Recent advances in immunotherapy for hepatocellular cancer

Identification of key genes and pathways associated with resting mast cells in meningioma

BACKGROUND

To identify candidate key genes and pathways related to resting mast cells in meningioma and the underlying molecular mechanisms of meningioma.

METHODS

Gene expression profiles of the used microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. GO and KEGG pathway enrichments of DEGs were analyzed using the ClusterProfiler package in R. The protein-protein interaction network (PPI), and TF-miRNA- mRNA co-expression networks were constructed. Further, the difference in immune infiltration was investigated using the CIBERSORT algorithm.

RESULTS

A total of 1499 DEGs were identified between tumor and normal controls. The analysis of the immune cell infiltration landscape showed that the probability of distribution of memory B cells, regulatory T cells (Tregs), and resting mast cells in tumor samples were significantly higher than those in the controls. Moreover, through WGCNA analysis, the module related to resting mast cells contained 158 DEGs, and KEGG pathway analysis revealed that the DEGs were dominant in the TNF signaling pathway, cytokine-cytokine receptor interaction, and IL-17 signaling pathway. Survival analysis of hub genes related to resting mast cells showed that the risk model was constructed based on 9 key genes. The TF-miRNA- mRNA co-regulation network, including MYC-miR-145-5p, TNFAIP3-miR-29c-3p, and TNFAIP3-hsa-miR-335-3p, were obtained. Further, 36 nodes and 197 interactions in the PPI network were identified.

CONCLUSION

The results of this study revealed candidate key genes, miRNAs, and pathways related to resting mast cells involved in meningioma development, providing potential therapeutic targets for meningioma treatment.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Safety and Preliminary Efficacy of Ramucirumab in Combination with FOLFOX4 in Patients with Advanced Hepatocellular Carcinoma: A Nonrandomized, Open-Label, Phase Ib Study

LESSONS LEARNED

The combination of ramucirumab (8 mg/kg intravenous, day 1 every 2 weeks) and FOLFOX4 as first-line treatment in patients with advanced hepatocellular carcinoma (HCC) was not sufficiently tolerated. Preliminary efficacy data suggest that the combination may provide clinical benefit to patients with HCC. Dose modification and patient selection should be considered for the future development of ramucirumab plus FOLFOX chemotherapy for advanced HCC.

BACKGROUND

The objective of this study was to investigate the safety, preliminary efficacy, pharmacokinetics, and immunogenicity of ramucirumab plus FOLFOX4 as first-line treatment in patients with advanced hepatocellular carcinoma (HCC).

METHODS

Patients received ramucirumab (8 mg/kg) intravenously (IV) on day 1, followed by FOLFOX4 (oxaliplatin 85 mg/m2 IV on day 1, folinic acid 200 mg/m2 IV, bolus fluorouracil [5-FU] 400 mg/m2 , and a continuous infusion of 5-FU 600 mg/m2 over 22 hours, on days 1 and 2) every 2 weeks. The primary endpoint was to assess the safety and tolerability of the combination therapy.

RESULTS

Eight patients (6 men, 2 women) were treated; all eight patients experienced at least one treatment-emergent adverse event (TEAE) of grade ≥3. Dose-limiting toxicities occurred in three patients (37.5%): hepatic hemorrhage (grade 4), blood bilirubin increased (grade 3), and febrile neutropenia (grade 3). Two patients discontinued study because of hepatic hemorrhage (grade 4) and blood bilirubin increase (grade 3). Six deaths occurred due to progressive disease, and no deaths due to TEAEs.

CONCLUSION

There were no unexpected safety findings with ramucirumab plus FOLFOX4 based on the known safety and toxicity of this regimen. The combination was not sufficiently tolerated in patients with advanced HCC at the specified dose and schedule.

Alpha-Fetoprotein and Hepatocellular Carcinoma Immunity

Hepatocarcinoma is one of the most prevalent gastroenterological cancers in the world with less effective therapy. As an oncofetal antigen and diagnostic marker for liver cancer, alpha-fetoprotein (AFP) possesses a variety of biological functions. Except for its diagnosis in liver cancer, AFP has become a target for liver cancer immunotherapy. Although the immunogenicity of AFP is weak and it could induce the immune escapes through inhibiting the function of dendritic cells, natural killer cells, and T lymphocytes, AFP has attracted more attention in liver cancer immunotherapy. By in vitro modification, the immunogenicity and immune response of AFP could be enhanced. AFP-modified immune cell vaccine or peptide vaccine has displayed the specific antitumor immunity against AFP-positive tumor cells and laid a better foundation for the immunotherapy of liver cancer.

