Analysis of the cellular mechanism of antitumor responses and autoimmunity in patients treated with CTLA-4 blockade

Regulatory T Cells Nanoextinguisher to Manipulate Multiple Immune Evasion for Immunotherapy

Regulatory T cells (Treg) play key roles in inhibiting effective antitumor immunity. However, therapeutic Treg depletion fails to consistently enhance immune responses due to the emergence of a wave of peripherally converted Treg cells postdepletion, along with undesired off-target side effects. Here, we report a nanoextinguisher decorated with functional peptides via tumor microenvironment responsive linkers to selectively block Treg function and maintain Treg levels rather than deplete them. The nanoextinguisher specifically neutralizes TGF-β to inhibit the recruitment of Treg cells and the conversion of naive T cells into Treg cells, thus promoting antitumor immunity. Moreover, the nanoextinguisher can alleviate tumor resistance to immunogenic photodynamic therapy, vaccination therapy, and checkpoint inhibition. The nanoextinguisher showed 30-fold potentiation in antitumor effect compared to standalone photodynamic therapy or vaccination therapy. Overall, utilizing a nanoextinguisher to inhibit Treg function without triggering reconversion represents a generalizable method to reverse immune evasion, yielding antitumor efficacy.

Harnessing the capacity of phytochemicals to enhance immune checkpoint inhibitor therapy of cancers: A focus on brain malignancies

Brain cancers, particularly glioblastoma multiforme (GBM), are challenging health issues with frequent unmet aspects. Today, discovering safe and effective therapeutic modalities for brain tumors is among the top research interests. Immunotherapy is an emerging area of investigation in cancer treatment. Since immune checkpoints play fundamental roles in repressing anti-cancer immunity, diverse immune checkpoint inhibitors (ICIs) have been developed, and some monoclonal antibodies have been approved clinically for particular cancers; nevertheless, there are significant concerns regarding their efficacy and safety in brain tumors. Among the various tools to modify the immune checkpoints, phytochemicals show good effectiveness and excellent safety, making them suitable candidates for developing better ICIs. Phytochemicals regulate multiple immunological checkpoint-related signaling pathways in cancer biology; however, their efficacy for clinical cancer immunotherapy remains to be established. Here, we discussed the involvement of immune checkpoints in cancer pathology and summarized recent advancements in applying phytochemicals in modulating immune checkpoints in brain tumors to highlight the state-of-the-art and give constructive prospects for future research.

Advancements in Immunotherapeutic Treatments for Hepatocellular Carcinoma: Potential of Combination Therapies

Hepatocellular carcinoma (HCC) is the sixth most prevalent cancer and a significant global health burden, with increasing incidence rates and limited treatment options. Immunotherapy has become a promising approach due to its ability to affect the immune microenvironment and promote antitumor responses. The immune microenvironment performs an essential role in both the progression and the development of HCC, with different characteristics based on specific immune cells and etiological factors. Immune checkpoint inhibitors, including programmed death-1/programmed death-ligand 1 inhibitors (pembrolizumab, nivolumab, and durvalumab) and cytotoxic T lymphocyte antigen-4 inhibitors (tremelimumab and ipilimumab), have the potential to treat advanced HCC and overcome adverse effects, such as liver failure and chemoresistance. Phase II and phase III clinical trials highlight the efficacy of pembrolizumab and nivolumab, respectively, in advanced HCC patients, as demonstrated by their positive effects on overall survival and progression-free survival. Tremelimumab has exhibited modest response rates, though it does possess antiviral activity. Thus, it is still being investigated in ongoing clinical trials. Combination therapies with multiple drugs have demonstrated potential benefits in terms of survival and tumor response rates, improving patient outcomes compared to monotherapy, especially for advanced-stage HCC. This review addresses the clinical trials of immunotherapies for early-, intermediate-, and advanced-stage HCC. Additionally, it highlights how combination therapy can significantly enhance overall survival, progression-free survival, and objective response rate in advanced-stage HCC, where treatment options are limited.

Establishment and validation of a novel CD8+ T cell-associated prognostic signature for predicting clinical outcomes and immunotherapy response in hepatocellular carcinoma via integrating single-cell RNA-seq and bulk RNA-seq

CD8+ T lymphocytes are critical in the immune response against neoplasms, yet the prognostic relevance of CD8+ T cell-associated genes in hepatocellular carcinoma (HCC) is not fully understood. We sourced single-cell RNA-sequencing (scRNA-seq) and bulk RNA-seq data for HCC from the GSE98638 dataset and The Cancer Genome Atlas (TCGA) repository. We utilized Weighted Gene Correlation Network Analysis (WGCNA) to identify CD8+ T cell-related genes. A clinical prognostic model for risk stratification was then constructed via Cox-Lasso regression analysis. The Immunophenotypic Score (IPS) was utilized to evaluate the potential of immunotherapeutic interventions in the categorized cohorts. Validation of the expression of CD8+ T cell-associated risk genes was performed using quantitative reverse transcription PCR (qRT-PCR). Integrating scRNA-seq with RNA-seq data, we identified five CD8+ T cell-related signature genes: IKBKE, ATP1B3, MSC, ADA, and BATF. Notably, HCC patients in the high-risk group had markedly decreased overall survival. Elevated infiltration levels of CD8+ T cells, B cells, and macrophages were observed in the high-risk group. Moreover, there was a positive correlation between the risk score and immune checkpoints (ICPs), including PDCD1, CD274, and CTLA4. Patients within the high-risk group subject to PD1 and CTLA4 blockade exhibited higher IPS levels. Additionally, the expression of the five risk genes was upregulated in HCC cell lines and tissues compared to normal cells and tissues. Our findings establish a prognostic signature based on CD8+ T cells, offering a potent predictive model for clinical outcomes and responsiveness to immunotherapy in HCC patients.

Immunotherapy for transplantation of hepatocellular carcinoma: the next frontier in adjunctive therapy

PURPOSE OF REVIEW

The increasing success of liver transplantation in hepatocellular carcinoma (HCC) drives an ever-evolving search for innovative strategies to broaden eligible patients' pools. Recent advances in immuno-oncology have turned the spotlight on immune checkpoint inhibitors (ICIs). This review offers an updated overview of ICIs in liver transplantation for HCC, exploring neoadjuvant and adjuvant approaches and addressing unanswered questions on safety, patients' selection, and response predictors.

RECENT FINDINGS

ICIs have transitioned from being a last-chance therapeutic hope to becoming an integral cornerstone in the treatment of advanced HCC, holding great promise as a compelling option not only to downstage patients for transplantation but also as an alternative strategy in addressing posttransplantation disease recurrence. Despite ongoing refinements in immunotherapeutic agents, the complex molecular pathways involved emphasize the need for a comprehensive approach to integrate immunotherapy in liver transplantation.

SUMMARY

Initial concerns about graft rejection, with ICIs as a bridging therapy to liver transplantation, were successfully addressed using adequate immunosuppressants strategies and minimized with a sufficient washout period. Post-liver transplantation disease recurrence remains challenging, requiring a balance between effective therapy and preserving graft function. Emphasis should be placed on clinical trials validating the risk-benefit ratio of ICIs for liver transplantation, guiding appropriate patients' selection, and establishing clear management pathways.

Opportunistic Infections and Immune-Related Adverse Events Associated with Administering Immune Checkpoint Inhibitors: A Narrative Review

Manipulating the immune system by blocking the immune checkpoint receptors is the basis of immunotherapy, a relevant tool in current clinical oncology. The strategy of blocking the immune checkpoints (Immune Checkpoint Inhibitors, ICI) consists of using monoclonal antibodies to inhibit the interaction between ligand and inhibitory receptors from triggering a complete activation of helper and cytotoxic T cells to fight against tumour cells. Immunotherapy has benefited patients with diverse cancers such as stomach, lung, melanoma, and head and neck squamous cell carcinoma, among others. Unfortunately, a growing number of reports have indicated that the ICI treatment also can show a dark side under specific conditions; some of the adverse effects induced by ICI are immunosuppression, opportunistic infections, and organ-specific alterations. This review discusses some immunologic aspects related to these unwanted effects.

