Novel quinuclidinone derivative 8a induced apoptosis in human MCF-7 breast cancer cell lines
Ahmed Malki1, Stephen C Bergmeier
1Biochemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt. amalky@yahoo.com
Abstract:
Novel quinuclidinone derivatives that cause cytotoxicity in human non-small lung carcinoma epithelial cells null for p53 (H1299) have been previously reported. The current study investigates the effect of these derivatives on cytotoxicity of human MCF-7 cells and normal breast epithelial cells (MCF-12a). This study shows that quinuclidinone derivatives 8a and 8b induce growth inhibition mainly through apoptosis of breast cancer cells (MCF-7) with less cytotoxic effect in normal breast epithelial cells (MCF-12a) for derivative 8a while 8b induced similar cytotoxicity for both breast cancer cells and normal breast epithelial cells. Derivative 8a was chosen for further investigation. 8a induced G(1) phase arrest, presumably sensitizing the breast cancer cells to apoptosis by increasing expression level of p21 and cyclin E. Moreover, 8a increased expression level of ERK1, p53 and BAX, and it reduced expression level of AKT and BCL-2. By investigating the sphingomyelinase apoptosis pathway, it was observed that 8a significantly increased sphingomyelinase activity and increased formation of ceramide as well as increased expression levels of JNK phoshorylation, caspase-8 and caspase-9. Based on previous results it is proposed that quinuclidinone derivative 8a provokes apoptosis in human breast cancer cells (MCF-7) via the sphingomyelinase pathway.
Insights
Novel quinuclidinone derivatives show promise in targeting breast cancer cells. Derivative 8a selectively induces apoptosis in MCF-7 cancer cells, offering a potential new therapeutic strategy with minimal impact on normal cells.
Area of Science:
- Pharmacology
- Cell Biology
- Oncology
Background:
- Previously identified quinuclidinone derivatives exhibited cytotoxicity against lung cancer cells.
- The current study explores the effects of these derivatives on breast cancer models.
Purpose of the Study:
- To evaluate the cytotoxicity of quinuclidinone derivatives 8a and 8b on human breast cancer cells (MCF-7) and normal breast epithelial cells (MCF-12a).
- To investigate the mechanism of action of the most promising derivative, 8a, in inducing apoptosis in breast cancer cells.
Main Methods:
- Cytotoxicity assays were performed on MCF-7 and MCF-12a cell lines.
- Cell cycle analysis and Western blotting were used to assess molecular changes induced by derivative 8a.
- Sphingomyelinase activity, ceramide formation, and apoptosis-related protein expressions were analyzed.
Main Results:
- Derivatives 8a and 8b inhibited MCF-7 cell growth via apoptosis.
- Derivative 8a demonstrated selective cytotoxicity towards MCF-7 cells compared to MCF-12a cells.
- Derivative 8a induced G(1) phase arrest, increased p21 and cyclin E expression, and modulated key apoptotic pathway proteins (ERK1, p53, BAX, AKT, BCL-2).
- Derivative 8a significantly activated the sphingomyelinase pathway, increasing sphingomyelinase activity, ceramide formation, JNK phosphorylation, caspase-8, and caspase-9 expression.
Conclusions:
- Quinuclidinone derivative 8a selectively induces apoptosis in human breast cancer cells (MCF-7).
- The mechanism involves G(1) cell cycle arrest and activation of the sphingomyelinase apoptosis pathway.
- Derivative 8a represents a potential therapeutic agent for breast cancer treatment.
