Induction of immunosuppressive molecules and regulatory T cells counteracts the antitumor effect of interleukin-12-based gene therapy in a transgenic mouse model of liver cancer

The current status and future of PD-L1 in liver cancer

The application of immunotherapy in tumor, especially immune checkpoint inhibitors (ICIs), has played an important role in the treatment of advanced unresectable liver cancer. However, the efficacy of ICIs varies greatly among different patients, which has aroused people's attention to the regulatory mechanism of programmed death ligand-1 (PD-L1) in the immune escape of liver cancer. PD-L1 is regulated by multiple levels and signaling pathways in hepatocellular carcinoma (HCC), including gene variation, epigenetic inheritance, transcriptional regulation, post-transcriptional regulation, and post-translational modification. More studies have also found that the high expression of PD-L1 may be the main factor affecting the immunotherapy of liver cancer. However, what is the difference of PD-L1 expressed by different types of cells in the microenvironment of HCC, and which type of cells expressed PD-L1 determines the effect of tumor immunotherapy remains unclear. Therefore, clarifying the regulatory mechanism of PD-L1 in liver cancer can provide more basis for liver cancer immunotherapy and combined immune treatment strategy. In addition to its well-known role in immune regulation, PD-L1 also plays a role in regulating cancer cell proliferation and promoting drug resistance of tumor cells, which will be reviewed in this paper. In addition, we also summarized the natural products and drugs that regulated the expression of PD-L1 in HCC.

Hepatocellular carcinoma (HCC) immunotherapy by anti-PD-1 monoclonal antibodies: A rapidly evolving strategy

Hepatocellular carcinoma (HCC) is one of the deadliest cancers in the world, with a high relapse rate. Delayed symptom onset observed in 70-80% of patients leads to diagnosis in advanced stages commonly associated with chronic liver disease. Programmed cell death protein 1 (PD-1) blockade therapy has recently emerged as a promising therapeutic option in the clinical management of several advanced malignancies, including HCC, due to the activation of exhausted tumor-infiltrating lymphocytes and improved outcomes of T-cell function. However, many people with HCC do not respond to PD-1 blockade therapy, and the diversity of immune-related adverse events (irAEs) restricts their clinical utility. Therefore, numerous effective combinatory strategies, including combinations with anti-PD-1 antibodies and other therapeutic methods ranging from chemotherapy to targeted therapies, are evolving to improve therapeutic outcomes and evoke synergistic anti-tumor impressions in patients with advanced HCC. Unfortunately, combined therapy may have more side effects than single-agent treatment. Nonetheless, identifying appropriate predictive biomarkers can aid in managing potential immune-related adverse events by distinguishing patients who respond best to PD-1 inhibitors as single agents or in combination strategies. In the present review, we summarize the therapeutic potential of PD-1 blockade therapy for advanced HCC patients. Besides, a glimpse of the pivotal predictive biomarkers influencing a patient's response to anti-PD-1 antibodies will be provided.

Roles of Therapeutic Bioactive Compounds in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is due to poor prognosis and lack of availability of effective treatment. Novel therapeutic strategies will be the fine tuning of intracellular ROS signaling to effectively deprive cells of ROS-induced tumor-promoting events. This review discusses the generation of ROS, the major signaling their modulation in therapeutics. We explore some of the major pathways involved in HCC, which include the VEGF, MAPK/ERK, mTOR, FGF, and Ser/Thr kinase pathways. In this review, we study cornerstone on natural bioactive compounds with their effect on hepatocarcinomas. Furthermore, we focus on oxidative stress and FDA-approved signaling pathway inhibitors, along with chemotherapy and radiotherapy enhancers which with early evidence of success. While more in vivo testing is required to confirm the findings presented here, our findings will aid future nonclinical, preclinical, and clinical studies with these compounds, as well as inspire medicinal chemistry scientists to conduct appropriate research on this promising natural compound and their derivatives.

Advances in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent disease with a progression that is modulated by the immune system. Systemic therapy is used in the advanced stage and until 2017 consisted only of antiangiogenic tyrosine kinase inhibitors (TKIs). Immunotherapy with checkpoint inhibitors has shown strong anti-tumour activity in a subset of patients and the combination of the anti-PDL1 antibody atezolizumab and the VEGF-neutralizing antibody bevacizumab has or will soon become the standard of care as a first-line therapy for HCC, whereas the anti-PD1 agents nivolumab and pembrolizumab are used after TKIs in several regions. Other immune strategies such as adoptive T-cell transfer, vaccination or virotherapy have not yet demonstrated consistent clinical activity. Major unmet challenges in HCC checkpoint immunotherapy are the discovery and validation of predictive biomarkers, advancing treatment to earlier stages of the disease, applying the treatment to patients with liver dysfunction and the discovery of more effective combinatorial or sequential approaches. Combinations with other systemic or local treatments are perceived as the most promising opportunities in HCC and some are already under evaluation in large-scale clinical trials. This Review provides up-to-date information on the best use of currently available immunotherapies in HCC and the therapeutic strategies under development.

Colon cancer eradication after chemoimmunotherapy is associated with intratumoral emergence of proinflammatory myeloid cells

Interleukin-12 immune stimulation lacks efficacy in established solid tumor models. Disruption of tumor microenvironment homeostasis by low-dose cyclophosphamide prior to interleukin-12 gene therapy led to CD8+ T cell-driven established tumor rejection. This only takes place when inflammatory myeloid cells infiltrate the tumor bed, and is crucial for the latter antitumor response.

Advances in immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent disease with a progression that is modulated by the immune system. Systemic therapy is used in the advanced stage and until 2017 consisted only of antiangiogenic tyrosine kinase inhibitors (TKIs). Immunotherapy with checkpoint inhibitors has shown strong anti-tumour activity in a subset of patients and the combination of the anti-PDL1 antibody atezolizumab and the VEGF-neutralizing antibody bevacizumab has or will soon become the standard of care as a first-line therapy for HCC, whereas the anti-PD1 agents nivolumab and pembrolizumab are used after TKIs in several regions. Other immune strategies such as adoptive T-cell transfer, vaccination or virotherapy have not yet demonstrated consistent clinical activity. Major unmet challenges in HCC checkpoint immunotherapy are the discovery and validation of predictive biomarkers, advancing treatment to earlier stages of the disease, applying the treatment to patients with liver dysfunction and the discovery of more effective combinatorial or sequential approaches. Combinations with other systemic or local treatments are perceived as the most promising opportunities in HCC and some are already under evaluation in large-scale clinical trials. This Review provides up-to-date information on the best use of currently available immunotherapies in HCC and the therapeutic strategies under development.

Sorafenib- Taurine Combination Model for Hepatocellular Carcinoma Cells: Immunological Aspects

Sorafenib (Sor) is a multi-kinase inhibitor. It is recommended for the treatment of advanced hepatocellular carcinoma (HCC). However, Sor has severe and marked side effects. On the other hand, taurine (Tau) has been shown to enhance the therapeutic effects of cancer chemotherapy and also to enhance the function of leukocytes.

