Differentiating radiation injury from viable tumor is important for optimizing patient care. Our aim was to directly compare the effectiveness of fluorine-18 fluorodeoxyglucose (FDG) PET-CT and dynamic susceptibility-weighted contrast-enhanced (DSC) MR perfusion in differentiating radiation effects from tumor growth in patients with increased enhancement following radiotherapy for primary or secondary brain tumors.
Materials and Methods
We retrospectively identified 12 consecutive patients with primary and secondary brain tumors over a 1-year period that demonstrated indeterminate enhancing lesions after radiotherapy and that had undergone DSC MR perfusion, FDG PET-CT, and subsequent histopathologic diagnosis. The maximum SUV of the lesion (SUVlesion max), SUVratio (SUVlesion max/SUVnormal brain), maximum relative cerebral blood volume (rCBVmax), percentage of signal intensity recovery (PSR) and relative peak height (rPH) were calculated from the PET and MR perfusion studies. A prediction of tumor or radiation injury was made based on these variables while being blinded to the results of the surgical pathology.
SUVratio had the highest predictive value (area under the curve = 0.943) for tumor progression, although this was not statistically better than any MR perfusion metric (area under the curve = 0.757–0.829).
This preliminary study suggests that FDG PET-CT and DSC MR perfusion may demonstrate similar effectiveness for distinguishing tumor growth from radiation injury. Assessment of the SUVratio may increase the sensitivity and specificity of FDG PET-CT for differentiating tumor and radiation injury. Further analysis is needed to help define which modality has greater predictive capabilities.
Differentiating radiation injury and tumor; MRI perfusion versus FDG PET/CT; rCBVmax; PSR; rPH; SUVratio
The hypoxia-inducible factor and vascular endothelial growth factor (HIF-VEGF) pathway in hypoxic conditions of the middle ear due to dysfunction of the eustachian tube is still unknown, but it is considered as one pathogenetic mechanism in otitis media. This study was designed to investigate the possible involvement of the HIF-VEFG pathway in otitis media with effusion induced by dysfunction of the eustachian tube. We adopted a soft palate approach to obstruct the orifice of the eustachian tube to establish otitis media in a rat model. Auditory evoked brainstem response and tympanometry were used as hearing function tests, hypoxia-related factors were examined by reverse transcriptase polymerase chain reaction (RT-PCR). The expression of hypoxia-related proteins was detected by Western blot and immunostaining. The model of otitis media with effusion was successfully induced by cauterizing the orifice of the eustachian tube. RT-PCR showed up-regulation of hypoxia-related factors in cauterized ears. Western blot and immunostaining showed that the expression of hypoxia-related proteins in cauterized ears was increased. Hypoxia-induced vascular proliferation and an increase in permeability may be one pathogenetic mechanism of otitis media due to dysfunction of the eustachian tube.
Animal model; Dysfunction; Eustachian tube; Hypoxia-inducible factor-1 α; Vascular endothelial growth factor
Many studies have reported the prognostic predictive value of CD166 as a cancer stem cell marker in cancers of the digestive system; however, its predictive value remains controversial. Here, we investigate the correlation between CD166 positivity in digestive system cancers and clinicopathological features using meta-analysis.
A comprehensive search in PubMed and ISI Web of Science through March of 2013 was performed. Only articles containing CD166 antigen immunohistochemical staining in cancers of the digestive system were included,including pancreatic cancer, esophageal cancer, gastric cancer and colorectal cancer. Data comparing 3- and 5-year overall survival along with other clinicopathological features were collected.
Nine studies with 2553 patients who met the inclusion criteria were included for the analysis. The median rate of CD166 immunohistochemical staining expression was 56% (25.4%–76.3%). In colorectal cancer specifically, the results of a fixed-effects model indicated that CD166-positive expression was an independent marker associated with a smaller tumor burden (T category; RR = 0.93, 95%, CI: 0.88–0.98) but worse spread to nearby lymph nodes (N category; RR = 1.17, 95% CI: 1.05–1.30). The 5-year overall survival rate was showed relationship with cytoplasmic positive staining of CD166 (RR = 1.47 95% 1.21–1.79), but no significant association was found in the pool or any other stratified analysis with 3- or 5- year overall survival rate.
Based on the published studies, different cellular location of CD166 has distinct prognostic value and cytoplasmic positive expression is associated with worse prognosis outcome. Besides, our results also find CD166 expression indicate advanced T category and N-positive status in colorectal cancer specifically.
