Systemic Interferon-γ Increases MHC Class I Expression and T-cell Infiltration in Cold Tumors: Results of a Phase 0 Clinical Trial

Transcriptomic observations of intra and extracellular immunotherapy targets for pediatric brain tumors

OBJECTIVES

Despite surgical resection, chemoradiation, and targeted therapy, brain tumors remain a leading cause of cancer-related death in children. Immunotherapy has shown some promise and is actively being investigated for treating childhood brain tumors. However, a critical step in advancing immunotherapy for these patients is to uncover targets that can be effectively translated into therapeutic interventions.

METHODS

In this study, our team performed a transcriptomic analysis across pediatric brain tumor types to identify potential targets for immunotherapy. Additionally, we assessed components that may impact patient response to immunotherapy, including the expression of genes essential for antigen processing and presentation, inhibitory ligands and receptors, interferon signature, and overall predicted T cell infiltration.

RESULTS

We observed distinct expression patterns across tumor types. These included elevated expression of antigen genes and antigen processing machinery in some tumor types while other tumors had elevated inhibitory checkpoint receptors, known to be associated with response to checkpoint inhibitor immunotherapy.

CONCLUSION

These findings suggest that pediatric brain tumors exhibit distinct potential for specific immunotherapies. We believe our findings can guide investigators in their assessment of appropriate immunotherapy classes and targets in pediatric brain tumors.

B7-H3 is widely expressed in soft tissue sarcomas

PURPOSE

Targeted therapy development in soft tissue sarcoma (STS) has been burdened by the heterogeneity of this group of rare tumors. B7 homolog 3 protein (B7-H3) is a molecule in the same family as programmed death-ligand 1 (PD-L1). It has limited expression in noncancerous tissues and is overexpressed in many cancers, making it an attractive target for cancer therapy, and clinical trials targeting B7-H3 are actively underway. While available data demonstrate high expression levels of B7-H3 in individual sarcoma subtypes, its expression patterns across STS subtypes are not well described. The purpose of this study was to characterize the expression patterns of B7-H3 in STS.

PATIENTS AND METHODS

This retrospective analysis evaluated STS tumor specimens from patients with a variety of different subtypes. Specimens were evaluated by immunohistochemistry (IHC) for expression and staining pattern of B7-H3 both in tumors and in associated vasculature.

RESULTS

Specimens from 153 sarcoma patients included 15 different STS subtypes. B7-H3 was broadly expressed in 97% of samples (95% CI 0.93-0.99) and 69.2% demonstrated high levels of B7-H3 expression (95% CI 0.61-0.76). No significant association between B7-H3 positivity or expression level and prior treatment(s), tumor size, tumor grade, or patient age. B7-H3 positivity in vessels was found in 94.7% (145/153) of samples. In tumors that had been previously assessed for PD-L1 and PD-1, there was no correlation between B7-H3 positivity or expression and the positivity or expression level of PD-L1 or PD-1.

CONCLUSION

These data show high levels of B7-H3 positivity across soft tissue sarcoma subtypes, suggesting its feasibility as a therapeutic target for future sarcoma treatments. Future clinical trials are needed to evaluate whether targeting B7-H3 can provide clinical benefit to help patients with sarcoma.

Improving tumor microenvironment assessment in chip systems through next-generation technology integration

The tumor microenvironment (TME) comprises a diverse array of cells, both cancerous and non-cancerous, including stromal cells and immune cells. Complex interactions among these cells play a central role in driving cancer progression, impacting critical aspects such as tumor initiation, growth, invasion, response to therapy, and the development of drug resistance. While targeting the TME has emerged as a promising therapeutic strategy, there is a critical need for innovative approaches that accurately replicate its complex cellular and non-cellular interactions; the goal being to develop targeted, personalized therapies that can effectively elicit anti-cancer responses in patients. Microfluidic systems present notable advantages over conventional in vitro 2D co-culture models and in vivo animal models, as they more accurately mimic crucial features of the TME and enable precise, controlled examination of the dynamic interactions among multiple human cell types at any time point. Combining these models with next-generation technologies, such as bioprinting, single cell sequencing and real-time biosensing, is a crucial next step in the advancement of microfluidic models. This review aims to emphasize the importance of this integrated approach to further our understanding of the TME by showcasing current microfluidic model systems that integrate next-generation technologies to dissect cellular intra-tumoral interactions across different tumor types. Carefully unraveling the complexity of the TME by leveraging next generation technologies will be pivotal for developing targeted therapies that can effectively enhance robust anti-tumoral responses in patients and address the limitations of current treatment modalities.

Craters on the melanoma surface facilitate tumor-immune interactions and demonstrate pathologic response to checkpoint blockade in humans

Immunotherapy leads to cancer eradication despite the tumor's immunosuppressive environment. Here, we used extended long-term in-vivo imaging and high-resolution spatial transcriptomics of endogenous melanoma in zebrafish, and multiplex imaging of human melanoma, to identify domains that facilitate immune response during immunotherapy. We identified crater-shaped pockets at the margins of zebrafish and human melanoma, rich with beta-2 microglobulin (B2M) and antigen recognition molecules. The craters harbor the highest density of CD8+ T cells in the tumor. In zebrafish, CD8+ T cells formed prolonged interactions with melanoma cells within craters, characteristic of antigen recognition. Following immunostimulatory treatment, the craters enlarged and became the major site of activated CD8+ T cell accumulation and tumor killing that was B2M dependent. In humans, craters predicted immune response to ICB therapy, showing response better than high T cell infiltration. This marks craters as potential new diagnostic tool for immunotherapy success and targets to enhance ICB response.

Single-cell transcriptomic sequencing analysis of mechanistic insights into the IFN-γ signaling pathway in different tumor cells

PURPOSE

This study aimed to investigate the relationship between the interferon-gamma (IFN-γ) pathway in different tumor microenvironments (TME) and patients' prognosis, as well as the regulatory mechanisms of this pathway in tumor cells.

METHODS

Using RNA-seq data from the TCGA database, we analyzed the predictive value of the IFN-γ pathway across various tumors. We employed a univariate Cox regression model to assess the prognostic significance of IFN-γ signaling in different tumor types. Additionally, we analyzed single-cell RNA sequencing (scRNA-seq) data from the Gene Expression Omnibus (GEO) database to examine the distribution characteristics of the IFN-γ pathway and explore its regulatory mechanisms, highlighting how IFN-γ influenced cellular interactions within the TME.

RESULTS

Our analysis revealed a significant association between the IFN-γ pathway and adverse prognosis in pan-cancer tissues (P < 0.001). Interestingly, this correlation varied regarding positive and negative regulation across different tumor types. Through a detailed examination of scRNA-seq data, we found that the IFN-γ pathway exerted substantial regulatory effects on stromal and immune cells. In contrast, its expression and regulatory patterns in tumor cells exhibited diversity and heterogeneity. Further analysis indicated that the IFN-γ pathway not only enhanced the immunogenicity of tumor cells but also inhibited their proliferation. Cell-cell interaction analysis confirmed the pivotal role of the IFN-γ pathway within the overall regulatory network. Moreover, we identified HMGB2 (high mobility group box 2) in T cells as a potential key regulator of tumor cell proliferation.

CONCLUSIONS

The IFN-γ pathway exhibited a dual function by both suppressing tumor cell proliferation and enhancing their immunogenicity, positioning it as a pivotal target for refined cancer diagnosis and cancer strategies.

Targeting cytokine and chemokine signaling pathways for cancer therapy

Cytokines are critical in regulating immune responses and cellular behavior, playing dual roles in both normal physiology and the pathology of diseases such as cancer. These molecules, including interleukins, interferons, tumor necrosis factors, chemokines, and growth factors like TGF-β, VEGF, and EGF, can promote or inhibit tumor growth, influence the tumor microenvironment, and impact the efficacy of cancer treatments. Recent advances in targeting these pathways have shown promising therapeutic potential, offering new strategies to modulate the immune system, inhibit tumor progression, and overcome resistance to conventional therapies. In this review, we summarized the current understanding and therapeutic implications of targeting cytokine and chemokine signaling pathways in cancer. By exploring the roles of these molecules in tumor biology and the immune response, we highlighted the development of novel therapeutic agents aimed at modulating these pathways to combat cancer. The review elaborated on the dual nature of cytokines as both promoters and suppressors of tumorigenesis, depending on the context, and discussed the challenges and opportunities this presents for therapeutic intervention. We also examined the latest advancements in targeted therapies, including monoclonal antibodies, bispecific antibodies, receptor inhibitors, fusion proteins, engineered cytokine variants, and their impact on tumor growth, metastasis, and the tumor microenvironment. Additionally, we evaluated the potential of combining these targeted therapies with other treatment modalities to overcome resistance and improve patient outcomes. Besides, we also focused on the ongoing research and clinical trials that are pivotal in advancing our understanding and application of cytokine- and chemokine-targeted therapies for cancer patients.

