Therapeutic Immune Modulation against Solid Cancers with Intratumoral Poly-ICLC: A Pilot Trial

Poly(α-l-lysine)-based nanomaterials for versatile biomedical applications: Current advances and perspectives

Poly(α-l-lysine) (PLL) is a class of water-soluble, cationic biopolymer composed of α-l-lysine structural units. The previous decade witnessed tremendous progress in the synthesis and biomedical applications of PLL and its composites. PLL-based polymers and copolymers, till date, have been extensively explored in the contexts such as antibacterial agents, gene/drug/protein delivery systems, bio-sensing, bio-imaging, and tissue engineering. This review aims to summarize the recent advances in PLL-based nanomaterials in these biomedical fields over the last decade. The review first describes the synthesis of PLL and its derivatives, followed by the main text of their recent biomedical applications and translational studies. Finally, the challenges and perspectives of PLL-based nanomaterials in biomedical fields are addressed.

Hyalase-Mediated Cascade Degradation of a Matrix Barrier and Immune Cell Penetration by a Photothermal Microneedle for Efficient Anticancer Therapy

For melanoma with high lethality and metastasis rate, traditional therapy has limited effects; local photothermal therapy (PTT) synergetic with immune therapy for cancer treatment can perhaps improve the situation. However, because of the natural existence of the tumor matrix barrier, the penetration depth of drugs and immune cells often dampens the efficacy of cancer treatment. Herein, we report an innovative synergetic PTT and immune therapy through dissolving microneedles for the codelivery of the hyaluronidase-modified semiconductor polymer nanoparticles containing poly(cyclopentadithiophene-alt-benzothiadiazole) and immune adjuvant polyinosinic-polycytidylic acid (PIC). Benefiting from the dissolution of an extracellular matrix of hyaluronidase, the semiconductor polymer nanoparticles and PIC penetrate the tumor deeply, under synergetic therapy with PTT, activating the immune cells and enhancing the T-cell immune response for inhibition of tumor growth and metastasis. This study provides a promising platform for effective melanoma treatment and a novel strategy to overcome the stromal barrier.

Turning enemies into allies-reprogramming tumor-associated macrophages for cancer therapy

Checkpoint blockade therapies that target inhibitory receptors on T cells have revolutionized clinical oncology. Antibodies targeting CTLA-4 or the PD-1/PD-L1 axis are now successfully used alone or in combination with chemotherapy for numerous tumor types. Despite the clinical success of checkpoint blockade therapies, tumors exploit multiple mechanisms to escape or subvert the anti-tumor T cell response. Within the tumor microenvironment, tumor-associated macrophages (TAM) can suppress T cell responses and facilitate tumor growth in various ways, ultimately debilitating clinical responses to T cell checkpoint inhibitors. There is therefore significant interest in identifying biologicals and drugs that target immunosuppressive TAM within the tumor microenvironment and can be combined with immune checkpoint inhibitors. Here we review approaches that are currently being evaluated to convert immunosuppressive TAM into immunostimulatory macrophages that promote T cell responses and tumor elimination. Tumor-associated macrophages (TAMs) are a major component of the tumor microenvironment that impact anti-tumor immune responses and susceptibility to checkpoint blockade. TAMs are very heterogeneous and can be either immunosuppressive or immunostimulatory. Here, Molgora and Colonna review current strategies that aim to reprogram TAMs to enhance rather than inhibit immune responses.

Current status of intralesional agents in treatment of malignant melanoma

Prognosis of metastatic melanoma has undergone substantial improvement with the discovery of checkpoint inhibitors. Immunotherapies and targeted therapies have improved the median overall survival (OS) of metastatic melanoma from 6 months to more than 3 years. However, still about half of the patients die due to uncontrolled disease. Therefore, multiple strategies are currently being investigated to improve outcomes. One such strategy is intralesional/intratumoral (IT) therapies which can either directly kill the tumor cells or make the tumor more immunogenic to be recognized by the immune system. Talimogene laherparepvec (T-VEC), an oncolytic virus, is the first FDA approved IT therapy. This review focuses on the current status of IT agents currently under clinical trials in melanoma. Reviewed therapies include T-VEC, T-VEC with immune checkpoint inhibitors including ipilimumab and pembrolizumab or other agents, RP1, OrienX010, Canerpaturev (C-REV, HF10), CAVATAK (coxsackievirus A21, CVA21) alone or in combination with checkpoint inhibitors, oncolytic polio/rhinovirus recombinant (PVSRIPO), MAGE-A3-expressing MG1 Maraba virus, VSV-IFNbetaTYRP1, suicide gene therapy, ONCOS-102, OBP-301 (Telomelysin), Stimulation of Interferon Genes Pathway (STING agonists) including DMXAA, MIW815 (ADU-S100) and MK-1454, PV-10, toll-like receptors (TLRs) agonists including TLR-9 agonists (SD-101, CMP-001, IMO-2125 or tilsotolimod, AST-008 or cavrotolimod, MGN1703 or lefitolimod), CV8102, NKTR-262 plus NKTR-214, LHC165, G100, intralesional interleukin-2, Daromun (L19IL2 plus L19TNF), Hiltonol (poly-ICLC), electroporation including calcium electroporation and plasmid interleukin-12 electroporation (pIL-12 EP), IT ipilimumab, INT230-6 (cisplatin and vinblastine with an amphiphilic penetration enhancer), TTI-621 (SIRPαFc), CD-40 agonistic antibodies (ABBV-927 and APX005M), antimicrobial peptide LL37 and other miscellaneous agents.

Systemic immunity in cancer

Immunotherapy has revolutionized cancer treatment, but efficacy remains limited in most clinical settings. Cancer is a systemic disease that induces many functional and compositional changes to the immune system as a whole. Immunity is regulated by interactions of diverse cell lineages across tissues. Therefore, an improved understanding of tumour immunology must assess the systemic immune landscape beyond the tumour microenvironment (TME). Importantly, the peripheral immune system is required to drive effective natural and therapeutically induced antitumour immune responses. In fact, emerging evidence suggests that immunotherapy drives new immune responses rather than the reinvigoration of pre-existing immune responses. However, new immune responses in individuals burdened with tumours are compromised even beyond the TME. Herein, we aim to comprehensively outline the current knowledge of systemic immunity in cancer.

