Abstract:

Objective To investigate the effect of tetraspanin 1（Tspan1）overexpression on oxaliplatin （OXA）⁃induced apoptosis in human colorectal cancer cell line HCT116 and to analyze its possible mechanism of action. Methods HCT116 cells were transfected with Tspan1 overexpression plasmid and its negative control vec⁃ tor plasmid. The expression levels of Tspan1 mRNA and protein were detected by qRT⁃PCR and Western blot. The transfected HCT116 cells were treated with 14.15 μg/mL OXA or combined with 5 mmol/L autophagy inhibitor 3⁃ MA. MTT assay was used to detect cell proliferation. Flow cytometry was used to detect cell apoptosis. The expres⁃ sion of LC⁃3B protein was detected by immunofluorescence. The expression levels of autophagy⁃related proteins LC⁃ 3，Beclin1 and P62 were detected by Western blot. Results Overexpression of Tspan1 significantly up⁃regulated Tspan1 mRNA and protein expression levels in HCT116 cells，reduced the sensitivity of HCT116 cells to OXA，in⁃ hibited OXA⁃induced apoptosis of HCT116 cells，and enhanced the fluorescence intensity of LC3B protein，up⁃reg⁃ ulated the protein expression level of Beclin1 and the ratio of LC⁃3II/LC⁃3I，down⁃regulated the protein expression level of p62，and antagonized the induction of apoptosis by OXA. However，combined treatment with 3⁃MA re⁃ versed the inhibitory effect of Tspan1 overexpression on OXA ⁃induced apoptosis of HCT116 cells，and increased the sensitivity of cells to OXA. Conclusion Overexpression of Tspan1 antagonizes OXA ⁃ induced apoptosis in HCT116 cells by a mechanism that may be mediated through the induction of cellular autophagy.

Key words:

colorectal cancer, tetraspanin 1, oxaliplatin, autophagy, apoptosis