A year in pharmacology: new drugs approved by the US Food and Drug Administration in 2022

While new drug approvals by the U.S. Food and Drug Administration (FDA) had remained stable or even increased in the first 2 years of the COVID-19 pandemic, the 37 newly approved drugs in 2022 are considerably less than the 53 and 50 new drugs approved in 2020 and 2021, respectively, and less than the rolling 10-year average of 43. As in previous years of this annual review, we assign these new drugs to one of three levels of innovation: first drug against a condition ("first-in-indication"), first drug using a novel molecular mechanism ("first-in-class"), and "next-in-class," i.e., a drug using an already exploited molecular mechanism. We identify two "first-in-indication" (ganaxolon and teplizumab), 20 (54%) "first-in-class," and 17 (46%) "next-in-class" drugs. By treatment area, rare diseases and cancer drugs were once again the most prevalent (partly overlapping) therapeutic areas. Other continuing trends were the use of accelerated regulatory approval pathways and the reliance on biopharmaceuticals (biologics).

Immune checkpoint inhibitors in hepatocellular carcinoma: emerging challenges in clinical practice

Systemic therapy for advanced hepatocellular carcinoma has expanded at an unprecedented pace over the past 5 years. After tyrosine kinase inhibitors dominated the field for more than a decade, immune checkpoint inhibitor (ICI)-based therapies have become the main component in systemic first-line treatment of this cancer. Delivery of immunotherapy in routine clinical practice recognises several challenges. In this Viewpoint, we discuss the major gaps in knowledge around the role of ICI-based therapies in patients with Child-Pugh class B. We discuss the challenges in individuals with rare histological subtypes of primary liver cancer, including combined hepatocellular-cholangiocarcinoma, fibrolamellar hepatocellular carcinoma, and sarcomatoid hepatocellular carcinoma. We also review data on ICI rechallenge in patients previously treated with ICIs, and discuss atypical patterns of progression related to immunotherapy (ie, hyperprogressive disease and pseudoprogression).

Immune Checkpoint Inhibitors in Hepatocellular Carcinoma: Current Strategies and Biomarkers Predicting Response and/or Resistance

In recent years, immune checkpoint inhibitors (ICIs) have revolutionized the treatment of patients with hepatocellular carcinoma (HCC). Following the positive results of the IMbrave150 trial, the combination of atezolizumab (an anti-PD-L1 antibody) and bevacizumab (an anti-VEGF antibody) became the standard of care frontline treatment for patients with advanced stage HCC. Several other trials evaluated immunotherapy in HCC, demonstrating that ICIs-based regimens are currently the most effective treatment strategies and expanding the therapeutic possibilities. Despite the unprecedent rates of objective tumor response, not all patients benefit from treatment with ICIs. Therefore, in order to select the appropriate therapy as well as to correctly allocate medical resources and avoid unnecessary treatment-related toxicities, there is great interest in identifying the predictive biomarkers of response or resistance to immunotherapy-based regimens. Immune classes of HCC, genomic signatures, anti-drug antibodies, and patient-related factors (e.g., etiology of liver disease, gut microbiota diversity) have been associated to the response to ICIs, but none of the proposed biomarkers have been translated into clinical practice so far. Considering the crucial importance of this topic, in this review we aim to summarize the available data on tumor and clinical features associated with the response or resistance of HCC to immunotherapies.

An Immunological Perspective on the Mechanism of Drug Induced Liver Injury: Focused on Drugs for Treatment of Hepatocellular Carcinoma and Liver Transplantation

The liver is frequently exposed to potentially toxic materials, and it is the primary site of clearance of foreign agents, along with many innate and adaptive immune cells. Subsequently, drug induced liver injury (DILI), which is caused by medications, herbs, and dietary supplements, often occurs and has become an important issue in liver diseases. Reactive metabolites or drug-protein complexes induce DILI via the activation of various innate and adaptive immune cells. There has been a revolutionary development of treatment drugs for hepatocellular carcinoma (HCC) and liver transplantation (LT), including immune checkpoint inhibitors (ICIs), that show high efficacy in patients with advanced HCC. Along with the high efficacy of novel drugs, DILI has become a pivotal issue in the use of new drugs, including ICIs. This review demonstrates the immunological mechanism of DILI, including the innate and adaptive immune systems. Moreover, it aims to provide drug treatment targets, describe the mechanisms of DILI, and detail the management of DILI caused by drugs for HCC and LT.

Evolving therapeutic landscape of advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common solid malignancies worldwide. A large proportion of patients with HCC are diagnosed at advanced stages and are only amenable to systemic therapies. We have witnessed the evolution of systemic therapies from single-agent targeted therapy (sorafenib and lenvatinib) to the combination of a checkpoint inhibitor plus targeted therapy (atezolizumab plus bevacizumab therapy). Despite remarkable advances, only a small subset of patients can obtain durable clinical benefit, and therefore substantial therapeutic challenges remain. In the past few years, emerging systemic therapies, including new molecular-targeted monotherapies (for example, donafenib), new immuno-oncology monotherapies (for example, durvalumab) and new combination therapies (for example, durvalumab plus tremelimumab), have shown encouraging results in clinical trials. In addition, many novel therapeutic approaches with the potential to offer improved treatment effects in patients with advanced HCC, such as sequential combination targeted therapy and next-generation adoptive cell therapy, have also been proposed and developed. In this Review, we summarize the latest clinical advances in the treatment of advanced HCC and discuss future perspectives that might inform the development of more effective therapeutics for advanced HCC.

Recent Update on Immunotherapy and Its Combination With Interventional Therapies for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common and deadly malignancies worldwide. Approximately, 80% of patients are initially diagnosed at intermediate or advanced stages, which means that curative therapies are unable to be performed. In most cases, systemic treatment is ineffective, especially when conventional cytotoxic agents are used. Sorafenib has been the only systemic agent proven to be effective in treating advanced HCC for over a decade. The rapid development of immunotherapy has remarkably revolutionized the management of advanced HCC. Besides, the combination of immunotherapy with molecular targeted agents or locoregional treatments is emerging as an effective tool for enhancing immunity. In the review, an overview of immunotherapy and its combination therapies for HCC is presented.

Second-line treatment options for hepatocellular carcinoma: current state and challenges for the future

INTRODUCTION

Since the approval of sorafenib for systemic treatment of advanced hepatocellular carcinoma (HCC), many tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs) have shown efficacy and tolerability as first-line treatments. On the other hand, these first-line therapies are associated with low objective response and drug resistance. Many drugs have been successfully tested for second-line treatment of advanced HCC. While the rapid proliferation of second-line treatments for advanced HCC brings hope to patients, it also complicates clinical decision-making.

AREAS COVERED

This review aims to facilitate decisions by summarizing the latest guidelines for second-line treatment of HCC in various countries or regions. We then review existing second-line treatment options and discuss challenges that should be addressed in the future. A literature search was conducted in April 2022 of PubMed/Medline, Cochrane library, and abstracts of international cancer meetings.

EXPERT OPINION

There is no standard second-line treatment, especially for the case of sequential treatment after atezolizumab plus bevacizumab (atezo+bev) and further studies focused on sequential treatment are warranted in this setting. The design of clinical trials, different etiologies, and complications or quality of life (QoL) are interesting issues in the second-line setting.

