Regulation of CD137 expression through K-Ras signaling in pancreatic cancer cells

High 4-1BB Expression in PBMCs and Tumor Infiltrating Lymphocytes (TILs) in Patients with Head and Neck Squamous Cell Carcinoma

OBJECTIVE

 4-1BB is a costimulatory immune-activating molecule. Increased amounts of this protein have previously been found in the plasma of patients with oropharyngeal and oral cancer. Here, we focused on this molecule that functions as part of the immune system. We investigated 4-1BB in the peripheral blood mononuclear cells (PBMCs) and tumor infiltrating lymphocytes (TILs) of patients with head and neck squamous cell cancer (HNSCC).

MATERIALS AND METHODS

 The expression level of 4-1BB in the PBMCs was determined using real-time polymerase chain reaction (PCR). The TIMER (Tumor Immune Estimation Resource) web server was utilized to approximate the 4-1BB level in HNSCC TILs. Moreover, 4-1BB immunohistochemistry (IHC) was used to validate TILs in four organs of HNSCC, including oral cancer (OC), oropharyngeal cancer (OPC), sinonasal cancer (SNC), and laryngeal cancer (LC), in both the tumor area and adjacent normal epithelium. The difference in 4-1BB expression levels in various groups was assessed using a Kruskal-Wallis test and an independent sample t-test.

RESULTS

 The level of 4-1BB expression in PBMCs was highest in OPC, followed by OC and healthy controls (HC). Significant differences were discovered between HC and OPC and between OC and OPC. Bioinformatics revealed a substantial correlation between 4-1BB expression level and lymphocyte infiltration in HNSCC, including B cells, CD8+ T cells, and CD4+ T cells. IHC validation in HNSCC tissue revealed that the average number of 4-1BB positive TILs in all four HNSCC subtypes was considerably greater than the number of lymphocytes seen in adjacent normal tissue. Interestingly, the number of lymphocytes that were 4-1BB positive increased in relation to the TIL level.

CONCLUSION

 A higher number of 4-1BB expression levels were found in the PBMCs and TILs of HNSCC patients, implying that 4-1BB may be a promising approach for HNSCC patients to improve their immune function. It is important to study and create a treatment that uses 4-1BB medicine as well as existing drugs.

4-1BB: A promising target for cancer immunotherapy

Immunotherapy, powered by its relative efficacy and safety, has become a prominent therapeutic strategy utilized in the treatment of a wide range of diseases, including cancer. Within this class of therapeutics, there is a variety of drug types such as immune checkpoint blockade therapies, vaccines, and T cell transfer therapies that serve the purpose of harnessing the body’s immune system to combat disease. Of these different types, immune checkpoint blockades that target coinhibitory receptors, which dampen the body’s immune response, have been widely studied and established in clinic. In contrast, however, there remains room for the development and improvement of therapeutics that target costimulatory receptors and enhance the immune response against tumors, one of which being the 4-1BB (CD137/ILA/TNFRSF9) receptor. 4-1BB has been garnering attention as a promising therapeutic target in the setting of cancer, amongst other diseases, due to its broad expression profile and ability to stimulate various signaling pathways involved in the generation of a potent immune response. Since its discovery and demonstration of potential as a clinical target, major progress has been made in the knowledge of 4-1BB and the development of clinical therapeutics that target it. Thus, we seek to summarize and provide a comprehensive update and outlook on those advancements in the context of cancer and immunotherapy.

Immune-associated plasma proteins in oral and oropharyngeal cancer patients

Background

Plasma protein patterns differ between cancer patients and healthy donors. This study aimed to examine the plasma levels of several cytokines and immunological checkpoint proteins between patients with oral and oropharyngeal cancer and healthy donors.

Materials and methods

Plasma samples from healthy donors, oral cancer patients, and oropharyngeal cancer patients were analyzed using the Human Th Cytokine Panel 13-plex (IL-2, 4, 5, 6, 9, 10, 13, 17A, 17F, 21, 22, IFN-γ, and TNF-α) and Human Immune Checkpoint Panel1 12-plex [sCD25 (IL-2Ra), 4-1BB, sCD27, B7.2 (CD86), Free Active TGF-β1, CTLA-4, PD-L1, PD-L2, PD-1, Tim-3, LAG-3, and Galectin-9]. The plasma 4-1BB levels were verified by Western blot method. In addition, the study of the receive operating curve (ROC) yielded the calculation of a number of diagnostically significant indicators.

