9891

NUAK1

NUAK family, SNF1-like kinase, 1;NUAK1;NUAK family, SNF1-like kinase, 1

AMP-activated protein kinase family member 5|AMPK-related protein kinase 5|NUAK family SNF1-like kinase 1|omphalocele kinase 1

12q23.3

protein-coding

PURPOSE: To investigate the effects of Akt/ARK5 pathways on the metastatic potential of human breast cancer cells. MATERIALS AND METHODS: The human ARK5 gene was transfected into MDA-MB-231 cells. Effects of ARK5 on MDA-MB-231 cells were investigated in vitro. The tumorigenicity and spontaneously metastatic capability regulated by ARK5 were determined using an orthotopic xenograft tumor model. RESULTS: ARK5 enhanced the invasive and metastatic potential of MDA-MB-231 cells under regulation by Akt. The enhancement was associated with increasing MMP-2, MMP-9, and MT1-MMP expression. The results were further demonstrated by RNA interference experiment. In an in vivo study, we also demonstrated that ARK5-transfected breast cancer cells grew faster and had more pulmonary metastases than its parental counterparts. CONCLUSION: ARK5 led to a more invasive phenotype and metastatic potential in human breast cancer dependent on Akt.

We recently identified a novel human AMPK family member, ARK5, and discovered that is a major factor in Akt-dependent cancer cell survival and migration activity through activation of MT1-MMPs in vitro. The mRNA expression of other AMPK family members and ARK5 was measured using RT-PCR in human colorectal carcinoma cell lines DLD-1, WiDr, HCT-15, SW620, LoVo, SW480, and mRNA expression of AMPK-alpha1, SNARK, MELK and ARK5, but not AMPK-alpha2, was detected in every line. Quantitative-PCR (Q-PCR) to estimate the amount of ARK5 mRNA expression in the cell lines showed that there is a variety of ARK5 expressions among the cell lines and high expression was observed in a cell line derived from the metastatic lesion, LoVo. To determine the effect of ARK5 overexpression on metastasis in vivo, we established human pancreas cancer cell line PANC-1 stably transfected with ARK5 full-length expression vector (P/ARK) and DLD-1 stably transfected with the same vector (D/ARK). Migration assay showed a remarkable increase in the activity both in P/ARK and D/ARK, and an in vivo metastasis assay showed a marked increase of P/ARK in liver metastasis. Based on these observations, it is suggested that ARK5 expression is involved in cancer invasion and metastasis.