously been reported in the literature.
PMCID: PMC4000147  PMID: 24717107
Castrate-resistant prostate cancer; Chemotherapy; Complete response; PSA
15.  A Comprehensive Review of Contemporary Role of Local Treatment of the Primary Tumor and/or the Metastases in Metastatic Prostate Cancer 
BioMed Research International  2014;2014:501213.
To provide an overview of the currently available literature regarding local control of primary tumor and oligometastases in metastatic prostate cancer and salvage lymph node dissection of clinical lymph node relapse after curative treatment of prostate cancer. Evidence Acquisition. A systematic literature search was conducted in 2014 to identify abstracts, original articles, review articles, research articles, and editorials relevant to the local control in metastatic prostate cancer. Evidence Synthesis. Local control of primary tumor in metastatic prostate cancer remains experimental with low level of evidence. The concept is supported by a growing body of genetic and molecular research as well as analogy with other cancers. There is only one retrospective observational population based study showing prolonged survival. To eradicate oligometastases, several options exist with excellent local control rates. Stereotactic body radiotherapy is safe, well tolerated, and efficacious treatment for lymph node and bone lesions. Both biochemical and clinical progression are slowed down with a median time to initiate ADT of 2 years. Salvage lymph node dissection is feasible in patients with clinical lymph node relapse after local curable treatment. Conclusion. Despite encouraging oncologic midterm results, a complete cure remains elusive in metastatic prostate cancer patients. Further advances in imaging are crucial in order to rapidly evolve beyond the proof of concept.
PMCID: PMC4251412  PMID: 25485280
16.  Integrated Multimodal Imaging of Dynamic Bone-Tumor Alterations Associated with Metastatic Prostate Cancer 
PLoS ONE  2015;10(4):e0123877.
Bone metastasis occurs for men with advanced prostate cancer which promotes osseous growth and destruction driven by alterations in osteoblast and osteoclast homeostasis. Patients can experience pain, spontaneous fractures and morbidity eroding overall quality of life. The complex and dynamic cellular interactions within the bone microenvironment limit current treatment options thus prostate to bone metastases remains incurable. This study uses voxel-based analysis of diffusion-weighted MRI and CT scans to simultaneously evaluate temporal changes in normal bone homeostasis along with prostate bone metatastsis to deliver an improved understanding of the spatiotemporal local microenvironment. Dynamic tumor-stromal interactions were assessed during treatment in mouse models along with a pilot prospective clinical trial with metastatic hormone sensitive and castration resistant prostate cancer patients with bone metastases. Longitudinal changes in tumor and bone imaging metrics during delivery of therapy were quantified. Studies revealed that voxel-based parametric response maps (PRM) of DW-MRI and CT scans could be used to quantify and spatially visualize dynamic changes during prostate tumor growth and in response to treatment thereby distinguishing patients with stable disease from those with progressive disease (p<0.05). These studies suggest that PRM imaging biomarkers are useful for detection of the impact of prostate tumor-stromal responses to therapies thus demonstrating the potential of multi-modal PRM image-based biomarkers as a novel means for assessing dynamic alterations associated with metastatic prostate cancer. These results establish an integrated and clinically translatable approach which can be readily implemented for improving the clinical management of patients with metastatic bone disease.
Trial Registration NCT02064283
PMCID: PMC4393258  PMID: 25859981
17.  Chemoaffinity Capture of Pre-Targeted Prostate Cancer Cells with Magnetic Beads 
The Prostate  2012;72(14):1532-1541.
Prostate circulating tumor cells (PCTCs) in circulation are shed from either a primary tumor or metastases, which are directly responsible for most prostate cancer deaths. Quantifying exfoliated PCTCs may serve as an indicator for the clinical management of prostate cancer, isolating and removing of PCTCs could potentially reduce prostate cancer metastasis, and culturing and characterizing captured PCTCs could facilitate the development of personalized treatment options. Prostate-specific membrane antigen (PSMA) is an established biomarker for prostate cancer being strongly expressed on prostate tumor cells associated with high-grade primary, androgen independent, and metastatic tumors.
