CTLA-4 blockade increases IFNgamma-producing CD4+ICOShi cells to shift the ratio of effector to regulatory T cells in cancer patients

Gut microbiota in hepatocellular carcinoma immunotherapy: immune microenvironment remodeling and gut microbiota modification

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality, with limited treatment options at advanced stages. The gut microbiota, a diverse community of microorganisms residing in the gastrointestinal tract, plays a pivotal role in regulating immune responses through the gut-liver axis. Emerging evidence underscores its impact on HCC progression and the efficacy of immunotherapy. This review explores the intricate interactions between gut microbiota and the immune system in HCC, with a focus on key immune cells and pathways involved in tumor immunity. Additionally, it highlights strategies for modulating the gut microbiota - such as fecal microbiota transplantation, dietary interventions, and probiotics - as potential approaches to enhancing immunotherapy outcomes. A deeper understanding of these mechanisms could pave the way for novel therapeutic strategies aimed at improving patient prognosis.

A SITC vision: adapting clinical trials to accelerate drug development in cancer immunotherapy

Clinical trials of cancer immunotherapy (IO) were historically based on a drug development paradigm built for chemotherapies. The remarkable clinical activity of programmed cell death protein 1/programmed death ligand 1 blockade, chimeric antigen receptor-T cells, and T cell engagers yielded new insights into how the mechanistic underpinnings of IO are reflected in the clinic. These insights and the sheer number of novel immunotherapies currently in the pipeline have made it clear that our strategies and tools for IO drug development must adapt. Recent innovations like engineered T cells and tumor-infiltrating lymphocytes demonstrate that immune-based treatments may rely on real-time manufacturing programs rather than off-the-shelf drugs. We now recognize adoptively transferred cells as living drugs. Progression criteria have been redefined due to the unique response patterns of IO. Harnessing the power of both biomarkers and the neoadjuvant setting earlier in drug development is of broad interest. The US Food and Drug Association is increasingly impacting the design of trials with respect to dose optimization and clinical endpoints. The use of novel endpoints such as pathologic complete/major response, treatment-free survival, and minimal residual disease is becoming more common. There is growing acceptance of using patient-reported outcomes as trial endpoints to better measure the true clinical benefit and impact of novel IO agents on quality of life. New opportunities created by modern data science and artificial intelligence to inform and accelerate drug development continue to emerge. The importance of streamlining the clinical research ecosystem and enhancing clinical trial access to facilitate the enrollment of diverse patient populations is broadly recognized. Patient advocacy is critical both to drive the science of IO, and to promote patient satisfaction. To capitalize on these opportunities, the Society for Immunotherapy of Cancer (SITC) has established a goal of at least 100 new, unique IO approvals over the next 10 years. Accordingly, SITC has developed initiatives designed to integrate the viewpoints of diverse stakeholders and galvanize the field in further adapting clinical trials to the unique features of IO, moving us closer to our ultimate goal of using IO to cure and prevent cancer.

Neoadjuvant immune checkpoint therapy: Enabling insights into fundamental human immunology and clinical benefit

While immune checkpoint therapy (ICT) has revolutionized cancer treatment, most patients with advanced disease fail to achieve durable benefit. To address this challenge, it is essential to integrate mechanistic research with clinical studies to: (1) understand response mechanisms, (2) identify patient-specific resistance pathways, (3) develop biomarkers for patient selection, and (4) design novel therapies to overcome resistance. We propose that incorporating "direct-in-patient" studies into clinical trials is crucial for bridging the gap between fundamental science and clinical oncology. In this review, we first highlight recent clinical success of ICT in the neoadjuvant setting, where treatment is given in earlier disease stages to improve outcomes. We then explore how neoadjuvant clinical trials could be utilized to drive mechanistic laboratory-based investigations. Finally, we discuss novel scientific concepts that will potentially aid in overcoming resistance to ICT, which will require future clinical trials to understand their impact on human immune responses.

ICOS-expressing CAR-T cells mediate durable eradication of triple-negative breast cancer and metastasis

Triple-negative breast cancer (TNBC) remains one of the most aggressive and therapeutically challenging breast cancer subtypes. In their recent study, Cao et al introduced a B7H3-specific chimeric antigen receptor (CAR)-T cell with constitutive inducible co-stimulator (ICOS) expression (ICOS-B7H3-CAR-T), which demonstrated eradication of TNBC, including metastases, in preclinical models. These CAR-T cells exploit the expression of ICOS ligand on TNBC cells, enhancing antitumor cytotoxicity through ICOS signaling. Compared with conventional B7H3-CAR-T cells, the ICOS-B7H3-CAR-T cells exhibited superior antitumor efficacy, increased cytokine secretion, and prolonged survival in xenograft murine models. This study highlights ICOS as a promising co-stimulatory molecule for improving CAR-T therapy against solid tumors and underscores the critical role of ICOS signaling in enhancing therapeutic outcomes. Here, we discuss the implications of these findings for TNBC treatment, the importance of understanding and exploiting ICOS biology in immunotherapies, and future directions for optimizing ICOS CAR-T cell therapies in solid tumor immunotherapy.

Immune checkpoint protein PD-L1 promotes transcription of angiogenic and oncogenic proteins IL-8, Bcl3, and STAT1 in ovarian cancer cells

Immunotherapies blocking cell surface signaling of the immune checkpoint PD-L1 have shown great promise in several cancers, but the results have been disappointing in ovarian cancer (OC). One of the main underlying mechanisms likely consists of the cell-intrinsic intracellular functions of PD-L1, which are incompletely understood. The expression of PD-L1 in OC cells is induced by interferon-γ (IFNγ), a pleiotropic cytokine produced in response to chemotherapy or immune checkpoint blockade. We have recently shown that IFNγ induces expression of the proto-oncogene Bcl3, the proangiogenic chemokine interleukin-8 (IL-8)-CXCL8, and the transcription factor STAT1, resulting in increased OC cell proliferation and migration. Here, we report that IFNγ-induced expression of PD-L1 results in PD-L1 recruitment to IL-8, Bcl3, and STAT1 promoters. The occupancy of PD-L1 at IL-8, Bcl3, and STAT1 promoters is associated with increased histone acetylation and RNA polymerase II recruitment to these promoters. Suppression of IFNγ-induced PD-L1 decreases the expression of IL-8, Bcl3, and PD-L1 and increases apoptosis in OC cells. Together, these findings demonstrate that PD-L1 promotes transcription of IL-8, Bcl3, and STAT1, thus providing a novel function of PD-L1 in cancer cells, and suggesting that the increased IL-8, Bcl3, and STAT1 expression mediated by PD-L1 might contribute to the limited effectiveness of cancer immunotherapies targeting the surface expression of PD-L1 in OC.

Anti-CTLA-4 generates greater memory response than anti-PD-1 via TCF-1

The effects of T cell differentiation arising from immune checkpoint inhibition targeting cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1) on the immunological memory response remain unclear. Our investigation into the effects of anti-CTLA-4 and anti-PD-1 on memory T cell formation in mice reveals that memory T cells generated by anti-CTLA-4 exhibit greater expansion, cytokine production, and antitumor activity than those from anti-PD-1. Notably, anti-CTLA-4 preserves more T cell factor-1 (TCF-1)+ T cells during priming, while anti-PD-1 leads to more thymocyte selection-associated high mobility group box (TOX)+ T cells. Experiments using conditional Tcf7- or Tox-knockout mice highlight that TCF-1 is essential for the memory response generated by anti-CTLA-4, whereas TOX deletion alone in T cells has no effect on the response to anti-PD-1. Deepening our understanding of how checkpoint inhibition affects memory response is crucial for advancing our understanding of the enduring impacts of these immunotherapies on the immune system.

Early changes of peripheral circulating immune subsets induced by PD-1 inhibitors in patients with advanced malignant melanoma and non-small cell lung cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs), including those targeting PD-1, are currently used in a wide range of tumors, but only 20-40% of patients achieve clinical benefit. The objective of our study was to find predictive peripheral blood-based biomarkers for ICI treatment.

METHODS

In 41 patients with advanced malignant melanoma (MM) and NSCLC treated with PD-1 inhibitors, we analyzed peripheral blood-based immune subsets by flow cytometry before treatment initialization and the second therapy dose. Specifically, we assessed basic blood differential count, overall T cells and their subgroups, B cells, and myeloid-derived suppressor cells (MDSC). In detail, CD4 + and CD8 + T cells were assessed according to their subtypes, such as central memory T cells (TCM), effector memory T cells (TEM), and naïve T cells (TN). Furthermore, we also evaluated the predictive value of CD28 and ICOS/CD278 co-expression on T cells.

