Expression of multidrug resistance-associated protein 3 and cytotoxic T cell responses in patients with hepatocellular carcinoma

Immunotherapy and liver transplantation for hepatocellular carcinoma: Current and future challenges

Despite existing curative options like surgical removal, tissue destruction techniques, and liver transplantation for early-stage hepatocellular carcinoma (HCC), the rising incidence and mortality rates of this global health burden necessitate continuous exploration of novel therapeutic strategies. This review critically assesses the dynamic treatment panorama for HCC, focusing specifically on the burgeoning role of immunotherapy in two key contexts: early-stage HCC and downstaging advanced HCC to facilitate liver transplant candidacy. It delves into the unique immunobiology of the liver and HCC, highlighting tumor-mediated immune evasion mechanisms. Analyzing the diverse immunotherapeutic approaches including checkpoint inhibitors, cytokine modulators, vaccines, oncolytic viruses, antigen-targeting antibodies, and adoptive cell therapy, this review acknowledges the limitations of current diagnostic markers alpha-fetoprotein and glypican-3 and emphasizes the need for novel biomarkers for patient selection and treatment monitoring. Exploring the rationale for neoadjuvant and adjuvant immunotherapy in early-stage HCC, current research is actively exploring the safety and effectiveness of diverse immunotherapeutic approaches through ongoing clinical trials. The review further explores the potential benefits and challenges of combining immunotherapy and liver transplant, highlighting the need for careful patient selection, meticulous monitoring, and novel strategies to mitigate post-transplant complications. Finally, this review delves into the latest findings from the clinical research landscape and future directions in HCC management, paving the way for optimizing treatment strategies and improving long-term survival rates for patients with this challenging malignancy.

Immunotherapy for hepatocellular carcinoma: A promising therapeutic option for advanced disease

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, and its incidence continues to increase. Despite improvements in both medical and surgical therapies, HCC remains associated with poor outcomes due to its high rates of recurrence and mortality. Approximately 50% of patients require systemic therapies that traditionally consist of tyrosine kinase inhibitors. Recently, however, immune checkpoint inhibitors have revolutionized HCC management, providing new therapeutic options. Despite these major advances, the different factors involved in poor clinical responses and molecular pathways leading to resistance following use of these therapies remain unclear. Alternative strategies, such as adoptive T cell transfer, vaccination, and virotherapy, are currently under evaluation. Combinations of immunotherapies with other systemic or local treatments are also being investigated and may be the most promising opportunities for HCC treatment. The aim of this review is to provide updated information on currently available immunotherapies for HCC as well as future perspectives.

Alterations in Hepatocellular Carcinoma-Specific Immune Responses Following Hepatitis C Virus Elimination by Direct-Acting Antivirals

Direct-acting antivirals (DAAs) have recently revolutionized the eradication of chronic hepatitis C virus (HCV) infection. However, the effects of DAAs on the development of hepatocellular carcinoma (HCC) remain unknown. Therefore, the present study aimed to investigate immune responses to HCC influenced by DAAs in HCV-infected patients and elucidate the underlying mechanisms. We compared immune responses to 19 different HCC-related tumor-associated antigen (TAA)-derived peptides and host immune cell profiles before and 24 weeks after a treatment with DAAs in 47 HLA-A24-positive patients. The relationships between the different immune responses and phenotypic changes in immune cells were also examined. The treatment with DAAs induced four types of immune responses to TAAs and markedly altered host immune cell profiles. Prominently, reductions in the frequencies of PD-1+CD4+ and PD-1+CD8+ T cells by DAAs were associated with enhanced immune responses to TAAs. The HCV F protein was identified as contributing to the increased frequency of PD-1+ T cells, which may be decreased after eradication by DAAs. DAAs altered the immune responses of patients to HCC by decreasing the frequency of PD-1-expressing CD4+ and CD8+ T cells.