Here, we aimed to investigate the enhancing efficacy of Sor as well as minimizing its marked side effects by using Tau in combination in an immunological aspect. We evaluated the influence of Sor and Tau combination on the expression pattern of FOXP3 gene in HepG2 cells compared to peripheral blood mononuclear leukocytes (PBMCs) as control normal cells. Also, the levels of TGF-β and IL-10 released in culture media of both cells were determined. Our results revealed that, Tau reduced cytotoxicity of Sor on PBMC indicated by lactic dehyrogenase (LDH) release assay. In addition, Sor-Tau combination led to FOXP3 down-regulation in hepatic cancer cells (HepG2). The results showed also that, TGF-β levels decreased significantly in their culture media. In contrary, the cytokine increased in PBMCs culture media. Moreover, IL-10 was significantly elevated in the culture media of both cells. This study could open new avenues for the improvement of therapeutic efficacy of Sorafenib treated HCC patients by using Tau in combination.

H2S suppresses indoleamine 2, 3-dioxygenase 1 and exhibits immunotherapeutic efficacy in murine hepatocellular carcinoma

Background

Over-expression and over-activation of immunosuppressive enzyme indoleamine 2, 3 -dioxygenase 1 (IDO1) is a key mechanism of cancer immune escape. However, the regulation of IDO1 has not been fully studied. The relation between hydrogen sulfide (H₂S) and IDO1 is unclear.

Methods

The influences of endogenous and exogenous H₂S on the expression of IDO1, iNOS and NF-κB and STAT3 signaling proteins were investigated using qPCR or western blot, and the production of nitric oxide (NO) was analyzed by nitrate/nitrite assay in Cse^−/− mice and MCF-7 and SGC-7901 cells. The effect of H₂S on IDO1 activity was investigated by HPLC and in-vitro enzymatic assay. The effect of H₂S on tryptophan metabolism was tested by luciferase reporter assay in MCF-7 and SGC-7901 cells. The correlation between H₂S-generating enzyme CSE and IDO1 was investigated by immunostaining and heatmaps analysis in clinical specimens and tissue arrays of hepatocellular carcinoma (HCC) patients. The immunotherapeutic effects of H₂S on H22 HCC-bearing mice were investigated.

Results

Using Cse^−/− mice, we found that H₂S deficiency increased IDO1 expression and activity, stimulated NF-κB and STAT3 pathways and decreased the expression of NO-generating enzyme Inos. Using IDO1-expressing MCF-7 and SGC-7901 cells, we found that exogenous H₂S inhibited IDO1 expression by blocking STAT3 and NF-κB pathways, and decreased IDO1 activity via H₂S/NO crosstalk, and combinedly decreased the tryptophan metabolism. The negative correlation between H₂S-generating enzyme CSE and IDO1 was further validated in clinical specimens and tissue arrays of HCC patients. Additionally, H₂S donors effectively restricted the tumor development in H22 HCC-bearing mice via downregulating IDO1 expression, inducing T-effector cells and inhibiting MDSCs.

Conclusions

Thus, H₂S, as a novel negative regulator of IDO1, shows encouraging antitumor immunotherapeutic effects and represents a novel therapeutic target in cancer therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1083-5) contains supplementary material, which is available to authorized users.

The roles of PD-1/PD-L1 and its signalling pathway in gastrointestinal tract cancers

Cancer immunotherapy has been increasingly applied in the treatment of advanced malignancies. Consequently, immune checkpoints have become a major concern. As PD-1 is an important immunomodulatory protein, the blockade of PD-1 and its ligand PD-L1 is a promising tumour immunotherapy for human carcinoma. In this review, we first discuss the role of the PD-1/PD-L1 interaction in gastrointestinal tract cancers. Targeting PD-1 and PD-L1 in immune cells and tumour cells may show remarkable efficiency in gastrointestinal tract cancers. Second, the PD-1/PD-L1-associated signalling pathway involved in cancer immunotherapy in gastrointestinal tract cancers is discussed. Most importantly, this review summarizes the PD-1/PD-L1-targeted immunotherapy combinations with relevant signalling pathways, which may result in a breakthrough for the treatment of gastrointestinal tract cancers, such as gastric cancer, colorectal cancer and liver cancer. Meanwhile, the review provides a deeper insight into the mechanism of checkpoint blockade immunotherapies.

The therapeutic potential of human adipose-derived mesenchymal stem cells producing CXCL10 in a mouse melanoma lung metastasis model

Interferon γ-induced protein 10 kDa (IP-10) is a potent chemoattractant and has been suggested to enhance antitumor activity and mediate tumor regression through multiple mechanisms of action. Multiple lines of evidence have indicated that genetically-modified adult stem cells represent a potential source for cell-based cancer therapy. In the current study, we assessed therapeutic potential of human adipose derived mesenchymal stem cells (hADSC) genetically-modified to express IP-10 for the treatment of lung metastasis in an immunocompetent mouse model of metastatic melanoma. A Piggybac vector encoding IP-10 was employed to transfect hADSC ex vivo. Expression and bioactivity of the transgenic protein from hADSCs expressing IP-10 were confirmed prior to in vivo studies. Our results indicated that hADSCs expressing IP-10 could inhibit the growth of B16F10 melanoma cells and significantly prolonged survival. Immunohistochemistry analysis, TUNEL assay and western blot analysis indicated that hADSCs expressing IP-10 inhibited tumor cell growth, hindered tumor infiltration of Tregs, restricted angiogenesis and significantly prolonged survival. In conclusion, our results demonstrated that targeting metastatic tumor sites by hADSC expressing IP-10 could reduce melanoma tumor growth and lung metastasis.

Immune checkpoint inhibitors in gastrointestinal malignancies

Gastrointestinal (GIT) tumors are extremely fatal and lethal tumors with limited therapeutic options. Antitumor immunity is new line of research in management of solid tumors. Immune check points are negative regulators of immune system and control the immune response. These checkpoints are exploited by cancer cells. Cancer cells causes early activation of checkpoints and suppress the immune response, and therefore have unchecked growth and metastasis of malignant cells. Immune checkpoint inhibitors (ICIs), downregulates these checkpoints and activate the proliferation of cytotoxic T cells which helps in lysis of tumor cells. ICIs have shown the promising results in management of melanoma, non-small cell lung cancer and renal cell carcinoma. Encouraged by their recent success in solid tumors many clinical trials are ongoing to evaluate their efficacy in GIT tumors. In this article we will try to explain rationale for use of ICIs in GIT tumors. We will summarize the ongoing research, preliminary results and future aspects of ICIs in GIT malignancies.

