Executive Summary : | Treatment of Triple Negative Breast Cancer (TNBC) is a challenge due to its aggressive behaviour; poor clinical outcome and likely to relapse. The heterogeneity and lack of actionable targets has been a major challenge in developing better therapies for TNBC. Though chemotherapy with taxanes remains standard-of-care treatment option for advance-stage TNBC patients, however, the response is often short and associated with chemo-resistance and poor prognosis with median overall survival of 9-12 months. Therefore, new target-based approach is urgently needed for the effective management of this aggressive form of disease. Using combination of simvastatin (SIM) and enzalutamide (ENZ) as safe, efficacious, and cost-effective agents to treat TNBC or its use as adjuvant in therapy, our proposal aims in the development of new combinatorial therapy for the treatment of TNBC. Cholesterol synthesis through 3-hydroxy-3-methylglutaryl-Coenzyme A reductase (HMG-CoAR) is critical in maintaining androgen receptor (AR) levels in TNBC. Besides increased HMG-CoAR level/activity in TNBC is involved in tumorigenesis, progression, proliferation, migration, and survival of TNBC tumor cells. The central hypothesis is that a combination of HMG-CoAR inhibition with statins and AR inhibition with enzalutamide is a new approach to treat AR-positive TNBC. This is the first study utilizing a combination of SIM and ENZ treatment to significantly reduce cell viability in the highly aggressive AR-positive TNBC and its subclone cells, and to potentially identify a synergistic mechanism-base relationship between SIM and ENZ in combination. The aim of the present study is to investigate the effect and mechanism of combination of SIM and ENZ on AR-positive highly aggressive subclones and metastatic TNBC cells and in in vivo studies. The anti-proliferative activity of SIM and ENZ and inhibition of AR and HMG-CoAR will be evaluated by MTT assay. Flow cytometry will be used to examine the effect of SIM and ENZ on cell cycle and apoptosis. The Cholesterol Quantitation Kit will be used to determine the concentration of free cholesterol or total cholesterol. Inhibition of HMG-CoAR with simvastatin and AR inhibition with enzalutamide and their combination, Ser-872 phosphorylation of HMG-CoAR on AR-positive highly aggressive subclones and metastatic TNBC will be analyzed by and Western blotting. |