The Mechanism of Rac1 in Regulating HCC Cell Glycolysis Which Provides Underlying Therapeutic Target for HCC Therapy

Aim

To explore the role of Rac1 on sorafenib resistance in hepatocellular carcinoma.

Methods

CCK-8, wound healing assay, Transwell, and cell cycle assay were used to detect the tumor cells development. Cell viability was assessed by MTT. The glycolytic pathway was revealed by cellular metabolism assays.

Result

We recovered that Rac1 upregulation was related to HCC patients' poorer prognosis. Forced expression of Rac1 promoted cell development and sorafenib chemoresistance in HCC cells. Rac1 inhibitor EHop-016 and sorafenib combination markedly prevented cell viability, G2/M phase cycle arrest, and apoptosis than single therapy. Furthermore, combination therapy decreased glycolysis in HCC cells. In vivo, the tumor growth was significantly prevented by combination therapy single therapy.

Conclusion

Our research declares that Rac1 inhibition could block sorafenib resistance in HCC by decreasing glycolysis, which would provide an underlying target for HCC therapy.

Hepatocellular carcinoma and immunotherapy: Beyond immune checkpoint inhibitors

Hepatocellular carcinoma (HCC) is one of the deadliest and most common malignancies of the liver. Considering the rich immune background of carcinogenesis in HCC, efforts have been focused on further understanding the role of the immune system in tumor suppression and promotion. The utilization of immunotherapy in HCC has led to encouraging results that has translated to longer survival and better quality of life among patients. The development of novel HCC-tailored regimens such as vaccine therapy and adoptive cellular therapy coupled with a deeper understanding of biomarkers predictive of the response to immunotherapy will lead to better treatment outcomes.

Immunomodulatory potential of natural products from herbal medicines as immune checkpoints inhibitors: Helping to fight against cancer via multiple targets

Immunotherapy sheds new light to cancer treatment and is satisfied by cancer patients. However, immunotoxicity, single-source antibodies, and single-targeting stratege are potential challenges to the success of cancer immunotherapy. A huge number of promising lead compounds for cancer treatment are of natural origin from herbal medicines. The application of natural products from herbal medicines that have immunomodulatory properties could alter the landscape of immunotherapy drastically. The present study summarizes current medication for cancer immunotherapy and discusses the potential chemicals from herbal medicines as immune checkpoint inhibitors that have a broad range of immunomodulatory effects. Therefore, this review provides valuable insights into the efficacy and mechanism of actions of cancer immunotherapies, including natural products and combined treatment with immune checkpoint inhibitors, which could confer an improved clinical outcome for cancer treatment.

Immunotherapy for Hepatocellular Carcinoma: A 2021 Update

Hepatocellular carcinoma (HCC) is one of one of the most frequent liver cancers and the fourth leading cause of cancer-related mortality worldwide. Current treatment options such as surgery, neoadjuvant chemoradiotherapy, liver transplantation, and radiofrequency ablation will benefit only a very small percentage of patients. Immunotherapy is a novel treatment approach representing an effective and promising option against several types of cancer. The aim of our study is to present the currently ongoing clinical trials and to evaluate the efficacy of immunotherapy in HCC. In this paper, we demonstrate that combination of different immunotherapies or immunotherapy with other modalities results in better overall survival (OS) and progression-free survival (PFS) compared to single immunotherapy agent. Another objective of this paper is to demonstrate and highlight the importance of tumor microenvironment as a predictive and prognostic marker and its clinical implications in immunotherapy response.