Suspensions of PSMA+ (LNCaP) cells were pre-targeted with the irreversible PSMA inhibitor biotin-PEG12-CTT-54 to serve as a bait to capture PSMA+ cells using streptavidin-coated magnetic beads. Decreasing numbers of LNCaP cells were spiked into blood to determine the cell captured efficiency, recovery and viability.
High selectivity, recovery, and viability were achieved for the capture of PSMA+ cells in both model experiments with mixtures of LNCaP cells and WBCs as well as blood samples spiked with LNCaP cells. As low as 10 cells were captured from 1 mL of blood with nearly 90% viability. More importantly, captured cells could be subsequently propagated in vitro.
This methodology for the detection, isolation, and culture of PCTCs from peripheral blood can serve as an effective tool for the detection of metastatic prostate cancer, treatment monitoring, and the development of personalized therapy based on the responsiveness of PCTCs to chemotherapeutic strategies.
PMCID: PMC3410962  PMID: 22488169
prostate cancer; circulating tumor cells; PSMA; prostate-specific membrane antigen; flow cytometry; magnetic bead
18.  Robotic-Assisted Minimally Invasive Surgery for Gynecologic and Urologic Oncology 
Executive Summary
An application was received to review the evidence on the ‘The Da Vinci Surgical System’ for the treatment of gynecologic malignancies (e.g. endometrial and cervical cancers). Limitations to the current standard of care include the lack of trained physicians on minimally invasive surgery and limited access to minimally invasive surgery for patients. The potential benefits of ‘The Da Vinci Surgical System’ include improved technical manipulation and physician uptake leading to increased surgeries, and treatment and management of these cancers.
The demand for robotic surgery for the treatment and management of prostate cancer has been increasing due to its alleged benefits of recovery of erectile function and urinary continence, two important factors of men’s health. The potential technical benefits of robotic surgery leading to improved patient functional outcomes are surgical precision and vision.
Clinical Need
Uterine and cervical cancers represent 5.4% (4,400 of 81,700) and 1.6% (1,300 of 81,700), respectively, of incident cases of cancer among female cancers in Canada. Uterine cancer, otherwise referred to as endometrial cancer is cancer of the lining of the uterus. The most common treatment option for endometrial cancer is removing the cancer through surgery. A surgical option is the removal of the uterus and cervix through a small incision in the abdomen using a laparoscope which is referred to as total laparoscopic hysterectomy. Risk factors that increase the risk of endometrial cancer include taking estrogen replacement therapy after menopause, being obese, early age at menarche, late age at menopause, being nulliparous, having had high-dose radiation to the pelvis, and use of tamoxifen.
Cervical cancer occurs at the lower narrow end of the uterus. There are more treatment options for cervical cancer compared to endometrial cancer, however total laparoscopic hysterectomy is also a treatment option. Risk factors that increase the risk for cervical cancer are multiple sexual partners, early sexual activity, infection with the human papillomavirus, and cigarette smoking, whereas barrier-type of contraception as a risk factor decreases the risk of cervical cancer.
Prostate cancer is ranked first in men in Canada in terms of the number of new cases among all male cancers (25,500 of 89,300 or 28.6%). The impact on men who develop prostate cancer is substantial given the potential for erectile dysfunction and urinary incontinence. Prostate cancer arises within the prostate gland, which resides in the male reproductive system and near the bladder. Radical retropubic prostatectomy is the gold standard treatment for localized prostate cancer. Prostate cancer affects men above 60 years of age. Other risk factors include a family history of prostate cancer, being of African descent, being obese, consuming a diet high in fat, physical inactivity, and working with cadium.
