Search tips
Search criteria

Results 1-25 (54)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Modulation of in Vivo Tumor Radiation Response via Gold Nanoshell-Mediated Vascular-Focused Hyperthermia: Characterizing an Integrated Antihypoxic and Localized Vascular Disrupting Targeting Strategy 
Nano letters  2008;8(5):1492-1500.
We report noninvasive modulation of in vivo tumor radiation response using gold nanoshells. Mild-temperature hyperthermia generated by near-infrared illumination of gold nanoshell-laden tumors, noninvasively quantified by magnetic resonance temperature imaging, causes an early increase in tumor perfusion that reduces the hypoxic fraction of tumors. A subsequent radiation dose induces vascular disruption with extensive tumor necrosis. Gold nanoshells sequestered in the perivascular space mediate these two tumor vasculature-focused effects to improve radiation response of tumors. This novel integrated antihypoxic and localized vascular disrupting therapy can potentially be combined with other conventional antitumor therapies.
PMCID: PMC3952070  PMID: 18412402
2.  Prevention and Treatment of Colorectal Cancer by Natural Agents From Mother Nature 
Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the United States after cancers of the lung and the breast/prostate. While the incidence of CRC in the United States is among the highest in the world (approximately 52/100,000), its incidence in countries in India is among the lowest (approximately 7/100,000), suggesting that lifestyle factors may play a role in development of the disease. Whereas obesity, excessive alcohol consumption, a high-calorie diet, and a lack of physical activity promote this cancer, evidence indicates that foods containing folates, selenium, Vitamin D, dietary fiber, garlic, milk, calcium, spices, vegetables, and fruits are protective against CRC in humans. Numerous agents from “mother nature” (also called “nutraceuticals,”) that have potential to both prevent and treat CRC have been identified. The most significant discoveries relate to compounds such as cardamonin, celastrol, curcumin, deguelin, diosgenin, thymoquinone, tocotrienol, ursolic acid, and zerumbone. Unlike pharmaceutical drugs, these agents modulate multiple targets, including transcription factors, growth factors, tumor cell survival factors, inflammatory pathways, and invasion and angiogenesis linked closely to CRC. We describe the potential of these dietary agents to suppress the growth of human CRC cells in culture and to inhibit tumor growth in animal models. We also describe clinical trials in which these agents have been tested for efficacy in humans. Because of their safety and affordability, these nutraceuticals provide a novel opportunity for treatment of CRC, an “old age” disease with an “age old” solution.
PMCID: PMC3693477  PMID: 23814530
nutraceuticals; CRC; curcumin; gingerol; piperine
3.  Development and Validation of a Sensitive LC/MS/MS Method for the Determination of γ-Tocotrienol in Rat Plasma: Application to Pharmacokinetic Studies 
γ-Tocotrienol has attracted great attention due to its multiple health benefits. This study developed and validated a simple, specific, sensitive and reliable LC/MS/MS method to analyze γ-tocotrienol in rat plasma. Plasma samples (50 µL) were extracted with internal standard solution (25 ng/mL of itraconazole) in acetonitrile (200 µL) with an average recovery of 44.7% and an average matrix effect of −2.9%. The separation of γ-tocotrienol and internal standard from the plasma components was achieved with a Waters XTerra® MS C18 column with acetonitrile/water as mobile phases. Analysis was performed under positive ionization electrospray mass spectrometer via the multiple reaction monitoring. The standard curve was linear over a concentration range of 10 – 1000 ng/mL with correlation coefficient values > 0.997. The method was validated with intra- and inter-day accuracy (relative error) ranged from 1.79 to 9.17% and 2.16 to 9.66%, respectively, and precision (coefficient of variation) ranged from 1.94 to 9.25% and 2.37 to 10.08%, respectively. The short-term disability, freeze-thaw stability and the processed sample stability tests were performed. This method was further applied to analyze γ-tocotrienol plasma concentrations in rats at various time points after administration of a 2 mg/kg single intravenous dose, and a pharmacokinetic profile was successfully obtained.
PMCID: PMC3696499  PMID: 22522964
γ-tocotrienol; vitamin E; LC/MS/MS; pharmacokinetics; rat plasma
5.  Ursolic Acid Inhibits Growth and Metastasis of Human Colorectal Cancer in an Orthotopic Nude Mouse Model by Targeting Multiple Cell Signaling Pathways: Chemosensitization with Capecitabine 
Development of chemoresistance, poor prognosis, and metastasis often renders the current treatments for colorectal cancer (CRC) ineffective. Whether ursolic acid (UA), a component of numerous medicinal plants, either alone or in combination with capecitabine, can inhibit the growth and metastasis of human CRC was investigated.
Experimental design
The effect of UA on proliferation of colorectal cancer cell lines was examined by mitochondrial dye-uptake assay, apoptosis by esterase staining, NF-κB activation by DNA binding assay and protein expression by western blot. The effect of UA on the growth and chemosensitization was also examined in orthotopically-implanted CRC in nude mice.
