Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Antitumor immunostimulatory activity of polysaccharides from Salvia chinensis Benth

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia chinensis Benth (S. chinensis) is a traditional herb applied in the treatment of hepatocellular carcinoma (HCC). Polysaccharides abundantly exist in this plant. However, it remains poorly understood if polysaccharides from S. chinensis (PSSC) contribute to its anti-HCC activity.

MATERIALS AND METHODS

The in vivo anti-HCC activity of PSSC was evaluated in Kunming mice bearing H22 ascitic hepatoma cells. An array of physiological indexes was measured to evaluate toxicological effects on host animals. Subgroups of immune cells were purified by a magnetic-activated cell sorting system and analyzed by flow cytometry. Reverse transcription real-time PCR and immunoblotting were recruited to determine the effects of PSSC on the cellular signaling of different subgroup of immune cells.

RESULTS

PSSC suppressed in vivo proliferation of H22 cells with undetectable toxic effects on tumor-bearing mice. PSSC alleviated tumor transplantation-induced CD4+ T cell apoptosis and dysregulation of serum cytokine profiles, which elevated cytotoxic activities of natural killer and CD8+ T cells. PSSC reduced serum levels of prostaglandin E2 (PGE2). Injection of exogenous PGE2 completely abrogated the antitumor immunostimulatory activity of PSSC. Cyclic adenosine monophosphate (cAMP) is the second messager of PGE2. In CD4+ T cells, PSSC substantially declined intracellular cAMP. This event elevated protein levels of JAK3, enhancing STAT5 phosphorylation and STAT5-dependent expression of anti-apoptotic genes. Cyclooxygenase-2 is the key enzyme mediating biosynthesis of PGE2. PSSC suppressed the transcription and translation of cyclooxygenase-2 in tumor associated macrophages.

CONCLUSION

Our data clearly showed antitumor immunostimulatory activity of PSSC against transplanted H22 HCC cells. Suppressing tumor transplantation-induced PGE2 production was implicated in the anti-tumor immunostimulatory activity of PSSC. These works provides novel insights into the traditional application of S. chinensis against HCC and supported considering PSSC as an adjuvant reagent in clinical HCC treatment.

GITR engagement in combination with CTLA-4 blockade completely abrogates immunosuppression mediated by human liver tumor-derived regulatory T cells ex vivo

In liver cancer tumor-infiltrating regulatory T cells (Ti-Treg) are potent suppressors of tumor-specific T-cell responses and express high levels of the Treg-associated molecules cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor receptor (GITR). In this study, we have evaluated the capacity of GITR-ligation, CTLA-4-blockade and a combination of both treatments to alleviate immunosuppression mediated by Ti-Treg. Using ex vivo isolated cells from individuals with hepatocellular carcinoma (HCC) or liver metastases from colorectal cancer (LM-CRC) we show that treatment with a soluble form of the natural ligand of GITR (GITRL), or with blocking antibodies to CTLA-4, reduces the suppression mediated by human liver tumor-infiltrating CD4⁺Foxp3+ Treg, thereby restoring proliferation and cytokine production by effector T cells. Importantly, combined treatment with low doses of both molecules exhibited stronger recovery of T cell function compared with either treatment alone. Our data suggest that in patients with primary and secondary liver cancer both GITR-ligation and anti-CTLA-4 mAb can improve the antitumor immunity by abrogating Ti-Treg mediated suppression.

Engineering α-fetoprotein-based gene vaccines to prevent and treat hepatocellular carcinoma: review and future prospects

Activation of a patient's immune system offers an attractive approach to prevent and treat hepatocellular carcinoma (HCC). However, the antitumor efficacy of current HCC vaccines was weak owing to insufficient immune activation of targeting self/tumor antigens. We recently found that epitope-optimized α-fetoprotein effectively activated CD8 T cells and generated potent antitumor effects in the carcinogen-induced autochthonous HCC mouse model. We predict that the same antigen engineering approach of epitope-optimization will enable us to develop effective human vaccines to prevent HCC recurrence after liver resection. The engineered human HCC vaccines may also allow us to identify high-affinity T-cell receptors and antibodies that can be used to reprogram T cells to treat HCC tumors via adoptive transfer.