Lack of MHC class II molecules favors CD8+ T-cell infiltration into tumors associated with an increased control of tumor growth

Regulatory T-cells (Tregs) are crucial for the maintenance of immune tolerance and homeostasis as well as for preventing autoimmune diseases, but their impact on the survival of cancer patients remains controversial. In the TC-1 mouse model of human papillomavirus (HPV)-related carcinoma, we have previously demonstrated that the therapeutic efficacy of the CyaA-E7-vaccine, targeting the HPV-E7 antigen, progressively declines with tumor growth, in correlation with increased intratumoral recruitment of Tregs. In the present study, we demonstrated that these TC-1 tumor-infiltrating Tregs were highly activated, with increased expression of immunosuppressive molecules. Both intratumoral effector CD4⁺ T-cells (Teffs) and Tregs expressed high levels of PD-1, but anti-PD-1 antibody treatment did not impact the growth of the TC-1 tumor nor restore the therapeutic effect of the CyaA-E7 vaccine. To analyze the mechanisms by which Tregs are recruited to the tumor site, we used MHC-II KO mice with drastically reduced numbers of CD4⁺ effector T-cells. We demonstrated that these mice still had significant numbers of Tregs in their lymphoid organs which were recruited to the tumor. In MHC-II KO mice, the growth of the TC-1 tumor was delayed in correlation with a strong increase in the intratumoral recruitment of CD8⁺ T-cells. In addition, in mice that spontaneously rejected their tumors, the infiltration of E7-specific CD8⁺ T-cells was significantly higher than in MHC-II KO mice with a growing tumor. These results demonstrate that tumor-specific CD8⁺ T-cells can be efficiently activated and recruited in the absence of MHC class II molecules and of CD4⁺ T-cell help.

Immune checkpoint inhibition: prospects for prevention and therapy of hepatocellular carcinoma

The global prevalence of liver cancer is rapidly rising, mostly as a result of the amplified incidence rates of viral hepatitis, alcohol abuse and obesity in recent decades. Treatment options for liver cancer are remarkably limited with sorafenib being the gold standard for advanced, unresectable hepatocellular carcinoma but offering extremely limited improvement of survival time. The immune system is now recognised as a key regulator of cancer development through its ability to protect against infection and chronic inflammation, which promote cancer development, and eliminate tumour cells when present. However, the tolerogenic nature of the liver means that the immune response to infection, chronic inflammation and tumour cells within the hepatic environment is usually ineffective. Here we review the roles that immune cells and cytokines have in the development of the most common primary liver cancer, hepatocellular carcinoma (HCC). We then examine how the immune system may be subverted throughout the stages of HCC development, particularly with respect to immune inhibitory molecules, also known as immune checkpoints, such as programmed cell death protein-1, programmed cell death 1 ligand 1 and cytotoxic T lymphocyte antigen 4, which have become therapeutic targets. Finally, we assess preclinical and clinical studies where immune checkpoint inhibitors have been used to modify disease during the carcinogenic process. In conclusion, inhibitory molecule-based immunotherapy for HCC is in its infancy and further detailed research in relevant in vivo models is required before its full potential can be realised.

Serum interleukin measurement may help identify thyroid cancer patients with active disease

BACKGROUND

Investigate the clinical utility of serum interleukin dosages of IL-2, IL-2R, IL-4, IL-6, IL-6R, IL-8, IL-10 and IL-12 in the diagnosis and characterization of patients with DTC. In particular, verify ILs utility in the identification of individuals who are evolving disease-free or with the active disease.

METHODS

We evaluated 200 patients with malignant nodules (100 patients disease-free and 100 patients with recurrence/active disease); 60 benign nodules and 100 healthy controls, serum levels were assessed by ELISA.

RESULTS

All ILs, but not IL-4, differentiated these three groups. We observed that IL-2, 2R and 10 serum concentrations were associated with thyroglobulin levels. Serum IL-2 was able to differentiate patients with active disease from the disease-free with a sensitivity of 98%, specificity of 58%, positive predictive value (PPV) of 70% and negative predictive value (NPV) of 97% (p=0.0007). IL-6R levels differentiated patients with active disease from the disease-free patients with 56% sensitivity, 63% specificity, PPV of 60% and NPV of 59% (p<0.0001). IL-8 values also distinguished patients with active disease from the disease-free ones with sensitivity of 50%, specificity of 76%, PPV of 68% and NPV of 60% (p=0.0025); using IL-12, we obtained a sensitivity value of 73%, specificity of 66%, PPV of 68% and NPV of 71% (p<0.0001). Furthermore, interleukin levels showed association with some tumor characteristics of aggressiveness.

CONCLUSION

We suggest that the serum concentration of ILs may assist in the diagnosis and characterization of tumor malignancy helping identify patients with active disease who deserve closer medical attention.

Association of Interleukin-12A rs568408 with Susceptibility to Asthma in Taiwan

Asthma is an inflammatory disease and interleukin 12 (IL-12) may play a regulatory role in allergen-induced inflammation. The aim of this study was to investigate the association of polymorphisms in IL-12A/IL-12B with asthma. The asthma group included 198 adult patients and the control group included 453 individuals without asthma that were frequency-matched by gender and age. The distribution of genotypic and allelic frequencies of IL-12A rs568408 demonstrated significant differences between case and control groups. Specifically, the percentages of AA genotype of IL-12A rs568408 was significantly higher among asthmatic patients in Taiwan than healthy controls, compared to GG genotype. No significant difference was observed among the IL-12A rs2243115 and IL-12B rs3212227 genotypes between case and control groups. In addition, the A allele at IL-12A rs568408 was associated with more severe symptoms (P = 0.0085) among asthmatic patients. These results suggest that IL-12A rs568408 may contribute to the etiology and symptoms severity of asthma, indicating its usefulness as a predictive and diagnostic biomarker of asthma.

Relevance of CD6-Mediated Interactions in the Regulation of Peripheral T-Cell Responses and Tolerance

The CD6 lymphocyte receptor has been involved in the pathophysiology of different autoimmune disorders and is now considered a feasible target for their treatment. In vitro data show the relevance of CD6 in the stabilization of adhesive contacts between T-cell and antigen-presenting cells, and the modulation of T-cell receptor signals. However, the in vivo consequences of such a function are yet undisclosed due to the lack of suitable genetically modified animal models. Here, the in vitro and in vivo challenge of CD6-deficient (CD6^-/-) cells with allogeneic cells was used as an approach to explore the role of CD6 in immune responses under relative physiological stimulatory conditions. Mixed lymphocyte reaction (MLR) assays showed lower proliferative responses of splenocytes from CD6^-/- mice together with higher induction of regulatory T cells (T_reg, CD4⁺CD25⁺FoxP3⁺) with low suppressive activity on T and B-cell proliferation. In line with these results, CD6^-/- mice undergoing a lupus-like disorder induced by chronic graft-versus-host disease (cGvHD) showed higher serum titers of anti-double-stranded DNA and nucleosome autoantibodies. This occurred together with reduced splenomegaly, which was associated with lower in vivo bromodesoxyuridine incorporation of spleen cells and with increased percentages of spleen follicular B cells (B2, CD21⁺CD23^hi) and T_reg cells. Interestingly, functional analysis of in vivo-generated CD6^-/- T_reg cells exhibited defective suppressive activity. In conclusion, the data from MLR and cGvHD-induced lupus-like models in CD6^-/- mice illustrate the relevance of CD6 in T (and B) cell proliferative responses and, even more importantly, T_reg induction and suppressive function in the in vivo maintenance of peripheral tolerance.

