title: DOC45, a novel DNA damage-regulated nucleocytoplasmic ATPase that is overexpressed in multiple human malignancies.
abstract: In this article, we report the characterization of a novel DNA damage-regulated gene, named DNA damage-regulated overexpressed in cancer 45 (DOC45). Our results indicate that DNA damage-inducing agents, including doxorubicin (adriamycin), etoposide, and ionizing and UV radiation, strongly downregulate DOC45 expression, whereas endoplasmic reticulum stress-inducing agents do not. Our results also indicate that DOC45 is overexpressed in several human malignancies, including cancers of the colon, rectum, ovary, lung, stomach, and uterus. DOC45 harbors conserved nucleotide triphosphate-binding motifs and is capable of ATP hydrolysis, findings that highlight its function as a novel ATPase. Although predominantly cytoplasmic, DOC45 exhibits a characteristic nucleocytoplasmic distribution and, on inhibition of nuclear export, predominantly accumulates in the nucleoli. These results suggest that DOC45 may shuttle between nucleus and cytoplasm to carry out its function. Our results also indicate that DOC45 expression is enhanced during oncogenic Ras-mediated transformation and that its expression is linked to phosphoinositide 3-kinase signaling pathway. Furthermore, short hairpin RNA-mediated knockdown of DOC45 in human colon cancer cells inhibits their proliferation and enhances cellular sensitivity to doxorubicin-induced cell death, suggesting that DOC45 plays an important role in cell proliferation and survival. Collectively, our results indicate that DOC45 is a novel ATPase that is linked to cellular stress response and tumorigenesis, and may also serve as a valuable tumor marker.
authors.affiliation: Department of Pharmacology, State University of New York, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Sun
authors.forename: Xiuquan
authors.initials: X
authors.lastname: Luo
authors.forename: JoAnne
authors.initials: J
authors.lastname: Montalbano
authors.forename: Weixin
authors.initials: W
authors.lastname: Jin
authors.forename: Jingxue
authors.initials: J
authors.lastname: Shi
authors.forename: M Saeed
authors.initials: MS
authors.lastname: Sheikh
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D000595:Amino Acid Sequence; D014408:Biomarkers, Tumor / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000235:genetics; D019204:GTP-Binding Proteins; D015972:Gene Expression Regulation, Neoplastic; D019073:HT29 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000302:isolation & purification; D009369:Neoplasms / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D000251:Adenosine Triphosphatases; D019204:GTP-Binding Proteins; C522732:OLA1 protein, human