Emerging immune checkpoints for cancer therapy

Helicobacter pylori triggers inflammation and oncogenic transformation by perturbing the immune microenvironment

The immune microenvironment plays a critical regulatory role in the pathogenesis of Helicobacter pylori (H. pylori). Understanding the mechanisms that drive the transition from chronic inflammation to cancer may provide new insights for early detection of gastric cancer. Although chronic inflammation is frequent in precancerous gastric conditions, the monitoring function of the inflammatory microenvironment in the progression from H. pylori-induced chronic inflammation to gastric cancer remains unclear. This literature review summarizes significant findings on how H. pylori triggers inflammatory responses and facilitates cancer development through the immune microenvironment. Furthermore, the implications for future research and clinical applications are also addressed. The review is divided into four main sections: inflammatory response and immune evasion mechanisms induced by H. pylori, immune dysregulation associated with gastric cancer, therapeutic implications, and future perspectives on H. pylori-induced gastric carcinogenesis with a focus on the immune microenvironment.

Molecular cytometry for comprehensive immune profiling

Molecular cytometry refers to a group of high-parameter technologies for single-cell analysis that share the following traits: (1) combined (multimodal) measurement of protein and transcripts, (2) medium throughput (10-100K cells), and (3) the use of oligonucleotide-tagged antibodies to detect protein expression. The platform can measure over 100 proteins and either hundreds of targeted genes or the whole transcriptome, on a cell-by-cell basis. It is currently one of the most powerful technologies available for immune monitoring. Here, we describe the technology platform (which includes CITE-Seq, REAP-Seq, and AbSeq), provide guidance for its optimization, and discuss advantages and limitations. Finally, we provide some vignettes from studies that demonstrate the application and potential insight that can be gained from molecular cytometry studies.

Peripheral blood CD3+HLADR+ cells and associated gut microbiome species predict response and overall survival to immune checkpoint blockade

Background

The search for biomarkers to identify ideal candidates for immune checkpoint inhibitor (ICI) therapy is fundamental. In this study, we analyze peripheral blood CD3+HLADR+ cells (activated T-cells) as a novel biomarker for ICI therapy and how its association to certain gut microbiome species can indicate individual treatment outcomes.

Methods

Flow cytometry analysis of peripheral mononuclear blood cells (PBMCs) was performed on n=70 patients undergoing ICI therapy for solid malignancies to quantify HLA-DR on circulating CD3+ cells. 16s-rRNA sequencing of stool samples was performed on n=37 patients to assess relative abundance of gut microbiota.

Results

Patients with a higher frequency of CD3+HLADR+ cells before treatment initiation showed a significantly reduced tumor response and overall survival (OS), a worst response and experienced less toxicities to ICI therapy. As such, patients with a frequency of CD3+HLADR+ cells above an ideal cut-off value of 18.55% had a median OS of only 132 days compared to 569 days for patients below. Patients with increasing CD3+HLADR+ cell counts during therapy had a significantly improved OS. An immune signature score comprising CD3+HLADR+ cells and the neutrophil-lymphocyte ratio (NLR) was highly significant for predicting OS before and during therapy. When allied to the relative abundance of microbiota from the Burkholderiales order and the species Bacteroides vulgatus, two immune-microbial scores revealed a promising predictive and prognostic power.

Conclusion

We identify the frequencies and dynamics of CD3+HLADR+ cells as an easily accessible prognostic marker to predict outcome to ICIs, and how these could be associated with immune modulating microbiome species. Two unprecedented immune-microbial scores comprising CD3+HLADR+, NLR and relative abundance of gut bacteria from the Burkhorderiales order or Bacteroides vulgatus species could accurately predict OS to immune checkpoint blockade.

Immunotherapy of thymic epithelial tumors: molecular understandings and clinical perspectives

Immunotherapy has emerged to play a rapidly expanding role in the treatment of cancers. Currently, many clinical trials of therapeutic agents are on ongoing with majority of immune checkpoint inhibitors (ICIs) especially programmed death receptor 1 (PD-1) and its ligand 1 (PD-L1) inhibitors. PD-1 and PD-L1, two main immune checkpoints, are expressed at high levels in thymic epithelial tumors (TETs) and could be predictors of the progression and immunotherapeutic efficacy of TETs. However, despite inspiring efficacy reported in clinical trials and clinical practice, significantly higher incidence of immune-related adverse events (irAEs) than other tumors bring challenges to the administration of ICIs in TETs. To develop safe and effective immunotherapeutic patterns in TETs, understanding the clinical properties of patients, the cellular and molecular mechanisms of immunotherapy and irAEs occurrence are crucial. In this review, the progress of both basic and clinical research on immune checkpoints in TETs, the evidence of therapeutic efficacy and irAEs based on PD-1 /PD-L1 inhibitors in TETs treatment are discussed. Additionally, we highlighted the possible mechanisms underlying irAEs, prevention and management strategies, the insufficiency of current research and some worthy research insights. High PD-1/PD-L1 expression in TETs provides a rationale for ICI use. Completed clinical trials have shown an encouraging efficacy of ICIs, despite the high rate of irAEs. A deeper mechanism understanding at molecular level how ICIs function in TETs and why irAEs occur will help maximize the immunotherapeutic efficacy while minimizing irAEs risks in TET treatment to improve patient prognosis.