Prospect of the use of checkpoint inhibitors in hepatocellular cancer treatments

Hepatocellular cancer (HCC) is a very fatal disease due to limited therapeutic options as well as due to its association with underlying chronic liver disease in the majority of cases. The immune evasion in HCC signifies a major barrier to the delivery of effective immunotherapy. Sorafenib is the only Food and Drug Administration-approved drug available with an overall response rate of 2%–3% and overall survival of 2.8 months. Chemotherapy has not been used routinely because of the relative refractoriness of advanced HCC. The introduction of immune checkpoint inhibitors (cytotoxic T-lymphocyte antigen 4, programmed death 1, and programmed death-ligand 1) has opened a new horizon for cancer immunotherapy. Future direction in immunotherapy for HCC is to rationally combine it with other treatment modalities, including surgery, radiofrequency ablation, and cytotoxic agents, to maximize its therapeutic efficacy.

Tumor regulation of the tissue environment in the liver

The tumor microenvironment (TME) in the liver plays an important role in primary and metastatic liver tumor formation and tumor growth promotion. Cellular and non-cellular components of the TME significantly influence tumor development, growth, metastatic spread, anti-tumor immunity and response to tumor therapy. The cellular components of the TME in the liver not only consist of infiltrating immune cells, but also of liver-resident cells such as liver sinusoidal endothelial cells (LSEC) and hepatic stellate cells (HSC), which promote tumor growth by negatively regulating tumor-associated immune responses. In this review, we characterize cells of the TME with pro- and anti-tumor function in primary and metastatic liver tumors. Furthermore, we summarize mechanisms that permit growth of hepatic tumors despite the occurrence of spontaneous anti-tumor immune responses and how novel therapeutic approaches targeting the TME could unleash tumor-specific immune responses to improve survival of liver cancer patients.

Insights into the Role and Interdependence of Oxidative Stress and Inflammation in Liver Diseases

The crucial roles of oxidative stress and inflammation in the development of hepatic diseases have been unraveled and emphasized for decades. From steatosis to fibrosis, cirrhosis and liver cancer, hepatic oxidative stress, and inflammation are sustained and participated in this pathological progressive process. Notably, increasing evidences showed that oxidative stress and inflammation are tightly related, which are regarded as essential partners that present simultaneously and interact with each other in various pathological conditions, creating a vicious cycle to aggravate the hepatic diseases. Clarifying the interaction of oxidative stress and inflammation is of great importance to provide new directions and targets for developing therapeutic intervention. Herein, this review is concerned with the regulation and interdependence of oxidative stress and inflammation in a variety of liver diseases. In addition to classical mediators and signaling, particular emphasis is placed upon immune suppression, a potential linkage of oxidative stress and inflammation, to provide new inspiration for the treatment of liver diseases. Furthermore, since antioxidation and anti-inflammation have been extensively attempted as the strategies for treatment of liver diseases, the application of herbal medicines and their derived compounds that protect liver from injury via regulating oxidative stress and inflammation collectively were reviewed and discussed.

Targeting inhibition of Foxp3 by a CD28 2'-Fluro oligonucleotide aptamer conjugated to P60-peptide enhances active cancer immunotherapy

The specific inhibition of Treg function has long been a major technical challenge in cancer immunotherapy. So far no single cell-surface marker has been identified that could be used to distinguish Treg cells from other lymphocytes. The only available specific marker mostly expressed in Treg is Foxp3, which is an intracellular transcription factor. A targeting molecule able to penetrate the membrane and inhibit Foxp3 within the cell is needed. P60-peptide is able to do that, but due to lack of target specificity, the doses are extremely high. In this study we have shown as a proof of concept that P60 Foxp3 inhibitor peptide can be conjugated with a CD28 targeting aptamer to deliver the peptide to CD28-expressing cells. The AptCD28-P60 construct is a clinically feasible reagent that improves the efficacy of the unconjugated P60 peptide very significantly. This approach was used to inhibit Treg function in a vaccination context, and it has shown a significant improvement in the induced immune response, entailing a lower tumor load in an antigen-specific cancer vaccine protocol.

Gene therapy approaches against cancer using in vivo and ex vivo gene transfer of interleukin-12

IL-12 is an immunostimulatory cytokine with strong antitumor properties. Systemic administration of IL-12 in cancer patients led to severe toxic effects, prompting the development of gene therapy vectors able to express this cytokine locally in tumors. Both nonviral and viral vectors have demonstrated a high antitumor efficacy in preclinical tumor models. Some of these vectors, including DNA electroporation, adenovirus and ex vivo transduced dendritic cells, were tested in patients, showing low toxicity and moderate antitumor efficacy. IL-12 activity can be potentiated by molecules with immunostimulatory, antiangiogenic or cytotoxic activity. These combination therapies are of clinical interest because they could lower the threshold for IL-12 efficacy, increasing the therapeutic potential of gene therapy and preventing the toxicity mediated by this cytokine.

Immunological landscape and immunotherapy of hepatocellular carcinoma

Advanced hepatocellular carcinoma (HCC) is a serious therapeutic challenge and targeted therapies only provide a modest benefit in terms of overall survival. Novel approaches are urgently needed for the treatment of this prevalent malignancy. Evidence demonstrating the antigenicity of tumour cells, the discovery that immune checkpoint molecules have an essential role in immune evasion of tumour cells, and the impressive clinical results achieved by blocking these inhibitory receptors, are revolutionizing cancer immunotherapy. Here, we review the data on HCC immunogenicity, the mechanisms for HCC immune subversion and the different immunotherapies that have been tested to treat HCC. Taking into account the multiplicity of hyperadditive immunosuppressive forces acting within the HCC microenvironment, a combinatorial approach is advised. Strategies include combinations of systemic immunomodulation and gene therapy, cell therapy or virotherapy.

Immune checkpoint blockade in hepatocellular carcinoma: current progress and future directions

Immune checkpoint blockade has recently emerged as a promising therapeutic approach for various malignancies including hepatocellular carcinoma (HCC). Preclinical and clinical studies have shown the potential benefit of modulating the immunogenicity of HCC. In addition, recent advances in tumor immunology have broadened our understanding of the complex mechanism of immune evasion. In this review we summarize the current knowledge on HCC immunology and discuss the potential of immune checkpoint blockade as a novel HCC therapy from the basic, translational, and clinical perspectives.

