[Inhibition of G9a attenuates cell proliferation via the mitochondrial apoptosis pathway in lung adenocarcinoma]
1Department of Thoracic Surgery, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, China.
Abstract:
Objective: The aim of this study is to investigate the effect of G9a inhibitor BIX-01294 on attenuating cell proliferation in human lung adenocarcinoma A549 cell line and the underlying molecular mechanism. Methods: Treated with BIX-01294, the growth and proliferation of A549 cells were detected by MTT assay and colony formation assay, and its impact on cell apoptosis was analyzed using flow cytometry. By Western blot, we explored the alterations in the expression of apoptosis-related proteins and the G9a catalysate, H3K9me and H3K9me2. In addition, in the pretreatment with caspase inhibitor Z-VAD-FMK, we detected the apoptotic dependence of BIX-01294 attenuating impact on A549 cell proliferation. Results: Compared with the control group, the histone methyltransferase G9a inhibitor BIX-01294 attenuated cell proliferation in A549 cells in a dose- and time-dependent manner. There were 42.5±8.7 colonies after BIX-01294 (10 μmol/L) treatment for 7 days, while 172.7±23.0 colonies in the control group, with a statistical significance (P<0.05). After treatment with BIX-01294 (10 μmol/L) for 24 hours, the cell apoptotic rate was(47.6±8.4)%, with a significant difference in comparison with the control group [(7.2±3.6)%, P<0.05]. The expression of G9a catalysate, H3K9me and H3K9me2 was downregulated, the same with anti-apoptotic protein Bcl-2, while the proteins in mitochondrial apoptosis pathway, Bax, Bak and cleaved caspase-9, were upregulated, so was the expression of cleaved caspase-3 and cleaved PARP, and there was no alteration in the expression of cleaved caspase-8, which is a protein related with death receptor apoptosis pathway. Furthermore, after Z-VAD-FMK pretreatment, the cell apoptotic rate was decreased significantly, and the expression of apoptosis-related proteins were downregulated. Conclusions: Our results indicate that BIX-01294 can attenuate cell proliferation in lung adenocarcinoma, and it can be considered as one of the underlying mechanisms, the apoptosis may be induced by activating mitochondrial pathway.
Insights
The G9a inhibitor BIX-01294 effectively reduces lung adenocarcinoma cell proliferation by inducing apoptosis. This mechanism involves the mitochondrial pathway and affects key apoptosis-related proteins.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Lung adenocarcinoma is a major cause of cancer-related deaths worldwide.
- Histone methyltransferase G9a plays a role in cell proliferation and cancer progression.
- Targeting G9a offers a potential therapeutic strategy for lung adenocarcinoma.
Purpose of the Study:
- To investigate the effect of G9a inhibitor BIX-01294 on human lung adenocarcinoma A549 cell proliferation.
- To elucidate the underlying molecular mechanisms, including apoptosis induction.
- To assess the role of the mitochondrial apoptosis pathway.
Main Methods:
- A549 cells were treated with BIX-01294.
- Cell proliferation was assessed using MTT and colony formation assays.
- Apoptosis was analyzed by flow cytometry and Western blotting for apoptosis-related proteins.
- The role of caspase activation was investigated using Z-VAD-FMK pretreatment.
Main Results:
- BIX-01294 significantly attenuated A549 cell proliferation in a dose- and time-dependent manner.
- BIX-01294 treatment led to a significant increase in apoptosis rate.
- Downregulation of H3K9me, H3K9me2, and Bcl-2, with upregulation of Bax, Bak, cleaved caspase-9, cleaved caspase-3, and cleaved PARP was observed.
- Apoptosis induction was dependent on the mitochondrial pathway, not the death receptor pathway.
Conclusions:
- BIX-01294 demonstrates potent anti-proliferative effects on lung adenocarcinoma cells.
- Apoptosis induction via the mitochondrial pathway is a key mechanism of BIX-01294's action.
- BIX-01294 represents a promising therapeutic agent for lung adenocarcinoma.
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