The Role of Different Immunocompetent Cell Populations in the Pathogenesis of Head and Neck Cancer-Regulatory Mechanisms of Pro- and Anti-Cancer Activity and Their Impact on Immunotherapy

Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive and heterogeneous groups of human neoplasms. HNSCC is characterized by high morbidity, accounting for 3% of all cancers, and high mortality with ~1.5% of all cancer deaths. It was the most common cancer worldwide in 2020, according to the latest GLOBOCAN data, representing the seventh most prevalent human malignancy. Despite great advances in surgical techniques and the application of modern combinations and cytotoxic therapies, HNSCC remains a leading cause of death worldwide with a low overall survival rate not exceeding 40-60% of the patient population. The most common causes of death in patients are its frequent nodal metastases and local neoplastic recurrences, as well as the relatively low response to treatment and severe drug resistance. Much evidence suggests that the tumour microenvironment (TME), tumour infiltrating lymphocytes (TILs) and circulating various subpopulations of immunocompetent cells, such regulatory T cells (CD4+CD25+Foxp3+Tregs), cytotoxic CD3+CD8+ T cells (CTLs) and CD3+CD4+ T helper type 1/2/9/17 (Th1/Th2/Th9/Th17) lymphocytes, T follicular helper cells (Tfh) and CD56dim/CD16bright activated natural killer cells (NK), carcinoma-associated fibroblasts (CAFs), myeloid-derived suppressor cells (MDSCs), tumour-associated neutrophils (N1/N2 TANs), as well as tumour-associated macrophages (M1/M2 phenotype TAMs) can affect initiation, progression and spread of HNSCC and determine the response to immunotherapy. Rapid advances in the field of immuno-oncology and the constantly growing knowledge of the immunosuppressive mechanisms and effects of tumour cancer have allowed for the use of effective and personalized immunotherapy as a first-line therapeutic procedure or an essential component of a combination therapy for primary, relapsed and metastatic HNSCC. This review presents the latest reports and molecular studies regarding the anti-tumour role of selected subpopulations of immunocompetent cells in the pathogenesis of HNSCC, including HPV+ve (HPV+) and HPV-ve (HPV-) tumours. The article focuses on the crucial regulatory mechanisms of pro- and anti-tumour activity, key genetic or epigenetic changes that favour tumour immune escape, and the strategies that the tumour employs to avoid recognition by immunocompetent cells, as well as resistance mechanisms to T and NK cell-based immunotherapy in HNSCC. The present review also provides an overview of the pre- and clinical early trials (I/II phase) and phase-III clinical trials published in this arena, which highlight the unprecedented effectiveness and limitations of immunotherapy in HNSCC, and the emerging issues facing the field of HNSCC immuno-oncology.

Epigenetic Perspective of Immunotherapy for Cancers

Immunotherapy has brought new hope for cancer patients in recent times. However, despite the promising success of immunotherapy, there is still a need to address major challenges including heterogeneity in response among patients, the reoccurrence of the disease, and iRAEs (immune-related adverse effects). The first critical step towards solving these issues is understanding the epigenomic events that play a significant role in the regulation of specific biomolecules in the context of the immune population present in the tumor immune microenvironment (TIME) during various treatments and responses. A prominent advantage of this step is that it would enable researchers to harness the reversibility of epigenetic modifications for their druggability. Therefore, we reviewed the crucial studies in which varying epigenomic events were captured with immuno-oncology set-ups. Finally, we discuss the therapeutic possibilities of their utilization for the betterment of immunotherapy in terms of diagnosis, progression, and cure for cancer patients.

Combining a nanoparticle-mediated immunoradiotherapy with dual blockade of LAG3 and TIGIT improves the treatment efficacy in anti-PD1 resistant lung cancer

BACKGROUND

While improvements in immunoradiotherapy have significantly improved outcomes for cancer patients, this treatment approach has nevertheless proven ineffective at controlling the majority of malignancies. One of the mechanisms of resistance to immunoradiotherapy is that immune cells may be suppressed via the myriad of different immune checkpoint receptors. Therefore, simultaneous blockade of multiple immune checkpoint receptors may enhance the treatment efficacy of immunoradiotherapy.

METHODS

We combined NBTXR3-enhanced localized radiation with the simultaneous blockade of three different checkpoint receptors: PD1, LAG3, and TIGIT, and tested the treatment efficacy in an anti-PD1-resistant lung cancer model in mice. 129 Sv/Ev mice were inoculated with fifty thousand αPD1-resistant 344SQR cells in the right leg on day 0 to establish primary tumors and with the same number of cells in the left leg on day 4 to establish the secondary tumors. NBTXR3 was intratumorally injected into the primary tumors on day 7, which were irradiated with 12 Gy on days 8, 9, and 10. Anti-PD1 (200 µg), αLAG3 (200 µg), and αTIGIT (200 µg) were given to mice by intraperitoneal injections on days 5, 8, 11, 14, 21, 28, 35, and 42.

RESULTS

This nanoparticle-mediated combination therapy is effective at controlling the growth of irradiated and distant unirradiated tumors, enhancing animal survival, and is the only one that led to the destruction of both tumors in approximately 30% of the treated mice. Corresponding with this improved response is robust activation of the immune response, as manifested by increased numbers of immune cells along with a transcriptional signature of both innate and adaptive immunity within the tumor. Furthermore, mice treated with this combinatorial therapy display immunological memory response when rechallenged by the same cancer cells, preventing tumor engraftment.

CONCLUSION

Our results strongly attest to the efficacy and validity of combining nanoparticle-enhanced radiotherapy and simultaneous blockade of multiple immune checkpoint receptors and provide a pre-clinical rationale for investigating its translation into human patients.

Analysis of the immune checkpoint lymphocyte activation gene-3 (LAG-3) in endometrial cancer: An emerging target for immunotherapy

BACKGROUND

Lymphocyte activation gene-3 (LAG-3) is a novel molecule that participates in the immune escape of tumor cells and is a target for immunotherapy. However, the expression of LAG-3 in patients with endometrial cancer (EC) has not been comprehensively characterized.