Accumulating evidence suggests that brachial plexopathy following head and neck cancer radiotherapy may be underreported and that this toxicity is associated with a dose–response. Our purpose was to determine whether the dose to the brachial plexus (BP) can be constrained, without compromising regional control.
The radiation plans of 324 patients with oropharyngeal carcinoma (OPC) treated with intensity-modulated radiation therapy (IMRT) were reviewed. We identified 42 patients (13%) with gross nodal disease <1 cm from the BP. Normal tissue constraints included a maximum dose of 66 Gy and a D05 of 60 Gy for the BP. These criteria took precedence over planning target volume (PTV) coverage of nodal disease near the BP.
There was only one regional failure in the vicinity of the BP, salvaged with neck dissection (ND) and regional re-irradiation. There have been no reported episodes of brachial plexopathy to date.
In combined-modality therapy, including ND as salvage, regional control did not appear to be compromised by constraining the dose to the BP. This approach may improve the therapeutic ratio by reducing the long-term risk of brachial plexopathy.
Brachial plexopathy; Intensity-modulated radiation therapy; Oropharyngeal carcinoma; Cisplatin; Cetuximab
External guide sequences (EGSs) are RNA molecules that consist of a sequence complementary to a target mRNA and recruit intracellular ribonuclease P (RNase P), a tRNA processing enzyme, for specific degradation of the target mRNA. We have previously used an in vitro selection procedure to generate EGS variants that efficiently induce human RNase P to cleave a target mRNA in vitro. In this study, we constructed EGSs from a variant to target the overlapping region of the S mRNA, pre-S/L mRNA, and pregenomic RNA (pgRNA) of hepatitis B virus (HBV), which are essential for viral replication and infection. The EGS variant was about 50-fold more efficient in inducing human RNase P to cleave the mRNA in vitro than the EGS derived from a natural tRNA. Following Salmonella-mediated gene delivery, the EGSs were expressed in cultured HBV-carrying cells. A reduction of about 97% and 75% in the level of HBV RNAs and proteins and an inhibition of about 6,000- and 130-fold in the levels of capsid-associated HBV DNA were observed in cells treated with Salmonella vectors carrying the expression cassette for the variant and the tRNA-derived EGS, respectively. Our study provides direct evidence that the EGS variant is more effective in blocking HBV gene expression and DNA replication than the tRNA-derived EGS. Furthermore, these results demonstrate the feasibility of developing Salmonella-mediated gene delivery of highly active EGS RNA variants as a novel approach for gene-targeting applications such as anti-HBV therapy.
β-catenin plays a key role in the progression of colorectal cancer (CRC). However, its prognostic significance for patients with CRC remains controversial.
Identical search strategies were used to search relevant literatures in the PubMed, Embase and Web of Science databases. The correlation between β-catenin expression and clinicopathological features and prognosis was analyzed.
A total of 18 studies met the inclusion criteria, which comprised 3665 cases. Meta-analysis suggested that β-catenin overexpression in the nucleus was significantly associated with disease free survival (DFS) (n = 541 in 3 studies; HR = 1.87, 95% CI: 1.28–2.71; Z = 3.26; P = 0.001) and overall survival (OS) for CRC patients (n = 2630 in 10 studies; HR = 1.55, 95% CI: 1.12–2.14; Z = 2.62; P = 0.009). However, there was no significant association between β-catenin expression in the cytoplasm and OS (n = 1327 in 3 studies; HR = 1.04, 95% CI: 0.88–1.24, Z = 0.46, P = 0.643). The combined odds ratio (OR) of β-catenin in the nucleus indicated that β-catenin overexpression was associated with advanced stage CRC (n = 950 in 7 studies; OR = 0.71, 95% CI: 0.53–0.94; Z = 2.35; P = 0.019) and metastasis of CRC (n = 628 in 5 studies; OR = 0.49, 95% CI: 0.25–0.96, Z = 2.06, P = 0.039). β-catenin overexpression in the nucleus had no correlation with the tumor site (colon or rectum), differentiation grade, lymph node status or depth of invasion. The pooled ORs were 1.09 (95% CI: 0.41–2.91, Z = 0.18, P = 0.856), 1.27(95% CI: 0.76–2.10, Z = 0.92, P = 0.357), 0.71(95% CI: 0.46–1.09, Z = 1.58, P = 0.115) and 0.82(95% CI: 0.4–1.68, Z = 0.53, P = 0.594).
