Targeted inhibition of ACK1 can inhibit the proliferation of hepatocellular carcinoma cells through the PTEN/AKT/mTOR pathway

Activated Cdc42-associated kinase 1 (Ack1) expression is upregulated in hepatocellular carcinoma (HCC) tissues and other tumour tissues. However, the function and regulatory mechanism of Ack1 in HCC remains unclear. In this study, the expression of pTyr284-ACK1, pSer473-AKT and PTEN in HCC was detected by immunohistochemistry, and its clinicopathological significance was analysed. Then, ACK1-targeted small molecule inhibitors AIM-100 and Dasatinib were used to treat cells SK-Hep-1 and HepG2, and changes in activity and biological behaviours of PTEN/Akt/mTOR signalling pathway were observed. The results showed that pTyr284-ACK1 protein was highly expressed in HCC tissues and was related to the poor prognosis of patients; the expression of pTyr284-ACK1 protein was positively correlated with pSer473-AKT and negatively correlated with PTEN. In addition, after treatment either with AIM-100 or Dasatinib, both proliferation of two cells and migration, invasion of SK-Hep-1 cells were all significantly inhibited. Meanwhile, Ack1, pTyr284-ACK1, pSer473-AKT, mTOR and EGFR were down-regulated; PTEN was up-regulated when analysed by western-blot in SK-Hep-1 cells. These results demonstrated that Ack1 may promote HCC development via PTEN/Akt/mTOR pathway. Targeted inhibition of Ack1 may be a novel therapeutic strategy for HCC. SIGNIFICANCE OF THE STUDY: Hepatocellular carcinoma (HCC) is a common malignant tumour with high mortality. Our study showed that Ack1 and pTyr284-ACK1 are highly expressed in HCC and may promote HCC development through the PTEN/Akt/mTOR signalling pathway. Targeted inhibition of Ack1 expression with small inhibitors AIM-100 and Dasatinib may weaken tumour cells ability of proliferation, migration and invasion. Our results suggested that downregulation of Ack1 may be a potential therapeutic strategy for HCC.