OBJECTIVES

We elucidated the expression of LAG-3 and investigated its correlation with clinicopathological parameters, ProMisE subtypes, CD8⁺ T-cell infiltration and relapse-free survival (RFS) in a retrospective cohort of 421 patients with endometrial cancer.

METHODS

Next-generation sequencing of the polymerase epsilon (POLE) and immunohistochemistry of mismatch repair (MMR)-related protein (MLH1, PMS2, MSH2, and MSH6), p53, CD8 and LAG-3 protein in whole sections were performed.

RESULTS

Positive LAG-3 was detected in tumor cells (TCs) and immune cells (ICs) in 31.6% (133/421) and 24.0% (101/421) of the patients, respectively. LAG-3 positivity in ICs was more common in high-grade, high-intermediate risk, high-risk, and advanced/metastatic subgroups and was relevant to lymphovascular space invasion, while that in TCs was more common in older individuals (≥54 years). LAG-3 expression was more prevalent in POLE ultramutated (POLEmut) and MMR-deficient (MMRd) EC than in p53-abnormal (p53abn) and p53-wild (p53wt) EC in TCs (34.4 % and 66.3% in POLEmut and MMRd versus 28.6% and 19.5% in p53abn and p53wt, P < 0.001) and ICs (78.1 % and 65.1% in POLEmut and MMRd versus 2.9% and 5.2% in p53abn and p53wt, P < 0.001). Positive expression of LAG-3 in TCs and ICs was associated with high levels of tumor-associated CD8⁺ T-cell immune infiltration. Additionally, LAG-3 positivity in TCs was related to improved RFS.

CONCLUSIONS

This study suggests that immunotherapy targeting LAG-3 may play a role in EC patients with POLEmut or MMRd molecular markers. Positive LAG-3 expression in TCs may be a predictor of improved RFS.

LRMP Associates With Immune Infiltrates and Acts as a Prognostic Biomarker in Lung Adenocarcinoma

Background: Lymphoid-restricted membrane protein (LRMP) is an endoplasmic reticulum-associated protein that is expressed in a developmentally regulated manner in both B and T cell lineages. However, the role of LRMP in the growth, prognosis and immune infiltration in lung adenocarcinoma (LUAD) remains unclear.

Method: The expression levels of LRMP mRNA in tumor and normal tissues were analyzed using Tumor Immune Estimation Resource 2.0 (TIMER 2.0) and Gene Expression Profiling Interactive Analysis 2 (GEPIA 2). LRMP protein expression was examined using the Human Protein Atlas. In vitro experiments, including qRT-PCR Western blot and immunohistochemistry staining were also performed to investigate LRMP expression. GEPIA2 and Kaplan-Meier plotter databases were used to analyze the clinical prognostic significance of LRMP. To further confirm the underlying function of LRMP, the data were analyzed using gene set enrichment analysis. Moreover, we also constructed plasmids to overexpress LRMP and explored the effect of LRMP in A549 cell line. Additionally, Tumor Immune single-cell Hub was used to investigate the distribution of LRMP in the LUAD immune microenvironment; TIMER and CIBERSORT were used to investigate the relationships among LRMP, LRMP co-expressed genes, and tumor-infiltrating immune cells; Finally, the correlations between LRMP and immune checkpoints were analyzed using TIMER 2.0.

Results: The expression of LRMP was significantly lower in LUAD tissues and cell lines. High LRMP expression is associated with a better prognosis in patients with LUAD. In vitro experimental studies demonstrated that overexpression of LRMP could decrease the proliferation, migration and invasion in A549 cells, and downregulated multiple oncogenic signaling pathways, including p-STAT3, p-PI3K-p-AKT, p-MEK and EMT pathways. GSEA results showed that immuno-related and cell adhesion pathways were enriched in samples with high LRMP expression. LRMP and its co-expressed genes were positively correlated with various tumor-infiltrating immune cells and their markers. Additionally, LRMP positively correlated with immune checkpoints.

Conclusions: Our data suggest that LRMP may act as a tumor suppressor gene and indicates a better prognosis. Moreover, LRMP is associated with immune infiltrates which may be involved in immunotherapy response in LUAD. Further studies are needed to validate these findings.

Response to radiotherapy in pancreatic ductal adenocarcinoma is enhanced by inhibition of myeloid-derived suppressor cells using STAT3 anti-sense oligonucleotide

Pancreatic ductal adenocarcinoma (PDAC) has a heterogeneous tumor microenvironment (TME) comprised of myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages, neutrophils, regulatory T cells, and myofibroblasts. The precise mechanisms that regulate the composition of the TME and how they contribute to radiotherapy (RT) response remain poorly understood. In this study, we analyze changes in immune cell populations and circulating chemokines in patient samples and animal models of pancreatic cancer to characterize the immune response to radiotherapy. Further, we identify STAT3 as a key mediator of immunosuppression post-RT. We found granulocytic MDSCs (G-MDSCs) and neutrophils to be increased in response to RT in murine and human PDAC samples. We also found that RT-induced STAT3 phosphorylation correlated with increased MDSC infiltration and proliferation. Targeting STAT3 using an anti-sense oligonucleotide in combination with RT circumvented RT-induced MDSC infiltration, enhanced the proportion of effector T cells, and improved response to RT. In addition, STAT3 inhibition contributed to the remodeling of the PDAC extracellular matrix when combined with RT, resulting in decreased collagen deposition and fibrotic tissue formation. Collectively, our data provide evidence that targeting STAT3 in combination with RT can mitigate the pro-tumorigenic effects of RT and improve tumor response.