Results

Significantly increased levels of IL-6, 4-1BB, PDL-1, PD-1, and CTLA-4 and decreased levels of IL-13 and sCD27 were observed in cancer patients compared with healthy donors. These levels were highly significant, particularly for cancer patients in stage IV. Validation by Western blot revealed that cancer patients had higher plasma levels of 4-1BB than healthy donors (p < 0.05), and ROC curve analysis revealed that plasma 4-1BB had the highest cancer detection capability. Intriguingly, plasma levels of 4-1BB were significantly positively correlated with PDL-1 and PD-1 levels (p < 0.0001).

Conclusion

This data provided descriptive knowledge of oral and oropharyngeal cancer immunity at a fundamental level. Additional research should concentrate on the significantly different factors, especially 4-1BB, PDL-1, and PD-1, which may contribute to the development of novel alternative diagnostic tools or therapies for patients with oral and oropharyngeal cancer.

•

Plasma levels of 4-1BB were increased in head and neck cancer patients.

•

The level of plasma 4-1BB correlated with levels of plasma PD-1 and PDL-1.

•

Plasma 4-1BB possible to use as head and neck cancer screening.

•

Plasma 4-1BB may be developed as an alternative cancer immunotherapeutic drug.

Tumor-mediated 4-1BB induces tumor proliferation and metastasis in the colorectal cancer cells

AIMS

4-1BB is a member of the tumor necrosis factor receptor superfamily that mainly expressed on activated T-cells and plays important roles in cell proliferation and survival of T-cells and natural killer cells. The roles of 4-1BB in immune cells have been intensively studied, whereas little is known about the expression and roles of 4-1BB in cancer cells.

MAIN METHODS

In the present study, we investigated 4-1BB expression in colorectal cancer tissues from human patients and established colorectal cancer cells, using mRNA expression, FACS, and immunostaining. Cancer cell proliferation and metastasis regulated by transfected 4-1BB was evaluated by cell growth rate, colony forming assay, cell migration, and Western blot with antibodies which are involved in epithelial-mesenchymal transition and anti-apoptosis. Expression of 4-1BB was knockdown by 4-1BB shRNA to prove that 4-1BB was involved in the cell proliferation. In vivo, 4-1BB transfected cancer cells were injected into mice, to induce tumor local region or lung.

KEY FINDINGS

We found that colorectal cancer tissues from human patients and established colorectal cancer cells expressed 4-1BB at the high level. The higher expression of 4-1BB proliferated faster. In addition, we identified two forms of 4-1BB detected in colorectal cancer cells: full length form that was located on the plasma membrane and a short soluble form in the cytosol. The soluble form was also detected in the plasma from the mice with tumor xenografts expressed 4-1BB.

SIGNIFICANCE

Tumor-mediated 4-1BB expression in the colorectal cancer cells showed effects on cancer cell proliferation, invasion, and metastasis.

Mapping the single-cell landscape of acral melanoma and analysis of the molecular regulatory network of the tumor microenvironments

Acral melanoma (AM) exhibits a high incidence in Asian patients with melanoma, and it is not well treated with immunotherapy. However, little attention has been paid to the characteristics of the immune microenvironment in AM. Therefore, in this study, we collected clinical samples from Chinese patients with AM and conducted single-cell RNA sequencing to analyze the heterogeneity of its tumor microenvironments (TMEs) and the molecular regulatory network. Our analysis revealed that genes, such as TWIST1, EREG, TNFRSF9, and CTGF could drive the deregulation of various TME components. The molecular interaction relationships between TME cells, such as MIF-CD44 and TNFSF9-TNFRSF9, might be an attractive target for developing novel immunotherapeutic agents.

Acral melanoma is a type of cancer that affects the hands and feet. It tends to form on the palms, soles, and under the nails. It is rare in people of European descent, but in Asian populations it makes up more than half of all melanoma cases. Unlike other types of skin cancer, it does not respond well to immunotherapy, but scientists did not understand why.

Historically, cancer research has focused on the genetics of whole tumors. But cancer is complicated. Malignant cells recruit other cells to help them survive and grow, and to protect them from attacks by the immune system. Together, they create their own ecosystem, called the tumor microenvironment. The exact makeup of the tumor microenvironment differs depending on the type of cancer and on the genetics of the individual. Investigating the cells that ‘support’ the tumor could help to explain how acral melanoma develops and why it does not respond to treatment.

