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

Treg Cell Therapeutic Strategies for Breast Cancer: Holistic to Local Aspects

Regulatory T cells (Tregs) play a key role in maintaining immune homeostasis and preventing autoimmunity through their immunosuppressive function. There have been numerous reports confirming that high levels of Tregs in the tumor microenvironment (TME) are associated with a poor prognosis, highlighting their role in promoting an immunosuppressive environment. In breast cancer (BC), Tregs interact with cancer cells, ultimately leading to the suppression of immune surveillance and promoting tumor progression. This review discusses the dual role of Tregs in breast cancer, and explores the controversies and therapeutic potential associated with targeting these cells. Researchers are investigating various strategies to deplete or inhibit Tregs, such as immune checkpoint inhibitors, cytokine antagonists, and metabolic inhibition. However, the heterogeneity of Tregs and the variable precision of treatments pose significant challenges. Understanding the functional diversity of Tregs and the latest advances in targeted therapies is critical for the development of effective therapies. This review highlights the latest approaches to Tregs for BC treatment that both attenuate Treg-mediated immunosuppression in tumors and maintain immune tolerance, and advocates precise combination therapy strategies to optimize breast cancer outcomes.

Linoleoyl-lysophosphatidylcholine suppresses immune-related adverse events due to immune checkpoint blockade

Immune related adverse events (irAEs) after immune checkpoint blockade (ICB) therapy occur in a significant proportion of cancer patients. To date, the circulating mediators of ICB-irAEs remain poorly understood. Using non-targeted mass spectrometry, here we identify the circulating bio-active lipid linoleoyl-lysophosphatidylcholine (LPC 18:2) as a modulator of ICB-irAEs. In three independent human studies of ICB treatment for solid tumor, loss of circulating LPC 18:2 preceded the development of severe irAEs across multiple organ systems. In both healthy humans and severe ICB-irAE patients, low LPC 18:2 was found to correlate with high blood neutrophilia. Reduced LPC 18:2 biosynthesis was confirmed in preclinical ICB-irAE models, and LPC 18:2 supplementation in vivo suppressed neutrophilia and tissue inflammation without impacting ICB anti-tumor response. Results indicate that circulating LPC 18:2 suppresses human ICB-irAEs, and LPC 18:2 supplementation may improve ICB outcomes by preventing severe inflammation while maintaining anti-tumor immunity.

Immune-related adverse events of antibody-based biological medicines in cancer therapy

Recombinant antibodies (Abs) are an integral modality for the treatment of multiple tumour malignancies. Since the Food and Drug Administration (FDA) approval of rituximab as the first monoclonal antibody (mAb) for cancer treatment, several mAbs and antibody (Ab)-based therapies have been approved for the treatment of solid tumour malignancies and other cancers. These Abs function by either blocking oncogenic pathways or angiogenesis, modulating immune response, or by delivering a conjugated drug. The use of Ab-based therapy in cancer patients who could benefit from the treatment, however, is still limited by associated toxicity profiles which may stem from biological features and processes related to target binding, alongside biochemical and/or biophysical characteristics of the therapeutic Ab. A significant immune-related adverse event (irAE) associated with Ab-based therapies is cytokine release syndrome (CRS), characterized by the development of fever, rash and even marked, life-threatening hypotension, and acute inflammation with secondary to systemic uncontrolled increase in a range of pro-inflammatory cytokines. Here, we review irAEs associated with specific classes of approved, Ab-based novel cancer immunotherapeutics, namely immune checkpoint (IC)-targeting Abs, bispecific Abs (BsAbs) and Ab-drug-conjugates (ADCs), highlighting the significance of harmonization in preclinical assay development for safety assessment of Ab-based biotherapeutics as an approach to support and refine clinical translation.

Artificial intelligence-powered discovery of small molecules inhibiting CTLA-4 in cancer

BACKGROUND/OBJECTIVES

Checkpoint inhibitors, which generate durable responses in many cancer patients, have revolutionized cancer immunotherapy. However, their therapeutic efficacy is limited, and immune-related adverse events are severe, especially for monoclonal antibody treatment directed against cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), which plays a pivotal role in preventing autoimmunity and fostering anticancer immunity by interacting with the B7 proteins CD80 and CD86. Small molecules impairing the CTLA-4/CD80 interaction have been developed; however, they directly target CD80, not CTLA-4.

SUBJECTS/METHODS

In this study, we performed artificial intelligence (AI)-powered virtual screening of approximately ten million compounds to identify those targeting CTLA-4. We validated the hits molecules with biochemical, biophysical, immunological, and experimental animal assays.

RESULTS

The primary hits obtained from the virtual screening were successfully validated in vitro and in vivo. We then optimized lead compounds and obtained inhibitors (inhibitory concentration, 1 micromole) that disrupted the CTLA-4/CD80 interaction without degrading CTLA-4.

CONCLUSIONS

Several compounds inhibited tumor development prophylactically and therapeutically in syngeneic and CTLA-4-humanized mice. Our findings support using AI-based frameworks to design small molecules targeting immune checkpoints for cancer therapy.

Standard Versus Modified Ipilimumab, in Combination With Nivolumab, in Advanced Renal Cell Carcinoma: A Randomized Phase II Trial (PRISM)

PURPOSE

Ipilimumab (IPI), in combination with nivolumab (NIVO), is an approved frontline treatment option for patients with intermediate- or poor-risk advanced renal cell carcinoma (aRCC). We conducted a randomized phase II trial to evaluate whether administering IPI once every 12 weeks (modified), instead of once every 3 weeks (standard), in combination with NIVO, is associated with a favorable toxicity profile.

METHODS

Treatment-naïve patients with clear-cell aRCC were randomly assigned 2:1 to receive four doses of modified or standard IPI, 1 mg/kg, in combination with NIVO (3 mg/kg). The primary end point was the proportion of patients with a grade 3-5 treatment-related adverse event (trAE) among those who received at least one dose of therapy. The key secondary end point was 12-month progression-free survival (PFS) in the modified arm compared with historical sunitinib control. The study was not designed to formally compare arms for efficacy.

RESULTS

Between March 2018 and January 2020, 192 patients (69.8% intermediate/poor-risk) were randomly assigned and received at least one dose of study drug. The incidence of grade 3-5 trAEs was significantly lower among participants receiving modified versus standard IPI (32.8% v 53.1%; odds ratio, 0.43 [90% CI, 0.25 to 0.72]; P = .0075). The 12-month PFS (90% CI) using modified IPI was 46.1% (38.6 to 53.2). At a median follow-up of 21 months, the overall response rate was 45.3% versus 35.9% and the median PFS was 10.8 months versus 9.8 months in the modified and standard IPI groups, respectively.

CONCLUSION

Rates of grade 3-5 trAEs were significantly lower in patients receiving modified versus standard IPI. Although 12-month PFS did not meet the prespecified efficacy threshold compared with historical control, informal comparison of treatment groups did not suggest any reduction in efficacy with the modified schedule.

Evaluation of regulatory T-cells in cancer immunotherapy: therapeutic relevance of immune checkpoint inhibition

The evolution of the complex immune system is equipped to defend against perilous intruders and concurrently negatively regulate the deleterious effect of immune-mediated inflammation caused by self and nonself antigens. Regulatory T-cells (Tregs) are specialized cells that minimize immune-mediated inflammation, but in malignancies, this feature has been exploited toward cancer progression by keeping the antitumor immune response in check. The modulation of Treg cell infiltration and their induction in the TME (tumor microenvironment) alongside associated inhibitory molecules, both soluble or membranes tethered in the TME, have proven clinically beneficial in boosting the tumoricidal activity of the immune system. Moreover, Treg-associated immune checkpoints pose a greater obstruction in cancer immunotherapy. Inhibiting or blocking active immune checkpoint signaling in combination with other therapies has proven clinically beneficial. This review summarizes the ontogeny of Treg cells and their migration, stability, and function in the TME. We also elucidate the Treg-associated checkpoint moieties that impede effective antitumor activity and harness these molecules for effective and targeted immunotherapy against cancer nuisance.