Therapeutic cancer vaccines

Therapeutic cancer vaccines have undergone a resurgence in the past decade. A better understanding of the breadth of tumour-associated antigens, the native immune response and development of novel technologies for antigen delivery has facilitated improved vaccine design. The goal of therapeutic cancer vaccines is to induce tumour regression, eradicate minimal residual disease, establish lasting antitumour memory and avoid non-specific or adverse reactions. However, tumour-induced immunosuppression and immunoresistance pose significant challenges to achieving this goal. In this Review, we deliberate on how to improve and expand the antigen repertoire for vaccines, consider developments in vaccine platforms and explore antigen-agnostic in situ vaccines. Furthermore, we summarize the reasons for failure of cancer vaccines in the past and provide an overview of various mechanisms of resistance posed by the tumour. Finally, we propose strategies for combining suitable vaccine platforms with novel immunomodulatory approaches and standard-of-care treatments for overcoming tumour resistance and enhancing clinical efficacy.

Intratumoral (Poly-ICLC) Therapy for Dogs with Advanced Cancers: First Report on Clinical Effectiveness, Quality of Life, and Adverse Events

Polyinosinic-polycytidylic acid-poly-l-lysine carboxymethylcellulose (poly-ICLC) is a synthetic double-stranded viral RNA analog widely tested as a component of human therapeutic cancer vaccines and as a standalone agent for treating human cancers. However, there are no reports on the use of poly-ICLC for treating canine cancers. This study aimed to investigate the clinical efficacy, quality of life (QL), and adverse events of poly-ICLC treatment in dogs with advanced cancers. The treatment protocol consisted of weekly intratumoral doses of poly-ICLC. The canine patients underwent clinical, laboratory, and imaging tests, and their owners answered weekly QL questionnaires. Fourteen canine patients with different types of spontaneous advanced tumors were enrolled. Most dogs had received prior conventional therapies. Five dogs received at least 12 doses of poly-ICLC: the injected tumor was stable in three dogs, there was a partial response in one, and the injected tumor significantly enlarged in the other. The QL scoring remained stable or increased in most cases. Mild adverse events related to poly-ICLC were observed in 10 of the 14 patients. The data showed that intratumoral poly-ICLC therapy was well tolerated in dogs with advanced cancers, with clinical benefit and improved QL scores observed in some dogs.

Towards customized cancer vaccines: a promising filed in personalized cancer medicine

INTRODUCTION

Cancer remains a major source of disease burden worldwide. Although cancer vaccines have been developed, most currently available cancer vaccines have limited therapeutic efficacy. Recent research using novel sequencing and bioinformatic tools has led scientists to realize that each tumor harbors a unique set of genetic mutations that can manifest as tumor-specific neoantigens. Therefore, it would be useful to develop personalized cancer vaccines that target neoantigens, which might improve the efficacy of these cancer treatments.

AREAS COVERED

This review covers cancer vaccine development and the emerging field of personalized cancer vaccines, with a discussion of future clinical trials for this promising treatment strategy.

EXPERT OPINION

Developing vaccines to treat tumors is one of the most promising and exciting fields in cancer research. However, cancer vaccines have shown limited efficacy in clinical trials for several decades, which may be related to the unique and complex processes underlying tumor development and progression. Recent studies have indicated that tumors express highly specific neoantigens, which are distinct from self-antigens. Thus, developing cancer vaccines that target these tumor-specific neoantigens is a promising strategy for developing personalized cancer vaccines.

Nucleic Acid Sensors as Therapeutic Targets for Human Disease

Innate immune sensors that detect nucleic acids are attractive targets for therapeutic intervention because of their diverse roles in many disease processes. In detecting RNA and DNA from either self or non-self, nucleic acid sensors mediate the pathogenesis of many autoimmune and inflammatory conditions. Despite promising pre-clinical data and investigational use in the clinic, relatively few drugs targeting nucleic acid sensors are approved for therapeutic use. Nevertheless, there is growing appreciation for the untapped potential of nucleic acid sensors as therapeutic targets, driven by the need for better therapies for cancer, infectious diseases, and autoimmune disorders. This review highlights the diverse mechanisms by which nucleic acid sensors are activated and exert their biological effects in the context of various disease settings. We discuss current therapeutic strategies utilizing agonists and antagonists targeting nucleic acid sensors to treat infectious disease, cancer, and autoimmune and inflammatory disorders.

Monocyte-macrophage polarization and recruitment pathways in the tumour microenvironment of B-cell acute lymphoblastic leukaemia

B-cell acute lymphoblastic leukaemia (B-ALL) reprograms the surrounding bone marrow (BM) stroma to create a leukaemia-supportive niche. To elucidate the contribution of immune cells to the leukaemic microenvironment, we investigated the involvement of monocyte/macrophage compartments, as well as several recruitment pathways in B-ALL development. Immunohistochemistry analyses showed that CD68-expressing macrophages were increased in leukaemic BM biopsies, compared to controls and predominantly expressed the M2-like markers CD163 and CD206. Furthermore, the "non-classical" CD14⁺ CD16⁺⁺ monocyte subset, expressing high CX3CR1 levels, was significantly increased in B-ALL patients' peripheral blood. CX3CL1 was shown to be significantly upregulated in leukaemic BM plasma, thus providing an altered migratory pathway possibly guiding NC monocyte recruitment into the BM. Additionally, the monocyte/macrophage chemoattractant chemokine ligand 2 (CCL2) strongly increased in leukaemic BM plasma, possibly because of the interaction of leukaemic cells with mesenchymal stromal cells and vascular cells and due to a stimulatory effect of leukaemia-related inflammatory mediators. C5a, a macrophage chemoattractant and M2-polarizing factor, further appeared to be upregulated in the leukaemic BM, possibly as an effect of PTX3 decrease, that could unleash complement cascade activation. Overall, deregulated monocyte/macrophage compartments are part of the extensive BM microenvironment remodelling at B-ALL diagnosis and could represent valuable targets for novel treatments to be coupled with classical chemotherapy.