RESULTS

Patients who achieved disease control on ICIs had a significantly lower baseline proportion of CD4 + TEM (p = 0.013) and tended to have a higher baseline proportion of CD4 + TCM (p = 0.059). ICI therapy-induced increase in Treg count (p = 0.012) and the proportion of CD4 + TN (p = 0.008) and CD28 + ICOS- T cells (p = 0.012) was associated with disease control. Patients with a high baseline proportion of CD4 + TCM and a low baseline proportion of CD4 + TEM showed significantly longer PFS (p = 0.011, HR 2.6 and p ˂ 0.001, HR 0.23, respectively) and longer OS (p = 0.002, HR 3.75 and p ˂ 0.001, HR 0.15, respectively). Before the second dose, the high proportion of CD28 + ICOS- T cells after ICI therapy initiation was significantly associated with prolonged PFS (p = 0.017, HR 2.51) and OS (p = 0.030, HR 2.69). Also, a high Treg count after 2 weeks of ICI treatment was associated with significantly prolonged PFS (p = 0.016, HR 2.33).

CONCLUSION

In summary, our findings suggest that CD4 + TEM and TCM baselines and an early increase in the Treg count induced by PD-1 inhibitors and the proportion of CD28 + ICOS- T cells may be useful in predicting the response in NSCLC and MM patients.

A multi-task deep learning model based on comprehensive feature integration and self-attention mechanism for predicting response to anti-PD1/PD-L1

BACKGROUND

Immune checkpoint inhibitor (ICI) has been widely used in the treatment of advanced cancers, but predicting their efficacy remains challenging. Traditional biomarkers are numerous but exhibit heterogeneity within populations. For comprehensively utilizing the ICI-related biomarkers, we aim to conduct multidimensional feature selection and deep learning model construction.

METHODS

We used statistical and machine learning methods to map features of different levels to next-generation sequencing gene expression. We integrated genes from different sources into the feature input of a deep learning model, by means of self-attention mechanism.

RESULTS

We performed feature selection at the single-cell sequencing level, PD-L1 (CD274) analysis level, tumor mutational burden (TMB)/mismatch repair (MMR) level, and somatic copy number alteration (SCNA) level, obtaining 96 feature genes. Based on the pan-cancer dataset, we trained a multi-task deep learning model. We tested the model in the bladder urothelial carcinoma testing set 1 (AUC = 0.62, n = 298), bladder urothelial carcinoma testing set 2 (AUC = 0.66, n = 89), non-small cell lung cancer testing set (AUC = 0.85, n = 27), and skin cutaneous melanoma testing set (AUC = 0.71, n = 27).

CONCLUSION

Our study demonstrates the potential of the deep learning model for integrating multidimensional features in predicting the outcome of ICI. Our study also provides a potential methodological case for medical scenarios requiring the integration of multiple levels of features.

Next-generation combination approaches for immune checkpoint therapy

Immune checkpoint therapy has revolutionized cancer treatment, leading to dramatic clinical outcomes for a subset of patients. However, many patients do not experience durable responses following immune checkpoint therapy owing to multiple resistance mechanisms, highlighting the need for effective combination strategies that target these resistance pathways and improve clinical responses. The development of combination strategies based on an understanding of the complex biology that regulates human antitumor immune responses has been a major challenge. In this Review, we describe the current landscape of combination therapies. We also discuss how the development of effective combination strategies will require the integration of small, tissue-rich clinical trials, to determine how therapy-driven perturbation of the human immune system affects downstream biological responses and eventual clinical outcomes, reverse translation of clinical observations to immunocompetent preclinical models, to interrogate specific biological pathways and their impact on antitumor immune responses, and novel computational methods and machine learning, to integrate multiple datasets across clinical and preclinical studies for the identification of the most relevant pathways that need to be targeted for successful combination strategies.

ICOS-expressing CAR-T cells mediate durable eradication of triple-negative breast cancer and metastasis

BACKGROUND

The failure of conventional therapies and the propensity for recurrence and metastasis make triple-negative breast cancer (TNBC) a formidable challenge with grim prognoses and diminished survival rates. Immunotherapy, including immune checkpoint blockade and chimeric antigen receptor (CAR)-T cell therapy, presents innovative and potentially more effective strategies for addressing TNBC. Within this context, the inducible costimulator (ICOS), a member of the CTLA4/CD28 family, plays a crucial role in regulating immune responses and T-cell differentiation by binding to its ligand ICOSL. However, the impact of the ICOS/ICOSL axis on cancer varies.

METHODS

In this study, immunohistochemistry was conducted to examine the expression level of ICOSL in TNBC tumor tissues. We developed ICOS-enhanced B7H3-CAR-T cells (ICOS-B7H3-CAR) using the third-generation CAR-T cell technology, which featured magnified ICOS expression and targeted the B7H3 antigen. Xenograft and metastasis models of TNBC were conducted to examine the cytotoxicity and durability of CAR-T cells in tumors. Overexpression and CRISPR/Cas9-mediated knockout (KO) techniques were employed to regulate the expression of ICOSL on TNBC cell lines.

RESULTS

Notably, we observed elevated ICOSL expression in TNBC tumor tissues, which correlated with poor survival prognosis in patients with TNBC. Compared with conventional B7H3-CAR-T cells, ICOS-B7H3-CAR-T cells significantly inhibited the tumor growth of TNBC cells both in vitro and in vivo, accompanied by increased secretion of cytokines such as interferon gamma and tumor necrosis factor alpha. Furthermore, the in vivo experiments illustrated that ICOS-B7H3-CAR-T cells exhibited prolonged antitumor activity and could effectively eradicate metastases in a TNBC metastasis model, consequently extending survival. Importantly, manipulating the expression of ICOSL on TNBC cells through overexpression or KO significantly influenced the function of ICOS-B7H3-CAR-T cells. This suggests that the level of ICOSL expression on TNBC cells is critical for enhancing the potent antitumor effects of ICOS-B7H3-CAR-T cells.

CONCLUSION

Overall, our study highlights the potential clinical application of ICOS as a promising strategy for combating TNBC recurrence and metastasis.

Fc Effector Function of Immune Checkpoint Blocking Antibodies in Oncology

Antagonistic monoclonal antibodies (mAbs) targeting inhibitory immune checkpoints have revolutionized the field of oncology. CTLA-4, PD-1, and LAG3 are three co-inhibitory receptors, which can be expressed by subsets of T cells and which play a role in the regulation of adaptive immune responses. Blocking these immune checkpoints receptors (or their ligands) with antagonistic antibodies can lead to tumor regressions and lasting remissions in some patients with cancer. Two anti-CTLA4, six anti-PD1, three anti-PD-L1, and one anti-LAG3 antibodies are currently approved by the FDA and EMA. Their mechanism of action, safety, and efficacy are linked to their affinity with Fc gamma receptors (FcγR) (so called "effector functions"). The anti-CTLA-4 antibodies ipilimumab (IgG1) and tremilimumab (IgG2a), and the anti-PD-L1 avelumab (IgG1) have isotypes with high affinity for activating FcγR and thereby can induce ADCC/ADCP. The effector function is required for the in vivo efficacy of anti-CTLA4 antibodies. For anti-PD(L)1 antibodies, where a pure antagonistic function ("checkpoint blockade") is sufficient, some mAbs are IgG1 but have been mutated in their Fc sequence (e.g., durvalumab and atezolizumab) or are IgG4 (e.g., nivolumab and pembrolizumab) to have low affinity for FcγR. Here, we review the impact of FcγR effector function on immune checkpoint blockers safety and efficacy in oncology.

Unraveling Th subsets: insights into their role in immune checkpoint inhibitor therapy

T helper (Th) cell subsets play pivotal roles in regulating immune responses within the tumor microenvironment, influencing both tumor progression and anti-tumor immunity. Among these subsets, Th1 cells promote cytotoxic responses through the production of IFN-γ, while Th2 cells and regulatory T cells (Tregs) exert immunosuppressive effects that support tumor growth. Th9 and Th17 cells have context-dependent roles, contributing to both pro-inflammatory and regulatory processes in tumor immunity. Tumor antigen-specific T cells within the tumor microenvironment often exhibit a dysfunctional phenotype due to increased expression of inhibitory receptors such as CTLA-4 and PD-1, leading to reduced antitumor activity. Monoclonal antibodies that block these inhibitory signals-collectively known as immune checkpoint inhibitors (ICIs)-can reactivate these T cells, enhancing their ability to target and destroy cancer cells. Recent advancements have highlighted the critical role of T helper subsets in modulating responses to ICIs, with their interactions remaining a focus of ongoing research. Both positive and negative effects of ICIs have been reported in relation to Th cell subsets, with some effects depending on the type of tumor microenvironment. This review summarizes the crucial roles of different T helper cell subsets in tumor immunity and their complex relationship with immune checkpoint inhibitor therapy.