We found that UA inhibited the proliferation of different colon cancer cell lines. This is correlated with inhibition of constitutive NF-κB activation and downregulation of cell survival (Bcl-xL, Bcl-2, cFLIP, survivin), proliferative (Cyclin D1), and metastatic (MMP-9, VEGF, ICAM-1) proteins. When examined in an orthotopic nude-mice model, UA significantly inhibited tumor volume, ascites formation and distant organ metastasis, and this effect was enhanced with capecitabine. Immunohistochemistry of tumor tissue indicated that UA downregulated biomarkers of proliferation (Ki-67) and microvessel density (CD31). This effect was accompanied by suppression of NF-κB, STAT3, and β-catenin. In addition, UA suppressed EGFR, and induced p53, and p21 expression. We also observed bioavailability of UA in the serum and tissue of animals.
Overall our results demonstrate that UA can inhibit the growth and metastasis of CRC and further enhance the therapeutic effects of capecitabine through suppression of multiple biomarkers linked to inflammation, proliferation, invasion, angiogenesis, and metastasis.
PMCID: PMC3677707  PMID: 22832932
6.  Zyflamend Suppresses Growth and Sensitizes Human Pancreatic Tumors to Gemcitabine in an Orthotopic Mouse Model Through Modulation of Multiple Targets 
Agents that can potentiate the efficacy of standard chemotherapy against pancreatic cancer are of great interest. Because of their low cost and safety, patients commonly use a variety of dietary supplements, although evidence of their efficacy is often lacking. One such commonly used food supplement, Zyflamend, is a polyherbal preparation with potent anti-inflammatory activities, and preclinical efficacy against prostate and oral cancer. Whether Zyflamend has any efficacy against human pancreatic cancer alone or in combination with gemcitibine, a commonly used agent, was examined in cell cultures and in an orthotopic mouse model. In vitro, Zyflamend inhibited the proliferation of pancreatic cancer cell lines regardless of p53 status and also enhanced gemcitabine-induced apoptosis. This finding correlated with inhibition of NF-κB activation by Zyflamend and suppression of cyclin D1, c-myc, COX-2, Bcl-2, IAP, survivin, VEGF, ICAM-1, and CXCR4. In nude mice, oral administration of Zyflamend alone significantly inhibited the growth of orthotopically transplanted human pancreatic tumors, and when combined with gemcitabine, further enhanced the antitumor effects. Immunohistochemical and Western blot analyses of tumor tissue showed that the suppression of pancreatic cancer growth correlated with inhibition of proliferation index marker (Ki-67), COX-2, MMP-9, NF-κB, and VEGF. Overall, these results suggest that the concentrated multiherb product Zyflamend alone can inhibit the growth of human pancreatic tumors and, in addition, can sensitize pancreatic cancers to gemcitabine through the suppression of multiple targets linked to tumorigenesis.
PMCID: PMC3288649  PMID: 21935918
Zyflamend; pancreatic cancer; inflammation
7.  Serum sTNFR1, IL6, and the Development of Fatigue in Patients with Gastrointestinal Cancer Undergoing Chemoradiation Therapy 
Brain, Behavior, and Immunity  2012;26(5):699-705.
Although evidence of inflammation and fatigue has been noted in cancer survivors, whether inflammation is linked to the expression of fatigue and other symptoms arising from concurrent chemoradiation therapy (CXRT) has not been well studied. Patients undergoing CXRT for locally advanced colorectal or esophageal cancer (n = 103) reported multiple symptoms weekly via the M. D. Anderson Symptom Inventory (MDASI) from start of therapy. Serum samples were collected weekly to examine changes in inflammatory markers (interleukin [IL]-6, IL-8, IL-10, IL-1 receptor antagonist [IL-1RA], vascular endothelial growth factor [VEGF], and soluble receptor 1 for tumor necrosis factor [sTNF-R1]) via enzyme-linked immunosorbent assay. Relationships between symptom severity and inflammatory-marker concentration levels were estimated using mixed-effect regression analysis, controlled for week of therapy, age, sex, body mass index, pre-CXRT tumor stage, pre-CXRT chemotherapy, pre-CXRT statin use, and type of cancer. Fatigue was the most severe symptom over time, its development profile shared with pain, distress, drowsiness, poor appetite, and disturbed sleep. sTNF-R1 and IL-6 shared a similar pattern of symptom development, with significant increase during CXRT and decrease after completion of CXRT. Serum concentrations of sTNF-R1 were positively associated over time with the severity of fatigue (p = .00097), while sTNF-R1 and IL-6 were positively related to the severity of a component score of the six most severe symptoms (both p < .0001). This longitudinal study suggests a role for over-expressed sTNF-R1 and IL-6 in the development of fatigue and other severe sickness symptoms during CXRT in patients with colorectal or esophageal cancer.
PMCID: PMC3355215  PMID: 22251605
fatigue; symptoms; sickness behavior; cytokines; cancer; inflammation; MDASI; chemoradiation
8.  Neoadjuvant Treatment Response As an Early Response Indicator for Patients With Rectal Cancer 
Journal of Clinical Oncology  2012;30(15):1770-1776.
Neoadjuvant chemoradiotherapy for rectal cancer is associated with improved local control and may result in complete tumor response. Associations between tumor response and disease control following radical resection should be established before tumor response is used to evaluate treatment strategies. The purpose of this study was to assess and compare oncologic outcomes associated with the degree of pathologic response after chemoradiotherapy.
