scholarly journals Novel induction of CD40 expression by tumor cells with RAS/RAF/PI3K pathway inhibition augments response to checkpoint blockade

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Chi Yan ◽  
Nabil Saleh ◽  
Jinming Yang ◽  
Caroline A. Nebhan ◽  
Anna E. Vilgelm ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Pi3k Pathway ◽  
Melanoma Cells ◽  
Checkpoint Blockade ◽  
Tumor Growth Inhibition ◽  
Activated T Cells ◽  
Melanoma Patients ◽  
Cd40 Expression ◽  
Pathway Inhibition

Abstract Background While immune checkpoint blockade (ICB) is the current first-line treatment for metastatic melanoma, it is effective for ~ 52% of patients and has dangerous side effects. The objective here was to identify the feasibility and mechanism of RAS/RAF/PI3K pathway inhibition in melanoma to sensitize tumors to ICB therapy. Methods Rigosertib (RGS) is a non-ATP-competitive small molecule RAS mimetic. RGS monotherapy or in combination therapy with ICB were investigated using immunocompetent mouse models of BRAFwt and BRAFmut melanoma and analyzed in reference to patient data. Results RGS treatment (300 mg/kg) was well tolerated in mice and resulted in ~ 50% inhibition of tumor growth as monotherapy and ~ 70% inhibition in combination with αPD1 + αCTLA4. RGS-induced tumor growth inhibition depends on CD40 upregulation in melanoma cells followed by immunogenic cell death, leading to enriched dendritic cells and activated T cells in the tumor microenvironment. The RGS-initiated tumor suppression was partially reversed by either knockdown of CD40 expression in melanoma cells or depletion of CD8+ cytotoxic T cells. Treatment with either dabrafenib and trametinib or with RGS, increased CD40+SOX10+ melanoma cells in the tumors of melanoma patients and patient-derived xenografts. High CD40 expression level correlates with beneficial T-cell responses and better survival in a TCGA dataset from melanoma patients. Expression of CD40 by melanoma cells is associated with therapeutic response to RAF/MEK inhibition and ICB. Conclusions Our data support the therapeutic use of RGS + αPD1 + αCTLA4 in RAS/RAF/PI3K pathway-activated melanomas and point to the need for clinical trials of RGS + ICB for melanoma patients who do not respond to ICB alone. Trial registration NCT01205815 (Sept 17, 2010). Graphical abstract

245 Human TLR8 knock-in mice potentiate immunotherapy responses of MC38 syngeneic tumors

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A264-A264
Author(s):  
Shanshan Qi ◽  
Hongjuan Zhang ◽  
Ruilin Sun ◽  
Annie An ◽  
Henry Li ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Cancer Immunotherapy ◽  
Tumor Regression ◽  
Tumor Growth Rate ◽  
Tumor Growth Inhibition ◽  
List Type ◽  
Rna Recognition ◽  
Ethical Guidelines ◽  
Ifn Γ

BackgroundToll-like receptors (TLRs) serve critical roles in mediating innate immune responses against many pathogens. However, they may also bind to endogenous ligands and lead to the pathogenesis of autoimmunity. Although TLR8 belongs to the same TLR family as TLR7, its role in inflammation and tumor progression is not yet fully understood due to the lack of suitable animal models. In humans, both TLR7 and TLR8 recognize single-stranded self-RNA, viral RNA, and synthetic small molecule agonists.1, 2 However, mouse Tlr8 is non-functional due to the absence of 5 amino acids necessary for RNA recognition. In order to create a mouse model with functional TLR8, we replaced exon 3 of mouse Tlr8 with human TLR8, therefore developing a hTLR8 knock-in (KI) model. Both heterozygous and homozygous hTLR8 KI mice are viable with inflammatory phenotypes, i.e. enlarged spleens and livers, and significantly higher IL-12 p40 levels under TLR8 agonist treatment. In this study, we evaluated the potential use of hTLR8 mice for cancer immunotherapy studies.MethodshTLR8 mice, together with naïve C57BL/6 mice, were inoculated with MC38 syngeneic tumor cells. Tumor bearing mice were grouped at a mean tumor volume of approximately 100 mm3 for treatment with PBS or 10 mg/kg anti-PD-1 (RMP1-14) antibody. At the efficacy endpoint, spleens and tumors were collected for flow cytometry profiling.ResultsAnti-PD-1 treatment of MC38 tumors in naïve C57BL/6 led to moderate tumor growth inhibition (TGI = 54%). Interestingly, anti-PD-1 treatment showed improved efficacy in hTLR8 mice (TGI = 79%), including 2/10 tumors with complete tumor regression. In comparison, non-treated MC38 tumor growth rate was slower in hTLR8 mice than in naïve mice. Anti-PD-1 treated hTLR8 mice also had significantly increased IFN-γ and TNF-a positive CD4+ T cells in the spleen, along with higher numbers of differentiated effector T cells. In addition, hTLR8 mice have activated dendritic cells and macrophages, acting as critical steps in initiation of the inflammatory process, with higher levels of pro-inflammatory cytokines, such as IL-6, IFN-γ, TNF-a, and IL-1β, which may promote Th1 priming and differentiation of T cells into IFN-γ or TNF-a producing cells.ConclusionshTLR8 mice offer a great tool to model cancer immunotherapy in an inflammatory/autoimmunity prone background. Moreover, hTLR8 mice can be effectively used to shift a ‘cold’ tumor phenotype to ‘hot’ tumors in a syngeneic setting.Ethics ApprovalAnimal experiments were conducted in accordance with animal welfare law, approved by local authorities, and in accordance with the ethical guidelines of CrownBio (Taicang).ReferencesKugelberg E. Making mice more human the TLR8 way. Nat Rev Immunol 2014;14:6.Guiducci C, Gong M, Cepika A-M, et al. RNA recognition by human TLR8 can lead to autoimmune inflammation. J Exp Med 2013;210:2903–2919.