Cotargeting EBV lytic as well as latent cycle antigens increases T-cell potency against lymphoma

ABSTRACT

The remarkable efficacy of Epstein-Barr virus (EBV)-specific T cells for the treatment of posttransplant lymphomas has not been reproduced for EBV-positive (EBV+) malignancies outside the transplant setting. This is because of, in part, the heterogeneous expression and poor immunogenicity of the viral antigens expressed, namely latent membrane proteins 1 and 2, EBV nuclear antigen 1, and BamHI A rightward reading frame 1 (type-2 [T2] latency). However, EBV lytic cycle proteins are also expressed in certain EBV+ malignancies and, because several EBV lytic cycle proteins are abundantly expressed, have oncogenic activity, and likely contribute to malignancy, we sought and identified viral lytic-cycle transcripts in EBV+ Hodgkin lymphoma biopsies. This provided the rationale for broadening the target antigen-specific repertoire of EBV-specific T cells (EBVSTs) for therapy. We stimulated, peripheral blood mononuclear cells from healthy donors and patients with EBV+ lymphoma with both lytic and latent cycle proteins to produce broad repertoire (BR) EBVSTs. Compared with T2 antigen-specific EBVSTs, BR-EBVSTs more rapidly cleared autologous EBV+ tumors in NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice and produced higher levels of proinflammatory cytokines that should reactivate the immunosuppressive tumor microenvironment leading to epitope spreading. Our results confirm that lytic cycle antigens are clinically relevant targets for EBV+ lymphoma and underpin the rationale for integrating BR-EBVSTs as a therapeutic approach for relapsed/refractory EBV+ lymphoma (www.clinicaltrials.gov identifiers: #NCT01555892 and #NCT04664179), as well as for other EBV-associated malignancies.

Tumor Regression Following Engineered Polyomavirus-Specific T Cell Therapy in Immune Checkpoint Inhibitor-Refractory Merkel Cell Carcinoma

Although immune check-point inhibitors (CPIs) revolutionized treatment of Merkel cell carcinoma (MCC), patients with CPI-refractory MCC lack effective therapy. More than 80% of MCC express T-antigens encoded by Merkel cell polyomavirus, which is an ideal target for T-cell receptor (TCR)-based immunotherapy. However, MCC often repress HLA expression, requiring additional strategies to reverse the downregulation for allowing T cells to recognize their targets. We identified TCRMCC1 that recognizes a T-antigen epitope restricted to human leukocyte antigen (HLA)-A*02:01. Seven CPI-refractory metastatic MCC patients received CD4 and CD8 T cells transduced with TCRMCC1 (TTCR-MCC1) preceded either by lymphodepleting chemotherapy or an HLA-upregulating regimen (single-fraction radiation therapy (SFRT) or systemic interferon gamma (IFNγ)) with concurrent avelumab. Two patients who received preceding SFRT and IFNγ respectively experienced tumor regression. One experienced regression of 13/14 subcutaneous lesions with 1 'escape' lesion and the other had delayed tumor regression in all lesions after initial progression. Although TTCR-MCC1 cells with an activated phenotype infiltrated tumors including the 'escape' lesion, all progressing lesions transcriptionally lacked HLA expression. While SFRT/IFNγ did not immediately upregulate tumor HLA expression, a secondary endogenous antigen-specific T cell infiltrate was detected in one of the regressing tumors and associated with HLA upregulation, indicating in situ immune responses have the potential to reverse HLA downregulation. Indeed, supplying a strong co-stimulatory signal via a CD200R-CD28 switch receptor allows TTCR-MCC1 cells to control HLA-downregulated MCC cells in a xenograft mouse model, upregulating HLA expression. Our results demonstrate the potential of TCR gene therapy for metastatic MCC and propose a next strategy for overcoming epigenetic downregulation of HLA in MCC.

Near-infrared photoimmunotherapy targeting PD-L1: Improved efficacy by preconditioning the tumor microenvironment

Near-infrared photoimmunotherapy (NIR-PIT) is a new type of cancer therapy that employs antibody-IRDye700DX conjugates (AbPCs) and near-infrared (NIR) light at a wavelength of 689 nm, the excitation wavelength of IR700. Administered intravenously, injected AbPCs bind specifically to cells expressing the target antigen, whereupon NIR light exposure causes rapid, selective killing. This process induces an anticancer T cell response, leading to sustained anticancer host immune response. Programmed cell death ligand-1 (PD-L1) is a major inhibitory immune checkpoint molecule expressed in various cancers. In this study, we first assessed the efficacy of PD-L1-targeted NIR-PIT (αPD-L1-PIT) in immune-competent tumor mouse models. αPD-L1-PIT showed a significant therapeutic effect on the tumor models with high PD-L1 expression. Furthermore, αPD-L1-PIT induced an abscopal effect on distant tumors and long-term immunological memory. In contrast, αPD-L1-PIT was not as effective for tumor models with low PD-L1 expression. To improve the efficacy of PD-L1-targeted NIR-PIT, PEGylated interferon-gamma (IFNγ) was administered with αPD-L1-PIT. The combination therapy improved the treatment efficacy by increasing PD-L1 expression leading to more efficient cell killing by αPD-L1-PIT. Furthermore, the PEGylated IFNγ led to a CD8+ T cell-dominant tumor microenvironment (TME) with an enhanced anticancer T cell response after αPD-L1-PIT. As a result, even so-called cold tumors exhibited complete responses after αPD-L1-PIT. Thus, combination therapy of PEGylated IFNγ and PD-L1-targeted NIR-PIT has the potential to be an important future strategy for cancer immunotherapy.

HLA-A+ tertiary lymphoid structures with reactivated tumor infiltrating lymphocytes are associated with a positive immunotherapy response in esophageal squamous cell carcinoma

BACKGROUND

Immune checkpoint blockade (ICB) therapy provides remarkable clinical benefits for multiple cancer types. However, the overall response rate to ICB therapy remains low in esophageal squamous cell carcinoma (ESCC). This study aimed to identify biomarkers of ICB therapy for ESCC and interrogate its potential clinical relevance.

METHODS

We investigated gene expression in 42 treatment-naïve ESCC tumor tissues and identified differentially expressed genes, tumor-infiltrating lymphocytes and immune-related genes signatures associated with differential immunotherapy responses. We systematically assessed the tumor microenvironment using the NanoString GeoMx digital spatial profiler, single-cell RNA-seq and multiplex immunohistochemistry in ESCC. Finally, we evaluated the associations between HLA-A-positive tertiary lymphoid structures (TLSs) and patients' responses to ICB in 60 ESCC patients.

RESULTS

Tumor infiltrating B lymphocytes and several immune-related gene signatures, such as the antigen presenting machinery (APM) signature, are significantly elevated in ICB treatment responders. Multiplex immunohistochemistry identified the presence of HLA-A+ TLSs and showed that TLS-resident cells increasingly express HLA-A as TLSs mature. Most TLS-resident HLA-A+ cells are tumor-infiltrating T (TIL-T) or tumor-infiltrating B (TIL-B) lymphocytes. Digital spatial profiling of spatially distinct TIL-T lymphocytes and single-cell RNA-seq data from 60 ESCC tumor tissues revealed that CXCL13-expressing exhausted TIL-Ts inside TLSs are reactivated with elevated expression of the APM signature as TLSs mature. Finally, we demonstrated that HLA-A+ TLSs and their major cellular components, TIL-Ts and TIL-Bs, are associated with a clinical benefit from ICB treatment for ESCC.

CONCLUSIONS

HLA-A+ TLSs are present in ESCC tumor tissues. TLS-resident TIL-Ts with elevated expression of the APM signature may be reactivated. HLA-A+ TLSs and their major cellular components, TIL-Ts and TIL-Bs, may serve as biomarkers for ICB-treated ESCC patients.