Pulmonary toxicity of immune checkpoint immunotherapy

Cancer remains a leading cause of mortality on a global scale. Lung cancer, specifically non-small cell lung cancer (NSCLC), is a prominent contributor to this burden. The management of NSCLC has advanced substantially in recent years, with immunotherapeutic agents, such as immune checkpoint inhibitors (ICIs), leading to improved patient outcomes. Although generally well tolerated, the administration of ICIs can result in unique side effects known as immune-related adverse events (irAEs). The occurrence of irAEs involving the lungs, specifically checkpoint inhibitor pneumonitis (CIP), can have a profound effect on both future therapy options and overall survival. Despite CIP being one of the more common serious irAEs, limited treatment options are currently available, in part due to a lack of understanding of the underlying mechanisms involved in its development. In this Review, we aim to provide an overview of the epidemiology and clinical characteristics of CIP, followed by an examination of the emerging literature on the pathobiology of this condition.

Preclinical Modeling of Pathway-Targeted Therapy of Human Lung Cancer in the Mouse

Animal models, particularly genetically engineered mouse models (GEMMs), continue to have a transformative impact on our understanding of the initiation and progression of hematological malignancies and solid tumors. Furthermore, GEMMs have been employed in the design and optimization of potent anticancer therapies. Increasingly, drug responses are assessed in mouse models either prior, or in parallel, to the implementation of precision medical oncology, in which groups of patients with genetically stratified cancers are treated with drugs that target the relevant oncoprotein such that mechanisms of drug sensitivity or resistance may be identified. Subsequently, this has led to the design and preclinical testing of combination therapies designed to forestall the onset of drug resistance. Indeed, mouse models of human lung cancer represent a paradigm for how a wide variety of GEMMs, driven by a variety of oncogenic drivers, have been generated to study initiation, progression, and maintenance of this disease as well as response to drugs. These studies have now expanded beyond targeted therapy to include immunotherapy. We highlight key aspects of the relationship between mouse models and the evolution of therapeutic approaches, including oncogene-targeted therapies, immunotherapies, acquired drug resistance, and ways in which successful antitumor strategies improve on efficiently translating preclinical approaches into successful antitumor strategies in patients.

Engineering Probiotic E. coli Nissle 1917 for Release of Therapeutic Nanobodies

Bioengineered probiotics enable new opportunities to improve cancer treatment strategies due to their tumor-colonizing capabilities. Here, we will describe the development of a probiotic E. coli Nissle 1917 platform encoding a synchronized lysis mechanism for the localized and sustained release of blocking nanobodies against immune checkpoint molecules like programmed cell death protein-ligand 1 and cytotoxic T lymphocyte-associated protein-4. Specifically, we will detail the experimental protocols needed to (1) encode and validate binding of recombinantly produced checkpoint blockade nanobodies, (2) evaluate the therapeutic efficacy and safety of the probiotic platform in syngeneic tumor-bearing mice, and (3) analyze the immunophenotype of the tumor microenvironment.

Biomarkers and experimental models for cancer immunology investigation

The rapid advancement of tumor immunotherapies poses challenges for the tools used in cancer immunology research, highlighting the need for highly effective biomarkers and reproducible experimental models. Current immunotherapy biomarkers encompass surface protein markers such as PD-L1, genetic features such as microsatellite instability, tumor-infiltrating lymphocytes, and biomarkers in liquid biopsy such as circulating tumor DNAs. Experimental models, ranging from 3D in vitro cultures (spheroids, submerged models, air-liquid interface models, organ-on-a-chips) to advanced 3D bioprinting techniques, have emerged as valuable platforms for cancer immunology investigations and immunotherapy biomarker research. By preserving native immune components or coculturing with exogenous immune cells, these models replicate the tumor microenvironment in vitro. Animal models like syngeneic models, genetically engineered models, and patient-derived xenografts provide opportunities to study in vivo tumor-immune interactions. Humanized animal models further enable the simulation of the human-specific tumor microenvironment. Here, we provide a comprehensive overview of the advantages, limitations, and prospects of different biomarkers and experimental models, specifically focusing on the role of biomarkers in predicting immunotherapy outcomes and the ability of experimental models to replicate the tumor microenvironment. By integrating cutting-edge biomarkers and experimental models, this review serves as a valuable resource for accessing the forefront of cancer immunology investigation.

Genetic and pharmaceutical targeting of HIF1α allows combo-immunotherapy to boost graft vs. leukemia without exacerbation graft vs. host disease

Despite potential impact on the graft vs. leukemia (GVL) effect, immunotherapy targeting CTLA-4 and/or PD-1 has not been successfully combined with bone marrow transplant (BMT) because it exacerbates graft vs. host disease (GVHD). Here, using models of GVHD and leukemia, we demonstrate that targeting hypoxia-inducible factor 1α (HIF1α) via pharmacological or genetic approaches reduces GVHD by inducing PDL1 expression on host tissue while selectively inhibiting PDL1 in leukemia cells to enhance the GVL effect. More importantly, combination of HIF1α inhibition with anti-CTLA-4 antibodies allows simultaneous inhibition of both PDL1 and CTLA-4 checkpoints to achieve better outcomes in models of mouse and human BMT-leukemia settings. These findings provide an approach to enhance the curative effect of BMT for leukemia and broaden the impact of cancer immunotherapy.

Regulating the regulatory T cells as cell therapies in autoimmunity and cancer

Regulatory T cells (Tregs), possess a pivotal function in the maintenance of immune homeostasis. The dysregulated activity of Tregs has been associated with the onset of autoimmune diseases and cancer. Hence, Tregs are promising targets for interventions aimed at steering the immune response toward the desired path, either by augmenting the immune system to eliminate infected and cancerous cells or by dampening it to curtail the damage to self-tissues in autoimmune disorders. The activation of Tregs has been observed to have a potent immunosuppressive effect against T cells that respond to self-antigens, thus safeguarding our body against autoimmunity. Therefore, promoting Treg cell stability presents a promising strategy for preventing or managing chronic inflammation that results from various autoimmune diseases. On the other hand, Tregs have been found to be overactivated in several forms of cancer, and their role as immune response regulators with immunosuppressive properties poses a significant impediment to the successful implementation of cancer immunotherapy. However, the targeting of Tregs in a systemic manner may lead to the onset of severe inflammation and autoimmune toxicity. It is imperative to develop more selective methods for targeting the function of Tregs in tumors. In this review, our objective is to elucidate the function of Tregs in tumors and autoimmunity while also delving into numerous therapeutic strategies for reprogramming their function. Our focus is on reprogramming Tregs in a highly activated phenotype driven by the activation of key surface receptors and metabolic reprogramming. Furthermore, we examine Treg-based therapies in autoimmunity, with a specific emphasis on Chimeric Antigen Receptor (CAR)-Treg therapy and T-cell receptor (TCR)-Treg therapy. Finally, we discuss key challenges and the future steps in reprogramming Tregs that could lead to the development of novel and effective cancer immunotherapies.

Stocking the toolbox-Using preclinical models to understand the development and treatment of immune checkpoint inhibitor-induced immune-related adverse events

Cancer patients treated with immune checkpoint inhibitors (ICIs) are susceptible to a broad and variable array of immune-related adverse events (irAEs). With increasing clinical use of ICIs, defining the mechanism for irAE development is more critical than ever. However, it currently remains challenging to predict when these irAEs occur and which organ may be affected, and for many of the more severe irAEs, inaccessibility to the tissue site hampers mechanistic insight. This lack of understanding of irAE development in the clinical setting emphasizes the need for greater use of preclinical models that allow for improved prediction of biomarkers for ICI-initiated irAEs or that validate treatment options that inhibit irAEs without hampering the anti-tumor immune response. Here, we discuss the utility of preclinical models, ranging from exploring databases to in vivo animal models, focusing on where they are most useful and where they could be improved.