Targeting Innate Immunity in Cancer Therapy

The majority of current cancer immunotherapy strategies target and potentiate antitumor adaptive immune responses. Unfortunately, the efficacy of these treatments has been limited to a fraction of patients within a subset of tumor types, with an aggregate response rate of approximately 20% to date across all malignancies. The success of therapeutic inhibition of programmed death protein 1 (PD-1), protein death ligand 1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) with immune checkpoint inhibitors (ICI) has been limited to “hot” tumors characterized by preexisting T cell infiltration, whereas “cold” tumors, which lack T cell infiltration, have not achieved durable benefit. There are several mechanisms by which “cold” tumors fail to generate spontaneous immune infiltration, which converge upon the generation of an immunosuppressive tumor microenvironment (TME). The role of the innate immune system in tumor immunosurveillance and generation of antitumor immune responses has been long recognized. In recent years, novel strategies to target innate immunity in cancer therapy have emerged, including therapeutic stimulation of pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs); the DNA sensing cGAS/STING pathway; nucleotide-binding oligomerization domain-like receptors (NLRs), such as NLRP3; and the retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs). In addition, therapeutic modulation of key innate immune cell types, such as macrophages and natural killer cells, has been investigated. Herein, we review therapeutic approaches to activate innate immunity within the TME to enhance antitumor immune responses, with the goal of disease eradication in “cold” tumors. In addition, we discuss rational immune-oncology combination strategies that activate both innate and adaptive immunity, with the potential to enhance the efficacy of current immunotherapeutic approaches.

Therapeutic Manipulation of Tumor-associated Macrophages: Facts and Hopes from a Clinical and Translational Perspective

The stroma of most solid tumors is populated by myeloid cells, which mostly represent macrophages. Tumor-associated macrophages (TAMs), strongly influenced by cancer cell-derived factors, are key drivers of immunosuppression and support tumor growth and spread to distant sites. Their accurate quantification and characterization in the tumor microenvironment are gaining prognostic value: increasing evidence demonstrates their ability to hamper cancer patients' response to chemotherapy, as well as to immunotherapies based on checkpoint inhibition. Therefore, strategies to counteract their negative effects are nowadays gaining momentum at preclinical, translational, and clinical levels. Our knowledge of the biology of TAMs has greatly advanced in the last years; several strategies to target and reprogram their functions to become antitumor effectors have proven successful in experimental preclinical tumor models; on the other hand, few approaches have so far been effectively translated into clinic practice. A growing interest in the therapeutic manipulation of TAMs is evidenced by numerous early-phase clinical trials, which are continuously fueled by new discoveries from basic research. This gives us hope that the targeting and sustained reprogramming of TAMs will be more specific to synergize with current therapies and maximize antitumor responses in patients.

The role of dendritic cells in tumor microenvironments and their uses as therapeutic targets

Dendritic cells (DC), which consist of several different subsets, specialize in antigen presentation and are critical for mediating the innate and adaptive immune responses. DC subsets can be classified into conventional, plasmacytoid, and monocyte-derived DC in the tumor microenvironment, and each subset plays a different role. Because of the role of intratumoral DCs in initiating antitumor immune responses with tumor-derived antigen presentation to T cells, DCs have been targeted in the treatment of cancer. By regulating the functionality of DCs, several DC-based immunotherapies have been developed, including administration of tumor-derived antigens and DC vaccines. In addition, DCs participate in the mechanisms of classical cancer therapies, such as radiation therapy and chemotherapy. Thus, regulating DCs is also important in improving current cancer therapies. Here, we will discuss the role of each DC subset in antitumor immune responses, and the current status of DC-related cancer therapies.

Double-Stranded RNA Immunomodulators in Prostate Cancer

Relatively simple, synthetic, double-stranded RNAs can be powerful viral pathogen-associated molecular pattern (PAMP) mimics, inducing a panoply of antiviral and antitumor responses that act at multiple stages of host defense. Their mechanisms of action and uses are beginning to be understood, alone, in combination with other therapeutics, or as novel PAMP-adjuvants providing the critical danger signal that has been missing from most cancer and other modern vaccines. Dose, timing, route of administration combinations, and other clinical variables can have a critical impact on immunogenicity. This article reviews advances in the use of polyinosinic-polycytidylic acid and derivatives, in particular poly-ICLC.

Immunobiology and immunotherapy of HCC: spotlight on innate and innate-like immune cells

Immune-based therapies such as immune checkpoint inhibitors have revolutionized the systemic treatment of various cancer types. The therapeutic application of monoclonal antibodies targeting inhibitory pathways such as programmed cell death-1(PD-1)/programmed cell death ligand 1 (PD-L1) and CTLA-4 to cells of the adaptive immune system has recently been shown to generate meaningful improvement in the clinical outcome of hepatocellular carcinoma (HCC). Nevertheless, current immunotherapeutic approaches induce durable responses in only a subset of HCC patients. Since immunologic mechanisms such as chronic inflammation due to chronic viral hepatitis or alcoholic and nonalcoholic fatty liver disease play a crucial role in the initiation, development, and progression of HCC, it is important to understand the underlying mechanisms shaping the unique tumor microenvironment of liver cancer. The liver is an immunologic organ with large populations of innate and innate-like immune cells and is exposed to bacterial, viral, and fungal antigens through the gut-liver axis. Here, we summarize and highlight the role of these cells in liver cancer and propose strategies to therapeutically target them. We also discuss current immunotherapeutic strategies in HCC and outline recent advances in our understanding of how the therapeutic potential of these agents might be enhanced.

Polymeric nanoparticles for RNA delivery

As exemplified by recent clinical approval of RNA drugs including the latest COVID-19 mRNA vaccines, RNA therapy has demonstrated great promise as an emerging medicine. Central to the success of RNA therapy is the delivery of RNA molecules into the right cells at the right location. While the clinical success of nanotechnology in RNA therapy has been limited to lipid-based nanoparticles currently, polymers, due to their tunability and robustness, have also evolved as a class of promising material for the delivery of various therapeutics including RNAs. This article overviews different types of polymers used in RNA delivery and the methods for the formulation of polymeric nanoparticles and highlights recent progress of polymeric nanoparticle-based RNA therapy.

