hNaa10p contributes to tumorigenesis by facilitating DNMT1-mediated tumor suppressor gene silencing
Chung-Fan Lee, … , Cheng-Wen Wu, Li-Jung Juan
Chung-Fan Lee, … , Cheng-Wen Wu, Li-Jung Juan
Published July 1, 2010
Citation Information: J Clin Invest. 2010;120(8):2920-2930. https://doi.org/10.1172/JCI42275.
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Research Article Oncology

hNaa10p contributes to tumorigenesis by facilitating DNMT1-mediated tumor suppressor gene silencing

Abstract

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-α-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.

Authors

Chung-Fan Lee, Derick S.-C. Ou, Sung-Bau Lee, Liang-Hao Chang, Ruo-Kai Lin, Ying-Shiuan Li, Anup K. Upadhyay, Xiaodong Cheng, Yi-Ching Wang, Han-Shui Hsu, Michael Hsiao, Cheng-Wen Wu, Li-Jung Juan

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Figure 2

hNaa10p contributes to clonogenesis and xenograft tumor formation in lung cancer cells.

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hNaa10p contributes to clonogenesis and xenograft tumor formation in lun...
(A) hNaa10p overexpression enhances the colony formation ability of NIH3T3 cells on soft agar. hNaa10p-V5, hNaa10p with C-terminal V5 tag (containing 14 amino acids, GKPIPNPLLGLDST, derived from the P and V proteins of the paramyxovirus of simian virus 5). Representative microscopic images of the colonies are shown. Scale bars: 100 μm. (B) Western blots showing successful knockdown of hNaa10p protein level by si-hNAA10-1 and si-hNAA10-2. si-scramble and si-Tax were used as negative controls. (C) Lung cancer H1299 cells transfected with si-hNAA10-1 exhibited poor proliferation rate compared with cells mock transfected or transfected with si-Tax. (D) Transfection with si-hNAA10-1 or si-hNAA10-2 impaired the ability of H1299 cells to form colonies on soft agar, compared with cells mock transfected or transfected with si-scramble. Photographs of representative soft agar plates are shown. (E) H1299 cells transfected with si-hNAA10-1 or si-hNAA10-2 generated smaller tumors in NOD-SCID mice than did cells mock transfected or transfected with si-scramble. The volume of the derived tumors was measured at the indicated days after injection. Representative tumor masses are shown. A total of 5–6 mice was analyzed in each group. Data in A, C, D, and E are mean ± SD from 3 independent assays.