Treg expansion with trichostatin A ameliorates kidney ischemia/reperfusion injury in mice by suppressing the expression of costimulatory molecules.

Innate immune reactions are believed to be associated with ischemia/reperfusion injury (IRI), and IRI might be treatable by expanding regulatory T cells (Tregs), which can suppress the excessive responses of the immune system. Organ IRI is known to be closely involved in the expression of costimulatory molecules. The present study aimed to assess whether Tregs endogenously expanded by the administration of trichostatin A (TsA), a histone deacetylase inhibitor, could reduce renal IRI and to clarify their association with the expression of costimulatory molecules in a murine model. In this study, the wild-type mice used for an IRI model were randomly divided into the following four treatment groups: TsA group, DMSO group (control), DMSO+PC61 group, and TsA + PC61 group. Renal injury in the early phase after IRI was ameliorated in the TsA group (increased Tregs) when compared with the other groups. After renal IRI, both the mRNA and the protein levels of anti-inflammatory cytokines, IL-10 and TGF-ß in the kidney and spleen were significantly higher in the TsA group than in the other groups, whereas the IL-6 levels were significantly lower in the TsA group than in the other groups. These results were offset by the administration of PC61, supporting that the renoprotective effect of TsA in this study is Treg dependent. mRNA expression levels of CD80, CD86, and ICAM-1 were lower in the TsA group, consistent with Treg control of injury through costimulatory molecules. Our findings suggest that endogenously expanded Tregs coordinate postischemic immune responses and decrease the expression of costimulatory molecules after renal IRI, and thus, they might ameliorate renal IRI. TsA administration for expanding Tregs is a promising therapeutic strategy for renal IRI.

Talimogene laherparepvec treatment to overcome loco-regional acquired resistance to immune checkpoint blockade in tumor stage IIIB-IV M1c melanoma patients.

BACKGROUND: Resistance to immune checkpoint blockade and targeted therapy in melanoma patients is currently one of the major clinical challenges. With the approval of talimogene laherparepvec (T-VEC), oncolytic viruses are now in clinical practice for locally advanced or non-resectable melanoma. Here, we describe the usage of T-VEC in stage IVM1b-M1c melanoma patients, who achieved complete remission or stable disease upon systemic treatment but suffered from a loco-regional recurrence. To our knowledge, there are no case reports so far describing T-VEC as a means to overcome acquired resistance to immune checkpoint blockade or targeted therapy. METHODS: All melanoma patients in our department treated with T-VEC in the period of 2016-2018 were evaluated retrospectively. Data on clinicopathological characteristics, treatment response, and toxicity were analyzed. RESULTS: Fourteen melanoma patients were treated with T-VEC in our center. Six patients (43%) received T-VEC first-line. In eight patients (57%), T-VEC followed a prior systemic therapy. Three patients with M1b stage and one patient with M1c stage melanoma were treated with T-VEC. These patients suffered from loco-regional progress, whilst distant metastases had regressed during prior systemic treatment. 64% of patients showed a benefit from therapy with T-VEC. The durable response rate was 36%. CONCLUSION: T-VEC represents an effective and tolerable treatment option. This is true not only for loco-regionally advanced melanoma patients, but also for patients with stable or regressive systemic metastases who develop loco-regionally acquired resistance upon treatment with immune checkpoint blockade or targeted therapy. A sensible selection of suitable patients seems to be crucial.

Immunological Targets for Immunotherapy: Inhibitory T Cell Receptors.

Tumor development is characterized by the accumulation of mutational and epigenetic changes that transform normal cells and survival pathways into self-sustaining cells capable of untrammeled growth. Although multiple modalities including surgery, radiation, and chemotherapy are available for the treatment of cancer, the benefits conferred are often limited. The immune system is capable of specific, durable, and adaptable responses. However, cancers hijack immune mechanisms such as negative regulatory checkpoints that have evolved to limit inflammatory and immune responses to thwart effective antitumor immunity. The development of monoclonal antibodies against inhibitory receptors expressed by immune cells has produced durable responses in a broad array of advanced malignancies and heralded a new dawn in the cancer armamentarium. However, these remarkable responses are limited to a minority of patients and indications, highlighting the need for more effective and novel approaches. Preclinical and clinical studies with immune checkpoint blockade are exploring the therapeutic potential antibody-based therapy targeting multiple inhibitory receptors. In this chapter, we discuss the current understanding of the structure, ligand specificities, function, and signaling activities of various inhibitory receptors. Additionally, we discuss the current development status of various immune checkpoint inhibitors targeting these negative immune receptors and highlight conceptual gaps in knowledge.