Tumor-Localized Interleukin-2 and Interleukin-12 Combine with Radiation Therapy to Safely Potentiate Regression of Advanced Malignant Melanoma in Pet Dogs

PURPOSE

Cytokines IL2 and IL12 exhibit potent anticancer activity but suffer a narrow therapeutic window due to off-tumor immune cell activation. Engineering cytokines with the ability to bind and associate with tumor collagen after intratumoral injection potentiated response without toxicity in mice and was previously safe in pet dogs with sarcoma. Here, we sought to test the efficacy of this approach in dogs with advanced melanoma.

PATIENTS AND METHODS

This study examined 15 client-owned dogs with histologically or cytologically confirmed malignant melanoma that received a single 9-Gy fraction of radiotherapy, followed by six cycles of combined collagen-anchored IL2 and IL12 therapy every 2 weeks. Cytokine dosing followed a 3 + 3 dose escalation design, with the initial cytokine dose chosen from prior evaluation in canine sarcomas. No exclusion criteria for tumor stage or metastatic burden, age, weight, or neuter status were applied for this trial.

RESULTS

Median survival regardless of the tumor stage or dose level was 256 days, and 10/13 (76.9%) dogs that completed treatment had CT-measured tumor regression at the treated lesion. In dogs with metastatic disease, 8/13 (61.5%) had partial responses across their combined lesions, which is evidence of locoregional response. Profiling by NanoString of treatment-resistant dogs revealed that B2m loss was predictive of poor response to this therapy.

CONCLUSIONS

Collectively, these results confirm the ability of locally administered tumor-anchored cytokines to potentiate responses at regional disease sites when combined with radiation. This evidence supports the clinical translation of this approach and highlights the utility of comparative investigation in canine cancers.

Combination anti-PD-1 and anti-CTLA-4 therapy generates waves of clonal responses that include progenitor-exhausted CD8+ T cells

Combination checkpoint blockade with anti-PD-1 and anti-CTLA-4 antibodies has shown promising efficacy in melanoma. However, the underlying mechanism in humans remains unclear. Here, we perform paired single-cell RNA and T cell receptor (TCR) sequencing across time in 36 patients with stage IV melanoma treated with anti-PD-1, anti-CTLA-4, or combination therapy. We develop the algorithm Cyclone to track temporal clonal dynamics and underlying cell states. Checkpoint blockade induces waves of clonal T cell responses that peak at distinct time points. Combination therapy results in greater magnitude of clonal responses at 6 and 9 weeks compared to single-agent therapies, including melanoma-specific CD8+ T cells and exhausted CD8+ T cell (TEX) clones. Focused analyses of TEX identify that anti-CTLA-4 induces robust expansion and proliferation of progenitor TEX, which synergizes with anti-PD-1 to reinvigorate TEX during combination therapy. These next generation immune profiling approaches can guide the selection of drugs, schedule, and dosing for novel combination strategies.

Toxicity in the era of immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) reinvigorate anti-tumor immune responses by disrupting co-inhibitory immune checkpoint molecules such as programmed cell death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4). Although ICIs have had unprecedented success and have become the standard of care for many cancers, they are often accompanied by off-target inflammation that can occur in any organ system. These immune related adverse events (irAEs) often require steroid use and/or cessation of ICI therapy, which can both lead to cancer progression. Although irAEs are common, the detailed molecular and immune mechanisms underlying their development are still elusive. To further our understanding of irAEs and develop effective treatment options, there is pressing need for preclinical models recapitulating the clinical settings. In this review, we describe current preclinical models and immune implications of ICI-induced skin toxicities, colitis, neurological and endocrine toxicities, pneumonitis, arthritis, and myocarditis along with their management.

Anti-CTLA-4 treatment suppresses hepatocellular carcinoma growth through Th1-mediated cell cycle arrest and apoptosis

Inhibiting the cytotoxic T-lymphocyte-associated protein-4 (CTLA-4)-mediated immune checkpoint system using an anti-CTLA-4 antibody (Ab) can suppress the growth of various cancers, but the detailed mechanisms are unclear. In this study, we established a monoclonal hepatocellular carcinoma cell line (Hepa1-6 #12) and analyzed the mechanisms associated with anti-CTLA-4 Ab treatment. Depletion of CD4+ T cells, but not CD8+ T cells, prevented anti-CTLA-4 Ab-mediated anti-tumor effects, suggesting dependence on CD4+ T cells. Anti-CTLA-4 Ab treatment resulted in recruitment of interferon-gamma (IFN-g)-producing CD4+ T cells, called T-helper 1 (Th1), into tumors, and neutralization of IFN-g abrogated the anti-tumor effects. Moreover, tumor growth suppression did not require major histocompatibility complex (MHC)-I or MHC-II expression on cancer cells. In vitro studies showed that IFN-g can induce cell cycle arrest and apoptosis in tumor cells. Taken together, these data demonstrate that anti-CTLA-4 Ab can exert its anti-tumor effects through Th1-mediated cell cycle arrest and apoptosis.

Phase I studies of davoceticept (ALPN-202), a PD-L1-dependent CD28 co-stimulator and dual PD-L1/CTLA-4 inhibitor, as monotherapy and in combination with pembrolizumab in advanced solid tumors (NEON-1 and NEON-2)

BACKGROUND

Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain designed to mediate programmed death-ligand 1 (PD-L1)-dependent CD28 co-stimulation while inhibiting the PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) checkpoints. The safety and efficacy of davoceticept monotherapy and davoceticept and pembrolizumab combination therapy in adult patients with advanced solid tumors were explored in NEON-1 and NEON-2, respectively.

METHODS

In NEON-1 (n=58), davoceticept 0.001-10 mg/kg was administered intravenous either once weekly (Q1W) or once every 3 weeks (Q3W). In NEON-2 (n=29), davoceticept was administered intravenously at 2 dose levels (0.1 or 0.3 mg/kg) Q1W or Q3W with pembrolizumab (400 mg once every 6 weeks). In both studies, primary endpoints included incidence of dose-limiting toxicities (DLT); type, incidence, and severity of adverse events (AEs) and laboratory abnormalities; and seriousness of AEs. Secondary endpoints included antitumor efficacy assessed using RECIST v1.1, pharmacokinetics, anti-drug antibodies, and pharmacodynamic biomarkers.

RESULTS

The incidence of treatment-related AEs (TRAEs) and immune-related adverse events (irAEs) was 67% (39/58) and 36% (21/58) with davoceticept monotherapy, and 62% (18/29) and 31% (9/29) with davoceticept and pembrolizumab combination, respectively. The incidence of ≥grade (Gr)3 TRAEs and ≥Gr3 irAEs was 12% (7/58) and 5% (3/58) with davoceticept monotherapy, and 24% (7/29) and 10% (3/29) with davoceticept and pembrolizumab combination, respectively. One DLT of Gr3 immune-related gastritis occurred during davoceticept monotherapy 3 mg/kg Q3W. During davoceticept combination with pembrolizumab, two Gr5 cardiac DLTs occurred; one instance each of cardiogenic shock (0.3 mg/kg Q3W, choroidal melanoma metastatic to the liver) and immune-mediated myocarditis (0.1 mg/kg Q3W, microsatellite stable metastatic colorectal adenocarcinoma), prompting early termination of both studies. Across both studies, five patients with renal cell carcinoma (RCC) exhibited evidence of clinical benefit (two partial response, three stable disease).

CONCLUSIONS

Davoceticept was generally well tolerated as monotherapy at intravenous doses up to 10 mg/kg. Evidence of clinical activity was observed with davoceticept monotherapy and davoceticept in combination with pembrolizumab, notably in RCC. However, two fatal cardiac events occurred with the combination of low-dose davoceticept and pembrolizumab. Future clinical investigation with davoceticept should not consider combination with programmed death-1-inhibitor anticancer mechanisms, until its safety profile is more fully elucidated.

