Overcoming resistance to immune checkpoint blockade with RNA-loaded nanoparticles.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 117-117
Author(s):  
Elias Joseph Sayour ◽  
Adam Grippin ◽  
Duane Anthony Mitchell
Keyword(s):  
Immune Checkpoint ◽  
Tumor Antigens ◽  
Defense Mechanism ◽  
Immune Escape ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Type I ◽  
Dependent Manner ◽  
Activation Markers ◽  
Cell Immunity

117 Background: While checkpoint blockade has shown promising survival benefits in patients with solid tumors, immune escape through loss of MHCI expression juxtaposed to an immunoregulatory milieu remain significant hurdles. To overcome these limitations, we developed a novel treatment platform, which leverages the use of commercially available and clinically translatable nanoparticles (NPs) that can be combined with tumor-derived RNA to activate systemic immunity and re-program the intratumoral microenvironment from a regulatory into an immune activated locale. Methods: Since local vaccination strategies are mired with poor immunogenicity, we assessed if i.v. delivery of tumor-derived RNA encapsulated in lipophilic NPs could activate peripheral and intratumoral antigen presenting cells (APCs) for induction of therapeutic anti-tumor immunity in pre-clinical murine melanoma models. Results: We identified a clinically translatable NP formulation that when administered intravenously, mediates release of inflammatory cytokines (i.e. CCL2, IFN-alpha) into serum, systemically activates host APCs in reticuloendothelial organs, and induces precipitous upregulation of MHCI and immune activation markers (i.e. CD86) within the tumor microenvironment. Both model-antigen encoding RNA and physiologically-relevant tumor-derived RNA, when encapsulated in NPs, could expand potent anti-tumor T-cell immunity. We demonstrated that RNA-NPs harness the anti-viral defense mechanism against tumor antigens in a type I interferon dependent manner, and can be further engineered to deliver combinatorial therapies by co-encapsulating mRNAs encoding for immunomodulatory molecules (i.e. HCV PAMPs, GM-CSF). In a pre-clinical melanoma model, RNA-NPs mediate anti-tumor efficacy and significantly enhance activity of immune checkpoint mAbs when used in combination. Conclusions: By employing a systemic RNA-NP formulation encoding for both tumor RNAs and immunomodulatory molecules, as an innovative and versatile platform for delivering combinatorial therapeutics via a single treatment modality, this platform can be harnessed to simultaneously target tumor antigens and re-program the intratumoral microenvironment

scholarly journals Targeting MDSC for Immune-Checkpoint Blockade in Cancer Immunotherapy: Current Progress and New Prospects

2021 ◽  
Vol 15 ◽  
pp. 117955492110355
Author(s):  
Tianhang Li ◽  
Tianyao Liu ◽  
Wenjie Zhu ◽  
Shangxun Xie ◽  
Zihan Zhao ◽  
...  
Keyword(s):  
Immune Checkpoint ◽  
Immune Escape ◽  
Suppressor Cell ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Great Promise ◽  
Therapy Process ◽  
Myeloid Derived Suppressor Cell ◽  
Anti Cancer ◽  
Immune Suppressor

Immune-checkpoint blockade (ICB) demonstrated inspiring effect and great promise in anti-cancer therapy. However, many obstacles, such as drug resistance and difficulty in patient selection, limited the efficacy of ICB therapy and awaited to be overcome. By timely identification and intervention of the key immune-suppressive promotors in the tumor microenvironment (TME), we may better understand the mechanisms of cancer immune-escape and use novel strategies to enhance the therapeutic effect of ICB. Myeloid-derived suppressor cell (MDSC) is recognized as a major immune suppressor in the TME. In this review, we summarized the roles MDSC played in the cancer context, focusing on its negative biologic functions in ICB therapy, discussed the strategies targeted on MDSC to optimize the diagnosis and therapy process of ICB and improve the efficacy of ICB therapy against malignancies.

scholarly journals Combination of epigenetic regulation with gene therapy-mediated immune checkpoint blockade induces anti-tumour effects and immune response in vivo

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Huapan Fang ◽  
Zhaopei Guo ◽  
Jie Chen ◽  
Lin Lin ◽  
Yingying Hu ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Immune Response ◽  
Epigenetic Regulation ◽  
Immune Checkpoint ◽  
Immune Escape ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Immune Memory ◽  
Escape Mechanism ◽  
Immune Escape Mechanism

AbstractImmunotherapy has become a powerful cancer treatment, but only a small fraction of patients have achieved durable benefits due to the immune escape mechanism. In this study, epigenetic regulation is combined with gene therapy-mediated immune checkpoint blockade to relieve this immune escape mechanism. PPD (i.e., mPEG-b-PLG/PEI-RT3/DNA) is developed to mediate plasmid-encoding shPD-L1 delivery by introducing multiple interactions (i.e., electrostatic, hydrogen bonding, and hydrophobic interactions) and polyproline II (PPII)-helix conformation, which downregulates PD-L1 expression on tumour cells to relieve the immunosuppression of T cells. Zebularine (abbreviated as Zeb), a DNA methyltransferase inhibitor (DNMTi), is used for the epigenetic regulation of the tumour immune microenvironment, thus inducing DC maturation and MHC I molecule expression to enhance antigen presentation. PPD plus Zeb combination therapy initiates a systemic anti-tumour immune response and effectively prevents tumour relapse and metastasis by generating durable immune memory. This strategy provides a scheme for tumour treatment and the inhibition of relapse and metastasis.

