Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0019204 (hepatocellular carcinoma)
 71,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The roles of lymphoid elements and apoptosis-related proteins in the development of extremely large hepatomas were studied in rats. Hepatoma cells were inoculated subcutaneously into 6-week-old rats, and 4 months later the quantities of T and B cells, macrophages, and cells positive for Fas, Fas ligand (FasL) and interleukin-2 (IL-2) were immunochemically evaluated in tumors. Grafting of hepatoma cells caused the development of giant tumors that could reach one-third of the rat's body weight. Within the hepatomas, almost all CD8(+) T cells were destroyed as they passed from the tumoral stroma into the parenchyma and came in contact with tumor epithelial cells. This could be the consequence of IL-2 production, since about 90% of tumor cells were CD25(+). The tumoral mass increased despite the significant increase in tumor necrosis. Cells with Ki67 or in mitosis, and cells positive for Fas and FasL were found only among tumor epithelial cells that were necrotic and never among viable cells. We suggest that progress in tumorigenesis is facilitated by inhibition of T helper cells, and the extensive death of T killer cells is caused by the high levels of the tumor produced IL-2.
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PMID:Tumor-induced insufficiency in T cell activity and hyperproduction of interleukin-2 in rat giant hepatomas. 1117 6

We have previously reported several CTL epitopes derived from the hepatitis B viral X Ag (HBx). In this study, we evaluated whether HBx-specific CTLs can be effectively used in adoptive cancer immunotherapy. To validate the possibility, four peptides containing a HLA-A2.1-restricted binding consensus motif were identified from the HBx protein and tested for their ability to activate CTL from PBMCs isolated from chronic carriers of HBV (n = 12). We selected two highly potent epitopes, HBx 52-60 (HLSLRGLFV) and HBx 115-123 (CLFKDWEEL), that are capable of inducing Ag-specific cytotoxic T cells in patient PBMCs. For adoptive immunotherapy using HBx-specific CTLs, we generated CTL clones restricted to the HBx 52-60 or HBx 115-123 peptide using a limiting dilution technique. LC-46, an HBx 52-60-specific clone, is CD62L(-)CD69(+)CD45RO(+)CD45RA(-)CD25(dim) and is stained by IFN-gamma (approximately 92%), IL-2 (30%), and TNF-alpha (56%), but not by IL-5, IL-10, IL-12, or TNF-beta, indicating that the cells are fully activated T cytotoxic 1-type cells. When LC-46 cells were adoptively transferred into xenografted nude mice bearing human hepatomas expressing HLA-A2.1 molecules and intracellular HBx proteins, the tumors were eradicated. Taken together, our data provide solid evidence for the feasibility of adoptive immunotherapy with HBx-sensitized CTLs in hepatitis disease, including hepatocellular carcinoma (HCC).
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PMID:Tumor eradication by hepatitis B virus X antigen-specific CD8+ T cells in xenografted nude mice. 1253 74

Hepatocellular carcinoma (HCC) has a poor prognosis with limited therapeutic options. We propose that local immune responses in patients with HCC are held in check by tumor-infiltrating CD4(+)CD25(+) T-regulatory lymphocytes (T(reg) cells), which suppress the activity and proliferation of effector CD4(+) and CD8(+) T cells. The phenotype and cell cycle status of tumor-infiltrating lymphocytes (TILs) in HCC were analyzed via immunohistochemistry of sections from patients undergoing surgery for HCC and via flow cytometry of peripheral blood mononuclear cells and TILs isolated from patients with HCC. Circulating and tumor-infiltrating T-cell function and activation status were assessed via proliferation and flow cytometry. More than 96% of TILs were quiescent as measured via Mcm-2 or Ki-67 expression, while less than 10% of CD8(+) T cells expressed perforin or granzyme B. CD4(+)CD25(+) T(reg) cells comprised 8.7% (1.4-13.8) of TILs and always exceeded the proportion in distant nontumor tissue (2.4% [1.5-5.6]; P = .014). T(reg) cells isolated from HCC suppressed proliferation of autologous circulating CD4(+)CD25(-) cells and perforin expression and proliferation of autologous CD8(+) T cells. The proportion of circulating T(reg) cells in patients with HCC was similar in healthy controls (7.2% [1.2-23.3] and 9.2% [1.6-30.2], respectively), but the proportion of circulating T(reg) cells that were also transforming growth factor beta1(+) was elevated in HCC compared with controls (55.5% [8.2-73.9] and 2.0% [0-4.9], respectively; P = .003). In conclusion, TILs are compromised and contain a subpopulation of suppressive CD4(+)CD25(+)Foxp3(+) T(reg) cells. Functional deletion of tumor-infiltrating T(reg) cells could enhance tumor-specific immunotherapy.
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PMID:Compromised lymphocytes infiltrate hepatocellular carcinoma: the role of T-regulatory cells. 1578 65