Special role of Foxp3 for the specifically altered microRNAs in Regulatory T cells of HCC patients

Background

Regulatory T cells (Tregs) exhibit functional abnormalities in the context of hepatocellular carcinoma (HCC). The microRNAs (miRNAs) are identified as the key modulators in Tregs. This study was to explore whether the expression profiles of miRNAs of Tregs were different in HCC-activated Tregs and whether Foxp3 had special effects on them.

Methods

We isolated HCC-activated Tregs from mice bearing HCC and compared the expression profiles of miRNAs between HCC-activated Tregs and control Tregs by microarray. RNA interference against Foxp3 was also performed through transfection of synthetic siRNAs to Tregs for analyzing the effect of Foxp3 on the expression of miRNAs. Tregs isolated from HCC patients (n = 12) and healthy controls (n = 7) were used for validation of the differentially expressed miRNAs. Finally, bioinformatic analysis was applied to infer their possible roles.

Results

We found nine specifically altered miRNAs in HCC-activated Tregs from the murine model. After transfection with siRNAs against Foxp3, control Tregs showed obvious reduction of Foxp3 and five miRNAs were significantly changed; HCC-activated Tregs exhibited a slight reduction of Foxp3 with three miRNAs significantly changed. Tregs from HCC patients and healthy controls finally confirmed the up-regulation of four miRNAs (hsa-miR-182-5p, hsa-miR-214-3p, hsa-miR-129-5p and hsa-miR-30b-5p). Following bioinformatic analysis suggested these altered miRNAs would target eight important signaling pathways that could affect the functions of Tregs.

Conclusions

Our studies provided the first evidence that Tregs in HCC had the specifically altered expression of miRNAs, which was affected by Foxp3. These results are useful both in finding new biomarkers and in further exploring the functions of Tregs in HCC patients.

Harnessing high density lipoproteins to block transforming growth factor beta and to inhibit the growth of liver tumor metastases

Transforming growth factor β (TGF-β) is a powerful promoter of cancer progression and a key target for antitumor therapy. As cancer cells exhibit active cholesterol metabolism, high density lipoproteins (HDLs) appear as an attractive delivery system for anticancer TGFβ-inhibitory molecules. We constructed a plasmid encoding a potent TGF-β-blocking peptide (P144) linked to apolipoprotein A-I (ApoA-I) through a flexible linker (pApoLinkerP144). The ApoLinkerP144 sequence was then incorporated into a hepatotropic adeno-associated vector (AAVApoLinkerP144). The aim was to induce hepatocytes to produce HDLs containing a modified ApoA-I capable of blocking TGF-β. We observed that transduction of the murine liver with pApoLinkerP144 led to the appearance of a fraction of circulating HDL containing the fusion protein. These HDLs were able to attenuate TGF-β signaling in the liver and to enhance IL-12 -mediated IFN-γ production. Treatment of liver metastasis of MC38 colorectal cancer with AAVApoLinkerP144 resulted in a significant reduction of tumor growth and enhanced expression of IFN-γ and GM-CSF in cancerous tissue. ApoLinkerP144 also delayed MC38 liver metastasis in Rag2^−/−IL2rγ^−/− immunodeficient mice. This effect was associated with downregulation of TGF-β target genes essential for metastatic niche conditioning. Finally, in a subset of ret transgenic mice, a model of aggressive spontaneous metastatic melanoma, AAVApoLinkerP144 delayed tumor growth in association with increased CD8⁺ T cell numbers in regional lymph nodes. In conclusion, modification of HDLs to transport TGF-β-blocking molecules is a novel and promising approach to inhibit the growth of liver metastases by immunological and non-immunological mechanisms.

Improving immunotherapy of hepatocellular carcinoma (HCC) using dendritic cells (DC) engineered to express IL-12 in vivo

BACKGROUND

Interleukin 12 (IL-12), one of the most potent Th1-cytokines, has been used to improve dendritic cells (DC)-based immunotherapy of cancer. However, it failed to achieve clinical response in patients with hepatocellular carcinoma (HCC). In this study, improved conditions of immunotherapy with DC engineered to express IL-12 were studied in murine subcutaneous HCC.

METHODS

Tumour-lysate pulsed DC were transduced with IL-12-encoding adenoviruses or cultivated with recombinant (r)IL-12. DC were injected intratumourally, subcutaneously or intravenously at different stages of tumour-development.

RESULTS

Dendritic cell overexpressing IL-12 by adenoviruses showed enhanced expression of costimulatory molecules and stronger priming of HCC-specific effector cells than DC cultured with rIL-12. Intratumoural but not systemic injections of IL-12-DC induced the strongest antitumoural effects reaching complete regressions in 75% of early-staged tumours and in 33% of advanced tumours. Importantly, antitumoural effects could be further enhanced through combination with sorafenib. Analysing the tumour-environment, IL-12-DC increased the levels of Th1-cytokines/chemokines and of CD4(+) -, CD8(+) -T- and NK-cells. Induced immunity was tumour-specific and sustained since all tumour-free animals were protected towards hepatic tumour-cell rechallenge. However, IL-12-DC also enhanced immunosuppressive cytokines, regulatory T cells and even myeloid-derived suppressor cells within the tumours.

CONCLUSIONS

Induced IL-12-overexpression by adenoviral vectors can effectively immunostimulate DC. Intratumoural but not systemic injection of activated IL-12-DC was crucial for effective tumour regression. The mechanism of this approach seems to be the induction of a sufficient Th1 tumour-environment allowing the recruitment of effector cells rather than the inhibition of tumour immunosuppression. Thus, improved immunotherapy with IL-12-DC represents a promising approach towards HCC.

Short-term intratumoral interleukin-12 expressed from an alphaviral vector is sufficient to induce an efficient antitumoral response against spontaneous hepatocellular carcinomas

Interleukin-12 (IL-12) is an immunostimulatory cytokine that has shown strong antitumor effects in animal models of liver cancer. In order to overcome the severe toxicity associated with its systemic administration, we had previously tested different strategies based on IL-12 gene transfer to tumor cells or to the surrounding liver tissue. We obtained promising results both with a recombinant Semliki Forest virus (SFV) vector expressing high levels of IL-12 (SFV-IL-12) after intratumoral injection and with a plasmid vector [pTonL2(T)-mIL12] that allows liver-specific and inducible IL-12 expression. The aim of the present study was to compare the antitumor responses induced by both systems in a clinically relevant animal model of hepatocellular carcinoma (HCC) developed in L-PK/c-myc transgenic mice. These animals overexpress the c-myc oncogene in their livers, giving rise to spontaneous hepatic tumors with latency, histopathology, and genetic characteristics similar to human HCCs. We observed that intratumoral inoculation of SFV-IL-12 induced growth arrest in most tumors, providing 100% survival rate, in contrast to no survival in control animals. Similar results were obtained with hydrodynamic injection of pTonL2(T)-mIL12 after long-term induction of IL-12 expression in the liver. However, tumor arrest was less evident in plasmid-treated mice and the survival rate was slightly lower, despite higher and more sustained levels of IL-12 and IFN-γ in serum. The fact that SFV-IL-12 was able to induce both apoptosis and a type-I IFN response specifically in the tumor could explain why short-term IL-12 expression from this vector was sufficient to mediate an antitumoral response comparable with long-term IL-12 expression driven by pTonL2(T)-mIL12. Since SFV-IL-12 could reduce the possible toxicity associated with long-term IL-12 expression, we believe that this vector could have a potential application for HCC gene therapy.