Serum very long-chain fatty acid-containing lipids predict response to immune checkpoint inhibitors in urological cancers.

Checkpoint inhibitors (CPI) have significantly changed the therapeutic landscape of oncology. We adopted a non-invasive metabolomic approach to understand immunotherapy response and failure in 28 urological cancer patients. In total, 134 metabolites were quantified in patient sera before the first, second, and third CPI doses. Modeling the association between metabolites and CPI response and patient characteristics revealed that one predictive metabolite class  (n = 9/10) were very long-chain fatty acid-containing lipids (VLCFA-containing lipids). The best predictive performance was achieved through a multivariate model, including age and a centroid of VLCFA-containing lipids prior to first immunotherapy (sensitivity: 0.850, specificity: 0.825, ROC: 0.935). We hypothesize that the association of VLCFA-containing lipids with CPI response is based on enhanced peroxisome signaling in T cells, which results in a switch to fatty acid catabolism. Beyond use as a novel predictive non-invasive biomarker, we envision that nutritional supplementation with VLCFA-containing lipids might serve as an immuno sensitizer.

Combination Immunotherapy with CAR T Cells and Checkpoint Blockade for the Treatment of Solid Tumors.

Checkpoint blockade (CPB) therapy can elicit durable clinical responses by reactivating an exhausted immune response. However, response rates remain limited, likely secondary to a lack of a tumor-reactive immune infiltrate. Chimeric antigen receptor (CAR) T cells may provide the necessary tumor-targeting immune infiltrate and a highly specific antitumor immune response. This can be further amplified by the addition of CPB agents, which serve to counteract the immune inhibitory environment undermining optimal CAR T cell efficacy. Herein, we review preclinical and clinical combination therapy with CAR T cells and CPB agents, with a focus on solid tumor malignancies.

Alteration in TET1 as potential biomarker for immune checkpoint blockade in multiple cancers.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have achieved impressive success in different cancer types, yet responses vary and predictive biomarkers are urgently needed. Growing evidence points to a link between DNA methylation and anti-tumor immunity, while clinical data on the association of genomic alterations in DNA methylation-related genes and ICI response are lacking. METHODS: Clinical cohorts with annotated response and survival data and matched mutational data from published studies were collected and consolidated. The predictive function of specific mutated genes was first tested in the discovery cohort and later validated in the validation cohort. The association between specific mutated genes and tumor immunogenicity and anti-tumor immunity was further investigated in the Cancer Genome Altas (TCGA) dataset. RESULTS: Among twenty-one key genes involving in the regulation of DNA methylation, TET1-mutant (TET1-MUT) was enriched in patients responding to ICI treatment in the discovery cohort (p=0.003). TET1 was recurrently mutated across multiple cancers and more frequently seen in skin, lung, gastrointestinal, and urogenital cancers. In the discovery cohort (n = 519), significant differences were observed between TET1-MUT and TET1-wildtype (TET1-WT) patients regarding objective response rate (ORR, 60.9% versus 22.8%, P < 0.001), durable clinical benefit (DCB, 71.4% versus 31.6%, P < 0.001), and progression-free survival (PFS, hazard ratio = 0.46 [95% confidence interval, 0.25 to 0.82], P = 0.008). In the validation cohort (n = 1395), significant overall survival (OS) benefit was detected in the TET1-MUT patients compared to TET1-WT patients (hazard ratio = 0.47 [95% confidence interval, 0.25 to 0.88], P = 0.019), which was, importantly, independent of tumor mutational burden and high microsatellite instability; as well as not attributed to the prognostic impact of TET1-MUT (P > 0.05 in both two non-ICI-treated cohorts). In TCGA dataset, TET1-MUT was strongly associated with higher tumor mutational burden and neoantigen load, and inflamed pattern of tumor-infiltrating T lymphocytes, immune signatures and immune-related gene expressions. CONCLUSIONS: TET1-MUT was strongly associated with higher ORR, better DCB, longer PFS, and improved OS in patients receiving ICI treatment, suggesting that TET1-MUT is a novel predictive biomarker for immune checkpoint blockade across multiple cancer types.

Targeted therapies in metastatic gastric cancer: Current knowledge and future perspectives.