Immunotherapy against cancer-related viruses

Approximately 12% of all cancers worldwide are associated with viral infections. To date, eight viruses have been shown to contribute to the development of human cancers, including Epstein-Barr virus (EBV), Hepatitis B and C viruses, and Human papilloma virus, among others. These DNA and RNA viruses produce oncogenic effects through distinct mechanisms. First, viruses may induce sustained disorders of host cell growth and survival through the genes they express, or may induce DNA damage response in host cells, which in turn increases host genome instability. Second, they may induce chronic inflammation and secondary tissue damage favoring the development of oncogenic processes in host cells. Viruses like HIV can create a more permissive environment for cancer development through immune inhibition, but we will focus on the previous two mechanisms in this review. Unlike traditional cancer therapies that cannot distinguish infected cells from non-infected cells, immunotherapies are uniquely equipped to target virus-associated malignancies. The targeting and functioning mechanisms associated with the immune response can be exploited to prevent viral infections by vaccination, and can also be used to treat infection before cancer establishment. Successes in using the immune system to eradicate established malignancy by selective recognition of virus-associated tumor cells are currently being reported. For example, numerous clinical trials of adoptive transfer of ex vivo generated virus-specific T cells have shown benefit even for established tumors in patients with EBV-associated malignancies. Additional studies in other virus-associated tumors have also been initiated and in this review we describe the current status of immunotherapy for virus-associated malignancies and discuss future prospects.

Chemosensitization of HepG2 cells by suppression of NF-κB/p65 gene transcription with specific-siRNA

AIM

To investigate small interfering RNA (siRNA)-mediated inhibition of nuclear factor-kappa B (NF-κB) activation and multidrug-resistant (MDR) phenotype formation in human HepG2 cells.

METHODS

Total RNA was extracted from human HepG2 or LO2 cells. NF-κB/p65 mRNA was amplified by nested reverse transcription polymerase chain reaction and confirmed by sequencing. NF-κB/p65 was analyzed by immunohistochemistry. Specific-siRNA was transfected to HepG2 cells to knock down NF-κB/p65 expression. The effects on cell proliferation, survival, and apoptosis were assessed, and the level of NF-κB/p65 or P-glycoprotein (P-gp) was quantitatively analyzed by enzyme-linked immunosorbent assay.

RESULTS

HepG2 cells express NF-κB/p65 and express relatively less phosphorylated p65 (P-p65) and little P-gp. After treatment of HepG2 cells with different doses of doxorubicin, the expression of NF-κB/p65, P-p65, and especially P-gp were dose-dependently upregulated. After HepG2 cells were transfected with NF-κB/p65 siRNA (100 nmol/L), the expression of NF-κB/p65, P-p65, and P-gp were downregulated significantly and dose-dependently. The viability of HepG2 cells was decreased to 23% in the combination NF-κB/p65 siRNA (100 nmol/L) and doxorubicin (0.5 μmol/L) group and 47% in the doxorubicin (0.5 μmol/L) group (t = 7.043, P < 0.001).

CONCLUSION

Knockdown of NF-κB/p65 with siRNA is an effective strategy for inhibiting HepG2 cell growth by downregulating P-gp expression associated chemosensitization and apoptosis induction.

The role of death receptor 3 in the biological behavior of hepatocellular carcinoma cells