The Da Vinci Surgical System
The Da Vinci Surgical System is a robotic device. There are four main components to the system: 1) the surgeon’s console, where the surgeon sits and views a magnified three-dimensional image of the surgical field; 2) patient side-cart, which sits beside the patient and consists of three instrument arms and one endoscope arm; 3) detachable instruments (endowrist instruments and intuitive masters), which simulate fine motor human movements. The hand movements of the surgeon’s hands at the surgeon’s console are translated into smaller ones by the robotic device and are acted out by the attached instruments; 4) three-dimensional vision system: the camera unit or endoscope arm. The main advantages of use of the robotic device are: 1) the precision of the instrument and improved dexterity due to the use of “wristed” instruments; 2) three-dimensional imaging, with improved ability to locate blood vessels, nerves and tissues; 3) the surgeon’s console, which reduces fatigue accompanied with conventional laparoscopy surgery and allows for tremor-free manipulation. The main disadvantages of use of the robotic device are the costs including instrument costs ($2.6 million in US dollars), cost per use ($200 per use), the costs associated with training surgeons and operating room personnel, and the lack of tactile feedback, with the trade-off being increased visual feedback.
Research Questions
For endometrial and cervical cancers,
1. What is the effectiveness of the Da Vinci Surgical System vs. laparoscopy and laparotomy for women undergoing any hysterectomy for the surgical treatment and management of their endometrial and cervical cancers?
2. What are the incremental costs of the Da Vinci Surgical System vs. laparoscopy and laparotomy for women undergoing any hysterectomy for the surgical treatment and management of their endometrial and cervical cancers?
For prostate cancer,
3. What is the effectiveness of robotically-assisted radical prostatectomy using the Da Vinci Surgical System vs. laparoscopic radical prostatectomy and retropubic radical prostatectomy for the surgical treatment and management of prostate cancer?
4. What are the incremental costs of robotically-assisted radical prostatectomy using the Da Vinci Surgical System vs. laparoscopic radical prostatectomy and retropubic radical prostatectomy for the surgical treatment and management of prostate cancer?
Research Methods
Literature Search
Search Strategy
A literature search was performed on May 12, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, OVID EMBASE, Wiley Cochrane, CINAHL, Centre for Reviews and Dissemination/International Agency for Health Technology Assessment for studies published from January 1, 2000 until May 12, 2010. Abstracts were reviewed by a single reviewer and, for those studies meeting the eligibility criteria, full-text articles were obtained. Reference lists were also examined for any additional relevant studies not identified through the search. Articles with unknown eligibility were reviewed with a second clinical epidemiologist, then a group of epidemiologists until consensus was established. The quality of evidence was assessed as high, moderate, low or very low according to GRADE methodology.
Inclusion Criteria
English language articles (January 1, 2000-May 12, 2010)
Journal articles that report on the effectiveness or cost-effectiveness for the comparisons of interest using a primary data source (e.g. obtained in a clinical setting)
Journal articles that report on the effectiveness or cost-effectiveness for the comparisons of interest using a secondary data source (e.g. hospital- or population-based registries)
Study design and methods must be clearly described
Health technology assessments, systematic reviews, randomized controlled trials, non-randomized controlled trials and/or cohort studies, case-case studies, regardless of sample size, cost-effectiveness studies
Exclusion Criteria
Duplicate publications (with the more recent publication on the same study population included)
Non-English papers
Animal or in-vitro studies
Case reports or case series without a referent or comparison group
Studies on long-term survival which may be affected by treatment
Studies that do not examine the cancers (e.g. advanced disease) or outcomes of interest
Outcomes of Interest
For endometrial and cervical cancers,
Primary outcomes:
Morbidity factors
- Length of hospitalization
- Number of complications*
Peri-operative factors
- Operation time
- Amount of blood loss*
- Number of conversions to laparotomy*
Number of lymph nodes recovered
For prostate cancer,
Primary outcomes:
Morbidity factors
- Length of hospitalization
- Amount of morphine use/pain*
Peri-operative factors
- Operation time
- Amount of blood loss*
- Number of transfusions*
- Duration of catheterization
- Number of complications*
- Number of anastomotic strictures*
Number of lymph nodes recovered
Oncologic factors
- Proportion of positive surgical margins
Long-term outcomes
- Urinary continence
- Erectile function
Summary of Findings
Robotic use for gynecologic oncology compared to:
Laparotomy: benefits of robotic surgery in terms of shorter length of hospitalization and less blood loss. These results indicate clinical effectiveness in terms of reduced morbidity and safety, respectively, in the context of study design limitations.
