Enhancing the immune stimulatory effects of cetuximab therapy through TLR3 signalling in Epstein-Barr virus (EBV) positive nasopharyngeal carcinoma

Induction of cell death in malignant cells and regulatory T cells in the tumor microenvironment by targeting CD137

Regulatory T cells (Tregs) contribute significantly to the immunosuppressive nature of the tumor microenvironment which is a main barrier for immunotherapies of solid cancers. Reducing Treg numbers enhances anti-tumor immune responses but current depletion strategies also impair effector T cells (Teffs), potentially leading to reduced anti-tumor immunity and/or autoimmune diseases. CD137 has been identified as the most differentially expressed gene between peripheral Tregs and intratumoral Tregs in virtually all solid cancers. Further, CD137 is expressed by malignant cells of certain cancers, making it a potential target for tumor immunotherapy. Here, we report the development of a fully human anti-human CD137 antibody of the IgG1 isotype, clone P1A1, that induces antibody-dependent cell-mediated cytotoxicity (ADCC) in CD137+ Tregs and cancer cells. P1A1 cross-reacts with murine CD137 which allowed testing murine chimeric P1A1 in syngeneic murine tumor models where P1A1 significantly reduced the number of CD137+ Tregs and inhibited tumor growth in a murine hepatocellular carcinoma (HCC) and a melanoma lung metastasis model. P1A1 can also be internalized thus enabling it as a carrier for drugs to target CD137+ Tregs and cancer cells. These anti-cancer properties suggest a translation of P1A1 to human immunotherapy.

The Role of Natural Killer Cells in the Tumor Immune Microenvironment of EBV-Associated Nasopharyngeal Carcinoma

Endemic nasopharyngeal carcinoma (NPC) is closely associated with the Epstein-Barr virus (EBV), which contributes to tumor development and influences the tumor immune microenvironment (TIME) in NPC. Natural killer (NK) cells, as part of the innate immune system, play a crucial role in responding to viral infections and malignant cell transformations. Notably, NK cells possess a unique ability to target tumor cells independent of major histocompatibility complex class I (MHC I) expression. This means that MHC I-deficient tumor cells, which can escape from effective T cell attack, are susceptible to NK-cell-mediated killing. The activation of NK cells is determined by the signals generated through inhibitory and activating receptors expressed on their surface. Understanding the role of NK cells in the complex TIME of EBV+ NPC is of utmost importance. In this review, we provide a comprehensive summary of the current understanding of NK cells in NPC, focusing on their subpopulations, interactions, and cytotoxicity within the TIME. Moreover, we discuss the potential translational therapeutic applications of NK cells in NPC. This review aims to enhance our knowledge of the role of NK cells in NPC and provide valuable insights for future investigations.

Combinations of radiotherapy with immunotherapy in nasopharyngeal carcinoma

BACKGROUND

The treatment of nasopharyngeal carcinoma (NPC) is currently based on concurrent chemoradiotherapy. The prognosis of early NPC is better, while the prognosis of advanced NPC is poor. Immunotherapy is becoming increasingly commonly employed in clinical practice as a new strategy for treating malignant tumors. It has shown promising results in the treatment of certain malignant tumors, making it a current clinical research hotspot.

METHODS

This review summarizes the current immunotherapy on NPC, highlighting the application of immunotherapy and radiotherapy in the treatment of NPC.

RESULTS

X-rays can either increase or suppress anti-tumor immune responses through various pathways and mechanisms. Immune checkpoint inhibitors can usually enhance X-ray-induced anti-tumor immune responses. Detecting the immune checkpoint markers and tumor mutation markers, and the functional status of effector cells in patients can aid in the development of individualized treatment that improves the treatment efficacy with reducing drug resistance and adverse reactions. The development of a multivalent vaccine for NPC will help improve the efficacy of the vaccine. Combining techniques that increase the tumor antigens release, such as radiotherapy and oncolytic virus vaccines, may enhance the ability of the immune response.

CONCLUSIONS

To shed further light on the application of immunotherapy in NPC, large pooled studies must accumulate sufficient cases with detailed exposure data.

In situ vaccination followed by intramuscular poly-ICLC injections for the treatment of hepatocellular carcinoma in mouse models

The efficacy of treatment for advanced hepatocellular carcinoma (HCC) has remained limited. Polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) is a synthetic double-stranded RNA that serves as a viral mimic and induces an immune response. Intratumoral (IT) poly-ICLC injections can induce an autovaccination effect and prime the immune system, whereas intramuscular (IM) injection of poly-ICLC can attract and maintain tumor-specific cytotoxic T lymphocytes in tumors. We found that IT injection of poly-ICLC upregulated the expression of CD83 and CD86 on conventional type 1 dendritic cells in tumors. Combination therapy with IT followed by IM injections of poly-ICLC significantly inhibited tumor growth and increased the tumor-infiltrating CD8⁺ T cells in two syngeneic mouse models of HCC. Depletion of CD8⁺ T cells attenuated the antitumor effect. An IFN-γ enzyme-linked immunospot of purified tumoral CD8⁺ T cells revealed a significant proportion of tumor-specific T cells. Finally, the sequential poly-ICLC therapy induced abscopal effects in two dual-tumor models. This study provides evidence that the sequential poly-ICLC therapy significantly increased infiltration of tumor-specific CD8⁺ T cells in the tumors and induced CD8⁺ T cell-dependent inhibition of tumor growth, as well as abscopal effects.

