stilbenes and salinomycin

Resveratrol is a dietary compound that has been widely reported for its anticancer activities. However, successful extrapolation of its effects to pre-clinical studies is met with limited success due to inadequate bioavailability. We investigated the potential of combination therapy to improve the efficacy of resveratrol in a more physiologically relevant dose range.. The effect of resveratrol on canonical Wnt signaling was evaluated by Western blotting. Wnt modulators HLY78 (activator) and salinomycin (inhibitor) were evaluated in combination with resveratrol for their effect on breast cancer cell viability (MTT assay), cell cycle progression and apoptosis (Western blotting). Bliss independency model was used to evaluate combinatorial effects of resveratrol-salinomycin combination.. Resveratrol downregulated canonical Wnt signaling proteins in treated breast cancer cells (MCF-7, MDA-MB-231 and MDA-MB-468) in the dose range of 50-200μM, which also affected cellular viability. However, at very low doses (0-50μM), resveratrol exhibited no cellular toxicity. Co-treatment with salinomycin significantly potentiated the anti-cancer effects of resveratrol, whereas HLY78 co-treatment had minimal effect. Bliss independency model revealed that Wnt inhibition synergistically potentiates the effects of resveratrol in MCF-7 and BT474 cells. Significantly downregulated canonical Wnt signaling proteins and marker of epithelial-mesenchymal transition (EMT), vimentin were observed in cells treated with resveratrol-salinomycin combination. Cell cycle arrest, caspase activation and apoptosis induction in cells treated with resveratrol-salinomycin combination further confirmed the efficacy of the combination.. We report a novel resveratrol-salinomycin combination for targeting ER-positive breast cancer cells and present evidence for successful pre-clinical implementation of resveratrol.

Topics: Anti-Bacterial Agents; Antineoplastic Agents, Phytogenic; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Drug Therapy, Combination; Female; Gene Expression Regulation, Neoplastic; Humans; Pyrans; Receptors, Estrogen; Resveratrol; Signal Transduction; Stilbenes; Wnt Proteins

Resveratrol (RES) is a natural polyphenol having anti-proliferative activity against breast cancer cells. RES in combination with other chemo modulatory agents, minimizes toxicity and increases efficacy of the treatment. Salinomycin (SAL), a monocarboxylic polyether ionophore is known for selectively targeting breast cancer stem cells. Purpose of the present study was to investigate whether RES in combination with SAL exerts synergistic anti-proliferative activity on breast cancer cells. We further evaluated the molecular mechanism behind SAL and RES mediated cell death. Cytotoxicity assay was performed to determine 50% inhibitory concentration (IC50) of SAL and RES in different human breast cancer cells (HBCCs). Drug synergism and combination index (CI) were calculated using CompuSyn software and effects of synergistic combinations (CI < 1) involving lower doses of SAL and RES were selected for further studies. This combination significantly induced apoptosis in HBCCs without affecting non tumorigenic human breast epithelial cells MCF-10A. Co-treatment enhanced apoptosis in MCF-7 cells via reactive oxygen species (ROS) mediated mitochondrial dysfunction. Oxidative stress disrupt redox homeostasis which altered antioxidant enzymes viz. CuZn Superoxide dismutase (SOD), MnSOD and catalase. Additionally, combination altered nuclear morphology, enhanced PARP cleavage and led to caspase activation. SAL and RES also synergistically modulated MAPK pathway. Study suggests that SAL and RES offer a novel combination approach for the treatment of breast cancer.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Female; Flow Cytometry; Humans; Inhibitory Concentration 50; MAP Kinase Signaling System; MCF-7 Cells; Pyrans; Reactive Oxygen Species; Resveratrol; Stilbenes; Tumor Stem Cell Assay

Resveratrol (RSVL) a dietary phytochemical showed to enhance the efficacy of chemotherapeutic drugs. Recently, Salinomycin (SAL) has gained importance as cancer therapeutic value for breast cancer (BC), however, its superfluxious toxicity delimits the utility. Taking the advantage of RSVL, the therapeutic efficacy of RSVL and SAL combination was studied in vitro and in vivo system. Firstly, the synergistic combination dose of RSVL and SAL was calculated and further, the efficacy was examined by wound healing, and Western blots analysis. Further, in vivo study was performed to confirm the effect of colony formation and apoptosis detection by flow cytometry based assays. Further, the molecular mode of action was determined at both transcript and translational level by quantitative Real Time PCR combination in Ehrlich ascitic carcinoma model.The combination of IC20 (R20) of RSVL and IC10 (S10) dose of SAL showed best synergism (CI<1) with ∼5 fold dose advantage of SAL. Gene expression results at mRNA and protein level revealed that the unique combination of RSVL and SAL significantly inhibited epithelial mesenchymal transition (Fibronectin, Vimentin, N-Cadherin, and Slug); chronic inflammation (Cox2, NF-kB, p53), autophagy (Beclin and LC3) and apoptotic (Bax, Bcl-2) markers. Further, i n vivo study showed that low dose of SAL in combination with RSVL increased life span of Ehrlich ascitic mice. Overall, our study revealed that RSVL synergistically potentiated the anticancer potential of SAL against triple negative BC.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Autophagy; Cadherins; Cell Line, Tumor; Cell Proliferation; Drug Synergism; Epithelial-Mesenchymal Transition; Female; Humans; Mice; NF-kappa B; Pyrans; Resveratrol; Stilbenes; Triple Negative Breast Neoplasms