The immune system in hepatocellular carcinoma and potential new immunotherapeutic strategies

BACKGROUND

Hepatocellular carcinoma is a major health problem worldwide and the third most common cause of cancer-related death. HCC treatment decisions are complex and dependent upon tumor staging. Several molecular targeted agents have been evaluated in clinical trials in advanced HCC. Despite of only modest objective response rates according to the Response Evaluation Criteria in Solid Tumors, several studies showed encouraging results in terms of prolongation of the time to progression, disease stabilization, and survival. Cellular immunotherapy would improve the immune state and has potential in enhancing the therapeutic outcome for HCC patients.

MATERIALS AND METHODS

A search of the literature was made using cancer literature, the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: "hepatocellular carcinoma," "molecular hepatocarcinogenesis," "targeted therapy," "molecular immunological targets," "tumour-associated antigens," "Tregs," "MDSCs," "immunotherapy."

DISCUSSION AND CONCLUSION

Treatment strategies combining blockade of immunoregulatory cell types such as Tregs and MDSCs and of inhibitory receptors, with vaccine-induced activation of TAA-specific T cells, may be necessary to achieve the most effective therapeutic antitumour activity in HCC. In the future, new therapeutic options will be represented by a blend of immunotherapy-like vaccines and T-cell modulators, supplemented by molecularly targeted inhibitors of tumor signaling pathways.

Tumor-infiltrating plasmacytoid dendritic cells promote immunosuppression by Tr1 cells in human liver tumors

CD4⁺ type 1 T regulatory (Tr1) cells have a crucial role in inducing tolerance. Immune regulation by these cells is mainly mediated through the secretion of high amounts of IL-10. Several studies have suggested that this regulatory population may be involved in tumor-mediated immune-suppression. However, direct evidence of a role for Tr1 cells in human solid tumors is lacking. Using ex vivo isolated cells from individuals with hepatocellular carcinoma (HCC; n = 39) or liver metastases from colorectal cancer (LM-CRC; n = 60) we identify a CD4⁺FoxP3^-IL-13^-IL-10⁺ T cell population in tumors of individuals with primary or secondary liver cancer that is characterized as Tr1 cells by the expression of CD49b and the lymphocyte activation gene 3 (LAG-3) and strong suppression activity of T cell responses in an IL-10 dependent manner. Importantly, the presence of tumor-infiltrating Tr1 cells is correlated with tumor infiltration of plasmacytoid dendritic cells (pDCs). pDCs exposed to tumor-derived factors enhance IL-10 production by Tr1 cells through up-regulation of the inducible co-stimulatory ligand (ICOS-L). These findings suggest a role for pDCs and ICOS-L in promoting intra-tumoral immunosuppression by Tr1 cells in human liver cancer, which may foster tumor progression and which might interfere with attempts of immunotherapeutic intervention.

Hepatocellular carcinoma tumor board: making sense of the technologies

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death, with a rising global incidence. The vast majority of HCC cases occur in the setting of liver cirrhosis, mainly due to chronic hepatitis C (HCV) or hepatitis B (HBV) viral infections, alcohol consumption, and nonalcoholic fatty liver disease. The new approval of curative therapy with two NS5A inhibitors, ledipasvir and sofosbuvir, for the treatment of HCV will no doubt affect HCC incidence and outcome. No studies have evaluated the use of the new antivirals in patients with HCC. Staging and scoring remain an integral part of the management of patients with advanced HCC. Curative therapies for the treatment of HCC are evolving. Improvements in surgical techniques and risk stratification for orthotopic liver transplantation (OLT) have expanded access and improved the outlook for patients suffering from HCC. Interventional locoregional treatments continue to play a key role in the management of HCC. Transarterial chemoembolization is considered the standard of care for patients with noninvasive multinodular tumors at the intermediate stage. Bland embolization appears to have similar virtues in some studies. Y90 radioembolization represents a promising treatment option for patients unfit or refractory to transarterial chemoembolization. The advent of sorafenib as a standard of care with an improvement in survival sadly remain the only major breakthrough in the treatment of advanced HCC, with mounting negative data from multiple clinical trials. Advances in immunotherapy and customized therapy may hopefully help reverse this tide.