ABC Transporters: Regulation and Association with Multidrug Resistance in Hepatocellular Carcinoma and Colorectal Carcinoma

For most cancers, the treatment of choice is still chemotherapy despite its severe adverse effects, systemic toxicity and limited efficacy due to the development of multidrug resistance (MDR). MDR leads to chemotherapy failure generally associated with a decrease in drug concentration inside cancer cells, frequently due to the overexpression of ABC transporters such as P-glycoprotein (P-gp/MDR1/ABCB1), multidrug resistance-associated proteins (MRPs/ABCCs), and breast cancer resistance protein (BCRP/ABCG2), which limits the efficacy of chemotherapeutic drugs. The aim of this review is to compile information about transcriptional and post-transcriptional regulation of ABC transporters and discuss their role in mediating MDR in cancer cells. This review also focuses on drug resistance by ABC efflux transporters in cancer cells, particularly hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC) cells. Some aspects of the chemotherapy failure and future directions to overcome this problem are also discussed.

Immune cell therapy for hepatocellular carcinoma

Given the success of immune checkpoint inhibitors and chimeric antigen receptor (CAR) T cells in clinical settings, the host immune system plays an important role in the recognition and targeting of tumor cells in cancer immunotherapy. As a result, there have been numerous advancements in immune cell therapy using human immune cells. However, recent evidence suggests that one type of immunotherapy alone is not effective for the treatment of cancer, particularly solid tumors. Thus, effective immunotherapy combinations, such as the combination of checkpoint inhibitors and immune cell therapy, are needed. This review focuses on hepatocellular carcinoma among other solid tumors and discusses the current status and future of immune cell therapy in cancer immunotherapy.

Cellular Immune Responses for Squamous Cell Carcinoma Antigen Recognized by T Cells 3 in Patients with Hepatocellular Carcinoma

BACKGROUND & AIMS

Squamous cell carcinoma antigen recognized by T cells 3 (SART3), a tumor-associated antigen expressed in many cancers, functions in tumor rejection. In this study, we investigated its usefulness as an immunotherapeutic target in hepatocellular carcinoma (HCC).

METHODS

The expression of SART3 in hepatoma cell lines and HCC tissues was investigated by immunofluorescence and immunohistochemical analyses. Two peptides derived from SART3 (SART3109 and SART3315) were used for immunological analysis. T-cell responses were investigated by interferon-gamma (IFN-γ) enzyme-linked immunospot and cytotoxic T lymphocyte (CTL) assays using peripheral blood mononuclear cells (PBMCs) in 47 patients, and tumor-infiltrating lymphocytes in 8 of 47 patients with HCC. The safety of immunotherapy using a SART3-derived peptide was investigated by vaccinations of SART3109 in 12 patients with HCC (trial registration: UMIN000005677).

RESULTS

The immunofluorescence and immunohistochemical analyses showed that SART3 was expressed in six HCC cell lines, and in HCC tissues including of alpha-fetoprotein-negative individuals. SART3-specific CTLs were generated by stimulating PBMCs with the peptides, and they showed cytotoxicity against HCC cells expressing the protein. Of the 47 HCC patients, 25.5% and 10.6% showed significant responses to SART3109 and SART3315, respectively. The infiltration of SART3109-specific IFN-γ-producing CTLs into the tumor site was confirmed. In the vaccination study, no severe adverse events were observed, and the peptide-specific CTLs were newly induced in four of five patients tested.

CONCLUSIONS

SART3 is an immunotherapeutic candidate, and peptides from this antigen may be applied in HCC immunotherapy.

TRIAL REGISTRATION

UMIN000005677.

Phase I trial of multidrug resistance-associated protein 3-derived peptide in patients with hepatocellular carcinoma

Multidrug resistance-associated protein 3 (MRP3) is a carrier-type transport protein belonging to the ABC transporters. In this study, we investigated the safety and immunogenicity of a MRP3-derived peptide (MRP3765) as a vaccine and characterized the MRP3-specific T cell responses induced. Twelve hepatocellular carcinoma (HCC) patients treated with hepatic arterial infusion chemotherapy (HAIC) were enrolled. The MRP3-derived peptide was emulsified in incomplete Freund's adjuvant and administered via subcutaneous immunization three times weekly. No serious adverse drug reactions to the peptide vaccine were observed, and the vaccination was well tolerated. The vaccination induced MRP3-specific immunity in 72.7% of the patients. In a phenotypic analysis, the largest post-vaccinated increase in MRP3-specific T cells was due to an increase in cells with the effector memory phenotype. Among the 12 patients, one patient showed a partial response, nine showed a stable disease, and two showed a progressive disease. The median overall survival time was 14.0 months. In conclusion, the safety, effects of immune boosting, and possible prolongation of overall survival by the MRP3-derived peptide demonstrate the potential of the peptide to provide clinical benefit in HCC patients.