TRIAL REGISTRATION NUMBER

NEON-1 (NCT04186637) and NEON-2 (NCT04920383).

In-depth cross-validation of human and mouse CD4-specific minibodies for noninvasive PET imaging of CD4+ cells and response prediction to cancer immunotherapy

Increasing evidence emphasizes the pivotal role of CD4+ T cells in orchestrating cancer immunity. Noninvasive in vivo imaging of the temporal dynamics of CD4+ T cells and their distribution patterns might provide novel insights into their effector and regulator cell functions during cancer immunotherapy (CIT). Methods: We conducted a comparative analysis of 89Zr-labeled anti-mouse (m) and anti-human (h) CD4-targeting minibodies (Mbs) for in vivo positron emission tomography (PET)/magnetic resonance imaging (MRI) of CD4+ T cells in human xenografts, syngeneic tumor-bearing wild-type (WT), and human CD4+ knock-in (hCD4-KI) mouse models. Results: Both 89Zr-CD4-Mbs yielded high radiolabeling efficiencies of >90%, immunoreactivities of >70%, and specific in vitro binding to their target antigens. The specificity of in vivo targeting of 89Zr-hCD4-Mb was confirmed by PET/MRI, revealing ~4-fold greater 89Zr-hCD4-Mb uptake in subcutaneous hCD4+ hematopoietic peripheral blood acute lymphoblastic leukemia tumors (HPB-ALL) than in solid hCD4- diffuse histiocytic lymphomas (DHL) and 89Zr-mCD4-Mb uptake in hCD4+ HPB-ALL tumors. In a comparative cross-validation study in anti-programmed death ligand (αPD-L1)/anti-4-1BB-treated orthotopic PyMT mammary carcinoma-bearing hCD4-KI and WT mice, we detected 2- to 3-fold enhanced species-specific 89Zr-hCD4-Mb or 89Zr-mCD4-Mb uptake within CD4+ cell-enriched secondary lymphatic organs (lymph nodes and spleens). The 89Zr-hCD4-Mb uptake in the PyMT tumors was more pronounced in hCD4-KI mice compared to the WT control littermates. Most importantly, MC38 adenocarcinoma-bearing mice treated with a combination of αPD-L1 and anti-lymphocyte-activation gene 3 (αLag-3) antibodies exhibited ~1.4-fold higher 89Zr-mCD4-Mb uptake than mice that were not responsive to therapy or sham-treated mice. Conclusion: CD4 PET/MRI enabled monitoring of the CD4+ cell distribution in secondary lymphatic organs and the tumor microenvironment, capable of predicting sensitivity to CIT. Our imaging approach will provide deeper insights into the underlying molecular mechanisms of CD4-directed cancer immunotherapies in preclinical mouse models and is applicable for clinical translation.

IFNγ-Induced Bcl3, PD-L1 and IL-8 Signaling in Ovarian Cancer: Mechanisms and Clinical Significance

IFNγ, a pleiotropic cytokine produced not only by activated lymphocytes but also in response to cancer immunotherapies, has both antitumor and tumor-promoting functions. In ovarian cancer (OC) cells, the tumor-promoting functions of IFNγ are mediated by IFNγ-induced expression of Bcl3, PD-L1 and IL-8/CXCL8, which have long been known to have critical cellular functions as a proto-oncogene, an immune checkpoint ligand and a chemoattractant, respectively. However, overwhelming evidence has demonstrated that these three genes have tumor-promoting roles far beyond their originally identified functions. These tumor-promoting mechanisms include increased cancer cell proliferation, invasion, angiogenesis, metastasis, resistance to chemotherapy and immune escape. Recent studies have shown that IFNγ-induced Bcl3, PD-L1 and IL-8 expression is regulated by the same JAK1/STAT1 signaling pathway: IFNγ induces the expression of Bcl3, which then promotes the expression of PD-L1 and IL-8 in OC cells, resulting in their increased proliferation and migration. In this review, we summarize the recent findings on how IFNγ affects the tumor microenvironment and promotes tumor progression, with a special focus on ovarian cancer and on Bcl3, PD-L1 and IL-8/CXCL8 signaling. We also discuss promising novel combinatorial strategies in clinical trials targeting Bcl3, PD-L1 and IL-8 to increase the effectiveness of cancer immunotherapies.

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.

Deciphering CD4+ T cell-mediated responses against cancer

It's been long thought that CD8+ cytotoxic T cells play a major role in T cell-mediated antitumor responses, whereas CD4+ T cells merely provide some assistance to CD8+ T cells as the "helpers." In recent years, numerous studies support the notion that CD4+ T cells play an indispensable role in antitumor responses. Here, we summarize and discuss the current knowledge regarding the roles of CD4+ T cells in antitumor responses and immunotherapy, with a focus on the molecular and cellular mechanisms behind these observations. These new insights on CD4+ T cells may pave the way to further optimize cancer immunotherapy.

Spatial and functional targeting of intratumoral Tregs reverses CD8+ T cell exhaustion and promotes cancer immunotherapy

Intratumoral Tregs are key mediators of cancer immunotherapy resistance, including anti-programmed cell death (ligand) 1 [anti-PD-(L)1] immune checkpoint blockade (ICB). The mechanisms driving Treg infiltration into the tumor microenvironment (TME) and the consequence on CD8+ T cell exhaustion remain elusive. Here, we report that heat shock protein gp96 (also known as GRP94) was indispensable for Treg tumor infiltration, primarily through the roles of gp96 in chaperoning integrins. Among various gp96-dependent integrins, we found that only LFA-1 (αL integrin), and not αV, CD103 (αE), or β7 integrin, was required for Treg tumor homing. Loss of Treg infiltration into the TME by genetic deletion of gp96/LFA-1 potently induced rejection of tumors in multiple ICB-resistant murine cancer models in a CD8+ T cell-dependent manner, without loss of self-tolerance. Moreover, gp96 deletion impeded Treg activation primarily by suppressing IL-2/STAT5 signaling, which also contributed to tumor regression. By competing for intratumoral IL-2, Tregs prevented the activation of CD8+ tumor-infiltrating lymphocytes, drove thymocyte selection-associated high mobility group box protein (TOX) induction, and induced bona fide CD8+ T cell exhaustion. By contrast, Treg ablation led to striking CD8+ T cell activation without TOX induction, demonstrating clear uncoupling of the 2 processes. Our study reveals that the gp96/LFA-1 axis plays a fundamental role in Treg biology and suggests that Treg-specific gp96/LFA-1 targeting represents a valuable strategy for cancer immunotherapy without inflicting autoinflammatory conditions.

Critical role of the gut microbiota in immune responses and cancer immunotherapy

The gut microbiota plays a critical role in the progression of human diseases, especially cancer. In recent decades, there has been accumulating evidence of the connections between the gut microbiota and cancer immunotherapy. Therefore, understanding the functional role of the gut microbiota in regulating immune responses to cancer immunotherapy is crucial for developing precision medicine. In this review, we extract insights from state-of-the-art research to decipher the complicated crosstalk among the gut microbiota, the systemic immune system, and immunotherapy in the context of cancer. Additionally, as the gut microbiota can account for immune-related adverse events, we discuss potential interventions to minimize these adverse effects and discuss the clinical application of five microbiota-targeted strategies that precisely increase the efficacy of cancer immunotherapy. Finally, as the gut microbiota holds promising potential as a target for precision cancer immunotherapeutics, we summarize current challenges and provide a general outlook on future directions in this field.

Combination of IFN-gamma with STING agonist and PD-1 immune checkpoint blockade: a potential immunotherapy for gastric cancer

Suppression of the cGAS-STING pathway is an immune escape mechanism in cancer cells. The critical role of this pathway in gastric cancer (GC) is not fully understood. Herein, we evaluated the effect of the interferon-gamma (IFN-gamma), STING agonist, PD-1 immune checkpoint blockade, and their combination on the cGAS-STING pathway in GC. Expression of cGAS and STING in tumor tissue samples and adjacent normal tissue (ANT) biopsies of fifty new GC patients was evaluated by quantitative real-time PCR (qRT-PCR). Moreover, cGAS and STING expression levels were examined in Peripheral Blood Mononuclear Cells (PBMC) samples of forty GC patients and twenty-five healthy subjects. The apoptosis rate of cancer cells was analyzed by Annexin V-FITC/PI. Cell proliferation was measured by the BrdU assay. Also, IFN-β levels were evaluated in the supernatants of the treated groups. The cGAS expression was decreased in patients with distant metastasis. Co-cultures treated with IFN-gamma showed an elevated level of cGAS and STING expressions in PBMC and cancer cells. The rate of apoptosis increased in all the treatment groups. In addition, the rate of proliferation in PBMCs increased in different treated groups. The main role of PBMCs in cytotoxicity was determined by a comparative analysis of the viability of cells treated with all treatments, both with and without PBMCs. The production of IFN-β was elevated in all treated groups. The current study suggests that a combination therapy using IFN-gamma, STING agonist, and anti-PD-1 antibody can provide a promising approach to the treatment of GC.