scholarly journals BCG vaccine and COVID-19: implications for infection prophylaxis and cancer immunotherapy

2020 ◽  
Vol 8 (2) ◽  
pp. e001119 ◽  
Author(s):  
Madhuri Koti ◽  
Alvaro Morales ◽  
Charles H Graham ◽  
David Robert Siemens
Keyword(s):  
Immune Checkpoint ◽  
Critical Role ◽  
Immune Checkpoint Blockade ◽  
Lessons Learned ◽  
Checkpoint Blockade ◽  
Childhood Vaccination ◽  
Infection Prevalence ◽  
Type I ◽  
Infection Prophylaxis ◽  
Vaccination Programs

The COVID-19 pandemic has killed over 400 000 people globally. Ecological evidence indicates that countries with national universal BCG vaccination programs for tuberculosis (TB) prevention have a much lower incidence of severe COVID-19 and mortality compared with those that do not have such programs. BCG is a century old vaccine used for TB prevention via infant/childhood vaccination in lowto middle-income countries with high infection prevalence rate and is known to reduce all-cause neonatal mortality. BCG remains the standard immunotherapy treatment for patients with high-risk non-muscle invasive bladder cancer globally for more than 44 years. Several trials are, therefore, investigating BCG as a prophylactic against COVID-19 in healthcare workers and the elderly. In this commentary, we discuss the potential mechanisms that may underlie BCG associated heterologous protection with a focus on tertiary lymphoid structure (TLS) organogenesis. Given the significance of TLSs in mucosal immunity, their association with positive prognosis and response to immune checkpoint blockade with a critical role of Type I interferon (IFN-1) in inducing these, we also discuss potentiating TLS formation as a promising approach to enhance anti-tumor immunity. We propose that lessons learned from BCG immunotherapy success could be applied to not only augment such microbe-based therapeutics but also lead to similar adjunctive IFN-1 activating approaches to improve response to immune checkpoint blockade therapy in cancer.

scholarly journals cGAS is essential for the antitumor effect of immune checkpoint blockade

2017 ◽  
Vol 114 (7) ◽  
pp. 1637-1642 ◽  
Author(s):  
Hua Wang ◽  
Shuiqing Hu ◽  
Xiang Chen ◽  
Heping Shi ◽  
Chuo Chen ◽  
...  
Keyword(s):  
Immune Checkpoint ◽  
Antitumor Effect ◽  
Adaptor Protein ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Type I Interferons ◽  
Type I ◽  
Antibody Treatment ◽  
Antitumor Effects ◽  
Cross Presentation

cGMP-AMP (cGAMP) synthase (cGAS) is a cytosolic DNA sensor that activates innate immune responses. cGAS catalyzes the synthesis of cGAMP, which functions as a second messenger that binds and activates the adaptor protein STING to induce type I interferons (IFNs) and other immune modulatory molecules. Here we show that cGAS is indispensable for the antitumor effect of immune checkpoint blockade in mice. Wild-type, but not cGAS-deficient, mice exhibited slower growth of B16 melanomas in response to a PD-L1 antibody treatment. Consistently, intramuscular delivery of cGAMP inhibited melanoma growth and prolonged the survival of the tumor-bearing mice. The combination of cGAMP and PD-L1 antibody exerted stronger antitumor effects than did either treatment alone. cGAMP treatment activated dendritic cells and enhanced cross-presentation of tumor-associated antigens to CD8 T cells. These results indicate that activation of the cGAS pathway is important for intrinsic antitumor immunity and that cGAMP may be used directly for cancer immunotherapy.

scholarly journals Immunogenomic profile of colorectal cancer response to immune checkpoint blockade

2020 ◽  
Author(s):  
Michele Bortolomeazzi ◽  
Mohamed Reda Keddar ◽  
Lucia Montorsi ◽  
Amelia Acha-Sagredo ◽  
Lorena Benedetti ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Immune Checkpoint ◽  
Immune Escape ◽  
Cell Receptor ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Critical Threshold ◽  
Mutational Burden ◽  
Antigen Presenting

To dissect the determinants of the heterogeneous response of colorectal cancer (CRC) to immune checkpoint blockade, we profile tumour and immune infiltrates of 721 cancer regions from 29 patients treated with Pembrolizumab or Nivolumab. Combining multi-regional whole exome, RNA and T-cell receptor sequencing we show that anti-PD1 agents are most effective in CRCs with high mutational burden and low activation of the WNT pathway. However, above a critical threshold defining the hypermutated phenotype, response is no longer associated with mutational burden but rather with high clonality of immunogenic mutations, expanded T cells and active immune escape mechanisms. Using high-dimensional imaging mass cytometry and multiplexed immunofluorescence, we observe that responsive hypermutated CRCs are rich in cytotoxic and proliferating PD1-expressing CD8 infiltrates interacting with high-density clusters of PDL1-expressing antigen presenting macrophages. We propose that anti-PD1 agents release the PD1-PDL1 interaction between CD8 T cells and macrophages thus promoting their expansion in intra-tumour niches.