Gastric cancer (GC) represents a leading cause of cancer related morbidity and mortality worldwide accounting for more than 1 million of newly diagnosed cases and thousands of deaths every year. In the last decade, the development of targeted therapies and the optimization of already available chemotherapeutic drugs has expanded the available treatment options for advanced GC and granted better survival expectations to the patients. At the same time, global efforts have been undertaken to investigate in detail the genomic and epigenomic heterogeneity of this disease, resulting in the identification of new specific and sensitive predictive and prognostic biomarkers and in innovative molecular classifications based on gene expression profiling. Nonetheless, several randomized studies aimed at exploring new innovative agents, such as immune checkpoint inhibitors, failed to demonstrate clinically meaningful survival advantages. Therefore, it is essential to further improve the molecular characterization of GC subgroups in order to provide researchers and medical oncologists with new tools for patients' selection and stratification in future clinical development programs and subsequent trials. The aim of the present manuscript is to provide a global overview of the recent molecular classifications from The Cancer Genome Atlas and the Asian Cancer Research Group and to present key promising developments in the field of immunotherapy and targeted therapies in metastatic GC.

Inhibitory receptors and ligands beyond PD-1, PD-L1 and CTLA-4: breakthroughs or backups.

Although immunotherapeutics targeting the inhibitory receptors (IRs) CTLA-4, PD-1 or PD-L1 have made substantial clinical progress in cancer, a considerable proportion of patients remain unresponsive to treatment. Targeting novel IR-ligand pathways in combination with current immunotherapies may improve clinical outcomes. New clinical immunotherapeutics target T cell-expressed IRs (LAG-3, TIM-3 and TIGIT) as well as inhibitory ligands in the B7 family (B7-H3, B7-H4 and B7-H5), although many of these targets have complex biologies and unclear mechanisms of action. With only modest clinical success in targeting these IRs, current immunotherapeutic design may not be optimal. This Review covers the biology of targeting novel IR-ligand pathways and the current clinical status of their immunotherapeutics, either as monotherapy or in combination with antibody to PD-1 or to its ligand PD-L1. Further understanding of the basic biology of these targets is imperative to the development of effective cancer immunotherapies.

Low-grade glioma harbors few CD8 T cells, which is accompanied by decreased expression of chemo-attractants, not immunogenic antigens.

In multiple tumor types, prediction of response to immune therapies relates to the presence, distribution and activation state of tumor infiltrating lymphocytes (TILs). Although such therapies are, to date, unsuccessful in gliomas, little is known on the immune contexture of TILs in these tumors. We assessed whether low and high-grade glioma (LGG and HGG, grade II and IV respectively) differ with respect to number, location and tumor reactivity of TILs; as well as expression of molecules involved in the trafficking and activation of T cells. Intra-tumoral CD8 T cells were quantified by flow cytometry (LGG: n = 12; HGG: n = 8) and immunofluorescence (LGG: n = 28; HGG: n = 28). Neoantigen load and expression of Cancer Germline Antigens (CGAs) were assessed using whole exome sequencing and RNA-seq. TIL-derived DNA was sequenced and the variable domain of the TCRß chain was classified according to IMGT nomenclature. QPCR was used to determine expression of T cell-related genes. CD8 T cell numbers were significantly lower in LGG and, in contrast to HGG, mainly remained in close vicinity to blood vessels. This was accompanied by lower expression of chemo-attractants CXCL9, CXCL10 and adhesion molecule ICAM1. We did not observe a difference in the number of expressed neoantigens or CGAs, nor in diversity of TCR-Vß gene usage. In summary, LGG have lower numbers of intra-tumoral CD8 T cells compared to HGG, potentially linked to decreased T cell trafficking. We have found no evidence for distinct tumor reactivity of T cells in either tumor type. The near absence of TILs in LGG suggest that, at present, checkpoint inhibitors are unlikely to have clinical efficacy in this tumor type.

Circulating Tumor Cell-Neutrophil Tango along the Metastatic Process.

The crosstalk between cancer cells and the immune system is crucial for disease progression and its therapeutic targeting is providing exciting results, in particular with newly developed immune checkpoint inhibitors. Current approaches primarily focus on cellular interactions occurring between tumor cells and T lymphocytes; however, recent data highlight a crucial role of neutrophils in support of tumor progression and suggest yet unexplored treatment opportunities. In this review, we summarize the current understanding of those interactions that occur between neutrophils and cancer cells, focusing on both protumor and antitumor activities of neutrophils at different stages of cancer progression. These include infiltration of neutrophils into the primary tumor, their interactions with circulating tumor cells (CTC) within the bloodstream, and their involvement in the establishment of a metastatic niche. Additionally, we discuss how further investigation of CTCs and their interacting immune cell partners may point towards novel immune checkpoint inhibition strategies and provide new insights on the efficacy of already existing immunotherapies.

Immune Checkpoint Inhibitors as Switch or Continuation Maintenance Therapy in Solid Tumors: Rationale and Current State.