Emerging role of RNA sensors in tumor microenvironment and immunotherapy

RNA sensors detect foreign and endogenous RNAs to protect the host by initiating innate and adaptive immune response. In tumor microenvironment (TME), activation of RNA sensors induces tumor-inhibitory cytotoxic T lymphocyte responses and inhibits the activity of immunosuppressive cells though stimulating type I IFN signaling pathway. These characteristics allow RNA sensors to be prospective targets in tumor immunotherapy. Therefore, a comprehensive understanding of the roles of RNA sensors in TME could provide new insight into the antitumor immunotherapy. Moreover, RNA sensors could be prominent triggering targets to synergize with immunotherapies. In this review, we highlight the diverse mechanisms of RNA sensors in cancer immunity and their emerging contributions in cancer immunotherapy, including monotherapy with RNA sensor agonists, as well as combination with chemotherapy, radiotherapy, immune checkpoint blockade or cancer vaccine.

Nasopharyngeal Carcinoma: The Role of the EGFR in Epstein-Barr Virus Infection

Epstein-Barr virus (EBV), a type 4 γ herpes virus, is recognized as a causative agent in nasopharyngeal carcinoma (NPC). Incidence of EBV-positive NPC have grown in recent decades along with worse outcomes compared with their EBV-negative counterparts. Latent membrane protein 1 (LMP1), encoded by EBV, induces NPC progression. The epidermal growth factor receptor (EGFR), a member of the ErbB family of receptor tyrosine kinases (RTK), is a driver of tumorigenesis, including for NPC. Little data exist on the relationship between EGFR and EBV-induced NPC. In our initial review, we found that LMP1 promoted the expression of EGFR in NPC in two main ways: the NF-κB pathway and STAT3 activation. On the other hand, EGFR also enhances EBV infection in NPC cells. Moreover, activation of EGFR signalling affects NPC cell proliferation, cell cycle progression, angiogenesis, invasion, and metastasis. Since EGFR promotes tumorigenesis and progression by downstream signalling pathways, causing poor outcomes in NPC patients, EGFR-targeted drugs could be considered a newly developed anti-tumor drug. Here, we summarize the major studies on EBV, EGFR, and LMP1-regulatory EGFR expression and nucleus location in NPC and discuss the clinical efficacy of EGFR-targeted agents in locally advanced NPC (LA NPC) and recurrent or metastatic NPC (R/M NPC) patients.

Integrated Analysis of the Roles of RNA Binding Proteins and Their Prognostic Value in Clear Cell Renal Cell Carcinoma

Methods

We downloaded the RNA sequencing data of ccRCC from the Cancer Genome Atlas (TCGA) database and identified differently expressed RBPs in different tissues. In this study, we used bioinformatics to analyze the expression and prognostic value of RBPs; then, we performed functional analysis and constructed a protein interaction network for them. We also screened out some RBPs related to the prognosis of ccRCC. Finally, based on the identified RBPs, we constructed a prognostic model that can predict patients' risk of illness and survival time. Also, the data in the HPA database were used for verification.

Results

In our experiment, we obtained 539 ccRCC samples and 72 normal controls. In the subsequent analysis, 87 upregulated RBPs and 38 downregulated RBPs were obtained. In addition, 9 genes related to the prognosis of patients were selected, namely, RPL36A, THOC6, RNASE2, NOVA2, TLR3, PPARGC1A, DARS, LARS2, and U2AF1L4. We further constructed a prognostic model based on these genes and plotted the ROC curve. This ROC curve performed well in judgement and evaluation. A nomogram that can judge the patient's life span is also made.

Conclusion

In conclusion, we have identified differentially expressed RBPs in ccRCC and carried out a series of in-depth research studies, the results of which may provide ideas for the diagnosis of ccRCC and the research of new targeted drugs.