Local delivery of low-dose anti–CTLA-4 to the melanoma lymphatic basin leads to systemic T reg reduction and effector T cell activation

Preclinical studies show that locoregional CTLA-4 blockade is equally effective in inducing tumor eradication as systemic delivery, without the added risk of immune-related side effects. This efficacy is related to access of the CTLA-4 blocking antibodies to tumor-draining lymph nodes (TDLNs). Local delivery of anti–CTLA-4 after surgical removal of primary melanoma, before sentinel lymph node biopsy (SLNB), provides a unique setting to clinically assess the role of TDLN in the biological efficacy of locoregional CTLA-4 blockade. Here, we have evaluated the safety, tolerability, and immunomodulatory effects in the SLN and peripheral blood of a single dose of tremelimumab [a fully human immunoglobulin gamma-2 (IgG2) mAb directed against CTLA-4] in a dose range of 2 to 20 mg, injected intradermally at the tumor excision site 1 week before SLNB in 13 patients with early-stage melanoma (phase 1 trial; NCT04274816). Intradermal delivery was safe and well tolerated and induced activation of migratory dendritic cell (DC) subsets in the SLN. It also induced profound and durable decreases in regulatory T cell (T reg ) frequencies and activation of effector T cells in both SLN and peripheral blood. Moreover, systemic T cell responses against NY-ESO-1 or MART-1 were primed or boosted ( N = 7), in association with T cell activation and central memory T cell differentiation. These findings indicate that local administration of anti–CTLA-4 may offer a safe and promising adjuvant treatment strategy for patients with early-stage melanoma. Moreover, our data demonstrate a central role for TDLN in the biological efficacy of CTLA-4 blockade and support TDLN-targeted delivery methods.

Emerging Therapies for Hepatocellular Carcinoma (HCC)

Hepatocellular carcinoma (HCC) arises from hepatocytes and accounts for 90% of primary liver cancer. According to Global Cancer Incidence, Mortality and Prevalence (GLOBOCAN) 2020, globally HCC is the sixth most common cancer and the third most common cause of cancer-related deaths. Reasons for HCC prognosis remaining dismal are that HCC is asymptomatic in its early stages, leading to late diagnosis, and it is markedly resistant to conventional chemo- and radiotherapy. Liver transplantation is the treatment of choice in early stages, while surgical resection, radiofrequency ablation (RFA) and trans arterial chemoembolization (TACE) are Food and Drug Administration (FDA)-approved treatments for advanced HCC. Additional first line therapy for advanced HCC includes broad-spectrum tyrosine kinase inhibitors (TKIs), such as sorafenib and lenvatinib, as well as a combination of immunotherapy and anti-angiogenesis therapy, namely atezolizumab and bevacizumab. However, these strategies provide nominal extension in the survival curve, cause broad spectrum toxic side effects, and patients eventually develop therapy resistance. Some common mutations in HCC, such as in telomerase reverse transcriptase (TERT), catenin beta 1 (CTNNB1) and tumor protein p53 (TP53) genes, are still considered to be undruggable. In this context, identification of appropriate gene targets and specific gene delivery approaches create the potential of gene- and immune-based therapies for the safe and effective treatment of HCC. This review elaborates on the current status of HCC treatment by focusing on potential gene targets and advanced techniques, such as oncolytic viral vectors, nanoparticles, chimeric antigen receptor (CAR)-T cells, immunotherapy, and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9), and describes future prospects in HCC treatment.

Novel immunotherapy combinations in clinical trials for hepatocellular carcinoma: will they shape the future treatment landscape?

INTRODUCTION

Underlying liver disease and the intrinsic chemoresistance have historically hampered the development of efficacious treatments in HCC. However, in the last few years, immunotherapy-based combinations have emerged as efficacious therapeutic strategy in this setting. This paper critically summarizes the recent therapeutic progress in the systemic treatment of HCC.

AREA COVERED

This paper examines the preclinical rationale of the following combinations in HCC: dual checkpoint inhibitors, immune checkpoint inhibitors plus anti-angiogenic agents, and immune checkpoint inhibitors plus tyrosine kinase inhibitors. Results of recent clinical studies are presented, along with a brief overview of ongoing and future trials.

EXPERT OPINION

The approval of atezolizumab plus bevacizumab and the positive results of the HIMALAYA trial have broadened the therapeutic scenario for advanced HCC, opening, at the same time, new challenges. First of all, predictive biomarkers to allocate patients to the best treatment are eagerly required; second, specific studies are urgently needed to define the use of new combinations in patients usually excluded from clinical trials, e.g. those with deranged liver function and HIV or transplant recipients. Finally, with new combinations being translated into earlier stages, profound changes are soon expected in the adjuvant and neoadjuvant setting.

The Current State of Treatment and Future Directions in Cutaneous Malignant Melanoma

Malignant melanoma is the leading cause of death among cutaneous malignancies. While its incidence is increasing, the most recent cancer statistics show a small but clear decrease in mortality rate. This trend reflects the introduction of novel and more effective therapeutic regimens, including the two cornerstones of melanoma therapy: immunotherapies and targeted therapies. Immunotherapies exploit the highly immunogenic nature of melanoma by modulating and priming the patient's own immune system to attack the tumor. Treatments combining immunotherapies with targeted therapies, which disable the carcinogenic products of mutated cancer cells, have further increased treatment efficacy and durability. Toxicity and resistance, however, remain critical challenges to the field. The present review summarizes past treatments and novel therapeutic interventions and discusses current clinical trials and future directions.

Addressing the Elephant in the Immunotherapy Room: Effector T-Cell Priming versus Depletion of Regulatory T-Cells by Anti-CTLA-4 Therapy

Cytotoxic T-lymphocyte Associated Protein 4 (CTLA-4) is an immune checkpoint molecule highly expressed on regulatory T-cells (Tregs) that can inhibit the activation of effector T-cells. Anti-CTLA-4 therapy can confer long-lasting clinical benefits in cancer patients as a single agent or in combination with other immunotherapy agents. However, patient response rates to anti-CTLA-4 are relatively low, and a high percentage of patients experience severe immune-related adverse events. Clinical use of anti-CTLA-4 has regained interest in recent years; however, the mechanism(s) of anti-CTLA-4 is not well understood. Although activating T-cells is regarded as the primary anti-tumor mechanism of anti-CTLA-4 therapies, mounting evidence in the literature suggests targeting intra-tumoral Tregs as the primary mechanism of action of these agents. Tregs in the tumor microenvironment can suppress the host anti-tumor immune responses through several cell contact-dependent and -independent mechanisms. Anti-CTLA-4 therapy can enhance the priming of T-cells by blockading CD80/86-CTLA-4 interactions or depleting Tregs through antibody-dependent cellular cytotoxicity and phagocytosis. This review will discuss proposed fundamental mechanisms of anti-CTLA-4 therapy, novel uses of anti-CTLA-4 in cancer treatment and approaches to improve the therapeutic efficacy of anti-CTLA-4.

Immunotherapies for hepatocellular carcinoma

Liver cancer, more specifically hepatocellular carcinoma (HCC), is the second leading cause of cancer-related death and its incidence is increasing globally. Around 50% of patients with HCC receive systemic therapies, traditionally sorafenib or lenvatinib in the first line and regorafenib, cabozantinib or ramucirumab in the second line. In the past 5 years, immune-checkpoint inhibitors have revolutionized the management of HCC. The combination of atezolizumab and bevacizumab has been shown to improve overall survival relative to sorafenib, resulting in FDA approval of this regimen. More recently, durvalumab plus tremelimumab yielded superior overall survival versus sorafenib and atezolizumab plus cabozantinib yielded superior progression-free survival. In addition, pembrolizumab monotherapy and the combination of nivolumab plus ipilimumab have received FDA Accelerated Approval in the second-line setting based on early efficacy data. Despite these major advances, the molecular underpinnings governing immune responses and evasion remain unclear. The immune microenvironment has crucial roles in the development and progression of HCC and distinct aetiology-dependent immune features have been defined. Inflamed and non-inflamed classes of HCC and genomic signatures have been associated with response to immune-checkpoint inhibitors, yet no validated biomarker is available to guide clinical decision-making. This Review provides information on the immune microenvironments underlying the response or resistance of HCC to immunotherapies. In addition, current evidence from phase III trials on the efficacy, immune-related adverse events and aetiology-dependent mechanisms of response are described. Finally, we discuss emerging trials assessing immunotherapies across all stages of HCC that might change the management of this disease in the near future.