This study showed that β-catenin overexpression in the nucleus, rather than in the cytoplasm, appeared to be associated with progress disease and a worse prognosis for CRC patients.
Patients treated for a thoracic malignancy carry a significant risk of developing other lung lesions. Locoregional control of intrathoracic recurrences is challenging due to the impact of prior therapies on normal tissues. We examined the safety and efficacy of thoracic re-irradiation using high-precision image-guided stereotactic body radiation therapy (SBRT).
Records of 39 patients with prior intra-thoracic conventionally fractionated radiation therapy (RT) who underwent SBRT for a subsequent primary, recurrent or metastatic lung tumor from 11/2004 to 7/2011 were retrospectively reviewed.
Median dose of prior RT was 61 Gy (range 30–80 Gy). Median biologically effective prescription dose (α/β = 10) (BED10) of SBRT was 70.4 Gy (range 42.6-180 Gy). With a median followup of 12.6 months among survivors, 1- and 2-year actuarial local progression-free survival (LPFS) were 77% and 64%, respectively. Median recurrence-free (RFS) and overall survival (OS) were 13.8 and 22.0 months, respectively. Patients without overlap of high-dose regions of the primary and re-irradiation plans were more likely to receive a BED10 ≥100 Gy, which was associated with higher LPFS (hazard ratio, [HR] = 0.18, p = 0.04), RFS ([HR] = 0.31, p = 0.038) and OS ([HR] = 0.25, p = 0.014). Grade 2 and 3 pulmonary toxicity was observed in 18% and 5% of patients, respectively. Other grade 2–4 toxicities included chest wall pain in 18%, fatigue in 15% and skin toxicity in 5%. No grade 5 events occurred.
SBRT can be safely and successfully administered to patients with prior thoracic RT. Dose reduction for cases with direct overlap of successive radiation fields results in acceptable re-treatment toxicity profile.
Lung re-irradiation; SBRT; Pulmonary toxicity; BED
Colorectal cancer (CRC) is one of the most prevalent cancers globally and is one of the leading causes of cancer-related deaths due to therapy resistance and metastasis. Understanding the mechanism underlying colorectal carcinogenesis is essential for the diagnosis and treatment of CRC. microRNAs (miRNAs) can act as either oncogenes or tumor suppressors in many cancers. A tumor suppressor role for miR-27b has recently been reported in neuroblastoma, while no information about miR-27b in CRC is available. In this study, we demonstrated that miR-27b expression is decreased in most CRC tissues and determined that overexpression of miR-27b represses CRC cell proliferation, colony formation and tumor growth in vitro and in vivo. We identified vascular endothelial growth factor C (VEGFC) as a novel target gene of miR-27b and determined that miR-27b functioned as an inhibitor of tumor progression and angiogenesis through targeting VEGFC in CRC. We further determined that DNA hypermethylation of miR-27b CpG islands decreases miR-27b expression. In summary, an anti-tumor role for miR-27b and its novel target VEGFC in vivo could lead to tumor necrosis and provide a rationale for developing miR-27b as a therapeutic agent.
Cancer-related fatigue (CRF) is an underestimated phenomenon and is prevalent in head and neck cancer patients. Results on aspects of the time course of CRF and its correlation with pain as well as the impact of pain on CRF are discussed.
After completing this course, the reader will be able to:
Discuss the incidence of cancer-related fatigue and the impact it has on cancer patients.Evaluate clinical correlates of cancer-related fatigue and describe possible interventions.Explain the time course of cancer-related fatigue before, during, and post-treatment and the effect treatment has on patients for years after treatment.
This article is available for continuing medical education credit at CME.TheOncologist.com
Cancer-related fatigue (CRF) is a highly prevalent and underestimated symptom in cancer patients. This study aims to analyze CRF solely in a cohort of oropharyngeal cancer patients who underwent treatment with radiotherapy (RT).
In January 2008 to June 2010, 87 consecutive oropharyngeal carcinoma patients underwent definitive RT. Concurrent chemotherapy was used for 94% of patients. The median prescription dose to the planning target volume of the gross or clinical tumor volume was 70 Gy for definitive cases (n = 84) and 66 Gy for postoperative cases (n = 3), both delivered over 6.5 weeks. A normalized 12-point numeric rating scale assessed CRF from patient visits before, during, and after RT.
