New hepatocellular carcinoma cell line SUHC-1 established from a patient with hepatitis C virus RNA in serum

Peroxisome proliferator-activated receptor gamma ligand troglitazone induces cell cycle arrest and apoptosis of hepatocellular carcinoma cell lines

BACKGROUND

Ligand activation of peroxisome proliferator-activated receptor gamma (PPARgamma) results in the inhibition of proliferation of various cancer cells. The aim of this study is to investigate the mechanisms of cell growth inhibition of hepatocellular carcinoma (HCC) cell lines by the PPARgamma ligand, troglitazone.

METHODS

Six HCC cell lines were used to study the effects of troglitazone on cell growth by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, on cell cycle by flow cytometry, and on the cell cycle-regulating factors of late G1 phase by Western blotting. Apoptosis assays were performed by flow cytometry using membrane, nuclear, cytoplasmic, and mitochondrial markers. Caspase inhibitors were used to analyze the mechanisms of apoptosis induced by troglitazone.

RESULTS

Troglitazone showed a potent dose-dependent effect on the growth inhibition of all six HCC cell lines, which were suppressed to under 50% of control at the concentration of 10 micromol/L. The growth inhibition was linked to the G1 phase cell cycle arrest through the up-expression of the cyclin-dependent kinase inhibitors, p21 and p27 proteins, and the hypophosphorylation of retinoblastoma protein. Troglitazone induced apoptosis by caspase-dependent (mitchondrial transmembrane potential decrease, cleavage of poly [adenosine diphosphate ribose] polymerase, 7A6 antigen exposure, Bcl-2 decrease, and activation of caspase 3) and caspase-independent (phosphatidylserine externalization) mechanisms.

CONCLUSIONS

Our data suggest that ligand activation of PPARgamma by troglitazone or modified analogs of the thiazolidinedione class of drugs is a novel target for effective therapy against HCC, because of the significant antiproliferative and programmed cell death induction capabilities demonstrated by troglitazone.

Cytotoxic T lymphocyte clone specific for autologous human hepatocellular carcinoma cell line SUHC-1

We established a cytotoxic T lymphocyte (CTL) clone directed against an autologous hepatocellular carcinoma (HCC) cell line SUHC-1 which had been established in our department from a patient with HCC associated with hepatitis C virus infection. The CTL clone lysed autologous SUHC-1 cells but did not lyse autologous Epstein-Barr (EB) virus-transformed B cells, natural killer (NK) cell-sensitive erythroleukaemia cell line K562, the NK-resistant B cell line Daudi, or allogeneic HCC cell lines, Hep-G2, Hep-3B, Mahlavu and PLC/PRF/5. The CTL clone expressed CD3 and CD8 molecules. The cytotoxic activity of the clone was inhibited by anti-CD3, anti-CD8 and anti-histocompatibility antigen (HLA) class I monoclonal antibodies. These results indicated that the CTL clone recognized HCC tumour antigen in an HLA class I-restricted manner. Furthermore, we investigated the T cell receptor (TCR) gene usage of the CTL clone. The CTL clone expressed TCR alphabeta. We searched for expression of TCR variable (V) alpha and beta regions and sequenced complementary determining region (CDR) 3 of the clone. The clone expressed V alpha14, junctional (J) region alpha9.7 and V beta7, J beta2.1. The amino acid sequence of the N region of the of chain was S-P-G-G-G-G-A-D-G-L-T and of the N-D-N region of the beta chain was S-W-T-G-A-S-T-D-T-Q-Y. These results suggested that HLA class I-restricted CTL play an important role in the elimination of human HCC cells.

A childhood fibrolamellar hepatocellular carcinoma with increased aromatase activity and a near triploid karyotype

We report a 15-year-old boy with hepatocellular carcinoma (HCC) of the fibrolamellar type. He presented with advanced disease and a non-resectable tumor. Clinical features included marked gynecomastia which had been present for 3 years, failure to enter puberty, and failure to thrive. These features might have been due to a high aromatase activity of the tumor. The course of the illness suggested that the tumor had been present for at least 3 years prior to diagnosis. At diagnosis the patient had multiple metastases which included infiltrated ascites. Cytogenetic analysis of the ascites revealed a near triploid karyotype with cell-to-cell variation and an abnormality of chromosome 1 q. This to our knowledge is the first karyotype report of fibrolamellar HCC in a child.