The beneficial effect of robotic surgery was shown in pooled analysis for complications, owing to increased sample size.
More work is needed to clarify the role of complications in terms of safety, including improved study designs, analysis and measurement.
Laparoscopy: benefits of robotic surgery in terms of shorter length of hospitalization, less blood loss and fewer conversions to laparotomy likely owing to the technical difficulty of conventional laparoscopy, in the context of study design limitations.
Clinical significance of significant findings for length of hospitalizations and blood loss is low.
Fewer conversions to laparotomy indicate clinical effectiveness in terms of reduced morbidity.
Robotic use for urologic oncology, specifically prostate cancer, compared to:
Retropubic surgery: benefits of robotic surgery in terms of shorter length of hospitalization and less blood loss/fewer individuals requiring transfusions. These results indicate clinical effectiveness in terms of reduced morbidity and safety, respectively, in the context of study design limitations. There was a beneficial effect in terms of decreased positive surgical margins and erectile dysfunction. These results indicate clinical effectiveness in terms of improved cancer control and functional outcomes, respectively, in the context of study design limitations.
Surgeon skill had an impact on cancer control and functional outcomes.
The results for complications were inconsistent when measured as either total number of complications, pain management or anastomosis. There is some suggestion that robotic surgery is safe with respect to less post-operative pain management required compared to retropubic surgery, however improved study design and measurement of complications need to be further addressed.
Clinical significance of significant findings for length of hospitalizations is low.
Laparoscopy: benefits of robotic surgery in terms of less blood loss and fewer individuals requiring transfusions likely owing to the technical difficulty of conventional laparoscopy, in the context of study design limitations.
Clinical significance of significant findings for blood loss is low.
The potential link between less blood loss, improved visualization and improved functional outcomes is an important consideration for use of robotics.
All studies included were observational in nature and therefore the results must be interpreted cautiously.
Economic Analysis
The objective of this project was to assess the economic impact of robotic-assisted laparoscopy (RAL) for endometrial, cervical, and prostate cancers in the province of Ontario.
A budget impact analysis was undertaken to report direct costs associated with open surgery (OS), endoscopic laparoscopy (EL) and robotic-assisted laparoscopy (RAL) based on clinical literature review outcomes, to report a budget impact in the province based on volumes and costs from administrative data sets, and to project a future impact of RAL in Ontario. A cost-effectiveness analysis was not conducted because of the low quality evidence from the clinical literature review.
Hospital costs were obtained from the Ontario Case Costing Initiative (OCCI) for the appropriate Canadian Classification of Health Intervention (CCI) codes restricted to selective ICD-10 diagnostic codes after consultation with experts in the field. Physician fees were obtained from the Ontario Schedule of Benefits (OSB) after consultation with experts in the field. Fees were costed based on operation times reported in the clinical literature for the procedures being investigated. Volumes of procedures were obtained from the Ministry of Health and Long-Term Care (MOHLTC) administrative databases.
Direct costs associated with RAL, EL and OS included professional fees, hospital costs (including disposable instruments), radiotherapy costs associated with positive surgical margins in prostate cancer and conversion to OS in gynecological cancer. The total cost per case was higher for RAL than EL and OS for both gynecological and prostate cancers. There is also an acquisition cost associated with RAL. After conversation with the only supplier in Canada, hospitals are looking to spend an initial 3.6M to acquire the robotic surgical system
Previous volumes of OS and EL procedures were used to project volumes into Years 1-3 using a linear mathematical expression. Burden of OS and EL hysterectomies and prostatectomies was calculated by multiplying the number of cases for that year by the cost/case of the procedure.
The number of procedures is expected to increase in the next three years based on historical data. RAL is expected to capture this market by 65% after consultation with experts. If it’s assumed that RAL will capture the current market in Ontario by 65%, the net impact is expected to be by Year 3, 3.1M for hysterectomy and 6.7M for prostatectomy procedures respectively in the province.