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.

Association of interleukin-12 polymorphisms and serum IL-12p40 levels with osteosarcoma risk

No previous studies reported the association of IL-12 polymorphisms with osteosarcoma. We aimed to investigate the association in a Chinese population. IL-12A rs568408, rs2243115, and IL-12B rs3212227 polymorphisms were evaluated in a case-control study of 106 osteosarcoma patients and 210 health controls by using polymerase chain reaction-restriction fragment length polymorphism. Serum IL-12p40 levels were measured by enzyme-linked immunosorbent assay. The serum IL-12p40 levels were significantly higher in controls than those in osteosarcoma patients (p<0.01). Genotypes of rs568408 GA and GA/AA, and rs3212227 CC and AC/CC were associated with the risk of osteosarcoma (rs568408 GA: odds ratios [OR]=1.86, 95% confidence intervals [CI]=1.11-3.12; GA/AA: OR=1.75, 95% CI=1.06-2.89, and rs3212227 CC: OR=2.70, 95% CI=1.38-5.28; CC/AC: OR=1.73, 95% CI=1.03-2.90). Moreover, rs3212227 CC/AC genotypes were significantly associated with decreased serum IL-12p40 levels in osteosarcoma patients compared to AA genotypes (p=0.035). Stratification analysis showed no associations between rs3212227 variant and the patients' gender, tumor location, and metastasis. Our data suggest that the serum IL-12p40 levels associate with the risk of osteosarcoma and are regulated by IL-12B rs3212227 polymorphism. The IL-12A rs568408 and IL-12B rs3212227 may confer the susceptibility to osteosarcoma risk.

Intra-arterial interleukin-12 gene delivery combined with chemoembolization: anti-tumor effect in a rabbit hepatocellular carcinoma (HCC) model

BACKGROUND

Interleukin-12 (IL-12), a cytokine naturally secreted by activated dendritic cells and monocytes/macrophages, is known as a key anti-tumor agent in many tumor models, including hepatocellular carcinoma (HCC) models.

PURPOSE

To evaluate the anti-tumor effect of intra-arterial IL-12 gene delivery alone and in combination with transcatheter arterial chemoembolization (TACE) in rabbit VX2 liver cancer model.

MATERIAL AND METHODS

Rabbits with VX2 liver tumors were randomized into four groups, eight in each group. After laparotomy and insertion of a 30-gauge needle into the proper hepatic artery, the following interventional procedure protocols were applied: 0.9% saline solution (group A, control), TACE (group B, TACE alone, lipiodol + mitomycin), intra-arterial interleukin-12 gene infusion (group C, IL-12 alone), and intra-arterial interleukin-12 gene infusion in combination with TACE (group D, IL-12 plus TACE). Growth ratio was estimated by computed tomography. To analyze apoptotic index, tumor tissues were explanted for terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) staining, 14 days after therapy.

RESULTS

Significant differences of the relative tumor growth ratio were observed in TACE alone group and IL-12 plus TACE group in comparison with control (P < 0.05, ANOVA, Tukey's HSD correction) but not between IL-12 alone and control, or IL-12 plus TACE group and TACE alone group (P > 0.05). Significant changes of the apoptotic index were observed in group D in comparison with remaining three groups (P < 0.05). The difference between group C and group A was not significant statistically (P > 0.05).

CONCLUSION

Intra-arterial interleukin-12 gene therapy combined with TACE has a potent anti-tumor effect in rabbit VX2 liver cancer in comparison with TACE alone.

Cytokines for the treatment of gastrointestinal cancers: clinical experience and new perspectives

INTRODUCTION

Cytokines are key mediators of the immune system and have been proposed as therapeutic agents against cancer, either as recombinant proteins, or as transgenes in gene therapy approaches. Stimulation of immune responses against cancer cells is an appealing method to treat tumors with high risk of relapse and systemic dissemination.

AREAS COVERED

We provide a critical overview of clinical trials involving the use of cytokines for the treatment of liver, colon and pancreatic cancers. Special attention has been paid to advances in the field of gene therapy and oncolytic viruses. The potential of new developments still in a pre-clinical stage is also discussed. We have revised public sources of information (PubMed, US National Institutes of Health clinical trials database) up to January 2013.

EXPERT OPINION

The complexity of the immune system and the unfavorable pharmacokinetic properties of cytokines limit the efficacy of these molecules as single agents for the treatment of cancer. Expression from gene therapy vectors, together with new methods of targeting and stabilization, may overcome these hurdles. We believe cytokines will play a crucial role as part of combined approaches, enhancing the action of adoptive cell immunotherapy, oncolytic viruses or biological therapies.

Liver gene transfer of interkeukin-15 constructs that become part of circulating high density lipoproteins for immunotherapy

Apolipoprotein A-I (Apo A-I) is a major component of high density lipoproteins (HDL) that transport cholesterol in circulation. We have constructed an expression plasmid encoding a chimeric molecule encompassing interleukin-15 (IL-15) and Apo A-I (pApo-hIL15) that was tested by hydrodynamic injections into mice and was co-administered with a plasmid encoding the sushi domain of IL-15Rα (pSushi) in order to enhance IL-15 trans-presentation and thereby bioactivity. The pharmacokinetics of the Apo A-I chimeric protein were much longer than non-stabilized IL-15 and its bioactivity was enhanced in combination with IL-15Rα Sushi. Importantly, the APO-IL-15 fusion protein was incorporated in part into circulating HDL. Liver gene transfer of these constructs increased NK and memory-phenotype CD8 lymphocyte numbers in peripheral blood, spleen and liver as a result of proliferation documented by CFSE dilution and BrdU incorporation. Moreover, the gene transfer procedure partly rescued the NK and memory T-cell deficiency observed in IL-15Rα^−/− mice. pApo-hIL15+ pSushi gene transfer to the liver showed a modest therapeutic activity against subcutaneously transplanted MC38 colon carcinoma tumors, that was more evident when tumors were set up as liver metastases. The improved pharmacokinetic profile and the strong biological activity of APO-IL-15 fusion protein holds promise for further development in combination with other immunotherapies.