Ferroptosis: a new unexpected chance to treat metastatic melanoma?

Human skin melanoma is one of the most aggressive and difficult to treat human malignancies, with an increasing incidence over the years. While the resection of the early diagnosed primary tumor remains the best clinical approach, advanced/metastatic melanoma still remains with a poor prognosis. Indeed, although enormous progress in the therapeutic treatment of human tumors has been made in recent years, patients affected by metastatic melanoma are still poorly affected by these clinical advances. Therefore, new valuable therapeutic approaches are urgently needed, to design and define effective treatments to consistently increase the overall survival rate of patients affected by this malignancy. In this review we summarize the main signaling pathways studied to kill human skin melanoma, and introduce the ferroptotic cell death as a new pathway to be explored to eradicate this tumor.

Manipulation of the Immune System for Cancer Defeat: A Focus on the T Cell Inhibitory Checkpoint Molecules

The immune system actively counteracts the tumorigenesis process; a breakout of the immune system function, or its ability to recognize transformed cells, can favor cancer development. Cancer becomes able to escape from immune system control by using multiple mechanisms, which are only in part known at a cellular and molecular level. Among these mechanisms, in the last decade, the role played by the so-called "inhibitory immune checkpoints" is emerging as pivotal in preventing the tumor attack by the immune system. Physiologically, the inhibitory immune checkpoints work to maintain the self-tolerance and attenuate the tissue injury caused by pathogenic infections. Cancer cell exploits such immune-inhibitory molecules to contrast the immune intervention and induce tumor tolerance. Molecular agents that target these checkpoints represent the new frontier for cancer treatment. Despite the heterogeneity and multiplicity of molecular alterations among the tumors, the immune checkpoint targeted therapy has been shown to be helpful in selected and even histologically different types of cancer, and are currently being adopted against an increasing variety of tumors. The most frequently used is the moAb-based immunotherapy that targets the Programmed Cell Death 1 protein (PD-1), the PD-1 Ligand (PD-L1) or the cytotoxic T lymphocyte antigen-4 (CTLA4). However, new therapeutic approaches are currently in development, along with the discovery of new immune checkpoints exploited by the cancer cell. This article aims to review the inhibitory checkpoints, which are known up to now, along with the mechanisms of cancer immunoediting. An outline of the immune checkpoint targeting approaches, also including combined immunotherapies and the existing trials, is also provided. Notwithstanding the great efforts devoted by researchers in the field of biomarkers of response, to date, no validated FDA-approved immunological biomarkers exist for cancer patients. We highlight relevant studies on predictive biomarkers and attempt to discuss the challenges in this field, due to the complex and largely unknown dynamic mechanisms that drive the tumor immune tolerance.

SUV39H1-DNMT3A-mediated epigenetic regulation of Tim-3 and galectin-9 in the cervical cancer

Background

Methylation of histone 3 at lysine 9 (H3K9) and DNA methylation are epigenetic marks correlated with genes silencing. The tumor microenvironment significantly influences therapeutic responses and clinical outcomes. The epigenetic-regulation mechanism of the costimulatory factors Tim-3 and galectin-9 in cervical cancer remains unknown.

Methods

The methylation status of HAVCR2 and LGALS9 were detected by MS-PCR in cervical cancer tissues and cell lines. The underlying molecular mechanism of SUV39H1-DNMT3A-Tim-3/galectin-9 regulation was elucidated using cervical cancer cell lines containing siRNA or/and over-expression system. Confirmation of the regulation of DNMT3A by SUV39H1 used ChIP-qPCR.

Results

SUV39H1 up-regulates H3K9me3 expression at the DNMT3A promoter region, which in turn induced expression of DNMT3A in cervical cancer. In addition, the mechanistic studies indicate that DNMT3A mediates the epigenetic modulation of the HAVCR2 and LGALS9 genes by directly binding to their promoter regions in vitro. Moreover, in an in vivo assay, the expression profile of SUV39H1 up-regulates the level of H3K9me3 at the DNMT3A promoter region was found to correlate with Tim-3 and galectin-9 cellular expression level.

Conclusion

These results indicate that SUV39H1-DNMT3A is a crucial Tim-3 and galectin-9 regulatory axis in cervical cancer.

Looking past PD-L1: expression of immune checkpoint TIM-3 and its ligand galectin-9 in cervical and vulvar squamous neoplasia

Immunotherapies targeting the PD-1/PD-L1 pathway have shown some success in cervical and vulvar squamous cell carcinomas, but little is known about the potential vulnerability of these tumors to other checkpoint inhibitors. TIM-3 is a checkpoint molecule that exerts immunosuppressive function via its interaction with Gal-9. TIM-3 and Gal-9 have been identified on a variety of malignancies but have not been studied in cervical and vulvar cancers, nor has their relationship to PD-L1 been established. Sixty-three cervical and vulvar invasive (n = 34) and intraepithelial lesions (n = 29) were assessed for TIM-3, Gal-9, and PD-L1 in tumor/lesional cells and associated immune cells. Tumoral TIM-3 expression was identified in 85% of squamous cell carcinomas but only 21% of intraepithelial lesions (p < 0.0001). When immune cells were also accounted for, 97% of invasive and 41% of intraepithelial lesions had a TIM-3 combined positive score (CPS) ≥ 1 (p < 0.0001). Tumoral membranous expression of Gal-9 was seen in 82% of squamous cell carcinomas and 31% of intraepithelial lesions (p = 0.0001); nearly all cases had Gal-9-positive immune cells. Tumoral PD-L1 was seen in 71% of squamous cell carcinomas and 10% of intraepithelial lesions (p < 0.0001), while the PD-L1 CPS was ≥1 in 82 and 21%, respectively (p < 0.0001). There were no significant differences in TIM-3, GAL-9, or PD-L1 expression in cervical vs. vulvar neoplasms, nor was HPV status significantly associated with any of the three markers. Dual TIM-3/Gal-9 expression was present in the majority (86%) of PD-L1-positive cases including 100% of PD-L1-positive squamous cell carcinomas, suggesting a possible role for TIM-3 checkpoint inhibition in concert with anti-PD-1/PD-L1.