scholarly journals Checkpoint blockade accelerates a novel switch from an NKT-driven TNFα response toward a T cell driven IFN-γ response within the tumor microenvironment

2021 ◽  
Vol 9 (6) ◽  
pp. e002269
Author(s):  
Shota Aoyama ◽  
Ryosuke Nakagawa ◽  
Satoshi Nemoto ◽  
Patricio Perez-Villarroel ◽  
James J Mulé ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Ex Vivo ◽  
T Cell Response ◽  
Effector Function ◽  
Checkpoint Blockade ◽  
Necrosis Factor Alpha ◽  
Ifn Γ

BackgroundThe temporal response to checkpoint blockade (CB) is incompletely understood. Here, we profiled the tumor infiltrating lymphocyte (TIL) landscape in response to combination checkpoint blockade at two distinct timepoints of solid tumor growth.MethodsC57BL/6 mice bearing subcutaneous MC38 tumors were treated with anti-PD-1 and/or anti-CTLA-4 antibodies. At 11 or 21 days, TIL phenotype and effector function were analyzed in excised tumor digests using high parameter flow cytometry. The contributions of major TIL populations toward overall response were then assessed using ex vivo cytotoxicity and in vivo tumor growth assays.ResultsThe distribution and effector function among 37 distinct TIL populations shifted dramatically between early and late MC38 growth. At 11 days, the immune response was dominated by Tumor necrosis factor alpha (TNFα)-producing NKT, representing over half of all TIL. These were accompanied by modest frequencies of natural killer (NK), CD4+, or CD8+ T cells, producing low levels of IFN-γ. At 21 days, NKT populations were reduced to a combined 20% of TIL, giving way to increased NK, CD4+, and CD8+ T cells, with increased IFN-γ production. Treatment with CB accelerated this switch. At day 11, CB reduced NKT to less than 20% of all TIL, downregulated TNFα across NKT and CD4+ T cell populations, increased CD4+ and CD8+ TIL frequencies, and significantly upregulated IFN-γ production. Degranulation was largely associated with NK and NKT TIL. Blockade of H-2kb and/or CD1d during ex vivo cytotoxicity assays revealed NKT has limited direct cytotoxicity against parent MC38. However, forced CD1d overexpression in MC38 cells significantly diminished tumor growth, suggesting NKT TIL exerts indirect control over MC38 growth.ConclusionsDespite an indirect benefit of early NKT activity, CB accelerates a switch from TNFα, NKT-driven immune response toward an IFN-γ driven CD4+/CD8+ T cell response in MC38 tumors. These results uncover a novel NKT/T cell switch that may be a key feature of CB response in CD1d+ tumors.

scholarly journals 769 A single dose of intratumoral TransCon™ TLR7/8 agonist monotherapy promoted sustained activation of antigen presenting cells resulting in CD4+ and CD8+ T cell activation and tumor growth inhibition