Report of a complex karyotype in recurrent metastatic fibrolamellar hepatocellular carcinoma and a review of hepatocellular carcinoma cytogenetics

Metastatic fibrolamellar hepatocellular carcinoma (HCC) was detected in the abdominal lymph nodes of an adolescent male after resection of the primary tumor. No dividing cells were isolated from attempted cytogenetic studies of the primary tumor. However, cytogenetic analysis of lymph node metastases detected 9 and 12 months after partial hepatectomy revealed abnormal hypertriploid karyotypes, with a suggestion of clonal evolution: 62-92 < 3n >,XX, -Y, +3, +6, +6, +7, +7, +8, +10, +13, +15, +16, +20, -21, -22, +mar1 x 2, +mar[cp6]/46,XY[8] and 78 < 3n >,XX, -Y,der(1)t(1;1)(p36.1;q21), +4, +6, +6, +7, +7,i(8)(q10), +10, +15, +20, -21, -22, +mar1 x 2, +mar2[3]/46, XY[17], respectively. Karyotypes of this variant of HCC have not been reported previously. The cytogenetics of HCC are reviewed.

Persistence of hepatitis C virus RNA in established human hepatocellular carcinoma cell lines

The persistence of the viral RNA of hepatitis C virus (HCV) was examined in 13 hepatocellular carcinoma (HCC) and two hepatoblastoma cell lines by reverse transcription followed by the polymerase chain reaction (RT-PCR). HCV RNA was detected in three HCC lines (JHH-1, JHH-4, and JHH-6) and negative-strand viral RNA was found in JHH-4, indicating that there is a putative replicative intermediate of HCV in JHH-4 cells. To rule out the possibility of contamination, the partial nucleotide sequences of HCV-specific PCR products of these three cell lines were determined. The clone from JHH-1 belonged to genotype 1 (1a or 1b), and the clones from JHH-4 and JHH-6 belonged to genotype 2b, but their sequences differed from each other. These cell lines may be useful for studies related to HCV.

Establishment of Epstein-Barr virus-associated lymphoma cell line SUBL with t(2;3)(p11;q27) from a liver transplant patient

A new lymphoma cell line, designated SUBL, was established from a Japanese patient with Epstein-Barr virus (EBV)-associated lymphoma, which developed during FK 506 therapy after liver transplantation. This cell line has undergone 80 passages over a period of 22 months. The cultured cells were positive for CD19, CD20, CD21, CD22, CD23, and HLA-DR, and negative for CD10 and surface immunoglobulins. Immunoglobulin gene analysis revealed rearrangements of JH and JK. T-cell antigens or T-cell receptor gene rearrangements were not observed on the cell line. The SUBL cells were positive for Epstein-Barr virus nuclear antigen (EBNA). The EBV genome was detected in the original tissue and the cell line by the in situ hybridization method. These data indicate that this cell line represents the B-cell lineage at a pre-B-cell stage. SUBL cells showed successful heterotransplantation to mice with severe combined immunodeficiency (SCID). Chromosomal analysis revealed the karyotype 46,XY,t(2;3)(p11;q27). Molecular studies showed that c-myc, N-myc, and bcl-2 were not rearranged. This cell line will provide a useful in vitro system to study the relationship between chromosomal abnormalities and the activation of cellular oncogenes.

Immunological responses against an autologous human hepatocellular carcinoma cell line

We performed a detailed analysis of immune responses in a hepatocellular carcinoma (HCC) cell line and effector cells obtained from a patient with HCC. We examined the cytotoxic activity of natural killer (NK) cells, lymphokine-activated killer (LAK) cells and cytotoxic T lymphocytes (CTL) against an autologous tumour cell line (SUHC-1) to investigate the immune mechanism of human lymphocytes against HCC cells. Cytotoxic T lymphocytes were induced by co-culturing of peripheral blood lymphocytes (PBL) and SUHC-1 cells, mixed lymphocyte and tumour cell culture (MLTC). The susceptibility of SUHC-1 to NK and LAK cells was similar to that of other allogeneic cell lines, such as K562, PLC/PRF/5 and Mahlavu. Effector cells induced in the primary MLTC had high cytotoxic activity but were not specific for SUHC-1. Cytotoxic T lymphocytes with specific activity against SUHC-1 were induced after PBL were stimulated five times at 7-10 day intervals with SUHC-1 and low-dose recombinant interleukin-2 (rIL-2), suggesting that as the culture progressed, broadly reactive effector cells disappeared and specific effector cells survived. The specific effector cells were identified as CD3+/CD4+ and CD3+/CD8+ T-lymphocyte subsets. The recognition mechanisms of CD3+/CD4+ CTL remain unresolved because the cytotoxicities were not inhibited by anti-CD4 and anti-major histocompatibility complex (MHC) class II monoclonal antibodies (MoAb). Treatment of cells with anti-CD3, anti-CD8 and anti-MHC class I MoAb partially inhibited lysis. These results demonstrated that the T-cell receptor (TCR)/CD3 complex appeared to be involved in SUHC-1 specific antigen recognition and antigen recognition of CD3+/CD8+ CTL was MHC class I restricted.