Unexplored horizons of cDC1 in immunity and tolerance

Dendritic cells are a specialized subset of hematopoietic cells essential for mounting immunity against tumors and infectious disease as well as inducing tolerance for maintenance of homeostasis. DCs are equipped with number of immunoregulatory or stimulatory molecules that interact with other leukocytes to modulate their functions. Recent advances in DC biology identified a specific role for the conventional dendritic cell type 1 (cDC1) in eliciting cytotoxic CD8+ T cells essential for clearance of tumors and infected cells. The critical role of this subset in eliciting immune responses or inducing tolerance has largely been defined in mice whereas the biology of human cDC1 is poorly characterized owing to their extremely low frequency in tissues. A detailed characterization of the functions of many immunoregulatory and stimulatory molecules expressed by human cDC1 is critical for understanding their biology to exploit this subset for designing novel therapeutic modalities against cancer, infectious disease and autoimmune disorders.

New horizons in adjuvants for vaccine development

Adjuvant molecules, particularly toll like receptor (TLR) agonists have been in development for decades, though until now only a natural TLR 4 ligand (mono-phosphoryl lipid A, MPL) has been incorporated into licensed vaccine products, in formulations than enhance and complement the MPL activity. The inclusion of MPL-based formulations into vaccines has been based on enhancing antibody responses to subunit antigens, and has provided important proof-of-concept for enhancing desired immune responses to defined molecular targets. Challenges remain in adjuvant development, particularly for those that stimulated effective T cell responses for both preventative and therapeutic vaccines. The discovery of molecules, many based on RNA, that stimulate innate and adaptive immune responses and have the ability to stimulate potent CD8 T cell responses, has opened the door for development of a new generation of vaccines.

Poly-ICLC, a multi-functional immune modulator for treating cancer

Immunotherapies have become the first line of treatment for many cancer types. Unfortunately, only a small fraction of patients benefits from these therapies. This low rate of success can be attributed to 3 main barriers: 1) low frequency of anti-tumor specific T cells; 2) lack of infiltration of the anti-tumor specific T cells into the tumor parenchyma and 3) accumulation of highly suppressive cells in the tumor mass that inhibit the effector function of the anti-tumor specific T cells. Thus, the identification of immunomodulators that can increase the frequency and/or the infiltration of antitumor specific T cells while reducing the suppressive capacity of the tumor microenvironment is necessary to ensure the effectiveness of T cell immunotherapies. In this review, we discuss the potential of poly-ICLC as a multi-functional immune modulator for treating cancer and its impact on the 3 above mentioned barriers. We describe the unique capacity of poly-ICLC in stimulating 2 separate pattern recognition receptors, TLR3 and cytosolic MDA5 and the consequences of these activations on cytokines and chemokines production. We emphasize the role of poly-ICLC as an adjuvant in the setting of peptide-based cancer vaccines and in situ tumor vaccination by mimicking natural immune responses to infections. Finally, we summarize the impact of poly-ICLC in enhancing T infiltration into the tumor parenchyma and address the implication of this finding in the clinic.

Chemical Strategies to Boost Cancer Vaccines

Personalized cancer vaccines (PCVs) are reinvigorating vaccine strategies in cancer immunotherapy. In contrast to adoptive T-cell therapy and checkpoint blockade, the PCV strategy modulates the innate and adaptive immune systems with broader activation to redeploy antitumor immunity with individualized tumor-specific antigens (neoantigens). Following a sequential scheme of tumor biopsy, mutation analysis, and epitope prediction, the administration of neoantigens with synthetic long peptide (SLP) or mRNA formulations dramatically improves the population and activity of antigen-specific CD4+ and CD8+ T cells. Despite the promising prospect of PCVs, there is still great potential for optimizing prevaccination procedures and vaccine potency. In particular, the arduous development of tumor-associated antigen (TAA)-based vaccines provides valuable experience and rational principles for augmenting vaccine potency which is expected to advance PCV through the design of adjuvants, delivery systems, and immunosuppressive tumor microenvironment (TME) reversion since current personalized vaccination simply admixes antigens with adjuvants. Considering the broader application of TAA-based vaccine design, these two strategies complement each other and can lead to both personalized and universal therapeutic methods. Chemical strategies provide vast opportunities for (1) exploring novel adjuvants, including synthetic molecules and materials with optimizable activity, (2) constructing efficient and precise delivery systems to avoid systemic diffusion, improve biosafety, target secondary lymphoid organs, and enhance antigen presentation, and (3) combining bioengineering methods to innovate improvements in conventional vaccination, "smartly" re-educate the TME, and modulate antitumor immunity. As chemical strategies have proven versatility, reliability, and universality in the design of T cell- and B cell-based antitumor vaccines, the union of such numerous chemical methods in vaccine construction is expected to provide new vigor and vitality in cancer treatment.

Poly-IC enhances the effectiveness of cancer immunotherapy by promoting T cell tumor infiltration

BACKGROUND

Immunotherapies, such as immune checkpoint inhibitors and adoptive cell therapies, have revolutionized cancer treatment and resulted in complete and durable responses in some patients. Unfortunately, most immunotherapy treated patients still fail to respond. Absence of T cell infiltration to the tumor site is one of the major obstacles limiting immunotherapy efficacy against solid tumors. Thus, the development of strategies that enhance T cell infiltration and broaden the antitumor efficacy of immunotherapies is greatly needed.

METHODS

We used mouse tumor models, genetically deficient mice and vascular endothelial cells (VECs) to study the requirements for T cell infiltration into tumors.

RESULTS

A specific formulation of poly-IC, containing poly-lysine and carboxymethylcellulose (PICLC) facilitated the traffic and infiltration of effector CD8 T cells into the tumors that reduced tumor growth. Surprisingly, intratumoral injection of PICLC was significantly less effective in inducing tumor T cell infiltration and controlling growth of tumors as compared with systemic (intravenous or intramuscular) administration. Systemically administered PICLC, but not poly-IC stimulated tumor VECs via the double-stranded RNA cytoplasmic sensor MDA5, resulting in enhanced adhesion molecule expression and the production of type I interferon (IFN-I) and T cell recruiting chemokines. Expression of IFNαβ receptor in VECs was necessary to obtain the antitumor effects by PICLC and IFN-I was found to directly stimulate the secretion of T cell recruiting chemokines by VECs indicating that this cytokine-chemokine regulatory axis is crucial for recruiting effector T cells into the tumor parenchyma. Unexpectedly, these effects of PICLC were mostly observed in tumors and not in normal tissues.

CONCLUSIONS

These findings have strong implications for the improvement of all types of T cell-based immunotherapies for solid cancers. We predict that systemic administration of PICLC will improve immune checkpoint inhibitor therapy, adoptive cell therapies and therapeutic cancer vaccines.

