Prohibitin Links Cell Cycle, Motility and Invasion in Prostate Cancer Cells.

Prohibitin () is a tumour suppressor gene with several different molecular activities. PHB overexpression leads to G1/S-phase cell cycle arrest, and PHB represses the androgen receptor (AR) in prostate cancer cells. PHB interacts with and represses members of the E2F family in a manner that may also be AR-linked, therefore making the AR:PHB:E2F interaction axis highly complex. siRNA increased the growth and metastatic potential of LNCaP mouse xenografts in vivo. Conversely, ectopic cDNA overexpression affected several hundred genes in LNCaP cells. Furthermore, gene ontology analysis showed that in addition to cell cycle regulation, several members of the family were significantly downregulated (, and ), as well as pathways for cell adhesion. Online GEO data studies showed expression to be decreased in clinical cases of metastatic prostate cancer, and to be correlated with higher WNT expression in metastasis. overexpression reduced prostate cancer cell migration and motility in wound-healing assays, reduced cell invasion through a Matrigel layer and reduced cellular attachment. In LNCaP cells, , and expression were also upregulated by androgen treatment and downregulated by androgen antagonism, indicating a role for AR in the control of these genes. However, these were strongly cell cycle regulated. cDNA ectopic expression and siRNA (both cell cycle promoting effects) increased , and expression, and these genes were also upregulated as cells were released from G1 to S phase synchronisation, indicating further cell cycle regulation. Therefore, the repressive effects of PHB may inhibit , and expression and its loss may increase metastatic potential in human prostate cancer.