Role of the Fas/FasL pathway in combination therapy with interferon-alpha and fluorouracil against hepatocellular carcinoma in vitro

Anti-tumor effect of avadomide in gemcitabine-resistant pancreatic ductal adenocarcinoma

PURPOSE

Although gemcitabine-based chemotherapy is most recommended for pancreatic ductal adenocarcinoma (PDAC), its effectiveness is limited because of drug resistance. Given thalidomide's anti-tumor effects in solid tumors, we investigated the effect of avadomide, a novel thalidomide analog, on PDAC and explored its anti-tumor mechanisms.

METHODS

PDAC cell lines, including gemcitabine-resistant (GR) clones derived from MiaPaCa2 cells, were used to evaluate the effects of avadomide. An annexin V assay, a cell cycle assay, and western blot analysis were performed to explain the mechanism of avadomide as an anti-tumor reagent. Moreover, we investigated the anti-tumor effect on tumor growth using a subcutaneous xenograft murine model.

RESULTS

Avadomide showed anti-tumor effects in human PDAC cell lines. The proportion of apoptotic cells and G0/G1 phase cells after avadomide treatment increased, especially in the GR PDAC clones. Western blot analysis also showed the induction of the apoptotic pathway by inhibiting the NF-κB process and G1 phase cell cycle arrest. The xenograft murine model revealed that the proportion of viable cells in the avadomide-treated group was lower than that in the untreated group.

CONCLUSION

Our findings suggest that avadomide could be a novel therapeutic option to overcome gemcitabine resistance in patients with PDAC.

Reshaping the systemic tumor immune environment (STIE) and tumor immune microenvironment (TIME) to enhance immunotherapy efficacy in solid tumors

The development of combination immunotherapy based on the mediation of regulatory mechanisms of the tumor immune microenvironment (TIME) is promising. However, a deep understanding of tumor immunology must involve the systemic tumor immune environment (STIE) which was merely illustrated previously. Here, we aim to review recent advances in single-cell transcriptomics and spatial transcriptomics for the studies of STIE, TIME, and their interactions, which may reveal heterogeneity in immunotherapy responses as well as the dynamic changes essential for the treatment effect. We review the evidence from preclinical and clinical studies related to TIME, STIE, and their significance on overall survival, through different immunomodulatory pathways, such as metabolic and neuro-immunological pathways. We also evaluate the significance of the STIE, TIME, and their interactions as well as changes after local radiotherapy and systemic immunotherapy or combined immunotherapy. We focus our review on the evidence of lung cancer, hepatocellular carcinoma, and nasopharyngeal carcinoma, aiming to reshape STIE and TIME to enhance immunotherapy efficacy.

Bacteroides acidifaciens in the gut plays a protective role against CD95-mediated liver injury

The intestinal flora plays an important role in the development of many human and animal diseases. Microbiome association studies revealed the potential regulatory function of intestinal bacteria in many liver diseases, such as autoimmune hepatitis, viral hepatitis and alcoholic hepatitis. However, the key intestinal bacterial strains that affect pathological liver injury and the underlying functional mechanisms remain unclear. We found that the gut microbiota from gentamycin (Gen)-treated mice significantly alleviated concanavalin A (ConA)-induced liver injury compared to vancomycin (Van)-treated mice by inhibiting CD95 expression on the surface of hepatocytes and reducing CD95/CD95L-mediated hepatocyte apoptosis. Through the combination of microbiota sequencing and correlation analysis, we isolated 5 strains with the highest relative abundance, Bacteroides acidifaciens (BA), Parabacteroides distasonis (PD), Bacteroides thetaiotaomicron (BT), Bacteroides dorei (BD) and Bacteroides uniformis (BU), from the feces of Gen-treated mice. Only BA played a protective role against ConA-induced liver injury. Further studies demonstrated that BA-reconstituted mice had reduced CD95/CD95L signaling, which was required for the decrease in the L-glutathione/glutathione (GSSG/GSH) ratio observed in the liver. BA-reconstituted mice were also more resistant to alcoholic liver injury. Our work showed that a specific murine intestinal bacterial strain, BA, ameliorated liver injury by reducing hepatocyte apoptosis in a CD95-dependent manner. Determination of the function of BA may provide an opportunity for its future use as a treatment for liver disease.

Serum exosomal miR-638 is a prognostic marker of HCC via downregulation of VE-cadherin and ZO-1 of endothelial cells

Hepatocellular carcinoma (HCC) is the second leading cause of cancer‐related death. High recurrence rates after curative resection and the lack of specific biomarkers for intrahepatic metastases are major clinical problems. Recently, exosomal microRNAs (miRNAs) have been reported to have a role in the formation of the pre‐metastatic niche and as promising biomarkers in patients with malignancy. Here we aimed to clarify the molecular mechanisms of intrahepatic metastasis and to identify a novel biomarker miRNA in patients with HCC. A highly intrahepatic metastatic cell line (HuH‐7M) was established by in vivo selection. HuH‐7M showed increased proliferative ability and suppression of apoptosis and anoikis. HuH‐7M and the parental cell (HuH‐7P) showed the similar expression of epithelial‐mesenchymal transition markers and cancer stem cell markers. In vivo, mice treated with exosomes derived from HuH‐7M showed increased tumorigenesis of liver metastases. Exosomes from HuH‐7M downregulated endothelial cell expression of vascular endothelial‐cadherin (VE‐cadherin) and zonula occludens‐1 (ZO‐1) in non‐cancerous regions of liver and increased the permeability of FITC‐dextran through the monolayer of endothelial cells. The miRNAs (miR‐638, miR‐663a, miR‐3648, and miR‐4258) could attenuate endothelial junction integrity by inhibiting VE‐cadherin and ZO‐1 expression. In patients with HCC, higher serum exosomal miR‐638 expression was associated with tumor recurrence. In conclusion, the miRNAs secreted from a highly metastatic cancer cell can promote vascular permeability via downregulation of endothelial expression of VE‐cadherin and ZO‐1. Serum exosomal miR‐638 expression holds potential for serving as a significant and independent prognostic marker in HCC.

Viral elimination is essential for improving surgical outcomes of hepatitis C virus-related hepatocellular carcinoma: Multicenter retrospective analysis

AIM

The impact of sustained virologic response (SVR) on surgical outcomes for patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) remains controversial. This study aimed to evaluate the influence of SVR on long-term surgical outcomes after hepatectomy.

METHODS

This multicenter study included 504 patients who underwent curative resection for HCV-related HCC. Patients with a history of HCC treatment, HBV infection, poor liver function, and tumor with major vascular invasion were excluded. Long-term surgical outcomes (overall survival [OS] and recurrence-free survival [RFS]) among patients who achieved SVR before hepatectomy (Pre-SVR group: 58 patients), after hepatectomy (Post-SVR group: 54 patients), and without SVR (Non-SVR group: 186 patients) were compared after adjusting for 13 confounding factors. Using the surgically resected specimens, comparison of the pathological changes in liver fibrosis between the first and second hepatectomy were analyzed.

RESULTS

Patients with SVR were younger, had better liver function, and less liver fibrosis compared to patients without SVR. Propensity score-matched OS and RFS were significantly better in Pre-SVR group than Non-SVR group (P = .029 and P = .009, respectively). Inverse probability-weighted OS and RFS were also significantly better in the Post-SVR group (P = .001 and P = .021, respectively) than in the Non-SVR group. Histopathological evaluation revealed that only the patients with SVR had regression of liver fibrosis (P < .05).

CONCLUSION

Achievement of SVR before or after hepatectomy is essential for improving long-term surgical outcomes in patients with HCV-related HCC.

Impact of CD36 on Chemoresistance in Pancreatic Ductal Adenocarcinoma

BACKGROUND

CD36, a multi-ligand scavenger receptor, has been associated with several cancers. Many studies have revealed that CD36 contributed to cancer malignancy. This study aimed to reveal the function of CD36 expression in pancreatic ductal adenocarcinoma (PDAC).

METHODS

CD36 expression was characterized using immunohistochemistry in 95 clinical specimens resected from patients with PDAC. We divided patients into two groups, with different CD36 expression levels, and analyzed and compared their prognoses. CD36 expression was also assessed in PDAC cell lines. Gemcitabine-resistant (GR) PDAC cell lines were transfected with small interfering RNA (siRNA) that specifically targeted CD36 to evaluate chemoresistance and apoptosis.

RESULTS

In resected PDAC samples, CD36 expression was significantly correlated with microinvasion into the venous system (p = 0.0284). Patients with high CD36 expression had significantly lower overall survival (OS) and recurrence-free survival (RFS) rates than patients with low expression; thus, CD36 was an independent prognostic factor for OS and RFS. In subgroup analyses, CD36 was an independent risk factor for OS and RFS in 59 patients treated with gemcitabine adjuvant chemotherapy. CD36 expression was upregulated in PDAC-GR cell lines compared with the PDAC parent cell line. Transduction with siRNA downregulated CD36, which reduced PDAC cell resistance to gemcitabine and inhibited anti-apoptosis proteins.

CONCLUSION

CD36 expression influenced gemcitabine resistance by regulating anti-apoptosis proteins. High CD36 expression was a significant, unfavorable prognostic factor in PDAC. Anti-CD36 treatment might serve as an optional treatment for lowering resistance to gemcitabine.

