Unmasking of alpha-fetoprotein-specific CD4(+) T cell responses in hepatocellular carcinoma patients undergoing embolization

Immunotherapy in hepatocellular carcinoma: Combination strategies

Liver cancer is one of the most common causes of cancer death globally, and its incidence in the United States is increasing. Patients with advanced hepatocellular carcinoma (HCC) who are not candidates for surgical resection, liver transplant, or locoregional therapies can be treated with systemic therapies. Multiple agents, including sorafenib, lenvatinib, and regorafenib are approved for use as either first- or second-line therapy in this patient population, but all have relatively modest survival benefits. HCC is potentially susceptible to therapy with checkpoint inhibitors, including agents such as nivolumab and pembrolizumab, which are both approved by the Food and Drug Administration for patients previously treated with sorafenib but have not demonstrated superior overall survival in phase III trials. It is clear that more effective approaches are needed to potentiate the effects of checkpoint inhibitors in patients with HCC. This review will outline and appraise the current literature on the use of checkpoint inhibitors in HCC as part of a combination treatment involving an additional mode of therapy. The list of agents that can be paired with checkpoint inhibitors includes an additional checkpoint inhibitor, vascular endothelial growth factor or vascular endothelial growth factor receptor inhibitors, tyrosine kinase inhibitors, OX-40 agonists, and PT-112 inhibitors. The main non-pharmacologic therapies currently being studied for inclusion in a combination strategy include radiation therapy, trans-arterial chemoembolization, and ablation.

Liver, Tumor and Viral Hepatitis: Key Players in the Complex Balance Between Tolerance and Immune Activation

Liver cancer is the third most common cause of cancer related death in the World. From an epidemiological point of view the risk factors associated to primary liver cancer are mainly viral hepatitis infection and alcohol consumption. Even though there is a clear correlation between liver inflammation, cirrhosis and cancer, other emerging liver diseases (like fatty liver) could also lead to liver cancer. Moreover, the liver is the major site of metastasis from colon, breast, ovarian and other cancers. In this review we will address the peculiar status of the liver as organ that has to balance between tolerance and immune activation. We will focus on macrophages and other key cellular components of the liver microenvironment that play a central role during tumor progression. We will also discuss how current and future therapies may affect the balance toward immune activation.

Recent Advances in Immunotherapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death since most patients are diagnosed at advanced stage and the current systemic treatment options using molecular-targeted drugs remain unsatisfactory. However, the recent success of cancer immunotherapies has revolutionized the landscape of cancer therapy. Since HCC is characterized by metachronous multicentric occurrence, immunotherapies that induce systemic and durable responses could be an appealing treatment option. Despite the suppressive milieu of the liver and tumor immunosurveillance escape mechanisms, clinical studies of checkpoint inhibitors in patients with advanced HCC have yielded promising results. Here, we provide an update on recent advances in HCC immunotherapies. First, we describe the unique tolerogenic properties of hepatic immunity and its interaction with HCC and then review the status of already or nearly available immune checkpoint blockade-based therapies as well as other immunotherapy strategies at the preclinical or clinical trial stage.

A novel α-fetoprotein-derived helper T-lymphocyte epitope with strong immunogenicity in patients with hepatocellular carcinoma

α-Fetoprotein (AFP) is considered a good target for immunotherapy strategies against hepatocellular carcinoma (HCC); however, no immunodominant AFP-derived MHC class II-restricted helper T-lymphocyte (HTL) epitope has been reported. Therefore, we identified novel AFP-derived HTL epitopes possessing high immunogenicity. HTL epitopes were predicted using the online service, and peptides were subsequently synthesized. Four newly synthesized peptides showed positive reactivity in >20% patients on ELISPOT using peripheral blood mononuclear cells (PBMCs). Among these, the highest rate was shown by AFP₁ (MKWVESIFLIFLLNFTESRT), which also showed the highest positive rate in cell proliferation assays. Binding assays demonstrated that AFP₁ had strong binding properties toward MHC molecules. Further, blocking assays performed using an anti-HLA-DR antibody showed that immune response decreased, confirming the binding of AFP₁ to HLA-DR molecules. Furthermore, the survival rates of patients with stages II–IV HCC indicated that T cell response against AFP₁ led to significantly greater survival that of patients without T cell response. When evaluating immune response against AFP₁ before and after HCC treatment, an increase in the frequency of peptide-specific T cells was observed after treatment in patients with HLA-DRB1*1502, *0405, and *0901 alleles. In conclusion, the identified epitopes may be useful for immunotherapy strategies against HCC.

Retrospective analysis of the immunogenic effects of intra-arterial locoregional therapies in hepatocellular carcinoma: a rationale for combining selective internal radiation therapy (SIRT) and immunotherapy

Background

Immunotherapy represents a promising option for treatment of hepatocellular carcinoma (HCC) in cirrhotic patients but its efficacy is currently inconsistent and unpredictable. Locoregional therapies inducing immunogenic cell death, such as transarterial chemoembolization (TACE) or selective internal radiation therapy (SIRT), have the potential to act synergistically with immunotherapy. For the development of new approaches combining locoregional treatments with immunotherapy, a better understanding of the respective effects of TACE and SIRT on recruitment and activation of immune cells in HCC is needed. To address this question, we compared intra-tumor immune infiltrates in resected HCC after preoperative treatment with TACE or SIRT.

Methods

Data fromr patients undergoing partial hepatectomy for HCC, without preoperative treatment (SURG, n = 32), after preoperative TACE (TACE, n = 16), or preoperative SIRT (n = 12) were analyzed. Clinicopathological factors, tumor-infiltrating lymphocytes (TILs), CD4⁺ and CD8⁺ T cells, and granzyme B (GZB) expression in resected HCC, and postoperative overall and progression-free survival were compared between the three groups.

Results

Clinicopathological and surgical characteristics were similar in the three groups. A significant increase in TILs, CD4⁺ and CD8⁺ T cells, and GZB expression was observed in resected HCC in SIRT as compared to TACE and SURG groups. No difference in immune infiltrates was observed between TACE and SURG patients. Within the SIRT group, the dose of irradiation affected the type of immune infiltrate. A significantly higher ratio of CD3⁺ cells was observed in the peri-tumoral area in patients receiving < 100 Gy, whereas a higher ratio of intra-tumoral CD4⁺ cells was observed in patients receiving > 100 Gy. Postoperative outcomes were similar in all groups. Irrespective of the preoperative treatment, the type and extent of immune infiltrates did not influence postoperative survival.

Conclusions

SIRT significantly promotes recruitment/activation of intra-tumor effector-type immune cells compared to TACE or no preoperative treatment. These results suggest that SIRT is a better candidate than TACE to be combined with immunotherapy for treatment of HCC. Evaluation of the optimal doses for SIRT for producing an immunogenic effect and the type of immunotherapy to be used require further evaluation in prospective studies.

The Immune Modulation Effect of Locoregional Therapies and Its Potential Synergy with Immunotherapy in Hepatocellular Carcinoma

Locoregional therapies (LRTs) including radiofrequency ablation, surgical resection, and TACE, play a pivotal role in the treatment of early stage/locally advanced hepatocellular carcinoma (HCC). Besides their direct effect on tumor cells, LRTs also play an essential role in the immunomodulation of the tumor microenvironment which is of interest in the current era of cancer immunotherapy. In this review, we describe the HCC immune microenvironment and how it is affected by LRTs as described in multiple pre-clinical and clinical studies and provide the rationale for combining LRTs with immunotherapy.