Selective activation of IFNγ-ipilimumab enhances the therapeutic effect and safety of ipilimumab

INTRODUCTION

Immune checkpoint inhibitor therapy is a highly promising strategy for clinical treatment of cancer. Among these inhibitors, ipilimumab stands out for its ability to induce cytotoxic T cell proliferation and activation by binding to CTLA-4. However, ipilimumab also gives rise to systemic immune-related adverse effects and tumor immune evasion, limiting its effectiveness.

OBJECTIVES

We developed IFNγ-ipilimumab and confirmed that the addition of INF-γ does not alter the fundamental properties of ipilimumab.

RESULTS

IFNγ-ipilimumab can be activated by matrix metalloproteinases, thereby promoting the IFNγ signaling pathway and enhancing the cytotoxicity of T cells. In vivo studies demonstrated that IFNγ-ipilimumab enhances the therapeutic effect of ipilimumab against colorectal cancer by increasing CD8+ and CD4+ lymphocyte infiltration into the tumor area and inducing MHC-I expression in tumor cells. Mice treated with IFNγ-ipilimumab showed higher survival rates and body weight, as well as lower CD4+ and CD8+ lymphocyte activation rates in the blood and reduced organ damage.

CONCLUSION

IFNγ-ipilimumab improved the effectiveness of ipilimumab while reducing its side effects. It is likely that future immunotherapies would rely on such antibodies to activate local cancer cells or immune cells, thereby increasing the therapeutic effectiveness of cancer treatments and ensuring their safety.

ICOS costimulation in combination with CTLA-4 blockade remodels tumor-associated macrophages toward an antitumor phenotype

We have previously demonstrated synergy between ICOS costimulation (IVAX; ICOSL-transduced B16-F10 cellular vaccine) and CTLA-4 blockade in antitumor therapy. In this study, we employed CyTOF and single-cell RNA sequencing and observed significant remodeling of the lymphoid and myeloid compartments in combination therapy. Compared with anti-CTLA-4 monotherapy, the combination therapy enriched Th1 CD4 T cells, effector CD8 T cells, and M1-like antitumor proinflammatory macrophages. These macrophages were critical to the therapeutic efficacy of anti-CTLA-4 combined with IVAX or anti-PD-1. Macrophage depletion with clodronate reduced the tumor-infiltrating effector CD4 and CD8 T cells, impairing their antitumor functions. Furthermore, the recruitment and polarization of M1-like macrophages required IFN-γ. Therefore, in this study, we show that there is a positive feedback loop between intratumoral effector T cells and tumor-associated macrophages (TAMs), in which the IFN-γ produced by the T cells polarizes the TAMs into M1-like phenotype, and the TAMs, in turn, reshape the tumor microenvironment to facilitate T cell infiltration, immune function, and tumor rejection.

Non-IL-2-blocking anti-CD25 antibody inhibits tumor growth by depleting Tregs and has synergistic effects with anti-CTLA-4 therapy

CD25, also known as the interleukin-2 receptor α chain (IL-2Rα), is highly expressed on regulatory T cells (Tregs), but relatively lower on effector T cells (Teffs). This makes it a potential target for Treg depletion, which can be used in tumor immunotherapy. However, marketed anti-CD25 antibodies (Basiliximab and Daclizumab) were originally developed as immunosuppressive drugs to prevent graft rejection, because these antibodies can block IL-2 binding to CD25 on Teffs, which in turn destroys the function of Teffs. Recent studies have shown that non-IL-2-blocking anti-CD25 antibodies have displayed exciting antitumor effects. Here, we screened out a non-IL-2-blocking anti-CD25 monoclonal antibody (mAb) 7B7 by hybridoma technology, and confirmed its antitumor activity via depleting Tregs in a CD25 humanized mouse model. Subsequently, we verified that the humanized 7B7, named as h7B7-15S, has comparable activities to 7B7, and that its Treg depletion is further increased when combined with anti-CTLA-4, leading to enhanced remodeling of the tumor immune microenvironment. Moreover, our findings reveal that the Fab form of h7B7-15S has the ability to deplete Tregs, independent of the Fc region. Taken together, our studies expand the application of anti-CD25 in tumor immunotherapy and provide insight into the underlying mechanism.

Transcriptional profile and immune infiltration in colorectal cancer reveal the significance of inducible T-cell costimulator as a crucial immune checkpoint molecule

BACKGROUND

Emergence of novel immuno-therapeutics has shown promising improvement in the clinical outcome of colorectal cancer (CRC).

OBJECTIVE

To identify robust immune checkpoints based on expression and immune infiltration profiles of clinical CRC samples.

METHODS

One dataset from The Cancer Genome Atlas database and two from Gene Expression Omnibus were independently employed for the analysis. Genes associated with overall survival were identified, and distribution of each immune checkpoint with respect to different clinical features was determined to explore key immune checkpoints. Multiple staining methods were used to verify the correlation between key immune checkpoint ICOS and clinical pathological features. Differentially expressed mRNA and long non-coding RNA (lncRNA) were then detected for gene set enrichment analysis and gene set variation analysis to investigate the differentially enriched biological processes between low- and high-expression groups. Significant immune-related mRNAs and lncRNA were subjected to competing endogenous RNA (ceRNA) network analysis. Correlation of inducible T-cell costimulator (ICOS) and top 10 genes in ceRNA network were further considered for validation.

RESULTS

ICOS was identified from 14 immune checkpoints as the most highly correlated gene with survival and clinical features in CRC. The expression of ICOS protein in the poorly differentiated group was lower than that in the moderately differentiated group, and the expression in different pathological stages was significant. In addition, the expressions of ICOS were negatively correlated with Ki67. A conspicuous number of immune-related pathways were enriched in differentially expressed genes in the ICOS high- and low-expression groups. Integration with immune infiltration data revealed a multitude of differentially expressed immune-related genes enriched for ceRNA network. Furthermore, expression of top 10 genes investigated from ceRNA network showed high correlation with ICOS.

CONCLUSION

ICOS might serve as a robust immune checkpoint for prognosis with several genes being potential targets of ICOS-directed immunotherapy in CRC.

Tumor-localized interleukin-2 and interleukin-12 combine with radiation therapy to safely potentiate regression of advanced malignant melanoma in pet dogs

The clinical use of interleukin-2 and -12 cytokines against cancer is limited by their narrow therapeutic windows due to on-target, off-tumor activation of immune cells when delivered systemically. Engineering IL-2 and IL-12 to bind to extracellular matrix collagen allows these cytokines to be retained within tumors after intralesional injection, overcoming these clinical safety challenges. While this approach has potentiated responses in syngeneic mouse tumors without toxicity, the complex tumor-immune interactions in human cancers are difficult to recapitulate in mouse models of cancer. This has driven an increased role for comparative oncology clinical trials in companion (pet) dogs with spontaneous cancers that feature analogous tumor and immune biology to human cancers. Here, we report the results from a dose-escalation clinical trial of intratumoral collagen-binding IL-2 and IL-12 cytokines in pet dogs with malignant melanoma, observing encouraging local and regional responses to therapy that may suggest human clinical benefit with this approach.