Interferon-α Combined With Herbal Compound "Songyou Yin" Effectively Inhibits the Increased Invasiveness and Metastasis by Insufficient Radiofrequency Ablation of Hepatocellular Carcinoma in an Animal Model

Objective: We had previously proved that insufficient radiofrequency ablation (RFA) could enhance invasiveness and metastasis of hepatocellular carcinoma (HCC) through epithelial-mesenchymal transition (EMT), which is mediated by activating β-catenin signaling. Thus, the aim of the present study was to demonstrate whether the combined treatment of interferon-α (IFN-α) and “Songyou Yin” (SYY) minimizes the pro-metastatic effects of insufficient RFA, as well as to explore its underlying mechanism. Methods: Insufficient RFA was performed in an orthotopic nude mice model of HCCLM3 with high metastatic potential. The effects of IFN-α, SYY, and combined IFN-α and SYY were observed in the animal model. Tumor sizes, lung metastasis, and survival time were assessed. Immunochemistry staining, real-time polymerase chain reaction, and Western blot were used to examine gene expression related to metastasis and angiogenesis in residual cancer after insufficient RFA. Results: For up to 8 weeks of treatment, the combined therapy significantly decreased the residual cancer sizes, minimized the lung metastasis rate, and prolonged the survival time of nude mice, which might be due to suppression of the EMT via β-catenin signal blockade, in addition to attenuating angiogenesis in residual cancer after insufficient RFA. Conclusion: IFN-α combined with SYY significantly weakened the enhanced metastatic potential of residual cancer after insufficient RFA by attenuating EMT, which is mediated through inhibiting activation of β-catenin. In addition, decreasing angiogenesis of residual cancer might also play a certain role.

Multicenter, randomized, controlled trial of S-1 monotherapy versus S-1 and interferon-α combination therapy for hepatocellular carcinoma with extrahepatic metastases

AIM

No effective therapies for extrahepatic metastases from hepatocellular carcinoma (HCC) have yet been identified. Previous studies suggested a potentially promising antitumor effect of combination therapy of S-1, a novel oral dihydropyrimidine dehydrogenase inhibitor, and interferon (IFN)-α. The present study aimed to investigate the clinical efficacy of single agent S-1 and S-1/IFN-α for HCC patients with extrahepatic metastases in a randomized, open-label, multicenter trial.

METHODS

A total of 103 patients with HCC with extrahepatic metastases were randomly assigned to the S-1/IFN-α group, receiving the combination of S-1 and IFN-α, or the S-1 group, receiving the single agent of S-1. Clinical efficacy and adverse events were compared between the two groups.

RESULTS

A total of 49 patients in the S-1/IFN-α group and 51 patients in the S-1 group were included in the efficacy analysis. The response rate was 22.4% (11/49) in the S-1/IFN-α group and 13.7% (7/51) in the S-1 group; there was no significant difference. Overall and progression-free survival in the two groups were also not significantly different (1-year overall survival 50.8% vs. 72.4%, median progression-free survival 127 days vs. 157 days). The incidence of grade ≥3 adverse events in the S-1/IFN-α group was 62.7% (32/51), which tended to be higher than in the S-1 group (43.1% [22/51]).

CONCLUSIONS

Oncological outcomes in both treatment groups were favorable compared with previous reports, though there was no significant beneficial effect of adding IFN-α to S-1 for the treatment of HCC patients with extrahepatic metastases.

A miR-29b Byproduct Sequence Exhibits Potent Tumor-Suppressive Activities via Inhibition of NF-κB Signaling in KRAS-Mutant Colon Cancer Cells

We previously demonstrated that miR-29b-3p is a hopeful miRNA-based therapy against colorectal cancer. In this study, we aimed to clarify a value of miR-29b-1-5p as a next-generation treatment, especially for KRAS-mutant colorectal cancer. RT-PCR assay showed that the expression of miR-29b-3p was high, and its partner strand, miR-29b-1-5p, level was only negligible in clinical colorectal cancer samples. Mimic-miR-29b-1-5p significantly inhibited proliferation of KRAS-mutant colorectal cancer cell lines DLD1 and SW480 and KRAS wild-type HT29 cells. Proliferative activity was further examined by either miR-29b-1-5p strand or its opposite complementary sequence because miR-29b-1-5p is a passenger miRNA and may have no physiologic function. We found that completely opposite complementary strand to miR-29b-1-5p, but not miR-29b-1-5p, possessed a potent antitumor effect and named this byproduct miRNA sequence "MIRTX." MIRTX directly targeted the 3'-UTR of CXCR2 and PIK3R1 mRNA and suppressed the NF-κB signaling pathway in KRAS-mutated colorectal cancer cells. MIRTX induced apoptosis in DLD1 with downregulation of antiapoptotic BCL2, BCL-xL, and MCL1 and upregulation of cleaved caspase-3 and cleaved PARP. In mouse xenograft models, systemic administration of MIRTX using a super carbonate apatite as a delivery vehicle significantly inhibited tumor growth of DLD1 and HT29 cells without any particular toxicities. In conclusion, these findings indicate that inhibition of NF-κB signaling by this novel miRNA-based therapeutic could be a promising treatment against refractory KRAS-mutant colorectal cancer and KRAS wild-type colorectal cancer. Mol Cancer Ther; 17(5); 977-87. ©2018 AACR.

Regulation of transforming growth factor is involved in the efficacy of combined 5-fluorouracil and interferon alpha-2b therapy of advanced hepatocellular carcinoma

Transforming growth factor-beta (TGF-β) is critical in cancer cell invasion and metastasis. The effects of a treatment that targets TGF-β using the combination of interferon alpha (IFNα)-2b and 5-fluorouracil (5-FU) are unknown. Here, we show that the serum levels of TGF-β1 prior to the therapy correlate with increased maximum tumor diameter, which is significantly (p < 0.01) decreased after the combination therapy. 5-FU increased both the expression and secretion levels of TGF-β1 in hepatoma cells, but not in normal hepatocytes. The combination of 5-FU and IFNα-2b synergistically affected cell death. However, a TGF-β1 specific inhibitor did not affect the anti-tumor activity of 5-FU. 5-FU inhibited the phosphorylation of SMAD2 and reduced the total protein levels of SMAD2, SMAD4, and pINK4b. Conversely, 5-FU stimulated the phosphorylation of extracellular signal-regulated kinase (ERK)1/2. Accordingly, the protein levels of E-cadherin and claudin-1 were reduced in 5-FU-treated cells. The combination of 5-FU and IFNα-2b, and the inhibition of ERK1/2 by a specific inhibitor neutralized the effects of 5-FU on TGF-β-related signaling molecules and restored their protein levels to those observed in the control. Interestingly, the phosphorylated protein levels of SMAD2 and the total protein levels of E-cadherin and p15INK4b were increased in 5-FU-stimulated HuH-7 cells, but not in Hep G2 cells. Our data suggest that the higher efficacy of the 5-FU and IFNα-2b combination therapy was associated with the regulation of TGF-β expression, secretion, and the signals mediated by it.

Therapeutic effect of targeted Fas-expressing adenoviruses method combining γδ T cells in a mouse model of human ovarian carcinoma

The present study aimed to investigate the therapeutic effect and safety of targeted use of Fas-expressing adenoviruses combined with γδ T cell-mediated killing to treat human ovarian cancer xenografts in BALB/c mice. Shuttle plasmids containing control elements of human telomerase reverse transcriptase promoter and two-step transcriptional amplification system were constructed and packaged into adenovirus-5 vectors to generate expression of an exogenous Fas gene. A mouse xenograft model of human ovarian carcinoma was constructed. A total of 35 BALB/c mice were randomly divided into five groups, which were injected with PBS, γδ T cells, Fas-expressing adenoviruses, taxol, or Fas-expressing adenovirus and γδ T cells. The weight and volume of tumors in mice in each group was monitored. Tissue sections of the various tissues of mice in the Fas-expressing adenovirus and γδ T cells group was compared with those in the PBS group to evaluate the safety of Fas-expressing adenovirus and γδ T cells in the treatment of human ovarian cancer xenograft tumors. The results of the present study indicated that mice in all treatment groups were alive at the end of the treatment course. Tumor weight and volume was the highest in the PBS group, followed successively by the adenovirus group, the γδ T cell group, the adenovirus and γδ T cell group, and the taxol group. The weight and volume inhibition rate in adenovirus and γδ T cell group were significantly higher compared with in the PBS group (P<0.05). Pathological observation of tissue samples revealed that none of vital organs in the adenovirus and γδ T cell group developed any evident morphological changes during treatment, when compared with healthy controls. In conclusion, the combined therapy with Fas-expressing adenoviruses and γδ T cells is efficient and safe for the treatment of mouse human ovarian carcinoma xenografts.

Effects of harmaline on cell growth of human liver cancer through the p53/p21 and Fas/FasL signaling pathways

The effects of harmaline on the viability and apoptosis of human liver carcinoma were investigated in vitro. HepG2 cells were treated with harmaline (0-10 µM), and the proliferation and apoptosis of HepG2 cells were investigated using an MTT assay and flow cytometry, respectively. The protein expression of cellular tumor antigen p53 (p53), cyclin-dependent kinase inhibitor 1 (p21), tumor necrosis factor receptor superfamily member 6 (Fas), Fas ligand (FasL) and caspase-8 was subsequently measured using western blotting. In addition, an ELISA was used to analyze caspase-8/3 activity. Harmaline significantly increased p53, p21, Fas and FasL protein expression in HepG2 cells. Additionally, treatment with harmaline significantly increased the expression of caspase-8 and caspase-8/3 activity. The results from the present study suggest that harmaline suppresses the viability, but induces the apoptosis, of human liver carcinoma cells through upregulation of the p53/p21 and Fas/FasL signaling pathways.

