Vasundara Venkateswaran

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Prospective Multi-Institutional Study Evaluating the Performance of Prostate Cancer Risk Calculators

PURPOSE Prostate cancer risk calculators incorporate many factors to evaluate an individuals risk for prostate cancer. We validated two common North American-based, prostate cancer risk calculators. PATIENTS AND METHODS We conducted a prospective, multi-institutional study of 2,130 patients who underwent a prostate biopsy for prostate cancer detection from five centers. We evaluated the performance of the Sunnybrook nomogram-based prostate cancer risk calculator (SRC) and the Prostate Cancer Prevention Trial (PCPT) -based risk calculator (PRC) to predict the presence of any cancer and high-grade cancer. We examined discrimination, calibration, and decision curve analysis techniques to evaluate the prediction models. RESULTS Of the 2,130 patients, 867 men (40.7%) were found to have cancer, and 1,263 (59.3%) did not have cancer. Of the patients with cancer, 403 (46.5%) had a Gleason score of 7 or more. The area under the [concentration-time] curve (AUC) for the SRC was 0.67 (95% CI, 0.65 to 0.69); the AUC for the PRC was 0.61 (95% CI, 0.59 to 0.64). The AUC was higher for predicting aggressive disease from the SRC (0.72; 95% CI, 0.70 to 0.75) compared with that from the PRC (0.67; 95% CI, 0.64 to 0.70). Decision curve analyses showed that the SRC performed better than the PRC for risk thresholds of more than 30% for any cancer and more than 15% for aggressive cancer. CONCLUSION The SRC performed better than the PRC, but neither one added clinical benefit for risk thresholds of less than 30%. Further research is needed to improve the AUCs of the risk calculators, particularly for higher-grade cancer.

Abstract 239: Capsaicin may reduce the metastatic burden in the transgenic adenocarcioma of the mouse prostate (TRAMP) model

Introduction and Objective: A large body of evidence supports the role of dietary factors in prostate cancer development and progression. We are interested in investigating the chemopreventive potential of capsaicin, the active compound in chilli peppers that is traditionally used topically to treat various pain-related syndromes. Recently capsaicin has been demonstrated to have anti-carcinogenic properties in vitro through a number of different mechanisms. In our study we aim to study the chemopreventive properties of capsaicin using the transgenic adenocarcinoma of the mouse prostate (TRAMP) model, a murine model that closely resembles the progression of human disease. Methodology: Thirty-five six-week old TRAMP x C57Bk mice were randomized into two groups: control or capsaicin. Mice received either capsaicin (5 mg/kg body weight) or vehicle (saline) three times a week by oral gavage until the age of 30 weeks. Body weight was measured thrice weekly. All mice were sacrificed at 30 weeks. Body weight, genito-urinary (GU) weight, tumour burden were assessed. Prostate, seminal vesicles, lung, liver, esophagus, lymph nodes and pancreas were obtained for histological analysis. Serum was collected at the termination of the study for analysis of serum capsaicin concentration. Prostate tumours were analyzed by immunohistochemical analysis using proliferative and mechanistic markers. All tumours were scored by an on-site pathologist according to the histopathic grading scale described by Hurwitz AA, et al. Results: Interim results revealed that higher percentage of high-grade cancer in control group (n = 18). The presence of PIN-like pre-cancerous lesions in only the treatment group and not the control group (n = 18). The capsaicin treated mice also demonstrated a reduced proportion of metastatic cancers compared to the control group. There were no significant changes in the GU wet weight between groups (n = 35). Immunohistochemical analysis of the prostate tumour is ongoing. Capsaicin was well tolerated, as there was no pathological liver or esophagus or gastrointestinal toxicities or difference in body weight between groups. Further results are currently under investigation. Conclusion: Interim results suggest that oral administration of capsaicin is well tolerated and may reduce the metastatic burden in the TRAMP model. Ongoing studies are currently underway to delineate the mechanism of action. Citation Format: Natalie A. Venier, Toshihiro Yamamoto, Linda Sugar, Neil Fleshner, Laurence Klotz, Vasundara Venkateswaran. Capsaicin may reduce the metastatic burden in the transgenic adenocarcioma of the mouse prostate (TRAMP) model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 239. doi:10.1158/1538-7445.AM2014-239

Abstract 1449: Spicing up radiation treatment for prostate cancer

Introduction and Objective: Radio-sensitizing agents sensitize cells to the lethal effects of ionizing radiation (IR). This permits use of lower doses of radiation to achieve equivalent cancer control thereby minimizing adverse effects to normal tissues. Given their lack of toxicity compounds occurring naturally in the diet make ideal potential radio-sensitizing agents. Capsaicin is the active compound chilli peppers. Traditionally capsaicin is used to treat chronic pain syndromes; however, recently evidence using in vitro prostate cancer (PCa) models describes its anti-carcinogenic potential. In our preliminary studies we have demonstrated the radio-sensitizing capacity of in PCa cells in vitro. Cells treated with capsaicin and/or IR to have increased expression of pro-apoptotic tumour-suppressor proteins p21 and p27 and reduced androgen-receptor. The objective of the present study is to assess the radio-sensitizing capacity in an in vivo model. Methods: Athymic nude mice were inoculated subcutaneously with human PCa (LNCaP) cells. Once xenografts reach 100mm3 forty animals will be randomized into 4 groups (15 /group); control (no treatment), capsaicin alone, ionizing radiation (IR) alone and capsaicin and IR. Treatments were administered over a two-week time period. Capsaicin (5 mg/kg/d) or vehicle was administered 3/week by gavage. RT will be delivered to animals in sterile cages as one fraction (6 Gray). Control animals were mock irradiated. Tumours were measured thrice weekly and volumes were calculated. Tumours were fixed and stained for pathological analyses and immunohistochemical evaluation. Results: There were no differences in food consumption or body weight of mice between groups. Two mice experienced mild to moderate inflammation of the stomach. No other toxicities were observed. Mice treated with capsaicin or IR alone had a significant reduction in tumour growth overtime (p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1449. doi:1538-7445.AM2012-1449