Crosstalk between histone modification and DNA methylation orchestrates the epigenetic regulation of the costimulatory factors, Tim‑3 and galectin‑9, in cervical cancer

Persistent infection with high-risk human papillomavirus is known to cause cervical cancer. The binding of the costimulatory factors, Tim-3 and galectin-9, can cause immune tolerance and lead to immune escape during carcinogenesis. Epigenetic regulation is essential for Tim-3/galectin-9 expression, which affects the outcome of local cervical cancer infection. Hence, exploring the epigenetic regulatory mechanisms of costimulatory signaling by Tim-3/galectin-9 is of great interest for investigating the mechanisms through which these proteins are regulated in cervical cancer tumorigenesis. In this study, we report that E2F-1 and FOXM1 mediated by HPV18 E6 and E7 can enhance the transcriptional activity of Enhancer of zeste homolog 2 (EZH2) by binding to its promoter region, resulting in the induced expression of the EZH2-specific target protein, H3K27me3, which consequently reduces the expression of the downstream target gene, DNA (cytosine-5)-methyltransferase 3A (DNMT3A). EZH2 and H3K27me3 directly interact with the DNMT3A promoter region to negatively regulate its expression in HeLa cells. Moreover, the downregulated DNMT3A and the decreased methylation levels in HAVCR2/LGALS9 promoter regions in HeLa cells promoted the expression of Tim-3/galectin-9. Furthermore, the high expression of Tim-3/galectin-9 was associated with HPV positivity among patients with cervical cancer. Moreover, HAVCR2/LGALS9 promoter regions were hypermethylated in normal cervical tissues, and this hypermethylated status inhibited gene expression. On the whole, these findings suggest that EZH2, H3K27me3 and DNMT3A mediate the epigenetic regulation of the negative stimulatory molecules, Tim-3 and galectin-9 in cervical cancer which is associated with HPV18 infection.

Management of Adverse Events in Cancer Patients Treated With PD-1/PD-L1 Blockade: Focus on Asian Populations

The interaction between programmed cell death protein 1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1) induces exhaustions of cytotoxic lymphocytes in the tumor microenvironment, which facilitates tumor immune evasion. PD-1/PD-L1 blockade therapy, which prevents the receptors and ligands from binding to each other, disrupts the T-cell exhaustion signaling, thereby increasing antitumor immunity. Inspiringly, it has revolutionized the treatment of many different types of cancers including non-small-cell lung carcinoma, melanoma, lymphoma, and so on. However, with the intention of generating an antitumor immune response, PD-1/PD-L1 blockade may also lead to a spectrum of side effects. The profile of adverse events (AEs) of PD-1/PD-L1 blockade is not exactly the same with other immune checkpoint blockades, such as blockade of cytotoxic T-lymphocyte-associated protein 4. Although cutaneous, gastrointestinal, and pulmonary systems are common victims, AEs of PD-1/PD-L1 blockade might occur in any other organ system of the human body. These toxicities can be life-threatening if not managed promptly, and proper treatment intervention is imperative for optimal control and prevention of severe damage. Currently, clinical practice for the management of AEs in PD-1/PD-L1 blockade remains sporadic and variable. The majority of initial clinical trials were carried out in Caucasians. The trials of multiple races usually included a small portion of Asian participants, and results were calculated and interpreted for the entire included subjects without any race-specific conclusions. Therefore, the information on PD-1/PD-L1 blockade in Asians is far from systematic or comprehensive. Recently, as the results of clinical trials of anti-PD-1/PD-L1 agents in Asian populations have been gradually released, we summarized current evidence with a specific focus on the Asian population, hoping to outline strategies and offer guidance on the management of AEs in cancer patients treated with PD-1/PD-L1 blockade in the Asian world.

TIM-3 in endometrial carcinomas: an immunotherapeutic target expressed by mismatch repair-deficient and intact cancers

The checkpoint molecule TIM-3 is a target for emerging immunotherapies and has been identified on a variety of malignancies. Mismatch repair-deficient endometrial carcinomas have demonstrated durable responses to other checkpoint inhibitors due to high neoantigen loads and robust tumor-associated immune responses. However, little is known about TIM-3 expression in this tumor type. Tumor-associated immune and tumoral expression of TIM-3 were evaluated by immunohistochemistry on 75 endometrial carcinomas [25 MLH1 promoter hypermethylated (MLH1-hypermethylated), 25 non-hypermethylated mismatch repair-deficient, and 25 mismatch repair-intact]. All cases showed at least focal immune staining, but moderate and robust immune cell expression were more often observed in mismatch repair-deficient vs intact cases [66 vs 12%, P = 0.00002]. While the majority (77%) of endometrial cancers showed ≥1% tumoral TIM-3 expression, the MLH1-hypermethylated subset was more likely to demonstrate >5% tumoral staining when compared to both mismatch repair-intact and non-methylated mismatch repair-deficient cancers [64 vs. 28% and 32%, respectively; P = 0.02 and P = 0.05]. Within the non-methylated mismatch repair-deficient subset, high-level expression was most often associated with MSH6 loss. Across mismatch repair subgroups, tumoral TIM-3 expression was more common among intermediate and high-grade vs. low-grade tumors using both the 1% (P = 0.02) and 5% expression cut-offs (P = 0.02). In conclusion, tumoral TIM-3 expression is common in both mismatch repair-intact and deficient endometrial cancers, with particularly high levels of expression identified in the setting of MLH1-hypermethylation, MSH6 loss, and intermediate to high histologic grade. Although focal immune cell expression was seen in all tumors, robust expression was significantly more common in the context of mismatch repair deficiency. These data support a potential role for checkpoint inhibitors targeting TIM-3 in a subset of endometrial cancers, including some mismatch repair-intact tumors which are not currently considered immunotherapy candidates.