The foundations of immune checkpoint blockade and the ipilimumab approval decennial

Cancer immunity, and the potential for cancer immunotherapy, have been topics of scientific discussion and experimentation for over a hundred years. Several successful cancer immunotherapies - such as IL-2 and interferon-α (IFNα) - have appeared over the past 30 years. However, it is only in the past decade that immunotherapy has made a broad impact on patient survival in multiple high-incidence cancer indications. The emergence of immunotherapy as a new pillar of cancer treatment (adding to surgery, radiation, chemotherapy and targeted therapies) is due to the success of immune checkpoint blockade (ICB) drugs, the first of which - ipilimumab - was approved in 2011. ICB drugs block receptors and ligands involved in pathways that attenuate T cell activation - such as cytotoxic T lymphocyte antigen 4 (CTLA4), programmed cell death 1 (PD1) and its ligand, PDL1 - and prevent, or reverse, acquired peripheral tolerance to tumour antigens. In this Review we mark the tenth anniversary of the approval of ipilimumab and discuss the foundational scientific history of ICB, together with the history of the discovery, development and elucidation of the mechanism of action of the first generation of drugs targeting the CTLA4 and PD1 pathways.

Exosome CTLA-4 Regulates PTEN/CD44 Signal Pathway in Spleen Deficiency Internal Environment to Promote Invasion and Metastasis of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common primary cancers, and its pathogenesis is complicated and difficult to screen. Currently, there is no effective treatment. In traditional Chinese medicine, a large proportion of patients with HCC have been diagnosed with spleen deficiency (SD) syndrome and treated with tonifying traditional Chinese medicine, which has significant clinical efficacy. However, the role and molecular mechanism of SD in HCC remain unclear. In this study, 40 mice were randomly divided into four groups: control, SD, HCC, and SD-HCC groups. The liver cancer model of SD was established by reserpine induction and orthotopic transplantation. The effects of SD on the proliferation, apoptosis, invasion, and metastasis of HCC cells were studied by cell proliferation, cell apoptosis, cell scratch, and transwell assay. We found that compared with the HCC group, the protein expressions of cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), phosphatase and tensin homolog (PTEN), and AKT (also known as protein kinase B or PKB) in the exosomes of the SD-HCC group were upregulated. In addition, the metastases and self-renewal of exosomes in the SD-HCC group were more aggressive than those in the HCC group, which could be partially reversed with the addition of CTLA-4 inhibitors. Further studies showed that in the internal environment of SD, CTLA-4 promoted tumor invasion and metastasis by regulating the PTEN/CD44 pathway. In conclusion, our findings suggest that during SD in the internal environment, exosome CTLA-4 regulates the PTEN/CD44 signal pathway to promote the proliferation, self-renewal, and metastasis of liver cancer.

Checkpoint Inhibitor Colitis Shows Drug-Specific Differences in Immune Cell Reaction That Overlap With Inflammatory Bowel Disease and Predict Response to Colitis Therapy

OBJECTIVES

Checkpoint inhibitor (CPI)-associated colitis can limit therapy and has resemblance to inflammatory bowel disease (IBD). Studies exploring mechanistic similarities between these colitides are limited, yet therapeutic targets for either disorder could emerge from shared pathophysiology.

METHODS

The morphology and inflammatory content of colonic biopsy specimens from anti-CTLA-4 and anti-PD-1/PD-L1 antibody-treated patients with CPI colitis were compared with initial biopsy specimens from patients with IBD. Predictors of the need for infliximab were sought in CPI patients.

RESULTS

Biopsy specimens from CPI patients showed significantly lower chronicity scores and similar activity scores compared with patients with IBD. Anti-CTLA-4 and IBD groups showed equivalent CD8, CD4, PD-1, and PD-L1 expression, while FoxP3 scores were lower and CD68 scores were higher in anti-CTLA-4 compared with IBD biopsy specimens. Anti-PD-1/PD-L1 group had lower scores for CD8, CD4, and PD-1 and equivalent scores for FoxP3, PD-L1, and CD68 compared with IBD. Anti-CTLA-4 biopsy specimens had higher scores for CD8, PD-1, PD-L1, and CD68 than anti-PD-1/PD-L1 biopsy specimens. CD8/FoxP3 ratios and CD68 scores were higher among CPI patients requiring infliximab therapy for colitis compared with those responding to steroids.

CONCLUSIONS

The proinflammatory immune phenotype of anti-CTLA-4-associated colitis has significant overlap with IBD. CD8/FoxP3 ratios may predict therapeutic response in CPI-associated colitis.

Immune Cell Profiling of Peripheral Blood as Signature for Response During Checkpoint Inhibition Across Cancer Types

Despite encouraging results with immune checkpoint inhibition (ICI), a large fraction of cancer patients still does not achieve clinical benefit. Finding predictive markers in the complexity of the tumor microenvironment is a challenging task and often requires invasive procedures. In our study, we looked for putative variables related to treatment benefit among immune cells in peripheral blood across different tumor types treated with ICIs. For that, we included 33 patients with different solid tumors referred to our clinical unit for ICI. Peripheral blood mononuclear cells were isolated at baseline, 6 and 20 weeks after treatment start. Characterization of immune cells was carried out by multi-color flow cytometry. Response to treatment was assessed radiologically by RECIST 1.1. Clinical outcome correlated with a shift towards an effector-like T cell phenotype, PD-1 expression by CD8+T cells, low levels of myeloid-derived suppressor cells and classical monocytes. Dendritic cells seemed also to play a role in terms of survival. From these findings, we hypothesized that patients responding to ICI had already at baseline an immune profile, here called ‘favorable immune periphery’, providing a higher chance of benefitting from ICI. We elaborated an index comprising cell types mentioned above. This signature correlated positively with the likelihood of benefiting from the treatment and ultimately with longer survival. Our study illustrates that patients responding to ICI seem to have a pre-existing immune profile in peripheral blood that favors good outcome. Exploring this signature can help to identify patients likely to achieve benefit from ICI.

Combination Immunotherapy With LIGHT and Interleukin-2 Increases CD8 Central Memory T-Cells In Vivo

BACKGROUND

The generation of long-term durable tumor immunity and prolonged disease-free survival depends on the ability to generate and support CD8+ central memory T-cells. Microsatellite-stable colon cancer is resistant to currently available immunotherapies; thus, development of novel mechanisms to increase both lymphocyte infiltration and central memory formation are needed to improve outcomes in these patients. We have previously demonstrated that both interleukin-2 (IL-2) and LIGHT (TNFSF14) independently enhance antitumor immune responses and hypothesize that combination immunotherapy may increase the CD8+ central memory T-cell response.

METHODS

Murine colorectal cancer tumors were established in syngeneic mice. Tumors were treated with control, soluble, or liposomal IL-2 at established intervals. A subset of animal tumors overexpressed tumor necrosis superfamily factor LIGHT (TNFSF14). Peripheral blood, splenic, and tumor-infiltrating lymphocytes were isolated for phenotypic studies and flow cytometry.