PD-1 or CTLA-4 blockade promotes CD86-driven Treg responses upon radiotherapy of lymphocyte-depleted cancer in mice

Radiotherapy (RT) is considered immunogenic, but clinical data demonstrating RT-induced T cell priming are scarce. Here, we show in a mouse tumor model representative of human lymphocyte-depleted cancer that RT enhanced spontaneous priming of thymus-derived (FOXP3+Helios+) Tregs by the tumor. These Tregs acquired an effector phenotype, populated the tumor, and impeded tumor control by a simultaneous, RT-induced CD8+ cytotoxic T cell (CTL) response. Combination of RT with CTLA-4 or PD-1 blockade, which enables CD28 costimulation, further increased this Treg response and failed to improve tumor control. We discovered that upon RT, the CD28 ligands CD86 and CD80 differentially affected the Treg response. CD86, but not CD80, blockade prevented the effector Treg response, enriched the tumor-draining lymph node migratory conventional DCs that were positive for PD-L1 and CD80 (PD-L1+CD80+), and promoted CTL priming. Blockade of CD86 alone or in combination with PD-1 enhanced intratumoral CTL accumulation, and the combination significantly increased RT-induced tumor regression and OS. We advise that combining RT with PD-1 and/or CTLA-4 blockade may be counterproductive in lymphocyte-depleted cancers, since these interventions drive Treg responses in this context. However, combining RT with CD86 blockade may promote the control of such tumors by enabling a CTL response.

The future of targeting cytotoxic T-lymphocyte-associated protein-4: Is there a role?

The 2022 yearly Think Tank Meeting in Siena, Tuscany (Italy), organized by the Italian Network for Tumor Biotherapy (NIBIT) Foundation, the Parker Institute for Cancer Immunotherapy and the World Immunotherapy Council, included a focus on the future of integrating and expanding the use of targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). The conference members exchanged their views on the lessons from targeting CTLA-4 and compared the effect to the impact of blocking Programmed cell death protein 1 (PD1) or its ligand (PDL1). The increasing experience with both therapeutic approaches and their combination suggests that targeting CTLA-4 may lead to more durable responses for a sizeable proportion of patients, though the specific mechanism is not entirely understood. Overcoming toxicity of blocking CTLA-4 is currently being addressed with different doses and dose regimens, especially when combined with PD1/PDL1 blocking antibodies. Novel therapeutics targeting CTLA-4 hold the promise to reduce toxicities and thus allow different combination strategies in the future. On the whole, the consent was that targeting CTLA-4 remains an important strategy to improve the efficacy of cancer immunotherapies.

Multifaceted roles for BCL3 in cancer: a proto-oncogene comes of age

In the early 1990's a group of unrelated genes were identified from the sites of recurring translocations in B-cell lymphomas. Despite sharing the nomenclature 'Bcl', and an association with blood-borne cancer, these genes have unrelated functions. Of these genes, BCL2 is best known as a key cancer target involved in the regulation of caspases and other cell viability mechanisms. BCL3 on the other hand was originally identified as a non-canonical regulator of NF-kB transcription factor pathways - a signaling mechanism associated with important cell outcomes including many of the hallmarks of cancer. Most of the early investigations into BCL3 function have since focused on its role in NF-kB mediated cell proliferation, inflammation/immunity and cancer. However, recent evidence is coming to light that this protein directly interacts with and modulates a number of other signaling pathways including DNA damage repair, WNT/β-catenin, AKT, TGFβ/SMAD3 and STAT3 - all of which have key roles in cancer development, metastatic progression and treatment of solid tumours. Here we review the direct evidence demonstrating BCL3's central role in a transcriptional network of signaling pathways that modulate cancer biology and treatment response in a range of solid tumour types and propose common mechanisms of action of BCL3 which may be exploited in the future to target its oncogenic effects for patient benefit.

Mechanisms of immune checkpoint inhibitors: insights into the regulation of circular RNAS involved in cancer hallmarks

Current treatment strategies for cancer, especially advanced cancer, are limited and unsatisfactory. One of the most substantial advances in cancer therapy, in the last decades, was the discovery of a new layer of immunotherapy approach, immune checkpoint inhibitors (ICIs), which can specifically activate immune cells by targeting immune checkpoints. Immune checkpoints are a type of immunosuppressive molecules expressed on immune cells, which can regulate the degree of immune activation and avoid autoimmune responses. ICIs, such as anti-PD-1/PD-L1 drugs, has shown inspiring efficacy and broad applicability across various cancers. Unfortunately, not all cancer patients benefit remarkably from ICIs, and the overall response rates to ICIs remain relatively low for most cancer types. Moreover, the primary and acquired resistance to ICIs pose serious challenges to the clinical application of cancer immunotherapy. Thus, a deeper understanding of the molecular biological properties and regulatory mechanisms of immune checkpoints is urgently needed to improve clinical options for current therapies. Recently, circular RNAs (circRNAs) have attracted increasing attention, not only due to their involvement in various aspects of cancer hallmarks, but also for their impact on immune checkpoints in shaping the tumor immune microenvironment. In this review, we systematically summarize the current status of immune checkpoints in cancer and the existing regulatory roles of circRNAs on immune checkpoints. Meanwhile, we also aim to settle the issue in an evidence-oriented manner that circRNAs involved in cancer hallmarks regulate the effects and resistance of ICIs by targeting immune checkpoints.

Fcγ receptors and immunomodulatory antibodies in cancer

The discovery of both cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and programmed cell death protein 1 (PD1) as negative regulators of antitumour immunity led to the development of numerous immunomodulatory antibodies as cancer treatments. Preclinical studies have demonstrated that the efficacy of immunoglobulin G (IgG)-based therapies depends not only on their ability to block or engage their targets but also on the antibody's constant region (Fc) and its interactions with Fcγ receptors (FcγRs). Fc-FcγR interactions are essential for the activity of tumour-targeting antibodies, such as rituximab, trastuzumab and cetuximab, where the killing of tumour cells occurs at least in part due to these mechanisms. However, our understanding of these interactions in the context of immunomodulatory antibodies designed to boost antitumour immunity remains less explored. In this Review, we discuss our current understanding of the contribution of FcγRs to the in vivo activity of immunomodulatory antibodies and the challenges of translating results from preclinical models into the clinic. In addition, we review the impact of genetic variability of human FcγRs on the activity of therapeutic antibodies and how antibody engineering is being utilized to develop the next generation of cancer immunotherapies.

Turning up the heat: CTLA4 blockade in urothelial cancer

Anti-PD1 and anti-PDL1 monotherapies have shown clinical efficacy in stage IV urothelial cancer and are integrated into current clinical practice. However, only a small number of the patients treated with single-agent checkpoint blockade experience an antitumour response. Insufficient priming or inhibitory factors in the tumour immune microenvironment might have a role in the lack of response. CTLA4 is an inhibitory checkpoint on activated T cells that is being studied as a therapeutic target in combination with anti-PD1 or anti-PDL1 therapies in advanced urothelial cancer. In locally advanced urothelial cancer, this combination approach has shown encouraging antitumour effects when administered pre-operatively. We believe that the presence of pre-existing intratumoural T cell immunity is not a prerequisite for response to combination therapy and that the additional value of CTLA4 blockade might involve the broadening of peripheral T cell priming, thereby transforming immunologically cold tumours into hot tumours.

Immune checkpoint inhibitors and cancer immunotherapy by aptamers: an overview

Efforts in cancer immunotherapy aim to counteract evasion mechanisms and stimulate the immune system to recognise and attack cancer cells effectively. Combination therapies that target multiple aspects of immune evasion are being investigated to enhance the overall efficacy of cancer immunotherapy. PD-1 (Programmed Cell Death Protein 1), CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4), LAG-3 (Lymphocyte-Activation Gene 3), and TIM-3 (T Cell Immunoglobulin and Mucin Domain-Containing Protein3) are all immune checkpoint receptors that play crucial roles in regulating the immune response and maintaining self-tolerance often exploited by cancer cells to evade immune surveillance. Antibodies targeted against immune checkpoint inhibitors such as anti-PD-1 antibodies (e.g., pembrolizumab, nivolumab), anti-CTLA-4 antibodies (e.g., Ipilimumab), and experimental drugs targeting LAG-3 and TIM-3, aim to block these interactions and unleash the immune system's ability to recognise and destroy cancer cells. The US FDA has approved different categories of immune checkpoint inhibitors that have been utilised successfully in some patients with metastatic melanoma, renal cell carcinoma, head and neck cancers, and non-small lung cancer. Although several immune checkpoint inhibitor antibodies have been developed, they exhibited immune-related adverse effects, resulting in hypophysitis, diabetes, and neurological issues. These adverse effects of antibodies can be reduced by developing aptamer against the target. Aptamers offer several advantages over traditional antibodies, such as improved specificity, reduced immunogenicity, and flexible design for reduced adverse effects that specifically target and block protein-protein or receptor-ligand interactions involved in immune checkpoint pathways. The current study aims to review the function of particular immune checkpoint inhibitors along with developed aptamer-mediated antitumor cytotoxicity in cancer treatment.