A systematic review of ongoing clinical trials in optic pathway gliomas

INTRODUCTION

Optic pathway gliomas (OPGs), also known as Visual Pathway Gliomas, are insidious, debilitating tumours. They are most commonly WHO grade 1 pilocytic astrocytomas and frequently occur in patients with neurofibromatosis type 1. The location of OPGs within the optic pathway typically precludes complete resection or optimal radiation dosing, hence outcomes remain poor compared to many other low-grade gliomas. The aim of this systematic review was to formulate a comprehensive list of all current ongoing clinical trials that are specifically looking at clinical care of OPGs in order to identify trends in current research and provide an overview to guide future research efforts.

METHODS

This systematic review was conducted in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The Cochrane Controlled Register of Trials (CENTRAL) and ClinicalTrials.gov were searched. Inclusion and exclusion criteria were applied and final results were reviewed.

RESULTS

501 clinical trials were identified with the search strategy. All were screened and eligible studies extracted and reviewed. This yielded 36 ongoing clinical trials, 27 of which were pharmacological agents in phase I-III. The remaining trials were a mixture of biological agents, radiation optimisation, diagnostic imaging, surgical intervention, and a social function analysis.

CONCLUSION

OPG is a complex multifaceted disease, and advances in care require ongoing research efforts across a spectrum of different research fields. This review provides an update on the current state of research in OPG and summarises ongoing trials.

Targeting the innate immunoreceptor RIG-I overcomes melanoma-intrinsic resistance to T cell immunotherapy

Understanding tumor resistance to T cell immunotherapies is critical to improve patient outcomes. Our study revealed a role for transcriptional suppression of the tumor-intrinsic HLA class I (HLA-I) antigen processing and presentation machinery (APM) in therapy resistance. Low HLA-I APM mRNA levels in melanoma metastases before immune checkpoint blockade (ICB) correlated with nonresponsiveness to therapy and poor clinical outcome. Patient-derived melanoma cells with silenced HLA-I APM escaped recognition by autologous CD8+ T cells. However, targeted activation of the innate immunoreceptor RIG-I initiated de novo HLA-I APM transcription, thereby overcoming T cell resistance. Antigen presentation was restored in interferon-sensitive (IFN-sensitive) but also immunoedited IFN-resistant melanoma models through RIG-I-dependent stimulation of an IFN-independent salvage pathway involving IRF1 and IRF3. Likewise, enhanced HLA-I APM expression was detected in RIG-Ihi (DDX58hi) melanoma biopsies, correlating with improved patient survival. Induction of HLA-I APM by RIG-I synergized with antibodies blocking PD-1 and TIGIT inhibitory checkpoints in boosting the antitumor T cell activity of ICB nonresponders. Overall, the herein-identified IFN-independent effect of RIG-I on tumor antigen presentation and T cell recognition proposes innate immunoreceptor targeting as a strategy to overcome intrinsic T cell resistance of IFN-sensitive and IFN-resistant melanomas and improve clinical outcomes in immunotherapy.

The Use of Toll-Like Receptor Agonists in HIV-1 Cure Strategies

Toll-like receptors (TLRs) are a family of pattern recognition receptors and part of the first line of defense against invading microbes. In humans, we know of 10 different TLRs, which are expressed to varying degrees in immune cell subsets. Engaging TLRs through their specific ligands leads to activation of the innate immune system and secondarily priming of the adaptive immune system. Because of these unique properties, TLR agonists have been investigated as immunotherapy in cancer treatment for many years, but in recent years there has also been growing interest in the use of TLR agonists in the context of human immunodeficiency virus type 1 (HIV-1) cure research. The primary obstacle to curing HIV-1 is the presence of a latent viral reservoir in transcriptionally silent immune cells. Due to the very limited transcription of the integrated HIV-1 proviruses, latently infected cells cannot be targeted and cleared by immune effector mechanisms. TLR agonists are very interesting in this context because of their potential dual effects as latency reverting agents (LRAs) and immune modulatory compounds. Here, we review preclinical and clinical data on the impact of TLR stimulation on HIV-1 latency as well as antiviral and HIV-1-specific immunity. We also focus on the promising role of TLR agonists in combination strategies in HIV-1 cure research. Different combinations of TLR agonists and broadly neutralizing antibodies or TLRs agonists as adjuvants in HIV-1 vaccines have shown very encouraging results in non-human primate experiments and these concepts are now moving into clinical testing.

Cross-Presentation of Tumor Antigens Is Ruled by Synaptic Transfer of Vesicles among Dendritic Cell Subsets

Migratory dendritic cells (DCs) in tumors transport antigens and share them with lymph node resident DCs through cross-presentation. In this issue of Cancer Cell, Ruhland et al. demonstrate that transport and transfer of tumor antigens in vesicles is a dominant pathway to load resident DCs for presentation to T cells.

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.

Translating the Immunobiology of SBRT to Novel Therapeutic Combinations for Advanced Prostate Cancer

Stereotactic body radiotherapy (SBRT) is an increasingly used radiation modality for the treatment of both localized and metastatic prostate cancer. Substantial data suggests that prostate cancer may be more sensitive to higher doses of radiation per fraction due to its low α/β ratio. This increased sensitivity raises important questions as to how SBRT should be combined with systemic therapy for clinically significant prostate cancer, including whether androgen deprivation therapy retains its beneficial effects when combined with SBRT. Furthermore, pre-clinical and clinical data suggest pronounced immunomodulatory effects of SBRT, including observed improvements in T cell priming and trafficking. These data support investigational strategies combining SBRT with immunotherapy. Here we aim to review the data for the use of SBRT in both the local and metastatic disease settings as well as ongoing translational and clinical research examining combinations with ADT, immunotherapy and other targeted agents.