RAL has diffused in the province with four surgical systems in place in Ontario, two in Toronto and two in London. RAL is a more expensive technology on a per case basis due to more expensive robot specific instrumentation and physician labour reflected by increased OR time reported in the clinical literature. There is also an upfront cost to acquire the machine and maintenance contract. RAL is expected to capture the market at 65% with project net impacts by Year 3 of 3.1M and 6.7M for hysterectomy and prostatectomy respectively.
PMCID: PMC3382308  PMID: 23074405
19.  Enzalutamide for patients with metastatic castration-resistant prostate cancer 
OncoTargets and therapy  2015;8:871-876.
To review and evaluate current literature on the US Food and Drug Administration (FDA)-approved drug enzalutamide (XTANDI®) in metastatic castration-resistant prostate cancer.
Data sources
Literature search was done through PubMed using the terms enzalutamide, MDV3100, abiraterone, and castration-resistant prostate cancer. Data from FDA product labels were also used.
Study selection and data extraction
Recent and relevant studies were included in the review. Collected clinical trials were screened and evaluated.
Data synthesis
Enzalutamide is an androgen receptor (AR) inhibitor with high selectivity and affinity to the AR. It was approved by the FDA to treat metastatic castration-resistant prostate cancer in patients previously treated with docetaxel, after a Phase III trial (AFFIRM) that showed a 4.8-month survival benefit in this population. Recently, the FDA expanded the approval of enzalutamide as first-line therapy for metastatic castration-resistant prostate cancer (mCRPC) who did not receive chemotherapy. Moreover, enzalutamide is shown to be associated with an acceptable safety profile.
Enzalutamide has been shown to be both safe and effective in improving overall survival in metastatic castration-resistant prostate cancer postchemotherapy with docetaxel and as a first line treatment before initiation of chemotherapy. However, additional studies and head-to-head trials are needed.
PMCID: PMC4407758  PMID: 25945058
enzalutamide; castration-resistant prostate cancer
20.  Androgen ablation mitigates tolerance to a prostate/prostate cancer-restricted antigen 
Cancer cell  2005;7(3):239-249.
To understand the T cell response to prostate cancer, we created transgenic mice that express a model antigen in a prostate-restricted pattern and crossed these animals to TRAMP mice that develop spontaneous prostate cancer. Adoptive transfer of prostate-specific CD4 T cells shows that, in the absence of prostate cancer, the prostate gland is mostly ignored. Tumorigenesis allows T cell recognition of the prostate gland—but this recognition is tolerogenic, resulting in abortive proliferation and ultimately in hyporesponsiveness at the systemic level. Androgen ablation (the most common treatment for metastatic prostate cancer) was able to mitigate this tolerance—allowing prostate-specific T cells to expand and develop effector function after vaccination. These results suggest that immunotherapy for prostate cancer may be most efficacious when administered after androgen ablation.
PMCID: PMC2846360  PMID: 15766662
21.  Prostate radiation in non-metastatic castrate refractory prostate cancer provides an interesting insight into biology of prostate cancer 
The natural history of non-metastatic castrate refractory prostate cancer is unknown and treatment options are limited. We present a retrospective review of 13 patients with locally advanced or high risk prostate cancer, initially treated with hormone monotherapy and then treated with prostate radiation after becoming castration refractory.
Median PSA response following prostate radiation was 67.4%. Median time to biochemical progression following radiotherapy was 15 months and to detection of metastatic disease was 18.5 months. Median survival from castration resistance (to date of death or November 2011) was 60 months, with median survival from RT 42 months.
Prostate radiation appears to be beneficial even in patients with potential micrometastatic disease, which supports the hypothesis that the primary tumour is important in the progression of prostate cancer. These results are an interesting addition to the literature on the biology of prostate cancer especially as this data is unlikely to be available in the future due to combined prostate radiation and androgen deprivation therapy now being the standard of care.
