Upregulation of the Kank1 gene-induced brain glioma apoptosis and blockade of the cell cycle in G0/G1 phase.

The Kank1 gene is one of the important members of the Kank gene family. As an important adaptor protein, Kank1 plays a significant role in the genesis and development of many malignant tumors. It was recently discovered that the Kank1 gene is a new cancer suppressor, and its expression is significantly downregulated or it is not expressed in kidney cancer, bladder cancer, prostate cancer, lung cancer and breast cancer. However, no report on the role of Kank1 in the genesis of brain glioma is available to date. In this study, we found significantly lower expression of the Kank1 gene in human brain glioma cells compared to the other cells evaluated. We used RNA interference techniques to silence Kank1 gene expression and found acceleration of tumor cell proliferation. However, when the Kank1 gene was upregulated, cell apoptosis occurred and the cell cycle was blocked in the G0/G1 phase. Also, we found that upregulating the Kank1 gene may result in the change of mitochondrial membrane potential, and the regulation of Bax and Bcl-2 may promote the mitochondria to release cytochrome C so as to activate Caspase-9 and -3. Thus, the human brain glioma apoptosis induced by upregulation of the Kank1 gene is closely relevant to the mitochondrial pathway.