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A804-A804
Author(s):  
Luis Zuniga ◽  
Karan Uppal ◽  
Kathy Bang ◽  
Enping Hong ◽  
Simran Sabharwal ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Growth Inhibition ◽  
Tumor Antigen ◽  
Tumor Growth Inhibition ◽  
Tlr Agonists ◽  
Syngeneic Mouse ◽  
Antigen Presenting ◽  
Anti Tumor Activity ◽  
Dose Dependent

BackgroundThe use of pattern recognition receptor agonists (PRRAs) such as Toll-like receptor (TLR) agonists is an attractive approach for cancer immunotherapy. TLR agonism elicits anti-tumor activity by activating antigen presenting cells (APCs) to promote a proinflammatory microenvironment and anti-tumor immunity. Local delivery of TLR agonists has shown encouraging preclinical and clinical anti-tumor benefit. However, intratumoral (IT) delivery of naked PRRAs may lead to rapid effusion from the tumor microenvironment, potentially impacting their effectiveness in inducing local inflammation and may promote systemic cytokine release, increasing the risk of adverse effects.MethodsTransConTM TLR7/8 Agonist was designed to address the current limitations of PRRA therapies and IT delivery through sustained and controlled release of resiquimod, a potent TLR7/8 agonist, following IT administration of a hydrogel depot.ResultsA single IT injection of TransCon TLR7/8 Agonist induced potent tumor growth inhibition in a dose-dependent manner in syngeneic mouse CT26 tumors. Following IT TransCon TLR7/8 Agonist treatment, acute and sustained upregulation of cell surface markers indicative of activation of APCs, such as CD54, CD69, and CD86, in the tumor was observed by fluorescence activated flow cytometry (FACs). Additionally, TransCon TLR7/8 Agonist treatment was associated with an increase in the frequency of APCs with an activated phenotype in tumor draining lymph nodes (LNs). Further, a concomitant potentiation in the frequency of activated CD4 and CD8 T cells in tumor draining LNs following IT TransCon TLR7/8 Agonist treatment was observed, as demonstrated by increased expression of Ki67, ICOS, or granzyme B.ConclusionsThese data support that a single IT dose of TransCon TLR7/8 Agonist can mediate robust anti-tumor activity as a monotherapy in the CT26 syngeneic mouse tumor model while promoting local activation of intratumoral APCs. Such activation may promote tumor antigen uptake and migration to tumor-associated lymphoid tissue, as evidenced by an increase in APCs with an activated phenotype in tumor draining LNs following TransCon TLR7/8 Agonist treatment. Activated tumor antigen-bearing APCs can promote the priming and activation of tumor-specific T cells in the tumor-draining LNs. Consistently, a dose-dependent increase in the frequency of T cells with an activated effector phenotype in tumor draining LNs following administration of TransCon TLR7/8 Agonist was observed. These preclinical data further support TransCon TLR7/8 Agonist as a novel and potentially efficacious PRRA therapy. A clinical trial to evaluate safety and efficacy of TransCon TLR7/8 Agonist as monotherapy, and in combination with pembrolizumab, in cancer patients has been initiated (transcendIT-101; NCT04799054).Ethics ApprovalThe animal studies performed described were performed in accordance with the “Guide for the Care and Use of Laboratory Animals: Eighth Edition” and approved by the institutional animal care and use committee (IACUC).

scholarly journals Absence of central tolerance in Aire-deficient mice synergizes with immune-checkpoint inhibition to enhance antitumor responses

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Asiel A. Benitez ◽  
Sara Khalil-Agüero ◽  
Anjali Nandakumar ◽  
Namita T. Gupta ◽  
Wen Zhang ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Checkpoint ◽  
Immune Checkpoint Blockade ◽  
Tumor Rejection ◽  
Checkpoint Blockade ◽  
Cell Repertoire ◽  
Activated T Cells ◽  
Central Tolerance ◽  
Tolerance Breakdown ◽  
Deficient Mice

AbstractThe endogenous anti-tumor responses are limited in part by the absence of tumor-reactive T cells, an inevitable consequence of thymic central tolerance mechanisms ensuring prevention of autoimmunity. Here we show that tumor rejection induced by immune checkpoint blockade is significantly enhanced in Aire-deficient mice, the epitome of central tolerance breakdown. The observed synergy in tumor rejection extended to different tumor models, was accompanied by increased numbers of activated T cells expressing high levels of Gzma, Gzmb, Perforin, Cxcr3, and increased intratumoural levels of Cxcl9 and Cxcl10 compared to wild-type mice. Consistent with Aire’s central role in T cell repertoire selection, single cell TCR sequencing unveiled expansion of several clones with high tumor reactivity. The data suggest that breakdown in central tolerance synergizes with immune checkpoint blockade in enhancing anti-tumor immunity and may serve as a model to unmask novel anti-tumor therapies including anti-tumor TCRs, normally purged during central tolerance.