CD24-Siglec interactions in inflammatory diseases

CD24 is a small glycosylphosphatidylinositol (GPI)-anchored glycoprotein with broad expression in multiple cell types. Due to differential glycosylation, cell surface CD24 have been shown to interact with various receptors to mediate multiple physiological functions. Nearly 15 years ago, CD24 was shown to interact with Siglec G/10 to selectively inhibit inflammatory response to tissue injuries. Subsequent studies demonstrate that sialylated CD24 (SialoCD24) is a major endogenous ligand for CD33-family of Siglecs to protect the host against inflammatory and autoimmune diseases, metabolic disorders and most notably respiratory distress in COVID-19. The discoveries on CD24-Siglec interactions propelled active translational research to treat graft-vs-host diseases, cancer, COVID-19 and metabolic disorders. This mini-review provides a succinct summary on biological significance of CD24-Siglec pathway in regulation of inflammatory diseases with emphasis on clinical translation.

HX009, a novel BsAb dual targeting PD1 x CD47, demonstrates potent anti-lymphoma activity in preclinical models

Both PD1/PD-L1 and CD47 blockades have demonstrated limited activity in most subtypes of NHL save NK/T-cell lymphoma. The hemotoxicity with anti-CD47 agents in the clinic has been speculated to account for their limitations. Herein we describe a first-in-class and rationally designed bispecific antibody (BsAb), HX009, targeting PD1 and CD47 but with weakened CD47 binding, which selectively hones the BsAb for tumor microenvironment through PD1 interaction, potentially reducing toxicity. In vitro characterization confirmed: (1) Both receptor binding/ligand blockade, with lowered CD47 affinity; (2) functional PD1/CD47 blockades by reporter assays; (3) T-cell activation in Staphylococcal-enterotoxin-B-pretreated PBMC and mixed-lymphocyte-reaction. In vivo modeling demonstrated antitumor activity in Raji-B and Karpass-229-T xenograft lymphomas. In the humanized mouse syngeneic A20 B-lymphoma (huCD47-A20) HuGEMM model, which has quadruple knocked-in hPD1xhPD-L1xhCD47xhSIRPα genes and an intact autologous immune-system, a contribution of effect is demonstrated for each targeted biologic (HX008 targeting PD1 and SIRPα-Fc targeting CD47), which is clearly augmented by the dual targeting with HX009. Lastly, the expression of the immune-checkpoints PD-L1/L2 and CD47 seemed co-regulated among a panel of lymphoma-derived-xenografts, where HX009 maybe more effective in those with upregulated CD47. Our data warrants HX009's further clinical development for treating NHLs.

Active recruitment of anti-PD-1-conjugated platelets through tumor-selective thrombosis for enhanced anticancer immunotherapy

Immune checkpoint inhibitors (ICIs) can reinvigorate T cells to eradicate tumor cells, showing great potential in combating various types of tumors. We propose a delivery strategy to enhance tumor-selective ICI accumulation, which leverages the responsiveness of platelets and platelet-derivatives to coagulation cascade signals. A fused protein tTF-RGD targets tumor angiogenic blood vessel endothelial cells and initiates the coagulation locoregionally at the tumor site, forming a "cellular hive" to recruit anti-PD-1 antibody (aPD-1)-conjugated platelets to the tumor site and subsequently activating platelets to release aPD-1 antibody to reactivate T cells for improved immunotherapy. Moreover, on a patient-derived xenograft breast cancer model, the platelet membrane-coated nanoparticles can also respond to the coagulation signals initiated by tTF-RGD, thus enhancing the accumulation and antitumor efficacy of the loaded chemotherapeutics. Our study illustrates a versatile platform technology to enhance the local accumulation of ICIs and chemodrugs by taking advantage of the responsiveness of platelets and platelet derivatives to thrombosis.

Oral Delivery of Therapeutic Antibodies with a Transmucosal Polymeric Carrier

Therapeutic proteins are playing increasingly important roles in treating numerous types of diseases. However, oral administration of proteins, especially large ones (e.g., antibodies), remains a great challenge due to their difficulties in penetrating intestinal barriers. Herein, fluorocarbon-modified chitosan (FCS) is developed for efficient oral delivery of different therapeutic proteins, in particular large ones such as immune checkpoint blockade antibodies. In our design, therapeutic proteins are mixed with FCS to form nanoparticles, lyophilized with appropriate excipients, and then filled into enteric capsules for oral administration. It has been found that FCS could promote transmucosal delivery of its cargo protein via inducing transitory rearrangement of tight junction associated proteins between intestinal epithelial cells and subsequently release free proteins into blood circulation. It is shown that at a 5-fold dose oral delivery of anti-programmed cell death protein-1 (αPD1) or its combination with anti-cytotoxic T-lymphocyte antigen 4 (αCTLA4) using this method could achieve comparable antitumor therapeutic responses to that achieved by intravenous injection of corresponding free antibodies in various types of tumor models and, more excitingly, result in significantly reduced immune-related adverse events. Our work successfully demonstrates the enhanced oral delivery of antibody drugs to achieve systemic therapeutic responses and may revolutionize the future clinical usage of protein therapeutics.

Chemokine Receptors CCR6 and PD1 Blocking scFv E27 Enhances Anti-EGFR CAR-T Therapeutic Efficacy in a Preclinical Model of Human Non-Small Cell Lung Carcinoma

Chimeric antigen receptor (CAR)-T cells, a therapeutic agent for solid tumors, are not completely effective due to a lack of infiltration of T cells into the tumor site and immunity caused by Programmed Death Receptor 1(PD1). Here, an epidermal growth factor receptor (EGFR) CAR-T cell was engineered to express the chemokine receptor CCR6 and secrete PD1 blocking Single-chain antibody fragment (scFv) E27 to enhance their anti-tumor effects. The findings showed that CCR6 enhanced the migration of EGFR CAR-E27-CCR6 T cells in vitro by the Transwell migration assay. When incubated with tumor cells, EGFR CAR-E27-CCR6 T cells specifically exerted potent cytotoxicity and produced high levels of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-2 (IL-2), and interferon-γ (IFN-γ). A non-small cell lung carcinoma (NSCLC) cell line-derived xenograft model was constructed by implanting modified A549 cell lines into immunodeficient NOD.PrkdcscidIl2rgem1/Smoc (NSG) mice. In comparison with traditional EGFR CAR-T cells, live imaging indicated that EGFR CAR-E27-CCR6 T cells displayed superior anti-tumor function. In addition, the histopathological examination of mouse organs showed no obvious organic damage. Our findings confirmed that PD1 blocking and CCR6 can enhance the anti-tumor function of EGFR CAR-T cells in an NSCLC xenograft model, providing an effective treatment strategy to improve the efficacy of CAR-T in NSCLC.

Soluble CTLA-4 mutants ameliorate immune-related adverse events but preserve efficacy of CTLA-4- and PD-1-targeted immunotherapy

Immune checkpoint inhibitors (ICIs), such as nivolumab and ipilimumab, not only elicit antitumor responses in a wide range of human cancers but also cause severe immune-related adverse events (irAEs), including death. A largely unmet medical need is to treat irAEs without abrogating the immunotherapeutic effect of ICIs. Although abatacept has been used to treat irAEs, it risks neutralizing the anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) monoclonal antibodies administered for cancer therapy, thereby reducing the efficacy of anti-CTLA-4 immunotherapy. To avoid this caveat, we compared wild-type abatacept and mutants of CTLA-4-Ig for their binding to clinically approved anti-CTLA-4 antibodies and for their effect on both irAEs and immunotherapy conferred by anti-CTLA-4 and anti-PD-1 antibodies. Here, we report that whereas abatacept neutralized the therapeutic effect of anti-CTLA-4 antibodies, the mutants that bound to B7-1 and B7-2, but not to clinical anti-CTLA-4 antibodies, including clinically used belatacept, abrogated irAEs without affecting cancer immunotherapy. Our data demonstrate that anti-CTLA-4-induced irAEs can be corrected by provision of soluble CTLA-4 variants and that the clinically available belatacept may emerge as a broadly applicable drug to abrogate irAEs while preserving the therapeutic efficacy of CTLA-4-targeting ICIs.