To address these questions, He et al. collected samples from six patients with acral melanoma and examined the genes used by more than 60,000 individual cells. This revealed nine different types of cells in the tumor microenvironment. Most were cancer cells, but there were also immune cells, blood vessel cells, skin cells, and a type of cell that makes connective tissue. He et al. also identified four genes that most likely shape the tumor microenvironment, and two gene pairs that may control some of the interactions between the cells.

Investigating these early findings in more detail could open new treatment avenues for acral melanoma. The number of samples in this study was small, but it provides a starting point for future investigation. With more data, researchers could start to develop treatments that target the unique tumor microenvironment of this type of cancer.

Molecular docking investigation of calotropone as a potential natural therapeutic agent against pancreatic cancer

A natural bioactive compound named calotropone has been reported as a drug candidate for several cancers, including pancreatic cancers. Herein, we used molecular docking approach to test the possible mechanisms of action of calotropone in inhibiting the growth of pancreatic cell cancer with gemcitabine as the positive control. By employing AutoDock Vina, we studied the molecular interaction between calotropone and pancreatic cancer-associated proteins, namely Glucosaminyl (N-Acetyl) Transferase 3, Glutamic-Oxaloacetic Transaminase 1, Tyrosine-protein kinase Met (c-Met), peroxisome proliferator-activated receptor γ, Budding Uninhibited by Benzimidazole 1, A Disintegrin and Metalloproteinase 10, Sex-determining region Y and Nuclear Factor kappa Beta (Nf-Kβ). Higher affinity energies of calotropone toward the aforementioned proteins (ranging from ‒7.3 to ‒9.3 kcal/mol) indicate that calotropone may work in the same manner as anticancer drug gemcitabine. Highest docking score was found at the interaction of calotropone and Nf-Kβ (‒9.3 kcal/mol).

Cisplatin and gemcitabine exert opposite effects on immunotherapy with PD-1 antibody in K-ras-driven cancer

•

Two common chemotherapeutic drugs, cisplatin and gemcitabine, exert opposite effect on the efficacy of PD-1 antibody in K-ras-driven cancers.

•

Gemcitabine antagonizes PD-1Ab due to its inhibition on T cell infiltration in tumor tissues.

•

Combination PD-1Ab and cisplatin leads to complete tumor eradication in vivo due to activation of the cGAS-mediated immune response.

•

The impact of drugs on T cell functions should be considered as a critical factor in selecting drugs for immunochemotherapy to achieve optimal therapeutic outcome.

Introduction

Immunochemotherapy using PD-1/PD-L1 antibodies in combination with chemotherapeutic agents has become a mainstream treatment for cancer patients, but it remains unclear which drug combinations would produce best therapeutic outcome.

Objectives

The purpose of this study was to investigate two common chemotherapeutic drugs, gemcitabine and cisplatin, for their impacts on the therapeutic efficacy of PD-1 antibody in K-ras-driven cancers known to overexpress PD-L1.

Methods

Both in vitro assays and syngeneic mouse tumor models were used in this study. Biochemical and molecular assays were used to determine the effects of drugs on T cell functions in cell culture models and in mouse/human tumor tissues. Allograft tumor models with K-ras mutation were used to investigate the combination effect of gemcitabine or cisplatin with immunotherapy. Data of lung cancer patients with K-ras mutation treated with cisplatin and toripalimab were analyzed to evaluate the clinical relevance of the lab findings.

Results

Cisplatin and gemcitabine unexpectedly exert opposite effect on the therapeutic activity of PD-1 antibody in vivo. Gemcitabine antagonizes the therapeutic effect of PD-1 antibody due to its significant inhibition on CD8⁺ T cell infiltration, which was observed both in mouse tumor allografts and in human pancreatic cancer tissues. In contrast, cisplatin shows synergistic activity with PD-1 antibody by activation of CD8⁺ T cells through the DNA damage-mediated cGAS-STING sensing mechanism, leading to increase of T cell infiltration and secretion of antitumor cytokines. Clinical data show that a combination of cisplatin with PD-1 antibody toripalimab could be effective in advanced lung cancer patients with K-ras mutation who failed prior therapies.

Conclusions

Our study shows that a key factor in selecting chemotherapeutic agents for immunochemotherapy is the drug’s impact on T cell functions, and that cisplatin-based chemotherapy is an excellent choice for combination with immune checkpoint antibody to achieve favorable clinical outcome.