Shifting cold to hot tumors by nanoparticle-loaded drugs and products

Cold tumors lack antitumor immunity and are resistant to therapy, representing a major challenge in cancer medicine. Because of the immunosuppressive spirit of the tumor microenvironment (TME), this form of tumor has a low response to immunotherapy, radiotherapy, and also chemotherapy. Cold tumors have low infiltration of immune cells and a high expression of co-inhibitory molecules, such as immune checkpoints and immunosuppressive molecules. Therefore, targeting TME and remodeling immunity in cold tumors can improve the chance of tumor repression after therapy. However, tumor stroma prevents the infiltration of inflammatory cells and hinders the penetration of diverse molecules and drugs. Nanoparticles are an intriguing tool for the delivery of immune modulatory agents and shifting cold to hot tumors. In this review article, we discuss the mechanisms underlying the ability of nanoparticles loaded with different drugs and products to modulate TME and enhance immune cell infiltration. We also focus on newest progresses in the design and development of nanoparticle-based strategies for changing cold to hot tumors. These include the use of nanoparticles for targeted delivery of immunomodulatory agents, such as cytokines, small molecules, and checkpoint inhibitors, and for co-delivery of chemotherapy drugs and immunomodulatory agents. Furthermore, we discuss the potential of nanoparticles for enhancing the efficacy of cancer vaccines and cell therapy for overcoming resistance to treatment.

Engineering allorejection-resistant CAR-NKT cells from hematopoietic stem cells for off-the-shelf cancer immunotherapy

The clinical potential of current FDA-approved chimeric antigen receptor (CAR)-engineered T (CAR-T) cell therapy is encumbered by its autologous nature, which presents notable challenges related to manufacturing complexities, heightened costs, and limitations in patient selection. Therefore, there is a growing demand for off-the-shelf universal cell therapies. In this study, we have generated universal CAR-engineered NKT (UCAR-NKT) cells by integrating iNKT TCR engineering and HLA gene editing on hematopoietic stem cells (HSCs), along with an ex vivo, feeder-free HSC differentiation culture. The UCAR-NKT cells are produced with high yield, purity, and robustness, and they display a stable HLA-ablated phenotype that enables resistance to host cell-mediated allorejection. These UCAR-NKT cells exhibit potent antitumor efficacy to blood cancers and solid tumors, both in vitro and in vivo, employing a multifaceted array of tumor-targeting mechanisms. These cells are further capable of altering the tumor microenvironment by selectively depleting immunosuppressive tumor-associated macrophages and myeloid-derived suppressor cells. In addition, UCAR-NKT cells demonstrate a favorable safety profile with low risks of graft-versus-host disease and cytokine release syndrome. Collectively, these preclinical studies underscore the feasibility and significant therapeutic potential of UCAR-NKT cell products and lay a foundation for their translational and clinical development.

A computational pipeline for identifying gene targets and signalling pathways in cancer cells to improve lymphocyte infiltration and immune checkpoint therapy efficacy

BACKGROUND

Tumour-infiltrating lymphocytes (TILs) are crucial for effective immune checkpoint blockade (ICB) therapy in solid tumours. However, ∼70% of these tumours exhibit poor lymphocyte infiltration, rendering ICB therapies less effective.

METHODS

We developed a bioinformatics pipeline integrating multiple previously unconsidered factors or datasets, including tumour cell immune-related pathways, copy number variation (CNV), and single tumour cell sequencing data, as well as tumour mRNA-seq data and patient survival data, to identify targets that can potentially improve T cell infiltration and enhance ICB efficacy. Furthermore, we conducted wet-lab experiments and successfully validated one of the top-identified genes.

FINDINGS

We applied this pipeline in solid tumours of the Cancer Genome Atlas (TCGA) and identified a set of genes in 18 cancer types that might potentially improve lymphocyte infiltration and ICB efficacy, providing a valuable drug target resource to be further explored. Importantly, we experimentally validated SUN1, which had not been linked to T cell infiltration and ICB therapy previously, but was one of the top-identified gene targets among 3 cancer types based on the pipeline, in a mouse colon cancer syngeneic model. We showed that Sun1 KO could significantly enhance antigen presentation, increase T-cell infiltration, and improve anti-PD1 treatment efficacy. Moreover, with a single-cell multiome analysis, we identified subgene regulatory networks (sub-GRNs) showing Stat proteins play important roles in enhancing the immune-related pathways in Sun1-KO cancer cells.

INTERPRETATION

This study not only established a computational pipeline for discovering new gene targets and signalling pathways in cancer cells that block T-cell infiltration, but also provided a gene target pool for further exploration in improving lymphocyte infiltration and ICB efficacy in solid tumours.

FUNDING

A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

Ketogenic Diet Alters the Epigenetic and Immune Landscape of Prostate Cancer to Overcome Resistance to Immune Checkpoint Blockade Therapy

Resistance to immune checkpoint blockade (ICB) therapy represents a formidable clinical challenge limiting the efficacy of immunotherapy. In particular, prostate cancer poses a challenge for ICB therapy due to its immunosuppressive features. A ketogenic diet (KD) has been reported to enhance response to ICB therapy in some other cancer models. However, adverse effects associated with continuous KD were also observed, demanding better mechanistic understanding and optimized regimens for using KD as an immunotherapy sensitizer. In this study, we established a series of ICB-resistant prostate cancer cell lines and developed a highly effective strategy of combining anti-PD1 and anti-CTLA4 antibodies with histone deacetylase inhibitor (HDACi) vorinostat, a cyclic KD (CKD), or dietary supplementation of the ketone body β-hydroxybutyrate (BHB), which is an endogenous HDACi. CKD and BHB supplementation each delayed prostate cancer tumor growth as monotherapy, and both BHB and adaptive immunity were required for the antitumor activity of CKD. Single-cell transcriptomic and proteomic profiling revealed that HDACi and ketogenesis enhanced ICB efficacy through both cancer cell-intrinsic mechanisms, including upregulation of MHC class I molecules, and -extrinsic mechanisms, such as CD8+ T-cell chemoattraction, M1/M2 macrophage rebalancing, monocyte differentiation toward antigen-presenting cells, and diminished neutrophil infiltration. Overall, these findings illuminate a potential clinical path of using HDACi and optimized KD regimens to enhance ICB therapy for prostate cancer.

SIGNIFICANCE

Optimized cyclic ketogenic diet and 1,3-butanediol supplementation regimens enhance the efficacy of immune checkpoint blockade in prostate cancer through epigenetic and immune modulations, providing dietary interventions to sensitize tumors to immunotherapy.

Bridging the divide: unveiling mutual immunological pathways of cancer and pregnancy

The juxtaposition of two seemingly disparate physiological phenomena within the human body-namely, cancer and pregnancy-may offer profound insights into the intricate interplay between malignancies and the immune system. Recent investigations have unveiled striking similarities between the pivotal processes underpinning fetal implantation and successful gestation and those governing tumor initiation and progression. Notably, a confluence of features has emerged, underscoring parallels between the microenvironment of tumors and the maternal-fetal interface. These shared attributes encompass establishing vascular networks, cellular mobilization, recruitment of auxiliary tissue components to facilitate continued growth, and, most significantly, the orchestration of immune-suppressive mechanisms.Our particular focus herein centers on the phenomenon of immune suppression and its protective utility in both of these contexts. In the context of pregnancy, immune suppression assumes a paramount role in shielding the semi-allogeneic fetus from the potentially hostile immune responses of the maternal host. In stark contrast, in the milieu of cancer, this very same immunological suppression fosters the transformation of the tumor microenvironment into a sanctuary personalized for the neoplastic cells.Thus, the striking parallels between the immunosuppressive strategies deployed during pregnancy and those co-opted by malignancies offer a tantalizing reservoir of insights. These insights promise to inform novel avenues in the realm of cancer immunotherapy. By harnessing our understanding of the immunological events that detrimentally impact fetal development, a knowledge grounded in the context of conditions such as preeclampsia or miscarriage, we may uncover innovative immunotherapeutic strategies to combat cancer.

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.

Immunotherapy and Radiotherapy Combinations for Sarcoma

Sarcomas are a heterogeneous group of bone and soft tissue tumors. Survival outcomes for advanced (unresectable or metastatic) disease remain poor, so therapeutic improvements are needed. Radiotherapy plays an integral role in the neoadjuvant and adjuvant treatment of localized disease as well as in the treatment of metastatic disease. Combining radiotherapy with immunotherapy to potentiate immunotherapy has been used in a variety of cancers other than sarcoma, and there is opportunity to further investigate combining immunotherapy with radiotherapy to try to improve outcomes in sarcoma. In this review, we describe the diversity of the tumor immune microenvironments for sarcomas and describe the immunomodulatory effects of radiotherapy. We discuss studies on the timing of radiotherapy relative to immunotherapy and studies on the radiotherapy dose and fractionation regimen to be used in combination with immunotherapy. We describe the impact of radiotherapy on the tumor immune microenvironment. We review completed and ongoing clinical trials combining radiotherapy with immunotherapy for sarcoma and propose future directions for studies combining immunotherapy with radiotherapy in the treatment of sarcoma.

