Renal cell carcinoma (RCC), the predominant form of kidney cancer, is characterized by high resistance to radiation and chemotherapy. This study shows that expression of protein cross-linking enzyme transglutaminase 2 (TGase 2) is markedly increased in 7 renal cell carcinoma (RCC) cell lines in comparison to HEK293 and other cancer cell lines, such as NCI 60. However, the key role of TGase 2 in RCC was not clear. The down-regulation of TGase 2 was found to stabilize p53 expression, thereby inducing a 3- to 10-fold increase in apoptosis for 786-O, A498, CAKI-1, and ACHN cell lines by DAPI staining. MEF cells from TGase 2(-/-) mice showed stabilized p53 under apoptotic stress to compare to MEFs from wild-type mice. TGase 2 directly cross links the DNA binding domain of p53, leading to p53 depletion via autophagy in RCC. TGase 2 and p53 expression showed an inverse relationship in RCC cells. This finding implies that induced expression of TGase 2 promotes tumor cell survival through p53 depletion in RCC.
Keywords: autophagy; kidney cancer; protein cross-linking.