Pancreatic Tumor Microenvironment Modulation by EphB4-ephrinB2 Inhibition and Radiation Combination

PURPOSE

A driving factor in pancreatic ductal adenocarcinoma (PDAC) treatment resistance is the tumor microenvironment, which is highly immunosuppressive. One potent immunologic adjuvant is radiotherapy. Radiation, however, has also been shown to induce immunosuppressive factors, which can contribute to tumor progression and formation of fibrotic tumor stroma. To capitalize on the immunogenic effects of radiation and obtain a durable tumor response, radiation must be rationally combined with targeted therapies to mitigate the influx of immunosuppressive cells and fibrosis. One such target is ephrinB2, which is overexpressed in PDAC and correlates negatively with prognosis.Experimental Design: On the basis of previous studies of ephrinB2 ligand-EphB4 receptor signaling, we hypothesized that inhibition of ephrinB2-EphB4 combined with radiation can regulate the microenvironment response postradiation, leading to increased tumor control in PDAC. This hypothesis was explored using both cell lines and in vivo human and mouse tumor models.

RESULTS

Our data show this treatment regimen significantly reduces regulatory T-cell, macrophage, and neutrophil infiltration and stromal fibrosis, enhances effector T-cell activation, and decreases tumor growth. Furthermore, our data show that depletion of regulatory T cells in combination with radiation reduces tumor growth and fibrosis.

CONCLUSIONS

These are the first findings to suggest that in PDAC, ephrinB2-EphB4 interaction has a profibrotic, protumorigenic role, presenting a novel and promising therapeutic target.

Rationale for combination of radiation therapy and immune checkpoint blockers to improve cancer treatment

Radiation therapy for cancer is considered to be immunosuppressive. However, the cellular response after radiation therapy may stimulate or suppress an immune response. The effect may vary with the tumor type and occasionally tumor regressions have been observed outside the irradiated volume, both in animal studies and in the clinic. A renewed interest in the role of immunity for the observed effect of radiation came with the current recognized role of immune checkpoint blockers (ICBs) for control of selected cancer types. We therefore here review preclinical studies and clinical reports on the interaction of ICBs and radiation as a basis for further clinical trials. Some tumor types where the combination of these modalities seems especially promising are also proposed.

From Friend to Enemy: Dissecting the Functional Alteration of Immunoregulatory Components during Pancreatic Tumorigenesis

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease with a 5-year survival rate of approximately 8%. More than 80% of patients are diagnosed at an unresectable stage due to metastases or local extension. Immune system reactivation in patients by immunotherapy may eliminate tumor cells and is a new strategy for cancer treatment. The anti-CTLA-4 antibody ipilimumab and anti-PD-1 antibodies pembrolizumab and nivolumab have been approved for cancer therapy in different countries. However, the results of immunotherapy on PDAC are unsatisfactory. The low response rate may be due to poor immunogenicity with low tumor mutational burden in pancreatic cancer cells and desmoplasia that prevents the accumulation of immune cells in tumors. The immunosuppressive tumor microenvironment in PDAC is important in tumor progression and treatment resistance. Switching from an immune tolerance to immune activation status is crucial to overcome the inability of self-defense in cancer. Therefore, thoroughly elucidation of the roles of various immune-related factors, tumor microenvironment, and tumor cells in the development of PDAC may provide appropriate direction to target inflammatory pathway activation as a new therapeutic strategy for preventing and treating this cancer.

Clinicopathological analysis of PD-L2 expression in colorectal cancer

Background

(PD-L2), a ligand of programmed cell death protein 1 (PD-1), is an inhibitory receptor of T cells and activated B cells. Many studies have focused on PD-L1, another ligand of PD-1, and the prognostic significance of PD-L1 has been reported in many tumors. However, the expression of PD-L2 in relation to clinical outcomes has not been fully investigated in cancer patients.

Patients and methods

In this study, we investigated the expression of PD-L2 via immunohistochemistry (IHC) in the pathological specimens of 348 patients treated for colorectal cancer (CRC).

Results

Strong PD-L2 expression was found in the cancer tissues from 41% of the CRC patients who also had a high TNM stage and carcinoembryonic antigen (CEA) concentration. We also carried out functional studies in vitro, which showed that PD-L2 did not influence the growth of the CRC cell line HCT116, but increased cell invasion.

Conclusion

Collectively, these findings suggest that PD-L2 may be a potential therapeutic target for CRC.

The Central Role of Inflammation Associated with Checkpoint Inhibitor Treatments

An important function of the immune system is its ability to differentiate between healthy cells in the organism and "foreign" cells, allowing the latest to be attacked and the first ones to be conserved. The most important molecules in this process are considered to be checkpoint inhibitors. This review is focused on the association between cancer and inflammation, underlying the mechanisms of action of monoclonal antibodies that are targeting checkpoint inhibitors: ipilimumab against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and pembrolizumab and nivolumab against programmed cell death protein 1 (PD-1), their indications for treatment, and side effects. Presence of antibodies against checkpoint inhibitors shows promising results in the clinical trials in patients with types of cancer difficult to treat until now such as melanoma, non-small-cell lung cancer (NSCLC), and renal cell carcinoma, offering an increase in the overall survival rate, response rate, and progression-free rate. Resistance is now observed to emerge in patients treated with this therapy, showing the need for more studies in order to design a biomarker that will predict the type of response to immunotherapy.