Viral hepatitis and hepatocellular carcinoma: etiology and management

Chronic hepatitis B virus (HBV) and chronic hepatitis C virus (HCV) are associated with hepatic fibrosis and development of hepatocellular carcinoma (HCC). There are differences and variation with the incidence of HCC worldwide. Additionally, HCC develops via different pathways with these viral hepatitides. This review outlines the various mechanisms and pathophysiology that contributes to this process. There will also be a review on the recommended screening for HCC. Treatment considerations, which are different for these viruses, will be outlined in this review.

Role of p63 and p73 isoforms on the cell death in patients with hepatocellular carcinoma submitted to orthotopic liver transplantation

Background & Aims

Patients with hepatocellular carcinoma (HCC) submitted to orthotopic liver transplantation (OLT) have a variable 5-year survival rate limited mostly by tumor recurrence. The etiology, age, sex, alcohol, Child-Pugh, and the immunesuppressor have been associated with tumour recurrence. The expression of ΔNp73 is related to the reduced survival of patients with HCC. The study evaluated the expression of p63 and p73 isoforms and cell death receptors, and their relation to tumour recurrence and survival. The results were in vitro validated in HCC cell lines.

Methods

HCC sections from patients submitted to OLT were used. The in vitro study was done in differentiated hepatitis B virus (HBV)-expressing Hep3B and control HepG2 cells. The expression of cell death receptors and cFLIP_S/L, caspase-8 and -3 activities, and cell proliferation were determined in control and p63 and p73 overexpressing HCC cells.

Results

The reduced tumor expression of cell death receptors and TAp63 and TAp73, and increased ΔNp63 and ΔNp73 expression were associated with tumor recurrence and reduced survival. The in vitro study demonstrated that HBV-expressing Hep3B vs HepG2 cells showed reduced expression of p63 and p73, cell death receptors and caspase activation, and increased cFLIP_L/cFLIP_S ratio. The overexpression of TAp63 and TAp73 exerted a more potent pro-apoptotic and anti-proliferative effects in Hep3B than HepG2-transfected cells which was related to cFLIP_L upregulation.

Conclusions

The reduction of TAp63 and TAp73 isoforms, rather than alteration of ΔN isoform expression, exerted a significant functional repercussion on cell death and proliferation in HBV-expressing HepB cells.

MicroRNA-155 Controls Exosome Synthesis and Promotes Gemcitabine Resistance in Pancreatic Ductal Adenocarcinoma

The cancer drug gemcitabine (GEM) is a key drug for treating pancreatic ductal adenocarcinoma (PDAC), but PDAC cells develop chemoresistance after long-term administration. Since the tolerance was immediately spread to every PDAC tissue in a patient, it is assumed that some certain efficient mechanisms underlay in the development of chemoresistance. Changes in the levels of particular microRNAs or alterations in intercellular communication play a dominant role in chemoresistance development, and recent data also suggest that exosomes play an important role in this process. In this study, we revealed that the loop conferred chemoresistance in PDAC cells. The loop was as follows; 1, The long-term exposure of GEM increased miR-155 expression in PDAC cells. 2, The increase of miR-155 induced two different functions; exosome secretion and chemoresistance ability via facilitating the anti-apoptotic activity. 3, Exosome deliver the miR-155 into the other PDAC cells and induce the following function. The target therapy to miR-155 or the exosome secretion effectively attenuated the chemoresistance, and these results were validated with both clinical samples and in vivo experiments. This mechanism represents a novel therapeutic target in GEM treatment to PDAC.

Early growth response 3 inhibits growth of hepatocellular carcinoma cells via upregulation of Fas ligand

Hepatocellular carcinoma (HCC) is a prevalent malignancy with aggressive biological behavior and poor prognosis. Early growth response 3 (EGR3) is a zinc finger transcription factor, and has been studied primarily in the context of neurodevelopment, autoimmunity, inflammation and angiogenesis. Accumulating evidence indicates that EGR3 is a novel suppressor gene of tumor initiation and progression in certain cancer events, but little work has been carried out in exploring the relationship between EGR3 and HCC growth. The purpose of this study was to investigate the possible effects of EGR3 on cell proliferation and apoptosis in HCC, and determine the underlying mechanisms. Here, we observed that EGR3 expression was frequently downregulated in HCC tissues and cell lines. Ectopic expression of EGR3 contributed to cell proliferation inhibition and apoptosis induction in HCC cells in vitro. Furthermore, the expression of Fas ligand (FasL) was significantly enhanced following upregulation of EGR3 in HCC cells, accompanied by an obvious increase of pro-apoptotic Bak and cell cycle inhibitor p21 expression. Based on nude mouse models, we demonstrated that ectopic expression of EGR3 markedly restricted tumor growth, and the expression of FasL was significantly increased in the xenograft tumor tissues which exhibited high EGR3 expression. We further established a co-transfection in HCC cells with EGR3 overexpression plasmid and FasL siRNA. We found that silencing of FasL gene impeded the anti-proliferative and pro-apoptotic effects, as well as the increase of Bak and p21 expression, suggesting an essential role of FasL in EGR3-mediated growth suppression in HCC cells. Collectively, in conclusion, EGR3 contributes to cell growth inhibition via upregulation of FasL in HCC.

Balance between IL-3 and type Iinterferons and their interrelationship with FasL dictates lifespan and effector functions of human basophils

BACKGROUND

In contrast to eosinophils and neutrophils, the regulation of the lifespan of human basophils is poorly defined, with the exception of the potent anti-apoptotic effect of IL-3 that also promotes pro-inflammatory effector functions and phenotypic changes. Type I IFNs (IFN-α, IFN-β), which are well known for their anti-viral activities, have the capacity to inhibit allergic inflammation.

OBJECTIVE

To elucidate whether type I IFNs have the potential to abrogate the lifespan and/or effector functions of human basophils.

METHODS

We cultured human basophils, and for comparison, eosinophils and neutrophils, with IL-3, interferons, FasL and TRAIL, alone or in combination, and studied cell survival, effector functions and signalling pathways involved.

RESULTS

Despite an identical pattern of early signalling in basophils, eosinophils and neutrophils in response to different types of interferons, only basophils displayed enhanced apoptosis after type I IFN treatment. IFN-γ prolonged survival of eosinophils but did not affect the lifespan of basophils. IFN-α-mediated apoptosis required STAT1-STAT2 heterodimers and the contribution of constitutive p38 MAPK activity. Whereas the death ligands FasL and TRAIL-induced apoptosis in basophils per se, IFN-α-mediated apoptosis did neither involve autocrine TRAIL signalling nor did it sensitize basophils to FasL-induced apoptosis. However, IFN-α and FasL displayed an additive effect in killing basophils. Interestingly, IL-3, which protected basophils from IFN-α-, TRAIL- or FasL-mediated apoptosis, did not completely block the additive effect of combined IFN-α and FasL treatment. Moreover, we demonstrate that IFN-α suppressed IL-3-induced release of IL-8 and IL-13. In contrast to IFN-α-mediated apoptosis, these inhibitory effects of IFN-α were not dependent on p38 MAPK signalling.

CONCLUSIONS AND CLINICAL RELEVANCE

Our study defines the unique and granulocyte-type-specific inhibitory and pro-apoptotic function of type I IFNs and their cooperation with death ligands in human blood basophils, which may be relevant for the anti-allergic properties of type I IFNs.

Quercetin Confers Tumoricidal Activity Through Multipathway Mechanisms in A N-Methylnitrosourea Rat Model of Colon Cancer

Objective: This research was conducted to explore mechanisms behind the potency of quercetin in inhibiting colon cancer induced in an experimental model. Materials and Methods: Forty adult male rats of Wistar strain were distributed into 4 groups; a negative control group, a colon cancer bearing group, a quercetin-treated group and a 5-fluorouracil (5-FU)-treated group. Serum TAG72 and GAL3 levels were quantified by ELISA. Colonic Wnt5a and Axin-1 gene expression was estimated by PCR. In addition, colonic tissues were subjected to immunohistochemical examination of Bax expression and histological investigation of histopathological alterations. Results: Quercetin elicited significant reduction in serum TAG72 and GAL3 levels, in addition to significant suppression of colonic Wnt5a gene expression and amplification of colonic Axin-1 gene expression. Also, it caused moderate positive reaction for Bax in mucosal epithelium. Conclusion: The present research provides experimental evidence about the activity of quercetin in the colon cancer of rats. Inhibitory effects on cancer development might be ascribable to regulatory action on Wnt signaling and induction of apoptosis.

