TMEM106a is a Novel Tumor Suppressor in Human Renal Cancer

Background/Aims: In recent years the diagnosis and management of renal cancer has changed greatly, although the mechanism is still elusive. TMEM106a is a conserved type II transmembrane protein which is a key factor to regulate macrophage activation. Its inactivation in gastric cancer is frequently observed to be associated with poor prognosis. The role of TMEM106a in renal cancer remained unclear. Methods: TMEM106a expression profiling was performed in a panel of renal cancer cell lines and primary renal tissue cells. Then TMEM106a was overexpressed by a viral system in a renal cancer cell line with low level of TMEM106a. This stable cell line was assessed in multiple cell growth and migration assays. The results from TMEM106a overexpressing cell line were then confirmed with primary renal cells by siRNA knockdown of TMEM106a. Results: TMEM106a expression level was reduced in renal cancer cells compared to normal primary renal cells. Restoration of TMEM106a expression in TMEM106a-low renal cancer cells resulted in attenuated proliferation, reduced cell migration and enhanced caspase 3 dependent apoptosis compared to control cells. TMEM106a knockdown in primary renal cells led to increased colony formation compared to the control cells with scrambled siRNA transfection. Conclusion: TMEM106a is a novel tumor suppressor in renal cancer