Characterization of the high-affinity anti-CTLA-4 monoclonal antibody JS007 for immune checkpoint therapy of cancer

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a critical inhibitory checkpoint molecule, and monoclonal antibodies (mAbs) targeting CTLA-4 that restore anti-tumor T cell immunity have achieved clinical success. Here, we report a humanized IgG1 mAb, namely JS007, with high binding affinity to CTLA-4. JS007 shows superior binding affinity and T-cell activating efficiency over ipilimumab. Moreover, it demonstrates substantial in vivo tumor suppression efficacy at low doses. The crystal structure of JS007/CTLA-4 complex (PDB: 8HIT) shows JS007 adopts a heavy-chain-dominant binding mode, and mainly contacts the BC loop, DE loop and FG loop of CTLA-4. Notably, two Tyr residues (VH-Y100 and VL-Y32) from the complementarity-determining region loops insert into the two cavities formed by the residues from the loops of CTLA-4, which may contribute to the stabilization of the binding. Comparative analysis with other anti-CTLA-4 mAbs indicates that the double "wedge-into-hole" binding mode is unique for JS007 and may be responsible for the high-affinity binding to CTLA-4. These findings have provided an important molecular understanding of the high-affinity CTLA-4 blockade mAbs and shed light on future development of agents targeting CTLA-4.

Signaling pathways and targeted therapies in lung squamous cell carcinoma: mechanisms and clinical trials

Lung cancer is the leading cause of cancer-related death across the world. Unlike lung adenocarcinoma, patients with lung squamous cell carcinoma (LSCC) have not benefitted from targeted therapies. Although immunotherapy has significantly improved cancer patients' outcomes, the relatively low response rate and severe adverse events hinder the clinical application of this promising treatment in LSCC. Therefore, it is of vital importance to have a better understanding of the mechanisms underlying the pathogenesis of LSCC as well as the inner connection among different signaling pathways, which will surely provide opportunities for more effective therapeutic interventions for LSCC. In this review, new insights were given about classical signaling pathways which have been proved in other cancer types but not in LSCC, including PI3K signaling pathway, VEGF/VEGFR signaling, and CDK4/6 pathway. Other signaling pathways which may have therapeutic potentials in LSCC were also discussed, including the FGFR1 pathway, EGFR pathway, and KEAP1/NRF2 pathway. Next, chromosome 3q, which harbors two key squamous differentiation markers SOX2 and TP63 is discussed as well as its related potential therapeutic targets. We also provided some progress of LSCC in epigenetic therapies and immune checkpoints blockade (ICB) therapies. Subsequently, we outlined some combination strategies of ICB therapies and other targeted therapies. Finally, prospects and challenges were given related to the exploration and application of novel therapeutic strategies for LSCC.

Pathophysiology of Immune Checkpoint Inhibitor-Induced Myocarditis

Immune checkpoint inhibitors (ICIs) have recently emerged as strong therapies for a broad spectrum of cancers being the first-line treatment for many of them, even improving the prognosis of malignancies that were considered untreatable. This therapy is based on the administration of monoclonal antibodies targeting inhibitory T-cell receptors, which boost the immune system and prevent immune evasion. However, non-specific T-cell de-repression can result in a wide variety of immune-related adverse events (irAEs), including gastrointestinal, endocrine, and dermatologic, with a smaller proportion of these having the potential for fatal outcomes such as neurotoxicity, pulmonary toxicity, and cardiotoxicity. In recent years, alarm has been raised about cardiotoxicity as it has the highest mortality rate when myocarditis develops. However, due to the difficulty in diagnosing this cardiac condition and the lack of clinical guidelines for the management of cardiovascular disease in patients on therapy with ICIs, early detection of myocarditis has become a challenge in these patients. In this review we outline the mechanisms of tolerance by which this fatal cardiomyopathy may develop in selected cancer patients treated with ICIs, summarize preclinical models of the disease that will allow the development of more accurate strategies for its detection and treatment, and discuss the challenges in the future to decrease the risks of its development with better decision making in susceptible patients.

Lkb1 aggravates diffuse large B-cell lymphoma by promoting the function of Treg cells and immune escape

Background

Regulatory T cells (Tregs) induce immune responses and may contribute to immune escape in tumors. Accumulation of Tregs in tumors represents a critical barrier to anti-tumor immunity and immunotherapy. However, conflicting results describing the role of Tregs in lymphoma warrant further investigation. The precise features and mechanisms underlying the alteration in Tregs in diffuse large B-cell lymphoma (DLBCL) are not well understood yet. In this study, we analyzed the mechanism underlying the observed alterations in Tregs in DLBCL and examined the effect of Lkb1 expression on the immunosuppressive function of human Tregs.

Methods

Flow cytometry and immunofluorescence were used to analyze the proportion of Tregs and effector Tregs in the peripheral blood and lymph nodes of patients with DLBCL and control group. In vitro culture assays were used to analyze the immunosuppressive function of Tregs in the two groups. Transcriptome sequencing was performed to analyze the differentially expressed genes in the two groups, and the transcription level and protein expression of Lkb1 in the two groups were detected using RT-PCR and WES microprotein technology. Lentiviral vectors were constructed to explore the functional changes of Tregs with stable upregulation and downregulation of Lkb1. Finally, a humanized murine lymphoma model was established to study the function of Lkb1 in Tregs in the pathogenesis of DLBCL.

Results

The number of Tregs was found to be dramatically increased in peripheral blood and tumor tissue in DLBCL patients compared with that in healthy controls, and decreased after treatment. Tregs from DLBCL patients exhibited multiple enhanced functions, including increased inhibition of CD8⁺cytotoxic T cells (CTL) against tumor cells, enhanced suppression of CD8⁺CTL secretion of granular enzyme, and suppression of CD8⁺CTL degranulation. Lkb1 was found to be upregulated in Tregs of DLBCL patients. Furthermore, Lkb1 contributes to Treg immunosuppressive function in DLBCL by regulating the mevalonate pathway. Finally, deletion of Lkb1 in Tregs suppressed tumor growth and promoted anti-tumor immunity in a DLBCL murine model.

Conclusions

These findings confirmed that Lkb1-regulated Tregs are critical for immune escape in DLBCL, which emphasizes that Lkb1 is a potential target for the immunotherapy of DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03588-0.

Mouse Models for Immune Checkpoint Blockade Therapeutic Research in Oral Cancer

The most prevalent oral cancer globally is oral squamous cell carcinoma (OSCC). The invasion of adjacent bones and the metastasis to regional lymph nodes often lead to poor prognoses and shortened survival times in patients with OSCC. Encouraging immunotherapeutic responses have been seen with immune checkpoint inhibitors (ICIs); however, these positive responses to monotherapy have been limited to a small subset of patients. Therefore, it is urgent that further investigations into optimizing immunotherapies are conducted. Areas of research include identifying novel immune checkpoints and targets and tailoring treatment programs to meet the needs of individual patients. Furthermore, the advancement of combination therapies against OSCC is also critical. Thus, additional studies are needed to ensure clinical trials are successful. Mice models are advantageous in immunotherapy research with several advantages, such as relatively low costs and high tumor growth success rate. This review paper divided methods for establishing OSCC mouse models into four categories: syngeneic tumor models, chemical carcinogen induction, genetically engineered mouse, and humanized mouse. Each method has advantages and disadvantages that influence its application in OSCC research. This review comprehensively surveys the literature and summarizes the current mouse models used in immunotherapy, their advantages and disadvantages, and details relating to the cell lines for oral cancer growth. This review aims to present evidence and considerations for choosing a suitable model establishment method to investigate the early diagnosis, clinical treatment, and related pathogenesis of OSCC.

Inhibition of IL-17A Protects against Thyroid Immune-Related Adverse Events while Preserving Checkpoint Inhibitor Antitumor Efficacy

Immune checkpoint inhibitor (ICI) immunotherapy leverages the body's own immune system to attack cancer cells but leads to unwanted autoimmune side effects in up to 60% of patients. Such immune-related adverse events (IrAEs) may lead to treatment interruption, permanent organ dysfunction, hospitalization, and premature death. Thyroiditis is one of the most common IrAEs, but the cause of thyroid IrAEs remains unknown. In this study, we use a new, physiologically relevant mouse model of ICI-associated autoimmunity to identify a key role for type 3 immune cells in the development of thyroid IrAEs. Multiple lineages of IL-17A-producing T cells expand in thyroid tissue with ICI treatment. Intrathyroidal IL-17A-producing innate-like γδT17 cells were increased in tumor-free mice, whereas adaptive Th17 cells were also prominent in tumor-bearing mice, following ICI treatment. Furthermore, Ab-based inhibition of IL-17A, a clinically available therapy, significantly reduced thyroid IrAE development in ICI-treated mice with and without tumor challenge. Finally, combination of IL-17A neutralization with ICI treatment in multiple tumor models did not reduce ICI antitumor efficacy. These studies suggest that targeting Th17 and γδT17 cell function via the IL-17A axis may reduce IrAEs without impairing ICI antitumor efficacy and may be a generalizable strategy to address type 3 immune-mediated IrAEs.