scholarly journals Angiostatic and chemotactic activities of the CXC chemokine CXCL4L1 (platelet factor-4 variant) are mediated by CXCR3

Blood ◽  
2011 ◽  
Vol 117 (2) ◽  
pp. 480-488 ◽  
Author(s):  
Sofie Struyf ◽  
Laura Salogni ◽  
Marie D. Burdick ◽  
Jo Vandercappellen ◽  
Mieke Gouwy ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer Cells ◽  
Tumor Growth ◽  
Natural Killer ◽  
Platelet Factor 4 ◽  
Vascular Effects ◽  
Activated T Cells ◽  
Platelet Factor ◽  
Killer Cells ◽  
Cxc Chemokine

Abstract We investigated possible cellular receptors for the human CXC chemokine platelet factor-4 variant/CXCL4L1, a potent inhibitor of angiogenesis. We found that CXCL4L1 has lower affinity for heparin and chondroitin sulfate-E than platelet factor-4 (CXCL4) and showed that CXCL10 and CXCL4L1 could displace each other on microvascular endothelial cells. Labeled CXCL4L1 also bound to CXCR3A- and CXCR3B-transfectants and was displaced by CXCL4L1, CXCL4, and CXCL10. The CXCL4L1 anti-angiogenic activity was blocked by anti-CXCR3 antibodies (Abs) in the Matrigel and cornea micropocket assays. CXCL4L1 application in CXCR3−/− or in wild-type mice treated with neutralizing anti-CXCR3 Abs, resulted in reduced inhibitory activity of CXCL4L1 on tumor growth and vascularization of Lewis lung carcinoma. Furthermore, CXCL4L1 and CXCL4 chemoattracted activated T cells, human natural killer cells, and human immature dendritic cells (DCs). Migration of DCs toward CXCL4 and CXCL4L1 was desensitized by preincubation with CXCL10 and CXCL11, inhibited by pertussis toxin, and neutralized by anti-CXCR3 Abs. Chemotaxis of T cells, natural killer cells, and DCs is likely to contribute to the antitumoral action. However, the in vivo data indicate that the angiostatic property of CXCL4L1 is equally important in retarding tumor growth. Thus, both CXCR3A and CXCR3B are implicated in the chemotactic and vascular effects of CXCL4L1.

scholarly journals Two novel human anti-CD25 antibodies with antitumor activity inversely related to their affinity and in vitro activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Deyong Song ◽  
Xiu Liu ◽  
Chuangchuang Dong ◽  
Qiaoping Wang ◽  
Chunjie Sha ◽  
...  
Keyword(s):  
T Cells ◽  
Tumor Growth ◽  
Growth Inhibition ◽  
Treg Cells ◽  
Tumor Growth Inhibition ◽  
In Vitro Activity ◽  
Limited Efficacy ◽  
Cancer Models ◽  
Excellent Candidate

AbstractHigh tumor regulatory T (Treg) cell infiltration is associated with poor prognosis of many cancers. CD25 is highly expressed on tumor Treg cells and is a potential target for Treg deletion. Previously characterized anti-CD25 antibodies appear to have limited efficacy in tumor inhibition. Here we identified two human anti-CD25 antibodies, BA9 and BT942, which did not prevent the activation of IL-2R signaling pathway by IL-2. BT942 had weaker binding and cytotoxic activity to human CD25-expressing cell lines than BA9. But both demonstrated significant tumor growth inhibition in early and late-stage animal cancer models. BT942 resulted in a higher expansion of CD8+ T cells and CD4+ T cells in tumor microenvironment in mouse MC38 model compared to BA9. BT942 also demonstrated significant higher tumor growth inhibition and higher expansion of CD8+ T cells and CD4+ T cells in combination with an anti-PD1 antibody. Pharmacokinetic study of BT942 in cynomolgus monkeys demonstrated a half-life of 206.97 ± 19.03 h. Structural analysis by cryo-EM revealed that BT942 recognizes an epitope on opposite side of the CD25-IL-2 binding site, consistent with no IL-2 signaling blockade in vitro. BT942 appears to be an excellent candidate for cancer immunotherapy.

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