Oncolytic Adenovirus Coding for a Variant Interleukin 2 (vIL-2) Cytokine Re-Programs the Tumor Microenvironment and Confers Enhanced Tumor Control

The notion of developing variants of the classic interleukin 2 (IL-2) cytokine has emerged from the limitations observed with the systemic use of human IL-2 in the clinic: severe adverse events accompanied by low therapeutic response rate in treated patients. Modifications made in the IL-2 receptor-binding structure leads to preferential binding of IL-2 variant cytokine to receptors on effector anti-tumor lymphocytes over T regulatory (TReg) cells. Because of their inherent immunogenicity, oncolytic adenoviruses are useful for expression of immunomodulatory molecules in tumors, for induction of a pro-inflammatory state in the tumor microenvironment. In the present study, we constructed an adenovirus coding for an IL-2 variant (vIL-2) protein, Ad5/3-E2F-d24-vIL2. Functionality of the new virus was tested in vitro, and anti-tumor efficacy and mechanism of action studies were performed in immunocompetent hamsters bearing pancreatic tumors. Ad5/3-E2F-d24-vIL2 treatment elicited efficient anti-tumor response, with 62.5% monotherapy complete response. Moreover, it promoted substantial repression of genes associated with myeloid cells mediated immunosuppression (CD11b, ARG1, CD206). This was seen in conjunction with upregulation of genes associated with tumor-infiltrating lymphocyte (TIL) cytotoxicity (CD3G, SAP, PRF1, GZMM and GZMK). In summary, Ad5/3-E2F-d24-vIL2 demonstrates therapeutic potential by counteracting immunosuppression and in efficiently coordinating lymphocytes mediated anti-tumor response in immunosuppressive tumors. Thus, Ad5/3-E2F-d24-vIL2 is a promising candidate for translation into clinical trials in human immunosuppressive solid tumors.

Depleting Tumor Cells Expressing Immune Checkpoint Ligands-A New Approach to Combat Cancer

Antibodies against inhibitory immune checkpoint molecules (ICPMs), referred to as immune checkpoint inhibitors (ICIs), have gained a prominent place in cancer therapy. Several ICIs in clinical use have been engineered to be devoid of effector functions because of the fear that ICIs with preserved effector functions could deplete immune cells, thereby curtailing antitumor immune responses. ICPM ligands (ICPMLs), however, are often overexpressed on a sizeable fraction of tumor cells of many tumor types and these tumor cells display an aggressive phenotype with changes typical of tumor cells undergoing an epithelial-mesenchymal transition. Moreover, immune cells expressing ICPMLs are often endowed with immunosuppressive or immune-deviated functionalities. Taken together, these observations suggest that compounds with the potential of depleting cells expressing ICPMLs may become useful tools for tumor therapy. In this article, we summarize the current state of the art of these compounds, including avelumab, which is the only ICI targeting an ICPML with preserved effector functions that has gained approval so far. We also discuss approaches allowing to obtain compounds with enhanced tumor cell-depleting potential compared to native antibodies. Eventually, we propose treatment protocols that may be applied in order to optimize the therapeutic efficacy of compounds that deplete cells expressing ICPMLs.

Role of ADAM10 and ADAM17 in Regulating CD137 Function

Human CD137 (4-1BB), a member of the TNF receptor family, and its ligand CD137L (4-1BBL), are expressed on immune cells and tumor cells. CD137/CD137L interaction mediates bidirectional cellular responses of potential relevance in inflammatory diseases, autoimmunity and oncology. A soluble form of CD137 exists, elevated levels of which have been reported in patients with rheumatoid arthritis and various malignancies. Soluble CD137 (sCD137) is considered to represent a splice variant of CD137. In this report, however, evidence is presented that A Disintegrin and Metalloproteinase (ADAM)10 and potentially also ADAM17 are centrally involved in its generation. Release of sCD137 by transfected cell lines and primary T cells was uniformly inhibitable by ADAM10 inhibition. The shedding function of ADAM10 can be blocked through inhibition of its interaction with surface exposed phosphatidylserine (PS), and this effectively inhibited sCD137 generation. The phospholipid scramblase Anoctamin-6 (ANO6) traffics PS to the outer membrane and thus modifies ADAM10 function. Overexpression of ANO6 increased stimulated shedding, and hyperactive ANO6 led to maximal constitutive shedding of CD137. sCD137 was functionally active and augmented T cell proliferation. Our findings shed new light on the regulation of CD137/CD137L immune responses with potential impact on immunotherapeutic approaches targeting CD137.

