SLC38A1 promotes proliferation and migration of human colorectal cancer cells

Current studies have demonstrated that SLC38A1 proteins play a causal role in neoplastic cell transformation. The twofold aim of this study was to provide insight into whether a variance in the expression of SLC38A1 exists between human colorectal cancer and healthy human tissues and to determine how silencing or overexpressing the SLC38A1 gene could affect the proliferation, viability and migration of colorectal cancer cells. Immunohistochemical staining was used to analyze the expression of SLC38A1 in colorectal cancer tissues and adjacent normal mucosa in 77 patients who underwent surgical resection. The expression of SLC38A1 in colorectal cancer tissues and cell lines was detected using RT-PCR and Western blotting. Two colorectal cancer cell lines SW480 and HCT116 were used to examine whether silencing SLC38A1 with siRNA and overexpressing SLC38A1 with shRNA could affect cell viability and migration. As a result, the SLC38A1 protein was very low or undetectable in the normal colon mucosa. In contrast, strong staining of SLC38A1 protein was found in the cytoplasm in 79.2% colorectal cancer samples. More pronounced SLC38A1 expression in colorectal cancer tissues was significantly associated with tumor node metastasis (TNM) stage. Inhibition of SLC38A1 reduced tumour growth and suppressed proliferation and migration of SW480 cells. In contrast, overexpression of SLC38A1 had the opposite effects on HCT116 cells. SLC38A1 is overexpressed in colorectal cancer, which suggests that it is associated with tumour progression. These results encourage the exploration of SLC38A1 as a target for intervention in colorectal cancer.