Abstract: Background and purpose: Solute carrier family 6 member 3 (SLC6A3) is highly expressed in patients with renal clear cell carcinoma. However, the effect of SLC6A3 on the metastasis of renal clear cell carcinoma and its molecular mechanism are still unclear. This study aimed to investigate the effect of SLC6A3 on proliferation and migration of renal clear cell carcinoma cells and its potential molecular mechanism. Methods: The expression of SLC6A3 in renal clear cell carcinoma and adjacent tissues collected in Shaanxi Cancer Hospital from January 2017 to January 2018 was detected by immunohistochemistry. The expression of SLC6A3 in renal clear cell carcinoma cell line SNU-349 was detected by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) and Western blot. ShNC and shSLC6A3 plasmids were constructed and transfected into SNU-349 cells. Changes in cell proliferation, apoptosis and invasion ability of SLC6A3 downregulated cells were detected by cell counting kit-8 (CCK-8) assay, flow cytometry and transwell assay. The effects of SLC6A3 downregulation on phosphoinositide 3-kinase (PI3K)/ protein kinase B (Akt) signaling pathway were analyzed by Western blot. Results: SLC6A3 was highly expressed in renal clear cell carcinoma tissues and cells (P<0.05). After SLC6A3 was downregulated, cell proliferation and invasion ability were significantly decreased (P<0.05), apoptotic rate was significantly increased (P<0.05), and cell cycle S-phase arrest was observed (P<0.05). The expression levels of PI3K and phosphorylation levels of Akt in cells were significantly reduced after SLC6A3 was downregulated (P<0.05). Conclusion: SLC6A3 is highly expressed in renal clear cell carcinoma tissues. Downregulation of SLC6A3 inhibits cell proliferation and invasion, and promotes cell apoptosis. SLC6A3 may affect the growth of SNU-349 cells by regulating the PI3K/Akt signaling pathway.

Key words: Renal clear cell carcinoma, Solute carrier family 6 member 3, Proliferation, Migration