Hiwi Promotes the Proliferation of Colorectal Cancer Cells via Upregulating Global DNA Methylation.
Hiwi is well known for its role in stem cell renewal, maintaining the resting stage, and downregulating cell cycle of stem cells via RNA silencing. And Hiwi overexpression has been recognized in several types of cancers. In the present study, we examined the Hiwi expression in colorectal cancer (CRC) specimens in both mRNA and protein levels via real-time quantitative PCR, western blot assay, and immunohistochemical staining. Then we explored the role of Hiwi in the cancer cell proliferation and in the DNA methylation in human CRC Caro-2 and HT-29 cell lines. Results demonstrated that both mRNA and protein levels of Hiwi were significantly higher in 38 CRC tissues than in 38 peritumor tissues. Moreover, the Hiwi overexpression with an adenovirus vector significantly promoted the proliferation of Caro-2 and HT-29 cells, associated with significant increase in the global DNA methylation levels. And the chemical inhibition of DNA methylation significantly restrained such proliferation promotion. In summary, we confirmed that Hiwi was overexpressed in CRC tissues and that the forced Hiwi overexpression promoted the proliferation and global DNA methylation of CRC cell lines. Our results imply for the first time that Hiwi promotes the proliferation of CRC cells via promoting global DNA methylation.
Department of Radiology, Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.
Lin
L
Yang
Department of Radiology, Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.
Lei
L
Bi
Department of Radiology, Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.
Qingwei
Q
Liu
Department of Radiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, China.
Meng
M
Zhao
Department of Gastroenterology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, China.
Bin
B
Cao
Department of Radiology, Tai'an Tumor Hospital, Taian 271000, China.
Dong
D
Li
Department of Radiology, Provincial Hospital Affiliated to Shandong University, Jinan 250021, China.
Jianjun
J
Xiu
D000328:Adult; D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D019073:HT29 Cells; D006801:Humans; D008297:Male; D008875:Middle Aged; D015854:Up-Regulation
D060565:Argonaute Proteins; C421088:PIWIL1 protein, human