Frequent Overexpression of STK15/Aurora-A/BTAK and Chromosomal Instability in Tumorigenic Cell Cultures Derived From Human Ovarian Cancer
The STK15 (also known as Aurora-A/BTAK) gene localized on chromosome 20q13 and encoding a centrosome-associated serine/threonine kinase is amplified and overexpressed in multiple human tumor cell types. Overexpression of this gene is involved in tumorigenic transformation, induction of centrosome duplication-distribution abnormalities, and aneuploidy in mammalian cells. To examine the potential role of STK15 in ovarian tumorigenesis, its mRNA and protein expression status were examined in cells grown in culture from 15 ovarian cancer specimens using semiquantitative RT-PCR and Western blot analysis. Normal ovarian surface tissues and the near diploid nontumorigenic breast epithelial cell line MCF10 were used as controls. The status of STK15 correlated with transformation-associated cellular phenotypes including tumorigenicity in nude mice, p53 expression level, and chromosomal ploidy. For chromosome ploidy analyses, FISH was carried out with direct fluorescence-labeled α-satellite probes for chromosome 3 and 17. STK15 mRNA was found overexpressed in 10 of the 15 ovarian cancer cell cultures. Five of these cell cultures revealed a truncated form of the STK15 protein with a molecular mass of 36 kDa. When tested for tumorigenicity in nude mice, 9 of the 10 cell cultures that overexpressed STK15 mRNA formed tumors in nude mice, while only one of the five cell cultures with no overexpression did. Cells overexpressing STK15 mRNA showed significant correlation with chromosome 3 polysomy. Six of the 13 (46%) cell cultures analyzed for p53 expression revealed overexpression of p53 and five of these six (83%) also overexpressed STK15. Four of the remaining seven cultures (57%) with overexpression of STK15 revealed minimal or no expression of p53. These results demonstrate that overexpression of STK15 significantly correlates with nude mice tumorigenicity and chromosomal aneuploidy in human ovarian cancer cells grown in vitro. Additionally, cells overexpressing STK15 also revealed frequent coordinate loss of wild-type p53 function manifested either as highly expressed intense staining reflective of a mutant form of p53 or almost complete absence of p53 staining. Overexpression of STK15 with coordinate loss of wild-type p53 function thus appears to play an important role in ovarian tumorigenesis and offers a novel molecular target in designing effective therapy of human ovarian cancer.
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Document Type: Research Article
Department of Gynecologic Medical Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
Department of Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
Department of Biomathematics, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
Department of Gynecology Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
Experimental Therapeutics, University of New Mexico, Albuquerque, NM 87131
Department of Molecular Pathology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030
Publication date: January 1, 2005
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Formerly: Oncology Research Incorporating Anti-Cancer Drug Design
Oncology Research Featuring Preclinical and Clincal Cancer Therapeutics publishes research of the highest quality that contributes to an understanding of cancer in areas of molecular biology, cell biology, biochemistry, biophysics, genetics, biology, endocrinology, and immunology, as well as studies on the mechanism of action of carcinogens and therapeutic agents, reports dealing with cancer prevention and epidemiology, and clinical trials delineating effective new therapeutic regimens.
From Volume 23, Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics is Open Access under the terms of the Creative Commons CC BY-NC-ND license.