Patients and Methods
All patients with locally advanced (cT3-4 or cN+ by endorectal ultrasonography, computed tomography, or magnetic resonance imaging) rectal carcinoma diagnosed from 1993 to 2008 at our institution and treated with preoperative chemoradiotherapy and radical resection were identified, and their records were retrospectively reviewed. The median radiation dose was 50.4 Gy with concurrent chemotherapy. Recurrence-free survival (RFS), distant metastasis (DM), and local recurrence (LR) rates were compared among patients with complete (ypT0N0), intermediate (ypT1-2N0), or poor (ypT3-4 or N+) response by using Kaplan-Meier survival analysis and multivariate Cox proportional hazards regression.
In all, 725 patients were classified by tumor response: complete (131; 18.1%), intermediate (210; 29.0%), and poor (384; 53.0%). Age, sex, cN stage, and tumor location were not related to tumor response. Tumor response (complete v intermediate v poor) was associated with 5-year RFS (90.5% v 78.7% v 58.5%; P < .001), 5-year DM rates (7.0% v 10.1% v 26.5%; P < .001), and 5-year LR only rates (0% v 1.4% v 4.4%; P = .002).
Treatment response to neoadjuvant chemoradiotherapy among patients with locally advanced rectal cancer undergoing radical resection is an early surrogate marker and correlate to oncologic outcomes. These data provide guidance with response-stratified oncologic benchmarks for comparisons of novel treatment strategies.
PMCID: PMC3383178  PMID: 22493423
9.  Boswellic Acid Inhibits Growth and Metastasis of Human Colorectal Cancer in Orthotopic Mouse Model By Downregulating Inflammatory, Proliferative, Invasive, and Angiogenic Biomarkers 
Numerous cancer therapeutics were originally identified from natural products used in traditional medicine. One such agent is acetyl-11-keto-beta-boswellic acid (AKBA), derived from the gum resin of the Boswellia serrata known as Salai guggal or Indian frankincense. Traditionally it has been used in Ayurvedic medicine to treat proinflammatory conditions. In the present report, we hypothesized that AKBA can affect the growth and metastasis of colorectal cancer (CRC) in orthotopically-implanted tumors in nude mice. We found that the oral administration of AKBA (50-200 mg/kg) dose-dependently inhibited the growth of CRC tumors in mice, resulting in decrease in tumor volumes than those seen in vehicle-treated mice without significant decreases in body weight. In addition, we observed that AKBA was highly effective in suppressing ascites and distant metastasis to the liver, lungs, and spleen in orthotopically-implanted tumors in nude mice. When examined for the mechanism, we found that markers of tumor proliferation index Ki-67 and the microvessel density CD31; were significantly downregulated by AKBA treatment. We also found that AKBA significantly suppressed NF-κB activation in the tumor tissue and expression of pro-inflammatory (COX2), tumor survival (bcl-2, bcl-xL, IAP-1, survivin), proliferative (cyclin D1), invasive (ICAM-1, MMP-9) and angiogenic (CXCR4 and VEGF) biomarkers. When examined for serum and tissue levels of AKBA, a dose-dependent increase in the levels of the drug was detected, indicating its bioavailability. Thus, our findings suggest that this boswellic acid analogue can inhibit the growth and metastasis of human CRC in vivo through downregulation of cancer-associated biomarkers.
PMCID: PMC3246525  PMID: 21702037
AKBA; colorectal cancer; NF-κB; growth; metastasis
10.  Metformin use and improved response to therapy in rectal cancer 
Cancer Medicine  2013;2(1):99-107.
Locally advanced rectal cancer is commonly treated with chemoradiation prior to total mesorectal excision (TME). Studies suggest that metformin may be an effective chemopreventive agent in this disease as well as a possible adjunct to current therapy. In this study, we examined the effect of metformin use on pathologic complete response (pCR) rates and outcomes in rectal cancer. The charts of 482 patients with locally advanced rectal adenocarcinoma treated from 1996 to 2009 with chemoradiation and TME were reviewed. Median radiation dose was 50.4 Gy (range 19.8–63). Nearly, all patients were treated with concurrent 5-fluorouracil-based chemotherapy (98%) followed by adjuvant chemotherapy (81.3%). Patients were categorized as nondiabetic (422), diabetic not taking metformin (40), or diabetic taking metformin (20). No significant differences between groups were found in clinical tumor classification, nodal classification, tumor distance from the anal verge or circumferential extent, pretreatment carcinoembryonic antigen level, or pathologic differentiation. pCR rates were 16.6% for nondiabetics, 7.5% for diabetics not using metformin, and 35% for diabetics taking metformin, with metformin users having significantly higher pCR rates than either nondiabetics (P = 0.03) or diabetics not using metformin (P = 0.007). Metformin use was significantly associated with pCR rate on univariate (P = 0.05) and multivariate (P = 0.01) analyses. Furthermore, patients taking metformin had significantly increased disease-free (P = 0.013) and overall survival (P = 0.008) compared with other diabetic patients. Metformin use is associated with significantly higher pCR rates as well as improved survival. These promising data warrant further prospective study.
PMCID: PMC3797563  PMID: 24133632
Chemotherapy; metformin; radiation; rectal cancer
11.  Clinical and Prognostic Implications of Plasma Insulin-Like Growth Factor-1 and Vascular Endothelial Growth Factor in Patients With Hepatocellular Carcinoma 
Journal of Clinical Oncology  2011;29(29):3892-3899.