Molecular and clinical characterization of ICOS expression in breast cancer through large-scale transcriptome data

ICOS (Inducible T Cell Costimulator), one of the co-stimulatory B7 superfamily members, was characterized as a co-stimulatory receptor for T-cell enhancement. However, the role of ICOS in breast cancer remains largely unknown. The present study systematically investigated the expression pattern and its relation to clinical characteristics and immunotherapy by integrating multiple clinical cohorts and large-scale gene expression data. This study included 2994 breast tumor samples with transcriptome data and matched clinical data. To make our findings more reliable, we set the TCGA cohort as the discovery set and the METABRIC cohort as the validation set. The expression of ICOS in breast cancer is strongly associated with major clinical and molecular characteristics. There is an association between higher ICOS expression and malignant subtypes and grades of tumors. In addition, gene ontology analysis based on genes significantly correlated with ICOS expression indicated that the expression of ICOS is mainly associated with immune responses and inflammation. We also observed strong correlations between ICOS and other promising immune-checkpoint molecules, including PD1, PDL1, CTLA4, and IDO1. Furthermore, we found that ICOS expression is associated with the response to anti-PDL1 immunotherapy and may serve as a biomarker for immunotherapy prediction. Our results indicated higher ICOS expression is significantly associated with favorable survival in triple-negative breast cancer (TNBC) patients, but not for all subtypes of breast cancer patients. In summary, ICOS correlates with higher malignant breast cancers, and it contributes to the regulation of the immune microenvironment of breast tumors, making it a potential biomarker and immunotherapy target.

The role of CD4+ T cells in tumor and chronic viral immune responses

Immunotherapies are mainly aimed to promote a CD8+ T cell response rather than a CD4+ T cell response as cytotoxic T lymphocytes (CTLs) can directly kill target cells. Recently, CD4+ T cells have received more attention due to their diverse roles in tumors and chronic viral infections. In antitumor and antichronic viral responses, CD4+ T cells relay help signals through dendritic cells to indirectly regulate CD8+ T cell response, interact with B cells or macrophages to indirectly modulate humoral immunity or macrophage polarization, and inhibit tumor blood vessel formation. Additionally, CD4+ T cells can also exhibit direct cytotoxicity toward target cells. However, regulatory T cells exhibit immunosuppression and CD4+ T cells become exhausted, which promote tumor progression and chronic viral persistence. Finally, we also outline immunotherapies based on CD4+ T cells, including adoptive cell transfer, vaccines, and immune checkpoint blockade. Overall, this review summarizes diverse roles of CD4+ T cells in the antitumor or protumor and chronic viral responses, and also highlights the immunotherapies based on CD4+ T cells, giving a better understanding of their roles in tumors and chronic viral infections.

CD39+ conventional CD4+ T cells with exhaustion traits and cytotoxic potential infiltrate tumors and expand upon CTLA-4 blockade

Conventional CD4+ T (Tconv) lymphocytes play important roles in tumor immunity; however, their contribution to tumor elimination remains poorly understood. Here, we describe a subset of tumor-infiltrating Tconv cells characterized by the expression of CD39. In several mouse cancer models, we observed that CD39+ Tconv cells accumulated in tumors but were absent in lymphoid organs. Compared to tumor CD39- counterparts, CD39+ Tconv cells exhibited a cytotoxic and exhausted signature at the transcriptomic level, confirmed by high protein expression of inhibitory receptors and transcription factors related to the exhaustion. Additionally, CD39+ Tconv cells showed increased production of IFNγ , granzyme B, perforin and CD107a expression, but reduced production of TNF. Around 55% of OVA-specific Tconv from B16-OVA tumor-bearing mice, expressed CD39. In vivo CTLA-4 blockade induced the expansion of tumor CD39+ Tconv cells, which maintained their cytotoxic and exhausted features. In breast cancer patients, CD39+ Tconv cells were found in tumors and in metastatic lymph nodes but were less frequent in adjacent non-tumoral mammary tissue and not detected in non-metastatic lymph nodes and blood. Human tumor CD39+ Tconv cells constituted a heterogeneous cell population with features of exhaustion, high expression of inhibitory receptors and CD107a. We found that high CD4 and ENTPD1 (CD39) gene expression in human tumor tissues correlated with a higher overall survival rate in breast cancer patients. Our results identify CD39 as a biomarker of Tconv cells, with characteristics of both exhaustion and cytotoxic potential, and indicate CD39+ Tconv cells as players within the immune response against tumors.

Mechanisms underlying response and resistance to immune checkpoint blockade in cancer immunotherapy

Cancer immunotherapies targeting immune checkpoint pathways, such as programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4), have achieved unprecedented therapeutic success in treating various types of cancer. The prominent and persistent clinical responses to immune checkpoint blockade (ICB) therapy are currently constrained to a subset of patients. Owing to discrete individual tumor and immune heterogeneity, most patients fail to benefit from ICB treatment, demonstrating either primary or acquired resistance. A thorough comprehension of the mechanisms restricting the efficacy of immune checkpoint inhibitors (ICIs) is required to extend their clinical applicability to a broader spectrum of patients and cancer types. Numerous studies are presently investigating potential prognostic markers of responsiveness, the complex dynamics underlying the therapeutic and adverse effects of ICB, and tumor immune evasion throughout the course of immunotherapy. In this article, we have reviewed the extant literature elucidating the mechanisms underlying the response and resistance to ICB, with a particular emphasis on PD-1 and CTLA-4 pathway blockade in the context of anti-tumor immunity. Furthermore, we aimed to explore potential approaches to overcome cancer therapeutic resistance and develop a rational design for more personalized ICB-based combinational regimens.

Case Report: Immune checkpoint inhibitor-induced multiorgan vasculitis successfully treated with rituximab

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of cancer. ICIs have a unique side effect profile, generally caused by inflammatory tissue damage, with clinical features similar to autoimmune conditions. Acute kidney injury from ICIs has been well studied; incidence ranges from 1% to 5%, with higher incidence when combination ICI therapies are used. Although the overall reported incidence of ICI-associated glomerulonephritis is less than 1%, vasculitis is the most commonly reported ICI-related glomerulonephritis. Other biopsy findings include thrombotic microangiopathy, focal segmental glomerulosclerosis, minimal change disease, and IgA nephropathy with secondary amyloidosis. We report a case in which a woman previously treated with the PD-L1 inhibitor durvalumab for locally advanced non-small cell lung cancer with pre-existing antineutrophil cytoplasmic (anti-PR3) antibody who later developed multi-organ vasculitis after ICI exposure, which was successfully treated with rituximab, with continued cancer remission for 3 years.

Muscle invasive bladder cancer: where is the field headed?

INTRODUCTION

The standard treatment for muscle-invasive bladder cancer (MIBC) is cisplatin-based neoadjuvant chemotherapy (NAC) followed by radical cystectomy or upfront radical cystectomy for cisplatin-ineligible patients. In those who are ineligible for or refuse radical cystectomy, trimodal therapy with chemoradiation is offered. However, with the success of immune checkpoint inhibitors (ICI) and antibody-drug conjugates such as enfortumab vedotin in the metastatic setting, several trials are implementing these drugs in the neoadjuvant setting for cisplatin ineligible patients. Indeed, nivolumab is approved as adjuvant therapy for high-risk muscle-invasive urothelial carcinoma.

AREAS COVERED

Clinical trials using ICI, ICI/ICI, and ICI/chemotherapy combination therapies in the perioperative setting have been completed. These clinical trials have demonstrated that neoadjuvant ICI are safe and have encouraging pCR, making them promising treatment options. Neoadjuvant enfortumab vedotin alone and in combination with pembrolizumab is also being studied, and preliminarily to have promising activity. ICI is also being combined with radiation therapy (RT) and early data indicate that ICI combined with RT or chemo-RT may be safe with promising activity.

EXPERT OPINION

Biomarkers are urgently needed to identify appropriate treatment options for individual patients. The use of novel treatment approaches and biomarkers will help shape the future of precision therapy for MIBC and enable bladder preservation.

ICOS DNA methylation regulates melanoma cell-intrinsic ICOS expression, is associated with melanoma differentiation, prognosis, and predicts response to immune checkpoint blockade

BACKGROUND

Inducible T cell costimulator ICOS is an emerging target in immuno-oncology. The aim of this study was to investigate the epigenetic regulation of ICOS in melanoma by DNA methylation.