RESULTS

Tumors exposed to a combination of LIGHT and IL-2 experienced a decrease in tumor size compared with IL-2 alone that was not demonstrated in wild-type tumors or between other treatment groups. Combination exposure also increased splenic central memory CD8+ cells compared with IL-2 administration alone, while not increasing tumor-infiltrating lymphocytes. In the periphery, the combination enhanced levels of circulating CD8 T-cells and central memory T-cells, while also increasing circulating T-regulatory cells.

CONCLUSIONS

Combination of IL-2, whether soluble or liposomal, with exposure to LIGHT results in increased CD8+ central memory cells in the spleen and periphery. New combination immunotherapy strategies that support both effector and memory T-cell functions are critical to enhancing durable antitumor responses and warrant further investigation.

Emerging dynamics pathways of response and resistance to PD-1 and CTLA-4 blockade: tackling uncertainty by confronting complexity

Immune checkpoint inhibitors provide considerable therapeutic benefit in a range of solid cancers as well as in a subgroup of hematological malignancies. Response rates are however suboptimal, and despite considerable efforts, predicting response to immune checkpoint inhibitors ahead of their administration in a given patient remains elusive. The study of the dynamics of the immune system and of the tumor under immune checkpoint blockade brought insight into the mechanisms of action of these therapeutic agents. Equally relevant are the mechanisms of adaptive resistance to immune checkpoint inhibitors that have been uncovered through this approach. In this review, we discuss the dynamics of the immune system and of the tumor under immune checkpoint blockade emanating from recent studies on animal models and humans. We will focus on mechanisms of action and of resistance conveying information predictive of therapeutic response.

Anti-CTLA-4 antibody-functionalized dendritic cell-derived exosomes targeting tumor-draining lymph nodes for effective induction of antitumor T-cell responses

The therapeutic efficacy of current cancer vaccines is far from optimal, mainly because of insufficient induction of antigen-specific T cells and because tumor cells can hijack immunosuppressive mechanisms to evade the immune responses. Generating specific, robust, and long-term immune responses against cancer cells and the attenuating of immunosuppressive factors are critical for effective cancer vaccination. Recently, the engineering of exosomes specifically bind to T cells, and then stimulating tumor-specific T-cell immune responses has emerged as a potential alternative strategy for cancer vaccination. In this study, we generated a bifunctional exosome combining the strategy of vaccination and checkpoint blockade. Exosomes prepared from Ovalbumin (OVA)-pulsed, activated dendritic cells were modified with anti-CTLA-4 antibody (EXO-OVA-mAb) to block this inhibitory molecule and to enhance the specificity of the exosomes toward T cells. Our study provides a unique strategy for functionalizing exosome membrane with anti-CTLA-4 antibody via lipid-anchoring method to synergize efficacy of cancer vaccination and immune checkpoint blockade against the tumor. STATEMENT OF SIGNIFICANCE: We designed T-cell-targeting exosomes (EXO-OVA-mAb) decorated with costimulatory molecules, MHCs, antigenic OVA peptide, and anti-CTLA-4 antibody, combining the strategies of vaccines and checkpoint blockade. The exosomes showed enhanced binding to T cells in tumor-draining lymph nodes, effectively induced T-cell activation, and improved the tumor homing of effector T cells, ultimately significantly restraining tumor growth. Thus, EXO-OVA-mAb greatly facilitates T-cell targeting, induces a strong tumor-specific T-cell response, and increased the ratio of effector T cells/regulatory T cells within tumors, resulting in appreciable tumor growth inhibition.

Ab locks for improving the selectivity and safety of antibody drugs

Monoclonal antibodies (mAbs) are a major targeted therapy for malignancies, infectious diseases, autoimmune diseases, transplant rejection and chronic inflammatory diseases due to their antigen specificity and longer half-life than conventional drugs. However, long-term systemic antigen neutralization by mAbs may cause severe adverse events. Improving the selectivity of mAbs to distinguish target antigens at the disease site from normal healthy tissue and reducing severe adverse events caused by the mechanisms-of-action of mAbs is still a pressing need. Development of pro-antibodies (pro-Abs) by installing a protease-cleavable Ab lock is a novel and advanced recombinant Ab-based strategy that efficiently masks the antigen binding ability of mAbs in the normal state and selectively "turns on" the mAb activity when the pro-Ab reaches the proteolytic protease-overexpressed diseased tissue. In this review, we discuss the design and advantages/disadvantages of different Ab lock strategies, focusing particularly on spatial-hindrance-based and affinity peptide-based approaches. We expect that the development of different masking strategies for mAbs will benefit the local reactivity of mAbs at the disease site, increase the therapeutic efficacy and safety of long-term treatment with mAbs in chronic diseases and even permit scientists to develop Ab drugs for formerly undruggable targets and satisfy the unmet medical needs of mAb therapy.

Dawn of Monitoring Regulatory T Cells in (Pre-)clinical Studies: Their Relevance Is Slowly Recognised

Regulatory T cells (Tregs) have a prominent role in the control of immune homeostasis. Pharmacological impact on their activity or balance with effector T cells could contribute to (impaired) clinical responses or adverse events. Monitoring treatment-related effects on T cell subsets may therefore be part of (pre-)clinical studies for medicinal products. However, the extent of immune monitoring performed in studies for marketing authorisation and the degree of correspondence with data available in the public domain is not known. We evaluated the presence of T cell immunomonitoring in 46 registration dossiers of monoclonal antibodies indicated for immune-related disorders and published scientific papers. We found that the depth of Treg analysis in registration dossiers was rather small. Nevertheless, data on treatment-related Treg effects are available in public academia-driven studies (post-registration) and suggest that Tregs may act as a biomarker for clinical responses. However, public data are fragmented and obtained with heterogeneity of experimental approaches from a diversity of species and tissues. To reveal the potential added value of T cell (and particular Treg) evaluation in (pre-)clinical studies, more cell-specific data should be acquired, at least for medicinal products with an immunomodulatory mechanism. Therefore, extensive analysis of T cell subset contribution to clinical responses and the relevance of treatment-induced changes in their levels is needed. Preferably, industry and academia should work together to obtain these data in a standardised manner and to enrich our knowledge about T cell activity in disease pathogenesis and therapies. This will ultimately elucidate the necessity of T cell subset monitoring in the therapeutic benefit-risk assessment.

Harnessing neoantigen specific CD4 T cells for cancer immunotherapy

The goal of precision immunotherapy is to direct a patient's T cell response against the immunogenic mutations expressed on their tumors. Most immunotherapy approaches to-date have focused on MHC class I-restricted peptide epitopes by which cytotoxic CD8+ T lymphocytes (CTL) can directly recognize tumor cells. This strategy largely overlooks the critical role of MHC class II-restricted CD4+ T cells as both positive regulators of CTL and other effector cell types, and as direct effectors of antitumor immunity. In this review, we will discuss the role of neoantigen specific CD4+ T cells in cancer immunotherapy and how existing treatment modalities may be leveraged to engage this important T cell subset.

Triple-Negative Breast Cancer: A Review of Conventional and Advanced Therapeutic Strategies

Triple-negative breast cancer (TNBC) cells are deficient in estrogen, progesterone and ERBB2 receptor expression, presenting a particularly challenging therapeutic target due to their highly invasive nature and relatively low response to therapeutics. There is an absence of specific treatment strategies for this tumor subgroup, and hence TNBC is managed with conventional therapeutics, often leading to systemic relapse. In terms of histology and transcription profile these cancers have similarities to BRCA-1-linked breast cancers, and it is hypothesized that BRCA1 pathway is non-functional in this type of breast cancer. In this review article, we discuss the different receptors expressed by TNBC as well as the diversity of different signaling pathways targeted by TNBC therapeutics, for example, Notch, Hedgehog, Wnt/b-Catenin as well as TGF-beta signaling pathways. Additionally, many epidermal growth factor receptor (EGFR), poly (ADP-ribose) polymerase (PARP) and mammalian target of rapamycin (mTOR) inhibitors effectively inhibit the TNBCs, but they face challenges of either resistance to drugs or relapse. The resistance of TNBC to conventional therapeutic agents has helped in the advancement of advanced TNBC therapeutic approaches including hyperthermia, photodynamic therapy, as well as nanomedicine-based targeted therapeutics of drugs, miRNA, siRNA, and aptamers, which will also be discussed. Artificial intelligence is another tool that is presented to enhance the diagnosis of TNBC.