Cirrhosis and hepatocellular carcinoma (HCC) together form a two-disease state that affects survival of patients with HCC and dictates treatment decisions and prognostic stratification of patients in clinical trials. The study objective was to improve prognostic stratification of patients with HCC.
Patients and Methods
We prospectively collected plasma samples and baseline clinicopathologic features from 288 new patients with HCC, and plasma insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) levels were tested. We applied Cox regression and log-rank tests to assess association of IGF-1 and VEGF with overall survival (OS), Kaplan-Meier curves to estimate OS, and recursive partitioning to determine optimal cutoff points for IGF-1 and VEGF. Prognostic ability of conventional and molecular Barcelona Clinic Liver Cancer classifications was compared using the c-index.
Lower plasma IGF-1 and higher plasma VEGF levels significantly correlated with advanced clinicopathologic parameters and poor OS, with optimal cut points of 26 ng/mL and 450 pg/mL, respectively. The combination of low IGF-1 and high VEGF predicted median OS of 2.7 months compared with 19 months for patients with high IGF-1 and low VEGF (P < .001), further refining the prognostic ability of conventional HCC staging (P < .001).
Baseline levels of plasma IGF-1 and VEGF correlated significantly with survival in patients with HCC. Integrating IGF-1 and VEGF into HCC staging significantly enhanced prognostic stratification of patients. If validated, these results may prove to be useful in designing strategies to personalize management approaches among these patients.
PMCID: PMC3189091  PMID: 21911725
12.  Charged Particle Therapy for Hepatocellular Carcinoma 
Seminars in radiation oncology  2011;21(4):278-286.
Historically, the use of external beam radiotherapy for hepatocellular carcinoma (HCC) has been limited by toxicity to the uninvolved liver and surrounding structures. Advances in photon radiotherapy have improved dose conformality to the tumor and facilitated dose escalation, a key contributor to improved HCC radiation treatment outcomes. However, despite these advances in photon radiotherapy, significant volumes of liver still receive low doses of radiation that can preclude dose escalation, particularly in patients with limited functional liver reserves. By capitalizing on the lack of exit dose along the beam path beyond the tumor and higher biological effectiveness, charged particle therapy offers the promise of maximizing tumor control via dose escalation without excessive liver toxicity. In this review we discuss the distinctive biophysical attributes of both proton and carbon ion radiotherapy, particularly as they pertain to treatment of HCC. We also review the available literature regarding clinical outcomes and toxicity of using charged particles for the treatment of HCC.
PMCID: PMC3230301  PMID: 21939857
13.  Phase II Trial of Cetuximab, Gemcitabine, and Oxaliplatin Followed by Chemoradiation With Cetuximab for Locally Advanced (T4) Pancreatic Adenocarcinoma: Correlation of Smad4(Dpc4) Immunostaining With Pattern of Disease Progression 
Journal of Clinical Oncology  2011;29(22):3037-3043.
This phase II trial was designed to assess the efficacy and safety of cetuximab, gemcitabine, and oxaliplatin followed by cetuximab, capecitabine, and radiation therapy in locally advanced pancreatic cancer (LAPC).
Patients and Methods
Treatment-naive eligible patients (n = 69) received intravenous gemcitabine (1,000 mg/m2) and oxaliplatin (100 mg/m2) every 2 weeks for four doses, followed by radiation (50.4 Gy to the gross tumor only) with concurrent capecitabine (825 mg/m2 twice daily on radiation treatment days). Cetuximab (500 mg/m2) was started on day 1 of chemotherapy and was continued every 2 weeks during chemotherapy and chemoradiotherapy. Diagnostic cytology specimens were immunostained for Smad4(Dpc4) expression.
Median overall survival time was 19.2 months (95% CI, 14.2 to 24.2 months), and 1-year, 2-year, and 4-year actuarial overall survival rates were 66.0%, 25.02%, and 11.3%, respectively. Acneiform rash correlated with improved survival (P = .001), but initial CA19-9, borderline resectable initial stage, and surgical resection (n = 7) did not. The 1-year and 2-year radiographic local progression rates were 22.8% and 61.0%, respectively. The worst acute toxic effects were GI toxicity (32% and 10% for grades 2 and 3, respectively); fatigue (26% and 6% for grades 2 and 3, respectively); sensory neuropathy (9% and 1% for grades 2 and 3, respectively); and acneiform rash (54% and 3% for grades 2 and 3, respectively). Smad4(Dpc4) expression correlated with a local rather than a distant dominant pattern of disease progression (P = .016).
This regimen appears effective and has acceptable toxicity. The primary end point (1-year overall survival rate > 45%) was met, with encouraging survival duration. Smad4(Dpc4) immunostaining correlated with the pattern of disease progression. Prospective validation of Smad4(Dpc4) expression in cytology specimens as a predictive biomarker is warranted and may lead to personalized treatment strategies for patients with localized pancreatic cancer.
PMCID: PMC3157965  PMID: 21709185
14.  Nanoparticle-mediated hyperthermia in cancer therapy 
Therapeutic delivery  2011;2(8):1001-1014.