We used SEREX technology to identify novel tumour-associated antigens in patients with primary hepatocellular carcinoma and found serological responses to the polycomb group (PcG) protein BMI-1, which is overexpressed in a range of different tumour types. Further studies identified T-cell responses to both BMI-1 and another PcG protein, EZH2, in cancer patients and at relatively lower levels in some normal donors. We next identified several CD8+ T-cell epitopes derived from BMI-1 and EZH2 and demonstrated that EZH2-derived peptides elicited more significant interferon-gamma (IFN-gamma) release than BMI-1-derived peptides. That CD8(+) T cells were responsible for the observed responses was confirmed for EZH2 by both IFN-gamma capture assays and tetramer staining using an HLA-A0201-restricted, EZH2-derived YMSCSFLFNL (aa 666-674) epitope. The ability of YMSCSFLFNL (aa 666-674) to stimulate the in vitro expansion of specific T cells from peripheral blood lymphocytes was greatly enhanced when the CD25(+) T-cell population was depleted. EZH2-specific cytotoxic T lymphocyte clones specific for two HLA-A0201 epitopes were generated and found to recognise endogenously processed EZH2 in both HLA-matched fibroblasts and tumour cell lines. Given the widespread overexpression of PcG proteins in cancer and their critical role in oncogenesis, these data suggest that they may be useful targets for cancer immunotherapy.
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PMID:The polycomb group proteins, BMI-1 and EZH2, are tumour-associated antigens. 1702 27

Dysfunction of the host immune system in cancer patients can be due to a number of factors, including suppression of tumor-associated antigen reactive lymphocytes by CD4(+)CD25(+) regulatory T (Treg) cells. Several studies suggest that Tregs are elevated in cancer patients and that depletion of Tregs may enhance the antitumor immunity of host, but the pathogenic and mechanistic relationship between cancer and Tregs is still unclear. In this report, we show that Tregs are increased in peripheral blood mononuclear cells (PBMCs) from hepatocellular carcinoma (HCC) patients and positively correlate with tumor burden. When PBMCs are co-cultured with human hepatoma cell lines Huh7, HepG2, and Hclone5, CD4(+)CD25(+)-T cell populations increase in frequency and undergo phenotypic and functional changes. CD45RA, CD45RO, CD69, CD62L, GITR, CTLA-4, Ki67, granzyme A, granzyme B, and FOXP3 expression were upregulated in CD4(+)CD25(+) cells after in vitro exposure to HCC cell lines. CD4(+)CD25(+) T cells from PBMCs that were co-cultured with Huh7 cells also have higher suppressor ability compared to that of the CD4(+)CD25(+) T cells from control PBMC. Huh7 culture supernatants appear to promote CD4(+)CD25(+) T-cell proliferation and inhibit CD4(+)CD25(-) T-cell proliferation. In conclusion, these results strongly suggest that tumor-related factors not only induce and expand CD4(+)CD25(+) cells, but also enhance their suppressor ability.
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PMID:Hepatocellular carcinoma cell supernatants increase expansion and function of CD4(+)CD25(+) regulatory T cells. 1737 88

Balance between effector T cells (Teff) and regulatory T cells (Treg) appears to be very crucial for effective anti-tumor immunotherapy. The therapeutic efficacies of enhancement of Teff and suppression of Treg were compared between two murine hepatoma cell lines of a similar origin, MH129 and MH134. Enhancement of Teff was achieved by infection of tumor cells with adenovirus expressing glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), and suppression of Treg, by depletion of CD4+CD25+ naturally occurring Treg by administration of anti-CD25 monoclonal antibody (PC61) or low-dose cyclophosphamide. Our data show that MH129 cells were susceptible to Treg depletion but resistant to GITR expression, and vice versa for MH134 cells. Thus, in MH129 cells, injection of PC61 prior to or after tumor cell inoculation completely or partially, respectively, eradicated tumor growth. Low-dose cyclophosphamide administered after tumor cell inoculation also delayed tumor growth. However, GITR expression either in vitro or in vivo exhibited little effect. In contrast, in MH134 cells, PC61 induced partial tumor growth delay only when injected prior to tumor cell inoculation, and low-dose cyclophosphamide showed no effect, but GITR, particularly when administered in vitro, inhibited tumor growth. An additive effect of PC61 and GITR was observed only in MH134 cells. The ratios of peripheral CD4+CD25+ to CD4+ T cells remained unaltered during the experimental course in both tumor models. From these results we speculate that this different sensitivity may be due to a difference in relative induction levels of Teff versus Treg, not due to different immunogenicity or different kinetics of peripheral Treg, between the two tumor models. Future studies identifying antigen(s) or epitope(s) specific for Teff and Treg in these tumor cell lines are necessary as analysis of the immune response to such antigen(s) or epitope(s) may in general help predict the relative efficacy of different immunotherapies against distinct tumors.
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PMID:Distinct responses of two hepatocellular carcinoma cell lines of a similar origin to immunotherapies targeting regulatory or effector T cells. 1739 75