Hepatic Arterial Bland Embolization Increases Th17 Cell Infiltration in a Syngeneic Rat Model of Hepatocellular Carcinoma

PURPOSE

To determine the tumor immune cell landscape after transcatheter arterial bland embolization (TAE) in a clinically relevant rat hepatocellular carcinoma (HCC) model.

MATERIALS AND METHODS

Buffalo rats (n = 21) bearing syngeneic McArdle RH-7777 rat hepatoma cells implanted into the left hepatic lobe underwent TAE using 70-150 µm beads (n = 9) or hepatic artery saline infusion (n = 12). HCC nodules, peritumoral margin, adjacent non-cancerous liver, and splenic parenchyma were collected and disaggregated to generate single-cell suspensions for immunological characterization 14 d after treatment. Changes in tumor-infiltrating immune subsets including CD4 T cells (Th17 and Treg), CD8 cytotoxic T cells (IFNγ), and neutrophils were evaluated by multiparameter flow cytometry. Migration and colony formation assays were performed to examine the effect of IL-17, a signature cytokine of Th17 cells, on McArdle RH-7777 hepatoma cells under conditions simulating post-embolization environment (i.e., hypoxia and nutrient privation). Statistical significance was determined by the Student unpaired t test or one-way ANOVA.

RESULTS

TAE induces increased infiltration of Th17 cells in liver tumors when compared with controls 14 d after treatment (0.29 ± 0.01 vs. 0.19 ± 0.02; p = 0.02). A similar pattern was observed in the spleen (1.41 ± 0.13 vs. 0.57 ± 0.08; p < 0.001), indicating both local and systemic effect. No significant differences in the percentage of FoxP3 + Tregs, IFNγ-producing CD4 T cells, and CD8 T cells were observed between groups (p > 0.05). In vitro post-embolization assays demonstrated that IL-17 reduces McA-RH7777 cell migration at 24-48 h (p = 0.003 and p = 0.002, respectively).

CONCLUSION

Transcatheter hepatic arterial bland embolization induces local and systemic increased infiltration of Th17 cells and expression of their signature cytokine IL-17. In a simulated post-embolization environment, IL-17 significantly reduced McA-RH7777 cell migration.

Association of TIM-3 with BCLC Stage, Serum PD-L1 Detection, and Response to Transarterial Chemoembolization in Patients with Hepatocellular Carcinoma

Considering the increasing importance of immune checkpoints in tumor immunity we investigated the clinical relevance of serum T-cell immunoglobulin and mucin domain-3 (TIM-3) in patients with hepatocellular carcinoma (HCC). Serum TIM-3 levels were measured and their association with HCC stage and the detection of serum programmed death ligand-1 (PD-L1) were assessed. In patients submitted to transarterial chemoembolization (TACE), pre- and 1-week post-treatment TIM-3 levels were also evaluated. We studied 53 HCC patients with BCLC stages: 0 (5.7%), A (34%), B (32.1%), C (22.6%), and D (5.7%). The patients with advanced HCC (BCLC C) had significantly higher TIM-3 levels than patients with BCLC A (p = 0.009) and BCLC B (p = 0.019). TIM-3 levels were not associated with HCC etiology (p = 0.183). PD-L1 detection (9/53 patients) correlated with TIM-3 levels (univariate analysis, p = 0.047). In 33 patients who underwent TACE, post-treatment TIM-3 levels (231 pg/mL, 132–452) were significantly higher than pre-TACE levels (176 pg/mL, 110–379), (p = 0.036). Complete responders had higher post-TACE TIM-3 levels (534 pg/mL, 370–677) than partial responders (222 pg/mL, 131–368), (p = 0.028). Collectively, TIM-3 may have a role in anti-tumor immunity following TACE, setting a basis for combining immunotherapy and chemoembolization.

Developments in predictive biomarkers for hepatocellular carcinoma therapy

Introduction: Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and the third largest cause of cancer-relateddeaths worldwide. Potentially curative treatments (surgical resection, radiofrequency or liver transplantation) are only available for few patients, while transarterial chemoembolization (TACE) or systemic agents are the best treatments for intermediate and advanced stage disease. The identification of markers that allow us to choose the best treatment for the patient is urgent.Areas covered: In this review we summarize the potential biological markers to predict the efficacy of all treatment available in patients with HCC and discuss anew biomarker with ahigher potential of success in the next future.Expert opinion: HCC is aheterogeneous disease. Tumors are heterogeneous in terms of genetic alteration,with spatial heterogeneity in cellular density, necrosis and angiogenesis.This heterogeneity may affect prognosis and treatment. Tumor heterogeneity can be difficult to quantify with traditional imaging due to subjective assessment of images; the same for sampling biopsy, which evaluates only asmall part of the tumor. We think that combining multi-OMICSwith radiomics represents apromising strategy for evaluating tumor heterogenicity and for identifying biomarkers of response and prognosis.

Inefficient induction of circulating TAA-specific CD8+ T-cell responses in hepatocellular carcinoma

Background & Aims: In hepatocellular carcinoma (HCC), CD8+ T-cell responses targeting tumor-associated antigens (TAA) are considered to be beneficial. However, the molecular profile of TAA-specific CD8+ T cells in HCC is not well defined due to their low frequency.

Results: In this study, we demonstrate that TAA-specific CD8+ T-cell responses are not efficiently induced in the peripheral blood of HCC patients as supported by the following observations: First, in HCC patients, frequencies of TAA-specific CD8+ T cells were not increased compared to healthy donors (HD) or patients with liver cirrhosis. Second, a remarkable proportion of TAA-specific CD8+ T cells were naïve despite the presence of antigen within the tumor tissue. Third, antigen-experienced TAA-specific CD8+ T cells lack the characteristic transcriptional regulation of exhausted CD8+ T cells, namely Eomes^hiTbet^dim, and express inhibitory receptors only on a minor proportion of cells. This suggests restricted antigen recognition and further supports the hypothesis of inefficient induction and activation.

Methods: By applying peptide/MHCI tetramer-based enrichment, a method of high sensitivity, we now could define the heterogeneity of circulating TAA-specific CD8+ T cells targeting glypican-3, NY-ESO-1, MAGE-A1 and MAGE-A3. We focused on therapy-naïve HCC patients of which the majority underwent transarterial chemoembolization (TACE).

Conclusion: Our analysis reveals that circulating TAA-specific CD8+ T cells targeting 4 different immunodominant epitopes are not properly induced in therapy-naïve HCC patients thereby unravelling new and unexpected insights into TAA-specific CD8+ T-cell biology in HCC. This clearly highlights severe limitations of these potentially anti-tumoral T cells that may hamper their biological and clinical relevance in HCC.