Immunological features of T cells induced by human telomerase reverse transcriptase-derived peptides in patients with hepatocellular carcinoma

Human telomerase reverse transcriptase (hTERT) is a catalytic enzyme required for telomere elongation. In this study, we investigated the safety and immunogenicity of an hTERT-derived peptide (hTERT461) as a vaccine and characterized the hTERT-specific T cell responses induced. Fourteen hepatocellular carcinoma (HCC) patients were enrolled in the study. The hTERT-derived peptide was emulsified in incomplete Freund's adjuvant and administered via subcutaneous immunization three times biweekly. The maximum toxicity observed was grade 2 according to the common terminology criteria and mainly consisted of skin reactions at the site of vaccination. The vaccination induced hTERT-specific immunity in 71.4% of patients and 57.1% of patients administered with hTERT461 peptide-specific T cells could prevent HCC recurrence after vaccination. In phenotypic analysis, the post-vaccinated increase in hTERT-specific T cells was due to an increase in cells with the effector memory phenotype, with the potential to produce multiple cytokines. Seven hTERT-specific T cell receptors were obtained from the vaccinated patients, showing their cytotoxic activities to hTERT-derived peptide-bearing cells. In conclusion, the safety and effects of immune boosting by hTERT461 peptide have shown the potential of the peptide to provide clinical benefits in HCC patients.

Analysis of gene expression profiles as a tool to uncover tumor markers of liver cancer progression in a rat model

Establishing a transcriptomic profile of human hepatocellular liver cancer (HCC) progression is a complex undertaking. A rat model of HCC was employed to develop a transcriptomic profile. Using three interventions, preneoplastic lesions appeared after 30 days and they progressed to HCC by 9 months. Preneoplastic and cancer lesions were characterized for transcriptomic analysis, and RNA from total liver homogenates was obtained at 1, 7, 11 and 16 days after the initiation treatment. RNA from dissected persistent preneoplastic lesions, adjacent tissue or cancer tissue was used for 30 days, and 5, 9, 12 and 18 months. The GeneChip^® Rat Exon 1.0 ST arrays, Partek software and an Affymetrix console were employed for these analyses. LGALS3BP was differentially expressed at each time point, from the initial period, through the preneoplastic evolution period and until the end of cancer progression period. Twelve differentially expressed genes common to the preneoplastic evolution and to the cancer progression period were detected, which included ABCC3. Validation of the microarrays was confirmed by reverse transcription-quantitative polymerase chain reaction of six genes, including LGALS3BP and ABCC3. Of note, the proteins of these two genes are associated with the multidrug response complex, and evasion of immune surveillance and negative regulation of T cell proliferation. This model is useful for identifying candidate genes, and to validate them with regards to determining their relevance in rat HCC progression.

Enhancement of tumor-associated antigen-specific T cell responses by radiofrequency ablation of hepatocellular carcinoma