Tumor-derived α-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells

Several tumor-derived factors have been implicated in dendritic cell (DC) dysfunction in cancer patients. α-fetoprotein (AFP) is an oncofetal Ag that is highly expressed in abnormalities of prenatal development and several epithelial cancers, including hepatocellular carcinoma (HCC). In HCC patients exhibiting high levels of serum AFP, we observed a lower ratio of myeloid/plasmacytoid circulating DCs compared with patients with low serum AFP levels and healthy donors. To test the effect of AFP on DC differentiation in vitro, peripheral blood monocytes from healthy donors were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP), and DC phenotype and function were assessed. Although the nAFP and tAFP isoforms only differ at one carbohydrate group, low (physiological) levels of tAFP, but not nAFP, significantly inhibited DC differentiation. tAFP-conditioned DCs expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, exhibited limited production of inflammatory mediators, and failed to induce robust T cell proliferative responses. Mechanistic studies revealed that the suppressive activity of tAFP is dependent on the presence of low molecular mass (LMM) species that copurify with tAFP and function equivalently to the LMM fractions of both tumor and nontumor cell lysates. These data reveal the unique ability of tAFP to serve as a chaperone protein for LMM molecules, both endogenous and ubiquitous in nature, which function cooperatively to impair DC differentiation and function. Therefore, novel therapeutic approaches that antagonize the regulatory properties of tAFP will be critical to enhance immunity and improve clinical outcomes.

T-cell suppression mediated by regulatory T cells infiltrating hepatic tumors can be overcome by GITRL treatment

Recently, we reported the accumulation of CD4⁺FOXP3⁺ regulatory T cells (Tregs) within the tumor mass of patients bearing liver cancer. Tumor-infiltrating Tregs (TiTregs) are active and potent suppressors of antitumor immunity. Importantly, treatment with GITRL reduced the immunosuppression mediated by TiTregs.

Prognostic value of preoperative absolute lymphocyte count in recurrent hepatocellular carcinoma following thermal ablation: a retrospective analysis

Purpose

To investigate the prognostic value of preoperative absolute lymphocyte count (ALC) in recurrent hepatocellular carcinoma (RHCC) following thermal ablation.

Materials and methods

We retrospectively analyzed the relationship between preoperative ALC and the clinicopathologic factors and long-term prognosis in 423 RHCC patients who underwent curative thermal ablation. Correlation analysis, receiver operating characteristic (ROC) calculation, Kaplan–Meier curves, and multivariate regression were used for statistical analysis.

Results

The median time to recurrence was 12 months for RHCC patients after thermal ablation. On multivariate Cox regression analysis, preoperative ALC was an independent risk factor for cancer recurrence, along with tumor differentiation and α-fetoprotein level. ALC ≥1.64×10⁹/L defined by ROC calculation was associated with prolonged survival (area under the curve 0.741, P<0.001). Patients with ALC ≥1.64×10⁹/L showed a mean survival of 20.2 months versus 11.6 months for patients with ALC <1.64×10⁹/L (P<0.001). Patients were stratified into high and low groups according to ALC status. After excluding the basic parameters between groups, the 1- and 3-year recurrence rates in the high group were 20.9% and 29.5%, respectively, which were significantly lower than those of the low group (58.4% and 71.9%, respectively; P<0.001). The recurrence-free survival rates in the two groups analyzed by Kaplan–Meier curves were significantly different (P<0.001).

Conclusion

Preoperative ALC is a powerful prognostic factor for RHCC recurrence after thermal ablation, which suggests that maintaining a high ALC in RHCC patients might improve cancer outcomes.

Kanglaite stimulates anticancer immune responses and inhibits HepG2 cell transplantation‑induced tumor growth

Previous studies revealed that Kanglaite (KLT) exhibits antitumor and immunomodulatory activities. In the present study, we show that KLT treatment stimulated the immune response by increasing the number of T cells and natural killer (NK) cells in the blood of hepatocellular carcinoma (HCC) patients. Experiments in tumor-bearing mice were further designed in order to explore the effects of KLT on the immune system and the underlying molecular mechanisms. The results showed that KLT improves the tumor cell transplantation-induced reduction in the serum level of the cytokines IFN‑γ and IL‑2, and rescues the levels of CD4+ T cells in host mice. These events enhanced the cytotoxic activities of natural killer and CD8+ T cells against the hepatic HepG2 cancer cells. KLT administration further increased the mRNA level of certain nuclear factor κB (NF‑κB)‑responsive genes in CD4+ cells. The chromatin immunoprecipitation assay showed that KLT increases the association of the NF-κB p65 subunit to the promoter regions of interleukin (IL)-2- and B-cell lymphoma (Bcl)-2-encoding genes in CD4+ T cells. Our study demonstrated that KLT is the main active ingredient of coix seed exhibiting anticancer and immunomodulatory properties. Induction of NF-κB‑mediated gene transcription in CD4+ T cells is involved in the immunomodulatory activity of KLT.