A small rise in tumor temperature (hyperthermia) makes cancer cells more susceptible to radiation and chemotherapy. The means of achieving this is not trivial, and traditional methods have certain drawbacks. Loading tumors with systematically asministered energy-transducing nanoparticles can circumvent several of the obstacles to achieve tumor hyperthermia. However, nanoparticles also face unique challenges prior to clinical implementation. This article summarizes the state-of-the-art current technology and discusses the advantages and challenges of the three major nanoparticle formulations in focus: gold nanoshells and nanorods, superparamagnetic iron oxide particles and carbon nanotubes.
PMCID: PMC3323111  PMID: 22506095
16.  A mouse model for triple-negative breast cancer tumor-initiating cells (TNBC-TICs) exhibits similar aggressive phenotype to the human disease 
BMC Cancer  2012;12:120.
Triple-negative breast cancer (TNBC) exhibit characteristics quite distinct from other kinds of breast cancer, presenting as an aggressive disease--recurring and metastasizing more often than other kinds of breast cancer, without tumor-specific treatment options and accounts for 15% of all types of breast cancer with higher percentages in premenopausal African-American and Hispanic women. The reason for this aggressive phenotype is currently the focus of intensive research. However, progress is hampered by the lack of suitable TNBC cell model systems.
To understand the mechanistic basis for the aggressiveness of TNBC, we produced a stable TNBC cell line by sorting for 4T1 cells that do not express the estrogen receptor (ER), progesterone receptor (PgR) or the gene for human epidermal growth factor receptor 2 (HER2). As a control, we produced a stable triple-positive breast cancer (TPBC) cell line by transfecting 4T1 cells with rat HER2, ER and PgR genes and sorted for cells with high expression of ER and PgR by flow cytometry and high expression of the HER2 gene by Western blot analysis.
We isolated tumor-initiating cells (TICs) by sorting for CD24+/CD44high/ALDH1+ cells from TNBC (TNBC-TICs) and TPBC (TPBC-TICs) stable cell lines. Limiting dilution transplantation experiments revealed that CD24+/CD44high/ALDH1+ cells derived from TNBC (TNBC-TICs) and TPBC (TPBC-TICs) were significantly more effective at repopulating the mammary glands of naïve female BALB/c mice than CD24-/CD44-/ALDH1- cells. Implantation of the TNBC-TICs resulted in significantly larger tumors, which metastasized to the lungs to a significantly greater extent than TNBC, TPBC-TICs, TPBC or parental 4T1 cells. We further demonstrated that the increased aggressiveness of TNBC-TICs correlates with the presence of high levels of mouse twenty-five kDa heat shock protein (Hsp25/mouse HspB1) and seventy-two kDa heat shock protein (Hsp72/HspA1A).
Taken together, we have developed a TNBC-TICs model system based on the 4T1 cells which is a very useful metastasis model with the advantage of being able to be transplanted into immune competent recipients. Our data demonstrates that the TNBC-TICs model system could be a useful tool for studies on the pathogenesis and therapeutic treatment for TNBC.
PMCID: PMC3340297  PMID: 22452810
Triple-negative breast cancer; Mouse and human HspB1; Hsp25; Hsp27; Hsp72/HspA1A; Heat shock; Cancer stem cells; Tumor-initiating cells
17.  In vivo tumor targeting of gold nanoparticles: effect of particle type and dosing strategy 
Gold nanoparticles (GNPs) have gained significant interest as nanovectors for combined imaging and photothermal therapy of tumors. Delivered systemically, GNPs preferentially accumulate at the tumor site via the enhanced permeability and retention effect, and when irradiated with near infrared light, produce sufficient heat to treat tumor tissue. The efficacy of this process strongly depends on the targeting ability of the GNPs, which is a function of the particle’s geometric properties (eg, size) and dosing strategy (eg, number and amount of injections). The purpose of this study was to investigate the effect of GNP type and dosing strategy on in vivo tumor targeting. Specifically, we investigated the in vivo tumor-targeting efficiency of pegylated gold nanoshells (GNSs) and gold nanorods (GNRs) for single and multiple dosing. We used Swiss nu/nu mice with a subcutaneous tumor xenograft model that received intravenous administration for a single and multiple doses of GNS and GNR. We performed neutron activation analysis to quantify the gold present in the tumor and liver. We performed histology to determine if there was acute toxicity as a result of multiple dosing. Neutron activation analysis results showed that the smaller GNRs accumulated in higher concentrations in the tumor compared to the larger GNSs. We observed a significant increase in GNS and GNR accumulation in the liver for higher doses. However, multiple doses increased targeting efficiency with minimal effect beyond three doses of GNPs. These results suggest a significant effect of particle type and multiple doses on increasing particle accumulation and on tumor targeting ability.
PMCID: PMC3299576  PMID: 22419872
gold nanorods; gold nanoshells; tumor targeting; multiple dosing
18.  HIF-1 Dependent Stromal Adaptation to Ischemia Mediates In Vivo Tumor Radiation Resistance 
Molecular cancer research : MCR  2011;9(3):259-270.
Hypoxia inducible factor (HIF)-1 promotes cancer cell survival and tumor progression. The specific role played by HIF-1 and tumor-stromal interactions towards determining tumor resistance to radiation treatment remains undefined. We applied a multi-modality preclinical imaging platform to mechanistically characterize tumor response to radiation, with a focus on HIF-1 dependent resistance pathways.