An overview of genetic mutations and epigenetic signatures in the course of pancreatic cancer progression

Pancreatic cancer (PC) is assumed to be an intimidating and deadly malignancy due to being the leading cause of cancer-led mortality, predominantly affecting males of older age. The overall (5 years) survival rate of PC is less than 9% and is anticipated to be aggravated in the future due to the lack of molecular acquaintance and diagnostic tools for its early detection. Multiple factors are involved in the course of PC development, including genetics, cigarette smoking, alcohol, family history, and aberrant epigenetic signatures of the epigenome. In this review, we will mainly focus on the genetic mutations and epigenetic signature of PC. Multiple tumor suppressor and oncogene mutations are involved in PC initiation, including K-RAS, p53, CDKN2A, and SMAD4. The mutational frequency of these genes ranges from 50 to 98% in PC. The nature of mutation diagnosis is mostly homozygous deletion, point mutation, and aberrant methylation. In addition to genetic modification, epigenetic alterations particularly aberrant hypermethylation and hypomethylation also predispose patients to PC. Hypermethylation is mostly involved in the downregulation of tumor suppressor genes and leads to PC, while multiple genes also represent a hypomethylation status in PC. Several renewable drugs and detection tools have been developed to cope with this aggressive malady, but all are futile, and surgical resection remains the only choice for prolonged survival if diagnosed before metastasis. However, the available therapeutic development is insufficient to cure PC. Therefore, novel approaches are a prerequisite to elucidating the genetic and epigenetic mechanisms underlying PC progression for healthier lifelong survival.

Ectopic CD137 expression by rhabdomyosarcoma provides selection advantages but allows immunotherapeutic targeting

Rhabdomyosarcoma (RMS) is a heterogeneous soft tissue neoplasm most frequently found in children and adolescents. As the prognosis for recurrent and metastatic RMS remains poor, immunotherapies are hoped to improve quality of life and survival. CD137 is a member of tumor necrosis factor receptor family and a T cell costimulatory molecule which induces potent cellular immune responses that are able to eliminate malignant cells. Therefore, it was puzzling to find expression of CD137 on an RMS tissue microarray by multiplex staining. CD137 is not only expressed by infiltrating T cells but also by malignant RMS cells. Functional in vitro experiments demonstrate that CD137 on RMS cells is being transferred to adjacent antigen-presenting cells by trogocytosis, where it downregulates CD137 ligand, and thereby reduces T cell costimulation which results in reduced killing of RMS cells. The transfer of CD137 and the subsequent downregulation of CD137 ligand is a physiological negative feedback mechanism that is likely usurped by RMS, and may facilitate its escape from immune surveillance. In addition, CD137 signals into RMS cells and induces IL-6 and IL-8 secretion, which are linked to RMS metastasis and poor prognosis. However, the ectopic expression of CD137 on RMS cells is an Achilles’ heel that may be utilized for immunotherapy. Natural killer cells expressing an anti-CD137 chimeric antigen receptor specifically kill CD137-expressing RMS cells. Our study implicates ectopic CD137 expression as a pathogenesis mechanism in RMS, and it demonstrates that CD137 may be a novel target for immunotherapy of RMS.

Mechanisms of T-Cell Exhaustion in Pancreatic Cancer

T-cell exhaustion is a phenomenon that represents the dysfunctional state of T cells in chronic infections and cancer and is closely associated with poor prognosis in many cancers. The endogenous T-cell immunity and genetically edited cell therapies (CAR-T) failed to prevent tumor immune evasion. The effector T-cell activity is perturbed by an imbalance between inhibitory and stimulatory signals causing a reprogramming in metabolism and the high levels of multiple inhibitory receptors like programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), and Lymphocyte-activation gene 3 (Lag-3). Despite the efforts to neutralize inhibitory receptors by a single agent or combinatorial immune checkpoint inhibitors to boost effector function, PDAC remains unresponsive to these therapies, suggesting that multiple molecular mechanisms play a role in stimulating the exhaustion state of tumor-infiltrating T cells. Recent studies utilizing transcriptomics, mass cytometry, and epigenomics revealed a critical role of Thymocyte selection-associated high mobility group box protein (TOX) genes and TOX-associated pathways, driving T-cell exhaustion in chronic infection and cancer. Here, we will review recently defined molecular, genetic, and cellular factors that drive T-cell exhaustion in PDAC. We will also discuss the effects of available immune checkpoint inhibitors and the latest clinical trials targeting various molecular factors mediating T-cell exhaustion in PDAC.