Cytogenetic characterization of two colon cell lines by using conventionalG-banding, comparative genomic hybridization, and whole chromosome painting

The heterogenous nature of genetic alterations in cancer cells handicaps th e full characterization of its occurrence and the analysis of their molecul ar bases and relation to biological processes. Although many cancer cells a re highly aneuploid, in other cases, as in a subset of colorectal carcinoma s displaying microsatellite instability, chromosomal aberrations are scarce . The aim of this study was to fully characterize both qualitatively and qu antitatively: the karyotypes of two established colon carcinoma cell lines (LoVo and HCT 116) previously reported as being near diploid. An array of c omplementary cytogenetic techniques were used: G-banding, comparative genom e hybridization (CGH), and whole-chromosome painting (WCP). Combinations of these techniques provided an accurate karyotype for the two cell lines: Lo Vo cells showed 49,XY, t(2;12)(q13;p11.2), +5, +7,+12,i(15)(q10) and HCT 11 6 cells shelved 45,X, -Y,dup(10)(q24q26),der(16)t(8;16)(q13;p13),der(18)t(1 7;18)(q21;p11.3). Heterogeneity was also observed in both cell lines as sho wn by G-banding. Chromosomal unbalances determined by CGH (many of them rel ated to structural reorganizations) were characterized by WCP, allowing the reliable identification of those chromosome markers that could not be comp letely identified by G-banding. We show that combined analysis with classic al and molecular cytogenetic techniques provides an accurate map of chromos omal aberrations in these two cell lines not identified in previous investi gations. (C) 2000 Elsevier Science Inc. All rights reserved.