C6 glioma and HN5 human squamous carcinoma cells were stably transfected with a dual HIF-1 signaling reporter construct (dxHRE-tk/eGFP-cmvRed2XPRT). Reporter cells were serially interrogated in vitro before and after irradiation as monolayer and multicellular spheroid cultures, and as subcutaneous xenografts in nu/nu mice.
In vitro, single-dose irradiation of C6 and HN5 reporter cells modestly impacted HIF-1 signaling in normoxic monolayers and inhibited HIF-1 signaling in maturing spheroids. In contrast, irradiation of C6 or HN5 reporter xenografts with 8 Gy in vivo elicited marked upregulation of HIF-1 signaling and downstream pro-angiogenic signaling at 48 hours which preceded recovery of tumor growth. In situ ultrasound and dynamic contrast enhanced (DCE)-MRI indicated that HIF-1 signaling followed acute disruption of stromal vascular function. High-resolution PET and dual-contrast DCE-MRI imaging of immobilized dorsal skin window tumors confirmed post-radiotherapy HIF-1 signaling to spatio-temporally coincide with impaired stromal vascular function. Targeted disruption of HIF-1 signaling established this pathway to be a determinant of tumor radioresistance.
Our results illustrate that tumor radioresistance is mediated by a capacity to compensate for stromal vascular disruption through HIF-1 dependent pro-angiogenic signaling, and that clinically relevant vascular imaging techniques can spatially define mechanisms associated with tumor irradiation.
PMCID: PMC3077053  PMID: 21364021
Hypoxia; HIF-1; Radiation; Tumor Microenvironment; Imaging; Treatment Response; Stromal Adaptation
19.  Recurrent invasive lobular carcinoma presenting as a ruptured breast implant 
Radiology and Oncology  2011;46(1):23-27.
For years, the treatment for invasive lobular carcinoma (ILC) has been mastectomy secondary to the lack of studies investigating the efficacy of breast conservation therapy on patients afflicted with ILC and due to the lack of long-term follow up investigating locoregional recurrence in this patient population. In this article we report the clinical course of a patient diagnosed with ILC.
Case report
We describe the case of a 50-year-old woman with stage IIB (T2N1M0) ER/PR positive right breast ILC who underwent a right modified radical mastectomy, postoperative chemotherapy, a prophylactic left simple mastectomy with bilateral breast reconstruction and tamoxifen. Approximately 12 years later, she presented with a deflated breast implant and recurrent breast cancer with metastatic spread. She received palliative radiotherapy then palliative chemotherapy. Unfortunately, she succumbed to the cancer less than a year after being diagnosed with metastatic disease.
This may be the first case report of a ruptured breast implant presenting at the same time as the diagnosis of recurrent breast cancer.
PMCID: PMC3423769  PMID: 22933976
breast cancer; invasive lobular carcinoma; breast implant; rupture
20.  Number of Lymph Nodes Examined and Prognosis Among Pathologically Lymph Node-Negative Patients After Preoperative Chemoradiation Therapy for Rectal Adenocarcinoma 
Cancer  2011;117(16):3713-3722.
Preoperative chemoradiation for rectal cancer can decrease the number of evaluable lymph nodes. Hence, the prognostic role of lymph node evaluation in patients with rectal cancer who receive preoperative chemoradiation is unclear. The authors of this report evaluated the prognostic impact of the number of lymph nodes examined in patients with rectal cancer who had negative lymph nodes based on the pathologic extent of disease (ypN0) after they received preoperative chemoradiation.
Between 1990 and 2004, 372 patients with nonmetastatic rectal adenocarcinoma received preoperative chemoradiation followed by mesorectal excision and had ypN0 disease. The median radiation dose was 45 gray, and 68% of patients received adjuvant chemotherapy.
Patients had a median of 7 lymph nodes examined after preoperative chemoradiation. Compared with patients who had ≤7 lymph nodes examined, patients who had >7 lymph nodes had higher 5-year rates of freedom from relapse (86% vs 72%; log-rank P = .005) and cancer-specific survival (95% vs 86%; log-rank P = .0004), but no significant difference was observed in the overall survival rate (87% vs 81%; log-rank P = .07). Multivariate Cox proportional models demonstrated that patients who had >7 lymph nodes examined had a significantly lower risk of relapse (hazard ratio [HR], 0.39; P = .003) and death from rectal cancer (HR, 0.45; P = .04) but a similar risk of all-cause mortality (HR, 0.75; 95% CI, 0.46–1.20; P = .23) compared with patients who had ≤7 lymph nodes examined.
The number of lymph nodes examined was associated independently with disease relapse and cancer-specific survival in patients with rectal cancer who had ypN0 disease after receiving preoperative chemoradiation. Hence, the authors concluded that the number of negative lymph nodes examined may be a prognostic factor in patients with rectal cancer who receive preoperative chemoradiation.
PMCID: PMC3266661  PMID: 21328329
rectal cancer; prognostic factors; radiation therapy; lymph nodes
21.  Inhibition of radiation-induced DNA repair and pro-survival pathways contribute to vorinostat-mediated radiosensitization of pancreatic cancer cells 
Pancreas  2010;39(8):1277-1283.