Checkpoints and beyond - Immunotherapy in colorectal cancer

Immunotherapy is the latest revolution in cancer therapy. It continues to show impressive results in malignancies like melanoma and others. At least so far, effects are modest in colorectal cancer (CRC) and only a subset of patients benefits from already approved checkpoint inhibitors. In this review, we discuss major hurdles of immunotherapy like the immunosuppressive niche and low immunogenicity of CRC next to current achievements of checkpoint inhibitors, interleukin treatment and adoptive cell transfer (dendritic cells/cytokine induced killer cells, tumor infiltrating lymphocytes, chimeric antigen receptor cells, T cell receptor transfer) in pre-clinical models and clinical trials. We intensively examine approaches to overcome low immunogenicity by combination of different therapies and address future strategies of therapy as well as the need of predictive factors in this emerging field of precision medicine.

Immune Evasion in Pancreatic Cancer: From Mechanisms to Therapy

Pancreatic ductal adenocarcinoma (PDA), the most frequent type of pancreatic cancer, remains one of the most challenging problems for the biomedical and clinical fields, with abysmal survival rates and poor therapy efficiency. Desmoplasia, which is abundant in PDA, can be blamed for much of the mechanisms behind poor drug performance, as it is the main source of the cytokines and chemokines that orchestrate rapid and silent tumor progression to allow tumor cells to be isolated into an extensive fibrotic reaction, which results in inefficient drug delivery. However, since immunotherapy was proclaimed as the breakthrough of the year in 2013, the focus on the stroma of pancreatic cancer has interestingly moved from activated fibroblasts to the immune compartment, trying to understand the immunosuppressive factors that play a part in the strong immune evasion that characterizes PDA. The PDA microenvironment is highly immunosuppressive and is basically composed of T regulatory cells (Tregs), tumor-associated macrophages (TAMs), and myeloid-derived suppressive cells (MDSCs), which block CD8⁺ T-cell duties in tumor recognition and clearance. Interestingly, preclinical data have highlighted the importance of this immune evasion as the source of resistance to single checkpoint immunotherapies and cancer vaccines and point at pathways that inhibit the immune attack as a key to solve the therapy puzzle. Here, we will discuss the molecular mechanisms involved in PDA immune escape as well as the state of the art of the PDA immunotherapy.

Advances in Immunotherapy for Melanoma: A Comprehensive Review

Melanomas are tumors originating from melanocytes and tend to show early metastasis secondary to the loss of cellular adhesion in the primary tumor, resulting in high mortality rates. Cancer-specific active immunotherapy is an experimental form of treatment that stimulates the immune system to recognize antigens on the surface of cancer cells. Current experimental approaches in immunotherapy include vaccines, biochemotherapy, and the transfer of adoptive T cells and dendritic cells. Several types of vaccines, including peptide, viral, and dendritic cell vaccines, are currently under investigation for the treatment of melanoma. These treatments have the same goal as drugs that are already used to stimulate the proliferation of T lymphocytes in order to destroy tumor cells; however, immunotherapies aim to selectively attack the tumor cells of each patient. In this comprehensive review, we describe recent advancements in the development of immunotherapies for melanoma, with a specific focus on the identification of neoantigens for the prediction of their elicited immune responses. This review is expected to provide important insights into the future of immunotherapy for melanoma.

Tumor immunotherapy: drug-induced neoantigens (xenogenization) and immune checkpoint inhibitors

More than 40 years ago, we discovered that novel transplantation antigens can be induced in vivo or in vitro by treating murine leukemia with dacarbazine. Years later, this phenomenon that we called "Chemical Xenogenization" (CX) and more recently, "Drug-Induced Xenogenization" (DIX), was reproduced by Thierry Boon with a mutagenic/carcinogenic compound (i.e. N-methyl-N'-nitro-N-nitrosoguanidine). In both cases, the molecular bases of DIX rely on mutagenesis induced by methyl adducts to oxygen-6 of DNA guanine. In the present review we illustrate the main DIX-related immune-pharmacodynamic properties of triazene compounds of clinical use (i.e. dacarbazine and temozolomide).In recent years, tumor immunotherapy has come back to the stage with the discovery of immune checkpoint inhibitors (ICpI) that show an extraordinary immune-enhancing activity. Here we illustrate the salient biochemical features of some of the most interesting ICpI and the up-to-day status of their clinical use. Moreover, we illustrate the literature showing the direct relationship between somatic mutation burden and susceptibility of cancer cells to host's immune responses.When DIX was discovered, we were not able to satisfactorily exploit the possible presence of triazene-induced neoantigens in malignant cells since no device was available to adequately enhance host's immune responses in clinical settings. Today, ICpI show unprecedented efficacy in terms of survival times, especially when elevated mutation load is associated with cancer cells. Therefore, in the future, mutation-dependent neoantigens obtained by appropriate pharmacological intervention appear to disclose a novel approach for enhancing the therapeutic efficacy of ICpI in cancer patients.