Patient-derived cancer models: Valuable platforms for anticancer drug testing

Molecularly targeted treatments and immunotherapy are cornerstones in oncology, with demonstrated efficacy across different tumor types. Nevertheless, the overwhelming majority metastatic disease is incurable due to the onset of drug resistance. Preclinical models including genetically engineered mouse models, patient-derived xenografts and two- and three-dimensional cell cultures have emerged as a useful resource to study mechanisms of cancer progression and predict efficacy of anticancer drugs. However, variables including tumor heterogeneity and the complexities of the microenvironment can impair the faithfulness of these platforms. Here, we will discuss advantages and limitations of these preclinical models, their applicability for drug testing and in co-clinical trials and potential strategies to increase their reliability in predicting responsiveness to anticancer medications.

TNF-α inhibitor ameliorates immune-related arthritis and pneumonitis in humanized mice

Objectives

This study aimed at establishing a mouse model of immune-related adverse in humanized BALB/c-hPD1/hCTLA4 mice to investigate their potential pathogenesis and explore therapeutic targets for immune-related arthritis and pneumonitis.

Methods

Humanized BALB/c-hPD1/hCTLA4 mice were injected with vehicle or collagen-specific antibodies (CA) and immune checkpoint inhibitors (ICI, ipilimumab, anti-human CTLA-4; and nivolumab, anti-human PD-1), and some mice were treated with anti-TNF-α antibody, leading to the control, collagen antibody-induced arthritis (CAIA), CAIA+ICI and treatment groups. The severity of clinical arthritis and pneumonitis in mice was monitored longitudinally and the pathological changes in the joints and lungs were histologically analyzed and the contents of lung hydroxyproline were measured. The frequency of different subsets of T cells was analyzed by flow cytometry and multiplex immunofluorescency.

Results

Compared with the control, the ICI group of mice developed the delayed onset of moderate degrees of arthritis while the CAIA+ICI group of mice exhibited the early onset of severe arthritis. Treatment with ICI caused severe pneumonitis, especially in the mice with CA. Flow cytometry analysis indicated a significantly higher frequency of splenic TNF-α+CD4+ and TNF-α+CD8+ T cells, but not other subsets of T cells tested, in the CAIA+ICI group of mice, relative to that in other groups of mice. Treatment with anti-TNF-α significantly mitigated the severity of arthritis and pneumonitis as well as deposition of collagen in lung of mice. The treatment also decreased the frequency of TNF-α+CD4+ and TNF-α+CD8+ T cells as well as effector memory T cells in the periphery lymph orangs and lungs of mice.

Conclusions

We successfully established a humanized mouse model of ICI-related severe arthritis and pneumonitis with a higher frequency of TNF-α+ T cells, which were significantly mitigated by anti-TNF-α treatment. Conceptually, ICI treatment can induce multiple autoimmune-like diseases in autoimmune-prone individuals and TNF-α+ T cells may be therapeutic targets for intervention of immune-related arthritis and pneumonitis.

Glycoengineered anti-CD39 promotes anticancer responses by depleting suppressive cells and inhibiting angiogenesis in tumor models

Immunosuppressive cells accumulating in the tumor microenvironment constitute a formidable barrier that interferes with current immunotherapeutic approaches. A unifying feature of these tumor-associated immune and vascular endothelial cells appears to be the elevated expression of ectonucleotidase CD39, which in tandem with ecto-5'-nucleotidase CD73, catalyzes the conversion of extracellular ATP into adenosine. We glycoengineered an afucosylated anti-CD39 IgG2c and tested this reagent in mouse melanoma and colorectal tumor models. We identified major biological effects of this approach on cancer growth, associated with depletion of immunosuppressive cells, mediated through enhanced Fcγ receptor-directed (FcγR-directed), antibody-dependent cellular cytotoxicity (ADCC). Furthermore, regulatory/exhausted T cells lost CD39 expression, as a consequence of antibody-mediated trogocytosis. Most strikingly, tumor-associated macrophages and endothelial cells with high CD39 expression were effectively depleted following antibody treatment, thereby blocking angiogenesis. Tumor site-specific cellular modulation and lack of angiogenesis synergized with chemotherapy and anti-PD-L1 immunotherapy in experimental tumor models. We conclude that depleting suppressive cells and targeting tumor vasculature, through administration of afucosylated anti-CD39 antibody and the activation of ADCC, comprises an improved, purinergic system-modulating strategy for cancer therapy.

Prognostic significance of CD8+ tumor‑infiltrating lymphocytes and CD66b+ tumor‑associated neutrophils in the invasive margins of stages I‑III colorectal cancer

Tumor-infiltrating immune cells play an essential role in cancer progression and may help supplement the Tumor, Node, Metastasis (TNM) classification for cancer prognosis. Currently, there are numerous conflicting reports discussing the significance of tumor-associated neutrophils (TANs) in colorectal cancer (CRC). In particular, the role of TANs in the invasive margin is unclear. The present study investigated the prognostic significance of CD66⁺ TANs and CD8⁺ tumor-infiltrating lymphocytes (TILs) in the invasive margin of 103 patients with CRC. By using immunohistochemistry, survival analysis was performed on CD8⁺ TILs and CD66⁺ TANs individually, as well as models including TILs and TANs simultaneously. The findings indicated that the densities of CD8⁺ TILs and CD66b⁺ TANs in the invasive margin may provide significant prognostic value for predicting survival. Moreover, the combined evaluation of CD8⁺ TILs and CD66b⁺ TANs in the invasive margin could further improve the validity for the prediction of oncological outcomes. In addition, multivariate analysis revealed that simultaneous low tumor infiltration by CD8⁺ TILs and CD66b⁺ was an independent predictive factor for overall survival (HR=4.17, 95% CI, 1.55-12.5; P=0.004) and disease-free survival (HR=2.75, 95% CI, 1.27-6.12; P=0.01). Given the importance of CD8⁺ TILs and CD66b⁺ TANs in the tumor microenvironment, the assessment of their densities in the invasive margin may serve as a valuable prognostic marker for CRC.

Resistance Mechanisms to Anti-PD Cancer Immunotherapy

The transformative success of antibodies targeting the PD-1 (programmed death 1)/B7-H1 (B7 homolog 1) pathway (anti-PD therapy) has revolutionized cancer treatment. However, only a fraction of patients with solid tumors and some hematopoietic malignancies respond to anti-PD therapy, and the reason for failure in other patients is less known. By dissecting the mechanisms underlying this resistance, current studies reveal that the tumor microenvironment is a major location for resistance to occur. Furthermore, the resistance mechanisms appear to be highly heterogeneous. Here, we discuss recent human cancer data identifying mechanisms of resistance to anti-PD therapy. We review evidence for immune-based resistance mechanisms such as loss of neoantigens, defects in antigen presentation and interferon signaling, immune inhibitory molecules, and exclusion of T cells. We also review the clinical evidence for emerging mechanisms of resistance to anti-PD therapy, such as alterations in metabolism, microbiota, and epigenetics. Finally, we discuss strategies to overcome anti-PD therapy resistance and emphasize the need to develop additional immunotherapies based on the concept of normalization cancer immunotherapy.