Novel immunotherapy strategies for hepatobiliary cancers

Despite recent advancements in therapeutic options for advanced hepatobiliary cancers, there remains an unmet need for innovative systemic treatments. Immunotherapy has shown an ability to provide prolonged clinical benefit, but this benefit remains limited to a small subset of patients. Numerous ongoing endeavors are investigating novel immunotherapy concepts. Immunotherapies that have demonstrated clinical efficacy in hepatobiliary cancers include PD-1 inhibitor therapy and CTLA-4 inhibitor therapy. Novel immunotherapy concepts include targeting emerging checkpoint proteins, bispecific T-cell engagers, combinatorial trials with checkpoint inhibitors, oncolytic virotherapy and chimeric antigen receptor T cells. The goal for these new treatment strategies is to achieve a meaningful expansion of patients deriving prolonged clinical benefit from immunotherapy.

Safety of Combined Yttrium-90 Radioembolization and Immune Checkpoint Inhibitor Immunotherapy for Hepatocellular Carcinoma

PURPOSE

To investigate the safety of yttrium-90 radioembolization in combination with checkpoint inhibitor immunotherapy for the treatment of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

This single-center retrospective study included 26 consecutive patients with HCC who received checkpoint inhibitor immunotherapy within 90 days of radioembolization from April 2015 to May 2018. Patients had preserved liver function (Child-Pugh scores A-B7) and either advanced HCC due to macrovascular invasion or limited extrahepatic disease (21 patients) or aggressive intermediate stage HCC that resulted in earlier incorporation of systemic immunotherapy (5 patients). Clinical documentation, laboratory results, and imaging results at 1- and 3-month follow-up intervals were reviewed to assess treatment-related adverse events and treatment responses.

RESULTS

The median follow-up period after radioembolization was 7.8 months (95% confidence interval [CI], 5.6-11.8). There were no early (30-day) mortality or grades 3/4 hepatobiliary or immunotherapy-related toxicities. Delayed grades 3/4 hepatobiliary toxicities (1-3 months) occurred in 2 patients in the setting of HCC disease progression. One patient developed pneumonitis. The median overall survival from first immunotherapy was 17.2 months (95% CI, 10.9-23.4). The median overall survival from first radioembolization was 16.5 months (95% CI, 6.6-26.4). From first radioembolization, time to tumor progression was 5.7 months (95% CI, 4.2-7.2), and progression-free survival was 5.7 months (95% CI, 4.3-7.1).

CONCLUSIONS

Radioembolization combined with checkpoint inhibitor immunotherapy in cases of HCC appears to be safe and causes limited treatment-related toxicity. Future prospective studies are needed to identify the optimal combination treatment protocols and evaluate the efficacy of combination therapy.

Phase 2 study of pembrolizumab and circulating biomarkers to predict anticancer response in advanced, unresectable hepatocellular carcinoma

BACKGROUND

Checkpoint inhibitors have shown modest activity in patients with advanced hepatocellular carcinoma (HCC). Herein, the authors report a prospective single-institution clinical/translational phase 2 study of pembrolizumab in patients with advanced HCC and circulating biomarkers closely related to response.

METHODS

Pembrolizumab was administered at a dose of 200 mg intravenously every 3 weeks among patients who may have developed disease progression while receiving, were intolerant of, or refused sorafenib. The circulating levels of cytokines, chemokines, programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), and PD-L2 were correlated with response, tumor PD-L1 expression, and other clinicopathological features.

RESULTS

A total of 29 patients were treated and 28 patients were evaluable for response. The most common laboratory grade 3/4 adverse events were increases in aspartate aminotransferase and/or alanine aminotransferase and serum bilirubin, which for the most part were reversible. In terms of efficacy, one patient achieved a complete response and 8 patients achieved partial responses for an overall response rate of 32%. Four other patients had stable disease. The median progression-free survival was 4.5 months and the median overall survival was 13 months. Response did not correlate with prior sorafenib therapy, PD-L1 tumor staining, or a prior history of hepatitis. Correlative studies revealed that high baseline plasma TGF-β levels (≥200 pg/mL) significantly correlated with poor treatment outcomes after pembrolizumab. Tumor PD-L1 and plasma PD-L1/PD-1 levels were associated with plasma IFN-γ or IL-10.

CONCLUSIONS

Pembrolizumab was found to demonstrate activity in patients with advanced HCC. Toxicity generally was tolerable and reversible. A set of immunological markers in blood plasma as well as PD-L1 staining indicated that baseline TGF-β could be a predictive biomarker for response to pembrolizumab.

Combined locoregional-immunotherapy for liver cancer

Locoregional therapies are commonly used to treat patients with hepatocellular carcinoma. It has been noted for many years that locoregional therapies may have additional systemic effects other than simple tumour elimination. Immunological "side effects" have been described in response to locoregional therapies in animal studies and in patients. With the advent of immunotherapy for hepatocellular carcinoma, there is increasing interest in determining the best way to combine immunotherapy with locoregional therapies. Herein, we provide a compact summary of answered and unanswered questions in the field, including: What animal model is best suited to test combined immune-locoregional treatments? How does tumour cell death affect immune responses? What type of immune responses have been observed in patients treated with different types of locoregional therapies? What can be surmised from the results of the first study testing the combination of locoregional therapy with immune checkpoint blockade? Finally, we discuss the outlook for this rapidly growing area of research, focussing on the issues which must be overcome to bridge the gap between interventional radiology and cancer immunology.

Immunotherapy and the Interventional Oncologist: Challenges and Opportunities-A Society of Interventional Oncology White Paper

Interventional oncology is a subspecialty field of interventional radiology that addresses the diagnosis and treatment of cancer and cancer-related problems by using targeted minimally invasive procedures performed with image guidance. Immuno-oncology is an innovative area of cancer research and practice that seeks to help the patient's own immune system fight cancer. Both interventional oncology and immuno-oncology can potentially play a pivotal role in cancer management plans when used alongside medical, surgical, and radiation oncology in the care of cancer patients.

Prospects for immunotherapy as a novel therapeutic strategy against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly aggressive malignant disease, with a poor clinical prognosis. Many standard therapies are often considered for HCC treatment today; however, these conventional therapies often fail to achieve sufficiently effective clinical results. Today, HCC therapy is set to undergo a major revolution, owing to rapid developments in cancer immunotherapy, particularly immune checkpoint inhibitor therapy. Cancer immunotherapy is a novel and promising treatment strategy that differs significantly from conventional therapies in its approach to achieve antitumor effects. In fact, many cancer immunotherapies have been tested worldwide and shown to be effective against various types of cancer; HCC is no exception to this trend. For example, we identified a specific cancer antigen called glypican-3 (GPC3) and performed clinical trials of GPC3-targeted peptide vaccine immunotherapy in patients with HCC. Here, we present an overview of the immune mechanisms for development and progression of HCC, our GPC3-based immunotherapy, and immune checkpoint inhibitor therapy against HCC. Finally, we discuss the future prospects of cancer immunotherapy against HCC. We believe that this review and discussion of cancer immunotherapy against HCC could stimulate more interest in this promising strategy for cancer therapy and help in its further development.