METHODS

We comprehensively investigate ICOS DNA methylation of specific CpG sites and expression pattern within the melanoma microenvironment with regard to immune correlates, differentiation, clinical outcomes, and immune checkpoint blockade (ICB) response.

RESULTS

Our study revealed a sequence-contextual CpG methylation pattern consistent with an epigenetically regulated gene. We found a cell type-specific methylation pattern and locus-specific correlations and associations of CpG methylation with ICOS mRNA expression, immune infiltration, melanoma differentiation, prognosis, and response to ICB. High ICOS mRNA expression was identified as a surrogate for enriched immune cell infiltration and was associated with favorable overall survival (OS) in non-ICB-treated patients and predicted response and a prolonged progression-free survival (PFS) following ICB therapy initiation. ICOS hypomethylation, however, significantly correlated with poor OS in non-ICB patients but predicted higher response and prolonged PFS and OS in ICB-treated patients. Moreover, we observed cytoplasmic and sporadically nuclear tumor cell-intrinsic ICOS protein expression. Tumor cell-intrinsic ICOS protein and mRNA expression was inducible by pharmacological demethylation with decitabine.

CONCLUSION

Our study identified ICOS DNA methylation and mRNA expression as promising prognostic and predictive biomarkers for immunotherapy in melanoma and points towards a hitherto undescribed role of ICOS in tumor cells.

Activated CTLA-4-independent immunosuppression of Treg cells disturbs CTLA-4 blockade-mediated antitumor immunity

Combination therapy with anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and anti-programmed death-1 (PD-1) monoclonal antibodies (mAbs) has dramatically improved the prognosis of patients with multiple types of cancer, including renal cell carcinoma (RCC). However, more than half of RCC patients fail to respond to this therapy. Regulatory T cells (Treg cells) are a subset of highly immunosuppressive CD4+ T cells that promote the immune escape of tumors by suppressing effector T cells in the tumor microenvironment (TME) through various mechanisms. CTLA-4 is constitutively expressed in Treg cells and is regarded as a key molecule for Treg-cell-mediated immunosuppressive functions, suppressing antigen-presenting cells by binding to CD80/CD86. Reducing Treg cells in the TME with an anti-CTLA-4 mAb with antibody-dependent cellular cytotoxicity (ADCC) activity is considered an essential mechanism to achieve tumor regression. In contrast, we demonstrated that CTLA-4 blockade without ADCC activity enhanced CD28 costimulatory signaling pathways in Treg cells and promoted Treg-cell proliferation in mouse models. CTLA-4 blockade also augmented CTLA-4-independent immunosuppressive functions, including cytokine production, leading to insufficient antitumor effects. Similar results were also observed in human peripheral blood lymphocytes and tumor-infiltrating lymphocytes from patients with RCC. Our findings highlight the importance of Treg-cell depletion to achieve tumor regression in response to CTLA-4 blockade therapies.

Dual IL-6 and CTLA-4 blockade regresses pancreatic tumors in a T cell- and CXCR3-dependent manner

This study aimed to enhance antitumor immune responses to pancreatic cancer via Ab-based blockade of IL-6 and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Mice bearing s.c. or orthotopic pancreatic tumors were treated with blocking Abs to IL‑6 and/or CTLA-4. In both tumor models, dual IL-6 and CTLA-4 blockade significantly inhibited tumor growth. Additional investigations revealed that dual therapy induced an overwhelming infiltration of T cells into the tumor as well as changes in CD4+ T cell subsets. Dual blockade therapy elicited CD4+ T cells to secrete increased IFN-γ in vitro. Likewise, in vitro stimulation of pancreatic tumor cells with IFN-γ profoundly increased tumor cell production of CXCR3-specific chemokines, even in the presence of IL-6. In vivo blockade of CXCR3 prevented orthotopic tumor regression in the presence of the combination treatment, demonstrating a dependence on the CXCR3 axis for antitumor efficacy. Both CD4+ and CD8+ T cells were required for the antitumor activity of this combination therapy, as their in vivo depletion via Abs impaired outcomes. These data represent the first report to our knowledge of IL-6 and CTLA‑4 blockade as a means to regress pancreatic tumors with defined operative mechanisms of efficacy.

Immune checkpoint therapy-current perspectives and future directions

Immune checkpoint therapy (ICT) has dramatically altered clinical outcomes for cancer patients and conferred durable clinical benefits, including cure in a subset of patients. Varying response rates across tumor types and the need for predictive biomarkers to optimize patient selection to maximize efficacy and minimize toxicities prompted efforts to unravel immune and non-immune factors regulating the responses to ICT. This review highlights the biology of anti-tumor immunity underlying response and resistance to ICT, discusses efforts to address the current challenges with ICT, and outlines strategies to guide the development of subsequent clinical trials and combinatorial efforts with ICT.

Role of T cells in cancer immunotherapy: Opportunities and challenges

Immunotherapies boosting the immune system's ability to target cancer cells are promising for the treatment of various tumor types, yet clinical responses differ among patients and cancers. Recently, there has been increasing interest in novel cancer immunotherapy practices aimed at triggering T cell-mediated anti-tumor responses. Antigen-directed cytotoxicity mediated by T lymphocytes has become a central focal point in the battle against cancer utilizing the immune system. The molecular and cellular mechanisms involved in the actions of T lymphocytes have directed new therapeutic approaches in cancer immunotherapy, including checkpoint blockade, adoptive and chimeric antigen receptor (CAR) T cell therapy, and cancer vaccinology. This review addresses all the strategies targeting tumor pathogenesis, including metabolic pathways, to evaluate the clinical significance of current and future immunotherapies for patients with cancer, which are further engaged in T cell activation, differentiation, and response against tumors.

Vascular Normalization Was Associated with Colorectal Tumor Regression upon Anti-PD-L1 Combinational Therapy

Anti-PD-L1 therapy exhibits durable efficacy, but only in a small fraction of cancer patients. The immunosuppressive tumor microenvironment (TME) is a crucial obstacle that impedes cancer immunotherapy. Here, we found that anti-PD-L1 therapy coupled with CD4+ T cell depletion induced colorectal tumor regression and vascular normalization, while monotherapy only retarded tumor growth without affecting the tumor vasculature. Moreover, simultaneous PD-L1 blockade and CD4+ T cell depletion eradicated intratumoral PD-L1+ lymphoid and myeloid cell populations, while additively elevating the proportions of CD44+CD69+CD8+, central memory CD44+CD62L+CD8+, and effector memory CD44+CD62L-CD8+ T cells, suggesting a reduction in immunosuppressive cell populations and the activation of CD8+ T cells in the TME. Moreover, anti-PD-L1 therapy reduced the proportions of intratumoral PD-L1+ immune cells and suppressed tumor growth in a CD8+ T cell dependent manner. Together, these results suggest that anti-PD-L1 therapy induces tumor vascular normalization and colorectal tumor regression via CD8+ T cells, which is antagonized by CD4+ T cells. Our findings unveil the positive correlation of tumor regression and vascular normalization in colorectal tumor models upon anti-PD-L1 therapy, providing a potential new strategy to improve its efficacy.

Immune checkpoint therapy: Forging ahead

Spatiotemporal immune monitoring in clinical trials and reverse translation will help to determine optimal combination immune therapies to cure cancer.

Distinct pretreatment innate immune landscape and posttreatment T cell responses underlie immunotherapy-induced colitis

Immune-related adverse events represent a major hurdle to the success of immunotherapy. The immunological mechanisms underlying their development and relation to antitumor responses are poorly understood. By examining both systemic and tissue-specific immune changes induced by combination anti-CTLA-4 and anti-PD-1 immunotherapy, we found distinct repertoire changes in patients who developed moderate-severe colitis, irrespective of their antitumor response to therapy. The proportion of circulating monocytes were significantly increased at baseline in patients who subsequently developed colitis compared with patients who did not develop colitis, and biopsies from patients with colitis showed monocytic infiltration of both endoscopically and histopathologically normal and inflamed regions of colon. The magnitude of systemic expansion of T cells following commencement of immunotherapy was also greater in patients who developed colitis. Importantly, we show expansion of specific T cell subsets within inflamed regions of the colon, including tissue-resident memory CD8+ T cells and Th1 CD4+ T cells in patients who developed colitis. Our data also suggest that CD8+ T cell expansion was locally induced, while Th1 cell expansion was systemic. Together, our data show that exaggerated innate and T cell responses to combination immunotherapy synergize to propel colitis in susceptible patients.