The Role of NK Cells in EBV Infection and EBV-Associated NPC

A vast majority of the population worldwide are asymptomatic carriers of Epstein-Barr Virus (EBV). However, some infected individuals eventually develop EBV-related cancers, including Nasopharyngeal Carcinoma (NPC). NPC is one of the most common EBV-associated epithelial cancers, and is highly prevalent in Southern China and Southeast Asia. While NPC is highly sensitive to radiotherapy and chemotherapy, there is a lack of effective and durable treatment among the 15%–30% of patients who subsequently develop recurrent disease. Natural Killer (NK) cells are natural immune lymphocytes that are innately primed against virus-infected cells and nascent aberrant transformed cells. As EBV is found in both virally infected and cancer cells, it is of interest to examine the NK cells’ role in both EBV infection and EBV-associated NPC. Herein, we review the current understanding of how EBV-infected cells are cleared by NK cells, and how EBV can evade NK cell-mediated elimination in the context of type II latency in NPC. Next, we summarize the current literature about NPC and NK cell biology. Finally, we discuss the translational potential of NK cells in NPC. This information will deepen our understanding of host immune interactions with EBV-associated NPC and facilitate development of more effective NK-mediated therapies for NPC treatment.

Combination Treatment With Paclitaxel, Carboplatin, and Cetuximab (PCE) as First-Line Treatment in Patients With Recurrent and/or Metastatic Nasopharyngeal Carcinoma

Background: Platinum-containing doublet chemotherapy regimens are generally considered the standard first-line systemic therapy for recurrent or metastatic (R/M) nasopharyngeal cancer (NPC). Gemcitabine (GEM) plus cisplatin (CDDP) has become a standard therapy based on a phase 3 study in several countries, yet this regimen sometimes affects quality of life due to nausea or appetite loss. Here, we present the manageable toxicity and promising activity of paclitaxel + carboplatin + cetuximab (PCE) therapy for R/M NPC. Materials and Methods: We conducted a retrospective review of patients with R/M NPC who were treated with PCE from 2013 to 2019 at the National Cancer Center East, Kashiwa, Japan. PCE consisted of PTX 100 mg/m2 on days 1 and 8; CBDCA area under the blood concentration-time curve (AUC) 2.5 on days 1 and 8, repeated every 3 weeks; and cetuximab at an initial dose of 400 mg/m2, followed by 250 mg/m2 weekly, as reported in the paper. Results: Fourteen patients were identified, consisting of 10 males and 4 females with a median age 59.6 years (range, 43-74). Among the 12 of 14 patients assessed for efficacy, overall response rate was 58.3%, with 2 complete responses and 5 partial responses. On median follow-up of 23.8 months, median overall survival was not reached with observed death events of 2. Median PFS was 4.1 months (95% CI, 2.6-5.6 months). Two patients experienced disease progression during cetuximab maintenance and restarted PCE treatment, then achieved partial response again. The most common grade 3 or 4 adverse events were neutropenia (21.4%) and skin reaction (14.3%). No treatment-related death was observed. Conclusion: Although the number of study population was small, our results suggest that PCE is feasible and potentially effective for R/M NPC, with a 58.3% response rate and 4.1-month PFS. Further prospective evaluation is warranted.

Trial watch: TLR3 agonists in cancer therapy

Toll-like receptor 3 (TLR3) is a pattern recognition receptor that senses exogenous (viral) as well as endogenous (mammalian) double-stranded RNA in endosomes. On activation, TLR3 initiates a signal transduction pathway that culminates with the secretion of pro-inflammatory cytokines including type I interferon (IFN). The latter is essential not only for innate immune responses to infection but also for the initiation of antigen-specific immunity against viruses and malignant cells. These aspects of TLR3 biology have supported the development of various agonists for use as stand-alone agents or combined with other therapeutic modalities in cancer patients. Here, we review recent preclinical and clinical advances in the development of TLR3 agonists for oncological disorders.

Abbreviations

cDC, conventional dendritic cell; CMT, cytokine modulating treatment; CRC, colorectal carcinoma; CTL, cytotoxic T lymphocyte; DC, dendritic cell; dsRNA, double-stranded RNA; FLT3LG, fms-related receptor tyrosine kinase 3 ligand; HNSCC, head and neck squamous cell carcinoma; IFN, interferon; IL, interleukin; ISV, in situ vaccine; MUC1, mucin 1, cell surface associated; PD-1, programmed cell death 1; PD-L1, programmed death-ligand 1; polyA:U, polyadenylic:polyuridylic acid; polyI:C, polyriboinosinic:polyribocytidylic acid; TLR, Toll-like receptor.

Immune infiltration in nasopharyngeal carcinoma based on gene expression

Immune infiltration of nasopharyngeal carcinoma (NPC) is closely associated with the patients' prognosis. However, previous studies have not interpreted the difference of infiltrating immune cells in NPC.We comprehensively analyzed the tumor-infiltrating immune cells present in NPC for the first time, which was based on a scientific deconvolution algorithm (CIBERSORT) and the gene expression data of GSE64634. The fractions of 22 immune cells were assessed to reveal the associations between normal samples and NPC samples.Profiles of immune infiltration vary significantly between normal samples and NPC samples, and the variation could characterize the individual differences. NPC samples contained a higher proportion for M1 macrophages, whereas memory B cells and CD4 memory resting T cells were relatively lower.Our data suggest that the differences in the infiltrating immune cells in NPC and these differences would probably facilitate patient consultation and individualized treatment.