The median follow-up of living patients was 14 months. Fatigue peaked 1–2 weeks post-RT and remained higher than baseline for up to 2 years post-RT in 50% of patients. The average fatigue score at the time of completion of therapy or maximum thereafter up to 1 year post-RT was significantly worse than baseline. Patients who experienced pain had a trend toward significance with association for a higher maximum difference in fatigue from baseline. Karnofsky performance status score, weight change, and mood disorders did not correlate with CRF.
Fatigue was a common treatment-related symptom in this uniform cohort of patients with oropharyngeal cancer. RT was highly correlated with worsening of CRF. Pain control has the potential to help mitigate CRF in patients experiencing pain, and will need to be confirmed using larger datasets.
Oropharynx; Fatigue; Pain; Radiotherapy; Cancer; Chemotherapy; Head and neck; Pain
The aim of this study is to expand existing knowledge about the CRC-associated microbiome among Han Chinese, and to further discover the variation pattern of the human CRC microbiome across all population.
Using pyrosequencing-based molecular monitoring of bacterial 16S rRNA gene from eight tumor/normal tissue pairs of eight Chinese CRC patients, we analyzed and characterized the basic features of the CRC-associated microbiome. Firstly, we discovered an increasing diversity among tumor-associated bacterial communities. Secondly, in 50% of Chinese CRC patients, we found a significant increase of Roseburia (P = 0.017), and a concurrent decrease of both Microbacterium (P = 0.009) and Anoxybacillus (P = 0.009) in tumor tissue.
We discovered a novel CRC microbiome pattern in Chinese. Both the over-represented Roseburia bacteria at tumor sites and the over-represented Microbacterium and Anoxybacillus bacteria away from tumor sites were both closely related in Chinese CRC patients. Across several populations reported in this study and previously, we observed both common and distinctive patterns of human CRC microbiome’s association with a high-risk of CRC.
Chinese; CRC; Microbiome; Pyrosequencing
The reported high rate of local recurrence (LR) in myxofibrosarcoma raises the question of whether this sarcoma histology should be considered radioresistant. We compared rates and patterns of LR of high-grade (HG) myxofibrosarcoma to HG leiomyosarcoma, chosen due to similarity in incidence and general treatment approach.
202 patients with primary non-metastatic extremity myxofibrosarcoma (n = 114) and leiomyosarcoma (n = 88) underwent limb-sparing surgery and were prospectively followed. All 202 patients had HG tumors; 138 (68%) received adjuvant radiotherapy.
The groups were comparable in age, sex, and chemotherapy use. Compared with leiomyosarcoma, myxofibrosarcoma presented more frequently with tumors >5 cm (p < 0.001), deep location (p = 0.036), and upper extremity site (p = 0.015). In addition, rates of positive/close margins (p < 0.001) and use of RT (<0.001) were significantly higher in myxofibrosarcoma. The 5-year overall LR rate was not significantly different according to histology: 14.6% for myxofibrosarcoma, 13.2% for leiomyosarcoma (p = 0.594). The only predictor of LR for the whole cohort of patients was positive/close margins (p = 0.01). Of 17 myxofibrosarcoma LRs, 8 (47%) occurred out of field, vs 1 of 12 (8%) leiomyosarcoma LRs (p=0.04). Leiomyosarcoma more commonly recurred distantly (54.1 vs 24.3% at 5 years, p=0.014)
Despite more adverse clinical features, myxofibrosarcoma recurred less often distantly than leiomyosarcoma whereas the LR rate was comparable between the two groups, suggesting that adjuvant RT is effective in myxofibrosarcoma. Myxofibrosarcoma LRs more commonly occurred out of field. Reduction in radiation-field margins may not be advisable in myxofibrosarcoma.
soft tissue sarcoma; local recurrence; radiation; myxofibrosarcoma
To study renalase's expression and distribution in renal tissues and cells, renalase coded DNA vaccine was constructed, and anti-renalase monoclonal antibodies were produced using DNA immunization and hybridoma technique, followed by further investigation with immunological testing and western blotting to detect the expression and distribution of renalase among the renal tissue and cells. Anti-renalase monoclonal antibodies were successfully prepared by using DNA immunization technique. Further studies with anti-renalase monoclonal antibody showed that renalase expressed in glomeruli, tubule, mesangial cells, podocytes, renal tubule epithelial cells and its cells supernatant. Renalase is wildly expressed in kidney, including glomeruli, tubule, mesangial cells, podocytes and tubule epithelial cells, and may be secreted by tubule epithelial cells primarily.