Challenges in developing personalized neoantigen cancer vaccines

The recent success of cancer immunotherapies has highlighted the benefit of harnessing the immune system for cancer treatment. Vaccines have a long history of promoting immunity to pathogens and, consequently, vaccines targeting cancer neoantigens have been championed as a tool to direct and amplify immune responses against tumours while sparing healthy tissue. In recent years, extensive preclinical research and more than one hundred clinical trials have tested different strategies of neoantigen discovery and vaccine formulations. However, despite the enthusiasm for neoantigen vaccines, proof of unequivocal efficacy has remained beyond reach for the majority of clinical trials. In this Review, we focus on the key obstacles pertaining to vaccine design and tumour environment that remain to be overcome in order to unleash the true potential of neoantigen vaccines in cancer therapy.

NK cells propagate T cell immunity following in situ tumor vaccination

We report an in situ vaccination, adaptable to nearly any type of cancer, that combines radiotherapy targeting one tumor and intratumoral injection of this site with tumor-specific antibody and interleukin-2 (IL-2; 3xTx). In a phase I clinical trial, administration of 3xTx (with an immunocytokine fusion of tumor-specific antibody and IL-2, hu14.18-IL2) to subjects with metastatic melanoma increases peripheral CD8+ T cell effector polyfunctionality. This suggests the potential for 3xTx to promote antitumor immunity against metastatic tumors. In poorly immunogenic syngeneic murine melanoma or head and neck carcinoma models, 3xTx stimulates CD8+ T cell-mediated antitumor responses at targeted and non-targeted tumors. During 3xTx treatment, natural killer (NK) cells promote CTLA4+ regulatory T cell (Treg) apoptosis in non-targeted tumors. This is dependent on NK cell expression of CD86, which is upregulated downstream of KLRK1. NK cell depletion increases Treg infiltration, diminishing CD8+ T cell-dependent antitumor response. These findings demonstrate that NK cells sustain and propagate CD8+ T cell immunity following 3xTx.

Targeting MHC-I molecules for cancer: function, mechanism, and therapeutic prospects

The molecules of Major histocompatibility class I (MHC-I) load peptides and present them on the cell surface, which provided the immune system with the signal to detect and eliminate the infected or cancerous cells. In the context of cancer, owing to the crucial immune-regulatory roles played by MHC-I molecules, the abnormal modulation of MHC-I expression and function could be hijacked by tumor cells to escape the immune surveillance and attack, thereby promoting tumoral progression and impairing the efficacy of cancer immunotherapy. Here we reviewed and discussed the recent studies and discoveries related to the MHC-I molecules and their multidirectional functions in the development of cancer, mainly focusing on the interactions between MHC-I and the multiple participators in the tumor microenvironment and highlighting the significance of targeting MHC-I for optimizing the efficacy of cancer immunotherapy and a deeper understanding of the dynamic nature and functioning mechanism of MHC-I in cancer.

Killer instincts: natural killer cells as multifactorial cancer immunotherapy

Natural killer (NK) cells integrate heterogeneous signals for activation and inhibition using germline-encoded receptors. These receptors are stochastically co-expressed, and their concurrent engagement and signaling can adjust the sensitivity of individual cells to putative targets. Against cancers, which mutate and evolve under therapeutic and immunologic pressure, the diversity for recognition provided by NK cells may be key to comprehensive cancer control. NK cells are already being trialled as adoptive cell therapy and targets for immunotherapeutic agents. However, strategies to leverage their naturally occurring diversity and agility have not yet been developed. In this review, we discuss the receptors and signaling pathways through which signals for activation or inhibition are generated in NK cells, focusing on their roles in cancer and potential as targets for immunotherapies. Finally, we consider the impacts of receptor co-expression and the potential to engage multiple pathways of NK cell reactivity to maximize the scope and strength of antitumor activities.

Biomaterial-Mediated Genetic Reprogramming of Merkel Cell Carcinoma and Melanoma Leads to Targeted Cancer Cell Killing In Vitro and In Vivo

Tumor immunotherapy is a promising anticancer strategy; however, tumor cells may employ resistance mechanisms, including downregulation of major histocompatibility complex (MHC) molecules to avoid immune recognition. Here, we investigate reprogramming nanoparticles (NPs) that deliver immunostimulatory genes to enhance immunotherapy and address defective antigen presentation in skin cancer in vitro and in vivo. We use a modular poly(beta-amino ester) (PBAE)-based NP to deliver DNA encoding 4-1BBL, IL-12, and IFNγ to reprogram human Merkel cell carcinoma (MCC) cells in vitro and mouse melanoma tumors in vivo to drive adaptive antitumor immune responses. Optimized NP formulations delivering 4-1BBL/IL-12 or 4-1BBL/IL-12/IFNγ DNA successfully transfect MCC and melanoma cells in vitro and in vivo, respectively, resulting in IFNγ-driven upregulation of MHC class I and II molecules on cancer cells. These NPs reprogram the tumor immune microenvironment (TIME) and elicit strong T-cell-driven immune responses, leading to cancer cell killing and T-cell proliferation in vitro and slowing tumor growth and improving survival rates in vivo. Based on expected changes to the tumor immune microenvironment, particularly the importance of IFNγ to the immune response and driving both T-cell function and exhaustion, next-generation NPs codelivering IFNγ were designed. These offered mixed benefits, exchanging improved polyfunctionality for increased T-cell exhaustion and demonstrating higher systemic toxicity in vivo. Further profiling of the immune response with these NPs provides insight into T-cell exhaustion and polyfunctionality induced by different formulations, providing a greater understanding of this immunotherapeutic strategy.

Intratumoral immunotherapy with mRNAs encoding chimeric protein constructs encompassing IL-12, CD137 agonists, and TGF-β antagonists

Intratumoral immunotherapy strategies for cancer based on interleukin-12 (IL-12)-encoding cDNA and mRNA are under clinical development in combination with anti-PD-(L)1 monoclonal antibodies. To make the most of these approaches, we have constructed chimeric mRNAs encoding single-chain IL-12 fused to single-chain fragment variable (scFv) antibodies that bind to transforming growth factor β (TGF-β) and CD137 (4-1BB). Several neutralizing TGF-β agents and CD137 agonists are also undergoing early-phase clinical trials. To attain TGF-β and CD137 binding by the constructions, we used bispecific tandem scFv antibodies (taFvs) derived from the specific 1D11 and 1D8 monoclonal antibodies (mAbs), respectively. Transfection of mRNAs encoding the chimeric constructs achieved functional expression of the proteins able to act on their targets. Upon mRNA intratumoral injections in the transplantable mouse cancer models CT26, MC38, and B16OVA, potent therapeutic effects were observed following repeated injections into the tumors. Efficacy was dependent on the number of CD8+ T cells able to recognize tumor antigens that infiltrated the malignant tissue. Although the abscopal effects on concomitant uninjected lesions were modest, such distant effects on untreated lesions were markedly increased when combined with systemic PD-1 blockade.

Unleashing T cell anti-tumor immunity: new potential for 5-Nonloxytryptamine as an agent mediating MHC-I upregulation in tumors

BACKGROUND

New therapies are urgently needed in melanoma, particularly in late-stage patients not responsive to immunotherapies and kinase inhibitors. To uncover novel potentiators of T cell anti-tumor immunity, we carried out an ex vivo pharmacological screen and identified 5-Nonyloxytryptamine (5-NL), a serotonin agonist, as increasing the ability of T cells to target tumor cells.

METHODS

The pharmacological screen utilized lymphocytic choriomeningitis virus (LCMV)-primed splenic T cells and melanoma B16.F10 cells expressing the LCMV gp33 CTL epitope. In vivo tumor growth in C57BL/6 J and NSG mice, in vivo antibody depletion, flow cytometry, immunoblot, CRISPR/Cas9 knockout, histological and RNA-Seq analyses were used to decipher 5-NL's immunomodulatory effects in vitro and in vivo.