Abstract 2493: Capsaicin, a novel radiosensitizer, acts via a TRPV6 mediated mechanism

Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL Radiosensitizing agents sensitize cells to the lethal effects of ionizing radiation (IR). This permits use of lower doses of radiation to achieve equivalent cancer control thereby minimizing adverse effects to normal tissues. Given their lack of toxicity compounds occurring naturally in the diet make ideal potential radiosensitizing agents. Capsaicin, a compound found in the Capsicum sp. of plants, is a widely consumed food additive in areas with low PCa incidence. Traditionally capsaicin is used to treat chronic pain syndromes; however, recently evidence using in vitro PCa models describes its anti-carcinogenic potential. The transient receptor potential vanilloid-receptor (TRPV)-1 and TRPV6 cation selective channels are thought to be partly responsible for mediating these effects. TRPV-1 and TRPV-6 expression is up-regulated in PCa tissue correlating directly with increasing tumor grade. This suggests TRPV1 and/or TRPV6 may be potential therapeutic targets for capsaicin mediated interventions in PCa patients. As IR and capsaicin both promote apoptosis and inhibit cell cycle progression in vitro we hypothesize an at least additive effect of combining these two therapies. Using clonogenic assays we assessed the effect of ionizing radiation (1-8 Gy) and/or capsaicin (1-10μM) on colony formation rates in 4 human PCa cell lines (LNCaP, PC3, PC3AR2, DU145). Proliferative, apoptotic, TRPV-6 protein markers were assessed using Western blot analyses. Exposure of cells to capsaicin (1-10μM) or IR (1-8Gy) caused significant dose-dependent inhibition of colony formation (p<0.001). Combining capsaicin with IR resulted in further significant inhibition of colony formation rates (P<0.001). Western blot analyses showed LNCaP cells treated with capsaicin and/or IR to have increased expression of pro-apoptotic proteins BAX and Bad, tumor-suppressor proteins p21 and p27 and reduced androgen-receptor. Additionally, capsaicin monotherapy caused a dramatic alteration in TRPV1 and TRPV6 expression. These studies confirm the radiosensitizing capacity of capsaicin in PCa cells in vitro. Ongoing studies using are further delineating the mechanism of interaction of these treatment modalities. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2493. doi:10.1158/1538-7445.AM2011-2493

Abstract 5724: Capsaicin and lycopene in combination reduce proliferation and induce apoptosis in prostate cancer cells via TRPV6 mediated phenomenon

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Introduction and Hypothesis: Prostate cancer (PCa) is the most common internal malignancy and the second most frequent cause of cancer death in Canadian men. Capsaicin recently investigated for its anti-cancer properties, is the active compound found in chilli peppers. Well-established as a pain reliever, capsaicin acts mainly on the transient receptor potential vanilloid (TRPV)-1 and TRPV6 receptor. The TRPV1 receptor is a non-selective cation channel that induces an inflow of cations Ca2+ and Na+ when activated. Similarly, activation of the TRPV6 receptor facilitates Ca2+ entry across the plasma membrane. Both TRPV1 and TRPV6 receptors are expressed in PCa tissue. Our present study aims to investigate the chemopreventive effect of capsaicin in combination with lycopene, an antioxidant found in tomatoes. We have found that PCa cells treated with capsaicin and lycopene alone and combined, cause a significant reduction in proliferation and an induction of apoptosis. Mechanistic studies examining this relationship have not been well defined. We hypothesize that capsaicin and lycopene in combination reduce proliferation and induce apoptosis via the TRPV6 and TRPV1 receptor in PCa cells in vitro. Materials and Methods: Two human PCa cell lines (LNCaP (AR+) and PC3 (AR-)) were analyzed. Cells were treated with capsaicin alone, or in combination with lycopene. Cells were incubated for up to 24 hours and proliferation assessed using MTS assay. Alterations in TRPV6, TRPV1, PSA, cell-regulatory molecules, and apoptotic markers were assessed by Western blot analysis. Results: There was a significant (P< 0.05) decrease in the proliferation of LNCaP and PC3 cells treated with capsaicin alone and in combination with lycopene (p< 0.001). Western blot analysis revealed a reduction (2-fold change) in PSA expression in LNCaP cells when treated with capsaicin alone. Interestingly this treatment resulted in the up-regulation in cell cycle marker p27 as well as cleaved PARP, in a time-dependent manner, demonstrating that the cells are undergoing cell cycle arrest and apoptosis. Further, we established that there is an up-regulation (3-fold change) of TRPV6 expression and an increase in TRPV1 expression with the treatment of capsaicin and lycopene alone and in combination. A plausible mechanism of action for this combination of capsaicin and lycopene is currently being investigated. Conclusions: We have shown for the first time that the TRPV6 receptor may play an important role in capsaicin and lycopene mediated cell-cycle arrest and apoptosis in human PCa cells. These studies may eventually help identify patients likely to benefit from the use of capsaicin in combination with lycopene. Ultimately these strategies may have a more meaningful impact on PCa morbidity and mortality than other therapeutic strategies currently in use. Funding: CIHR grant to VV. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5724.