Deciphering and Reversing Immunosuppressive Cells in the Treatment of Hepatocellular Carcinoma

Use of immune checkpoint inhibitors (ICIs) in hepatocellular carcinoma (HCC) has been partially successful. However, most HCC patients do not respond to immunotherapy. HCC has been shown to induce several immune suppressor mechanisms in patients. These suppressor mechanisms include involvement of myeloid-derived suppressor cells, regulatory T-cells, functionally impaired dendritic cells (DCs), neutrophils, monocytes, and tumor associated macrophages. The accumulation of immunosuppressive cells may lead to an immunosuppressive tumor microenvironment as well as the dense fibrotic stroma which may contribute to immune tolerance. Our laboratory has been investigating different cellular mechanisms of immune suppression in HCC patients. In vitro as well as in vivo studies have demonstrated that abrogation of the suppressor cells enhances or unmasks tumor-specific antitumor immune responses. Two or three effective systemic therapies including ICIs and/or molecular targeted therapies and the addition of innovative combination therapies targeting immune suppressor cells may lead to increased immune recognition with a greater tumor response. We reviewed the literature for the latest research on immune suppressor cells in HCC, and here we provide a comprehensive summary of the recent studies in this field.

The Use of Analgesics during Vaccination with a Live Attenuated Yersinia pestis Vaccine Alters the Resulting Immune Response in Mice

The administration of antipyretic analgesics prior to, in conjunction with, or due to sequelae associated with vaccination is a common yet somewhat controversial practice. In the context of human vaccination, it is unclear if even short-term analgesic regimens can significantly alter the resulting immune response, as literature exists to support several scenarios including substantial immune interference. In this report, we used a live attenuated Yersinia pestis vaccine to examine the impact of analgesic administration on the immune response elicited by a single dose of a live bacterial vaccine in mice. Mice were assessed by evaluating natural and provoked behavior, as well as food and water consumption. The resulting immune responses were assessed by determining antibody titers against multiple antigens and assaying cellular responses in stimulated splenocytes collected from vaccinated animals. We observed no substantial benefit to the mice associated with the analgesic administration. Splenocytes from both C57BL/6 and BALB/c vaccinated mice receiving acetaminophen have a significantly reduced interferon-gamma (IFN-γ) recall response. Additionally, there is a significantly lower immunoglobulin (Ig)G2a/IgG1 ratio in vaccinated BALB/c mice treated with either acetaminophen or meloxicam and a significantly lower IgG2c/IgG1 ratio in vaccinated C57BL/6 mice treated with acetaminophen. Taken together, our data indicate that the use of analgesics, while possibly ethically warranted, may hinder the accurate characterization and evaluation of novel vaccine strategies with little to no appreciable benefits to the vaccinated mice.

Balancing cancer immunotherapy and immune-related adverse events: The emerging role of regulatory T cells

Advances in our understanding οf tumor immunity have prompted a paradigm shift in oncology, with the emergence of immunotherapy, where therapeutic agents are used to target immune cells rather than cancer cells. A real breakthrough in the field of immunotherapy came with the use of immune checkpoint inhibitors (ICI), namely antagonistic antibodies that block key immune regulatory molecules (checkpoint molecules), such as cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), programmed cell death protein (PD-1) and its ligand PD-L1, that under physiologic conditions suppress T cell effector function. However, despite the enormous success, a significant proportion of patients do not respond, while responses are frequently accompanied by life-threatening autoimmune related adverse events (irAEs). A major impediment in the effectiveness of ICI immunotherapy is the tumoral resistance, which is dependent on the immunosuppressive nature of tumor microenvironment (TME). Regulatory T cells (Tregs) are among the most abundant suppressive cells in the TME and their presence has been correlated with tumor progression, invasiveness as well as metastasis. Tregs are characterized by the expression of the transcription factor Foxp3 and various mechanisms ranging from cell-to-cell contact to secretion of inhibitory molecules have been implicated in their function. Notably, Tregs amply express most of the checkpoint molecules such as CTLA4, PD1 and LAG3 and therefore represent a direct target of ICI immunotherapy. Taking into consideration the critical role of Tregs in maintenance of immune homeostasis and avoidance of autoimmunity it is plausible that targeting of Tregs by ICI immunotherapy results in the development of irAEs. Since the use of ICI becomes common, and new immune checkpoint molecules are currently under clinical trials for the treatment of cancer, the occurrence of irAEs is expected to dramatically rise. Herein we review the current literature focusing on the role of Tregs in cancer evolution, ICI response and development of irAEs. Unraveling the complex mechanisms that hinder the tumor immune surveillance and in particular how ICI immunotherapy imprint on Treg activities to promote cancer regression while avoid development of irAEs, will empower the design of novel immunotherapeutic modalities in cancer with increased efficacy and diminished adverse events.

Development of immune checkpoint therapy for cancer

Fritz and Lenardo discuss the basic science and clinical discoveries of immune checkpoint blockade, which boosts antitumor immunity and increases survival of patients with cancer.

Since the early 20th century, immunologists have investigated mechanisms that protect vertebrates from damaging immune responses against self-antigens by mature lymphocytes, i.e., peripheral tolerance. These mechanisms have been increasingly delineated at the molecular level, ultimately culminating in new therapeutics that have revolutionized clinical oncology. Here, we describe basic science and clinical discoveries that converge mainly on two molecules, CTLA-4 and PD-1, that were recognized with the 2018 Nobel Prize in Physiology or Medicine awarded to James Allison and Tasuku Honjo. We discuss their investigations and those of many others in the field that contravene tolerance through checkpoint inhibition to boost immune killing of malignant cells. We also discuss the mechanisms underlying each therapy, the efficacy achieved, and the complications of therapy. Finally, we hint at research questions for the future that could widen the success of cancer immunotherapy.

Immunotherapy and targeted therapies in older patients with advanced melanoma; Young International Society of Geriatric Oncology review paper

Malignant melanoma is an aggressive cancer associated with a poor prognosis in patients with metastatic disease. As in many other cancers, the incidence of melanoma rises with age; and combined with the longer life expectancy, this led to an increasing prevalence of melanoma in the older population. Recently, immune checkpoint inhibitors significantly improved the treatment of melanoma given their efficacy and tolerability profile. Two major classes of agents include the anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) inhibitors, such as ipilimumab, and the anti-programmed death-ligand 1 (PD-1) inhibitors, such as nivolumab and pembrolizumab. Treatment of metastatic disease with immune checkpoint inhibitors demonstrated improved efficacy and better safety profiles compared to cytotoxic drugs and appears to be an attractive treatment option. Nevertheless, there is a need for tools designed to better predict which older patients will benefit from its use and who will experience toxicities related to the treatment. Current data do not show a major increase in toxicity rates in older patients. However, patients above 75 are often under-represented and those who are included are not representative of the general population of older patients, thereby also stressing the need for real-life data. Ongoing research is aiming at maximizing the potential treatment efficacy and developing novel immune-targeting modalities. Future studies should include older patients and assess geriatric domains in these older patients to better guide decision-making. This review discusses published clinical trials and where known, the efficacy and toxicity in older patients. Moreover, the clinical implications and future perspectives are discussed, with current recommendations for older patients, management of toxicities, and a proposal for an initial approach to the treatment of older patients with metastatic melanoma.