PD-L1 siRNA-hyaluronic acid conjugate for dual-targeted cancer immunotherapy

"Foreignization" of tumor cells via delivery of a non-self foreign antigen (Ag) into tumors is an appealing strategy to initiate anti-tumor immunity that can facilitate tumor rejection by pre-existing foreign-Ag-reactive T cells. However, the immune-suppressive factors in the tumor microenvironment (TME) limit the durable and potent immune response of these cells against tumor antigens, stressing the need for improved tumor-foreignization strategies. Here, we demonstrate that blockade of programmed cell death ligand 1 (PD-L1) on both tumor cells and dendritic cells (DCs) can markedly potentiate the induction of tumor-reactive T cells, thereby strengthening the anti-tumor immunity ignited by tumor-foreignization. Specifically, we developed a polymeric nanoconjugate (PEG-HA-OVA/PPLs), consisting of siPD-L1-based polyplexes, PEGylated hyaluronic acid as the CD44-targeting moiety, and ovalbumin (OVA) as a model foreign antigen. Notably, PEG-HA-OVA/PPLs were simultaneously delivered into CD44^high tumor cells and CD44^high DCs, leading to efficient cross-presentation of OVA and downregulation of PD-L1 in both cell types. Importantly, the nanoconjugate not only allowed OVA-specific T cells to vigorously reject the foreignized tumor cells but also reprogrammed the TME to elicit robust T-cell responses specific to the endogenous tumor Ags, eventually generating long-lasting protective immunity. Thus, our combination strategy represents an innovative approach for the induction of potent tumor immunity via a two-step consecutive immune boost against exogenous and endogenous tumor Ags.

Balancing the good and the bad: controlling immune related adverse events versus anti-tumor responses in cancer patients treated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have provided new hope for cancer patients, and in particular for patients with tumors that are immunologically active and classified as hot tumors. These tumors express antigenic and tumor microenvironment (TME) characteristics that make them potential candidates for therapy with checkpoint inhibitors that aim to reactivate the immune response such as anti-PD-1 and anti-CTLA-4. Examples of potentially responsive cancers are, melanoma, non-small cell lung cancer and several other metastatic or unresectable tumors with genetic instability: DNA mismatch repair deficiency (dMMR), microsatellite instability-high (MSI-H), or with a high tumor mutational burden (TMB). Immunotherapy using checkpoint inhibitors is typically associated with adverse events (AEs) that are milder than those with chemotherapy. However, a significant percentage of patients develop short-term immune-related AEs (irAEs) which range from mild (~70%) to severe cases (~13%) that can lead to modifications of the checkpoint inhibitor therapy and in some cases, death. While some studies have investigated immune mechanisms behind the development of irAEs, much more research is needed to understand the mechanisms and to develop interventions that could attenuate severe irAEs, while maintaining the anti-tumor response intact. Moreover, studies to identify biomarkers that can predict the likelihood of a patient developing severe irAEs would be of great clinical importance. Here we discuss some of the clinical ramifications of irAEs, potential immune mechanisms behind their development and studies that have investigated potentially useful biomarkers of irAEs development.

Anti-CTLA-4 and anti-PD-1 immunotherapies repress tumor progression in preclinical breast and colon model with independent regulatory T cells response

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Anti-PD-1 and anti-CTLA-4 induced anti-tumor response in breast cancer mouse model.

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Anti-PD-1 and anti-CTLA-4 induced anti-tumor response in colon cancer mouse model.

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Anti-CTLA-4 reduced colon cancer–derived lung metastasis formation in a mouse model.

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We identified specific T cell response between anti-PD-1 and anti-CTLA-4.

The recent development of immunotherapy represents a significant breakthrough in cancer therapy. Several immunotherapies provide robust efficacy gains in a wide variety of cancers. However, in some patients the immune checkpoint blockade remains ineffective due to poor therapeutic response and tumor relapse. An improved understanding of the mechanisms underlying tumor-immune system interactions can improve clinical management of cancer. Here, we report preclinical data evaluating two murine antibodies corresponding to recent FDA-approved antibodies for human therapy, e.g. anti-CTLA-4 and anti-PD-1. We demonstrated in two mouse syngeneic grafting models of triple negative breast or colon cancer that the two antibodies displayed an efficient anticancer activity, which is enhanced by combination treatment in the breast cancer model. We also demonstrated that CTLA-4 targeting reduced metastasis formation in the colon cancer metastasis model. In addition, using cytometry-based multiplex analysis, we showed that anti-CTLA-4 and anti-PD-1 affected the tumor immune microenvironment differently and in particular the tumor immune infiltration. This work demonstrated anti-cancer effect of CTLA-4 or PD-1 blockade on mouse colon and triple negative breast and on tumor-infiltrating immune cell subpopulations that could improve our knowledge and benefit the breast and colon cancer tumor research community.

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.

Targeting HIF-1α abrogates PD-L1-mediated immune evasion in tumor microenvironment but promotes tolerance in normal tissues

Anti-CTLA-4 + anti-PD-1/PD-L1 combination is the most effective cancer immunotherapy but causes high incidence of immune-related adverse events (irAE). Here we report that targeting of HIF-1α suppressed PD-L1 expression on tumor cells and tumor-infiltrated myeloid cells, but unexpectedly induced PD-L1 in normal tissues by an IFNγ-dependent mechanism. Targeting the HIF-1α-PD-L1 axis in tumor cells reactivated tumor-infiltrating lymphocytes (TILs) and caused tumor rejection. The HIF-1α inhibitor echinomycin potentiated cancer immunotherapeutic effects of anti-CTLA-4 therapy with efficacy comparable to anti-CTLA-4+anti-PD-1 antibodies. However, while anti-PD-1 exacerbated irAE triggered by Ipilimumab, echinomycin protected mice against irAE by increasing PD-L1 levels in normal tissues. Our data suggest that targeting HIF-1α fortifies the immune tolerance function of the PD-1:PD-L1 checkpoint in normal tissues but abrogates its immune evasion function in the tumor microenvironment (TME) to achieve safer and more effective immunotherapy.

Emerging immunological strategies: recent advances and future directions

Immunotherapy plays a compelling role in cancer treatment and has already made remarkable progress. However, many patients receiving immune checkpoint inhibitors fail to achieve clinical benefits, and the response rates vary among tumor types. New approaches that promote anti-tumor immunity have recently been developed, such as small molecules, bispecific antibodies, chimeric antigen receptor T cell products, and cancer vaccines. Small molecule drugs include agonists and inhibitors that can reach the intracellular or extracellular targets of immune cells participating in innate or adaptive immune pathways. Bispecific antibodies, which bind two different antigens or one antigen with two different epitopes, are of great interest. Chimeric antigen receptor T cell products and cancer vaccines have also been investigated. This review explores the recent progress and challenges of different forms of immunotherapy agents and provides an insight into future immunotherapeutic strategies.

Mechanisms of immune checkpoint inhibitor-mediated liver injury

The immune checkpoints, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein-1/ligand-1 (PD-1/PD-L1) are vital contributors to immune regulation and tolerance. Recently immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy; however, they come with the cost of immune related adverse events involving multiple organs such as the liver. Due to its constant exposure to foreign antigens, the liver has evolved a high capacity for immune tolerance, therefore, blockade of the immune checkpoints can result in aberrant immune activation affecting the liver in up to 20% of patients depending on the agent(s) used and underlying factors. This type of hepatotoxicity is termed immune mediated liver injury from checkpoint inhibitors (ILICI) and is more common when CTLA4 and PD-1/PD-L1 are used in combination. The underlying mechanisms of this unique type of hepatotoxicity are not fully understood; however, the contribution of CD8+ cytotoxic T lymphocytes, various CD4+ T cells populations, cytokines, and the secondary activation of the innate immune system leading to liver injury have all been suggested. This review summarizes our current understanding of the underlying mechanisms of liver injury in immunotherapy using animal models of ILICI and available patient data from clinical studies.

Leveraging the Treg-intrinsic CTLA4-PKCη signaling pathway for cancer immunotherapy

Background

Our previous studies revealed a critical role of a novel CTLA4-protein kinase C-eta (PKCη) signaling axis in mediating the suppressive activity of regulatory T cells (Tregs) in antitumor immunity. These studies have employed adoptive transfer of germline PKCη-deficient (Prkch^−/−) Tregs into Prkch^+/+ mice prior to tumor implantation. Here, we extended these findings into a biologically and clinically more relevant context.

