[Effect of SLC7A5 on the proliferation of tumor cells and its relationship with transforming growth factor-β1 signal pathway]

To explore the biological effects of amino acid transporter gene SLC7A5 (solute carrier family 7, member 5) on tumor cells and the regulatory mechanism at transcriptional level. Methods: The expression of SLC7A5 was examined in human normal tissues and corresponding tumor tissues by Gene Expression Omnibus (GEO) database. The recombinant plasmid of SLC7A5 gene was constructed, and the effect of the SLC7A5 gene on tumor cell proliferation was investigated by methylthiazolyldiphenyl-tetrazolium bromide (MTT) and flow cytometry. SLC7A5 gene promoter and transcription factor binding sites were predicted through bioinformatics analysis, and the gene promoter recombinant plasmid was constructed. Then the dual luciferase reporter gene assay and reverse transcription polymerase chain reaction (RT-PCR) were used to explore the regulation of transforming growth factor-β1 (TGF-β1) signal on SLC7A5 gene expression. Results: The GEO database analysis showed that the distribution of SLC7A5 was tissue specific, and its expression level was significantly higher in the tumor tissues than that in the corresponding normal tissues. The results of MTT and flow cytometry showed that SLC7A5 could promote cell proliferation. Results from the promoter analysis, reporter gene assay and RT-PCR confirmed that TGF-β1 could up-regulate the activity of SLC7A5 promoter and promote the expression of the SLC7A5 gene. Conclusion: SLC7A5 gene plays a role in promoting tumor development, which is regulated by the TGF-β1 signaling pathway.