Death receptor 3 (DR3) belongs to the tumor necrosis factor (TNF) receptor superfamily, primarily found in lymphoid tissues. Reports have determined that DR3 may also be distributed in numerous types of tumors. Therefore, it is thought that DR3 may have an important role in the process of tumorigenesis. The aim of the present study was to observe the effect of silencing DR3 expression on hepatocarcinoma cell growth, apoptosis and invasion in order to elucidate the role of DR3 in tumor development. The hepatocarcinoma cell lines (HepG2, Huh7, SMMC7721 and Bel-7402) and normal human liver cells (HL-7702) were transfected with three stealth RNA interference (RNAi) sequences that target the DR3 gene. Reverse transcription quantitative polymerase chain reaction was used to detect the expression levels of DR3 in hepatocarcinoma cell lines and normal liver HL-7702 cells. MTT assay and flow cytometry (FCM) were used to determine the rates of cell proliferation and apoptosis, respectively. Following silencing of the DR3 gene, western blot analysis was used to determine the protein expression of P53, Fas, Caspase8, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and Caspase3. DR3 messenger RNA (mRNA) expression in hepatocarcinoma cell lines was significantly increased compared with that in the normal liver cell line. Three targeted DR3 gene small interfering RNAs significantly inhibited DR3 gene expression in Bel-7402 cells at the nucleic acid level. AF02670.1_stealth_883 and cocktail demonstrated the most efficient inhibition of DR3 gene expression at 48 and 72 h following transfection, with mRNA inhibition rates of 89.46 and 92.75%, and 90.53 and 94.25% (P<0.01), respectively. Cell viability was significantly reduced by AF02670.1_stealth_883 and RNAi cocktail at 24, 48 and 72 h following transfection. The inhibition rates of cell proliferation were 50.76 and 61.76% (P<0.05) at 72 h following transfection. FCM revealed that AF02670.1_stealth_883 and RNAi cocktail also induced apoptosis in Bel-7402 cells at 72 h following transfection. Reduction of NF-κB and P53 levels was observed (P<0.05) in Bel-7402 cells following DR3 silencing, whereas levels of Fas, Caspase3 and Caspase8 were markedly elevated (P<0.05). DR3 expression levels in hepatocellular carcinoma cells were significantly higher than those in normal cells. DR3 silencing effectively inhibited proliferation and invasion of hepatocellular carcinoma cells in vitro. However, silencing of the DR3 gene affect levels of apoptosis antigen-3 ligand in cells, therefore indicating that it may be involved with other pathways that regulate apoptosis in HCCs. In conclusion, the results of the present study indicated that DR3 may be a promising therapeutic target molecule for further study of hepatocellular carcinoma gene therapy.

Mycobacterium bovis BCG promotes tumor cell survival from tumor necrosis factor-α-induced apoptosis

Background

Increased incidence of lung cancer among pulmonary tuberculosis patients suggests mycobacteria-induced tumorigenic response in the host. The alveolar epithelial cells, candidate cells that form lung adenocarcinoma, constitute a niche for mycobacterial replication and infection. We thus explored the possible mechanism of M. bovis Bacillus Calmette-Guérin (BCG)-assisted tumorigenicity in type II epithelial cells, human lung adenocarcinoma A549 and other cancer cells.

Methods

Cancer cell lines originating from lung, colon, bladder, liver, breast, skin and cervix were treated with tumor necrosis factor (TNF)-α in presence or absence of BCG infection. p53, COP1 and sonic hedgehog (SHH) signaling markers were determined by immunoblotting and luciferase assays, and quantitative real time PCR was done for p53-responsive pro-apoptotic genes and SHH signaling markers. MTT assays and Annexin V staining were utilized to study apoptosis. Gain- and loss-of-function approaches were used to investigate the role for SHH and COP1 signaling during apoptosis. A549 xenografted mice were used to validate the contribution of BCG during TNF-α treatment.

Results

Here, we show that BCG inhibits TNF-α-mediated apoptosis in A549 cells via downregulation of p53 expression. Substantiating this observation, BCG rescued A549 xenografts from TNF-α-mediated tumor clearance in nude mice. Furthermore, activation of SHH signaling by BCG induced the expression of an E3 ubiquitin ligase, COP1. SHH-driven COP1 targeted p53, thereby facilitating downregulation of p53-responsive pro-apoptotic genes and inhibition of apoptosis. Similar effects of BCG could be shown for HCT116, T24, MNT-1, HepG2 and HELA cells but not for HCT116 p53^-/- and MDA-MB-231 cells.

Conclusion

Our results not only highlight possible explanations for the coexistence of pulmonary tuberculosis and lung cancer but also address probable reasons for failure of BCG immunotherapy of cancers.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-210) contains supplementary material, which is available to authorized users.

Combination of intratumoral invariant natural killer T cells and interferon-gamma is associated with prognosis of hepatocellular carcinoma after curative resection

Purpose

To investigate the prognostic value of intratumoral invariant natural killer T (iNKT) cells and interferon-gamma (IFN-γ) in hepatocellular carcinoma (HCC) after curative resection.

Experimental Design

Expression of TRAV10, encoding the Vα24 domain of iNKT cells, and IFN-γ mRNA were assessed by quantitative real-time polymerase chain reaction in tumor from 224 HCC patients undergoing curative resection. The prognostic value of these two and other clinicopathologic factors was evaluated.