RESULTS

5-NL delayed tumor growth in vivo and the phenotype was dependent on the hosts' immune system, specifically CD8+ T cells. 5-NL's pro-immune effects were not directly consequential to T cells. Rather, 5-NL upregulated antigen presenting machinery in melanoma and other tumor cells in vitro and in vivo without increasing PD-L1 expression. Mechanistic studies indicated that 5-NL's induced MHC-I expression was inhibited by pharmacologically preventing cAMP Response Element-Binding Protein (CREB) phosphorylation. Importantly, 5-NL combined with anti-PD1 therapy showed significant improvement when compared to single anti-PD-1 treatment.

CONCLUSIONS

This study demonstrates novel therapeutic opportunities for augmenting immune responses in poorly immunogenic tumors.

Short chain fatty acids prime colorectal cancer cells to activate antitumor immunity

Introduction

Colorectal cancer (CRC) is a leading cause of death worldwide and its growth can either be promoted or inhibited by the metabolic activities of intestinal microbiota. Short chain fatty acids (SCFAs) are microbial metabolites with potent immunoregulatory properties yet there is a poor understanding of how they directly regulate immune modulating pathways within the CRC cells.

Methods

We used engineered CRC cell lines, primary organoid cultures, orthotopic in vivo models, and patient CRC samples to investigate how SCFA treatment of CRC cells regulates their ability to activate CD8+ T cells.

Results

CRC cells treated with SCFAs induced much greater activation of CD8+ T cells than untreated CRC cells. CRCs exhibiting microsatellite instability (MSI) due to inactivation of DNA mismatch repair were much more sensitive to SCFAs and induced much greater CD8+ T cell activation than chromosomally instable (CIN) CRCs with intact DNA repair, indicating a subtype-dependent response to SCFAs. This was due to SCFA-induced DNA damage that triggered upregulation of chemokine, MHCI, and antigen processing or presenting genes. This response was further potentiated by a positive feedback loop between the stimulated CRC cells and activated CD8+ T cells in the tumor microenvironment. The initiating mechanism in the CRCs was inhibition of histone deacetylation by the SCFAs that triggered genetic instability and led to an overall upregulation of genes associated with SCFA signaling and chromatin regulation. Similar gene expression patterns were found in human MSI CRC samples and in orthotopically grown MSI CRCs independent of the amount of SCFA producing bacteria in the intestine.

Discussion

MSI CRCs are widely known to be more immunogenic than CIN CRCs and have a much better prognosis. Our findings indicate that a greater sensitivity to microbially produced SCFAs contributes to the successful activation of CD8+ T cells by MSI CRCs, thereby identifying a mechanism that could be therapeutically targeted to improve antitumor immunity in CIN CRCs.

Immunogenic cell death in cancer immunotherapy

Cancer immunotherapy has been acknowledged as a new paradigm for cancer treatment, with notable therapeutic effects on certain cancer types. Despite their significant potential, clinical studies over the past decade have revealed that cancer immunotherapy has low response rates in the majority of solid tumors. One of the key causes for poor responses is known to be the relatively low immunogenicity of solid tumors. Because most solid tumors are immune desert 'cold tumors' with antitumor immunity blocked from the onset of innate immunity, combination therapies that combine validated T-based therapies with approaches that can increase tumor-immunogenicity are being considered as relevant therapeutic options. This review paper focuses on immunogenic cell death (ICD) as a way of enhancing immunogenicity in tumor tissues. We will thoroughly review how ICDs such as necroptosis, pyroptosis, and ferroptosis can improve anti-tumor immunity and outline clinical trials targeting ICD. Finally, we will discuss the potential of ICD inducers. as an adjuvant for cancer immunotherapy.[BMB Reports 2023; 56(5): 275-286].

Immunogenic cell death in cancer immunotherapy

Cancer immunotherapy has been acknowledged as a new paradigm for cancer treatment, with notable therapeutic effects on certain cancer types. Despite their significant potential, clinical studies over the past decade have revealed that cancer immunotherapy has low response rates in the majority of solid tumors. One of the key causes for poor responses is known to be the relatively low immunogenicity of solid tumors. Because most solid tumors are immune desert 'cold tumors' with antitumor immunity blocked from the onset of innate immunity, combination therapies that combine validated T-based therapies with approaches that can increase tumor-immunogenicity are being considered as relevant therapeutic options. This review paper focuses on immunogenic cell death (ICD) as a way of enhancing immunogenicity in tumor tissues. We will thoroughly review how ICDs such as necroptosis, pyroptosis, and ferroptosis can improve anti-tumor immunity and outline clinical trials targeting ICD. Finally, we will discuss the potential of ICD inducers. as an adjuvant for cancer immunotherapy.[BMB Reports 2023; 56(5): 275-286].

Preclinical and Basic Research Strategies for Overcoming Resistance to Targeted Therapies in HER2-Positive Breast Cancer

The amplification of epidermal growth factor receptor 2 (HER2) is associated with a poor prognosis and HER2 gene is overexpressed in approximately 15-30% of breast cancers. In HER2-positive breast cancer patients, HER2-targeted therapies improved clinical outcomes and survival rates. However, drug resistance to anti-HER2 drugs is almost unavoidable, leaving some patients with an unmet need for better prognoses. Therefore, exploring strategies to delay or revert drug resistance is urgent. In recent years, new targets and regimens have emerged continuously. This review discusses the fundamental mechanisms of drug resistance in the targeted therapies of HER2-positive breast cancer and summarizes recent research progress in this field, including preclinical and basic research studies.

Immunotherapy for Soft Tissue Sarcomas: Anti-PD1/PDL1 and Beyond

Sarcomas gather a heterogeneous group of mesenchymal malignant tumors including more than 150 different subtypes. Most of them represent aggressive tumors with poor prognosis at the advanced stage, despite the better molecular characterization of these tumors and the development of molecular-driven therapeutic strategies. During the last decade, immunotherapy has been developed to treat advanced cancers, mainly thanks to immune checkpoint inhibitors (ICI) such as anti-PD1/PDL1 and later to adoptive immune cell therapies. In this review, we aim to summarize the state of the art of immunotherapy in soft tissue sarcomas (STS). Overall, the clinical trials of ICI that included a wide diversity of STS subtypes reported limited efficacy with some outlying responders. Both emerging biomarkers are of interest in selecting good candidates and in the development of combination therapies. Finally, the recent breakthroughs of innovative adoptive therapies in STS seem highly promising.

HLA and tumour immunology: immune escape, immunotherapy and immune-related adverse events

PURPOSE

As molecules responsible for presenting antigens to T lymphocytes, leukocytes antigens (HLAs) play a vital role in cancer immunology. This review aims to provide current understanding of HLAs in tumour immunology.

METHODS

Perspectives on how HLA alterations may contribute to the immune escape of cancer cells and resistance to immunotherapy, and potential methods to overcome HLA defects were summarized. In addition, we discussed the potential association between HLA and immune-related adverse events (irAEs), which has not been reviewed elsewhere.

RESULTS

Downregulation, loss of heterogeneity and entire loss of HLAs are responsible for the immune escape of tumour cells. The strategies to overcome the HLA defects can be effective therapies of cancer. Compared with classical HLA-I, non-classical HLA-I molecules, such as HLA-E and HLA-G, appear to be more reliable predictors of prognosis, as they tend to play immunosuppressive roles in antitumor response. Relative diversified or high expression of classical HLA-I are potential predictors of favourable response of immunotherapy. Certain HLA types may be associated to enhanced affinity to self-antigen-mimicked tumour-antigens, thus may positively correlated to irAEs triggered by checkpoint inhibitors.

CONCLUSIONS

Further studies exploring the relationship between HLAs and cancer may not only lead to the development of novel therapies but also bring about better management of irAEs.

Exploring the landscape of immunotherapy approaches in sarcomas

Sarcomas comprise a heterogenous group of malignancies, of more than 100 different entities, arising from mesenchymal tissue, and accounting for 1% of adult malignancies. Surgery, radiotherapy and systemic therapy constitute the therapeutic armamentarium against sarcomas, with surgical excision and conventional chemotherapy, remaining the mainstay of treatment for local and advanced disease, respectively. The prognosis for patients with metastatic disease is dismal and novel therapeutic approaches are urgently required to improve survival outcomes. Immunotherapy, is a rapidly evolving field in oncology, which has been successfully applied in multiple cancers to date. Immunomodulating antibodies, adoptive cellular therapy, cancer vaccines, and cytokines have been tested in patients with different types of sarcomas through clinical trials, pilot studies, retrospective and prospective studies. The results of these studies regarding the efficacy of different types of immunotherapies in sarcomas are conflicting, and the application of immunotherapy in daily clinical practice remains limited. Additional clinical studies are ongoing in an effort to delineate the role of immunotherapy in patients with specific sarcoma subtypes.