Mechanisms of Drug Resistance in Veterinary Oncology- A Review with an Emphasis on Canine Lymphoma

Drug resistance (DR) is the major limiting factor in the successful treatment of systemic neoplasia with cytotoxic chemotherapy. DR can be either intrinsic or acquired, and although the development and clinical implications are different, the underlying mechanisms are likely to be similar. Most causes for DR are pharmacodynamic in nature, result from adaptations within the tumor cell and include reduced drug uptake, increased drug efflux, changes in drug metabolism or drug target, increased capacity to repair drug-induced DNA damage or increased resistance to apoptosis. The role of active drug efflux transporters, and those of the ABC-transporter family in particular, have been studied extensively in human oncology and to a lesser extent in veterinary medicine. Methods reported to assess ABC-transporter status include detection of the actual protein (Western blot, immunohistochemistry), mRNA or ABC-transporter function. The three major ABC-transporters associated with DR in human oncology are ABCB1 or P-gp, ABCC1 or MRP1, and ABCG2 or BCRP, and have been demonstrated in canine cell lines, healthy dogs and dogs with cancer. Although this supports a causative role for these ABC-transporters in DR cytotoxic agents in the dog, the relative contribution to the clinical phenotype of DR in canine cancer remains an area of debate and requires further prospective studies.

Antitumoral gene-based strategy involving nitric oxide synthase type III overexpression in hepatocellular carcinoma

Hepatocellular carcinoma develops in cirrhotic liver. The nitric oxide (NO) synthase type III (NOS-3) overexpression induces cell death in hepatoblastoma cells. The study developed gene therapy designed to specifically overexpress NOS-3 in cultured hepatoma cells, and in tumors derived from orthotopically implanted tumor cells in fibrotic livers. Liver fibrosis was induced by CCl4 administration in mice. The first-generation adenoviruses were designed to overexpress NOS-3 or green fluorescent protein, and luciferase complementary DNA under the regulation of murine alpha-fetoprotein (AFP) and Rous Sarcoma Virus (RSV) promoters, respectively. Both adenovirus and Hepa 1-6 cells were used for in vitro and in vivo experiments. Adenoviruses were administered through the tail vein 2 weeks after orthotopic tumor cell implantation. AFP-NOS-3/RSV-luciferase increased oxidative-related DNA damage, p53, CD95/CD95L expression and caspase-8, -9 and -3 activities in cultured Hepa 1-6 cells. The increased expression of CD95/CD95L and caspase-8 activity was abolished by Nω-nitro-l-arginine methyl ester hydrochloride, p53 and CD95 small interfering RNA. AFP-NOS-3/RSV-luciferase adenovirus increased cell death markers, and reduced cell proliferation of established tumors in fibrotic livers. The increase of oxidative/nitrosative stress induced by NOS-3 overexpression induced DNA damage, p53, CD95/CD95L expression and cell death in hepatocellular carcinoma cells. The effectiveness of the gene therapy has been demonstrated in vitro and in vivo.

Hepatitis B virus core protein inhibits Fas-mediated apoptosis of hepatoma cells via regulation of mFas/FasL and sFas expression

Hepatitis B virus core protein (HBc) has been implicated in hepatocarcinogenesis through several mechanisms. Resistance of hepatitis B virus (HBV)-infected hepatocytes to apoptosis is considered one of the major contributors to the progression of chronic hepatitis to cirrhosis and ultimately to hepatocellular carcinoma. The Fas receptor/ligand (Fas/FasL) system plays a prominent role in hepatocyte death during HBV infection. Here we report that HBc mediates resistance of hepatoma cells to agonistic anti-Fas antibody (CH11)-induced apoptosis. When HBc was introduced into human hepatoma cells, the cells became resistant to CH11 cytotoxicity in a p53-dependent manner. HBc significantly down-regulated the expression of p53, total Fas, and membrane-bound Fas at the mRNA and protein levels and reduced FasL mRNA expression. In contrast, HBc up-regulated the expression of soluble forms of Fas by increasing Fas alternative mRNA splicing. Mechanistically, HBc-mediated Fas alternative mRNA splicing was associated with up-regulation of polypyrimidine tract-binding protein 1 and down-regulation of Fas-activated serine/threonine kinase. These results indicated that HBc may prevent hepatocytes from Fas-induced apoptosis by the dual effects of reducing the expression of the proapoptotic form of Fas and enhancing the expression of the antiapoptotic form of the receptor, which may contribute to the survival and persistence of infected hepatocytes during chronic infection.

Interferon-alpha and interferon-gamma modulate Fas-mediated apoptosis in mitomycin-C-resistant human Tenon's fibroblasts

BACKGROUND

The aim of the study was to investigate, using a native mitomycin-C-resistant human Tenon's fibroblast cell line, the possibility that interferon-alpha and gamma could be used with Fas agonists as an alternative anti-fibrotic strategy to mitomycin-C in trabeculectomy.

METHODS

A clinically resistant and in vitro verified mitomycin-C-resistant human Tenon's fibroblast cell line was pretreated with interferon-alpha and interferon-gamma for 48 h before stimulation with an agonistic Fas antibody (CH11) for 2 days to induce cell death. Cell death assays were undertaken. Changes in apoptosis-related proteins were determined by flow cytometry and Western blot.

RESULTS

Pretreatment with interferon-alpha or interferon-gamma for 48 h increased Fas, Fas-associated protein with death domain and caspase-8 expression. Protein expression was further increased by combined exposure to interferon-alpha and gamma. Pretreatment with cytokines had no effect on Fas-L and Bcl-2. Interferon-alpha alone did not change the rate of induced cell death. A combination of interferon-alpha and gamma synergistically increased the sensitivity of mitomycin-C-resistant human Tenon's fibroblast cell line to induced cell death. An antagonistic anti-Fas antibody (ZB4) completely blocked induced cell death. Broad caspase inhibitors specific for caspases-8 and -3 reduced induced deaths in interferon pretreated mitomycin-C-resistant human Tenon's fibroblast cell line in a dose-dependent manner.

CONCLUSIONS

Interferon-alpha and interferon-gamma render mitomycin-C-resistant human Tenon's fibroblast cell line sensitive to Fas-mediated apoptosis. The mechanism involves increased death-inducing signalling complex formation by upregulation of Fas, Fas-associated protein with death domain and caspase-8 expression.

Calcium signaling in the liver

Intracellular free Ca(2+) ([Ca(2+)]i) is a highly versatile second messenger that regulates a wide range of functions in every type of cell and tissue. To achieve this versatility, the Ca(2+) signaling system operates in a variety of ways to regulate cellular processes that function over a wide dynamic range. This is particularly well exemplified for Ca(2+) signals in the liver, which modulate diverse and specialized functions such as bile secretion, glucose metabolism, cell proliferation, and apoptosis. These Ca(2+) signals are organized to control distinct cellular processes through tight spatial and temporal coordination of [Ca(2+)]i signals, both within and between cells. This article will review the machinery responsible for the formation of Ca(2+) signals in the liver, the types of subcellular, cellular, and intercellular signals that occur, the physiological role of Ca(2+) signaling in the liver, and the role of Ca(2+) signaling in liver disease.

Bozepinib, a novel small antitumor agent, induces PKR-mediated apoptosis and synergizes with IFNα triggering apoptosis, autophagy and senescence

Bozepinib [(RS)-2,6-dichloro-9-[1-(p-nitrobenzenesulfonyl)-1,2,3,5-tetrahydro-4,1-benzoxazepin-3-yl]-9H-purine] is a potent antitumor compound that is able to induce apoptosis in breast cancer cells. In the present study, we show that bozepinib also has antitumor activity in colon cancer cells, showing 50% inhibitory concentration (IC₅₀) values lower than those described for breast cancer cells and suggesting great potential of this synthetic drug in the treatment of cancer. We identified that the double-stranded RNA-dependent protein kinase (PKR) is a target of bozepinib, being upregulated and activated by the drug. However, p53 was not affected by bozepinib, and was not necessary for induction of apoptosis in either breast or colon cancer cells. In addition, the efficacy of bozepinib was improved when combined with the interferon-alpha (IFNα) cytokine, which enhanced bozepinib-induced apoptosis with involvement of protein kinase PKR. Moreover, we report here, for the first time, that in combined therapy, IFNα induces a clear process of autophagosome formation, and prior treatment with chloroquine, an autophagy inhibitor, is able to significantly reduce IFNα/bozepinib-induced cell death. Finally, we observed that a minor population of caspase 3-deficient MCF-7 cells persisted during long-term treatment with lower doses of bozepinib and the bozepinib/IFNα combination. Curiously, this population showed β-galactosidase activity and a percentage of cells arrested in S phase, that was more evident in cells treated with the bozepinib/IFNα combination than in cells treated with bozepinib or IFNα alone. Considering the resistance of some cancer cells to conventional chemotherapy, combinations enhancing the diversity of the cell death outcome might succeed in delivering more effective and less toxic chemotherapy.

Silencing of Pokemon enhances caspase-dependent apoptosis via fas- and mitochondria-mediated pathways in hepatocellular carcinoma cells

The role of Pokemon (POK erythroid myeloid ontogenic actor), a recently identified POK transcription factor with proto-oncogenic activity, in hepatocellular carcinogenesis has only been assessed by a few studies. Our previous study revealed that Pokemon is overexpressed in hepatocellular carcinomas (HCC) and promotes HCC cell proliferation and migration via an AKT- and ERK- dependent manner. In the present study, we used the TUNEL assay and FACS analysis to demonstrate that oxaliplatin induced apoptosis was significantly increased in cells with silenced Pokemon. Western blots showed that p53 expression and phosphorylation were significantly increased in Pokemon defective cells, thereby initiating the mitochondria-mediated and death receptor-mediated apoptotic pathways. In the mitochondria-mediated pathway, expression of pro-apoptotic Bcl-2 family members (including Bad, Bid, Bim and Puma) as well as AIF was increased and decreasing the mitochondrial membrane potential resulted in cytochrome C released from mitochondrial in HepG2 si-Pokemon cells. In addition, upon oxaliplatin treatment of Pokemon-silenced cells, the FAS receptor, FADD and their downstream targets caspase-10 and caspase-8 were activated, causing increased release of caspase-8 active fragments p18 and p10. Increased activated caspase-8-mediated cleavage and activation of downstream effector caspases such as caspase-9 and caspase-3 was observed in HepG2 si-Pokemon cells as compared to control. Therefore, Pokemon might serve as an important mediator of crosstalk between intrinsic and extrinsic apoptotic pathways in HCC cells. Moreover, our findings suggest that Pokemon could be an attractive therapeutic target gene for human cancer therapy.