scholarly journals PARPi triggers STING-dependent immune response and enhances therapeutic efficacy of immune checkpoint blockade independent of BRCAness

2018 ◽  
Author(s):  
Jianfeng Shen ◽  
Wei Zhao ◽  
Zhenlin Ju ◽  
Lulu Wang ◽  
Yang Peng ◽  
...  
Keyword(s):  
Immune Checkpoint ◽  
Therapeutic Efficacy ◽  
Parp Inhibitors ◽  
Immune Checkpoint Blockade ◽  
Dna Lesions ◽  
Checkpoint Blockade ◽  
Type I Interferons ◽  
Therapeutic Effects ◽  
Type I ◽  
Dna Double Strand Breaks

AbstractPoly-(ADP-ribose) polymerase (PARP) inhibitors (PARPis) have shown remarkable therapeutic efficacy against BRCA1/2 mutant cancers through a synthetic lethal interaction. PARPis are believed to exert their therapeutic effects mainly through the blockade of single-strand DNA damage repair, which leads to the accumulation of toxic DNA double strand breaks, specifically in cancer cells with DNA repair deficiency (BCRAness), including those harboring BRCA1/2 mutations. Here, we show that PARPis modulate immune reposes, which contribute to their therapeutic effects independent of BRCA1/2 mutations. The mechanism underlying this PARPi-induced reprogramming of anti-tumor microenvironment involves a promoted accumulation of cytosolic DNA fragments due to unresolved DNA lesions. This in turn activates the DNA sensing cGAS-STING pathway and stimulates production of type I interferons. Ultimately, these events promote PARPi-induced antitumor immunity independent of BRCAness, which can be further enhanced by immune checkpoint blockade. Our results may provide a mechanistic rationale for using PARPis as immunomodulatory agents to harness therapeutic efficacy of immune checkpoint blockade.

scholarly journals Antitumor Peptide-Based Vaccine in the Limelight

Vaccines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 70
Author(s):  
Takumi Kumai ◽  
Hidekiyo Yamaki ◽  
Michihisa Kono ◽  
Ryusuke Hayashi ◽  
Risa Wakisaka ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Immune Cells ◽  
Immune Checkpoint ◽  
Tumor Antigens ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Recent Experimental Data ◽  
Proof Of Concept ◽  
Cell Responses ◽  
Tumor Reduction

The success of the immune checkpoint blockade has provided a proof of concept that immune cells are capable of attacking tumors in the clinic. However, clinical benefit is only observed in less than 20% of the patients due to the non-specific activation of immune cells by the immune checkpoint blockade. Developing tumor-specific immune responses is a challenging task that can be achieved by targeting tumor antigens to generate tumor-specific T-cell responses. The recent advancements in peptide-based immunotherapy have encouraged clinicians and patients who are struggling with cancer that is otherwise non-treatable with current therapeutics. By selecting appropriate epitopes from tumor antigens with suitable adjuvants, peptides can elicit robust antitumor responses in both mice and humans. Although recent experimental data and clinical trials suggest the potency of tumor reduction by peptide-based vaccines, earlier clinical trials based on the inadequate hypothesis have misled that peptide vaccines are not efficient in eliminating tumor cells. In this review, we highlighted the recent evidence that supports the rationale of peptide-based antitumor vaccines. We also discussed the strategies to select the optimal epitope for vaccines and the mechanism of how adjuvants increase the efficacy of this promising approach to treat cancer.

scholarly journals Targeting the IRE1α/XBP1s pathway suppresses CARM1-expressing ovarian cancer

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jianhuang Lin ◽  
Heng Liu ◽  
Takeshi Fukumoto ◽  
Joseph Zundell ◽  
Qingqing Yan ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Stress Response ◽  
Er Stress ◽  
Cancer Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Ovarian Cancer Cells ◽  
Dependent Manner ◽  
Er Stress Response

AbstractCARM1 is often overexpressed in human cancers including in ovarian cancer. However, therapeutic approaches based on CARM1 expression remain to be an unmet need. Cancer cells exploit adaptive responses such as the endoplasmic reticulum (ER) stress response for their survival through activating pathways such as the IRE1α/XBP1s pathway. Here, we report that CARM1-expressing ovarian cancer cells are selectively sensitive to inhibition of the IRE1α/XBP1s pathway. CARM1 regulates XBP1s target gene expression and directly interacts with XBP1s during ER stress response. Inhibition of the IRE1α/XBP1s pathway was effective against ovarian cancer in a CARM1-dependent manner both in vitro and in vivo in orthotopic and patient-derived xenograft models. In addition, IRE1α inhibitor B-I09 synergizes with immune checkpoint blockade anti-PD1 antibody in an immunocompetent CARM1-expressing ovarian cancer model. Our data show that pharmacological inhibition of the IRE1α/XBP1s pathway alone or in combination with immune checkpoint blockade represents a therapeutic strategy for CARM1-expressing cancers.

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