Immunomodulator polyinosinic-polycytidylic acid enhances the inhibitory effect of 13-cis-retinoic acid on neuroblastoma through a TLR3-related immunogenic-apoptotic response

High-risk neuroblastoma is associated with low long-term survival rates due to recurrence or metastasis. Retinoids, including 13-cis-retinoic acid (13cRA), are commonly used for the treatment of high-risk neuroblastoma after myeloablative therapy; however, there are significant side effects and resistance rates. In this study, we demonstrated that 13cRA has a better antiproliferative effect in MYCN-amplified neuroblastoma cells than in MYCN-nonamplified neuroblastoma cells. In MYCN-amplified SK-N-DZ cells, 13cRA induced significant upregulation of toll-like receptor 3 (TLR3) and mitochondrial antiviral-signaling protein (MAVS) expression in a time-dependent manner. Furthermore, poly (I:C), a synthetic agonist of TLR3, effectively synergized with 13cRA to enhance antiproliferative effects through upregulation of the innate immune signaling and the mitochondrial stress response, leading to augmentation of the apoptotic response in 13cRA-responsive cancer cells. In addition, the 13cRA/poly (I:C) combination induced neural differentiation through activation of retinoic acid receptors beta (RAR-β), restoring expression of α-thalassemia/mental retardation syndrome X-linked (ATRX) protein, and inhibiting vessel formation, leading to retarded tumor growth in a mouse xenograft model. These results suggest that the combination of poly (I:C) and RA may provide synergistic therapeutic benefits for treatment of patients with high-risk neuroblastoma.

Delivery of nucleic acid therapeutics for cancer immunotherapy

Cancer immunotherapy has shown great potential as witnessed by an increasing number of immuno-oncology drug approvals in the past few years. Meanwhile, the field of nucleic acid therapeutics has made significant advancement. Nucleic acid therapeutics, such as plasmids, antisense oligonucleotides (ASO), small interfering RNA (siRNA) and microRNA, messenger RNA (mRNA), immunomodulatory DNA/RNA, and gene-editing guide RNA (gRNA) are attractive due to their versatile abilities to alter the expression of target endogenous genes or even synthetic genes, and modulate the immune responses. These abilities can play vital roles in the development of novel immunotherapy strategies. However, limited by the intrinsic physicochemical properties such as negative charges, hydrophilicity, as well as susceptibility to enzymatic degradation, the delivery of nucleic acid therapeutics faces multiple challenges. It is therefore pivotal to develop drug delivery systems that can carry, protect, and specifically deliver and release nucleic acid therapeutics to target tissues and cells. In this review, we attempted to summarize recent advances in nucleic acid therapeutics and the delivery systems for these therapeutics in cancer immunotherapy.

Blood Eosinophilia is an on-Treatment Biomarker in Patients with Solid Tumors Undergoing Dendritic Cell Vaccination with Autologous Tumor-RNA

Background: The approvals of immune checkpoint inhibitors for several cancer types and the rapidly growing recognition that T cell-based immunotherapy significantly improves outcomes for cancer patients led to a re-emergence of cancer vaccines, including dendritic cell (DC)-based immunotherapy. Blood and tissue biomarkers to identify responders and long-term survivors and to optimize cost and cost-effectiveness of treatment are greatly needed. We wanted to investigate whether blood eosinophilia is a predictive biomarker for patients with solid tumors receiving vaccinations with DCs loaded with autologous tumor-RNA. Methods: In total, 67 patients with metastatic solid tumors, who we treated with autologous monocyte-derived DCs transfected with total tumor mRNA, were serially analyzed for eosinophil counts and survival over the course of up to 14 years. Eosinophilic counts were performed on peripheral blood smears. Results: Up to 87% of the patients treated with DC-based immunotherapy experienced at least once an eosinophilia of ≥ 5% after initiation of therapy; 61 % reached levels of ≥ 10% eosinophils, and 13% of patients showed eosinophil counts of 20% or above. While prevaccination eosinophil levels were not associated with survival, patients with blood eosinophilia at any point after initiation of DC-based immunotherapy showed a trend towards longer survival. There was a statistically significant difference for the patients with eosinophil counts of 20% or more (p = 0.03). In those patients, survival was prolonged to a median of 58 months (range 2–111 months), compared to a median of 20 months (range 0–119 months) in patients with lower eosinophil counts. In 12% of the patients, an immediate increase in eosinophil count of at least 10 percentage points could be detected after the first vaccine, which also appeared to correlate with survival (65 vs. 24 months; p = 0.06). Conclusion: Blood eosinophilia appears to be an early, on-therapy biomarker in patients with solid tumors undergoing vaccination with RNA-transfected DC, specifically autologous tumor mRNA-transfected DC vaccines, and it correlates with long-term patient outcome. Eosinophilia should be systematically investigated in future trials.

Immunological effects of adjuvants in subsets of antigen presenting cells of cancer patients undergoing chemotherapy

Background

We have previously shown that HCC patients and healthy subjects are equally responsive to a RNAdjuvant^®, a novel TLR-7/8/RIG-I agonist based on noncoding RNA developed by CureVac, by an ex vivo evaluation. However, the immunological effect of adjuvants on immune cells from cancer patients undergoing chemotherapy remains to be demonstrated. Different adjuvants currently used in cancer vaccine clinical trials were evaluated in the present study on immune cells from cancer patients before and after chemotherapy in an ex vivo setting.

Methods

PBMCs were obtained from 4 healthy volunteers and 23 patients affected by either colon (OMA) or lung cancer (OT). The effect of CpG, Poly I:C, Imiquimod and RNA-based adjuvant (RNAdjuvant^®) was assessed using a multiparametric approach to analyze network dynamics of early immune responses. Evaluation of CD80, CD86 and HLA-DR expression as well as the downstream effect on CD4⁺ T cell phenotyping was performed by flow cytometry; cytokine and chemokine production was evaluated by Bio-Plex ProTM.

Results

Treatment with RNAdjuvant^® induced the strongest response in cancer patients in terms of activation of innate and adoptive immunity. Indeed, CD80, CD86 and HLA-DR expression was found upregulated in circulating dendritic cells, which promoted a CD4⁺ T cell differentiation towards an effector phenotype. RNAdjuvant^® was the only one to induce most of the cytokines/chemokines tested with a pronounced Th1 cytokine pattern. According to the different parameters evaluated in the study, no clear cut difference in immune response to adjuvants was observed between healthy subjects and cancer patients. Moreover, in the latter group, the chemotherapy treatment did not consistently correlate to a significant altered response in the different parameters.

Conclusions

The present study is the first analysis of immunological effects induced by adjuvants in cancer patients who undergo chemotherapy, who are enrolled in the currently ongoing cancer vaccine clinical trials. The results show that the RNAdjuvant^® is a potent and Th1 driving adjuvant, compared to those tested in the present study. Most importantly, it is demonstrated that chemotherapy does not significantly impair the immune system, implying that cancer patients are likely to respond to a cancer vaccine even after a chemotherapy treatment.