Silencing the EZH2 gene by RNA interference reverses the drug resistance of human hepatic multidrug-resistant cancer cells to 5-Fu

AIMS

The EZH2 gene, which is expressed in various solid tumours, including liver cancer, can regulate gene transcription and promote the generation and progression of tumours. Our aim was to investigate the relationship between EZH2 and multidrug-resistance of human hepatic cancer cells using RNA interference.

MAIN METHODS

We detected the expression of EZH2 in the human hepatic multidrug-resistant cancer cell line Bel/Fu by RT-PCR and western blot; then knocked EZH2 gene by RNA interference to investigate the proliferation, the cell cycle and cell apoptosis by MTT and flow cytometry; finally we checked the alteration of MDR1 methylation and MDR1 expression after EZH2 silencing by MS-PCR, RT-PCR and western blot.

KEY FINDINGS

EZH2 is highly expressed in Bel/Fu cells. After EZH2-depleted Bel/Fu cells were treated with 5-Fu, the cell proliferation was inhibited, the cell cycle arrested at G1, which may be associated with the alteration of G1/S checkpoint regulators, meanwhile the apoptotic rate of the cells increased. Furthermore, the expression of MDR1 decreased and the corresponding methylation levels of MDR1 were significantly increased in EZH2-depleted Bel/Fu cells.

SIGNIFICANCE

We demonstrate the relationship between EZH2 and multidrug-resistance in hepatic cancer for the first time. EZH2 may become a new target for gene therapy to reverse multidrug-resistance in hepatic cancer.

PTK787/ZK222584 combined with interferon alpha and 5-fluorouracil synergistically inhibits VEGF signaling pathway in hepatocellular carcinoma

BACKGROUND

The prognosis of patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus remains poor. We previously reported the beneficial effects of interferon alpha (IFN) and 5-fluorouracil (5-FU) combination therapy for these patients. We showed that the mechanism of therapy was regulation of vascular endothelial growth factor (VEGF). Here, we combined IFN/5-FU therapy with the VEGF receptor-selective inhibitor PTK787/ZK222584 (PTK/ZK) and examined the antitumor effects and the mechanism of action.

METHODS

We studied two HCC cell lines, PLC/PRF/5 and HuH7, and a human umbilical vein endothelial cell line, HUVEC. We studied the effects of IFN/5-FU with or without PTK/ZK in growth inhibition assays, immunohistochemistry, Western blot analysis, and immunocytochemistry.

RESULTS

In a HuH7 xenograft model, the combination of PTK/ZK and IFN/5-FU significantly inhibited proliferation, induced apoptosis, decreased microvessel density, reduced the number of tumor cells that expressed VEGF receptor 2 (VEGFR-2), and repressed the phosphorylation of Akt in vivo. In HCC cells and HUVECs in vitro, IFN/5-FU plus PTK/ZK repressed the expression of VEGFR-2 and repressed the phosphorylation of VEGFR, Akt, Erk, and p38MAPK.

CONCLUSIONS

VEGF signaling inhibition enhanced the antitumor effects of IFN/5-FU therapy on HCC cells and endothelial cells via Erk, Akt, and p38MAPK pathways.

Identification of the genes chemosensitizing hepatocellular carcinoma cells to interferon-α/5-fluorouracil and their clinical significance

The incidence of advanced hepatocellular carcinoma (HCC) is increasing worldwide, and its prognosis is extremely poor. Interferon-alpha (IFN-α)/5-fluorouracil (5-FU) therapy is reportedly effective in some HCC patients. In the present study, to improve HCC prognosis, we identified the genes that are sensitizing to these agents. The screening strategy was dependent on the concentration of ribozymes that rendered HepG2 cells resistant to 5-FU by the repeated transfection of ribozymes into the cells. After 10 cycles of transfection, which was initiated by 5,902,875 sequences of a ribozyme library, three genes including protein kinase, adenosine monophosphate (AMP)-activated, gamma 2 non-catalytic subunit (PRKAG2); transforming growth factor-beta receptor II (TGFBR2); and exostosin 1 (EXT1) were identified as 5-FU-sensitizing genes. Adenovirus-mediated transfer of TGFBR2 and EXT1 enhanced IFN-α/5-FU-induced cytotoxicity as well as 5-FU, although the overexpression of these genes in the absence of IFN-α/5-FU did not induce cell death. This effect was also observed in a tumor xenograft model. The mechanisms of TGFBR2 and EXT1 include activation of the TGF-β signal and induction of endoplasmic reticulum stress, resulting in apoptosis. In HCC patients treated with IFN-α/5-FU therapy, the PRKAG2 mRNA level in HCC tissues was positively correlated with survival period, suggesting that PRKAG2 enhances the effect of IFN-α/5-FU and serves as a prognostic marker for IFN-α/5-FU therapy. In conclusion, we identified three genes that chemosensitize the effects of 5-FU and IFN-α/5-FU on HCC cells and demonstrated that PRKAG2 mRNA can serve as a prognostic marker for IFN-α/5-FU therapy.

Targeting hepatoma using nitric oxide donor strategies

AIMS

The study evaluated the role of increased intracellular nitric oxide (NO) concentration using NO donors or stably NO synthase-3 (NOS-3) overexpression during CD95-dependent cell death in hepatoma cells. The expression of cell death receptors and caspase activation, RhoA kinase activity, NOS-3 expression/activity, oxidative/nitrosative stress, and p53 expression were analyzed. The antitumoral activity of NO was also evaluated in the subcutaneous implantation of NOS-3-overexpressing hepatoma cells, as well NO donor injection into wild-type hepatoma-derived tumors implanted in xenograft mouse models.

RESULTS

NO donor increased CD95 expression and activation of caspase-8 and 3 in HepG2, Huh7, and Hep3B cells. NOS-3 overexpression increased oxidative/nitrosative stress, p53 and CD95 expression, cellular Fas-associated death domain (FADD)-like IL-1beta converting enzyme (FLICE) inhibitory protein long (cFLIP(L)) and its short isoform (cFLIP(S)) shift, and cell death in HepG2 (4TO-NOS) cells. The inhibition of RhoA kinase and p53 knockdown using RNA interference reduced cell death in 4TO-NOS cells. The supplementation with hydrogen peroxide (H(2)O(2)) increased NOS-3 activity and cell death in 4TO-NOS cells. NOS-3 overexpression or NO donor injection into hepatoma-derived tumors reduced the size and increased p53 and cell death receptor expression in nude mice.

INNOVATION AND CONCLUSIONS

The increase of intracellular NO concentration promoted oxidative and nitrosative stress, Rho kinase activity, p53 and CD95 expression, and cell death in cultured hepatoma cells. NOS-3-overexpressed HepG2 cells or intratumoral NO donor administration reduced tumor cell growth and increased the expression of p53 and cell death receptors in tumors developed in a xenograft mouse model.

Combined IFN-α and 5-FU treatment as a postoperative adjuvant following surgery for hepatocellular carcinoma with portal venous tumor thrombus

The efficacy of combination therapy with subcutaneous interferon (IFN)-α and intra-arterial 5-fluorouracil (5-FU) as a postoperative adjuvant for resectable advanced hepatocellular carcinoma (HCC) invading the major branches of the portal vein (PVTT) was examined. The prognosis of HCC with PVTT (Vp3 or 4) is extremely poor. Recently, we reported the possibility of combination therapy with IFN-α and intra-arterial 5-FU for intractable HCC with PVTT as a postoperative adjuvant and this is the second report. Patients with HCC with PVTT were included (n=50). Thirty consecutive patients with HCC and PVTT were treated with 3 cycles of a combination therapy consisting of arterial 5-FU infusion (300 mg/mm(3)/day, 5 days/week, for the initial 2 weeks) and IFN subcutaneous injection (5 MIU, 3 times/week, 4 weeks) as a postoperative adjuvant following hepatic resection; another 20 patients receiving no IFN/5-FU chemotherapy acted as controls. Results for the IFN/5-FU adjuvant treatment group were as follows: disease-free survival (n=9, 15-109 months), survival with recurrence (n=6, 30-92 months), cancer death (n=9, 14-60 months), death from other causes but no recurrence (n=5, 13-87 months) and death from other causes with recurrence (n=1, 22 months). The 1-year survival rate was 100% in patients treated with IFN/5-FU, and 30% in those without IFN/5-FU as historical controls (n=20). There was a significant difference in disease-free and overall survival rates between the two groups (P<0.0001). In conclusion, IFN/5-FU combination therapy may be a very promising postoperative adjuvant treatment for HCC with PVTT.

