Hypermethylation-mediated tumor suppressor gene silencing plays a crucial role in
tumorigenesis. Understanding its underlying mechanism is essential for
cancer treatment. Previous studies on human
N-alpha-acetyltransferase 10,
NatA catalytic subunit (hNaa10p; also known as human arrest-defective 1 [hARD1]), have generated conflicting results with regard to its role in
tumorigenesis. Here we provide multiple lines of evidence indicating that it is oncogenic. We have shown that hNaa10p overexpression correlated with poor survival of human
lung cancer patients. In vitro, enforced expression of hNaa10p was sufficient to cause cellular transformation, and
siRNA-mediated depletion of hNaa10p impaired
cancer cell proliferation in colony assays and xenograft studies. The oncogenic potential of hNaa10p depended on its interaction with
DNA methyltransferase 1 (DNMT1). Mechanistically, hNaa10p positively regulated DNMT1 enzymatic activity by facilitating its binding to
DNA in vitro and its recruitment to promoters of tumor suppressor genes, such as
E-cadherin, in vivo. Consistent with this, interaction between hNaa10p and DNMT1 was required for
E-cadherin silencing through promoter CpG methylation, and
E-cadherin repression contributed to the oncogenic effects of hNaa10p. Together, our data not only establish hNaa10p as an
oncoprotein, but also reveal that it contributes to
oncogenesis through modulation of DNMT1 function.