Immune Checkpoint Inhibitors in Hepatocellular Carcinoma: Opportunities and Challenges

Hepatocellular carcinoma (HCC) is the most common malignancy worldwide, and is especially common in China. A total of 70%-80% of patients are diagnosed at an advanced stage and can receive only palliative care. Sorafenib has been the standard of care for a decade, and promising results for regorafenib as a second-line and lenvatinib as a first-line treatment were reported only 1 or 2 years ago. FOLFOX4 was recently recommended as a clinical practice guideline by the China Food and Drug Administration. All approved systemic therapies remain unsatisfactory, with limited objective response rates and poor overall survival. Immune checkpoint inhibitors (CPIs) offer great promise in the treatment of a rapidly expanding spectrum of solid tumors. Immune checkpoint molecules are involved in almost the whole process of viral-related hepatitis with cirrhosis and HCC and in the most important resistance mechanism of sorafenib. The approval of nivolumab by the U.S. Food and Drug Administration on September 23, 2017, for the treatment of patients with HCC, based only on a phase I/II clinical trial, is a strong hint that immunotherapy will introduce a new era of HCC therapy. CPI-based strategies will soon be a main approach in anticancer treatment for HCC, and we will observe the rapid advances in the therapeutic use of CPIs, even in an adjuvant setting, with great interest. How shall we face the opportunities and challenges? Can we dramatically improve the prognosis of patients with HCC? This review may provide some informed guidance. IMPLICATIONS FOR PRACTICE: Immune checkpoint molecules are involved in almost the whole process of viral-related hepatitis with cirrhosis and hepatocellular carcinoma (HCC) and in the most important resistance mechanism of sorafenib. As all approved systemic therapies in HCC remain unsatisfactory, checkpoint inhibitor (CPI)-based strategies will soon be a main approach in anticancer treatment for advanced stage of HCC, even in an adjuvant setting. In virus-related HCC, especially hepatitis B virus-related HCC, whether CPIs can control virus relapse should be further investigated. Combination strategies involving conventional therapies and immunotherapies are needed to increase clinical benefit and minimize adverse toxicities with regard to the underlying liver disease.

Changes in the frequency of myeloid-derived suppressor cells after transarterial chemoembolization with gelatin sponge microparticles for hepatocellular carcinoma

Purpose

A series of clinical studies have established the safety and efficacy of transcatheter arterial chemoembolization (TACE) with gelatin sponge microparticles (GSMs) in treating hepatocellular carcinoma (HCC). HCC can lead to obvious necrosis inside tumors, especially larger ones, although it is unclear whether such necrotic tumor tissue can induce favorable immune reactions against the tumor. Myeloid-derived suppressor cells (MDSCs) have immunosuppressive functions and are currently considered a very important cell type affecting tumor immunity. This study observed changes in MDSC frequency in peripheral blood before and after GSM–TACE to evaluate the effect on the immune function of HCC patients.

Methods

Eight patients diagnosed with HCC underwent GSM–TACE treatment in the Hepatobiliary Interventional Department of Beijing Tsinghua Chang Gung Hospital, Beijing, China; we followed up with the patients over a period of 30 days post-surgery. We used flow cytometry (FCM) to quantify the frequency of MDSCs in peripheral blood before TACE, 10 days after surgery and 30 days after surgery.

Results

MDSC frequency after GSM–TACE had a significant downward trend. Pre-TACE, it was 30.73% ± 11.93%, decreasing to 18.60% ± 11.37% at 10 days after operation. This decrease was not statistically significant (P > 0.05). MDSC frequency was even lower 30 days after TACE (7.63% ± 7.32%) than at 10 days after TACE (P < 0.05), and there was a significant difference compared with pre-TACE (P < 0.001). We evaluated tumor response at 30 days after GSM–TACE according to the Modified Response Evaluation Criteria in Solid Tumors (mRECIST), and all eight patients showed partial response (PR).

Conclusion

Our results confirmed that GSM–TACE was beneficial for improving anti-tumor immunity in the treatment of HCC.

Programmed cell death protein-1 (PD-1)/programmed death-ligand-1 (PD-L1) axis in hepatocellular carcinoma: prognostic and therapeutic perspectives

Hepatocellular carcinoma (HCC) is the most common primary neoplasia of the liver. There have been tremendous efforts in the development of therapeutic strategies in the last decades. As opposed to other cancer entities immunotherapy has just recently gained popularity in HCC. Among various immunotherapy approaches, programmed cell death protein-1 (PD-1), and its ligand programmed death receptor ligand-1 (PD-L1) axis became one of the most promising pathway of the decade. The scientific interest in PD-1/PD-L1 axis is definitely justified due to: ability to detect PD-L1 expression in patients that underwent resection for HCC with prognostic values; the role of serum PD-L1 as a tool to identify early recurrences and to monitor treatment outcome; PD-1/PDL1 is a highly targetable pathway, with possible predictive markers, and with high clinical applicability that might help us in selecting a subgroup of HCC patients who are most likely to benefit from PD-1/PD-L1 inhibitors. In this review we will first discuss the prognostic role of PD-1/PD-L1 as a bio-marker in various clinical scenarios. Afterwards we will critically analyse the recently published trials with PD-1/PD-L1 inhibitors in HCC either alone or in combination with other treatment modalities. The higher focus will be on clinical rather than preclinical studies. Nevertheless, the strengths and limits of PD-1/PD-L1 axis in both prognosis and therapy of HCC will be highlighted.

Immune response to human telomerase reverse transcriptase-derived helper T cell epitopes in hepatocellular carcinoma patients

BACKGROUND AND AIMS

Human telomerase reverse transcriptase is a catalytic enzyme involved in telomere elongation. It is expressed in many tumours, including hepatocellular carcinoma. The purpose of the present study was to identify major histocompatibility complex class II-restricted helper T cell epitopes derived from human telomerase reverse transcriptase in patients with hepatocellular carcinoma.

METHODS

TEPITOPE software was used to predict helper T cell epitopes based on the entire amino acid sequence of human telomerase reverse transcriptase, and peptides were synthesized based on the predicted sequence. Interferon (IFN)-γ enzyme linked immunospot assay was performed to examine the T cell response to each of the synthesized peptides in peripheral blood mononuclear cells. Furthermore, the peptides were labelled with fluorescein isothiocyanate to test their binding affinity for major histocompatibility complex class II molecules. Lastly, the association between patient characteristics and the level of immune response to these epitopes was examined.

RESULTS

Positive T cell response (>10% enzyme linked immunospot positivity) was detected against 4 of 10 peptides. Among all peptides, positive T cell response to the hTERT₆₈ peptide was detected most frequently. While hTERT₆₈ was HLA-DRB1*0405-restricted, it also bound to other MCH class II molecules. Positive helper T cell response was detected most frequently in hepatocellular carcinoma patients with a low serum alpha-foetoprotein level. Several treatments for hepatocellular carcinoma enhanced the immune response against the peptides.

CONCLUSION

Our findings indicate that helper T cell epitopes identified in the present study may be useful to investigate immune responses and for immunotherapy in hepatocellular carcinoma patients.

Y-90 Radioembolization Combined with a PD-1 Inhibitor for Advanced Hepatocellular Carcinoma

Nivolumab has recently received approval by the Food and Drug Administration for treatment of advanced hepatocellular carcinoma (HCC) in patients previously treated with sorafenib. Nivolumabs' overall response rate of 20% (El-Khoueiry et al. in Lancet 389:2492-2502, 2017) is a step forward for these patients, but there is significant room for improvement. We describe a case of combining Y-90 radioembolization with nivolumab for treatment of angioinvasive HCC, which successfully bridged patient to partial hepatectomy. Surgical pathology showed negative margins with complete pathological response. With the introduction of immunotherapy for HCC, combining Y-90 radioembolization with immunotherapy may enhance the anti-tumoral immune response of checkpoint inhibitors.