Regulation of IFN-γ-mediated PD-L1 expression by MYC in colorectal cancer with wild-type KRAS and TP53 and its clinical implications

Introduction: In the tumor microenvironment, interferon gamma (IFN-γ) secreted by tumor infiltrating lymphocytes can upregulate programmed cell death 1 ligand 1 (PD-L1) expression in many cancers. The present study evaluated the expression of PD-L1 in selected colorectal cancer cell lines with IFN-γ treatment and explored the correlation between programmed cell death 1 ligand 1 expression and KRAS/TP53 mutation status. Methods: The selected colorectal cancer cell lines had known KRAS mutations or TP53 mutations. TCGA data analysis were used to investigate the correlation between overall survival of patient with anti-PD-1/PD-L1 immunotherapy and KRAS/TP53 mutation status. Besides, the correlation between PD-L1 expression and KRAS/TP53 mutation status were also investigated by using TCGA data analysis. In vitro experiments were used to explore the mechanism underlying KRAS- and TP53-related PD-L1 expression. Results: Firstly, TCGA data analysis for gene expression and overall survival and an in vitro study revealed that the wild-type KRAS/TP53 cell lines exhibited hyperresponsiveness to interferon gamma exposure and correlated with better survival in patients receiving anti-PD-1/PD-L1 treatment. Secondly, experimental data revealed that interferon gamma induced the upregulation of programmed cell death 1 ligand 1 mainly through regulating MYC in wild-type KRAS and TP53 colorectal cancers. Discussion: Our findings revealed that the response to anti-PD-1/PD-L1 cancer immunotherapy frequently happened in wild-type KRAS and TP53 colorectal cancers, which were also found to show higher programmed cell death 1 ligand 1 expression. Our results indicate that the wild-type KRAS/TP53 colorectal cancer cell lines may respond better to interferon gamma treatment, which causes increased programmed cell death 1 ligand 1 expression and may be a mechanism underlying the better responses to anti-PD-1/PD-L1 therapies in wild-type KRAS and wild-type TP53 colorectal cancer. Furthermore, the experimental results suggest that interferon gamma regulated programmed cell death 1 ligand 1 expression through the regulation of MYC, which may further affect the response to PD-1/PD-L1 cancer immunotherapy. These results suggest a novel potential treatment strategy for enhancing the efficacy of PD-1/PD-L1 blockade immunotherapy in most colorectal cancer patients.

Combinations of Chemotherapy and PD-1/PD-L1 Inhibitors in Sarcoma

OPINION STATEMENT

While no PD-1 inhibitor has been FDA approved for use in sarcoma or proven efficacious in a randomized trial, the use of single agent PD-1 inhibitors is standard-of-care and recommended by the NCCN guidelines in certain specific subtypes and situations. Even while the role of immunotherapy is still being defined in sarcoma, there is rising interest in combinations of PD-1 inhibitors with standard-of-care treatments, especially chemotherapy. Recently, several early phase trials have suggested potential benefits for chemotherapy in combination with PD-1 inhibitors. Although some physicians are already combining PD-1 inhibitors and chemotherapy for sarcoma off-label in the community, we believe more data is necessary. We support further evaluation of these combinations in well-designed clinical trials.

Identification of DDX60 as a Regulator of MHC-I Class Molecules in Colorectal Cancer

Immune checkpoint blockade (ICB) therapies induce durable responses in approximately 15% of colorectal cancer (CRC) patients who exhibit microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR). However, more than 80% of CRC patients do not respond to current immunotherapy. The main challenge with these patients is lack of MHC-I signaling to unmask their cancer cells so the immune cells can detect them. Here, we started by comparing IFNγ signature genes and MHC-I correlated gene lists to determine the potential candidates for MHC-I regulators. Then, the protein expression level of listed potential candidates in normal and cancer tissue was compared to select final candidates with enough disparity between the two types of tissues. ISG15 and DDX60 were further tested by wet-lab experiments. Overexpression of DDX60 upregulated the expression of MHC-I, while knockdown of DDX60 reduced the MHC-I expression in CRC cells. Moreover, DDX60 was downregulated in CRC tissues, and lower levels of DDX60 were associated with a poor prognosis. Our data showed that DDX60 could regulate MHC-I expression in CRC; thus, targeting DDX60 may improve the effects of immunotherapy in some patients.

Interferon-γ induces immunosuppression in salivary adenoid cystic carcinoma by regulating programmed death ligand 1 secretion

Interferon-γ (IFN-γ), a key effector molecule in anti-tumor immune response, has been well documented to correlate with the intratumoral infiltration of immune cells. Of interest, however, a high level of IFN-γ has been reported in salivary adenoid cystic carcinoma (SACC), which is actually a type of immunologically cold cancer with few infiltrated immune cells. Investigating the functional significance of IFN-γ in SACC would help to explain such a paradoxical phenomenon. In the present study, we revealed that, compared to oral squamous cell carcinoma cells (a type of immunologically hot cancer), SACC cells were less sensitive to the growth-inhibition effect of IFN-γ. Moreover, the migration and invasion abilities of SACC cells were obviously enhanced upon IFN-γ treatment. In addition, our results revealed that exposure to IFN-γ significantly up-regulated the level of programmed death ligand 1 (PD-L1) on SACC cell-derived small extracellular vesicles (sEVs), which subsequently induced the apoptosis of CD8⁺ T cells through antagonizing PD-1. Importantly, it was also found that SACC patients with higher levels of plasma IFN-γ also had higher levels of circulating sEVs that carried PD-L1 on their surface. Our study unveils a mechanism that IFN-γ induces immunosuppression in SACC via sEV PD-L1, which would account for the scarce immune cell infiltration and insensitivity to immunotherapy.

The Immune Contexture of Liposarcoma and Its Clinical Implications

Liposarcomas (LPS) are the most frequent malignancies in the soft tissue sarcoma family and consist of five distinctive histological subtypes, termed well-differentiated LPS, dedifferentiated LPS (DDLPS), myxoid LPS (MLPS), pleomorphic LPS, and myxoid pleomorphic LPS. They display variations in genetic alterations, clinical behavior, and prognostic course. While accumulating evidence implicates a crucial role of the tumor immune contexture in shaping the response to anticancer treatments, the immunological landscape of LPS is highly variable across different subtypes. Thus, DDLPS is characterized by a higher abundance of infiltrating T cells, yet the opposite was reported for MLPS. Interestingly, a recent study indicated that the frequency of pre-existing T cells in soft tissue sarcomas has a predictive value for immune checkpoint inhibitor (CPI) therapy. Additionally, B cells and tertiary lymphoid structures were identified as potential biomarkers for the clinical outcome of LPS patients and response to CPI therapy. Furthermore, it was demonstrated that macrophages, predominantly of M2 polarization, are frequently associated with poor prognosis. An improved understanding of the complex LPS immune contexture enables the design and refinement of novel immunotherapeutic approaches. Here, we summarize recent studies focusing on the clinicopathological, genetic, and immunological determinants of LPS.

Biomarker correlates with response to NY-ESO-1 TCR T cells in patients with synovial sarcoma

Autologous T cells transduced to express a high affinity T-cell receptor specific to NY-ESO-1 (letetresgene autoleucel, lete-cel) show promise in the treatment of metastatic synovial sarcoma, with 50% overall response rate. The efficacy of lete-cel treatment in 45 synovial sarcoma patients (NCT01343043) has been previously reported, however, biomarkers predictive of response and resistance remain to be better defined. This post-hoc analysis identifies associations of response to lete-cel with lymphodepleting chemotherapy regimen (LDR), product attributes, cell expansion, cytokines, and tumor gene expression. Responders have higher IL-15 levels pre-infusion (p = 0.011) and receive a higher number of transduced effector memory (CD45RA- CCR7-) CD8 + cells per kg (p = 0.039). Post-infusion, responders have increased IFNγ, IL-6, and peak cell expansion (p < 0.01, p < 0.01, and p = 0.016, respectively). Analysis of tumor samples post-treatment illustrates lete-cel infiltration and a decrease in expression of macrophage genes, suggesting remodeling of the tumor microenvironment. Here we report potential predictive and pharmacodynamic markers of lete-cel response that may inform LDR, cell dose, and strategies to enhance anticancer efficacy.

Biomarkers predictive of response to T cell therapy remain to be better defined. This study identifies potential predictive and pharmacodynamic markers of response to NY-ESO-1 T-cell therapy in a solid tumor that may inform lymphodepletion, cell dose, and strategies to enhance anticancer efficacy.