Methods

We have analyzed the role of PKCη in antitumor immunity and the tumor microenvironment (TME) in intact tumor-bearing mice with Treg-specific or CD8⁺ T cell-specific Prkch deletion, including in a therapeutic model of combinatorial treatment. In addition to measuring tumor growth, we analyzed the phenotype and functional attributes of tumor-infiltrating immune cells, particularly Tregs and dendritic cells (DCs).

Results

Using two models of mouse transplantable cancer and a genetically engineered autochthonous hepatocellular carcinoma (HCC) model, we found, first, that mice with Treg-specific Prkch deletion displayed a significantly reduced growth of B16–F10 melanoma and TRAMP-C1 adenocarcinoma tumors. Tumor growth reduction was associated with a less immunosuppressive TME, indicated by increased numbers and function of tumor-infiltrating CD8⁺ effector T cells and elevated expression of the costimulatory ligand CD86 on intratumoral DCs. In contrast, CD8⁺ T cell-specific Prkch deletion had no effect on tumor growth or the abundance and functionality of CD8⁺ effector T cells, consistent with findings that Prkch^−/− CD8⁺ T cells proliferated normally in response to in vitro polyclonal or specific antigen stimulation. Similar beneficial antitumor effects were found in mice with germline or Treg-specific Prkch deletion that were induced to develop an autochthonous HCC. Lastly, using a therapeutic model, we found that monotherapies consisting of Treg-specific Prkch deletion or vaccination with irradiated Fms-like tyrosine kinase 3 ligand (Flt3L)-expressing B16–F10 tumor cells post-tumor implantation significantly delayed tumor growth. This effect was more pronounced in mice receiving a combination of the two immunotherapies.

Conclusion

These findings demonstrate the potential utility of PKCη inhibition as a viable clinical approach to treat patients with cancer, especially when combined with adjuvant therapies.

Regional Delivery of Anti-PD-1 Agent for Colorectal Liver Metastases Improves Therapeutic Index and Anti-Tumor Activity

Metastatic liver tumors have presented challenges with the use of checkpoint inhibitors (CPIs), with only limited success. We hypothesize that regional delivery (RD) of CPIs can improve activity in the liver and minimize systemic exposure, thereby reducing immune-related adverse events (irAE). Using a murine model of colorectal cancer liver metastases (LM), we confirmed high levels of PD-L1 expression on the tumor cells and liver myeloid-derived suppressor cells (L-MDSC). In vivo, we detected improved LM response at 3 mg/kg on PTD7 via portal vein (PV) regional delivery as compared to 3 mg/kg via tail vein (TV) systemic delivery (p = 0.04). The minimal effective dose at PTD7 was 5 mg/kg (p = 0.01) via TV and 0.3 mg/kg (p = 0.02) via PV. We detected 6.7-fold lower circulating CPI antibody levels in the serum using the 0.3 mg/kg PV treatment compared to the 5 mg/kg TV cohort (p < 0.001) without increased liver toxicity. Additionally, 3 mg/kg PV treatment resulted in increased tumor cell apoptotic signaling compared to 5 mg/kg TV (p < 0.05). Therefore, RD of an anti-PD-1 CPI therapy for CRCLM may improve the therapeutic index by reducing the total dose required and limiting the systemic exposure. These advantages could expand CPI indications for liver tumors.

Engineered probiotics for local tumor delivery of checkpoint blockade nanobodies

Checkpoint inhibitors have revolutionized cancer therapy but only work in a subset of patients and can lead to a multitude of toxicities, suggesting the need for more targeted delivery systems. Because of their preferential colonization of tumors, microbes are a natural platform for the local delivery of cancer therapeutics. Here, we engineer a probiotic bacteria system for the controlled production and intratumoral release of nanobodies targeting programmed cell death-ligand 1 (PD-L1) and cytotoxic T lymphocyte-associated protein-4 (CTLA-4) using a stabilized lysing release mechanism. We used computational modeling coupled with experimental validation of lysis circuit dynamics to determine the optimal genetic circuit parameters for maximal therapeutic efficacy. A single injection of this engineered system demonstrated an enhanced therapeutic response compared to analogous clinically relevant antibodies, resulting in tumor regression in syngeneic mouse models. Supporting the potentiation of a systemic immune response, we observed a relative increase in activated T cells, an abscopal effect, and corresponding increases in systemic T cell memory populations in mice treated with probiotically delivered checkpoint inhibitors. Last, we leveraged the modularity of our platform to achieve enhanced therapeutic efficacy in a poorly immunogenic syngeneic mouse model through effective combinations with a probiotically produced cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF). Together, these results demonstrate that our engineered probiotic system bridges synthetic biology and immunology to improve upon checkpoint blockade delivery.

Single-Cell Transcriptome Analysis Reveals the M2 Macrophages and Exhausted T Cells and Intratumoral Heterogeneity in Triple-Negative Breast Cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a highly heterogeneous and invasive malignancy that is characterized by high recurrence and mortality rates as well as extremely poor prognosis.

OBJECTIVE

This study aimed to analyze T cells and macrophages in the tumor microenvironment with the aim of identifying targets with therapeutic potential.

METHOD

Single-cell sequencing data of TNBC patients from the GSE118389 dataset were analyzed to examine the immune environment and intratumoral heterogeneity of TNBC patients.

RESULT

Polarized alternatively activated macrophages (M2) and exhausted CD8+ T cells were identified in TNBC patients. Immunosuppressive checkpoint analysis revealed that levels of lymphocyte-activation gene 3 (LAG3) and T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) of exhausted T cells were significantly higher than levels of programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). This indicates that these markers are potential immunotherapy targets. Furthermore, analysis of significantly altered immune cell markers showed that several markers are associated with the prognosis of TNBC.

CONCLUSION

Overall, these findings demonstrate inter-tissue heterogeneity of TNBC and provide novel therapeutic targets for the treatment of TNBC.

Cytotoxic T lymphocyte-associated protein 4 antibody aggrandizes antitumor immune response of oncolytic virus M1 via targeting regulatory T cells

Oncolytic virotherapies are perceived as remarkable immunotherapies coming into view and represent highly promising cancer treatments, yet to figure out its specific immune responses and underlying barriers remains critical. Albeit recent studies have demonstrated that oncolytic viruses (OVs) could fine tune tumor microenvironment (TME) to elicit tumor suppression mainly due to effective T-cell responses, the interaction between suppressive T cells and OVs is barely undetermined. Herein, we found that regulatory T cells (Treg cells) were increased in the TME following systemic administration of oncolytic virus M1 along with the higher expression of relative cytokines and chemokines in both mouse RM-1 prostatic carcinoma model and mouse B16F10 melanoma model. Besides, Treg cells expressed high levels of CD25 post-M1 treatment, and its suppressive effect on CD8⁺ T cells was also elevated. Depletion of Treg cells in M1-treated groups significantly reinforced antitumor effect of M1. Specific targeting of Treg cells using cytotoxic T lymphocyte-associated protein 4 (CTLA-4) antibody (Ab) in combination with M1 treatment elicited a more profound tumor suppression and longer overall survival time than M1 alone in both tumor models. Moreover, CTLA-4 Ab further aggrandized antitumor immune response elicited by M1, including increased infiltration of CD45⁺ immune cells and CD8⁺ or CD4⁺ T lymphocytes, decreased ratio of Treg cells to CD4⁺ T lymphocytes, the intensified lymphocytotoxicity and elevated secretion of cytotoxic cytokines like interferon-γ, granzyme B and perforin. Therefore, our findings constituted a suggestive evidence that targeting Treg cells in M1-based oncolytic virotherapy may achieve a highly response in clinical cancer research.

Functional Immunostimulating DNA Materials: The Rising Stars for Cancer Immunotherapy

Cancer immunotherapy has risen as a promising method in clinical practice for cancer treatment and DNA-based immune intervention materials, along with DNA nanotechnology, have obtained increasing importance in this field. In this review, various immunostimulating DNA materials are introduced and the mechanisms via which they exerted an immune effect are explained. Then, representative examples in which DNA is used as the leading component for anticancer applications through immune stimulation are provided and their efficacy is evaluated. Finally, the challenges for those materials in clinical applications are discussed and suggestions for possible further research directions are also put forward.