Dendritic cells in cancer immunology and immunotherapy

Dendritic cells (DCs) are a diverse group of specialized antigen-presenting cells with key roles in the initiation and regulation of innate and adaptive immune responses. As such, there is currently much interest in modulating DC function to improve cancer immunotherapy. Many strategies have been developed to target DCs in cancer, such as the administration of antigens with immunomodulators that mobilize and activate endogenous DCs, as well as the generation of DC-based vaccines. A better understanding of the diversity and functions of DC subsets and of how these are shaped by the tumour microenvironment could lead to improved therapies for cancer. Here we will outline how different DC subsets influence immunity and tolerance in cancer settings and discuss the implications for both established cancer treatments and novel immunotherapy strategies.

The role of dendritic cells in cancer

Cancer immunotherapy harnesses the ability of the immune system to recognize and eliminate cancer. The potent ability of dendritic cells (DCs) to initiate and regulate adaptive immune responses underpins the successful generation of anti-tumor immune responses. DCs are a heterogeneous leukocyte population comprised of distinct subsets that drive specific types of immune responses. Understanding how DCs induce tumor immune responses and the mechanisms adopted by tumors to evade DC surveillance is essential to render immunotherapies more effective. This review discusses current knowledge of the roles played by different DC subsets in human cancer and how these might be manipulated as new immunotherapeutics to improve CD8⁺ T cell-mediated immune responses, with a particular focus on the conventional type 1 DCs (cDC1).

Poly-ICLC, a TLR3 Agonist, Induces Transient Innate Immune Responses in Patients With Treated HIV-Infection: A Randomized Double-Blinded Placebo Controlled Trial

Objective: Toll-like receptor-3 agonist Poly-ICLC has been known to activate immune cells and induce HIV replication in pre-clinical experiments. In this study we investigated if Poly-ICLC could be used for disrupting HIV latency while simultaneously enhancing innate immune responses.

Design: This was a randomized, placebo-controlled, double-blinded trial in aviremic, cART-treated HIV-infected subjects. Participants (n = 15) were randomized 3:1 to receive two consecutive daily doses of Poly-ICLC (1.4 mg subcutaneously) vs. placebo. Subjects were observed for adverse events, immune activation, and viral replication.

Methods: Besides primary outcomes of safety and tolerability, several longitudinal immune parameters were evaluated including immune cell phenotype and function via flowcytometry, ELISA, and transcriptional profiling. PCR assays for plasma HIV-1 RNA, CD4⁺ T cell-associated HIV-1 RNA, and proviral DNA were performed to measure HIV reservoirs and latency.

Results: Poly-ICLC was overall safe and well-tolerated. Poly-ICLC-related adverse events were Grade 1/2, with the exception of one Grade 3 neutropenia which was short-lived. Mild Injection site reactions were observed in nearly all participants in the Poly-ICLC arm. Transcriptional analyses revealed upregulation of innate immune pathways in PBMCs following Poly-ICLC treatment, including strong interferon signaling accompanied by transient increases in circulating IP-10 (CXCL10) levels. These responses generally peaked by 24–48 h after the first injection and returned to baseline by day 8. CD4⁺ T cell number and phenotype were unchanged, plasma viral control was maintained and no significant effect on HIV reservoirs was observed.

Conclusions: These finding suggest that Poly-ICLC could be safely used for inducing transient innate immune responses in treated HIV⁺ subjects indicating promise as an adjuvant for HIV therapeutic vaccines.

Trial Registration:www.ClinicalTrials.gov, identifier: NCT02071095.

Epigenetic therapy in immune-oncology

DNA methylation inhibitors have become the mainstay for treatment of certain haematological malignancies. In addition to their abilities to reactivate genes, including tumour suppressors, that have acquired DNA methylation during carcinogenesis, they induce the expression of thousands of transposable elements including endogenous retroviruses and latent cancer testis antigens normally silenced by DNA methylation in most somatic cells. This results in a state of viral mimicry in which treated cells mount an innate immune response by turning on viral defence genes and potentially expressing neoantigens. Furthermore, these changes mediated by DNA methylation inhibitors can also alter the function of immune cells relevant to acquired immunity. Additionally, other inhibitors of epigenetic processes, such as histone deacetylases, methylases and demethylases, can elicit similar effects either individually or in combinations with DNA methylation inhibitors. These findings together with rapid development of immunotherapies open new avenues for cancer treatment.

Poly(I:C) stimulation is superior than Imiquimod to induce the antitumoral functional profile of tumor-conditioned macrophages

Macrophage plasticity is the ability of mononuclear phagocytes to change phenotype, function, and genetic reprogramming upon encounter of specific local stimuli. In the tumor microenvironment, Tumor-Associated Macrophages (TAMs) acquire an immune-suppressive and tumor-promoting phenotype. With the aim to re-educate TAMs to antitumor effectors, in this study, we used two immunestimulatory compounds: the TLR7 agonist Imiquimod (IMQ) and the TLR3 agonist Poly(I:C). To better mimic in vitro the response of TAMs, we used Tumor-Conditioned Macrophages (TC-Mϕ) differentiated in the presence of tumor cell supernatants. Our results show that TC-Mϕ respond differently from conventional M2-polarized macrophages. Upon stimulation with IMQ, TC-Mϕ did not upregulate major histocompatibility complex (MHC II) molecules and unexpectedly expressed increased CD206. With both compounds, TC-Mϕ produced higher levels of inflammatory cytokines than M2 macrophages. IMQ and Poly(I:C) differed in the types of regulated genes and secreted mediators. Reflecting their signaling pathways, only IMQ significantly induced IL-1β and IL-6, while only Poly(I:C) stimulated CXCL10, and both upregulated CCL5. Of note, using a novel cytotoxicity assay, Poly(I:C), but not IMQ, was effective in triggering the cytotoxic activity of TC-Mϕ against cancer cells. Overall, the results demonstrate that Poly(I:C) stimulation of TC-Mϕ is superior than IMQ in terms of macrophage re-education toward antitumor effectors.