Immune checkpoint blockade in advanced hepatocellular carcinoma: an update and critical review of ongoing clinical trials

Systemic treatments for advanced hepatocellular carcinoma (HCC) are evolving rapidly and several multi-targeted tyrosine kinase inhibitors have demonstrated a survival advantage over best supportive care. Despite these treatment advances, the majority of HCC patients will progress on tyrosine kinase inhibitor therapy. Preclinical data indicate that interference with immune checkpoint molecules results in HCC growth suppression. Several clinical trials applying monoclonal antibodies to immune checkpoint molecules have demonstrated durable antitumor activity in advanced HCC patients. As such, pivotal clinical trials are now in progress to assess if these agents will alter the natural history of the disease and further extend the overall survival of advanced HCC patients. This manuscript will review the current status of immune checkpoint blockade in patients with advanced HCC.

Locoregional treatments before liver transplantation for hepatocellular carcinoma: a study from the European Liver Transplant Registry

Locoregional treatment while on the waiting list for liver transplantation (Ltx) for hepatocellular carcinoma (HCC) has been shown to improve survival. However, the effect of treatment type has not been investigated. We investigate the effect of locoregional treatment type on survival after Ltx for HCC. We investigated patients registered in the European Liver Transplant Registry database using multivariate Cox regression survival analysis. Information on locoregional therapy was registered for 4978 of 23 124 patients and was associated with improved overall survival [hazard ratio (HR) 0.84 (0.73-0.96)] and HCC-specific survival [HR 0.76 (0.59-0.98)]. Radiofrequency ablation (RFA) was the one monotherapy associated with improved overall survival [HR 0.51 (0.40-0.65)]. In addition, the combination of RFA and transarterial chemoembolization also improved survival [HR 0.74 (0.55-0.99)]. Adjusting for factors related to prognosis, disease severity, and tumor aggressiveness, RFA was highly beneficial for overall and HCC-specific survival. The effect may represent a selection of patients with favorable tumor biology; however, the treatment may be effective per se by halting tumor progression. Clinicaltrials.gov number: NCT02995096.

Immunomodulation in hepatocellular cancer

Hepatocellular carcinoma (HCC) is the fastest growing malignancy in the United States in relation to mortality. HCC relies on a complex immunosuppressive network to modify the host immune system and evade destruction. Intrinsic to the liver's function and anatomy, native hepatic and immune cells produce many inhibitory cytokines that promote tolerogenicity and limit immune response. Since the introduction of sorafenib in 2008, no treatment has been able to demonstrate improved survival in patients with advanced HCC post disease progression treated with sorafenib. More recent studies have shown that sorafenib has an immunomodulatory function in addition to inhibition of multiple tyrosine kinases. Clinical trials have aimed to further enhance this immunomodulatory function with other treatments, most promisingly immune checkpoint inhibitors. Additionally, ongoing studies are using combinatorial approaches with immunomodulatory treatment and liver directed therapies such as transarterial chemoembolization (TACE), radiofrequency ablation (RFA), microwave ablation (MWA), and cryoablation. This article will review recent data describing the immunosuppressive network in HCC, recent results of immunotherapies, and combinatorial approaches to treat advanced HCC.

Ex Vivo PD-L1/PD-1 Pathway Blockade Reverses Dysfunction of Circulating CEA-Specific T Cells in Pancreatic Cancer Patients

Purpose: Carcinoembryonic antigen (CEA) is a candidate target for cellular immunotherapy of pancreatic cancer. In this study, we have characterized the antigen-specific function of autologous cytotoxic T lymphocytes (CTL) specific for the HLA-A2-restricted peptide, pCEA691-699, isolated from the peripheral T-cell repertoire of pancreatic cancer patients and sought to determine if ex vivo PD-L1 and TIM-3 blockade could enhance CTL function.Experimental Design: CD8⁺ T-cell lines were generated from peripheral blood mononuclear cells of 18 HLA-A2⁺ patients with pancreatic cancer and from 15 healthy controls. In vitro peptide-specific responses were evaluated by flow cytometry after staining for intracellular cytokine production and carboxy fluorescein succinimydyl ester cytotoxicity assays using pancreatic cancer cell lines as targets.Results: Cytokine-secreting functional CEA691-specific CTL lines were successfully generated from 10 of 18 pancreatic cancer patients, with two CTL lines able to recognize and kill both CEA691 peptide-loaded T2 cells and CEA⁺ HLA-A2⁺ pancreatic cancer cell lines. In the presence of ex vivo PD-L1 blockade, functional CEA691-specific CD8⁺ T-cell responses, including IFNγ secretion and proliferation, were enhanced, and this effect was more pronounced on Ag-specific T cells isolated from tumor draining lymph nodes.Conclusions: These data demonstrate that CEA691-specific CTL can be readily expanded from the self-restricted T-cell repertoire of pancreatic cancer patients and that their function can be enhanced by PD-L1 blockade. Clin Cancer Res; 23(20); 6178-89. ©2017 AACR.

Immuno-oncology and Its Opportunities for Interventional Radiologists: Immune Checkpoint Inhibition and Potential Synergies with Interventional Oncology Procedures

Immunotherapy, specifically the use of immune checkpoint inhibitors, offers a new approach to fighting cancer. Although the results of treatment with immune checkpoint inhibition alone have been remarkable for certain cancers, these results are not universal. Preclinical and early clinical studies indicate the potential for synergistic effects when immune checkpoint inhibition is combined with immunogenic local therapies such as ablation and embolization. This review offers an overview of immunology as it relates to immune checkpoint inhibition and the possibilities for synergy when combined with interventional radiology treatments.

A Phase I trial using local regional treatment, nonlethal irradiation, intratumoral and systemic polyinosinic-polycytidylic acid polylysine carboxymethylcellulose to treat liver cancer: in search of the abscopal effect

Purpose

To determine the safety of an approach to immunologically enhance local treatment of hepatocellular cancer (HCC) by combining nonlethal radiation, local regional therapy with intratumoral injection, and systemic administration of a potent Toll-like receptor (TLR) immune adjuvant.

Methods

Patients with HCC not eligible for liver transplant or surgery were subject to: 1) 3 fractions of 2-Gy focal nonlethal radiation to increase tumor antigen expression, 2) intra-/peri-tumoral (IT) injection of the TLR3 agonist, polyinosinic-polycytidylic acid polylysine carboxymethylcellulose (poly-ICLC), to induce an immunologic “danger” response in the tumor microenvironment with local regional therapy, and 3) systemic boosting of immunity with intramuscular poly-ICLC. Primary end points were safety and tolerability; secondary end points were progression-free survival (PFS) and overall survival (OS) at 6 months, 1 year, and 2 years.

Results

Eighteen patients with HCC not eligible for surgery or liver transplant were treated. Aside from 1 embolization-related severe adverse event, all events were ≤grade II. PFS was 66% at 6 months, 39% at 12 months, and 28% at 24 months. Overall 1-year survival was 69%, and 2-year survival 38%. In patients <60 years old, 2-year survival was 62.5% vs. 11.1% in patients aged >60 years (P<0.05). Several patients had prolonged PFS and OS.