Hepatocellular carcinoma: novel molecular targets in carcinogenesis for future therapies

BACKGROUND

Hepatocellular carcinoma is one of the most common and lethal malignant tumors worldwide. Over the past 15 years, the incidence of HCC has more than doubled. Due to late diagnosis and/or advanced underlying liver cirrhosis, only limited treatment options with marginal clinical benefit are available in up to 70% of patients. During the last decades, no effective conventional cytotoxic systemic therapy was available contributing to the dismal prognosis in patients with HCC. A better knowledge of molecular hepatocarcinogenesis provides today the opportunity for targeted therapy.

MATERIALS AND METHODS

A search of the literature was made using cancer literature, the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: "hepatocellular carcinoma," "molecular hepatocarcinogenesis," "targeted therapy," and "immunotherapy."

DISCUSSION AND CONCLUSION

Treatment decisions are complex and dependent upon tumor staging, presence of portal hypertension, and the underlying degree of liver dysfunction. The knowledge of molecular hepatocarcinogenesis broadened the horizon for patients with advanced HCC. During the last years, several molecular targeted agents have been evaluated in clinical trials in advanced HCC. In the future, new therapeutic options will be represented by a blend of immunotherapy-like vaccines and T-cell modulators, supplemented by molecularly targeted inhibitors of tumor signaling pathways.

HCA519/TPX2: a potential T-cell tumor-associated antigen for human hepatocellular carcinoma

Background

Immunotherapy for human hepatocellular cancer (HCC) is slowly making progress towards treating these fatal cancers. The identification of new antigens can improve this approach. We describe a possible new antigen, hepatocellular carcinoma‐associated antigen‐519/targeting protein for Xklp‐2 (HCA519/TPX2), for HCC that might be beneficial for T‐cell specific HCC immunotherapy.

Methods

HCC was studied for the expression for 15 tumor‐associated antigens considered useful for immunotherapy within three HCC cell lines (HepG2, Hep3B, and PLC/PRF/5), lymphocytes, non‐cancerous livers, and clinical HCC. The expression of tumor antigenic precursor proteins (TAPPs) messenger RNA was first screened by reverse transcriptase quantitative real‐time polymerase chain reaction.

Results

Four antigens (alpha fetoprotein, aspartyl/asparaginyl β­hydroxylase, glypican­3 and HCA519/TPX2) proved to be the best expressed TAPPs within the HCC specimens by molecular analyses. HCA519/TPX2 was detected by intracellular cell flow cytometry within HCC cell lines by using a specific antibody towards this TAPP. This antibody also detected the protein within primary HCCs. We synthesized two HCA519/TPX2 peptides (HCA519_464–472 and HCA519_351–359) which can bind to human leukocyte antigen (HLA)‐A*0201. Dendritic cells pulsed with these peptides stimulated cytolytic T lymphocytes (CTLs). These killer T‐cells lysed HLA‐A*0201+ T2 cells exogenously loaded with the correct specific peptide. The CTLs killed HepG2 (HLA‐A2+ and HCA519+), but not the Hep3B and PLC/PRF/5 cell lines, which are HCA519+ but HLA‐A2‐negative. In silico analysis reveals that HCA519/TPX2 has the inherent ability to bind to a very wide variety of HLA antigens.

Conclusion

HCA519/TPX2 is a viable immunotarget that should be further investigated within HCC patients.

Treating advanced hepatocellular carcinoma: How to get out of first gear

Hepatocellular carcinoma is a common malignancy with a poor prognosis. Sorafenib is the only systemic therapy known to improve the overall survival of patients with advanced disease. The clinical benefit of sorafenib is modest and the mechanistic basis for its activity is unknown. Four phase 3 clinical trials have failed to improve on sorafenib in the frontline setting and no agent has been shown to impact outcomes after sorafenib failure. Several factors have contributed to this recent stall in drug development but new approaches hold promise and currently are being investigated. This review will focus on the current pipeline of experimental therapeutics for patients with advanced hepatocellular carcinoma and shed a light on scientific limitations that hamper the advancement of new therapies for this disease, and ways around it.