The Effect of the Nanoparticle Shape on T Cell Activation

The mechanism of extracellular ligand nano-geometry in ex vivo T cell activation for immunotherapy remains elusive. Herein, the authors demonstrate large aspect ratio (AR) of gold nanorods (AuNRs) conjugated on cell culture substrate enhancing both murine and human T cell activation through the nanoscale anisotropic presentation of stimulatory ligands (anti-CD3(αCD3) and anti-CD28(αCD28) antibodies). AuNRs with large AR bearing αCD3 and αCD28 antibodies significantly promote T cell expansion and key cytokine secretion including interleukin-2 (IL-2), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α). High membrane tension observed in large AR AuNRs regulates actin filament and focal adhesion assembly and develops maturation-related morphological features in T cells such as membrane ruffle formation, cell spreading, and large T cell receptor (TCR) cluster formation. Anisotropic stimulatory ligand presentation promotes differentiation of naïve CD8⁺ T cells toward the effector phenotype inducing CD137 expression upon co-culture with human cervical carcinoma. The findings suggest the importance of manipulating extracellular ligand nano-geometry in optimizing T cell behaviors to enhance therapeutic outcomes.

Immunotherapy in Sarcoma: Where Do Things Stand?

Early experiences with modern immunotherapy have been disappointing in trials of unselected sarcoma subtypes. However, remarkable efficacy has been observed with immune checkpoint inhibitors (ICIs) in a subset of patients, with the most promising outcomes to date in alveolar soft part sarcoma, cutaneous angiosarcoma, undifferentiated pleomorphic sarcoma (UPS), and dedifferentiated liposarcoma (dLPS). Adoptive cellular therapies targeting cancer testis antigens have shown promising activity, but only synovial sarcoma (SS) and myxoid/round cell liposarcomas reliably express these targets. The majority of sarcomas are immunologically "cold" with sparse immune infiltration, which may explain the poor response to immunotherapy. Current immunotherapy trials for sarcomas explore combination therapies with checkpoint inhibitors to overcome immune evasion and novel targets in adoptive cellular therapies. The role of tertiary lymphoid structures, PD-L1 expression, tumor mutational burden, microsatellite instability, and tumor lymphocytes as biomarkers for response are areas of active investigation. In this review, we highlight prior and ongoing clinical efforts to improve outcomes with immunotherapy and discuss the current state of understanding for biomarkers to select patients most likely to benefit from this approach.

The Role of Immunotherapy in the Management of Soft Tissue Sarcomas: Current Landscape and Future Outlook

Soft tissue sarcomas (STS) are a subset of sarcoma, a rare group of heterogeneous malignancies of mesenchymal origin. Current standard of care involves surgical resection with systemic chemotherapy used to treat high-risk localized and metastatic disease. Though classically thought to be immunologically quiet tumors, STS interact with the immune system, undergoing immunoediting that alters tumor immunogenicity and the tumor microenvironment. Recent advances with immune checkpoint inhibition have led to clinical trials exploring the efficacy of immunotherapy in treating STS. Results from these trials point to histologic subtype-specific clinical activity of immune checkpoint blockade. In addition, combinatorial strategies adding immune checkpoint inhibition to local or systemic therapies for STS have further increased their efficacy. Targeted immunotherapies using engineered T-cell receptor-based approaches also show increasing promise as treatment options for some patients with STS. Adoptive transfer of autologous T cells targeting NY-ESO-1 and MAGE-A4 have high response rates in sarcomas expressing these antigens, although recurrence is often seen in responding patients. Future work must focus on identifying primary and acquired mechanisms of resistance to these therapies, and extend T-cell receptor discovery to other tumor-associated antigens.

Immunotherapy of sarcomas with modified T cells

PURPOSE OF REVIEW

To summarize the development of modified T-cell therapies in sarcomas and discuss relevant published and ongoing clinical trials to date.

RECENT FINDINGS

Numerous clinical trials are underway evaluating tumor-specific chimeric antigen receptor T cells and high affinity T-cell receptor (TCR)-transduced T cells in sarcomas. Notably, translocation-dependent synovial sarcoma and myxoid/round cell liposarcoma are the subject of several phase II trials evaluating TCRs targeting cancer testis antigens New York esophageal squamous cell carcinoma-1 (NY-ESO-1) and melanoma antigen-A4 (MAGE A4), and response rates of up to 60% have been observed for NY-ESO-1 directed, modified T cells in synovial sarcoma. Challenges posed by modified T-cell therapy include limitations conferred by HLA-restriction, non-immunogenic tumor microenvironments (TME), aggressive lymphodepletion and immune-mediated toxicities restricting coinfusion of cytokines.

SUMMARY

Cellular therapy to augment the adaptive immune response through delivery of modified T cells is an area of novel therapeutic development in sarcomas where a reliably expressed, ubiquitous target antigen can be identified. Therapeutic tools to improve the specificity, signaling, proliferation and persistence of modified TCRs and augment clinical responses through safe manipulation of the sarcoma TME will be necessary to harness the full potential of this approach.

Impact of tumor microenvironment on adoptive T cell transfer activity

Recent advances in immunotherapy have revolutionized the treatment of cancer. The use of adoptive cell therapies (ACT) such as those based on tumor infiltrating lymphocytes (TILs) or genetically modified cells (transgenic TCR lymphocytes or CAR-T cells), has shown impressive results in the treatment of several types of cancers. However, cancer cells can exploit mechanisms to escape from immunosurveillance resulting in many patients not responding to these therapies or respond only transiently. The failure of immunotherapy to achieve long-term tumor control is multifactorial. On the one hand, only a limited percentage of the transferred lymphocytes is capable of circulating through the bloodstream, interacting and crossing the tumor endothelium to infiltrate the tumor. Metabolic competition, excessive glucose consumption, the high level of lactic acid secretion and the extracellular pH acidification, the shortage of essential amino acids, the hypoxic conditions or the accumulation of fatty acids in the tumor microenvironment (TME), greatly hinder the anti-tumor activity of the immune cells in ACT therapy strategies. Therefore, there is a new trend in immunotherapy research that seeks to unravel the fundamental biology that underpins the response to therapy and identifies new approaches to better amplify the efficacy of immunotherapies. In this review we address important aspects that may significantly affect the efficacy of ACT, indicating also the therapeutic alternatives that are currently being implemented to overcome these drawbacks.

Intratumoral delivery of dendritic cells plus anti-HER2 therapy triggers both robust systemic antitumor immunity and complete regression in HER2 mammary carcinoma

Background

Human epidermal growth factor receptor 2 (HER2) targeted antibodies in combination with chemotherapy has improved outcomes of HER2 positive (pos) breast cancer (BC) but toxicity of therapy remains a problem. High levels of tumor-infiltrating lymphocytes are associated with increased pathologic complete responses for patients treated with neoadjuvant therapy. Here we sought to investigate whether delivery of intratumoral (i.t.) multiepitope major histocompatibility complex (MHC) class II HER2 peptides-pulsed type I polarized dendritic cells (HER2-DC1) in combination with anti-HER2 antibodies without chemotherapy could enhance tumor regression by increasing anti-HER2 lymphocyte infiltration into the tumor.

Methods

BALB/c mice bearing orthotopic TUBO tumors, BALB/c mice bearing subcutaneous (s.c.) CT26 hHER2 tumors, or BALB-HER2/neu transgenic mice were all treated with i.t. or s.c. HER2-DC1, anti-HER2 antibodies, paclitaxel, T-DM1 or in combination. Immune response, host immune cells and effector function were analyzed using flow cytometry, interferon-γ ELISA and cytokine/chemokine arrays. The contributions of CD4⁺ and CD8⁺ T cells and antibody dependent cellular cytotoxicity (ADCC) were assessed using depleting antibodies and FcγR KO mice. Molecular changes were evaluated by immunohistochemistry and western blot.

Results

HER2-DC1 combined with anti-HER2 antibodies delivered i.t. compared to s.c. induced complete tumor regression in 75–80% of treated mice, with increased tumor infiltrating CD4⁺ and CD8⁺ T, B, natural killer T cells (NKT) and natural killer cells, and strong anti-HER2 responses in all HER2^pos BC models tested. The therapy caused regression of untreated distant tumors. Labeled HER2-DC1 migrated prominently into the distant tumor and induced infiltration of various DC subsets into tumors. HER2-DC1 i.t. combined with anti-HER2 antibodies displayed superior antitumor response compared to standard chemotherapy with anti-HER2 antibodies. Lasting immunity was attained which prevented secondary tumor formation. The presence of CD4⁺ and CD8⁺ T cells and ADCC were required for complete tumor regression. In the HER2^pos BC models, HER2-DC1 i.t. combined with anti-HER2 antibodies effectively diminished activation of HER2-mediated oncogenic signaling pathways.