Radiofrequency ablation (RFA) is one of the treatments for hepatocellular carcinoma (HCC) and is known to enhance host immune response. However, the epitopes to which enhanced immune responses occur, the impact on patient prognosis, and the functions and phenotype of T cells induced are still unclear. To address these issues, we analyzed immune responses before and after RFA in 69 HCC patients using 11 tumor-associated antigen (TAA)-derived peptides that we identified to be appropriate to analyze HCC-specific immune responses. The immune responses were analyzed using enzyme-linked immunospot (ELISPOT) assay and tetramer assays using peripheral blood mononuclear cells. An increase in the number of TAA-specific T cells detected by interferon-γ ELISPOT assays occurred in 62.3% of patients after RFA. The antigens and their epitope to which enhanced T cell responses occur were diverse, and some of them were newly induced. The number of TAA-specific T cells after RFA was associated with the prevention of HCC recurrence, and it was clarified to be predictive of HCC recurrence after RFA by univariate and multivariate analyses. The number of TAA-specific T cells after RFA was inversely correlated with the frequency of CD14+ HLA-DR(-/low) myeloid-derived suppressor cells (MDSCs). The modification of T cell phenotype was observed after RFA. The number of TAA-specific T cells at 24 weeks after RFA was decreased.

CONCLUSION

Although RFA can enhance various TAA-specific T cell responses and the T cells induced contribute to the HCC recurrence-free survival of patients, besides immunosuppression by MDSCs, the memory phenotype and lifetime of TAA-specific T cells are not sufficient to prevent HCC recurrence completely. Additional treatments by vaccine or immunomodulatory drugs might be useful to improve the immunological effect of RFA.

Immunotherapy: a useful strategy to help combat multidrug resistance

Multidrug resistance (MDR) renders cancer cells relatively invulnerable to treatment with many standard cytotoxic anti-cancer agents. Cancer immunotherapy could be an important adjunct for other strategies to treat MDR positive cancers, as resistance to immunotherapy generally is unrelated to mechanisms of resistance to cytotoxic agents. Immunotherapy to combat MDR positive tumors could use any of the following strategies: direct immune attack against MDR positive cells, using MDR as an immune target to deliver cytotoxic agents, capitalization on other immune properties of MDR positive cells, or conditional immunotoxins expressed under MDR control. Additional insights into the immunogenic potential of some cytotoxic agents can also be brought to bear on these strategies. This review will highlight key concepts in cancer immunotherapy and illustrate immune principles and strategies that have been or could be used to help destroy MDR positive tumor cells, either alone or in rational combinations.

Adenosine triphosphate-binding cassette transporter genes up-regulation in untreated hepatocellular carcinoma is mediated by cellular microRNAs

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are drug efflux pumps responsible for the multidrug resistance phenotype causing hepatocellular carcinoma (HCC) treatment failure. Here we studied the expression of 15 ABC transporters relevant for multidrug resistance in 19 paired HCC patient samples (16 untreated, 3 treated by chemotherapeutics). Twelve ABC transporters showed up-regulation in HCC compared with adjacent healthy liver. These include ABCA2, ABCB1, ABCB6, ABCC1, ABCC2, ABCC3, ABCC4, ABCC5, ABCC10, ABCC11, ABCC12, and ABCE1. The expression profile and function of some of these transporters have not been associated with HCC thus far. Because cellular microRNAs (miRNAs) are involved in posttranscriptional gene silencing, we hypothesized that regulation of ABC expression in HCC might be mediated by miRNAs. To study this, miRNAs were profiled and dysregulation of 90 miRNAs was shown in HCC compared with healthy liver, including up-regulation of 11 and down-regulation of 79. miRNA target sites in ABC genes were bioinformatically predicted and experimentally verified in vitro using luciferase reporter assays. In total, 13 cellular miRNAs were confirmed that target ABCA1, ABCC1, ABCC5, ABCC10, and ABCE1 genes and mediate changes in gene expression. Correlation analysis between ABC and miRNA expression in individual patients revealed an inverse relationship, providing an indication for miRNA regulation of ABC genes in HCC.

CONCLUSION

Up-regulation of ABC transporters in HCC occurs prior to chemotherapeutic treatment and is associated with miRNA down-regulation. Up-regulation of five ABC genes appears to be mediated by 13 cellular miRNAs in HCC patient samples. miRNA-based gene therapy may be a novel and promising way to affect the ABC profile and overcome clinical multidrug resistance.