PD-1 expression by canine T cells and functional effects of PD-1 blockade

The co-inhibitory checkpoint molecule programmed death receptor 1 (PD-1) can trigger T cell functional exhaustion upon binding to its ligand PD-L1 expressed on tumour cells or macrophages. PD-1 blocking antibodies have generated remarkable results in human cancer patients, including inducing durable responses in a number of advanced cancers. Therefore, monoclonal antibodies specific for canine PD-1 were assessed for T cell binding and induction of functional activation. A total of 5-10% of CD4 T cells and 20-25% of CD8 T cells from healthy dogs expressed PD-1, and PD-1 expression was upregulated on T cells from dogs with cancer. Functionally, PD-1 antibodies significantly enhanced T-cell activation, as assessed by proliferation and interferon-gamma (IFN-γ) production. PD-1 antibodies also reversed T-cell suppression induced by canine soluble PD-L1 and by tumour cells and tumour explant fragments. These findings indicate that PD-1 antibodies have potential for use in cancer immunotherapy in dogs.

Checkpoint inhibition in myeloma

Historically, attempts at cancer immunotherapy have emphasized strategies designed to stimulate or augment the immune system into action. In the past decade, a complementary approach has developed, that of releasing immune cells from inhibitory restraint. Discoveries in the fundamental biology of how immunity is regulated, how the immune system interfaces with malignancy, and how cancer cells may exploit these processes to evade detection have all been translated into the rapidly growing field of therapeutic immune checkpoint inhibition for cancer. Myeloma is a malignancy associated with significant immune dysfunction imparted both by the disease itself as well as by many of the immunosuppressive therapies that have been used in the past. The growing body of preclinical data regarding immunoregulatory mechanisms that appear active in myeloma has begun to be translated to clinical trials targeting these signaling axes. This review will attempt to summarize the current understanding of the basic biology of several immune checkpoint pathways that may be important in myeloma and provide an up-to-date overview of recent and ongoing clinical trials of immune checkpoint inhibitors in myeloma. Finally, several current challenges and possible future directions of immune checkpoint blockade in myeloma will be reviewed.

Combinatorial approach to cancer immunotherapy: strength in numbers

Immune-checkpoint blockade therapy with antibodies targeting CTLA-4 and PD-1 has revolutionized melanoma treatment by eliciting responses that can be remarkably durable and is now advancing to other malignancies. However, not all patients respond to immune-checkpoint inhibitors. Extensive preclinical evidence suggests that combining immune-checkpoint inhibitors with other anti-cancer treatments can greatly improve the therapeutic benefit. The first clinical success of the combinatorial approach to cancer immunotherapy was demonstrated using a dual-checkpoint blockade with CTLA-4 and PD-1 inhibitors, which resulted in accelerated FDA approval of this therapeutic regimen. In this review, we discuss the combinations of current and emerging immunotherapeutic agents in clinical and preclinical development and summarize the insights into potential mechanisms of synergistic anti-tumor activity gained from animal studies. These promising combinatorial partners for the immune-checkpoint blockade include therapeutics targeting additional inhibitory receptors of T cells, such as TIM-3, LAG-3, TIGIT, and BTLA, and agonists of T cell costimulatory receptors 4-1BB, OX40, and GITR, as well as agents that promote cancer cell recognition by the immune system, such as tumor vaccines, IDO inhibitors, and agonists of the CD40 receptor of APCs. We also review the therapeutic potential of regimens combining the immune-checkpoint blockade with therapeutic interventions that have been shown to enhance immunogenicity of cancer cells, including oncolytic viruses, RT, epigenetic therapy, and senescence-inducing therapy.

Immune-Related Adverse Events From Immune Checkpoint Inhibitors

Immunotherapy for cancer treatment has come of age, specifically with the use of immune checkpoint antibodies directed against molecules such as CTLA-4, PD-1, and PD-L1. Single-agent and combinatorial approaches utilizing these agents and other immunotherapies that may enhance antitumor effects are under investigation. With increasing clinical use of these agents, an appreciation for their toxicities comes to the fore. Adverse events that occur as a result of the immunologic effects of these therapies are termed "immune-related adverse events" (irAEs), and range in both frequency and severity in reported single-agent and combination studies. Improvements in our understanding of how and why irAEs develop and how to effectively manage them are needed. Herein we provide a state-of-the-art synopsis of the incidence, clinical features, mechanisms, and management of selected irAEs with immune checkpoint inhibitors currently in use.

Immune based therapy for melanoma

A few years ago therapeutic options in advanced melanoma were very limited and the prognosis was somber. Although recent progresses are far from providing a cure for advanced melanoma, yet these have kindled new hopes and searching for a cure does not seem unreasonable. Seven new medicines have been authorized in various regions of the world in the recent past in the therapy of advanced melanoma, over half of them acting by mechanisms involving the immune system of the host. The anti-CTLA-4 (cytotoxic T lymphocyte associated protein-4) ipilimumab has been followed by anti-PD1 (programmed death1) inhibitors, more effective and safer. Very recently, the first oncolytic immunotherapy, talimogene laherparepvec (T-VEC) has been authorized for placing on the market and a variety of combinations of the new therapies are currently being evaluated or considered. Besides, a plethora of other molecules and approaches, especially monoclonal antibodies, are in the preliminary phases of clinical investigation and are likely to bring new benefits for the treatment of this potentially fatal form of cancer.

5th International ACC Symposium: Future and Current Therapeutic Trials in Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare and complex disease associated with a high mortality rate. Despite intensive translational and clinical research, prognosis remains poor. Over the past decade, a significant effort has been made to develop multinational, collaborative studies to better understand the pathogenesis and clinical features of this rare disease in attempt to improve the therapeutic strategies and patient outcome. The results of both standard and newer treatments are discussed in this review as well as the recent discovery of pathways involved in ACC pathogenesis that provide the rationale to introduce new molecular target therapies. Finally, remaining issues regarding how to improve available therapies in adjuvant setting are raised and addressed.