The intrinsic radioresistance of pancreatic cancer (PaCa) is due to multiple oncogenic signaling pathways. In contrast to combining radiation therapy (RT) with targeted therapeutic agent(s) whose blockade can be circumvented by redundant signaling pathways, we evaluated the combination of RT with a broad-spectrum histone deacetylase inhibitor, vorinostat.
Radiosensitization by vorinostat was analyzed using clonogenic survival assays. Apoptosis was evaluated using flow cytometry and immunoblotting. DNA repair was evaluated using immunofluorescence assessment of histone2AX phosphorylation and immunoblotting for DNA repair proteins. Pro-survival pathway proteins were measured by immunoblotting and electrophoretic mobility shift assays.
Vorinostat significantly sensitized PaCa cells to radiation, but vorinostat-induced apoptosis did not contribute significantly to the observed radiosensitization. However, vorinostat inhibited DNA damage repair by targeting key DNA repair proteins and also abrogated pro-survival pathways responsible for PaCa aggressiveness and radioresistance. Specifically, the constitutively overexpressed epidermal growth factor receptor and nuclear factor kappaB pathways were shown to be induced by radiation and inhibited by vorinostat.
Vorinostat augments the anti-tumor effects of RT by abrogating radioresistance responses of PaCa cells mediated by pro-survival and DNA repair pathways, and promises to be a clinically relevant adjunct to RT for treatment of PaCa.
PMCID: PMC2955787  PMID: 20531243
Vorinostat; Pancreatic Cancer; Radiation; NF-κB; EGFR; Radiosensitization
22.  γ-Tocotrienol Inhibits Pancreatic Tumors and Sensitizes Them to Gemcitabine Treatment by Modulating the Inflammatory Microenvironment 
Cancer research  2010;70(21):8695-8705.
Pancreatic cancers generally respond poorly to chemotherapy, prompting a need to identify agents that could sensitize tumors to treatment. In this study, we investigated the response of human pancreatic cells to gamma-tocotrienol (γ-T3), a novel, unsaturated form of vitamin E found in palm oil and rice bran oil, to determine whether it could potentiate the effects of gemcitabine, a standard of care in clinical treatment of pancreatic cancer. γ-T3 inhibited the in vitro proliferation of pancreatic cancer cell lines with variable p53 status and potentiated gemcitabine-induced apoptosis. These effects correlated with an inhibition of NF-κB activation by γ-T3 and a suppression of key cellular regulators including cyclin D1, c-Myc, COX-2, Bcl-2, cIAP, survivin, VEGF, ICAM-1, and CXCR4. In an orthotopic nude mouse model of human pancreatic cancer, oral administration of γ-T3 inhibited tumor growth and enhanced the antitumor properties of gemcitabine. Immunohistochemical analysis indicated a correlation between tumor growth inhibition and reduced expression of Ki-67, COX-2, MMP-9, NF-κB p65 and VEGF in the tissue. Combination treatment also downregulated NF-κB activity along with the NF-κB-regulated gene products cyclin D1, c-Myc, VEGF, MMP-9, CXCR4. Consistent with an enhancement of tumor apoptosis caspase activation was observed in tumor tissues. Overall, Our findings suggest that γ-T3 can inhibit the growth of human pancreatic tumors and sensitize them to gemcitabine by suppressing of NF-κB-mediated inflammatory pathways linked to tumorigenesis.
PMCID: PMC2970705  PMID: 20864511
tocotrienol; pancreatic cancer; NF-κB; inflammation
23.  Combined Hyperthermia and Radiotherapy for the Treatment of Cancer 
Cancers  2011;3(4):3799-3823.
Radiotherapy is used to treat approximately 50% of all cancer patients, with varying success. Radiation therapy has become an integral part of modern treatment strategies for many types of cancer in recent decades, but is associated with a risk of long-term adverse effects. Of these side effects, cardiac complications are particularly relevant since they not only adversely affect quality of life but can also be potentially life-threatening. The dose of ionizing radiation that can be given to the tumor is determined by the sensitivity of the surrounding normal tissues. Strategies to improve radiotherapy therefore aim to increase the effect on the tumor or to decrease the effects on normal tissues, which must be achieved without sensitizing the normal tissues in the first approach and without protecting the tumor in the second approach. Hyperthermia is a potent sensitizer of cell killing by ionizing radiation (IR), which can be attributed to the fact that heat is a pleiotropic damaging agent, affecting multiple cell components to varying degrees by altering protein structures, thus influencing the DNA damage response. Hyperthermia induces heat shock protein 70 (Hsp70; HSPA1A) synthesis and enhances telomerase activity. HSPA1A expression is associated with radioresistance. Inactivation of HSPA1A and telomerase increases residual DNA DSBs post IR exposure, which correlates with increased cell killing, supporting the role of HSPA1A and telomerase in IR-induced DNA damage repair. Thus, hyperthermia influences several molecular parameters involved in sensitizing tumor cells to radiation and can enhance the potential of targeted radiotherapy. Therapy-inducible vectors are useful for conditional expression of therapeutic genes in gene therapy, which is based on the control of gene expression by conventional treatment modalities. The understanding of the molecular response of cells and tissues to ionizing radiation has lead to a new appreciation of the exploitable genetic alterations in tumors and the development of treatments combining pharmacological interventions with ionizing radiation that more specifically target either tumor or normal tissue, leading to improvements in efficacy.
