Abstract 3487: A novel role of transient receptor potential vanilloid type 2 (TRPV2) for augmentation of chemotherapeutic drug efficacy in triple-negative breast cancer

Abstract

Abstract Transient receptor potential vanilloid type 2 (TRPV2) is a non-selective cation channel that is triggered by agonists like cannabidiol (CBD). Chemotherapeutic drugs such as doxorubicin (DOX) and paclitaxel (PAC) are routinely used for treatment of Triple negative breast cancer (TNBC) patients however, these drugs are usually resisted and show limited efficacy and more side effects at higher doses. In the present study, we analyzed the ability of TRPV2 activation in enhancing the chemotherapeutic efficacy in TNBC cells. Interestingly, we found that TRPV2 is significantly up regulated in primary and metastatic breast tumor tissues compared to normal breast tissues using tissue microarray analysis. In addition, using publically available Kaplan Miere Plotter datasets, we found that estrogen receptor (ER) negative patients with higher TRPV2 expression levels and committed to anti-tumor chemotherapy have significantly higher survival than patients committed to anti-tumor chemotherapy but have lower TRPV2 expression levels. Our in vitro studies showed that TNBC cells subjected to combination treatment of CBD and DOX show enhanced proliferation inhibition compared to cells treated with DOX only . Analysis of molecular mechanisms showed higher levels of cleaved PARP and cleaved Caspase-3 in combination treatment compared to Dox alone. Further studies revealed that CBD activates more uptake of DOX into TNBC cells. This increased uptake was abrogated upon treatment with specific TRPV2 blocker. Furthermore, TRPV2 blocker inhibited the increased levels of cleaved PARP and cleaved caspase-3 in the combination treatment. By using two orthotopic mouse model, we showed that mice treated with CBD in combination with doxorubicin have significantly less tumor weight, fewer Ki67 and CD31 positive cells, and significantly higher level of cleaved caspase 3 and cleaved PARP compared to the mice treated with CBD or DOX alone. This study suggests the use of TRPV2 agonists as an adjuvant therapy to improve the anti-tumor chemotherapeutic efficacy especially in TNBC patients. Citation Format: Mohamad M. Elbaz, Mohd W. Nasser, Helong Zhao, Ramesh K. Ganju. A novel role of transient receptor potential vanilloid type 2 (TRPV2) for augmentation of chemotherapeutic drug efficacy in triple-negative breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3487. doi:10.1158/1538-7445.AM2015-3487