Results

Either intratumoral iNKT cells and IFN-γ alone or their combination was an independent prognostic factor for OS (P = 0.001) and RFS (P = 0.001) by multivariate Cox proportional hazards analysis. Patients with concurrent low levels of iNKT cells and IFN-γ had a hazard ratio (HR) of 2.784 for OS and 2.673 for RFS. The areas under the curve of iNKT cells, IFN-γand their combination were 0.618 vs 0.608 vs 0.654 for death and 0.591 vs 0.604 vs 0.633 for recurrence respectively by receiver operating characteristic curve analysis. The prognosis was the worst for HCC patients with concurrent low levels of iNKT cells and IFN-γ, which might be related with more advanced pTNM stage and more vascular invasion.

Conclusions

Combination of intratumoral iNKT cells and IFN-γ is a promising independent predictor for recurrence and survival in HCC, which has a better power to predict HCC patients’ outcome compared with intratumoral iNKT cells or IFN-γ alone.

Alpha-fetoprotein: a renaissance

Alpha-fetoprotein (AFP) is a major mammalian embryo-specific and tumor-associated protein that is also present in small quantities in adults at normal conditions. Discovery of the phenomenon of AFP biosynthesis in carcinogenesis by G. Abelev and Yu. Tatarinov 50 years ago, in 1963, provoked intensive studies of this protein. AFPs of some mammalian species were isolated, purified and physico-chemically and immunochemically characterized. Despite the significant success in study of AFP, its three-dimensional structure, mechanisms of receptor binding along with a structure of the receptor itself and, what is the most important, its biological role in embryo- and carcinogenesis remain still obscure. Due to difficulties linked with methodological limitations, research of AFP was to some extent extinguished by the 1990 s. However, over the last decade a growing number of investigations of AFP and its usage as a tumor-specific biomarker have been observed. This was caused by the use of new technologies, primarily, computer-based and genetic engineering approaches in studying of this very important oncodevelopmental protein. Our review summarizes efforts of different scientific groups throughout the world in studying AFP for 50 years with emphasis on detailed description of recent achievements in this field.

Hepatocellular carcinoma-specific immunotherapy with synthesized α1,3- galactosyl epitope-pulsed dendritic cells and cytokine-induced killer cells

AIM: To evaluate the safety and clinical efficacy of a new immunotherapy using both α-Gal epitope-pulsed dendritic cells (DCs) and cytokine-induced killer cells.

METHODS: Freshly collected hepatocellular carcinoma (HCC) tumor tissues were incubated with a mixture of neuraminidase and recombinant α1,3-galactosyltransferase (α1,3GT) to synthesize α-Gal epitopes on carbohydrate chains of the glycoproteins of tumor membranes. The subsequent incubation of the processed membranes in the presence of human natural anti-Gal IgG resulted in the effective phagocytosis to the tumor membrane by DCs. Eighteen patients aged 38-78 years with stage III primary HCC were randomLy chosen for the study; 9 patients served as controls, and 9 patients were enrolled in the study group.

RESULTS: The evaluation demonstrated that the procedure was safe; no serious side effects or autoimmune diseases were observed. The therapy significantly prolonged the survival of treated patients as compared with the controls (17.1 ± 2.01 mo vs 10.1 ± 4.5 mo, P = 0.00121). After treatment, all patients in the study group had positive delayed hypersensitivity and robust systemic cytotoxicity in response to tumor lysate as measured by interferon-γ-expression in peripheral blood mononuclear cells using enzyme-linked immunosorbent spot assay. They also displayed increased numbers of CD8-, CD45RO- and CD56-positive cells in the peripheral blood and decreased α-fetoprotein level in the serum.

CONCLUSION: This new tumor-specific immunotherapy is safe, effective and has a great potential for the treatment of tumors.

Dendritic cell-based vaccines positively impact natural killer and regulatory T cells in hepatocellular carcinoma patients

Immunotherapy of cancer must promote antitumor effector cells for tumor eradication as well as counteract immunoregulatory mechanisms which inhibit effectors. Immunologic therapies of cancer are showing promise, including dendritic cell-(DC-) based strategies. DC are highly malleable antigen-presenting cells which can promote potent antitumor immunity as well as tolerance, depending on the environmental signals received. Previously, we tested a peptide-pulsed DC vaccine to promote Alpha-fetoprotein (AFP-) specific anti-tumor immunity in patients with hepatocellular carcinoma (HCC), and reported on the CD8⁺ T cell responses induced by this vaccine and the clinical trial results. Here, we show that the peptide-loaded DC enhanced NK cell activation and decreased regulatory T cells (Treg) frequencies in vaccinated HCC patients. We also extend these data by testing several forms of DC vaccines in vitro to determine the impact of antigen loading and maturation signals on both NK cells and Treg from healthy donors and HCC patients.

