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Growth inhibition due to complementation of transforming growth factor‐β receptor type II ‐defect by human chromosome 3 transfer in human colorectal carcinoma cells
Author(s) -
Miyafuji Yasunori,
Zhong Xiaoling,
Uchida Iichiro,
Koi Minoru,
Hemmi Hiromichi
Publication year - 2001
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1084
Subject(s) - autocrine signalling , biology , transforming growth factor , growth inhibition , transforming growth factor beta , complementation , chromosome , microbiology and biotechnology , gene , cell growth , cell culture , chromosome instability , cancer research , endocrinology , genetics , mutant
The transforming growth‐β receptor type II ( TGF‐βRII ) gene is one of the target genes of the DNA mismatch repair (MMR) defect. The human colorectal carcinoma cell line HCT116 has mutations in the hMLH1 gene and in the microsatellite region of the TGF‐βRII gene, both located on the short arm of chromosome 3. Introduction of the wild‐type hMLH1 gene on transferred human chromosome 3 restores many characteristics of MMR‐deficiency in HCT116. In this study, we determined whether transfer of chromosome 3 into HCT116 also complements the TGF‐βRII gene defect. We compared in vitro growth characteristics between HCT116 and HCT116 with a transferred chromosome 3 (HCT116 + ch3). The growth was suppressed in HCT116 + ch3 compared with parental HCT116. This suppression was abolished by frequent replacement with fresh medium, suggesting that the autocrine TGF‐β‐TGF‐βRII system may be responsible for growth suppression. To explore this possibility, we determined several characteristics essential for the autocrine system. We found that HCT116 + ch3 expresses wild‐type as well as mutated TGF‐βRII mRNA. In addition, phosphorylation of TGF‐βRI and growth inhibition were observed in HCT116 + ch3 but not in HCT116 by exposure to exogenous TGF‐β. The amount of TGF‐β1 in HCT116 + ch3 cultures was remarkably less than that in the HCT116, suggesting that TGF‐β produced by HCT116 + ch3 cells may be consumed by the cells. The conditioned medium from HCT116 cultures inhibits HCT116 + ch3 growth. This inhibition was neutralized by the anti‐TGF‐β antibody. Taken together, these results strongly suggest that the TGF‐βRII gene defect in HCT116 is complemented by a wild‐type gene on the transferred chromosome 3 and that HCT116 + ch3 gained the ability to respond to TGF‐β. Simultaneous complementation of defects of a responsible gene and a major target gene by the chromosome transfer is useful to prove the inactivated phenotypes acquired during colorectal tumorigenesis. © 2001 Wiley‐Liss, Inc.