Conclusion

Intra-tumoral injection of the TLR3 agonist poly-ICLC in patients with HCC is safe and tolerable when combined with local nonlethal radiation and local regional treatment. Further work is in progress to evaluate if this approach improves survival compared to local regional treatment alone and characterize changes in anticancer immunity.

Advanced Hepatocellular Cancer: the Current State of Future Research

OPINION STATEMENT

Hepatocellular carcinoma is a common malignancy worldwide, rapidly rising in incidence. While there have been some developments in advancing therapeutic options in this disease, these have admittedly been modest to date, and as a result, this is a patient population with an inherently poor prognosis. Currently, sorafenib remains the only established systemic therapy proven to increase the overall survival of patients with advanced disease. The approval of sorafenib in 2007 ushered in the era of targeted therapies. Several phase 2 and 3 clinical trials have failed however to improve on sorafenib in the first-line setting, and no single agent has been demonstrated to impact outcomes after sorafenib failure. Having reached somewhat of an impasse in terms of drug development in hepatocellular carcinoma, enthusiasm in the field has moved toward innovative approaches such as molecular characterization and immunotherapy in an attempt to impact survival. This review highlights the current endeavors in terms of experimental research for patients with advanced hepatocellular carcinoma.

Adjuvant Medications That Improve Survival after Locoregional Therapy

PURPOSE

To determine if outpatient medications taken at the time of liver tumor embolization or ablation affect survival.

MATERIALS AND METHODS

A retrospective review was done of 2,032 liver tumor embolization, radioembolization, and ablation procedures performed in 1,092 patients from June 2009 to April 2016. Pathology, hepatocellular carcinoma (HCC) stage (American Joint Committee on Cancer), neuroendocrine tumor (NET) grade, initial locoregional therapy, overall survival after initial locoregional therapy, Child-Pugh score, Eastern Cooperative Oncology Group performance status, Charlson Comorbidity Index, and outpatient medications taken at the time of locoregional therapy were analyzed for each patient. Kaplan-Meier survival curves were calculated for patients taking 29 medications or medication classes (including prescription and nonprescription medications) for reasons unrelated to their primary cancer diagnosis. Kaplan-Meier curves were compared using the log-rank test.

RESULTS

For patients with HCC initially treated with embolization (n = 304 patients), the following medications were associated with improved survival when taken at the time of embolization: beta-blockers (P = .0007), aspirin (P = .0008) and other nonsteroidal antiinflammatory drugs (P = .009), proton pump inhibitors (P = .004), and antivirals for hepatitis B or C (P = .01). For colorectal liver metastases initially treated with ablation (n = 172 patients), beta-blockers were associated with improved survival when taken at the time of ablation (P = .02).

CONCLUSIONS

Aspirin and beta-blockers are associated with significantly improved survival when taken at the time of embolization for HCC. Aspirin was not associated with survival differences after locoregional therapy for NET or colorectal liver metastases, suggesting an HCC-specific effect.

Tremelimumab in combination with ablation in patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS

Tremelimumab is a fully human monoclonal antibody that binds to cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) on the surface of activated T lymphocytes. Ablative therapies induce a peripheral immune response which may enhance the effect of anti-CTLA4 treatment in patients with advanced hepatocellular carcinoma (HCC). This study aimed to demonstrate whether tremelimumab could be combined safely and feasibly with ablation.

METHODS

Thirty-two patients with HCC were enrolled: male:female: 28:4; median age: 62 (range 36-76). Patients were given tremelimumab at two dose levels (3.5 and 10mg/kg i.v.) every 4weeks for 6 doses, followed by 3-monthly infusions until off-treatment criteria were met. On day 36, patients underwent subtotal radiofrequency ablation or chemoablation. Staging was performed by contrast-enhanced CT or MRI scan every 8weeks.

RESULTS

No dose-limiting toxicities were encountered. The most common toxicity was pruritus. Of the 19 evaluable patients, five (26.3%; 95% CI: 9.1-51.2%) achieved a confirmed partial response. Twelve of 14 patients with quantifiable HCV experienced a marked reduction in viral load. Six-week tumor biopsies showed a clear increase in CD8⁺ T cells in patients showing a clinical benefit only. Six and 12-month probabilities of tumor progression free survival for this refractory HCC population were 57.1% and 33.1% respectively, with median time to tumor progression of 7.4months (95% CI 4.7 to 19.4months). Median overall survival was 12.3months (95% CI 9.3 to 15.4months).

CONCLUSIONS

Tremelimumab in combination with tumor ablation is a potential new treatment for patients with advanced HCC, and leads to the accumulation of intratumoral CD8⁺ T cells. Positive clinical activity was seen, with a possible surrogate reduction in HCV viral load.

LAY SUMMARY

Studies have shown that the killing of tumors by direct methods (known as ablation) can result in the immune system being activated or switched on. The immune system could potentially also recognize and kill the cancer that is left behind. There are new drugs available known as immune checkpoint inhibitors which could enhance this effect. Here, we test one of these drugs (tremelimumab) together with ablation.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov: NCT01853618.

Myeloid-derived suppressor cells correlate with patient outcomes in hepatic arterial infusion chemotherapy for hepatocellular carcinoma

Hepatic arterial infusion chemotherapy (HAIC) has been employed as an alternative therapy to sorafenib for the patients with advanced hepatocellular carcinoma (HCC). In this study, we performed a comparative analysis of various immune cell responses including tumor-associated antigen (TAA)-specific T cells, regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) in advanced HCC patients treated with HAIC. Thirty-six HCC patients were examined in the study. Interferon gamma enzyme-linked immunospot assays were performed to examine the frequency of TAA-specific T cells. The frequencies of Tregs and MDSCs were examined by multicolor fluorescence-activated cell sorting analysis. The treatment with HAIC using interferon (IFN)/5-fluorouracil (FU) or IFN/FU + cisplatin modulated the frequencies of various immune cells. In 22.2 % of patients, the frequency of TAA-specific T cells increased after HAIC. Although the frequency of Tregs decreased after HAIC, it was not associated with the prognosis of patients. An analysis of prognostic factors for overall survival identified diameter of the tumor (<3.0 cm), absence of major portal vein invasion, absence of distant metastasis, Union Internationale Contre Le Cancer tumor lymph node metastasis stage (I or II), neutrophil lymphocytic ratio (<2.1) and the frequency of MDSCs (<30.5 %) as factors that prolonged overall survival time after HAIC. Even in the group adjusted with progressive levels of tumors, patients with a low frequency of MDSCs had a significantly longer overall survival time. In conclusion, the frequency of MDSCs before the treatment is a prognostic factor in HAIC against HCC.

Immunotherapy in hepatocellular carcinoma: Primed to make a difference?

Advanced hepatocellular carcinoma (HCC) carries a dismal prognosis and the current treatment is limited to sorafenib, an agent with modest benefit. Preclinical data have indicated that several immunologic mechanisms are at play to promote HCC development and growth while impairing effective antitumor immune surveillance. Several novel approaches geared toward manipulating the immune response to HCC have suggested a therapeutic benefit in early-stage clinical trials, indicating a real potential to augment tumor-specific immunity and improve outcomes in patients with this disease. In the current study, the authors reviewed the barriers to an effective immune response against HCC and contemporary clinical investigations that may be "primed" to alter the natural history of HCC.