Melanoma cell adhesion molecule (MCAM) is a cell adhesion molecule that is abnormally expressed in a variety of tumours and is closely associated with tumour metastasis. The role of MCAM in ovarian cancer development has not been fully studied. In this study, through immunohistochemical staining of ovarian cancer tissue samples and RNA interference to silence MCAM in ovarian cancer cells, we examined the impact of MCAM on the biological functions of ovarian cancer cells and attempted to reveal the role of MCAM in ovarian cancer development. Our results showed that MCAM expression was particularly high in metastatic ovarian cancers compared with other pathological types of ovarian epithelial tissues. After MCAM silencing in the MCAM high-expression ovarian cancer cell line SKOV-3, the cell apoptosis was increased, whereas the cell spreading and invasion were significantly reduced, which may be related with dysregulation of small RhoGTPase (RhoA and Cdc42).These results suggest that MCAM expression in ovarian cancer is highly correlated with the metastatic potential of the cancer. MCAM is likely to participate in the regulation of the Rho signalling pathway to protect ovarian cancer cells from apoptosis and promote their malignant invasion and metastasis. Therefore, MCAM can be used not only as a molecular marker to determine the prognosis of ovarian cancer but also as a therapeutic target in metastatic ovarian cancer.
MCAM; Ovarian cancer; Spreading; Invasion; Apoptosis
In the setting of high-dose single-fraction image-guided radiotherapy of spine metastases, the delivered dose is hypothesized to be a significant factor in local control. We investigated the dependence of local control on measures of dose insufficiency.
Methods and Materials
The minimum doses received by the hottest 100%, 98%, and 95% (Dmin, D98, and D95) of the gross target volume (GTV) were computed for 91 consecutively treated lesions observed in 79 patients. Prescribed doses of 18–24 Gy were delivered in a single fraction. The spinal cord and cauda equina were constrained to a maximum dose of 12–14 Gy and 16 Gy, respectively. A rank-sum test was used to assess the differences between radiographic local failure and local control.
With a median follow-up of 18 months, seven local failures have occurred. The distributions of GTV Dmin, D98, and D95 for treatments resulting in local failure were found to be statistically different from the corresponding distributions of the patient group as a whole. Taking no account of histology, p values calculated for Dmin, D98, and D95 were 0.004, 0.012, and 0.031, respectively. No correlations between local failure and target volume or between local failure and anatomic location were found.
The results indicate that Dmin, D98, and D95 may be important risk factors for local failure. No local failures in any histology were observed when Dmin was >15 Gy, suggesting that this metric may be an important predictor of local control.
Paraspinal metastasis; High-dose single-fraction radiotherapy; Local failure; Dose insufficiency
PIM kinase expression in human lymphomas can influence the outcome of chemotherapy, and blocking cap-dependent translation can reverse PIM-mediated rapamycin resistance in murine lymphomas.
New anticancer drugs that target oncogenic signaling molecules have greatly improved the treatment of certain cancers. However, resistance to targeted therapeutics is a major clinical problem and the redundancy of oncogenic signaling pathways provides back-up mechanisms that allow cancer cells to escape. For example, the AKT and PIM kinases produce parallel oncogenic signals and share many molecular targets, including activators of cap-dependent translation. Here, we show that PIM kinase expression can affect the clinical outcome of lymphoma chemotherapy. We observe the same in animal lymphoma models. Whereas chemoresistance caused by AKT is readily reversed with rapamycin, PIM-mediated resistance is refractory to mTORC1 inhibition. However, both PIM- and AKT-expressing lymphomas depend on cap-dependent translation, and genetic or pharmacological blockade of the translation initiation complex is highly effective against these tumors. The therapeutic effect of blocking cap-dependent translation is mediated, at least in part, by decreased production of short-lived oncoproteins including c-MYC, Cyclin D1, MCL1, and the PIM1/2 kinases themselves. Hence, targeting the convergence of oncogenic survival signals on translation initiation is an effective alternative to combinations of kinase inhibitors.