Prolonged recurrence-free survival following OK432-stimulated dendritic cell transfer into hepatocellular carcinoma during transarterial embolization

Despite curative locoregional treatments for hepatocellular carcinoma (HCC), tumour recurrence rates remain high. The current study was designed to assess the safety and bioactivity of infusion of dendritic cells (DCs) stimulated with OK432, a streptococcus-derived anti-cancer immunotherapeutic agent, into tumour tissues following transcatheter hepatic arterial embolization (TAE) treatment in patients with HCC. DCs were derived from peripheral blood monocytes of patients with hepatitis C virus-related cirrhosis and HCC in the presence of interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor and stimulated with 0·1 KE/ml OK432 for 2 days. Thirteen patients were administered with 5 × 10⁶ of DCs through arterial catheter during the procedures of TAE treatment on day 7. The immunomodulatory effects and clinical responses were evaluated in comparison with a group of 22 historical controls treated with TAE but without DC transfer. OK432 stimulation of immature DCs promoted their maturation towards cells with activated phenotypes, high expression of a homing receptor, fairly well-preserved phagocytic capacity, greatly enhanced cytokine production and effective tumoricidal activity. Administration of OK432-stimulated DCs to patients was found to be feasible and safe. Kaplan-Meier analysis revealed prolonged recurrence-free survival of patients treated in this manner compared with the historical controls (P = 0·046, log-rank test). The bioactivity of the transferred DCs was reflected in higher serum concentrations of the cytokines IL-9, IL-15 and tumour necrosis factor-α and the chemokines CCL4 and CCL11. Collectively, this study suggests that a DC-based, active immunotherapeutic strategy in combination with locoregional treatments exerts beneficial anti-tumour effects against liver cancer.

Regulation of hepatic ABCC transporters by xenobiotics and in disease states

The subfamily of ABCC transporters consists of 13 members in mammals, including the multidrug resistance-associated proteins (MRPs), sulfonylurea receptors (SURs), and the cystic fibrosis transmembrane conductance regulator (CFTR). These proteins play roles in chemical detoxification, disposition, and normal cell physiology. ABCC transporters are expressed differentially in the liver and are regulated at the transcription and translation level. Their expression and function are also controlled by post-translational modification and membrane-trafficking events. These processes are tightly regulated. Information about alterations in the expression of hepatobiliary ABCC transporters could provide important insights into the pathogenesis of diseases and disposition of xenobiotics. In this review, we describe the regulation of hepatic ABCC transporters in humans and rodents by a variety of xenobiotics, under disease states and in genetically modified animal models deficient in transcription factors, transporters, and cell-signaling molecules.

Enhancement of tumor-specific T-cell responses by transcatheter arterial embolization with dendritic cell infusion for hepatocellular carcinoma

Transcatheter arterial embolization (TAE) destroys a tumor by the induction of necrosis and/or apoptosis and causes inflammation with cytokine production, which may favor immune activation and presentation of tumor-specific antigens. In the current study, we attempted to identify the effect of TAE on tumor-specific T-cell responses and the additional effect of dendritic cell (DC) infusion performed during TAE. The prevalence of tumor antigen-specific T cells was determined by interferon-gamma enzyme-linked immunospot analysis using alpha-fetoprotein (AFP) and tumor antigen-derived peptides in 20 and 13 patients with hepatocellular carcinoma (HCC) who received TAE and TAE with DC infusion, respectively. The increased frequency of AFP-specific T cells was observed in 6 of 20 patients after TAE. It was observed more frequently in patients with DC infusion than in those with TAE alone. However, tumor recurrence was not completely prevented in patients albeit displayed enhanced immune responses. The evidence that the enhanced immune responses were transient and attenuated within 3 months was provided in time-course analysis. In conclusion, TAE with DC infusion enhances the tumor-specific immune responses more effectively than TAE alone. Although the effect is not sufficient to prevent HCC recurrence, these results may contribute to the development of novel immunotherapeutic approach for HCC.