| Association of Chromosomal Alterations with Arsenite-Induced Tumorigenicity of Human HaCaT Keratinocytes in Nude Mice Chia-Wen Chien,1 Ming-Chang Chiang,2 I-Ching Ho,3 and Te-Chang Lee1,3 1Institute of Biopharmaceutical Science, National Yang Ming University, Taipei, Taiwan, Republic of China; 2Department of Life Science, National Central University, Taoyuan, Taiwan, Republic of China; 3Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, Republic of China Abstract
Inorganic arsenic is a well-documented human carcinogen. Chronic low-dose exposure to inorganic arsenic is associated with an increased incidence of a variety of cancers, including skin, lung, bladder, and liver cancer. Because genetic alterations often occur during cancer development, the objective of this study was to explore what types of genetic alterations were induced by chronic exposure of human HaCaT cells to arsenic. After 20 passages in the presence of inorganic trivalent arsenite at concentrations of 0.5 or 1 µM, HaCaT cells had higher intracellular levels of glutathione, became more resistance to arsenite, and showed an increased frequency of micronuclei. Furthermore, the previously nontumorigenic HaCaT cells became tumorigenic, as shown by subcutaneous injection into Balb/c nude mice. Cell lines derived from the tumors formed by injection of arsenite-exposed HaCaT cells into nude mice expressed higher levels of keratin 6, a proliferation marker of keratinocytes, than did parental HaCaT cells, whereas the expression of keratins 5, 8, and 10 was significantly decreased. Comparative genomic hybridization demonstrated chromosomal alterations in the 11 cell lines derived from these tumors ; all 11 showed significant loss of chromosome 9q, and seven showed significant gain of chromosome 4q. The present results show that long-term exposure to low doses of arsenite transformed nontumorigenic human keratinocytes to cells that were tumorigenic in nude mice and that chromosomal alterations were observed in all cell lines established from the tumors. Key words: arsenite, chromosomal alterations, comparative genomic hybridization, HaCaT cells, tumorigenicity. Environ Health Perspect 112:1704-1710 (2004) . doi:10.1289/ehp.7224 available via http://dx.doi.org/ [Online 27 July 2004]
Address correspondence to T.-C. Lee, Institute of Pharmaceutical Science, National Yang Ming University, Pei-Tou, Taipei 112, Taiwan, Republic of China. Telephone: 886-2-28267300. Fax: 886-2-28237583. E-mail: tclee@ym.edu.tw We thank Y.-J. Chen (Molecular Cytogenetics Laboratory) and C.-W. Chi (Molecular Pathology Laboratory, Genome Research Center, National Yang-Ming University) for their excellent technical assistance on comparative genomic hybridization and pathologic examination. This work was supported by grants from the National Science Council of Taiwan (NSC 90-2318-B-010-006-M51, 91-3112-B-010-006, 92-3112-B-010-019) . The authors declare they have no competing financial interests. Received 3 May 2004 ; accepted 27 July 2004.
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