scholarly journals miR-124-3p enhances dendritic cell-mediated anti-tumor immunity by targeting CYLD/4-1BBL pathway

Author(s):  
Yujie Lei ◽  
Wujin Li ◽  
Yangming Chen ◽  
Kai Chen ◽  
Yunchao Huang ◽  
...  

Abstract Objective: To investigate miR-124-3p regulation of DC-mediated immune response via CYLD/4-1BBL pathway, and the inhibitory effect of miR-124-3p on lung cancer.Methods: DCs were cultured and amplified in vitro, and then transfected with miR-124-3p mimic, miR-124-3P inhibitor, or siRNA CYLD. Double luciferase reporter genes were used to detect the target relationship between miR-124-3p and CYLD. qRT-PCR and western blotting were used to detect the expression levels of CYLD and 4-1BBL. Flow cytometry was used to assess the proliferation rate of CD4+ T cells co-cultured with untransfected DCs and those transfected with miR-124-3p mimic or miR-124-3p inhibitor. C57BL/6 tumor bearing mice, implanted with LL/2 lung adenocarcinoma cells, were administered DCs transfected with the miR-124-3p mimic or untransfected DCs. The tumor size and weight of mice were then measured. Results: miR-124-3p and CYLD3’UTR contained target-binding site, and overexpression of miR-124-3p enhanced the expression of CYLD and 4-1BBL. CD4+ T cells co-cultured with miR-124-3p mimic-transfected DCs showed significantly increased proliferation. In tumor-bearing mice, tumor inhibition rate was 73.5%, and tumor volume and weight were significantly decreased after the administration of DCs containing the miR-124-3p mimic.Conclusions: The expression of CYLD was regulated by miR-124-3p, which, in turn, increased the expression of 4-1BBL. miR-124-3p regulated DCs function via CYLD/4-1BBL cascade. miR-124-3p plays important roles in DCs-induced T cells, thereby enhancing anti-tumor immunity.

2021 ◽  
Author(s):  
Wujin Li ◽  
Yujie Lei ◽  
Yangming Chen ◽  
Kai Chen ◽  
Yunchao Huang ◽  
...  

Abstract Background: MicroRNAs play important roles in dendritic cell (DCs)-mediated immunity, but their specific functions in lung cancer remain unclear.Objective: To investigate miR-124-3p regulation of DC-mediated immune response via CYLD/4-1BBL pathway, and the inhibitory effect of miR-124-3p on lung cancer.Methods: DCs were cultured and amplified in vitro, and then transfected with miR-124-3p mimic, miR-124-3P inhibitor, or siRNA CYLD. Double luciferase reporter genes were used to detect the target relationship between miR-124-3p and CYLD. qRT-PCR and western blotting were used to detect the expression levels of CYLD and 4-1BBL. Flow cytometry was used to assess the proliferation rate of CD4+ T cells co-cultured with untransfected DCs and those transfected with miR-124-3p mimic or miR-124-3p inhibitor. C57BL/6 tumor bearing mice, implanted with LL/2 lung adenocarcinoma cells, were administered DCs transfected with the miR-124-3p mimic or untransfected DCs. The tumor size and weight of mice were then measured. Results: miR-124-3p and CYLD3’UTR contained target-binding site, and overexpression of miR-124-3p enhanced the expression of CYLD and 4-1BBL. CD4+ T cells co-cultured with miR-124-3p mimic-transfected DCs showed significantly increased proliferation. In tumor-bearing mice, tumor inhibition rate was 73.5%, and tumor volume and weight were significantly decreased after the administration of DCs containing the miR-124-3p mimic.Conclusions: The expression of CYLD was regulated by miR-124-3p, which, in turn, increased the expression of 4-1BBL. miR-124-3p regulated DCs function via CYLD/4-1BBL cascade. miR-124-3p plays important roles in DCs-induced T cells, thereby enhancing anti-tumor immunity.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A717-A717
Author(s):  
Abigail Overacre-Delgoffe ◽  
Anthony Cillo ◽  
Hannah Bumgarner ◽  
Ansen Burr ◽  
Justin Tometich ◽  
...  

