Monobenzyltin Complex C1 Induces Apoptosis in MCF-7 Breast Cancer Cells through the Intrinsic Signaling Pathway and through the Targeting of MCF-7-Derived Breast Cancer Stem Cells via the Wnt/β-Catenin Signaling Pathway.

Somayeh Fani,Najihah Mohd Hashim,Hapipah Mohd Ali,Behnam Kamalidehghan,Yeap Swee Keong,Hamed Karimian,Kit May Chow,Firouzeh Dehghan,Siyamak Ebrahimi Nigjeh,Kong Mun Lo,Rahman Soori,Surinder K Batra

doi:10.1371/journal.pone.0160836

Somayeh Fani, Najihah Mohd Hashim + Show 10 more

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https://doi.org/10.1371/journal.pone.0160836

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Abstract

Monobenzyltin Schiff base complex, [N-(3,5-dichloro-2-oxidobenzylidene)-4-chlorobenzyhydrazidato](o-methylbenzyl)aquatin(IV) chloride, C1, is an organotin non-platinum metal-based agent. The present study was conducted to investigate its effects on MCF-7 cells with respect to the induction of apoptosis and its inhibitory effect against MCF-7 breast cancer stem cells. As determined in a previous study, compound C1 revealed strong antiproliferative activity on MCF-7 cells with an IC50 value of 2.5 μg/mL. Annexin V/propidium iodide staining coupled with flow cytometry indicated the induction of apoptosis in treated cells. Compound C1 induced apoptosis in MCF-7 cells and was mediated through the intrinsic pathway with a reduction in mitochondrial membrane potential and mitochondrial cytochrome c release to cytosol. Complex C1 activated caspase 9 as a result of cytochrome c release. Subsequently, western blot and real time PCR revealed a significant increase in Bax and Bad expression and a significant decrease in the expression levels of Bcl2 and HSP70. Furthermore, a flow cytometric analysis showed that treatment with compound C1 caused a significant arrest of MCF-7 cells in G0/G1 phase. The inhibitory analysis of compound C1 against derived MCF-7 stem cells showed a significant reduction in the aldehyde dehydrogenase-positive cell population and a significant reduction in the population of MCF-7 cancer stem cells in primary, secondary, and tertiary mammospheres. Moreover, treatment with C1 down-regulated the Wnt/β-catenin self-renewal pathway. These findings indicate that complex C1 is a suppressive agent of MCF-7 cells that functions through the induction of apoptosis, cell cycle arrest, and the targeting of MCF-7-derived cancer stem cells. This work may lead to a better treatment strategy for the reduction of breast cancer recurrence.

Highlights

Breast cancer is the second most common cancer type that affects women
We present the apoptotic response of our novel drug, organotin complex [N-(3,5-dichloro-2-oxidobenzylidene)-4-chlorobenzyhydrazidato](o-methylbenzyl) aquatin(IV) chloride, C1, in cells subjected to complex C1 through an evaluation of the following: caspase 3/7, 8, 9 activities, changes in Bcl2, Bax, and Bad expression, cell cycle arrest, cytochrome c release, changes in Mitochondrial Membrane Potential, membrane potential (MMP), nuclear morphology, and phosphatidyl serine (PS) exposure on the cell surface
Compound C1 selectively promotes the death of tumor cells through apoptosis and cell cycle arrest

Summary

Introduction

Breast cancer is the second most common cancer type that affects women. Chemotherapy, along with a panel of breast cancer drugs, is the most common treatment for this disease. These drugs are categorized as alkylating agents, cytotoxic antibiotics, mitotic and topoisomerase inhibitors, anti-tumor agents and anti-metabolites [2]. Due to the side effects and the development of resistance to chemotropic drugs, the investigation of new anti-cancer agents from various resources must continue. Based on these consequences of cancer treatment, the inclination towards synthetic compounds has been markedly increased [2]

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