First-line chemotherapy for many solid tumors is limited by toxicity. There is a growing interest in maintenance therapy as a strategy for prolonging the benefits of first-line therapy while minimizing toxicity. Maintenance therapy can comprise either continuation of an agent given as part of the first-line regimen (continuation maintenance) or treatment with a new agent (switch maintenance). Maintenance therapy is already established in several solid tumors, including lung, breast, gastric, colorectal, and ovarian cancer. Immune checkpoint inhibitor treatment has been shown to prolong duration of response and overall survival, but efficacy is generally restricted to a limited proportion of patients with selected tumors. Thus, efforts are ongoing to determine whether the clinical benefits of immune checkpoint inhibitors can be extended using novel treatment schedules and settings, including maintenance therapy. Early- and late-phase clinical trials have investigated the efficacy and safety of immune checkpoint inhibitors as switch and continuation maintenance in different tumors, and a range of phase III trials are ongoing. Interpretation of results requires consideration of trial designs, eligibility criteria, and primary endpoints, in addition to biomarker exploration, and assessment of quality of life and cost effectiveness. Findings from ongoing trials will help further define the role of immune checkpoint inhibitors as maintenance therapy across a spectrum of solid tumors.

Development of adaptive immune effector therapies in solid tumors.

State-of-the-art treatment strategies have drastically ameliorated the outcome of patients affected by cancer. However, resistant and recurrent solid tumors are generally nonresponsive to conventional therapies. A central factor in the sequence of events that lead to cancer is an alteration in antitumor immune surveillance, which results in failure to recognize and eliminate the transformed tumor cell. A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of cancer provides the basis for improved therapies. Targeted strategies, such as T-cell therapy, not only generally spare normal tissues, but also use alternative antineoplastic mechanisms that synergize with other therapeutics. Despite encouraging success in hematologic malignancies, adaptive cellular therapies for solid tumors face unique challenges because of the immunosuppressive tumor microenvironment, and the hurdle of T-cell trafficking within scarcely accessible tumor sites. This review provides a brief overview of current cellular therapeutic strategies for solid tumors, research carried out to increase efficacy and safety, and results from ongoing clinical trials.

Application of immune repertoire sequencing in cancer immunotherapy.

With the prominent breakthrough in the field of tumor immunology, diverse cancer immunotherapies have attracted great attention in the last decade. The immune checkpoint inhibitors, adoptive cell therapies, and therapeutic cancer vaccines have already achieved impressive clinical success. However, the fact that only a small subset of patients with specific tumor types can benefit from these treatments limits the application of cancer immunotherapy. To seek out the molecular mechanisms behind this challenge and to select cancer precision medicine for different individuals, researchers apply the immune repertoire sequencing (IRS) to evaluate genetic responses of each patient to current immunotherapies. This review summarizes the technical advances and recent applications of IRS in cancer immunotherapy, indicates the limitations of this technique, and predicts future perspectives both in basic studies and clinical trials.

The prognostic role of obesity is independent of sex in cancer patients treated with immune checkpoint inhibitors: A pooled analysis of 4090 cancer patients.

OBJECTIVE: Recent studies suggest obesity is associated with improved survival of cancer patients treated with immune checkpoint inhibitors (ICIs). We performed this meta-analysis to evaluate the impact of obesity on survival of these patients with regard to the cutoff value of body mass index (BMI) as well as sex. METHODS: Electronic databases including Pubmed, Emabse, and the Cochrane library were systematically searched until April 2019, without language limitation. Clinical studies evaluating the association between BMI and survival of cancer patients treated with ICIs were included. The main endpoints were overall survival (OS) and progression-free survival (PFS). Data from individual studies were extracted by two researchers, independently. RevMan 5.3 and Stata 11 software were used to perform the analysis. RESULTS: 16 retrospective studies met the inclusion criteria, with a total of 4090 patients. The OS (HR = 0.72, 95% CI: 0.51-1.02; P = 0.06) and PFS (HR = 0.67, 95% CI: 0.48-0.95; P = 0.02) of the high BMI group were improved compared with the low BMI group. Dose-response analysis showed that the risk of death decreased by 3.6% when the BMI increased every 1 kg/m2. Subgroup analysis revealed that BMI > 30 was a reliable value for determining significantly better OS (HR = 0.64; 95%CI: 0.43-0.96; P = 0.03). The prognostic effect of BMI on OS was significant regardless of gender (For male, HR = 0.73, 95% CI: 0.61-0.86; P < 0.01. For female, HR = 0.63, 95% CI: 0.43-0.92; P = 0.02). CONCLUSIONS: Obesity is associated with better outcomes in cancer patients treated with ICIs, and this clinical benefit may be independent of sex.

