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Transformation of benign Barrett's epithelium by repeated acid and bile exposure over 65 weeks: A novel in vitro model
Author(s) -
Das Kiron M.,
Kong Yingxin,
Bajpai Manisha,
Kulkarni Diptee,
Geng Xin,
Mishra Pravin,
Banerjee Debabrata,
Hirshfield Kim
Publication year - 2010
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.25343
Subject(s) - malignant transformation , telomerase , cell culture , in vitro , telomerase reverse transcriptase , biology , microbiology and biotechnology , dysplasia , pathology , cancer research , medicine , gene , biochemistry , genetics
The mechanism by which gastroesophageal reflux promotes metaplasia→dysplasia→carcinoma is unknown. The aim of the study is to determine if repeated exposure to acid and bile confers a tumorigenic phenotype in a telomerase (hTERT)‐immortalized benign Barrett's cell line (BAR‐T). BAR‐T cells were exposed to acid (pH 4) (A) and bile salt (200 μM glycochenodeoxycholic acid) (B) daily for 5 min up to 65+ weeks. The control cells were grown in parallel without any A or B treatment. Cell morphology, proliferation, transformation, and molecular changes in the gene expression for COX‐2, TC22, p53 and p53 target genes were analyzed at 8–12 weeks intervals. At 46 weeks BAR‐T cells exposed to (A+B) showed distinct phenotypic changes: forming clusters and acini, and at 65 weeks displayed foci in monolayer, and formed distinct colonies in soft agar. Untreated cells did not show any such changes. In A+B–treated BAR‐T cells, COX‐2 mRNA increased 10‐ to 20‐fold, TC22 mRNA increased by 2‐ to 3‐fold at 22–65 weeks, p53, MDM2, PERP, and p21mRNA increased 2.5‐, 6.4‐, 4‐, and 2.6‐fold respectively when compared to untreated cells at 34 weeks. However, at 58 weeks onward, there was a sharp decline of p53 and its target genes to the baseline level. At 65 weeks A+B–treated BAR‐T cells formed tumor in nude mice whereas untreated cells did not. We demonstrate a novel in vitro model of transformation of a benign Barrett's cell line following repeated exposure to A+B over the course of 65 weeks.