Suppression of human hepatoma (HepG2) cell growth by nuclear factor-kappaB/p65 specific siRNA

Nuclear factor-kappaB (NF-κB) is a transcription factor and antagonist of apoptosis during liver regeneration and closely related to the formation and development of hepatocellular carcinoma. In the present study, we investigated the effect of small interference RNA (siRNA)-mediated inhibition of NF-κB on growth of human hepatoma (HepG2) cells. Our data indicated that the expression of NF-κB/p65 mRNA was significantly higher in the HepG2 cells than that in the normal liver (LO2) cells before transfection, and the expression of NF-κB/p65 in the HepG2 cells with NF-κB/p65 siRNA (100 nMol/L) transfection at 72 h was reduced at the levels of mRNA (93%) and protein (62%) using real-time reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting. Interestingly, the apoptosis index of the HepG2 cells increased up to 85%, detected by Annexin V-fluorescein isothiocyanate, suggesting that NF-κB is overexpressed in hepatoma cells and can be inhibited by NF-κB/p65 siRNA through the apoptotic mechanism. Thus, we conclude that NF-κB is a potential molecular target for HCC gene therapy.

Suppression of human hepatoma (HepG2) cell growth by nuclear factor-kappaB/p65 specific siRNA

Nuclear factor-kappaB (NF-κB) is a transcription factor and antagonist of apoptosis during liver regeneration and closely related to the formation and development of hepatocellular carcinoma. In the present study, we investigated the effect of small interference RNA (siRNA)-mediated inhibition of NF-κB on growth of human hepatoma (HepG2) cells. Our data indicated that the expression of NF-κB/p65 mRNA was significantly higher in the HepG2 cells than that in the normal liver (LO2) cells before transfection, and the expression of NF-κB/p65 in the HepG2 cells with NF-κB/p65 siRNA (100 nMol/L) transfection at 72 h was reduced at the levels of mRNA (93%) and protein (62%) using real-time reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blotting. Interestingly, the apoptosis index of the HepG2 cells increased up to 85%, detected by Annexin V-fluorescein isothiocyanate, suggesting that NF-κB is overexpressed in hepatoma cells and can be inhibited by NF-κB/p65 siRNA through the apoptotic mechanism. Thus, we conclude that NF-κB is a potential molecular target for HCC gene therapy.

Beta2-GPI: a novel factor in the development of hepatocellular carcinoma

PURPOSE

This study investigated the effect and clinical significance of beta2-GPI in hepatocellular carcinoma (HCC).

METHODS

Double fluorescent immunostaining analysis was performed in paraffin wax-embedded histological sections of nine HCC parenchyma, seven adjacent non-cancerous tissues and seven control liver tissues from hepatitis B virus (HBV) infected patients using a beta2-GPI polyclonal antibody and a HBV surface antibody. NF-κB activation was assessed by a non-radioactive electrophoretic mobility shift assay (EMSA) and immunofluorescence assay in SMMC-7721 HCC cells exposed to various treatments. The cells were transiently transfected with vectors expressing beta2-GPI (group one), HBsAg (group two), both beta2-GPI and HBsAg (group three), or with a control vector (group four). Untransfected cells (group five) were also used as a control. Alpha fetoprotein (AFP) expressions were also detected by ELISA in all groups.

RESULTS

The highest degree of co-localization of beta2-GPI and HBsAg proteins was seen in the endochylema and occurred at the nuclear border in the cancer tissues. Weak beta2-GPI protein staining was present in the endochylema, with a strong signal for HBsAg protein in HBV control samples. Adjacent non-tumorous liver tissue samples also showed HBsAg staining but stronger beta2-GPI signals in the endochylema. In experiments with SMMC-7721 HCC cells, groups one and two had induced activation of NF-κB with the relative NF-κB DNA-binding activities of 55.84 and 51.12, respectively. However, the highest relative NF-κB DNA-binding activity was observed in group three (80.5). The percentages of cells with NF-κB translocated from the cytoplasm to nucleus in groups one, two, three, four and five compared with total cells were 13.5, 8.7, 24.9, 5.7 and 0.95%, respectively. The mean AFP levels were significantly higher in group three (0.0640 ± 0.0059) than in group five (P < 0.001). It appeared higher in group three than in group one (0.0562 ± 0.0060, P < 0.05) and group four (0.0585 ± 0.0040, P < 0.05), while no significant differences were seen between groups three and two, and between groups four and five.

CONCLUSIONS

Beta2-GPI may play a role in the development of HBV-related HCC by activating NF-κB via interaction of beta2-GPI and HBsAg.