Depleting T regulatory cells by targeting intracellular Foxp3 with a TCR mimic antibody

Depletion of T regulatory cells (Tregs) in the tumor microenvironment is a promising cancer immunotherapy strategy. Current approaches for depleting Tregs are limited by lack of specificity and concurrent depletion of anti-tumor effector T cells. The transcription factor forkhead box p3 (Foxp3) plays a central role in the development and function of Tregs and is an ideal target in Tregs, but Foxp3 is an intracellular, undruggable protein to date. We have generated a T cell receptor mimic antibody, "Foxp3-#32," recognizing a Foxp3-derived epitope in the context of HLA-A*02:01. The mAb Foxp3-#32 selectively recognizes CD4 + CD25 + CD127low and Foxp3 + Tregs also expressing HLA-A*02:01 and depletes these cells via antibody-mediated cellular cytotoxicity. Foxp3-#32 mAb depleted Tregs in xenografts of PBMCs from a healthy donor and ascites fluid from a cancer patient. A TCRm mAb targeting intracellular Foxp3 epitope represents an approach to deplete Tregs.

A review on the interactions between the tumor microenvironment and androgen receptor signaling in prostate cancer

Prostate cancer growth is controlled by androgen receptor signaling via both androgen-dependent and androgen-independent pathways. Furthermore, the prostate is an immune competent organ with inflammatory changes both within the systemic and local environment contributing to the reprogramming of the prostatic epithelium with consistently elevated lymphocyte infiltration and proinflammatory cytokines being found in prostate cancer. The crosstalk between the tumor microenvironment and androgen receptor signaling is complex with both protumorigenic and antitumorigenic roles observed. However, despite an increase in immune checkpoint inhibitors and inflammatory signaling blockades available for a range of cancer types, we are yet to see substantial progress in the treatment of prostate cancer. Therefore, this review aims to summarize the tumor microenvironment and its impact on androgen receptor signaling in prostate cancer.

Liquid Biopsies and Cancer Immunotherapy

Cancer immunotherapy has recently undergone rapid advances and has become an integral part of the treatment armamentarium in various malignancies. However, tissue-based biomarker development in this arena has been slow, and valid biomarker identification to guide immunotherapeutic management is desperately needed. "Liquid" or blood-based biopsies potentially offer more convenient and efficient means to judge the immune milieu of individual patients and identify who will benefit most from immunotherapy. The following review highlights the current literature regarding the application of liquid biopsies to cancer immunotherapy.

Tipping the balance: inhibitory checkpoints in intestinal homeostasis

The small intestinal and colonic lamina propria are populated with forkhead box P3 (FOXP3)⁺CD4⁺ regulatory T cells (Tregs) and interleukin-10-producing T cells that orchestrate intestinal tolerance to harmless microbial and food antigens. Expression of co-inhibitory receptors such as CTLA-4 and PD-1 serve as checkpoints to these cells controlling their T-cell receptor (TCR)-mediated and CD28-mediated activation and modulating the phenotype of neighboring antigen presenting cells. Recent discoveries on the diversity of co-inhibitory receptors and their selective cellular expression has shed new light on their tissue-dependent function. In this review, we provide an overview of the co-inhibitory pathways and checkpoints of Treg and effector T cells and their mechanisms of action in intestinal homeostasis. Better understanding of these inhibitory checkpoints is desired as their blockade harbors clinical potential for the treatment of cancer and their stimulation may offer new opportunities to treat chronic intestinal inflammation such as inflammatory bowel disease.

Cytokines, Chemokines, and Other Biomarkers of Response for Checkpoint Inhibitor Therapy in Skin Cancer

Immunotherapy for skin malignancies has ushered in a new era for cancer treatments by demonstrating unprecedented durable responses in the setting of metastatic Melanoma. Consequently, checkpoint inhibitors are now the first-line treatment of metastatic melanoma and widely used as adjuvant therapy for stage III disease. With the observation that higher tumor mutational burden correlates with a better response, checkpoint inhibitors are tested in other skin cancer types of known high tumor mutational burden with promising results and recently became the first-ever FDA-approved treatment for metastatic Merkel cell carcinoma. The emerging new standards-of-care will necessitate more precise biomarkers and predictors for treatment response and immune-related adverse events. Measurable immune-related mediators are currently under investigation as factors that promote or block the response to cancer immunotherapy and may provide insights into the underlying immune response to the tumor. Cytokines and chemokines are such mediators and are crucial for facilitating the recruitment and activation of specific subsets of leukocytes within the microenvironment of skin cancers. The exact mechanisms of how these meditators, both immunological and non-immunological, operate in the tumor microenvironment is an area of active research, so to reliable biomarkers of responses to cancer immunotherapy. Here, we will review and summarize the expanding body of literature for immune-related biomarkers pertaining to Melanoma, Basal cell carcinoma, Squamous cell carcinoma, and Merkel cell carcinoma, highlighting clinically relevant checkpoint inhibitor therapy biomarker advancements.

The application of nanotechnology in immune checkpoint blockade for cancer treatment

Cancer immunotherapy, which could utilize the host's immune system to kill tumor cells, has great potential in long-term inhibition of tumor growth and recurrence compared to chemotherapy and radiotherapy. As we know, tumors exhibit powerful adaption to escape the destruction of immune system at the late stage of diseases due to overactivation of immune checkpoint pathways which function as natural "brakes" for immune responses. The newly emerging immune checkpoint inhibitors are regarded as the breakthrough for cancer immunotherapy as they can re-boost the host's immune system by restoring T cells function and promoting cytotoxic T lymphocytes (CTLs) responses. However, there is still scope for improvement in enhancing the clinical efficacy and reducing side effects of these immune modulators. In this review, we mainly introduce the basic mechanisms of the immune checkpoint pathways and outline the recent successes of immune checkpoint blockade (ICB) therapy in combination with nanoparticle delivery system. Furthermore, the underexplored potential in application of nanotechnology to enhance the efficacy of immune checkpoint therapy and overcome the limits of immune checkpoint inhibitors is also discussed.

Complex interplay between tumor microenvironment and cancer therapy

Tumor microenvironment (TME) is comprised of cellular and non-cellular components that exist within and around the tumor mass. The TME is highly dynamic and its importance in different stages of cancer progression has been well recognized. A growing body of evidence suggests that TME also plays pivotal roles in cancer treatment responses. TME is significantly remodeled upon cancer therapies, and such change either enhances the responses or induces drug resistance. Given the importance of TME in tumor progression and therapy resistance, strategies that remodel TME to improve therapeutic responses are under developing. In this review, we provide an overview of the essential components in TME and the remodeling of TME in response to anti-cancer treatments. We also summarize the strategies that aim to enhance therapeutic efficacy by modulating TME.

Long term impact of CTLA4 blockade immunotherapy on regulatory and effector immune responses in patients with melanoma

Background

We previously reported early on-treatment significant modulation in circulating regulatory T cell (Treg), myeloid derived suppressor cells (MDSC) and antigen-specific type I CD4+ and CD8+ T cells that correlated with clinical outcome in regionally advanced melanoma patients treated with neoadjuvant ipilimumab. Here, we investigated the long term immunologic impact of CTLA4 blockade.

Methods

Patients were treated with ipilimumab given at 10 mg/kg IV every 3 weeks for 2 doses bracketing surgery. Blood specimens were collected at baseline and during treatment for up to 9 months. We tested immune responses at 3, 6, and 9 months utilizing multicolor flow cytometry. We compared frequencies of circulating Treg and MDSC on-study to baseline levels, as well as frequencies of CD4+ and CD8+ T cells specific to shared tumor-associated antigens (Gp-100, MART-1, NY-ESO-1).