Therapeutic Targeting of RIG-I and MDA5 Might Not Lead to the Same Rome

RIG-I and MDA5 receptors are key sensors of pathogen-associated molecular pattern (PAMP)-containing viral RNA and transduce downstream signals to activate an antiviral and immunomodulatory response. Fifteen years of research have put them at the center of an ongoing hunt for novel pharmacological pan-antivirals, vaccine adjuvants, and antitumor strategies. Current knowledge testifies to the redundant, but also distinct, functions mediated by RIG-I and MDA5, opening opportunities for the use of specific and potent nucleic acid agonists. We critically discuss the evidence and remaining knowledge gaps that have an impact on the choice and design of optimal RNA ligands to achieve an appropriate immunostimulatory response, with limited adverse effects, for prophylactic and therapeutic interventions against viruses and cancer in humans.

The Emerging Role of Checkpoint Inhibition in Microsatellite Stable Colorectal Cancer

Checkpoint inhibitor therapy has introduced a revolution in contemporary anticancer therapy. It has led to dramatic improvements in patient outcomes and has spawned tremendous research into novel immunomodulatory agents and combination therapy that has changed the trajectory of cancer care. However, clinical benefit in patients with colorectal cancer has been generally limited to tumors with loss of mismatch repair function and those with specific germline mutations in the DNA polymerase gene. Unfortunately, tumors with these specific mutator phenotypes are in the minority. Recent pre-clinical and clinical studies have begun to reveal encouraging results suggesting that checkpoint inhibitor therapy can be expanded to an increasing number of colorectal tumors with microsatellite stability and the absence of traditional predictive biomarkers of checkpoint inhibitor response. These studies generally rely on combinations of checkpoint inhibitors with chemotherapy, molecular targeted therapy, radiation therapy, or other novel immunomodulatory agents. This article will review the most current data in microsatellite stable colorectal cancer.

Anti-tumor macrophages activated by ferumoxytol combined or surface-functionalized with the TLR3 agonist poly (I : C) promote melanoma regression

Macrophages orchestrate inflammation and control the promotion or inhibition of tumors and metastasis. Ferumoxytol (FMT), a clinically approved iron oxide nanoparticle, possesses anti-tumor therapeutic potential by inducing pro-inflammatory macrophage polarization. Toll-like receptor 3 (TLR3) activation also potently enhances the anti-tumor response of immune cells. Herein, the anti-tumor potential of macrophages harnessed by FMT combined with the TLR3 agonist, poly (I:C) (PIC), and FP-NPs (nanoparticles composed of amino-modified FMT (FMT-NH2) surface functionalized with PIC) was explored. Methods: Proliferation of B16F10 cells co-cultured with macrophages was measured using immunofluorescence or flow cytometry (FCM). Phagocytosis was analyzed using FCM and fluorescence imaging. FP-NPs were prepared through electrostatic interactions and their properties were characterized using dynamic light scattering, transmission electron microscopy, and gel retardation assay. Anti-tumor and anti-metastasis effects were evaluated in B16F10 tumor-bearing mice, and tumor-infiltrating immunocytes were detected by immunofluorescence staining and FCM. Results: FMT, PIC, or the combination of both hardly impaired B16F10 cell viability. However, FMT combined with PIC synergistically inhibited their proliferation by shifting macrophages to a tumoricidal phenotype with upregulated TNF-α and iNOS, increased NO secretion and augmented phagocytosis induced by NOX2-derived ROS in vitro. Combined treatment with FMT/PIC and FMT-NH2/PIC respectively resulted in primary melanoma regression and alleviated pulmonary metastasis with elevated pro-inflammatory macrophage infiltration and upregulation of pro-inflammatory genes in vivo. In comparison, FP-NPs with properties of internalization by macrophages and accumulation in the lung produced a more pronounced anti-metastatic effect accompanied with decreased myeloid-derived suppressor cells, and tumor-associated macrophages shifted to M1 phenotype. In vitro mechanistic studies revealed that FP-NPs nanoparticles barely affected B16F10 cell viability, but specifically retarded their growth by steering macrophages to M1 phenotype through NF-κB signaling. Conclusion: FMT synergized with the TLR3 agonist PIC either in combination or as a nano-composition to induce macrophage activation for primary and metastatic melanoma regression, and the nano-composition of FP-NPs exhibited a more superior anti-metastatic efficacy.

The double stranded RNA analog poly-IC elicits both robust IFN-λ production and oncolytic activity in human gastrointestinal cancer cells

Purpose

Type III IFN (IFN-λ) is the dominant frontline response over type I IFN in human normal intestinal epithelial cells upon viral infection, this response being mimicked by the dsRNA analog poly-IC. Poly-IC also induces cell death in murine intestinal crypts ex vivo. Here we examined whether these innate defense functions of normal intestinal epithelial cells are recapitulated in gastrointestinal carcinoma cells so that they could be harnessed to exert both immunoadjuvant and oncolytic functions, an unknown issue yet.

Experimental design

Four human gastrointestinal carcinoma cell lines versus the Jurkat lymphoma cell line were used to assess the effects of intracellular poly-IC on i) IFN-λ secretion and cell proliferation and ii) role of NFκB signaling using the NFκB inhibitory peptide SN50 as a screening probe and a siRNA approach.

Results

Poly-IC induced in all cell lines except Jurkat both a robust IFN-λ secretion and a cytoreductive effect on adherent cells, restricted to proliferating cells and associated with cellular shedding and reduced clonogenicity of the shed cells. Collectively these findings demonstrate the oncolytic activity of poly-IC. Inhibiting NFκB in T84 cells using a siRNA approach decreased IFN-λ production without protecting the cells from the poly-IC oncolytic effects. In line with these findings IFN-λ, that upregulated the anti-viral protein MxA, was unable per se to alter T84 cell proliferation.

Conclusion

Our demonstration that poly-IC-induced concomitant recapitulation of two innate functions of normal intestine, i.e. IFN-λ production and cell death, by human gastrointestinal cancer cells opens new perspectives in gastrointestinal cancer treatment.

For Whom the Cell Tolls? Intratumoral Treatment Links Innate and Adaptive Immunity

Intratumoral immunotherapy can potentially modulate the tumor microenvironment (TME) and potentiate the effects of concomitant or sequential systemic immunotherapies. Intratumoral administration of different Toll-like receptor agonists, including TLR4, can potentiate these effects through innate and adaptive immunity connection.See related article by Bhatia et al., p. 1185.