Tumor cells may escape from the immune responses because of defective differentiation of dendritic cells (DC). Recent studies have found an increased number of regulatory T cells (Treg) in both peripheral blood and tissues from patients with hepatocellular carcinoma. In the present study, we used tumor culture supernatants (TSN) from hepatoma-derived cell lines to investigate whether TSN interfere with the differentiation of human monocyte-derived DC and/or their ability to increase Treg. The results showed that exposure to TSN significantly inhibited the differentiation of monocytes into DC with retained CD14 molecule and reduced expression of CD1a. These TSN-exposed immature DC also produced significant amount of immunosuppressive cytokine IL-10 and displayed an increased expression of co-stimulatory molecules. Upon stimulation with LPS, however, the TSN-exposed DC failed to undergo full maturation, with a blockage of the upregulation of co-stimulatory molecules on their surface and a switch to an IL-10(high)IL-12(low)TNF-alpha(low) phenotype. Moreover, exposure of DC to TSN selectively inhibited their capacity to stimulate the proliferation of allogeneic CD8(+) T cells, but promoted the generation of CD4(+)CD25(hi)Foxp3(+) Treg cells. These findings, together with previous clinical studies showing that CD4(+)CD25(hi) Treg cells are concentrated within hepatocellular carcinoma tissue, suggest that the local tumor microenvironment may favor the induction of Treg cells through inhibiting the differentiation and maturation of DC.
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PMID:Hepatoma cells inhibit the differentiation and maturation of dendritic cells and increase the production of regulatory T cells. 1794 51

Both hepatitis B virus (HBV) and hepatitis C virus (HCV) can cause persistent viral infection in humans. Chronic infection is associated with a risk of cirrhosis and hepatocellular carcinoma. The cause of chronic infection is unknown. A large body of evidence suggests that a failure of the adaptive immune response is critical in the establishment of chronic infection. Recently a new group of T cells (T-regulatory cells), that express CD4(+)CD25(+) and Foxp3, which can inhibit the cellular (CD4(+)/CD8(+)) immune response have been described. In this review the authors explore the thoughts regarding immune responses to HBV and HCV infections and the role of these T-regulatory cells in relation to the pathogenesis of chronic HBV and HCV infection and the potential for therapeutic intervention.
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PMID:T-regulatory lymphocytes and chronic viral hepatitis. 1796 Oct 92

Functional defects in natural killer (NK) cells have been proposed to be responsible for the failure of anti-tumor immune responses. Whether and how NK cells are impaired in hepatocellular carcinoma (HCC) patients remain unknown. In this study, we found that HCC patients displayed a dramatic reduction in peripheral CD56(dim)CD16(pos) NK subsets compared with healthy subjects. A significant reduction of CD56(dim)CD16(pos) NK subsets was also found in tumor regions compared with non-tumor regions in the livers of these HCC patients. Both these peripheral and tumor-infiltrating NK cells exhibited poorer capacity to produce IFN-gamma and kill K562 targets, which was further found to be associated with increased CD4(+)CD25(+) T regulatory cells as we previously-described in HCC patients. Addition of Tregs from HCC patients efficiently inhibited the anti-tumor ability of autologous NK cells in vitro. These findings are helpful for understanding the mechanism of NK cell-mediated anti-tumor immune responses in HCC patients.
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PMID:Functional impairment in circulating and intrahepatic NK cells and relative mechanism in hepatocellular carcinoma patients. 1882 14

Hepatitis C chronic infection occurs in 80% of the cases and eventually leads to cirrhosis and hepatocellular carcinoma. A deficient adaptive immune response has been described during chronic infection which contributes to viral persistence. This altered T cell response could be associated to deficient costimulation signals during priming of T cells. We have conducted an in vitro study to explore the activation phenomenon of CD4+ T cells focusing on costimulation via the CD28 receptor, associated to stimulation with purified Hepatitis C (HCV) core antigen. Our study involved the induction of CD69, CD25 and CD40L activation receptors, along with detection of intracellular cytokines such as IFN-gamma, TGF-beta and IL-10. Analysis was performed in chronically HCV infected patients, intrafamilial members of HCV-infected patients and healthy individuals. HCV core antigen induced CD40L expression in CD4+ cells from intrafamilial members, in contrast to chronically infected patients and control individuals. Association of CD28 crosslinking increased CD69 and IFN-gamma expression in chronically infected patients, suggesting a detriment in this signaling pathway. Additionally, an increased TGF-beta expression was observed in CD4+ cells from HCV-infected patients, which was corrected by addition of CD28 crosslinking. Our results may contribute to understand the underlying mechanism of T cell tolerance against HCV during chronic infection, and to provide new targets for the designing of therapeutic strategies to control the infection and to offer protective immunity against the virus.
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PMID:[Impaired activation and costimulation of T CD4+ lymphocytes during chronic hepatitis C infection]. 1884 76


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