Novel aspects of the liver microenvironment in hepatocellular carcinoma pathogenesis and development

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer that is derived from hepatocytes and is characterised by high mortality rate and poor prognosis. While HCC is driven by cumulative changes in the hepatocyte genome, it is increasingly recognised that the liver microenvironment plays a pivotal role in HCC propensity, progression and treatment response. The microenvironmental stimuli that have been recognised as being involved in HCC pathogenesis are diverse and include intrahepatic cell subpopulations, such as immune and stellate cells, pathogens, such as hepatitis viruses, and non-cellular factors, such as abnormal extracellular matrix (ECM) and tissue hypoxia. Recently, a number of novel environmental influences have been shown to have an equally dramatic, but previously unrecognized, role in HCC progression. Novel aspects, including diet, gastrointestinal tract (GIT) microflora and circulating microvesicles, are now being recognized as increasingly important in HCC pathogenesis. This review will outline aspects of the HCC microenvironment, including the potential role of GIT microflora and microvesicles, in providing new insights into tumourigenesis and identifying potential novel targets in the treatment of HCC.

Systemic therapies in hepatocellular carcinoma: present and future

Hepatocellular carcinoma (HCC) is now the third leading cause of cancer deathsworldwide and is generally presented at an advanced stage, limiting patients' quality of life. The conventional cytotoxic systemic therapy has proved to be ineffective in HCC, since its induction several decades ago. Today it is possible to use our knowledge of molecular hepatocarcinogenesis to provide a targeted therapy. Sorafenib has demonstrated large improvements in overall survival in HCC. This review describes the molecular mechanisms and potential therapeutic targets, focusing on sorafenib, sunitinib, tivantinib, antiangiogenic agents, and current and future immunotherapies. Thus, it will be necessary in the future to classify HCCs into subgroups according to their genomic and proteomic profiling. The identification of key molecules/receptors/signaling pathways and the assessment of their relevance as potential targets will be the main future challenge potentially influencing response to therapy. Defining molecular targeted agents that are effective for a specific HCC subgroup will hopefully lead to personalized therapy.

Epitope-optimized alpha-fetoprotein genetic vaccines prevent carcinogen-induced murine autochthonous hepatocellular carcinoma

Immunization with effective cancer vaccines can offer a much needed adjuvant therapy to fill the treatment gap after liver resection to prevent relapse of hepatocellular carcinoma (HCC). However, current HCC cancer vaccines are mostly based on native shared-self/tumor antigens that are only able to induce weak immune responses. In this study we investigated whether the HCC-associated self/tumor antigen of alpha-fetoprotein (AFP) could be engineered to create an effective vaccine to break immune tolerance and potently activate CD8 T cells to prevent clinically relevant carcinogen-induced autochthonous HCC in mice. We found that the approach of computer-guided methodical epitope-optimization created a highly immunogenic AFP and that immunization with lentivector expressing the epitope-optimized AFP, but not wild-type AFP, potently activated CD8 T cells. Critically, the activated CD8 T cells not only cross-recognized short synthetic wild-type AFP peptides, but also recognized and killed tumor cells expressing wild-type AFP protein. Immunization with lentivector expressing optimized AFP, but not native AFP, completely protected mice from tumor challenge and reduced the incidence of carcinogen-induced autochthonous HCC. In addition, prime-boost immunization with the optimized AFP significantly increased the frequency of AFP-specific memory CD8 T cells in the liver that were highly effective against emerging HCC tumor cells, further enhancing the tumor prevention of carcinogen-induced autochthonous HCC.

CONCLUSIONS

Epitope-optimization is required to break immune tolerance and potently activate AFP-specific CD8 T cells, generating effective antitumor effect to prevent clinically relevant carcinogen-induced autochthonous HCC in mice. Our study provides a practical roadmap to develop effective human HCC vaccines that may result in an improved outcome compared to the current HCC vaccines based on wild-type AFP.