Cancer vaccines

Cancer vaccines are designed to promote tumor specific immune responses, particularly cytotoxic CD8 positive T cells that are specific to tumor antigens. The earliest vaccines, which were developed in 1994-95, tested non-mutated, shared tumor associated antigens that had been shown to be immunogenic and capable of inducing clinical responses in a minority of people with late stage cancer. Technological developments in the past few years have enabled the investigation of vaccines that target mutated antigens that are patient specific. Several platforms for cancer vaccination are being tested, including peptides, proteins, antigen presenting cells, tumor cells, and viral vectors. Standard of care treatments, such as surgery and ablation, chemotherapy, and radiotherapy, can also induce antitumor immunity, thereby having cancer vaccine effects. The monitoring of patients' immune responses at baseline and after standard of care treatment is shedding light on immune biomarkers. Combination therapies are being tested in clinical trials and are likely to be the best approach to improving patient outcomes.

Aspartate-β-hydroxylase induces epitope-specific T cell responses in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a poor prognosis due to high recurrence rate. Aspartate-β-hydroxylase (ASPH) is a highly conserved transmembrane protein, which is over expressed in HCC and promotes a malignant phenotype. The capability of ASPH protein-derived HLA class I and II peptides to generate antigen specific CD4(+) and CD8(+) immune responses is unknown. Therefore, these studies aim to define the epitope specific components required for a peptide based candidate vaccine. Monocyte-derived dendritic cells (DCs) generated from the peripheral blood mononuclear cells (PBMCs) of HCC patients were loaded with ASPH protein. Helper CD4(+) T cells and CD8(+) cytotoxic T lymphocytes (CTLs) were co-incubated with the DCs; T cell activation was evaluated by flow cytometric analysis. Immunoinformatics tools were used to predict HLA class I- and class II-restricted ASPH sequences, and the corresponding peptides were synthesized. The immunogenicity of each peptide in cultures of human PBMCs was determined by IFN-γ ELISpot assay. ASPH protein-loaded DCs activated both CD4(+) and CD8(+) T cells contained within the PBMC population derived from HCC patients. Furthermore, the predicted HLA class I- and class II-restricted ASPH peptides were significantly immunogenic. Both HLA class I- and class II-restricted peptides derived from ASPH induce T cell activation in HCC. We observed that ASPH protein and related peptides were highly immunogenic in patients with HCC and produce the type of cellular immune responses required for generation of anti-tumor activity.

Dynamic changes of the inflammation-based index predict mortality following chemoembolisation for hepatocellular carcinoma: a prospective study

BACKGROUND

Transarterial chemoembolisation (TACE) is a standard treatment for unresectable, intermediate stage hepatocellular carcinoma (HCC). Survival after TACE, however, can be highly variable, with no suitable biomarker predicting therapeutic outcome. The inflammation-based index (IBI) has previously been shown to independently predict overall survival (OS) in all stages of HCC.

AIM

To explore the prognostic ability of IBI as a predictor of survival after TACE.

METHODS

Baseline staging, biochemical and clinicopathological features including IBI were studied in a derivation set of 64 patients undergoing TACE for intermediate stage HCC. Dynamic changes in IBI before and after TACE were studied as predictors of survival using both a univariate and multivariate Cox regression model and further validated in two independent patient cohorts from Korea (n = 76) and Japan (n = 577).

RESULTS

Pre-treatment IBI predicted for OS in the derivation set (P = 0.001). Other univariate predictors of OS included radiological response to TACE (P < 0.001), pre-TACE CLIP score (P < 0.01), tumour diameter >5 cm (P = 0.05) and AFP ≥400 (P < 0.001). Normalisation of IBI post-TACE was associated with radiological response by mRECIST criteria and improved OS (P < 0.001). Normalisation of IBI remained a significant multivariate predictor of OS in both the derivation and validation sets (P < 0.001).

CONCLUSIONS

Normalisation of IBI after TACE is shown to be an independent predictor of survival and may be integrated into the retreatment criteria for repeat TACE in intermediate stage HCC. IBI and its dynamic changes after treatment are validated as a biomarker allowing the stratification of patients with a significant survival advantage following initial TACE.

Spontaneous and therapeutic immune responses in hepatocellular carcinoma: implications for current and future immunotherapies

Hepatocellular carcinoma (HCC) represents a major health problem in the world, ranking fifth in incidence and third in cancer-related deaths. Due to the unique immunosuppressive microenvironment of the liver, HCC develops in an immunotolerant niche posing an important obstacle to immunotherapy. A number of studies, however, have shown immunogenic properties of HCC by demonstrating spontaneous adaptive immune responses during tumor formation and progression. Furthermore, studies examining immune responses during HCC therapy have revealed that conventional treatments such as surgical resection, locoregional therapy and systemic therapy with antibodies, small molecules or chemotherapy induce adaptive immune responses that contribute to therapeutic effects. These observations have provided a basis for clinical trials involving adoptive transfers of T cells or natural killer cells, peptide and dendritic cell vaccinations or, more recently, virotherapy and inhibition of co-inhibitory molecules. Here, spontaneous and therapeutic immune responses in HCC and their implication for current and future immunotherapies are discussed.

Hepatocellular carcinoma from an immunologic perspective

Hepatocellular carcinoma is the third most common cancer worldwide. It is an inflammation-associated cancer. Multiple investigators have demonstrated that analysis of the tumor microenvironment may be used to predict patient outcome, indicating the importance of local immune responses in this disease. In contrast with other types of cancer, in which surgery, radiation, and systemic cytotoxic chemotherapies dominate the treatment options, in hepatocellular carcinoma locoregional treatments are widely applied. Such treatments induce rapid tumor cell death and antitumor immune responses, which may favor or impair the patients' outcome. Recent immunotherapeutic studies demonstrating promising results include trials evaluating intratumoral injection of an oncolytic virus expressing granulocyte macrophage colony-stimulating factor, glypican-3 targeting treatments, and anti-CTLA4 treatment. Although some of these novel approaches may provide benefit as single agents, there is a clear opportunity in hepatocellular carcinoma to evaluate these in combination with the standard modalities to more effectively harness the immune response.

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.

Tim-3/galectin-9 signaling pathway mediates T-cell dysfunction and predicts poor prognosis in patients with hepatitis B virus-associated hepatocellular carcinoma

The interaction between T cell immunoglobulin- and mucin-domain-containing molecule (Tim-3) expressed on T helper 1 (Th1) cells, and its ligand, galectin-9, negatively regulates Th1-mediated immune responses. However, it is poorly understood if and how the Tim-3/galectin-9 signaling pathway is involved in immune escape in patients with hepatocellular carcinoma (HCC). Here we studied the expression, function, and regulation of the Tim-3/galectin-9 pathway in patients with hepatitis B virus (HBV)-associated HCC. We detected different levels of galectin-9 expression on antigen-presenting cell (APC) subsets including Kupffer cells (KCs), myeloid dendritic cells (DCs), and plasmacytoid DCs in HCC. The highest galectin-9 expression was on KCs in HCC islets, not in the adjacent tissues. Furthermore, Tim-3 expression was increased on CD4(+) and CD8(+) T cells in HCC as compared to the adjacent tissues, and Tim-3(+) T cells were replicative senescent and expressed surface and genetic markers for senescence. Interestingly, tumor-infiltrating T-cell-derived interferon (IFN)-γ stimulated the expression of galectin-9 on APCs in the HCC microenvironment. Immunofluorescence staining revealed a colocalization of Tim-3(+) T cells and galectin-9(+) KCs in HCC. Functional studies demonstrated that blockade of the Tim-3/galectin-9 signaling pathway importantly increased the functionality of tumor-infiltrating Tim-3(+) T cells as shown by increased T-cell proliferation and effector cytokine production. Finally, we show that the numbers of Tim-3(+) tumor-infiltrating cells were negatively associated with patient survival.