Conclusions

HER2-DC1 i.t. with anti-HER2 antibodies mediates tumor regression through combined activation of T and B cell compartments and provides evidence that HER2-DC1 i.t. in combination with anti-HER2 antibodies can be tested as an effective alternative therapeutic strategy to current chemotherapy and anti-HER2 antibodies in HER2^pos BC.

Coming in from the cold: overcoming the hostile immune microenvironment of medulloblastoma

Medulloblastoma is an aggressive brain tumor that occurs predominantly in children. Despite intensive therapy, many patients die of the disease, and novel therapies are desperately needed. Although immunotherapy has shown promise in many cancers, the low mutational burden, limited infiltration of immune effector cells, and immune-suppressive microenvironment of medulloblastoma have led to the assumption that it is unlikely to respond to immunotherapy. However, emerging evidence is challenging this view. Here we review recent preclinical and clinical studies that have identified mechanisms of immune evasion in medulloblastoma, and highlight possible therapeutic interventions that may give new hope to medulloblastoma patients and their families.

Interferon-γ increases sensitivity to chemotherapy and provides immunotherapy targets in models of metastatic castration-resistant prostate cancer

Interferon-γ (IFNγ) is a cytokine with limited evidence of benefit in cancer clinical trials to date. However, it could potentially play a role in potentiating anti-tumor immunity in the immunologically "cold" metastatic castration-resistant prostate cancer (mCRPC) by inducing antigen presentation pathways and concurrently providing targets for immune checkpoint blockade therapy. Moreover, it could additionally increase sensitivity to chemotherapy based on its pleiotropic effects on cell phenotype. Here, we show that IFNγ treatment induced expression of major histocompatibility class-I (MHC-I) genes and PD-L1 in prostate cancer cells in vitro. Furthermore, IFNγ treatment led to a decrease in E-cadherin expression with a consequent increase in sensitivity to chemotherapy in vitro. In an in vivo murine tumor model of spontaneous metastatic prostate cancer, IFNγ systemic pretreatment upregulated the expression of HLA-A and decreased E-cadherin expression in the primary tumor, and more importantly in the metastatic site led to increased apoptosis and limited micrometastases in combination with paclitaxel treatment compared to diffuse metastatic disease in control and monotherapy treatment groups. These findings suggest that IFNγ may be useful in combinatorial regimens to induce sensitivity to immunotherapy and chemotherapy in hepatic metastases of mCRPC.

Post-transplant Malignancies Show Reduced T-cell Abundance and Tertiary Lymphoid Structures as Correlates of Impaired Cancer Immunosurveillance

PURPOSE

An increased risk to develop cancer is one of the most challenging negative side effects of long-term immunosuppression in organ transplant recipients and impaired cancer immunosurveillance is assumed as underlying mechanism. This study aims to elucidate transplant-related changes in the tumor immune microenvironment (TME) of cancer.

EXPERIMENTAL DESIGN

Data from 123 organ transplant recipients (kidney, heart, lung, and liver) were compared with historic data from non-immunosuppressed patients. Digital image analysis of whole-section slides was used to assess abundance and spatial distribution of T cells and tertiary lymphoid structures (TLS) in the TME of 117 tumor samples. Expression of programmed cell death 1 ligand 1 (PD-L1) and human-leucocyte-antigen class I (HLA-I) was assessed on tissue microarrays.

RESULTS

We found a remarkably reduced immune infiltrate in the center tumor (CT) regions as well as the invasive margins (IM) of post-transplant cancers. These differences were more pronounced in the IM than in the CT and larger for CD8+ T cells than for CD3+ T cells. The Immune-score integrating results from CT and IM was also lower in transplant recipients. Density of TLS was lower in cancer samples of transplant recipients. The fraction of samples with PD-L1 expression was higher in controls whereas decreased expression of HLA-I was more common in transplant recipients.

CONCLUSIONS

Our study demonstrates the impact of immunosuppression on the TME and supports impaired cancer immunosurveillance as important cause of post-transplant cancer. Modern immunosuppressive protocols and cancer therapies should consider the distinct immune microenvironment of post-transplant malignancies.

Harnessing cytokines and chemokines for cancer therapy

During the past 40 years, cytokines and cytokine receptors have been extensively investigated as either cancer targets or cancer treatments. A strong preclinical rationale supports therapeutic strategies to enhance the growth inhibitory and immunostimulatory effects of interferons and interleukins, including IL-2, IL-7, IL-12 and IL-15, or to inhibit the inflammatory and tumour-promoting actions of cytokines such as TNF, IL-1β and IL-6. This rationale is underscored by the discovery of altered and dysregulated cytokine expression in all human cancers. These findings prompted clinical trials of several cytokines or cytokine antagonists, revealing relevant biological activity but limited therapeutic efficacy. However, most trials involved patients with advanced-stage disease, which might not be the optimal setting for cytokine-based therapy. The advent of more effective immunotherapies and an increased understanding of the tumour microenvironment have presented new approaches to harnessing cytokine networks in the treatment of cancer, which include using cytokine-based therapies to enhance the activity or alleviate the immune-related toxicities of other treatments as well as to target early stage cancers. Many challenges remain, especially concerning delivery methods, context dependencies, and the pleiotropic, redundant and often conflicting actions of many cytokines. Herein, we discuss the lessons learnt from the initial trials of single-agent cytokine-based therapies and subsequent efforts to better exploit such agents for the treatment of solid tumours.

Mechanisms of immune activation and regulation: lessons from melanoma

Melanoma, a skin cancer that develops from pigment cells, has been studied intensively, particularly in terms of the immune response to tumours, and has been used as a model for the development of immunotherapy. This is due, in part, to the high mutational burden observed in melanomas, which increases both their immunogenicity and the infiltration of immune cells into the tumours, compared with other types of cancers. The immune response to melanomas involves a complex set of components and interactions. As the tumour evolves, it accumulates an increasing number of genetic and epigenetic alterations, some of which contribute to the immunogenicity of the tumour cells and the infiltration of immune cells. However, tumour evolution also enables the development of resistance mechanisms, which, in turn, lead to tumour immune escape. Understanding the interactions between melanoma tumour cells and the immune system, and the evolving changes within the melanoma tumour cells, the immune system and the microenvironment, is essential for the development of new cancer therapies. However, current research suggests that other extrinsic factors, such as the microbiome, may play a role in the immune response to melanomas. Here, we review the mechanisms underlying the immune response in the tumour and discuss recent advances as well as strategies for treatment development.

Engineering interferons and interleukins for cancer immunotherapy

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

IFN-Gamma Expression in the Tumor Microenvironment and CD8-Positive Tumor-Infiltrating Lymphocytes as Prognostic Markers in Urothelial Cancer Patients Receiving Pembrolizumab

Although immune checkpoint inhibitors have shown benefit for advanced urothelial carcinoma (aUC) patients, prognostication of treatment efficacy and response duration remains a clinical challenge. We evaluated the expression of immune markers in the tumor microenvironment and assessed their associations with response to and survival after pembrolizumab treatment in 26 aUC patients. High levels of CD8+ tumor-infiltrating lymphocytes (TILs) were associated with favorable objective responses (23.0% vs. 15.3%, p = 0.0425), progression-free survival (median, 8.8 vs 2.1 months; hazard ratio (HR), 0.24; 95% confidence interval (CI), 0.07-0.66, p = 0.0060), and overall survival (median, >24.0 vs. 5.3 months; HR, 0.17; 95% CI, 0.04-0.56, p = 0.0034) compared with low levels. High interferon-gamma (IFNγ) expression levels were associated with longer post-progression survival (median, 4.9 vs. 1.0 months; HR, 0.18; 95% CI, 0.04-0.59, p = 0.0027) compared with low expression. Multivariate analysis incorporating clinical prognosticators demonstrated that the coincidence of low CD8+ T cells/IFNγ was an independent factor for unfavorable overall survival after pembrolizumab treatment (HR, 4.07; 95% CI, 1.36-12.73; p = 0.0125). The combination of low CD8+ TILs and IFNγ expression was an independent prognostic factor with predictive ability equivalent to previously reported clinical prognosticators.