Centchroman induces G0/G1 arrest and caspase-dependent apoptosis involving mitochondrial membrane depolarization in MCF-7 and MDA MB-231 human breast cancer cells.

Abstract

Studies with Centchroman (CC) as a candidate anti-breast cancer agent are into phase III multicentric clinical trial in stage III/IV breast cancer. We have previously demonstrated its anti-neoplastic activity in Estrogen Receptor positive (ER+ve) MCF-7 Human Breast Cancer Cells (HBCCs). We now present the basis for anti-neoplastic activity of CC, mediated through apoptosis in both ER+ve/-ve MCF-7 and MDA MB-231 HBCCs respectively, compared to Tamoxifen (TAM) as a positive control. All the experiments were performed with 48 h estrogen-deprived cells exposed to CC/TAM for the subsequent 48 h. Cytotoxic potential of CC was assessed through SRB assay. Cell-cycle analysis, Time-dependent cytotoxicity, Reactive Oxygen Species (ROS) and Mitochondrial Membrane Permeability were investigated by Flow Cytometry. Early-stage apoptosis was detected by Annexin-PI staining. Caspases were assayed colorimetrically whereas nuclear derangements were assessed morphologically through PI staining and finally by DNA fragmentation analysis. Cell viability studies confirmed the IC50 of CC in MCF-7 and MDA MB-231 cells to be 10 and 20 microM (P < 0.001) respectively, suggesting enhanced susceptibility of the former cell type to CC. FACS data reveals CC mediated G0/G1 arrest (P < 0.01) along with the presence of prominent sub-G0/G1 peak (P < 0.001) in both the cell types suggesting ongoing apoptosis. Phosphatidylserine externalization, mitochondrial events, caspase evaluation and nuclear morphology changes reveal initiation/progression of caspase-dependent apoptosis even at a dose of 1 microM which eventually leads to DNA fragmentation in both the cell types. Results demonstrate that CC induces caspase-dependent apoptosis in MCF-7 and MDA MB-231 cells irrespective of ER status similar to TAM in terms of anti-neoplastic activity.

• Authors: Manisha Nigam, Vishal Ranjan, Swasti Srivastava, Ramesh Sharma, Anil K Balapure
• Journal: Life sciences (Life Sci) Vol. 82 Issue 11-12 Pg. 577-90 (Mar 12 2008) ISSN: 0024-3205 [Print] Netherlands
• PMID: 18279897 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antineoplastic Agents
• Estrogen Antagonists
• Tamoxifen
• Centchroman
• Caspases

Topics

• Antineoplastic Agents (pharmacology)
• Apoptosis (drug effects, physiology)
• Breast Neoplasms
• Caspases (metabolism)
• Cell Line, Tumor
• Cell Nucleus (ultrastructure)
• Cell Shape
• Cell Survival (drug effects)
• Centchroman (pharmacology)
• Clinical Trials as Topic
• DNA Fragmentation
• Estrogen Antagonists (pharmacology)
• Female
• G1 Phase (drug effects)
• Humans
• Membrane Potentials (physiology)
• Mitochondria (drug effects, metabolism)
• Resting Phase, Cell Cycle (drug effects)
• Tamoxifen (pharmacology)