PMCID: PMC3348090  PMID: 22439942
Prostate cancer; Prostate radiation; Castrate refractory
22.  Comprehensive Evaluation of the Role of EZH2 in the Growth, Invasion, and Aggression of a Panel of Prostate Cancer Cell Lines 
The Prostate  2010;70(6):675-688.
Although most prostate cancers respond well to initial treatments, a fraction of prostate cancers are more aggressive and will recur and metastasize. At that point, there are few treatment options available. Significant efforts have been made to identify biomarkers that will identify these more aggressive cancers to tailor a more vigorous treatment in order to improve outcome. Polycomb Group protein Enhancer of Zeste 2 (EZH2) was found to be overexpressed in metastatic prostate tumors, and is considered an excellent candidate for such a biomarker. Scattered studies have found that EZH2 overexpression causes neoplastic transformation, invasion, and growth of prostate cells. However, these studies utilized different systems and cell lines, and so are difficult to correlate with one another.
In this study, a comprehensive evaluation of the phenotypic effects of EZH2 in a panel of five prostate cancer cell lines was performed. By using multiple cell lines, and examining overexpression and knockdown of EZH2 concurrently, a broad view of EZH2's role in prostate cancer was achieved.
Overexpression of EZH2 led to more aggressive behaviors in all prostate cell lines tested. In contrast, downregulation of EZH2 reduced invasion and tumorigenicity of androgen-independent cell lines CWR22Rv1, PC3, and DU145, but not of androgen-dependent cell lines LAPC4 and LNCaP.
Findings from this study suggest androgen-independent prostate tumors are more dependent on EZH2 expression than androgen-dependent tumors. Our observations provide an explanation for the strong correlation between EZH2 overexpression and advanced stage, aggressive prostate cancers.
PMCID: PMC2848714  PMID: 20087897
EZH2; Prostate; Cancer; Growth; Aggression
23.  Emerging novel therapies for advanced prostate cancer 
This review examines the development and efficacy of novel treatment options for advanced prostate cancer and discusses novel therapies that are on the horizon. Since the introduction of docetaxel as the standard treatment for patients with metastatic castration-resistant prostate cancer (CRPC), a number of different agents have been tested but failed to demonstrate improvement in overall survival (OS). Recently, three novel compounds have demonstrated OS benefit and one other showed reduction in skeletal-related events (SREs). Sipuleucel-T, a novel vaccine, was approved by the US regulatory authorities in April 2010 for patients with early advanced prostate cancer. A new taxane, cabazitaxel, and abiraterone acetate, an androgen biosynthesis inhibitor, have shown an OS benefit in advanced CRPC after docetaxel, leading to drug approval. A new bone-targeting agent, denosumab, a receptor activator of nuclear factor κB ligand (RANKL) antagonist, showed a modest reduction in SREs in comparison to zoledronic acid in patients with bone metastases. Other promising novel agents are currently being tested in the clinical setting of advanced CRPC. These include, androgen receptor inhibitors (MDV3100), androgen biosynthesis inhibitors, angiogenesis inhibitors (thalidomide, lenalidomine, aflibercept, tasquinimod), a novel form of radiotherapy (radium-223), and immune-modulating compounds (PROSTVAC-VF). Improvements in progression-free survival and OS rates, observed with novel agents, in metastatic prostate cancer have led to a shift in treatment paradigm. The challenge will be to position the current established and expected novel treatments in the new landscape of metastatic prostate cancer and to determine at what point and time in the disease course they can best be administered.