Most patients with Hodgkin lymphoma (HL) are cured with first and second-line treatment; however for those who fail high dose chemoradiotherapy with autologous stem cell transplant (HDT-ASCT), outcome is unknown. This report is an analysis of patients with relapsed and primary refractory HL who were treated with HDT-ASCT and failed due to progression of disease (POD). Two hundred and two patients received HDT-ASCT at Memorial Sloan Kettering Cancer Center for relapsed or refractory HL between December 1994 and December 2005 and 71 failed due to POD. The median survival following HDT-ASCT failure was 25 months. Only 16 (23%) of the 71 patients are currently alive, 9 of whom are in remission. Multivariate analysis revealed two factors associated with poor outcome: relapse within 6 months of HDT-ASCT and primary refractory disease. The only factor associated with improved survival was the ability to receive a second transplant, in particular, reduced intensity allogeneic transplant (RIT). Novel therapies are needed for patients who fail HDT-ASCT, particularly those with primary refractory disease and those who relapse within 6 months of HDT-ASCT. Future studies should focus on prospectively evaluating RIT following HDT-ASCT failure in patients with remission duration from HDT-ASCT of greater than 6 months.
OTUB1 is a member of OTUs (Ovarian-tumor-domain-containing proteases), a deubiquitinating enzymes family (DUBs), which was shown as a proteasome-associated DUB to be involved in the proteins Ub-dependent degradation. It has been reported that OTUB1 was expressed in kidney tissue. But its concrete cellular location and function in the kidney remain unclear. Decorin (DCN) in mesangial cells (MC) is considered to be a potentially important factor for antagonizing glomerulonephritides, and its degradation is mediated by ubiquitination. The aim of this study is to investigate the role of OTUB1 expression in MC and its relationship with DCN during glomerulonephritis.
Using quantitative RT-PCR and Western blot, we demonstrated that OTUB1 mRNA and protein were constitutively expressed in cultured rat MC and found to be upregulated by the stimulation of IL-1β or ATS. OTUB1 overexpression was detected in the mesangial area of glomeruli in some immunocomplex mediated nephritides such as IgA nephropathy, acute diffuse proliferative glomerulonephritis and lupus nephritis by immunohistochemistry. The immunoprecipitation assay demonstrated that OTUB1 interacted with DCN. The overexpression of OTUB1 enhanced the ubiquitination and degradation of DCN in MC.
These data showed the inflammatory injury could up-regulate OTUB1 expression in MC, which might attribute the promoting effect of OTUB1 on glomerulonephritides to the decrease of DCN level.
Trimethoprim is a widely prescribed antibiotic for a variety of bacterial infections. It belongs to a class of anti-metabolites - antifolates - which includes drugs used against malarial parasites and in cancer therapy. However, spread of bacterial resistance to the drug has severely hampered its clinical use and has necessitated further investigations into its mechanism of action and treatment regimen. Trimethoprim selectively starves bacterial cells for tetrahydrofolate, a vital cofactor necessary for the synthesis of several metabolites. The outcome (bacteriostatic or bactericidal) of such starvation, however, depends on the availability of folate-dependent metabolites in the growth medium. To characterize this dependency, we investigated in detail the regulatory and structural components of Escherichia coli cellular response to trimethoprim in controlled growth and supplementation conditions.
We surveyed transcriptional responses to trimethoprim treatment during bacteriostatic and bactericidal conditions and analyzed associated gene sets/pathways. Concurrent starvation of all folate dependent metabolites caused growth arrest, and this was accompanied by induction of general stress and stringent responses. Three gene sets were significantly associated with the bactericidal effect of TMP in different media including LB: genes of the SOS regulon, genes of the pyrimidine nucleotide biosynthetic pathway and members of the multiple antibiotic resistance (mar) regulon controlled by the MarR repressor. However, the SOS response was identified as the only universal transcriptional signature associated with the loss of viability by direct thymine starvation or by folate stress. We also used genome-wide gene knock-out screen to uncover means of sensitization of bacteria to the drug. We observed that among a number of candidate genes and pathways, the effect of knock-outs in the deoxyribose nucleotide salvage pathway, encoded by the deoCABD operon and under the control of the DeoR repressor, was most informative.
Transcriptional induction of DNA damage response is an essential feature of the bactericidal effect of trimethoprim. Either the observation of the transcriptional response or DNA damage itself, or both, is made possible by thymine starvation when other folate-dependent metabolites are not limited. The effect of DNA damage by the drug takes place prior to its bactericidal effect, at the beginning of the lag stage of the treatment. Mutations in the deoxyribose nucleotide salvage pathway can affect duration of the lag as well as the rate of killing. This information can be used to postulate certain mechanistic differences between direct thymine starvation in thymidylate synthase deficient mutants and thymine starvation by anti-folate inhibitors.