The EGFR signalling system in the liver: from hepatoprotection to hepatocarcinogenesis

The liver displays an outstanding wound healing and regenerative capacity unmatched by any other organ. This reparative response is governed by a complex network of inflammatory mediators, growth factors and metabolites that are set in motion in response to hepatocellular injury. However, when liver injury is chronic, these regenerative mechanisms become dysregulated, facilitating the accumulation of genetic alterations leading to unrestrained cell proliferation and the development of hepatocellular carcinoma (HCC). The epidermal growth factor receptor (EGFR or ErbB1) signaling system has been identified as a key player in all stages of the liver response to injury, from early inflammation and hepatocellular proliferation to fibrogenesis and neoplastic transformation. The EGFR system engages in extensive crosstalk with other signaling pathways, acting as a true signaling hub for other growth factors, cytokines and inflammatory mediators. Here, we briefly review essential aspects of the biology of the EGFR, the other ErbB receptors, and their ligands in liver injury, regeneration and HCC development. Some aspects of the preclinical and clinical experience with EGFR therapeutic targeting in HCC are also discussed.

Combined immunostimulatory monoclonal antibodies extend survival in an aggressive transgenic hepatocellular carcinoma mouse model

PURPOSE

Immunostimulatory monoclonal antibodies (ISmAb) that unleash antitumor immune responses are showing efficacy in cancer clinical trials. Anti-B7-H1 (PD-L1) monoclonal antibodies (mAb) block a critical inhibitory pathway in T cells, whereas anti-CD137 and OX40 mAbs provide T-cell costimulation. A combination of these ISmAbs (anti-CD137 + anti-OX40 + anti-B7-H1) was tested using a transgenic mouse model of multifocal and rapidly progressing hepatocellular carcinoma, in which c-myc drives transformation and cytosolic ovalbumin (OVA) is expressed in tumor cells as a model antigen.

EXPERIMENTAL DESIGN

Flow-cytometry and immunohistochemistry were used to quantify tumor-infiltrating lymphocytes (TIL) elicited by treatment and assess their activation status and cytolytic potential. Tolerance induction and its prevention/reversal by treatment with the combination of ISmAbs were revealed by in vivo killing assays.

RESULTS

The triple combination of ISmAbs extended survival of mice bearing hepatocellular carcinomas in a CD8-dependent fashion and synergized with adoptive T-cell therapy using activated OVA-specific TCR-transgenic OT-1 and OT-2 lymphocytes. Mice undergoing therapy showed clear increases in tumor infiltration by activated and blastic CD8(+) and CD4(+) T lymphocytes containing perforin/granzyme B and expressing the ISmAb-targeted receptors on their surface. The triple combination of ISmAbs did not result in enhanced OVA-specific cytotoxic T lymphocyte (CTL) activity but other antigens expressed by cell lines derived from such hepatocellular carcinomas were recognized by endogenous TILs. Adoptively transferred OVA-specific OT-1 lymphocytes into tumor-bearing mice were rendered tolerant, unless given the triple mAb therapy.

CONCLUSION

Extension of survival and dense T-cell infiltrates emphasize the translational potential of combinational immunotherapy strategies for hepatocellular carcinoma. Clin Cancer Res; 19(22); 6151-62. ©2013 AACR.

Combination of radiofrequency ablation and sequential cellular immunotherapy improves progression-free survival for patients with hepatocellular carcinoma

Hepatocellular carcinoma (HCC) recurs frequently after minimally invasive therapy. The aim of our study was to observe the efficiency and safety of the combined treatment of radiofrequency ablation (RFA) with cellular immunotherapy (CIT) for HCC patients. In our study, 62 patients with HCC who were treated with radical RFA were divided into two groups: RFA alone (32 patients) and RFA/CIT (30 patients). Autologous mononuclear cells were collected from the peripheral blood and separated by apheresis, and then induced into natural killer (NK) cells, γδT cells and cytokine-induced killer (CIK) cells. These cells were identified by flow cytometry with their specific antibodies and then were infused intravenously to RFA/CIT patients for three or six courses. The tumor recurrent status of these patients was evaluated with computed tomography or magnetic resonance imaging every 3 months after RFA. Progression-free survival (PFS), liver function, viral load and adverse effects were examined. The results implied that PFS was higher in RFA/CIT group than that in RFA group. In RFA/CIT group, six courses had better survival prognosis than three courses. Viral load of hepatitis C was decreased in two of three patients without antiviral therapy in RFA/CIT group, but was increased in RFA group. No significant adverse reaction was found in the patients with CIT. In summary, these preliminary results suggest that combination of sequential CIT with RFA for HCC patients was efficient and safe, and may be helpful in the prevention of the recurrence for the patients with HCC after RFA.