Systemic combination therapy of intravenous continuous 5-fluorouracil and subcutaneous pegylated interferon alfa-2a for advanced hepatocellular carcinoma

BACKGROUND

In Japan, sorafenib is now the first-line therapy for individuals with advanced hepatocellular carcinoma (HCC), but no other treatment is available for such patients. The aim of this study was to assess the efficacy and safety of combination therapy with systemic continuous intravenous infusion of 5-fluorouracil (5-FU) and subcutaneous peginterferon alfa-2a, which was used before sorafenib was introduced to Japan.

METHODS

Two hundred and twenty-three HCC patients, who were not amenable to curative surgery, percutaneous ablation, or transarterial chemoembolization (TACE), and for whom intraarterial chemotherapy was not indicated because of the presence of extrahepatic metastasis or stenosis of the common hepatic artery, received peginterferon alfa-2a (90 μg subcutaneously on days 1, 8, 15, and 22) and 5-FU (500 mg/day intravenously given continuously on days 1-5 and 8-12). We assessed their response to treatment and survival, and treatment safety.

RESULTS

The response rate was 9.4 % (including six patients with complete response) and the disease-control rate was 32.7 %. The median time to progression was 2.0 months. The overall median survival time was 6.5 months (Child-Pugh class A: 9.2 months vs. Child-Pugh class B: 2.8 months). In a multivariate analysis, Eastern Cooperative Oncology Group (ECOG) performance status >0, Child-Pugh class B, and the presence of macroscopic vascular invasion were independent predictors of poor prognosis. The major grade 3-4 adverse events were leucopenia (13.9 %) and thrombocytopenia (5.8 %). No treatment-related deaths occurred.

CONCLUSIONS

This combination therapy was well tolerated and showed promising efficacy. Further studies are needed to establish the usefulness of this treatment.

Antagonist effect of triptolide on AKT activation by truncated retinoid X receptor-alpha

Background

Retinoid X receptor-alpha (RXRα) is a key member of the nuclear receptor superfamily. We recently demonstrated that proteolytic cleavage of RXRα resulted in production of a truncated product, tRXRα, which promotes cancer cell survival by activating phosphatidylinositol-3-OH kinase (PI3K)/AKT pathway. However, how the tRXRα-mediated signaling pathway in cancer cells is regulated remains elusive.

Methodology/Principal Findings

We screened a natural product library for tRXRα targeting leads and identified that triptolide, an active component isolated from traditional Chinese herb Trypterygium wilfordii Hook F, could modulate tRXRα-mediated cancer cell survival pathway in vitro and in animals. Our results reveal that triptolide strongly induces cancer cell apoptosis dependent on intracellular tRXRα expression levels, demonstrating that tRXRα serves as an important intracellular target of triptolide. We show that triptolide selectively induces tRXRα degradation and inhibits tRXRα-dependent AKT activity without affecting the full-length RXRα. Interestingly, such effects of triptolide are due to its activation of p38. Although triptolide also activates Erk1/2 and MAPK pathways, the effects of triptolide on tRXRα degradation and AKT activity are only reversed by p38 siRNA and p38 inhibitor. In addition, the p38 inhibitor potently inhibits tRXRα interaction with p85α leading to AKT inactivation. Our results demonstrate an interesting novel signaling interplay between p38 and AKT through tRXRα mediation. We finally show that targeting tRXRα by triptolide strongly activates TNFα death signaling and enhances the anticancer activity of other chemotherapies

Conclusions/Significance

Our results identify triptolide as a new xenobiotic regulator of the tRXRα-dependent survival pathway and provide new insight into the mechanism by which triptolide acts to induce apoptosis of cancer cells. Triptolide represents one of the most promising therapeutic leads of natural products of traditional Chinese medicine with unfortunate side-effects. Our findings will offer new strategies to develop improved triptolide analogs for cancer therapy.

The novel NF-κB inhibitor DHMEQ synergizes with celecoxib to exert antitumor effects on human liver cancer cells by a ROS-dependent mechanism

In a previous work of ours dehydroxymethyl-epoxyquinomicin (DHMEQ), an inhibitor of NF-κB, was shown to induce apoptosis through Reactive Oxygen Species (ROS) production in hepatoma cells. The present study demonstrated that DHMEQ cooperates with Celecoxib (CLX) to decrease NF-κB DNA binding and to inhibit cell growth and proliferation more effectively than treatment with these single agents alone in the hepatoma cell lines HA22T/VGH and Huh-6. ROS production induced by the DHMEQ-CLX combination in turn generated the expression of genes involved in endoplasmic reticulum (ER) stress and silencing TRB3 mRNA significantly decreased DHMEQ-CLX-induced cell growth inhibition. Moreover, the DHMEQ-CLX combination was associated with induction of PARP cleavage and down-regulation of the anti-apoptotic proteins Bcl-2, Mcl-1 and survivin, as well as activated Akt. CD95 and CD95 ligand expression increased synergistically in the combination treatment, which was reversed in the presence of NAC. Knockdown of CD95 mRNA expression significantly decreased DHMEQ-CLX-induced cell growth inhibition in both cell lines. These data suggest that the DHMEQ-CLX combination kills hepatoma cells via ROS production, ER stress response and the activation of intrinsic and extrinsic apoptotic pathways.

The chemotherapeutic drug 5-fluorouracil promotes PKR-mediated apoptosis in a p53-independent manner in colon and breast cancer cells

The chemotherapeutic drug 5-FU is widely used in the treatment of a range of cancers, but resistance to the drug remains a major clinical problem. Since defects in the mediators of apoptosis may account for chemo-resistance, the identification of new targets involved in 5-FU-induced apoptosis is of main clinical interest. We have identified the ds-RNA-dependent protein kinase (PKR) as a key molecular target of 5-FU involved in apoptosis induction in human colon and breast cancer cell lines. PKR distribution and activation, apoptosis induction and cytotoxic effects were analyzed during 5-FU and 5-FU/IFNα treatment in several colon and breast cancer cell lines with different p53 status. PKR protein was activated by 5-FU treatment in a p53-independent manner, inducing phosphorylation of the protein synthesis translation initiation factor eIF-2α and cell death by apoptosis. Furthermore, PKR interference promoted a decreased response to 5-FU treatment and those cells were not affected by the synergistic antitumor activity of 5-FU/IFNα combination. These results, taken together, provide evidence that PKR is a key molecular target of 5-FU with potential relevance in the clinical use of this drug.

Long-term outcome of combined interferon-α and 5-fluorouracil treatment for advanced hepatocellular carcinoma with major portal vein thrombosis

BACKGROUND/AIM

We previously reported the beneficial effects of a combination therapy of interferon (IFN)-α/5-fluorouracil (FU) for advanced hepatocellular carcinoma (HCC) with tumor thrombi in the major portal branches. This report describes the results of longer follow-up and includes more than twice the number of patients relative to the previous report; it also evaluates the clinical predictor on the response to the combination therapy and long-term survival.

METHODS

The study subjects were 102 patients with advanced HCC and tumor thrombi in the major branches of the portal vein (Vp3 or 4). They were treated with at least 2 courses of IFN-α/5-FU.

RESULTS

No major treatment-related complications were noted. In the 102 patients, 40 (39.2%) showed objective response [11 (10.8%) showed complete response, 29 (28.4%) partial response], 8 (7.9%) showed no response and 54 (52.9%) showed progressive disease.

CONCLUSION

IFN-α/5-FU combination therapy is a promising modality for advanced HCC with tumor thrombi in the major portal branches.

IGFBP7 downregulation is associated with tumor progression and clinical outcome in hepatocellular carcinoma

Insulin-like growth factor-binding protein 7 (IGFBP7) functions in several cellular processes including proliferation, senescence and apoptosis. This study analyzed IGFBP7 function in hepatocellular carcinoma (HCC) cells by gene manipulation and investigated the prognostic significance of IGFBP7 expression in clinical HCC samples. In this study, we investigated changes in malignant potential such as cell growth and invasiveness in an HCC cell line, PLC/PRF/5, after transfection with shRNA against IGFBP7. The extent of apoptosis and cell cycle progression were examined after the transfection. The correlation between immunohistochemically determined IGFBP7 expression and long-term postoperative prognosis after curative resection was also investigated in clinical HCC specimens obtained from 104 patients. PLC/PRF/5 cells transfected with shRNA against IGFBP7 showed significantly more rapid growth and stronger invasiveness than control cells. Annexin V assays showed that the IGFBP7-depleted cells were significantly more resistant to apoptosis than the control cells, and showed decreased expression of cleaved caspase-3 and PARP. Cell cycle progression was more rapid in the IGFBP7-suppressed cells. In clinical HCC specimens, IGFBP7 expression was judged as positive in 67 patients (64.4%) and negative in the remaining 37 patients (35.6%). The IGFBP7 downregulation correlated significantly with poor postoperative prognosis, and IGFBP7 status was identified as an independent significant prognostic factor. Our results indicated that IGFBP7 expression correlated significantly with the malignant potential in HCC cells, suggesting that the expression could be a useful prognostic marker for HCC.