To investigate whether pre-treatment endorectal magnetic resonance imaging (MRI) findings can predict biochemical relapse in patients with clinically localized prostate cancer (PCa) treated with external-beam radiation therapy (EBRT).
Patients and Methods
Between January 2000 and January 2002, 224 patients (median age 69 years, range 45-82) with biopsy-proven PCa underwent endorectal MRI before high-dose (≥ 81 Gy) EBRT. The value of multiple clinical and MRI variables in predicting PSA relapse at 5 years was determined using univariate and multivariate stepwise Cox regression. Clinical variables included pre-treatment PSA, clinical T-stage, Gleason score, use of neoadjuvant hormonal therapy and radiation dose. MRI variables, derived from retrospective consensus readings by two radiologists, measured intraprostatic and extraprostatic tumor burden.
After median follow-up of 67 months, 37 patients (16.5%) developed PSA relapse. The significant predictors of PSA relapse in univariate analysis were pre-treatment PSA, clinical T-stage, and multiple MRI variables including MRI TN-stage score; extracapsular extension (ECE) status; number of sextants involved by ECE, all lesions, or index (dominant) lesion; apical involvement; and diameter and volume of index lesion. Pretreatment PSA and ECE status were the only significant independent predictors upon multivariate analysis (P< 0.05 for both). ECE status was associated with the highest hazard ratio of 3.04; 5-year PSA relapse rates were 7% for no ECE, 20% for unilateral ECE, and 48% for bilateral ECE.
MRI findings can be used to predict post-EBRT PSA relapse, with ECE status on MRI and pre-treatment PSA being significant independent predictors of this endpoint.
MR imaging; prostate cancer; external beam radiation therapy; biochemical recurrence; extracapsular extension
Diabetic nephropathy is one of the major causes of renal failure, which is accompanied by the production of reactive oxygen species (ROS). Nrf2 is the primary transcription factor that controls the antioxidant response essential for maintaining cellular redox homeostasis. Here, we report our findings demonstrating a protective role of Nrf2 against diabetic nephropathy.
RESEARCH DESIGN AND METHODS
We explore the protective role of Nrf2 against diabetic nephropathy using human kidney biopsy tissues from diabetic nephropathy patients, a streptozotocin-induced diabetic nephropathy model in Nrf2−/− mice, and cultured human mesangial cells.
The glomeruli of human diabetic nephropathy patients were under oxidative stress and had elevated Nrf2 levels. In the animal study, Nrf2 was demonstrated to be crucial in ameliorating streptozotocin-induced renal damage. This is evident by Nrf2−/− mice having higher ROS production and suffering from greater oxidative DNA damage and renal injury compared with Nrf2+/+ mice. Mechanistic studies in both in vivo and in vitro systems showed that the Nrf2-mediated protection against diabetic nephropathy is, at least, partially through inhibition of transforming growth factor-β1 (TGF-β1) and reduction of extracellular matrix production. In human renal mesangial cells, high glucose induced ROS production and activated expression of Nrf2 and its downstream genes. Furthermore, activation or overexpression of Nrf2 inhibited the promoter activity of TGF-β1 in a dose-dependent manner, whereas knockdown of Nrf2 by siRNA enhanced TGF-β1 transcription and fibronectin production.
This work clearly indicates a protective role of Nrf2 in diabetic nephropathy, suggesting that dietary or therapeutic activation of Nrf2 could be used as a strategy to prevent or slow down the progression of diabetic nephropathy.
We assessed the effect of radical prostatectomy (RP) and external beam radiotherapy (EBRT) on distant metastases (DM) rates in patients with localized prostate cancer treated with RP or EBRT at a single specialized cancer center.
Patients and Methods
Patients with clinical stages T1c-T3b prostate cancer were treated with intensity-modulated EBRT (≥ 81 Gy) or RP. Both cohorts included patients treated with salvage radiotherapy or androgen-deprivation therapy for biochemical failure. Salvage therapy for patients with RP was delivered a median of 13 months after biochemical failure compared with 69 months for EBRT patients. DM was compared controlling for patient age, clinical stage, serum prostate-specific antigen level, biopsy Gleason score, and year of treatment.