Results

Levels of Treg significantly increased when measured at 6 weeks following ipilimumab but returned to baseline by 3 months, with no significant difference in Treg levels between relapsed and relapse-free groups at 3, 6 or 9 months. However, lower baseline levels of circulating Treg (CD4+CD25hi+CD39+) were significantly associated with better relapse free survival (RFS) (p = 0.04). Levels of circulating monocytic HLA-DR+/loCD14+ MDSC were lower at baseline in the relapse-free group and further decreased at 6 weeks, though the differences did not reach statistical significance including measurements at 3, 6 or 9 months. We detected evidence of type I (interferon-γ producing), activated (CD69+) CD4+ and CD8+ antigen-specific T cell immunity against cancer-testis (NY-ESO-1) as well as melanocytic lineage (MART-1, gp100) antigens in the absence of therapeutic vaccination. These responses were significantly boosted at 6 weeks and persisted at 3, 6 and 9 months following the initiation of ipilimumab.

Conclusions

Lower Treg levels at baseline are significantly associated with RFS and increased Treg frequency after CTLA4 blockade was only transient. Lower MDSC was also associated with RFS and MDSC levels were further decreased after ipilimumab. Tumor specific effector immune responses are boosted with CTLA4 blockade and tend to be durable.

Trial registration ClinicalTrials.gov Identifier: NCT00972933

Immune Profiling of Cancer Patients Treated with Immunotherapy: Advances and Challenges

The recent advances in immunotherapy and the availability of novel drugs to target the tumor microenvironment have dramatically changed the paradigm of cancer treatment. Nevertheless, a significant proportion of cancer patients are unresponsive or develop resistance to these treatments. With the aim to increase the clinical efficacy of immunotherapy, combinations of agents and standard therapies with complementary actions have been developed mostly on an empirical base, since their mechanisms of actions are not yet fully dissected. The characterization of immune responsiveness and its monitoring along with the treatment of cancer patients with immunotherapy can provide insights into the mechanisms of action of these therapeutic regimens and contribute to the optimization of patients’ stratification and of combination strategies and to the prediction of treatment-related toxicities. Thus far, none of the immunomonitoring strategies has been validated for routine clinical practice. Moreover, it is becoming clear that the genomic and molecular make-up of tumors and of the infiltrating immune system represent important determinants of the clinical responses to immunotherapy. This review provides an overview of different approaches for the immune profiling of cancer patients and discusses their advantages and limitations. Recent advances in genomic-based assays and in the identification of host genomic relationships with immune responses represent promising approaches to identify molecular determinants and biomarkers to improve the clinical efficacy of cancer immunotherapy.

Phosphoinositide 3-kinase δ inhibition promotes antitumor responses but antagonizes checkpoint inhibitors

Multiple modes of immunosuppression restrain immune function within tumors. We previously reported that phosphoinositide 3-kinase δ (PI3Kδ) inactivation in mice confers resistance to a range of tumor models by disrupting immunosuppression mediated by regulatory T cells (Tregs). The PI3Kδ inhibitor idelalisib has proven highly effective in the clinical treatment of chronic lymphocytic leukemia and the potential to extend the use of PI3Kδ inhibitors to nonhematological cancers is being evaluated. In this work, we demonstrate that the antitumor effect of PI3Kδ inactivation is primarily mediated through the disruption of Treg function, and correlates with tumor dependence on Treg immunosuppression. Compared with Treg-specific PI3Kδ deletion, systemic PI3Kδ inactivation is less effective at conferring resistance to tumors. We show that PI3Kδ deficiency impairs the maturation and reduces the capacity of CD8+ cytotoxic T lymphocytes (CTLs) to kill tumor cells in vitro, and to respond to tumor antigen-specific immunization in vivo. PI3Kδ inactivation antagonized the antitumor effects of tumor vaccines and checkpoint blockade therapies intended to boost the CD8+ T cell response. These findings provide insights into mechanisms by which PI3Kδ inhibition promotes antitumor immunity and demonstrate that the mechanism is distinct from that mediated by immune checkpoint blockade.

Histopathological and immunophenotypic features of ipilimumab-associated colitis compared to ulcerative colitis

BACKGROUND

Use of the immune checkpoint inhibitor ipilimumab is sometimes complicated by ipilimumab-associated colitis (Ipi-AC), an immune-mediated colitis that mimics inflammatory bowel disease.

OBJECTIVE

We sought to characterize the histopathologic and immunophenotypic features of Ipi-AC and to directly compare these features to ulcerative colitis (UC).

METHODS

This is a retrospective cohort study of 22 patients with Ipi-AC, 12 patients with treatment-naïve UC and five controls with diarrhoea but normal endoscopic findings. Immunohistopathologic features were described, and quantitative immunohistochemistry (IHC) was performed for CD4, CD8, CD20, CD138 and FOXP3.

RESULTS

Endoscopic findings in both the Ipi-AC and UC groups included ulcerated, oedematous and erythematous mucosa. Involvement of the GI tract was more diffuse in Ipi-AC. As compared to UC, a smaller proportion of Ipi-AC biopsies had basal plasmacytosis (14% for Ipi-AC vs. 92% for UC, P < 0.0001) and crypt distortion (23% for Ipi-AC vs. 75% for UC, P = 0.003), whereas Ipi-AC biopsies had more apoptotic bodies in the left colon (17.6 ± 15.3 for Ipi-AC vs. 8.2 ± 4.2 for UC, P = 0.011). Cryptitis, ulcerations and crypt abscesses were common in both groups. Biopsy specimens from Ipi-AC had a lower density of CD20-positive lymphocytes than UC (275.8 ± 253.3 cells mm-2 for Ipi-AC vs. 1173.3 ± 1158.2 cells mm-2 for UC, P = 0.022) but had a similar density of CD4, CD8, CD138 and FOXP3-positive cells.

CONCLUSIONS

Ipi-AC is a distinct pathologic entity with notable clinical and histopathological differences compared to UC. These findings provide insights into the pathophysiology of immune-related adverse events (iAEs) from ipilimumab therapy.

Uncoupling therapeutic from immunotherapy-related adverse effects for safer and effective anti-CTLA-4 antibodies in CTLA4 humanized mice

Anti-CTLA-4 monoclonal antibodies (mAbs) confer a cancer immunotherapeutic effect (CITE) but cause severe immunotherapy-related adverse events (irAE). Targeting CTLA-4 has shown remarkable long-term benefit and thus remains a valuable tool for cancer immunotherapy if the irAE can be brought under control. An animal model, which recapitulates clinical irAE and CITE, would be valuable for developing safer CTLA-4-targeting reagents. Here, we report such a model using mice harboring the humanized Ctla4 gene. In this model, the clinically used drug, Ipilimumab, induced severe irAE especially when combined with an anti-PD-1 antibody; whereas another mAb, L3D10, induced comparable CITE with very mild irAE under the same conditions. The irAE corresponded to systemic T cell activation and resulted in reduced ratios of regulatory to effector T cells (Treg/Teff) among autoreactive T cells. Using mice that were either homozygous or heterozygous for the human allele, we found that the irAE required bi-allelic engagement, while CITE only required monoallelic engagement. As with the immunological distinction for monoallelic vs bi-allelic engagement, we found that bi-allelic engagement of the Ctla4 gene was necessary for preventing conversion of autoreactive T cells into Treg cells. Humanization of L3D10, which led to loss of blocking activity, further increased safety without affecting the therapeutic effect. Taken together, our data demonstrate that complete CTLA-4 occupation, systemic T cell activation and preferential expansion of self-reactive T cells are dispensable for tumor rejection but correlate with irAE, while blocking B7-CTLA-4 interaction impacts neither safety nor efficacy of anti-CTLA-4 antibodies. These data provide important insights for the clinical development of safer and potentially more effective CTLA-4-targeting immunotherapy.