Combination of interferon-α and 5-fluorouracil induces apoptosis through mitochondrial pathway in hepatocellular carcinoma in vitro

Many clinical reports have proven that the combination therapy of interferon-alpha plus 5-fluorouracil is remarkably effective for advanced hepatocellular carcinoma (HCC). However, the mechanism of this therapy is not well understood. Here, we demonstrated that the combination therapy synergistically inhibited the growth of Fas-negative HCC cells, arrested cell-cycle progression and induced apoptosis. Moreover, the combination therapy significantly increased the protein expression of caspase-8, activated Bid and cytochrome c. Meanwhile, the expression of anti-apoptotic gene Bcl-xL was reduced and intracellular calcium elevated obviously during the early stage of treatment. Therefore, mitochondrial pathway was involved in the apoptosis of Fas-negative HCC cells induced by IFN-α/5-FU and Ca(2+) partially promoted the beneficial effect against HCC.

MicroRNA-21 induces resistance to the anti-tumour effect of interferon-α/5-fluorouracil in hepatocellular carcinoma cells

Background:

We reported recently the clinical efficiency of interferon (IFN)-α/5-fluorouracil (5-FU) combination therapy in advanced hepatocellular carcinoma (HCC). However, prediction of the response to the combination therapy remains unsatisfactory. The aim of this study was to investigate the anti-tumour effects of microRNA (miR)-21 on the sensitivity of HCC cells to IFN-α/5-FU and whether miR-21 can be used as a predictor of the response to such therapy in HCC.

Methods:

Changes in the sensitivity of HCC cells (PLC/PRF/5 and HepG2) to IFN-α/5-FU were examined after transfection with pre-miR-21 or anti-miR-21. The correlation between miR-21 expression level, evaluated by qRT–PCR, and response to the therapy was also investigated in clinical HCC specimens.

Results:

Hepatocellular carcinoma cells transfected with pre-miR-21 were significantly resistant to IFN-α/5-FU. Annexin V assay showed that the percentage of apoptotic cells was significantly lower in cells transfected with pre-miR-21 than control cells. Transfection of anti-miR-21 rendered HCC cells sensitive to IFN-α/5-FU, and such sensitivity was weakened by transfection of siRNAs of target molecules, PETN and PDCD4. miR-21 expression in clinical HCC specimens was significantly associated with the clinical response to the IFN-α/5-FU combination therapy and survival rate.

Conclusions:

The miR-21 in HCC cell lines and clinical HCC samples is a significant modulator of the anti-tumour effect of IFN-α and 5-FU. This suggests that miR-21 is a potentially suitable marker for the prediction of the clinical response to the IFN-α/5-FU combination therapy.

Tyrosine kinase inhibitor PTK/ZK enhances the antitumor effects of interferon-α/5-fluorouracil therapy for hepatocellular carcinoma cells

PURPOSE

There is no standardized treatment for hepatocellular carcinoma (HCC) with portal vein tumor thrombus. We previously reported the efficacy of interferon-alpha and 5-fluorouracil combination (IFN/5-FU) therapy for these patients and the potential mechanism via the regulation of vascular endothelial growth factor (VEGF). In this study, we showed the VEGF-related effects of IFN/5-FU therapy using VEGF-receptor (VEGFR) selective inhibitor, PTK787/ZK222584 (PTK/ZK), in HCC cells.

METHODS

Using two VEGF secreting and VEGFR expressing human HCC cell lines, PLC/PRF/5 and HuH7, we performed growth inhibitory assays in vitro and in vivo, apoptosis assay, cell cycle analysis, and Western blot analysis for the mechanism, with or without PTK/ZK in IFN/5-FU therapy.

RESULTS

The combination of PTK/ZK and IFN/5-FU significantly inhibited cell growth in vitro and tended to reduce tumor growth in vivo in a HuH7 xenograft model in nude mice-in both cases without affecting VEGF secretion. PTK/ZK enhanced the IFN/5-FU induced apoptosis, based on increased proteins levels of Bax and reduced Bcl-xL and Bcl-2. Cell cycle analysis showed different results between the HCC cell lines following the combination therapy, possibly due to differences in p21 protein.

CONCLUSIONS

VEGF signaling inhibition would support an antitumor effect of IFN/5-FU therapy against HCC cell lines via induction of apoptosis and cell cycle delay.

Oncolytic herpes simplex virus vectors and chemotherapy: are combinatorial strategies more effective for cancer?

Despite aggressive treatments, including chemotherapy and radiotherapy, cancers often recur owing to resistance to conventional therapies. Oncolytic viruses such as oncolytic herpes simplex virus (oHSV) represent an exciting biological approach to cancer therapy. A range of viral mutations has been engineered into HSV to engender oncolytic activity. While oHSV as a single agent has been tested in a number of cancer clinical trials, preclinical studies have demonstrated enhanced efficacy when it is combined with cytotoxic anticancer drugs. Among the strategies that will be discussed in this article are combinations with standard-of-care chemotherapeutics, expression of prodrug-activating enzymes to enhance chemotherapy and small-molecule inhibitors. The combination of oHSV and chemotherapy can achieve much more efficient cancer cell killing than either single agent alone, often through synergistic interactions. This can be clinically important not just for improving efficacy but also for permitting lower and less toxic chemotherapeutic doses. The viral mutations in an oHSV vector often determine the favorability of its interactions with chemotherapy, just as different cancer cells, due to genetic alterations, vary in their response to chemotherapy. As chemotherapeutics are often the standard of care, combining them with an investigational new drug, such as oHSV, is clinically easier than combining multiple novel agents. As has become clear for most cancer therapies, multimodal treatments are usually more effective. In this article, we will discuss the recent progress of these combinatorial strategies between virotherapy and chemotherapy and future directions.

Effects of pegylated interferon α2b on metastasis of hepatocellular carcinoma

OBJECTIVE

Interferon (IFN) has an anti-tumor activity in hepatocellular carcinoma (HCC) via anti-angiogenesis and induction of apoptosis. We have previously reported anti-metastatic effects of IFN combined chemotherapy on the outcome of HCC patients. The aim of this study was to investigate anti-metastatic effects of IFN.

METHODS

In vitro, pegylated interferon α2b (PEG-IFN-α2b) was administered to mouse MH134 cells (mouse HCC cell line, MH134), and anti-implantation effects were examined by evaluating the inhibition of cell invasion and cell proliferation. Expressions of vascular endothelial growth factor (VEGF) mRNA were also measured. In vivo, PEG-IFN-α2b was subcutaneously administered into MH134 cells and tumor growth was evaluated. In distant metastasis models, PEG-IFN-α2b was subcutaneously administered and MH134 cells were injected into the spleen. The number of liver metastases and microvessel densities (MVD) were counted.

RESULTS

In vitro, the proliferation of MH134 cells was significantly suppressed by PEG-IFN-α2b dose-dependently. MH134 cells added with PEG-IFN-α2b exhibited significantly lower levels of invasion potential. In vivo, tumor size in mice treated with PEG-IFN-α2b significantly suppressed compared with control mice (mean 0.5 versus 5.0 cm, in diameter, P < 0.05) and also decreased number of liver metastases (19.3 versus 6.0, P < 0.05). Moreover, PEG-IFN-α2b significantly suppressed angiogenesis compared with the control.

CONCLUSION

PEG-IFN-α2b in itself had remarkable anti-metastatic effects via inhibition of angiogenesis and cell adhesions.

Insulin-like growth factor-binding protein 7 alters the sensitivity to interferon-based anticancer therapy in hepatocellular carcinoma cells

BACKGROUND

A striking efficiency of interferon (IFN)-based anticancer therapy for advanced hepatocellular carcinoma (HCC) has been reported. Because its clinical efficiency greatly depends on each patient's local response, prediction of local response is crucial.

METHODS

Continuous exposure of IFN-alpha to parental PLC/PRF/5 cells (PLC-P) and a limiting dilution method resulted in the establishment of IFN-resistant cell clones (PLC-Rs). Microarray analyses of PLC-P and PLC-Rs identified insulin-like growth factor-binding protein 7 (IGFBP7) as one of the most significantly downregulated genes in PLC-Rs. Changes in anticancer effects of IFN-alpha were examined in HCC cells after genetic manipulation of IGFBP7 expression. The correlation between immunohistochemically determined IGFBP7 expression and the response to IFN-alpha/5-fluorouracil (5-FU) therapy was investigated in surgically resected HCC specimens.

RESULTS

PLC-R cells showed a remarkable downregulation of IGFBP7 and resistance to IFN-alpha, compared with PLC-P. Parental PLC/PRF/5 cells transfected with short hairpin RNA against IGFBP7 showed a significant resistance to IFN-alpha relative to control cells (IC(50) fold increase=14.38 times). Insulin-like growth factor-binding protein 7 transfection into PLC-R restored sensitivity to IFN-alpha. In resected specimens, IGFBP7 expression significantly correlated with the response to IFN-alpha/5-FU therapy.

CONCLUSION

IGFBP7 could be a useful predictor of the response to IFN-based therapy in advanced HCC.

Combination of interferon-alpha and 5-fluorouracil inhibits endothelial cell growth directly and by regulation of angiogenic factors released by tumor cells

Background

The combination therapy of interferon (IFN)-alpha and 5-fluorouracil (5-FU) improved the prognosis of the patients with hepatocellular carcinoma (HCC). To determine the molecular mechanisms of the anti-tumor and anti-angiogenic effects, we examined the direct anti-proliferative effects on human umbilical vein endothelial cells (HUVEC) and indirect effects by regulating secretion of angiogenic factors from HCC cells.