Modulation of regulatory T-cell activity in combination with interleukin-12 increases hepatic tolerogenicity in woodchucks with chronic hepatitis B

Regulatory T cells (Treg) play a critical role in the modulation of immune responses to viral antigens in chronic viral hepatitis. Woodchucks (Marmota monax) infected with the woodchuck hepatitis virus (WHV) represent the best animal model for chronic hepatitis B virus (HBV) infection. Examination of intrahepatic and peripheral Treg in uninfected and WHV chronically infected woodchucks showed a significant increase of intrahepatic Treg numbers in chronically infected animals, whereas no differences were found in peripheral blood. In agreement with these data, higher expression levels of Forkhead box P3 (Foxp3), interleukin (IL)-10, transforming growth factor beta (TGF-β) were detected in the liver of chronic WHV carriers in comparison to uninfected animals. Furthermore, treatment of WHV-infected animals with an adenovirus encoding IL-12 failed to reduce viral load, a finding that was associated with lymphocyte unresponsiveness to IL-12 stimulation in vitro. We observed that TGF-β and Treg play a major role in the lack of lymphocyte response to IL-12 stimulation, as TGF-β inhibition and Treg depletion allowed recovery of T-cell responsiveness to this cytokine. Based on these results, woodchucks were treated with IL-12 in combination with a TGF-β inhibitory peptide or Treg depletion. However, no antiviral effect was achieved and, instead, an enhancement of the intrahepatic tolerogenic environment was observed.

CONCLUSION

Our data show that TGF-β inhibition or Treg depletion had no added benefit over IL-12 therapy in chronic WHV infection. IL-12 immunostimulation induces a strong immunosuppressive reaction in the liver of chronic WHV carriers that counteracts the antiviral effect of the treatment.

Associations between polymorphisms in IL-12A, IL-12B, IL-12Rβ1, IL-27 gene and serum levels of IL-12p40, IL-27p28 with esophageal cancer

PURPOSE

The aim of this study was to investigate whether IL-12A, IL-12B, IL-12Rβ1, and IL-27 gene polymorphisms and serum levels of IL-12, IL-27 are associated with esophageal cancer.

METHODS

We genotyped IL-12A gene rs568408, IL-12B gene rs3212227, IL-12Rβ1 gene 378 C/G, IL-27 gene rs153109, rs17855750, and rs181206 polymorphisms in a case-control study of 426 esophageal cancer patients and 432 health controls, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and serum IL-12p40 and IL-27p28 levels were measured by enzyme-linked immunosorbent assay.

RESULTS

Both serum IL-12p40 and IL-27p28 levels were significantly higher in controls than those in patients (P < 0.01). Rs568408 AG/AA, rs3212227 CC/AC, and IL-12Rβ1 378 GG/GC genotypes were associated with significantly increased risk of esophageal cancer (rs568408: χ(2) = 5.704, P = 0.017; rs3212227: χ(2) = 7.689, P = 0.006; IL-12Rβ1 378C/G: χ(2) = 5.206, P = 0.023). Moreover, rs3212227 CC/AC and 378 GG/GC genotypes were observed significantly associated with decreased serum IL-12p40 level in patients compare to other genotypes (rs3212227: t = 2.129, P = 0.034; IL-12Rβ1 378 C/G: t = 2.178, P = 0.030). Furthermore, frequency of rs3212227 CC/AC genotypes was significantly higher in patients with poor differentiation than those with AA genotype (χ(2) = 4.314, P = 0.035).

CONCLUSION

Our data suggest that the impaired production of IL-12p40 and IL-27p28 behaves as risk factors for esophageal cancer occurrence. IL-12B gene rs3212227 CC/AC and IL-12Rβ1 gene 378 GG/GC genotypes, which associated with decreased IL-12p40 level, may contribute to esophageal cancer susceptibility.

High levels of gene expression in the hepatocytes of adult mice, neonatal mice and tree shrews via retro-orbital sinus hydrodynamic injections of naked plasmid DNA

Hydrodynamic-based gene delivery has emerged as an efficient and simple method for the intracellular transfection of naked plasmid DNA (pDNA) in vivo. In this system, a hydrodynamic injection via the tail vein is the most effective non-viral method of liver-targeted gene delivery. However, this injection is often technically challenging when used in animals whose tail veins are difficult to visualize or too small to operate on. To overcome this limitation, an alternative in vivo gene delivery method, the rapid injection of large volume of pDNA solution through retro-orbital sinus, was established. Using this technique, we successfully delivered pDNA to the tissue of adult mice, neonatal mice and tree shrews. The efficient expression of exogenous genes was specifically detected in the liver of test animals treated with this gene delivery method. This study demonstrates for the first time that the hydrodynamic gene delivery via the retro-orbital sinus can not only reach the same transgene efficiency as a tradition hydrodynamic-based intravascular injection but also be used in animals that are difficult to inject via the tail vein. This method could open up new areas in gene function studies and gene therapy disease treatment.

Perioperative dynamic alterations in peripheral regulatory T and B cells in patients with hepatocellular carcinoma

Background

Intratumoral and circulating regulatory T cells (Tregs) have been shown to be critical in the pathogenesis of hepatocellular carcinoma (HCC). However there is limited knowledge on the alterations of regulatory B cells (Bregs). We here investigated perioperative dynamic alterations of peripheral circulating Tregs and Bregs in HCC patients to reveal the relationship between regulatory lymphocytes and its clinical implications.

Methods

36 patients with HCC, 6 with chronic hepatitis B infection and 10 healthy donors were enrolled for this study. Frequencies of peripheral Tregs and Bregs were measured by flow cytometry with antibodies against CD4, CD25, CD127, CD19 and IL-10 before, and after radical surgery. Then, clinical informatics of HCC patients was achieved through Digital Evaluation Score System (DESS) for the assessment of disease severity. Finally, we analysed correlations between digitalized clinical features and kinetics of circulating regulatory lymphocytes.

Results

Level of circulating CD4⁺CD25⁺CD127^- Tregs in HCC patients was significantly lower than that in healthy donors and patients with chronic hepatitis B infection before surgery, but was increased after surgery. Preoperative level of CD19⁺ IL-10⁺ Bregs in HCC patients was also significantly lower than the other groups. However it dramatically was elevated right after surgery and remained elevated compared to controls (about 7 days after surgery, P = 0.04). Frequency of circulating Tregs was correlated with circulating leukocytes, ferritin, and clinical features suggesting tumor aggressiveness including portal vein thrombosis, hepatic vein involvement and advanced clinical stages. Frequency of circulating Bregs was associated with Hepatitis B e Antigen (HBeAg) and Hepatitis B virus (HBV) DNA copy number. In addition, DESS was significantly and positively correlated with other staging systems.