BackgroundColorectal cancer remains one of the most common and deadliest cancers worldwide and effective therapies are lacking. While immunotherapy has revolutionized treatment for many cancers, the overwhelming majority of colorectal cancer patients are non-responsive and the 5-year survival rate for advanced disease is <20%. Immunotherapeutic response has been associated with select members of the microbiome in melanoma; however, the potential benefit in colorectal cancer and the underlying mechanisms remain unclear. We sought to determine how specific members of the intestinal microbiome affect anti-tumor immunity in colorectal cancer (CRC) in hopes of discovering novel treatments and revealing potential hurdles to current therapeutic response in CRC patients.MethodsWe utilized a carcinogen-induced mouse model of CRC and colonized half of the tumor-bearing mice with Helicobacter hepaticus (Hhep) 7 weeks post AOM. Tumor number was assessed 12 weeks post AOM. We isolated lymphocytes from the lamina propria, colonic epithelium, mesenteric lymph nodes, and tumor(s) to track the spatial and transcriptional Hhep-specific and endogenous immune responses during tumor progression through 5’ single cell RNAseq, flow cytometry, and immunofluorescence. In addition, we utilized 16S sequencing and FISH to track Hhep colonization, location within the colon, and its impact on the surrounding microbiome.ResultsWe have found that rational modification of the microbiome of colon tumor-bearing mice through addition of a single bacteria, Hhep, led to tumor control or clearance and a significant survival advantage. Colonization led to the expansion of the lymphatic network and development of numerous peri- or intra-tumoral tertiary lymphoid structures (TLS) composed of Hhep-specific CD4 T follicular helper cells (TFH) as well as the bacteria itself. This led to an overall ‘heating’ of the tumor, wherein we saw an increase of CD4 T cell infiltration to the tumor core as well as an increase in CD103+ type 1 DC (cDC1) recruitment through increased chemokines such as CCL5 and XCL1. Hhep-specific TFH were both necessary and sufficient to drive TLS formation, increased immune invasion, and anti-tumor immunity.ConclusionsWe have shown that addition of a single bacteria, Hhep, leads to a reduction in CRC tumor burden or clearance through lymphatic expansion, TLS formation, and remodeling of the tumor microenvironment, and that Hhep-specific T cells are required for tumor control. These studies suggest that rational modification of the microbiome and microbiome-specific T cells can positively impact anti-tumor immunity and may represent a unique immunotherapeutic target to turn resistant tumors into responsive tumors.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A126-A126
Author(s):  
John Goulding ◽  
Mochtar Pribadi ◽  
Robert Blum ◽  
Wen-I Yeh ◽  
Yijia Pan ◽  
...  

BackgroundMHC class I related proteins A (MICA) and B (MICB) are induced by cellular stress and transformation, and their expression has been reported for many cancer types. NKG2D, an activating receptor expressed on natural killer (NK) and T cells, targets the membrane-distal domains of MICA/B, activating a potent cytotoxic response. However, advanced cancer cells frequently evade immune cell recognition by proteolytic shedding of the α1 and α2 domains of MICA/B, which can significantly reduce NKG2D function and the cytolytic activity.MethodsRecent publications have shown that therapeutic antibodies targeting the membrane-proximal α3 domain inhibited MICA/B shedding, resulting in a substantial increase in the cell surface density of MICA/B and restoration of immune cell-mediated tumor immunity.1 We have developed a novel chimeric antigen receptor (CAR) targeting the conserved α3 domain of MICA/B (CAR-MICA/B). Additionally, utilizing our proprietary induced pluripotent stem cell (iPSC) product platform, we have developed multiplexed engineered, iPSC-derived CAR-MICA/B NK (iNK) cells for off-the-shelf cancer immunotherapy.ResultsA screen of CAR spacer and ScFv orientations in primary T cells delineated MICA-specific in vitro activation and cytotoxicity as well as in vivo tumor control against MICA+ cancer cells. The novel CAR-MICA/B design was used to compare efficacy against NKG2D CAR T cells, an alternative MICA/B targeting strategy. CAR-MICA/B T cells showed superior cytotoxicity against melanoma, breast cancer, renal cell carcinoma, and lung cancer lines in vitro compared to primary NKG2D CAR T cells (p<0.01). Additionally, using an in vivo xenograft metastasis model, CAR-MICA/B T cells eliminated A2058 human melanoma metastases in the majority of the mice treated. In contrast, NKG2D CAR T cells were unable to control tumor growth or metastases. To translate CAR-MICA/B functionality into an off-the-shelf cancer immunotherapy, CAR-MICA/B was introduced into a clonal master engineered iPSC line to derive a multiplexed engineered, CAR-MICA/B iNK cell product candidate. Using a panel of tumor cell lines expressing MICA/B, CAR-MICA/B iNK cells displayed MICA specificity, resulting in enhanced cytokine production, degranulation, and cytotoxicity. Furthermore, in vivo NK cell cytotoxicity was evaluated using the B16-F10 melanoma cell line, engineered to express MICA. In this model, CAR-MICA/B iNK cells significantly reduced liver and lung metastases, compared to untreated controls, by 93% and 87% respectively.ConclusionsOngoing work is focused on extending these preclinical studies to further support the clinical translation of an off-the-shelf, CAR-MICA/B iNK cell cancer immunotherapy with the potential to overcome solid tumor escape from NKG2D-mediated mechanisms of recognition and killing.ReferenceFerrari de Andrade L, Tay RE, Pan D, Luoma AM, Ito Y, Badrinath S, Tsoucas D, Franz B, May KF Jr, Harvey CJ, Kobold S, Pyrdol JW, Yoon C, Yuan GC, Hodi FS, Dranoff G, Wucherpfennig KW. Antibody-mediated inhibition of MICA and MICB shedding promotes NK cell-driven tumor immunity. Science 2018 Mar 30;359(6383):1537–1542.