Immunomodulatory effect of Stichopus japonicus acid mucopolysaccharide on experimental hepatocellular carcinoma in rats

Stichopus japonicus acid mucopolysaccharide (SJAMP) is an important biologically active compound that can be extracted from the body wall of the sea cucumber. The present study investigated the anti-tumor and immunomodulatory effects of SJAMP in an experimental hepatocellular carcinoma (HCC) model in rats. Three doses of SJAMP (17.5 mg/kg, 35 mg/kg, and 70 mg/kg administered 5 days/week via oral gavage) were given to rats with diethylnitrosamine (DEN)-induced HCC. SJAMP treatment significantly inhibited DEN-induced HCC by reducing both the number and mean volume of nodules, decreasing serum a-fetoprotein (AFP) levels and proliferating cell nuclear antigen (PCNA) expression in liver, and increasing p21 expression. Furthermore, SJAMP decreased the serum levels of ALT, AST, GGT and TNF-α and increased serum IL-2. SJAMP administration also improved indices of spleen and thymus function and improved both macrophage phagocytosis and NK cell-mediated tumoricidal activity. Moreover, CD3+ and CD4+ T lymphocyte levels recovered significantly and the CD4+/CD8+ T cell ratio normalized in a dose-dependent manner. In conclusion, SJAMP effectively inhibited the growth of HCC through the stimulation of immune organs and tissue proliferation, leading to the enhancement of cellular immunity pathways in rats.

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.

Gastrodin stimulates anticancer immune response and represses transplanted H22 hepatic ascitic tumor cell growth: Involvement of NF-κB signaling activation in CD4+ T cells

Gastrodia elata Blume (G. elata) is a famous restorative food in East Asia. It can be used as an auxiliary reagent in hepatocellular carcinoma (HCC) treatment. Previous studies unveiled that G. elata exhibited immunomodulatory activities. To explore the active ingredients contributing to its immunomodulatory activities, gastrodin, vanillin, and parishin B were purified from G. elata and their anti-HCC effects were assessed in vivo. Among these compounds, only gastrodin was capable of repressing transplanted H22 ascitic hepatic tumor cell growth in vivo with low toxicity. Further investigations were designed to explore the effects of gastrodin on the immune system of tumor-bearing mice and potential molecular mechanisms underlying these effects. Our data showed that gastrodin ameliorated tumor cell transplantation-induced activation of endogenous pro-apoptotic pathway in CD4+ T cells and abnormalities in serum cytokine profiles in host animals. These events enhanced cytotoxic activities of natural killer and CD8+ T cells against H22 hepatic cancer cells. Gastrodin administration specifically upregulated mRNA levels of several nuclear factor κB (NF-κB) responsive genes in CD4+ T cells but not in CD8+ T cells. Chromatin immunoprecipitation assay showed that gastrodin increased the association of NF-κB p65 subunit to the promoter regions of IL-2 and Bcl-2 encoding genes in CD4+ T cells. Our investigations demonstrated that gastrodin is the main active ingredient contributing to the anticancer immunomodulatory properties of G. elata. Promoting NF-κB-mediated gene transcription in CD4+ T cells is implicated in its immunomodulatory activity.

Cellular and molecular mechanisms of hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor that accounts for ~80 % of all liver cancer cases worldwide. It is a multifactorial disease caused by a variety of risk factors and often develops in the background of underlying cirrhosis. A number of cellular phenomena, such as tumor microenvironment, inflammation, oxidative stress, and hypoxia act in concert with various molecular events to facilitate tumor initiation, progression, and metastasis. The emergence of microRNAs and molecular-targeted therapies adds a new dimension in our efforts to combat this deadly disease. Intense research in this multitude of areas has led to significant progress in our understanding of cellular processes and molecular mechanisms that occur during multistage events that lead to hepatocarcinogenesis. In this review, we discuss the current knowledge of HCC, focusing mainly on advances that have occurred during the past 5 years and on the development of novel therapeutics for liver cancer.