Altered regulation of extrinsic apoptosis pathway in HCV-infected HCC cells enhances susceptibility to mapatumumab-induced apoptosis
Background: Hepatitis C virus (HCV)-infected patients, including those co-infected with human immunodeficiency virus (HIV), are at increased risk of developing hepatocellular carcinoma (HCC). We evaluated the ability of agonistic human monoclonal antibodies to tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptors, mapatumumab and lexatumumab, respectively, to induce TRAIL-receptor mediated apoptosis (TRMA) in HCC (HCV-infected and -uninfected) cells and in peripheral blood cells (HIV-infected and -uninfected). Methods: Susceptibility to antibody-mediated TRMA was measured by caspase 3/7 activity and by confocal microscopy. Surface expression of receptors on HCV-uninfected and -infected Huh7.5 cells was measured by flow cytometry and confocal microscopy. Inhibitor of Apoptosis Protein (IAP) RNA levels were quantified by RT-PCR. DNA Microarray was performed using RNA isolated from Huh7.5 cells (HCV-infected and uninfected) using Affymetrix U133A chips. Results: Mapatumumab preferentially induces TRMA of HCV-infected Huh7.5 cells by binding to TRAIL-R1. Higher basal expression of TRAIL-R2 compared to that of TRAIL-R1 on HCV-uninfected Huh7.5 cells were observed. Lexatumumab induces TRMA of both HCV-infected and -uninfected cells by binding to TRAIL-R2. IFN-α has minimal effect on mapatumumab- and lexatumumab-induced TRMA. HCV infection of Huh7.5 cells up-regulates TRAIL-R1 expression and X-linked Inhibitor of apoptosis protein and survivin gene expression. Neither antibody had a pro-apoptotic effect on PBMCs from patients with HIV infection ex vivo. Conclusion: Both mapatumumab and lexatumumab are excellent candidates for therapy of HCC. HCV infection of Huh7.5 cells selectively up-regulates TRAIL-R1 receptor, associated with increased susceptibility to mapatumumab-mediated TRMA. HCV infection up-regulated IAP genes, offering promise for future combination therapy using TRAIL agonists and IAP inhibitors.
[Show abstract] [Hide abstract] ABSTRACT: Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide. Interferon-alpha (IFN-α) has recently been recognized to harbor therapeutic potential in the prevention and treatment of HCC, but it remains controversial as to whether IFN-α exerts direct cytotoxicity against HCC. Cyclooxygenase-2 (COX-2) is overexpressed in HCC and is considered to play a role in hepatocarcinogenesis. Therefore, we aimed to elucidate the combined effect of a COX-2 inhibitor, celecoxib, and IFN-α on in vitro growth suppression of HCC using the hepatoma cell line HLCZ01 and the in vivo nude mouse xenotransplantation model using HLCZ01 cells. Treatment with celecoxib and IFN-α synergistically inhibited cell proliferation in a dose- and time-dependent manner. Apoptosis was identified by 4',6-diamidino-2-phenylindole dihydrochloride and fluorescent staining. IFN-α upregulated the expression of TRAIL, while celecoxib increased the expression of TRAIL receptors. The combined regimen with celecoxib and IFN-α reduced the growth of xenotransplanted HCCs in nude mice. The regulation of IFN-α- and COX-2 inhibitor-induced cell death is impaired in a subset of TRAIL-resistant cells. The molecular mechanisms of HCC cells resistant to TRAIL-induced apoptosis were explored using molecular biological and immunological methods. Interferon-α and the COX-2 inhibitor celecoxib synergistically increased TRAIL-induced apoptosis in hepatocellular carcinoma. These data suggest that IFN-α and celecoxib may offer a novel role with important implications in designing new therapeutics for TRAIL-resistant tumors. Copyright © 2015. Published by Elsevier Inc.0Comments 1Citation
- "However, some HCC cells remain resistant to TRAIL-induced apoptosis. It has been shown that the death ligand TRAIL is a critical IFN-induced apoptosis mediator in this scenario . DR4 and DR5 are the main apoptosis-inducing receptors, and the receptors have an intracellular death domain to transmit the apoptotic signal. "
[Show abstract] [Hide abstract] ABSTRACT: Apoptotic response in hepatocellular carcinoma (HCC) cells is impaired because of interconnectivity of proteins into complexes and signaling networks that are highly divergent in time and space. TNF-related apoptosis-inducing ligand (TRAIL) has emerged as an attractive anticancer agent reported to selectively induce apoptosis in cancer cells. Although diametrically opposed roles of TRAIL are reported both as an inducer of apoptosis and regulator of metastasis, overwhelmingly accumulating experimental evidence highlighting apoptosis inducing activity of TRAIL is directing TRAIL into clinical trials. Insights from TRAIL mediated signaling in HCC research are catalyzing new lines of study that should not only explain molecular mechanisms of disease but also highlight emerging paradigms in restoration of TRAIL mediated apoptosis in resistant cancer cells. It is becoming progressively more understandable that phytochemicals derived from edible plants have shown potential in modelling their interactions with their target proteins. Rapidly accumulating in vitro and in-vivo evidence indicates that phytonutrients have anticancer activity in rodent models of hepatocellular carcinoma. In this review we bring to limelight how phytonutrients restore apoptosis in hepatocellular carcinoma cells by rebalancing pro-apoptotic and anti-apoptotic proteins. Evidence has started to emerge, that reveals how phytonutrients target pharmacologically intractable proteins to suppress cancer. Target-based small-molecule discovery has entered into the mainstream research in the pharmaceutical industry and a better comprehension of the genetics of patients will be essential for identification of responders and non-responders.0Comments 3Citations
- "Wealth of information verifies the fact that Mapatumumab preferentially induces apoptosis in HCV-infected Huh7.5 cells by binding to DR4. Lexatumumab induces apoptosis in both HCV-infected and uninfected cells by binding to DR5 . Dual-regulated oncolytic adenoviral vector encoding TRAIL gene has lately been shown to be effective against liver carcinoma . "
- [Show abstract] [Hide abstract] ABSTRACT: HtrA1, a serine protease, is down-regulated in various human solid tumors. Overexpression of HtrA1 in human cancer cells inhibits cell growth and proliferation in vitro and in vivo, suggesting its possible role as a tumor suppressor. Immunohistochemistry was used to determine the expression of HtrA1 in 50 hepatocellular carcinoma specimens and adjacent liver tissues. The correlation between the expression of HtrA1 and the clinico-pathologic data were analyzed. The levels of HtrA1 were lower in tumor tissues than in their adjacent liver tissues. Moreover, an inverse relationship was found between HtrA1 expression and the differentiation of hepatocellular carcinoma. Loss of HtrA1 was more frequently found in tumors in Edmondson grade III-IV, especially in those with venous invasion, compared to tumors in Edmondson grade I-II. Most importantly, patients with higher HtrA1 expression had a better survival rate. All these data suggest an important role of HtrA1 in hepatocellular carcinoma development and progression, which may be a new target for its treatment.0Comments 17Citations