CONCLUSION

Our work demonstrates that the Tim-3/galectin-9 signaling pathway mediates T-cell senescence in HBV-associated HCC. The data suggest that this pathway could be an immunotherapeutic target in patients with HBV-associated HCC.

Comparative analysis of various tumor-associated antigen-specific t-cell responses in patients with hepatocellular carcinoma

Many tumor-associated antigens (TAAs) recognized by cytotoxic T cells (CTLs) have been identified during the last two decades and some of them have been used in clinical trials. However, there are very few in the field of immunotherapy for hepatocellular carcinoma (HCC) because there have not been comparative data regarding CTL responses to various TAAs. In the present study, using 27 peptides derived from 14 different TAAs, we performed comparative analysis of various TAA-specific T-cell responses in 31 HCC patients to select useful antigens for immunotherapy and examined the factors that affect the immune responses to determine a strategy for more effective therapy. Twenty-four of 31 (77.4%) HCC patients showed positive responses to at least one TAA-derived peptide in enzyme-linked immunospot assay. The TAAs consisting of cyclophilin B, squamous cell carcinoma antigen recognized by T cells (SART) 2, SART3, p53, multidrug resistance-associated protein (MRP) 3, alpha-fetoprotein (AFP) and human telomerase reverse transcriptase (hTERT) were frequently recognized by T cells and these TAA-derived peptides were capable of generating peptide-specific CTLs in HCC patients, which suggested that these TAAs are immunogenic. HCC treatments enhanced TAA-specific immune responses with an increased number of memory T cells and induced de novo T-cell responses to lymphocyte-specific protein tyrosine kinase, human epidermal growth factor receptor type 2, p53, and hTERT. Blocking cytotoxic T-lymphocyte antigen-4 (CTLA-4) resulted in unmasking of TAA-specific immune responses by changing cytokine and chemokine profiles of peripheral blood mononuclear cells stimulated by TAA-derived peptides.

CONCLUSION

Cyclophilin B, SART2, SART3, p53, MRP3, AFP, and hTERT were immunogenic targets for HCC immunotherapy. TAA-specific immunotherapy combined with HCC treatments and anti-CTLA-4 antibody has the possibility to produce stronger tumor-specific immune responses.

Lack of ex vivo peripheral and intrahepatic α-fetoprotein-specific CD4+ responses in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies with a poor prognosis and limited therapeutic options that is often characterized by the expression of the tumor-associated antigen α-fetoprotein (AFP). CD4+ helper T cells are important in generating potent anticancer immunity as they prime and expand CD8+ T-cell memory and may also have direct antitumor activity. However, very little information is currently available about the relative frequency, immunodominance and peripheral versus intratumoral distribution of AFP-specific CD4+ T-cell responses in patients with HCC. We, therefore, analyzed AFP-specific CD4+ responses in blood and tumor tissue of patients with HCC by using overlapping peptides spanning the entire AFP protein and novel sensitive approaches such as antigen-specific upregulation of CD154. We found that AFP-specific CD4+ T-cell responses were not detectable in the peripheral blood ex vivo. However, after in vitro stimulation, AFP-specific CD4+ T-cell responses were detectable in a large fraction of patients targeting different previously unreported epitopes with no clear immunodominance. These results indicate that AFP-specific CD4+ T-cell responses are not completely deleted but only present at very low frequencies. Importantly, AFP-specific CD4+ T-cell responses were also rarely detectable in tumor tissue, suggesting that the relative absence of these cells in the circulation ex vivo is not due to a rapid accumulation to the tumor side. Taken together, these results suggest that the lack of sufficient CD4+ T-cell help, especially within the tumor tissue, may be one central mechanism responsible for the failure of AFP-specific immune responses to control HCC progression.

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.

Alpha-fetoprotein specific CD4 and CD8 T cell responses in patients with hepatocellular carcinoma

The presence of CD8 T cell responses to tumor associated antigens have been reported in patients with different malignancies. However, there is very little information on a comparable CD8 and CD4 T cell response to a tumor antigen in liver cancer patients. Here, we re-examine the kinetic and the pattern of T helper 1 and cytotoxic T lymphocyte responses to alpha-fetoprotein (AFP), a tumor rejection antigen in hepatocellular carcinoma (HCC). Then, we discuss the possibility of using AFP-based immunotherapy in combination with necrotizing treatments in HCC patients.

Low-dose cyclophosphamide treatment impairs regulatory T cells and unmasks AFP-specific CD4+ T-cell responses in patients with advanced HCC

Immunotherapy represents a potential therapeutic option for patients with hepatocellular carcinoma (HCC). However, CD4CD25Foxp regulatory T cells, which suppress potential antigen-specific T-cell responses, are increased in patients with HCC and might impair the effect of an immune-based therapeutic approach. In this study, we demonstrate that depletion of regulatory T cells in vitro unmasks alpha-fetoprotein-specific T-cell responses in HCC patients. On the basis of these results, we performed a clinical trial, in which 13 patients with advanced HCC ineligible for any other type of treatment were treated with 150, 250, or 350 mg/m cyclophosphamide on day 1 and 29 to suppress regulatory T cells in these patients (NCT00396682). The primary end point of this trial was regulatory T-cell number and function. Low-dose cyclophosphamide treatment (150 and 250 mg/m) induced a decrease in the absolute and relative frequency of CD4CD25Foxp regulatory T cells in peripheral blood on days 8 and 29. Suppressor function of regulatory T cells was impaired after treatment of patients with 250 mg/m on days 8 and 21. Finally, alpha-fetoprotein-specific T-cell responses were unmasked in 6/13 treated patients. In summary, systemic treatment of HCC patients with low-dose cyclophosphamide decreases the frequency and suppressor function of circulating CD4CD25Foxp regulatory T cells in peripheral blood and could be used in combination with immunotherapeutic approaches in HCC.

Immunotherapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents the third most common cause of cancer-related death worldwide and efficient treatment options are urgently needed. Based on its pathogenesis, in addition to a number of correlative studies, immunotherapy represents a potential therapeutic option for patients with HCC. However, tumors have also evolved numerous immune escape mechanisms, including the generation of cells with immune suppressor functions, such as Tregs and myeloid-derived suppressor cells. It has been shown that these suppressor cells mask tumor-specific immune responses in patients with HCC. Different immunotherapeutic approaches including peptide- and dendritic cell-based therapies have demonstrated promising results in patients with HCC. However, we propose that any of these immunotherapeutic approaches needs to be combined with a therapy specifically targeting suppressor cells in HCC.