Non-small-cell lung cancer: what are the benefits and challenges of treating it with immune checkpoint inhibitors?

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape of advanced non-small-cell lung cancer (NSCLC). It has improved the overall survival in the first- and second-line setting with manageable adverse events. Multiple challenges still impede the success of ICI in the whole population of NSCLC namely the lack of reliable predictive biomarkers, the scarcity of data regarding the optimal treatment duration with ICI and possibility of rechallenge with ICI as well as the efficacy of ICI in special subgroups of patients such as those with oncogenic addicted tumors or patients with brain metastases. In this framework, we review the benefits and challenges of ICI in NSCLC, in monotherapy and in combinations, in the advanced setting.

A large scale meta analysis identifies common adverse events with checkpoint inhibitors vs chemotherapy in melanoma patients.

BACKGROUND: A meta-analysis was performed to assess the risk of common adverse events in melanoma patients treated with checkpoint inhibitors. METHODS: Eligible studies were downloaded from PubMed, Embase, and Cochrane databases based on an established strategy. Review manager version 5.3 was used to analyze data. RESULTS: After exclusion of ineligible studies, six studies were finally included in the meta-analysis, which comprised of 2136 patients in intervention group and 1773 patients in control group. There was a difference in low grade risk of pruritus (OR 5.63, 95% CI 2.92-10.85, P < 0.00001), diarrhea/colitis (OR 1.51, 95% CI 1.09-2.09, P = 0.01), but not fatigue (low grade, OR 0.96, 95% CI 0.72-1.29, P = 0.80; high grade, OR 0.72, 95% CI 0.23-2.24, P = 0.57) and some high grade risk between the intervention group and control group. Subgroups analysis revealed that low grade risk of pruritus (OR 8.17, 95% CI 4.29-15.55, P < 0.00001) and high grade risk of pruritus (OR 7.08, 95% CI 1.25-40.09, P = 0.03) were significantly different between patients treated with chemotherapy and those treated with checkpoint inhibitors. But fatigue and diarrhea/colitis were not different between the two groups. CONCLUSION: Checkpoint inhibitors are associated with a higher risk in some side effects than chemotherapy in melanoma patients. Therefore, strategies that reduce the risk of adverse events in patients taking checkpoint inhibitors should be developed.

Clinical implications of mismatch repair deficiency in prostate cancer.

Immune checkpoint blockade holds great promise in the treatment of solid tumors but has not yet been approved for use in advanced prostate cancer. This is largely due to the relatively modest response in clinical trials in unselected patients and the lack of available biomarkers to predict clinical benefit. Germline and somatic mismatch repair (MMR) gene deficiencies are more prevalent than previously thought, especially in the metastatic setting, in patients with high-grade Gleason scores and in patients with variant histologies. An early signal suggests that patients with deficiency in MMR may respond well to immunotherapy. Both germline and somatic genetic testing are recommended, yet questions remain on the best modality for testing given lack of standardization and false-negative results in patients with complex genomic structural rearrangements. Expanded panels, such as next generation sequencing may increase the sensitivity without compromising specificity. Future studies are still needed to explore the relationships of hypermutation, tumor mutational burden, tumor-infiltrating lymphocytes and microsatellite instability-H status as predictors of response to immunotherapy. The drivers of variable response is largely unknown, and a more mature understanding of the mechanisms of resistance in deficiencies in MMR tumors may help to more precisely inform use of immunotherapy in prostate cancer.

Toxicity patterns associated with chemotherapy/immune checkpoint inhibitor combinations: a meta-analysis.

Aim: This study aims to clarify toxicity patterns associated with chemotherapy/immune checkpoint inhibitor combinations. Methods: Eligible studies included randomized studies evaluating chemotherapy with or without an immune checkpoint inhibitor (including pembrolizumab, nivolumab, atezolizumab, durvalumab or avelumab). The primary summary statistic was the relative risk (RR). Results: A total of 11 studies were finally included into this meta-analysis. RRs of high-grade anemia, thrombocytopenia and neutropenia were 0.98 (95% CI: 0.83-1.16; p = 0.84), 1.10 (95% CI: 0.83-1.47; p = 0.51) and 0.96 (0.78-1.17; p = 0.66), respectively. RR of high-grade nausea, vomiting and diarrhea was 1.19 (95% CI: 0.78-1.82; p = 0.42), 1.09 (95% CI: 0.69-1.72; p = 0.71) and 2.61 (1.42-4.79; p = 0.002), respectively. Conclusion: Addition of immune checkpoint inhibitors to chemotherapy backbone does not increase the risk of high-grade hematological or gastrointestinal toxicities (except for high-grade diarrhea).