PMCID: PMC3763397  PMID: 24213112
heat shock proteins; radiotherapy; hyperthermia; cancer; hypoxia
24.  Intra-organ Biodistribution of Gold Nanoparticles Using Intrinsic Two-photon Induced Photoluminescence 
Lasers in surgery and medicine  2010;42(7):630-639.
Background and Objectives
Gold nanoparticles (GNPs) such as gold nanoshells (GNSs) and gold nanorods (GNRs) have been explored in a number of in vitro and in vivo studies as imaging contrast and cancer therapy agents due to their highly desirable spectral and molecular properties. While the organ-level biodistribution of these particles has been reported previously, little is known about the cellular level or intra-organ biodistribution. The objective of this study was to demonstrate the use of intrinsic two-photon induced photoluminescence (TPIP) to study the cellular level biodistribution of GNPs.
Study Design/Materials and Methods
Tumor xenografts were created in twenty-seven male nude mice (Swiss nu/nu) using HCT 116 cells (CCL-247, ATCC, human colorectal cancer cell line). GNSs and GNRs were systemically injected 24 hr. prior to tumor harvesting. A skin flap with the tumor was excised and sectioned as 8 μm thick tissues for imaging GNPs under a custom-built multiphoton microscope. For multiplexed imaging, nuclei, cytoplasm, and blood vessels were demonstrated by hematoxylin and eosin (H&E) staining, YOYO-1 iodide staining and CD31-immunofluorescence staining.
Distribution features of GNPs at the tumor site were determined from TPIP images. GNSs and GNRs had a heterogeneous distribution with higher accumulation at the tumor cortex than tumor core. GNPs were also observed in unique patterns surrounding the perivascular region. While most GNSs were confined at the distance of approximately 400 μm inside the tumor edge, GNRs were shown up to 1.5 mm penetration inside the edge.
We have demonstrated the use of TPIP imaging in a multiplexed fashion to image both GNPs and nuclei, cytoplasm, or vasculature simultaneously. We also confirmed that TPIP imaging enabled visualization of GNP distribution patterns within the tumor and other critical organs. These results suggest that direct luminescence-based imaging of metal nanoparticles holds a valuable and promising position in understanding the accumulation kinetics of GNPs. In addition, these techniques will be increasingly important as the use of these particles progress to human clinical trials where standard histopathology techniques are used to analyze their effects.
PMCID: PMC3052865  PMID: 21399728
gold nanoshell; gold nanorod; two-photon induced photoluminescence
25.  Intensity modulated radiation therapy (IMRT): differences in target volumes and improvement in clinically relevant doses to small bowel in rectal carcinoma 
A strong dose-volume relationship exists between the amount of small bowel receiving low- to intermediate-doses of radiation and the rates of acute, severe gastrointestinal toxicity, principally diarrhea. There is considerable interest in the application of highly conformal treatment approaches, such as intensity-modulated radiation therapy (IMRT), to reduce dose to adjacent organs-at-risk in the treatment of carcinoma of the rectum. Therefore, we performed a comprehensive dosimetric evaluation of IMRT compared to 3-dimensional conformal radiation therapy (3DCRT) in standard, preoperative treatment for rectal cancer.
Using RTOG consensus anorectal contouring guidelines, treatment volumes were generated for ten patients treated preoperatively at our institution for rectal carcinoma, with IMRT plans compared to plans derived from classic anatomic landmarks, as well as 3DCRT plans treating the RTOG consensus volume. The patients were all T3, were node-negative (N = 1) or node-positive (N = 9), and were planned to a total dose of 45-Gy. Pairwise comparisons were made between IMRT and 3DCRT plans with respect to dose-volume histogram parameters.
IMRT plans had superior PTV coverage, dose homogeneity, and conformality in treatment of the gross disease and at-risk nodal volume, in comparison to 3DCRT. Additionally, in comparison to the 3DCRT plans, IMRT achieved a concomitant reduction in doses to the bowel (small bowel mean dose: 18.6-Gy IMRT versus 25.2-Gy 3DCRT; p = 0.005), bladder (V40Gy: 56.8% IMRT versus 75.4% 3DCRT; p = 0.005), pelvic bones (V40Gy: 47.0% IMRT versus 56.9% 3DCRT; p = 0.005), and femoral heads (V40Gy: 3.4% IMRT versus 9.1% 3DCRT; p = 0.005), with an improvement in absolute volumes of small bowel receiving dose levels known to induce clinically-relevant acute toxicity (small bowel V15Gy: 138-cc IMRT versus 157-cc 3DCRT; p = 0.005). We found that the IMRT treatment volumes were typically larger than that covered by classic bony landmark-derived fields, without incurring penalty with respect to adjacent organs-at-risk.
For rectal carcinoma, IMRT, compared to 3DCRT, yielded plans superior with respect to target coverage, homogeneity, and conformality, while lowering dose to adjacent organs-at-risk. This is achieved despite treating larger volumes, raising the possibility of a clinically-relevant improvement in the therapeutic ratio through the use of IMRT with a belly-board apparatus.
PMCID: PMC3121606  PMID: 21651775

Results 1-25 (54)