Humanized Mouse Models for the Advancement of Innate Lymphoid Cell-Based Cancer Immunotherapies

Innate lymphoid cells (ILCs) are a branch of the immune system that consists of diverse circulating and tissue-resident cells, which carry out functions including homeostasis and antitumor immunity. The development and behavior of human natural killer (NK) cells and other ILCs in the context of cancer is still incompletely understood. Since NK cells and Group 1 and 2 ILCs are known to be important for mediating antitumor immune responses, a clearer understanding of these processes is critical for improving cancer treatments and understanding tumor immunology as a whole. Unfortunately, there are some major differences in ILC differentiation and effector function pathways between humans and mice. To this end, mice bearing patient-derived xenografts or human cell line-derived tumors alongside human genes or human immune cells represent an excellent tool for studying these pathways in vivo. Recent advancements in humanized mice enable unparalleled insights into complex tumor-ILC interactions. In this review, we discuss ILC behavior in the context of cancer, the humanized mouse models that are most commonly employed in cancer research and their optimization for studying ILCs, current approaches to manipulating human ILCs for antitumor activity, and the relative utility of various mouse models for the development and assessment of these ILC-related immunotherapies.

Physiological and Immunological Causes of the Susceptibility of Chronic Inflammatory Patients to COVID-19 Infection: Focus on Diabetes

The coronavirus disease 2019 (COVID-19) pandemic has recently emerged, which was then spread rapidly in more than 190 countries worldwide so far. According to the World Health Organization, 3,232,062 global cases of COVID-19 were confirmed on April 30th with a mortality rate of 3.4%. Notably, the symptoms are almost similar to those of flu such as fever, cough, and fatigue. Unfortunately, the global rates of morbidity and mortality caused by this disease are more and still increasing on a daily basis. The rates for patients suffering from inflammatory diseases like diabetes, is even further, due to their susceptibility to the pathogenesis of COVID-19. In this review, we attempted to focus on diabetes to clarify the physiological and immunological characteristics of diabetics before and after the infection with COVID-19. We hope these conceptions could provide a better understanding of the mechanisms involved in COVID-19 susceptibility and increase the awareness of risk to motivate behavior changes in vulnerable people for enhancing the prevention. Up to now, the important role of immune responses, especially the innate ones, in the development of the worst signs in COVID-19 infection have been confirmed. Therefore, to better control patients with COVID-19, it is recommended to consider a history of chronic inflammatory diseases as well as the way of controlling immune response in these patients.

A novel mouse model for checkpoint inhibitor-induced adverse events

Immune checkpoint inhibitors have demonstrated significant efficacy in the treatment of a variety of cancers, however their therapeutic potential is limited by abstruse immune related adverse events. Currently, no robust animal model exists of checkpoint inhibitor-induced adverse events. Establishing such a model will improve our mechanistic understanding of this process, which in turn will inform design of improved therapies. We developed a mouse model to determine inflammatory toxicities in response to dual checkpoint blockade in the presence of syngeneic tumors. Mice from susceptible genetic backgrounds received intraperitoneal injections of anti-mouse PD-1 and CTLA-4 antibodies. The mice were monitored for weight loss and histologic evidence of inflammation. Blood was collected for basic metabolic panels and titers of anti-nuclear antibodies. In parallel, mice were also treated with prednisolone, which is commonly used to treat immune related adverse events among cancer patients. Among all the genetic backgrounds, B6/lpr mice treated with anti-CTLA-4 and anti-PD-1 antibodies developed more substantial hepatitis, pancreatitis, colitis, and pneumonitis characterized by organ infiltration of immune cells. Mice that developed tissue infiltration demonstrated high serum levels of glucose and high titers of anti-nuclear antibodies. Finally, while administration of prednisolone prevented the development of the inflammatory adverse events, it also abrogated the protective anti-tumor effect of the checkout inhibitors. Genetic background and treatment modalities jointly modified the inflammatory adverse events in tumor bearing mice, suggesting a complex mechanism for checkpoint inhibitor-related inflammation. Future studies will assess additional genetic susceptibility factors and will examine possible contributions from the administration of other anti-inflammatory drugs.

Immune Checkpoint Inhibitors: Cardiotoxicity in Pre-clinical Models and Clinical Studies

Since the approval of the first immune checkpoint inhibitor (ICI) 9 years ago, ICI-therapy have revolutionized cancer treatment. Lately, antibodies blocking the interaction of programmed cell death protein (PD-1) and ligand (PD-L1) are gaining momentum as a cancer treatment, with multiple agents and cancer types being recently approved for treatment by the US Food and Drug Administration (FDA). Unfortunately, immunotherapy often leads to a wide range of immune related adverse events (IRAEs), including several severe cardiac effects and most notably myocarditis. While increased attention has been drawn to these side effects, including publication of multiple clinical observational data, the underlying mechanisms are unknown. In the event of IRAEs, the most widely utilized clinical solution is administration of high dose corticosteroids and in severe cases, discontinuation of these ICIs. This is detrimental as these therapies are often the last line of treatment options for many types of advanced cancer. In this review, we have systematically described the pathophysiology of the PD-1/PD-L1 axis (including a historical perspective) and cardiac effects in pre-clinical models, clinical trials, autoimmune mechanisms, and immunotherapy in combination with other cancer treatments. We have also reviewed the current challenges in the diagnosis of cardiac events and future directions in the field. In conclusion, this review will delve into this expanding field of cancer immunotherapy and the emerging adverse effects that should be quickly detected and prevented.

Efficacy and immune-related adverse event associations in avelumab-treated patients

BACKGROUND

Adverse events (AEs) of special interest that arise during treatment with immune checkpoint inhibitors, including immune-related AEs (irAEs), have been reported to be associated with improved clinical outcomes. We analyzed patients treated with avelumab from the JAVELIN Solid Tumor and Merkel 200 trials, examining the association between AEs and efficacy while adjusting for confounding factors such as treatment duration and event order.

METHODS

We analyzed efficacy and safety data from 1783 patients treated with the programmed death ligand 1 inhibitor avelumab who were enrolled in expansion cohorts of the JAVELIN Solid Tumor and Merkel 200 trials. To analyze the association between irAEs and efficacy with regard to survival, we used a time-dependent Cox model with time-varying indicators for irAEs, as well as multistate models that accounted for competing risks and time inhomogeneity.

RESULTS

295 patients (16.5%) experienced irAEs and 454 patients (25.5%) experienced infusion-related reactions. There was a reduced risk of death in patients who experienced irAEs compared with those who did not (HR 0.71, 95% CI 0.59 to 0.85) using the time-dependent Cox model. The multistate model did not suggest that the occurrence of irAEs could predict response; however, it predicted a higher chance of irAEs occurring after a response. No association was observed between response and infusion-related reactions.

CONCLUSIONS

Patients who experience irAEs showed improved survival. Although irAEs are not predictors for response to immune checkpoint inhibitors, increased vigilance for irAEs is needed after treatment with avelumab.

TRIAL REGISTRATION NUMBERS

NCT01772004 and NCT02155647.

Uncoupling Therapeutic Efficacy from Immune-Related Adverse Events in Immune Checkpoint Blockade

Immunotherapy with monoclonal antibodies targeting immune checkpoint molecules, including programmed death-1 (PD-1), PD ligand-1 (PD-L1), and cytotoxic T-lymphocyte-associated antigen (CTLA)-4, has become prominent in the treatment of many types of cancer. However, a significant number of patients treated with immune checkpoint inhibitors (ICIs) develop immune-related adverse events (irAEs). irAEs can affect any organ system, and although most are clinically manageable, irAEs can result in mortality or long-term morbidity. Factors that can predict irAEs remain elusive. Understanding the etiology of ICI-induced irAEs and ways to limit these adverse events are needed. In this review, we provide basic science and clinical insights on the mechanisms responsible for ICI efficacy and ICI-induced irAEs. We further provide insights into approaches that may uncouple irAEs from the ability of ICIs to kill tumor cells.