Conclusion

Frequencies of peripheral Tregs and Bregs in HCC patients increased after surgery. These results suggest that a postoperative combination of therapies against Tregs and Bregs may be beneficial for better outcome of HCC patients after resection.

Association of single nucleotide polymorphisms in IL-12 and IL-27 genes with colorectal cancer risk

OBJECTIVES

Interleukin-12 (IL-12) plays an important role in antitumor immunity. Interleukin-27 (IL-27) is a novel IL-12 family member. The present studies demonstrate that IL-27 mediates potent antitumor activity. However, No studies have examined the association of these polymorphism with colorectal cancer (CRC). Therefore, we investigated the relationship of IL-12 and IL-27 gene polymorphisms and CRC.

DESIGN AND METHODS

We analyzed polymorphisms of IL-12 gene 16974 A/C and IL-27 gene -964 A/G, 2905 T/G, 4730 T/C in 410 patients with CRC and 450 controls, using PCR-RFLP method.

RESULTS

There were no significant differences in the genotype and allele frequencies of IL-12 and IL-27 gene polymorphisms between the group of patients with CRC and the controls. Furthermore, no association was found between IL-12 family gene polymorphisms and different clinical stages in patients with CRC.

CONCLUSION

These findings suggest that IL-12 and IL-27 gene polymorphisms may not be involved in susceptibility to CRC.

Therapeutic targeting of B7-H1 in breast cancer

INTRODUCTION

Breast cancer is the most common form of malignancy occurring in women worldwide. B7-H1 is a co-inhibitory molecule expressed by several types of tumors, including breast cancer. The aberrant expression of B7-H1 in breast cancer cells has been determined, its role in recruiting regulatory T cells into the tumor microenvironment has been elucidated and a strong link to B7-H1 induction in highly proliferative breast cancer has been provided. It has also been demonstrated that doxorubicin, a drug commonly used for breast cancer treatment, downregulates the cell surface expression of B7-H1 and upregulates its nuclear expression, which therefore suggests an anti-apoptotic role of B7-H1 in breast cancer.

AREAS COVERED

This review illustrates the various factors involved in the induction of B7-H1 and its role in immune evasion and chemoresistance. It also provides potential therapeutic strategies for targeting B7-H1 in breast cancer.

EXPERT OPINION

B7-H1 should be considered as a potential therapeutic target for breast cancer. Indeed, there is increasing evidence for the potential efficacy of B7-H1 blockade in the prevention of immune evasion by cancer cells. Additionally, B7-H1 targeting can be used in conjunction with other therapeutic modalities for improved efficacy and reduced toxicity. We expect that B7-H1 blockade in combination with other therapeutics will be a prime therapeutic strategy in the future.

Therapeutic effect of a peptide inhibitor of TGF-β on pulmonary fibrosis

Pulmonary fibrosis encompasses several respiratory diseases characterized by epithelial cell injury, inflammation and fibrosis. Transforming growth factor (TGF)-β1 is one of the main profibrogenic cytokines involved in the pathogenesis of lung fibrosis. It induces fibroblast differentiation into myofibroblasts, which produce high levels of collagen and concomitantly loss of lung elasticity and reduction of the respiratory function. In the present study, we have investigated the effects of P17 (a TGF-β inhibitor peptide) on IMR-90 lung fibroblast differentiation in vitro, as well as on the inhibition of the development of bleomycin-induced pulmonary fibrosis in mice. It was found that in IMR-90 cells, P17 inhibited TGF-β1-induced expression of connective tissue growth factor and α-smooth muscle actin. In vivo, treatment of mice with P17 2days after bleomycin administration decreased lung fibrosis, areas of myofibroblast-like cells and lymphocyte infiltrate. P17 also reduced mRNA expression of collagen type I, fibronectin and the fibronectin splice isoform EDA in the lung, and increased the expression of IFN-γ mRNA. Finally, therapeutic treatment with P17 in mice with already established fibrosis was able to significantly attenuate the progression of lung fibrosis. These results suggest that P17 may be useful in the treatment of pulmonary fibrosis.

Tumor-infiltrating lymphocytes and hepatocellular carcinoma: pathology and clinical management

The presence of tumor-infiltrating lymphocytes (TILs) in hepatocellular carcinoma (HCC) is relatively rare. The prognosis of patients with HCC and marked TILs is better than that of patients with HCC without TILs. TILs in HCC tissues are mainly T cells, and previous reports suggested that TILs might be important antitumor effector cells. TILs have been extensively analyzed, and subpopulations of CD3(+), CD4(+), and CD8(+) T cells are often present in HCC. Some studies have reported that the percentage of CD8(+) T cells, which might have cytotoxic activity, is decreased in tumors with TILs, as compared with noncancerous tissues. Although the antitumor effects of TILs seem to be impaired in HCCs, the underlying mechanism has remained unclear until quite recently. Pathological and in vitro studies have now shown that regulatory T cells play important roles in the deterioration of the antitumor effects of TILs. The aim of this review is to introduce recent pathological findings for TILs in HCC and to evaluate new therapeutic strategies in this field.

Tumor therapy in mice by using a tumor antigen linked to modulin peptides from Staphylococcus epidermidis

Staphylococcus epidermidis releases a complex of at least four peptides, termed phenol-soluble modulins (PSM), which stimulate macrophages to produce proinflammatory cytokines via activation of TLR2 signalling pathway. We demonstrated that covalent linkage of PSM peptides to an antigen facilitate its capture by dendritic cells and, in combination with different TLR ligands, can favour the in vivo induction of strong and persistent antigen-specific immune responses. Treatment of mice grafted with HPV16-E7-expressing tumor cells (TC-1) with poly(I:C) and a peptide containing αMod linked to the H-2D(b)-restricted cytotoxic T-cell epitope E7(49-57) from HPV16-E7 protein allowed complete tumor regression in 100% of the animals. Surprisingly, this immunomodulatory property of modulin-derived peptides was TLR2 independent and partially dependent upon the EGF-receptor signalling pathway. Our results suggest that alpha or gamma modulin peptides may serve as a suitable antigen carrier for the development of anti-tumoral or anti-viral vaccines.

Dendritic cells, indoleamine 2,3 dioxygenase and acquired immune privilege

Dendritic cells (DCs) are specialized to stimulate T cell immunity. Paradoxically, some DCs suppress T cell responses and activate regulatory T cells. In this review, we focus on a potent counter-regulatory pathway mediated by plasmacytoid DCs (pDCs) expressing the immunosuppressive enzyme indoleamine 2,3 dioxygenase (IDO). IDO-expressing pDCs inhibit effector T cell responses, activate regulatory T cells, and attenuate pro-inflammatory responses in settings of chronic inflammation that manifest in clinical syndromes, such as infectious, allergic, and autoimmune diseases; cancer; and transplantation. Thus, IDO-expressing pDCs create immune privilege and provide novel opportunities to improve immunotherapy in multiple disease syndromes.