Karyotypic characterization of an established human hepatoma cell line HA22T/VGH

A comprehensive karyotypic analysis on Korean hepatocellular carcinoma cell lines by cross-species color banding and comparative genomic hybridization

Chromosomal aberrations were investigated in hepatitis B virus integrated into the hepatocellular carcinoma (HCC) cell lines SNU-368, SNU-449, SNU-398, SNU-182, and SNU-475 using Giemsa-banding, cross species color banding, and comparative genomic hybridization (CGH). The origins of the marker chromosomes were confirmed by fluorescence in situ hybridization with constructed chromosome painting probes. Each cell line had unique modal karyotypic characteristics and showed variable numbers of numerical and structural clonal cytogenetic aberrations. The gains were commonly detected on chromosome 1, and chromosome regions 6p, 7q, 8q, 10p, 17q, and 20; the losses were often found on 4q21 approximately qter, 13, 18q21 approximately qter, and Y. In particular, the breakpoints on 1p36, 1p13 approximately q21, 2p13 approximately q11, 6q10 approximately q11, 7q11, 7q22, 14q10, 16q10 approximately q13, 17q21, 18q21, and 19p11 approximately q11 were involved frequently at the multiple rearranged lesions. CGH analysis further confirmed the cytogenetic data, and the nonrandom rearrangements data suggested the candidate regions for the genes to be isolated which were related to HCC.

Consistent chromosome 10 rearrangements in four newly established human hepatocellular carcinoma cell lines

Cancer cell lines represent an invaluable resource for isolation of novel genes relevant to tumor pathogenesis and as in vitro models. In this study, we report on the successful establishment of four cell lines from hepatocellular carcinoma tissue. These cell lines, designated HKCI-1, HKCI-2, HKCI-3, and HKCI-4, have been growing continuously for more than 24 months and have been passaged more than 50 times. A comprehensive cytogenetic characterization on the primary tumors and the derived cell lines was achieved by the combined approach of spectral karyotyping and comparative genomic hybridization. Chromosomal imbalances from the primary tumors were also maintained in the cell lines and included gains of 1q, 6p, 7, 10p, 17q, and 20 and loss of 4q. Recurring translocations included t(X;11), t(1;10), t(4;16), i(5)(p10), t(7;21), t(8;17), t(9;22), i(10)(p10), t(14;20), t(16;22), and t(17;19). It was noteworthy that consistent chromosome 10 aberrations, in particular t(1;10)(q10;p10), were detected in all four cell lines. Furthermore, microsatellite analysis on primary tumor and derived cell lines indicated a common deleted region of 10q23-q26. The functional importance of chromosome 10 aberrations in relation to the pathogenesis of HCC is unknown; however, the high frequency with which such aberrations were maintained in the cell lines suggests proliferative advantages of 10q loss or 10p gain in the multistep development of hepatic neoplasia.

A comprehensive karyotypic analysis on a newly developed hepatocellular carcinoma cell line, HKCI-1, by spectral karyotyping and comparative genomic hybridization

A continuously growing human hepatocellular carcinoma (HCC) cell line was established from a Chinese male, carrier of the hepatitis B virus (HBV). This cell line, designated HKCI-1, grows as an adhering monolayer of polygonal epithelial cells that embody one or more nuclei. HKCI-1 secretes alpha-fetoprotein but shows no evidence of HBV carriage. Conventional banding analysis of the short-term cultured primary tumor and the propagated HKCI-1 revealed a chromosome modal number of near-triploidy. It was, however, impossible to derive their complete karyotype due to the complex nature of chromosomal rearrangements and many marker chromosomes of uncertain origin. Spectral karyotyping (SKY) is a newly developed molecular cytogenetic technique that allows the unprecedented discernment of chromosomal abnormalities. Spectral karyotyping analysis on HKCI-1 and the primary tumor elucidated all aberrant chromosomes and revealed complex karyograms. Recurring aberrations detected in both primary tumor and HKCI-1 included der(X)t(X;11)(q10;p10), der(1)t(1;10)(q10;?pq), der(4)t(4;16)(p10;q10), i(5p), del(5)(q13), der(7)t(7;21)(q32q10::q10), der(8)t(8;17)(q10;p10), and der(9)t(9;22)(q34;?pq). Comparative genomic hybridization (CGH) was employed to monitor the culture evolution in vitro. Genomic imbalances in HKCI-1 involved chromosomal losses on 4q, 5q13-qter, 8p, 9pter-q33, 10q, 11q, 13q, 16q, 17q12-qter, and 22, and low-level gains on 6pter-q22, 7p, 8q, 9q34, 10p, 11p, 12, 17pter-q11.2, 18, 19, 20, 21, and Y. High-level amplifications were also detected on 5pter-q12, 7q11.2-qter, and Xq. The corresponding CGH finding on the primary tumor indicated similar imbalances. TP53 mutational analysis showed that both HKCI-1 and the primary tumor had the aflatoxin-associated mutation in codon 249 and an additional TP53 polymorphism in codon 72. Our present study demonstrates the value of combined SKY and CGH study in defining complex rearrangements and identifying cryptic translocations, and provides a comprehensive analysis on the chromosomal abnormalities in HKCI-1.

Trisomy 1 and 8 occur frequently in hepatocellular carcinoma but not in liver cell adenoma and focal nodular hyperplasia. A fluorescence in situ hybridization study

Conventional cytogenetic studies revealed gains and structural aberrations of chromosome 1 to be the most consistent chromosomal aberrations in hepatocellular carcinoma (HCC). We investigated touch preparations of eight HCC, five cholangiocellular carcinomas (CCC), five liver cell adenomas (LCA), four focal nodular hyperplasias (FNH) as well as nine specimens of normal liver tissue using fluorescence in situ hybridization (FISH) with centromere specific probes for chromosomes 1 and 8. Polysomies of chromosome 1, especially trisomy 1, were found in five of eight HCC and four of five CCC but in no normal liver tissue or benign tumour. Only three of seven cases of HCC revealed trisomy 8 whereas the five benign liver tumours and all normal liver tissues examined had disomy 8. Our results confirm conventional cytogenetic findings in terms of chromosome 1 aberrations in HCC although they are not specific for these types of malignant liver tumours. Since alpha-satellite probes were used in our study, only gains or losses including the centromeric regions of the chromosomes 1 and 8 could be detected. Nevertheless, our findings suggest that FISH may help in the differential diagnosis of malignant versus benign neoplasms of the liver.

Cytogenetic analysis of human hepatocarcinoma cell line PLC-PRF-5 and its mutant clones with different degrees of cell differentiation

A detailed analysis was made of the karyotype of human hepatocarcinoma cell line PLC-PRF-5 containing an integrated hepatitis B viral genome and 10 mutant clones derived from the line. These clones are drug resistant and display features of cell differentiation. Cytogenetic manifestations of gene amplification common to many cells resistant to drugs were not observed in these clones, but certain tendencies of karyotype evolution involving material from chromosomes 7 and 11, as well as chromosomes 5 and 15, were recorded for a group of cytostatic-resistant clones. An increase in polyploid cell number and number of cells with chromosome pulverization as compared with the original line was noted in the clones. This phenomenon may be related to the cytopathic effect of the hepatitis B viral proteins, which have a higher expression in the clones.