Study on Cellular Localization of Bin Toxin and its Apoptosis-inducing Effect on Human Nasopharyngeal Carcinoma Cells
Simab Kanwal1, Panadda Boonserm1
1Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom, 73170, Thailand.
Background:
Bacterial pore-forming toxins, BinA and BinB together known as the binary toxin are potent insecticidal proteins, that share structural homology with antitumor bacterial parasporin-2 protein. The underlying molecular mechanism of Bin toxin-induced cancer cell cytotoxicity requires more knowledge to understand whether the toxin induced human cytotoxic effects occur in the same way as that of parasporin-2 or not.
Methods:
In this study, anticancer properties of Lysinibacillus sphaericus derived Bin toxin on HK1 were evaluated through MTT assay, morphological analysis and lactate dehydrogenase efflux assay. Induction of apoptosis was determined from RT-qPCR, caspase activity and cytochrome c release assay. Internalization pattern of Bin toxin in HK1 cells was studied by confocal laser-scanning microscopic analysis.
Results:
Activated Bin toxin had strong cytocidal activity to HK1 cancer cell line at 24 h postinoculation. Both BinA and BinB treated HK1 cells showed significant inhibition of cell viability at 12 μM. Induction of apoptotic mediators from RT-qPCR and caspase activity analyses indicated the activation of programmed cell death in HK1 cells in response to Bin toxin treatment. Internalization pattern of Bin toxin studied by using confocal microscopy indicated the localization of BinA on cell surface and internalization of BinB in the cytoplasm of cancer cells as well as colocalization of BinA with BinB. Evaluation of cytochrome c release also showed the association of BinB and BinA+BinB with mitochondria.
Conclusion:
Bin toxin is a cytotoxic protein that induces cytotoxic and apoptotic events in HK1 cells, and may have high therapeutic potential as an anti-cancer agent.
Insights
Lysinibacillus sphaericus binary toxin (Bin toxin) effectively kills HK1 cancer cells by inducing apoptosis. This cytotoxic protein shows potential as an anticancer therapeutic agent.
Area of Science:
- Microbiology
- Molecular Biology
- Cancer Research
Background:
- Binary toxins (BinA and BinB) from Lysinibacillus sphaericus are insecticidal proteins with structural similarities to parasporin-2.
- The precise mechanism of Bin toxin's cytotoxicity in human cancer cells remains unclear.
- Investigating Bin toxin's action is crucial to understand its potential therapeutic applications.
Purpose of the Study:
- To evaluate the anticancer properties of Lysinibacillus sphaericus derived Bin toxin on the HK1 cancer cell line.
- To elucidate the molecular mechanisms underlying Bin toxin-induced cancer cell death, including apoptosis induction and cellular uptake.
Main Methods:
- MTT assay, morphological analysis, and lactate dehydrogenase efflux assay were used to assess cytotoxicity.
- Apoptosis induction was determined via RT-qPCR, caspase activity assays, and cytochrome c release.
- Confocal laser-scanning microscopy was employed to study Bin toxin internalization patterns in HK1 cells.
Main Results:
- Bin toxin demonstrated significant cytocidal activity against HK1 cells at 12 μM, inhibiting cell viability.
- Apoptotic mediators were induced, indicating programmed cell death activation.
- BinA localized on the cell surface, BinB internalized into the cytoplasm, and both colocalized, with BinB associating with mitochondria.
Conclusions:
- Bin toxin induces cytotoxic and apoptotic events in HK1 cancer cells.
- The study suggests Bin toxin possesses high therapeutic potential as an anticancer agent.
- Further research into Bin toxin's mechanism could lead to novel cancer therapies.