PMCID: PMC3263924  PMID: 22295041
abiraterone; cabazitaxel; castration-resistant prostate cancer; MDV3100; sipuleucel-T; denosumab; zoledronic acid
24.  High-Resolution Flow Cytometry: a Suitable Tool for Monitoring Aneuploid Prostate Cancer Cells after TMZ and TMZ-BioShuttle Treatment 
If metastatic prostate cancer gets resistant to antiandrogen therapy, there are few treatment options, because prostate cancer is not very sensitive to cytostatic agents. Temozolomide (TMZ) as an orally applicable chemotherapeutic substance has been proven to be effective and well tolerated with occasional moderate toxicity especially for brain tumors and an application to prostate cancer cells seemed to be promising. Unfortunately, TMZ was inefficient in the treatment of symptomatic progressive hormone-refractory prostate cancer (HRPC). The reasons could be a low sensitivity against TMZ the short plasma half-life of TMZ, non-adapted application regimens and additionally, the aneuploid DNA content of prostate cancer cells suggesting different sensitivity against therapeutical interventions e.g. radiation therapy or chemotherapy. Considerations to improve this unsatisfying situation resulted in the realization of higher local TMZ concentrations, sufficient to kill cells regardless of intrinsic cellular sensitivity and cell DNA-index. Therefore, we reformulated the TMZ by ligation to a peptide-based carrier system called TMZ-BioShuttle for intervention. The modular-composed carrier consists of a transmembrane transporter (CPP), connected to a nuclear localization sequence (NLS) cleavably-bound, which in turn was coupled with TMZ. The NLS-sequence allows an active delivery of the TMZ into the cell nucleus after transmembrane passage of the TMZ-BioShuttle and intra-cytoplasm enzymatic cleavage and separation from the CPP. This TMZ-BioShuttle could contribute to improve therapeutic options exemplified by the hormone refractory prostate cancer. The next step was to syllogize a qualified method monitoring cell toxic effects in a high sensitivity under consideration of the ploidy status. The high-resolution flow cytometric analysis showed to be an appropriate system for a better detection and distinction of several cell populations dependent on their different DNA-indices as well as changes in proliferation of cell populations after chemotherapeutical treatment.
PMCID: PMC2781174  PMID: 19946604
TMZ-BioShuttle; Prostate Cancer Cells; Flow Cytometry
25.  Loss of PDEF, a prostate-derived Ets factor is associated with aggressive phenotype of prostate cancer: Regulation of MMP 9 by PDEF 
Molecular Cancer  2010;9:148.
Prostate-derived Ets factor (PDEF) is expressed in tissues of high epithelial content including prostate, although its precise function has not been fully established. Conventional therapies produce a high rate of cure for patients with localized prostate cancer, but there is, at present, no effective treatment for intervention in metastatic prostate cancer. These facts underline the need to develop new approaches for early diagnosis of aggressive prostate cancer patients, and mechanism based anti-metastasis therapies that will improve the outlook for hormone-refractory prostate cancer. In this study we evaluated role of prostate-derived Ets factor (PDEF) in prostate cancer.
We observed decreased PDEF expression in prostate cancer cell lines correlated with increased aggressive phenotype, and complete loss of PDEF protein in metastatic prostate cancer cell lines. Loss of PDEF expression was confirmed in high Gleason Grade prostate cancer samples by immuno-histochemical methods. Reintroduction of PDEF profoundly affected cell behavior leading to less invasive phenotypes in three dimensional cultures. In addition, PDEF expressing cells had altered cell morphology, decreased FAK phosphorylation and decreased colony formation, cell migration, and cellular invasiveness. In contrast PDEF knockdown resulted in increased migration and invasion as well as clonogenic activity. Our results also demonstrated that PDEF downregulated MMP9 promoter activity, suppressed MMP9 mRNA expression, and resulted in loss of MMP9 activity in prostate cancer cells. These results suggested that loss of PDEF might be associated with increased MMP9 expression and activity in aggressive prostate cancer. To confirm results we investigated MMP9 expression in clinical samples of prostate cancer. Results of these studies show increased MMP9 expression correlated with advanced Gleason grade. Taken together our results demonstrate decreased PDEF expression and increased MMP9 expression during the transition to aggressive prostate cancer.
These studies demonstrate for the first time negative regulation of MMP9 expression by PDEF, and that PDEF expression was lost in aggressive prostate cancer and was inversely associated with MMP9 expression in clinical samples of prostate cancer. Based on these exciting results, we propose that loss of PDEF along with increased MMP9 expression should serve as novel markers for early detection of aggressive prostate cancer.
PMCID: PMC2904725  PMID: 20550708

Results 1-25 (519878)