The 8-year probability of freedom from metastatic progression was 97% for RP patients and 93% for EBRT patients. After adjustment for case mix, surgery was associated with a reduced risk of metastasis (hazard ratio, 0.35; 95% CI, 0.19 to 0.65; P < .001). Results were similar for prostate cancer–specific mortality (hazard ratio, 0.32; 95% CI, 0.13 to 0.80; P = .015). Rates of metastatic progression were similar for favorable-risk disease (1.9% difference in 8-year metastasis-free survival), somewhat reduced for intermediate-risk disease (3.3%), and more substantially reduced in unfavorable-risk disease (7.8% in 8-year metastatic progression).
Metastatic progression is infrequent in men with low-risk prostate cancer treated with either RP or EBRT. RP patients with higher-risk disease treated had a lower risk of metastatic progression and prostate cancer–specific death than EBRT patients. These results may be confounded by differences in the use and timing of salvage therapy.
The mean residual life function is an attractive alternative to the survival function or the hazard function of a survival time in practice. It provides the remaining life expectancy of a subject surviving up to time t. In this study, we propose a class of transformed mean residual life models for fitting survival data under right censoring. To estimate the model parameters, we make use of the inverse probability of censoring weighting approach and develop a system of estimating equations. Efficiency and robustness of the estimators are also studied. Both asymptotic and finite sample properties of the proposed estimators are established and the approach is applied to two real-life datasets collected from clinical trials.
Censored survival data; Estimating equation approach; Inverse probability of censoring weighting; Mean residual life; Semiparametric efficiency; Transformed models
Infection of host cells with human cytomegalovirus (HCMV) induces cell cycle dysregulation. Two HCMV immediate-early (IE) proteins, IE1-72 and IE2-86, are promiscuous transactivators that have been implicated in the dysregulatory events. Cellular p53 protein is accumulated to high levels in HCMV-infected cells, but the indicative marker of p53 transcriptional activity, p21, is markedly decreased. Both IE1-72 and IE2-86 were able to transactivate the p53 promoter and interact with p53 protein in DNA-transfected or HCMV-infected cells. HCMV UL84, a multiregulatory protein expressed in early periods of HCMV infection, also interacted with p53. HCMV IE1-72 prevented or disrupted p53 binding to p53-specific DNA sequences, while IE2-86 and/or UL84 enhanced p53 binding and induced supershift of this DNA-protein complex. Both HCMV IE1-72 and IE2-86 were able to inhibit p53-dependent transcriptional activation in plasmid-transfected cells. IE1-72, rather than IE2-86, was found to be responsible for p21 downregulation in HCMV-infected HEL cells. DNA transfection analysis using IE1-72 mutants revealed that exon 2/3 and the zinc finger region of IE1-72 are essential for IE1-72's effect on the repression of p53-dependent transcriptional activation. These data suggest that HCMV IE1-72 and/or IE2-86 transactivates the p53 promoter and induces p53 accumulation, but HCMV IE1-72 represses the p53 transactivation activity by a unique binding hindrance mechanism different from that of IE2-86. Thus, various modes of viral IE proteins and p53 interactions might result in multiple outcomes, such as stimulation of cellular DNA synthesis, cell cycle progression and cell cycle arrest, and prevention of program cell death.
While antisense oligonucleotide (AS-ODN) technology holds promise for the treatment of cancer, to date there have been no clinical successes. Unfortunately, current assays are not sufficiently sensitive to measure tissue ODN levels. Hence it has not been possible to ascertain whether treatment failures result from failure of drug delivery. To investigate the relationship between drug uptake and therapeutic effect, we developed an ultrasensitive noncompetitive hybridization-ligation enzyme-linked immunosorbent assay (NCHL-ELISA) to quantify Kinase Suppressor of Ras1 (KSR1) AS-ODN drug uptake in plasma and tumor tissues. In mice harboring PANC-1 pancreatic cancer xenografts and continuously infused with AS-ODN, our ELISA detects plasma and tumor KSR1 AS-ODN levels over an extended range, from 0.05 nM to 20 nM. Using this sensitive assay, we demonstrate that KSR1 repression in pancreatic cancer xenografts correlates highly with AS-ODN uptake into tumor tissues. In contrast, plasma drug levels do not correlate with tumor drug content or target downregulation. These studies indicate the efficacy of our ELISA, and suggest that tumor biopsy material will need to be procured to estimate the potential of this antisense technology.
KSR1; pancreatic cancer; antisense oligonucleotide; ELISA; drug uptake