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Alteration of caspase-3 (CPP32/Yama/apopain) in wild-type MCF-7, breast cancer cells
H Kurokawa1, K Nishio, H Fukumoto
1Pharmacology Division, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045, Japan.
Abstract:
Caspase-3 (CPP32/Yama/apopain), one of the interleukin 1 -converting enzyme (ICE)-like proteases (caspases), is anticipated to mediate apoptotic cell death. We observed the expression of caspase-3 in various cancer cell lines and lack of normal expression of mRNA and protein in MCF-7, human breast carcinoma cell line. Sequence analysis of cDNA showed 125 nucleotides deletion in spite of no gross gene alteration of caspase-3 in MCF-7. The possible cause is altered splicing of the fragment followed by frame shift at translation level. MCF-7 cells are widely used in the research of apoptosis because of the high sensitivity to tumor necrosis factor induced cell death. However, our results suggest the existence of other apoptotic pathways independent on caspase-3 at least in MCF-7 cells.
Insights
This study found that caspase-3, a key protein in apoptosis, is not expressed in MCF-7 breast cancer cells due to a genetic alteration. This suggests alternative cell death pathways exist in these cancer cells.
Area of Science:
- Molecular Biology
- Cell Biology
- Cancer Research
Background:
- Caspase-3 (CPP32/Yama/apopain) is a critical protease involved in programmed cell death (apoptosis).
- MCF-7 cells, a human breast carcinoma line, are frequently used to study apoptosis due to their sensitivity to TNF-induced cell death.
Purpose of the Study:
- To investigate the expression and potential role of caspase-3 in the MCF-7 human breast carcinoma cell line.
- To identify the molecular basis for any observed alterations in caspase-3 expression in MCF-7 cells.
Main Methods:
- Analysis of caspase-3 mRNA and protein expression in various cancer cell lines, including MCF-7.
- Sequencing of caspase-3 cDNA from MCF-7 cells to detect genetic alterations.
- Evaluation of apoptotic pathways in MCF-7 cells.
Main Results:
- Normal expression of caspase-3 mRNA and protein was absent in the MCF-7 cell line.
- Sequence analysis revealed a 125-nucleotide deletion in the caspase-3 cDNA of MCF-7 cells.
- This deletion likely results from altered splicing, leading to a frame shift during translation.
- MCF-7 cells exhibit sensitivity to tumor necrosis factor-induced cell death, independent of caspase-3.
Conclusions:
- The absence of functional caspase-3 in MCF-7 cells is attributed to a specific cDNA deletion caused by aberrant splicing.
- These findings indicate that apoptosis can occur through caspase-3-independent pathways in human breast carcinoma cells.
- The study highlights the complexity of apoptotic mechanisms and suggests alternative routes for cell death in cancer research.