Methods

The direct effects on HUVEC were examined by TUNEL, Annexin-V assays and cell cycles analysis. For analysis of the indirect effects, the apoptosis induced by the conditioned medium from HCC cell treated by IFN-alpha/5-FU and expression of angiogenic factors was examined.

Results

IFN-alpha and 5-FU alone had anti-proliferative properties on HUVEC and their combination significantly inhibited the growth (compared with control, 5-FU or IFN alone). TUNEL and Annexin-V assays showed no apoptosis. Cell cycle analysis revealed that IFN-alpha and 5-FU delayed cell cycle progression in HUVEC with S-phase accumulation. The conditioned medium from HuH-7 cells after treatment with IFN/5-FU significantly inhibited HUVEC growth and induced apoptosis, and contained high levels of angiopoietin (Ang)-1 and low levels of vascular endothelial growth factor (VEGF) and Ang-2. Knockdown of Ang-1 in HuH-7 cells abrogated the anti-proliferative effects on HUVEC while knockdown of Ang-2 partially rescue the cells.

Conclusion

These results suggested that IFN-alpha and 5-FU had direct growth inhibitory effects on endothelial cells, as well as anti-angiogenic effects through regulation of angiogenic factors released from HCC cells. Modulation of VEGF and Angs secretion by IFN-alpha and 5-FU may contribute to their anti-angiogenic and anti-tumor effects on HCC.

Activation of Wnt/beta-catenin signalling pathway induces chemoresistance to interferon-alpha/5-fluorouracil combination therapy for hepatocellular carcinoma

Type I IFN receptor type 2 (IFNAR2) expression correlates significantly with clinical response to interferon (IFN)-α/5-fluorouracil (5-FU) combination therapy for hepatocellular carcinoma (HCC). However, some IFNAR2-positive patients show no response to the therapy. This result suggests the possibility of other factors, which would be responsible for resistance to IFN-α/5-FU therapy. The aim of this study was to examine the mechanism of anti-proliferative effects of IFN-α/5-FU therapy and search for a biological marker of chemoresistance to such therapy. Gene expression profiling and molecular network analysis were used in the analysis of non-responders and responders with IFNAR2-positive HCC. The Wnt/β-catenin signalling pathway contributed to resistance to IFN-α/5-FU therapy. Immunohistochemical analysis showed positive epithelial cell adhesion molecule (Ep-CAM) expression, the target molecule of Wnt/β-catenin signalling, only in non-responders. In vitro studies showed that activation of Wnt/β-catenin signalling by glycogen synthesis kinase-3 inhibitor (6-bromoindirubin-3′-oxime (BIO)) induced chemoresistance to IFN-α/5-FU. BrdU-based cell proliferation ELISA and cell cycle analysis showed that concurrent addition of BIO and IFN-α/5-FU significantly to hepatoma cell cultures reduced the inhibitory effects of the latter two on DNA synthesis and accumulation of cells in the S-phase. The results indicate that activation of Wnt/β-catenin signalling pathway induces chemoresistance to IFN-α/5-FU therapy and suggest that Ep-CAM is a potentially useful marker for resistance to such therapy, especially in IFNAR2-positive cases.

Multiple roles and therapeutic implications of Akt signaling in cancer

The prominence of the PI3K-Akt signaling pathway in several tumors indicates a relationship with tumor grade and proliferation. Critical cellular processes are driven through this pathway. More detailed knowledge of the pathogenesis of tumors would enable us to design targeted drugs to block both membrane tyrosine kinase receptors and the intracellular kinases involved in the transmission of the signal. The newly approved molecular inhibitors sunitinib (an inhibitor of vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and other tyrosine kinase receptors), sorafenib (a serine-threonine kinase inhibitor that acts against B-Raf) and temsirolimus (an mTOR inhibitor) shown clinical activity in advanced kidney cancer. Chronic myeloid leukemia has changed its natural history thanks to imatinib and dasatinib, both of which inhibit the intracellular bcr/abl protein derived from the alteration in the Philadelphia chromosome. Intracellular pathways are still important in cancer development and their blockade directly affects outcome. Cross-talk has been observed but is not well understood. Vertical and horizontal pathway blockade are promising anticancer strategies. Indeed, preclinical and early clinical data suggest that combining superficial and intracellular blocking agents can synergize and leverage single-agent activity. The implication of the Akt signaling pathway in cancer is well established and has led to the development of new anticancer agents that block its activation.

Fas / FasL system, IL-1beta expression and apoptosis in chronic HBV and HCV liver disease

The Fas / Fas-ligand (FasL) system is an important death signal pathway in the liver. An enhanced local inflammatory response prompted by FasL expression, which contributes to neutrophil recruitment and interleukin-1 beta (IL-1beta) release, seems to be crucial to chronic liver damage, persistence of viral infections, and probably initiation and / or promotion of HCC. In order to evaluate the expression of Fas, FasL, and IL-1beta in different stages of human liver disease and to determine whether hepatitis B virus (HBV) and hepatitis C virus (HCV) infections modulate their expression, also in relation to apoptosis, we examined 87 liver samples obtained from patients with: chronic hepatitis (CH) (n.42), cirrhosis (n.9) and hepatocellular carcinoma (HCC) (n.16) and corresponding peritumoural tissues (n.16); histologically-normal liver (n.4) as controls. Fas, FasL and IL-1beta mRNA were quantified using reverse transcriptase-polymerase chain reaction. The apoptotic index was evaluated by TUNEL analysis. Our data showed a progressive Fas / FasL increase from CH to cirrhosis followed by a decline from the latter to HCC. In histological sections apoptosis was detected in HCC. A significant difference emerged between HCV and HBV-related disease for IL-1beta expression only in CH. A significant positive correlation between IL-1beta and FasL in HCV-related disease (P = 0.014) and an inverse correlation between IL-1beta and Fas in HBV-related disease (P = 0.021) were observed. The different pattern of IL-1beta, Fas and FasL expression found in HCV- and HBV-mediated liver disease, points to a different modulation of immune response B and C virus induced, while the decline in Fas / FasL expression in HCC may be related to defence mechanisms adopted by HCC cells against the immune system.

Pilot study of combination chemotherapy of S-1, a novel oral DPD inhibitor, and interferon-alpha for advanced hepatocellular carcinoma with extrahepatic metastasis

BACKGROUND

To the authors' knowledge, there is no effective therapy for extrahepatic metastasis of hepatocellular carcinoma (HCC). In a pilot study, the results of combination therapy of S-1, a novel oral dehydropyrimidine dehydrogenase (DPD) inhibitor, and interferon-alpha (IFN-alpha) are reported for HCC patients with extrahepatic metastasis.

METHODS

Twelve patients with extrahepatic metastasis of HCC were enrolled in the pilot study. S-1 was administered orally at a dose based on body surface area, twice daily after a meal, for 4 weeks. IFN-alpha was injected subcutaneously on Days 1, 3, and 5 of each week. One course consisted of consecutive administration for 28 days followed by 14 days rest.

RESULTS

An objective response was observed in 3 (25%) of 12 patients. The overall 1-year survival rate was 61.7%. Grade 3 leukocytopenia was observed in 1 patient (8.3%). No severe toxicity or treatment-related deaths were observed.

CONCLUSIONS

The combination therapy of S-1 and IFN-alpha appears to be highly efficacious, with low toxicity in patients with extrahepatic metastases of HCC. The combination chemotherapy of oral S-1 and subcutaneous IFN-alpha is a potentially promising treatment strategy for advanced HCC with extrahepatic metastasis.

Interferon-alpha and 5-fluorouracil combination therapy after palliative hepatic resection in patients with advanced hepatocellular carcinoma, portal venous tumor thrombus in the major trunk, and multiple nodules

BACKGROUND

The authors reported previously the beneficial effects of interferon (IFN)-alpha/5-fluorouracil (5-FU) combination therapy for patients with advanced hepatocellular carcinoma (HCC) who have tumor thrombi in the major portal branches. In this report, the authors describe the results from IFN/5-FU chemotherapy for patients who underwent palliative hepatic resection for advanced HCC with tumor thrombus in the main trunk of the portal vein and multiple nodules in the whole liver. In addition, they evaluated the correlation between the response to such therapy and expression of IFN-alpha type 2 receptor (IFNAR2).

METHODS

From October 1999 to December 2004, 30 patients with advanced HCC, tumor thrombi in the main trunk of the portal vein, and multiple nodules in the whole liver (Vp4 and grade 3 intrahepatic metastases) were recruited for this study. They underwent palliative hepatic resection followed by at least 2 courses of IFN/5-FU. IFNAR2 expression levels were determined by immunohistochemistry.

RESULTS

No major treatment-related complications were noted. An objective response was noted in 10 patients (33.3%) and included a complete response in 6 patients (20%), a partial response in 4 patients (13.3%), no response in 1 patient (3.3%), and progressive disease in 19 patients (63.4%). IFNAR2 expression was detected in 20 of 30 patients (66.7%). There was a significant difference in overall survival between patients with positive and negative IFNAR2 expression cases (P<.0025), and a significant correlation was observed between IFNAR2 expression and response to IFN/5-FU combination therapy (P=.0199).

CONCLUSIONS

Adjunct IFN/5-FU therapy is a promising modality for patients with advanced HCC, tumor thrombi in the major trunk, and multiple nodules after palliative hepatic resection. The results from this study indicated that the response to such therapy seemed to be correlated with IFNAR2 expression.