2020 ◽  
Vol 15 (1) ◽  
pp. 871-883
Author(s):  
Jinshan Zhang ◽  
Dan Rao ◽  
Haibo Ma ◽  
Defeng Kong ◽  
Xiaoming Xu ◽  
...  

AbstractBackgroundOsteosarcoma is a common primary malignant bone cancer. Long noncoding RNA small nucleolar RNA host gene 15 (SNHG15) has been reported to play an oncogenic role in many cancers. Nevertheless, the role of SNHG15 in the doxorubicin (DXR) resistance of osteosarcoma cells has not been fully addressed.MethodsCell Counting Kit-8 assay was conducted to measure the half-maximal inhibitory concentration value of DXR in osteosarcoma cells. Western blotting was carried out to examine the levels of autophagy-related proteins and GDNF family receptor alpha-1 (GFRA1). Quantitative reverse transcription-polymerase chain reaction was performed to determine the levels of SNHG15, miR-381-3p, and GFRA1. The proliferation of osteosarcoma cells was measured by MTT assay. The binding sites between miR-381-3p and SNHG15 or GFRA1 were predicted by Starbase bioinformatics software, and the interaction was confirmed by dual-luciferase reporter assay. Murine xenograft model was established to validate the function of SNHG15 in vivo.ResultsAutophagy inhibitor 3-methyladenine sensitized DXR-resistant osteosarcoma cell lines to DXR. SNHG15 was upregulated in DXR-resistant osteosarcoma tissues and cell lines. SNHG15 knockdown inhibited the proliferation, DXR resistance, and autophagy of osteosarcoma cells. MiR-381-3p was a direct target of SNHG15, and GFRA1 bound to miR-381-3p in osteosarcoma cells. SNHG15 contributed to DXR resistance through the miR-381-3p/GFRA1 axis in vitro. SNHG15 depletion contributed to the inhibitory effect of DXR on osteosarcoma tumor growth through the miR-381-3p/GFRA1 axis in vivo.ConclusionsSNHG15 enhanced the DXR resistance of osteosarcoma cells through elevating the autophagy via targeting the miR-381-3p/GFRA1 axis. Restoration of miR-381-3p expression might be an underlying therapeutic strategy to overcome the DXR resistance of osteosarcoma.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A172-A172
Author(s):  
Guillermo Rangel Rivera ◽  
Guillermo Rangel RIvera ◽  
Connor Dwyer ◽  
Dimitrios Arhontoulis ◽  
Hannah Knochelmann ◽  
...  

BackgroundDurable responses have been observed with adoptive T cell therapy (ACT) in some patients. However, current protocols used to expand T cells often exhibit suboptimal tumor control. Failure in these therapies has been attributed to premature differentiation and impaired metabolism of the infused T cells. Previous work done in our lab showed that reduced PI3Kδ signaling improved ACT. Because PI3Kγ and PI3Kδ have critical regulatory roles in T cell differentiation and function, we tested whether inhibiting PI3Kγ could recapitulate or synergize PI3Kδ blockade.MethodsTo test this, we primed melanoma specific CD8+ pmel-1 T cells, which are specific to the glycoprotein 100 epitope, in the presence of PI3Kγ (IPI-459), PI3Kδ (CAL101 or TGR-1202) or PI3Kγ/δ (IPI-145) inhibitors following antigen stimulation with hgp100, and then infused them into 5Gy total body irradiated B16F10 tumor bearing mice. We characterized the phenotype of the transferred product by flow cytometry and then assessed their tumor control by measuring the tumor area every other day with clippers. For metabolic assays we utilized the 2-NBDG glucose uptake dye and the real time energy flux analysis by seahorse.ResultsSole inhibition of PI3Kδ or PI3Kγ in vitro promoted greater tumor immunity and survival compared to dual inhibition. To understand how PI3Kδ or PI3Kγ blockade improved T cell therapy, we assessed their phenotype. CAL101 treatment produced more CD62LhiCD44lo T cells compared to IPI-459, while TGR-1202 enriched mostly CD62LhiCD44hi T cells. Because decreased T cell differentiation is associated with mitochondrial metabolism, we focused on CAL101 treated T cells to study their metabolism. We found that CAL101 decreased glucose uptake and increased mitochondrial respiration in vitro, indicating augmented mitochondrial function.ConclusionsThese findings indicate that blocking PI3Kδ is sufficient to mediate lasting tumor immunity of adoptively transferred T cells by preventing premature differentiation and improving mitochondrial fitness. Our data suggest that addition of CAL101 to ACT expansion protocols could greatly improve T cell therapies for solid tumors by preventing T cell differentiation and improving mitochondrial function.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Kuijie Liu ◽  
Hua Zhao ◽  
Hongliang Yao ◽  
Sanlin Lei ◽  
Zhendong Lei ◽  
...  

MicroRNAs are a class of small, noncoding RNAs that function as critical regulators of gene expression by targeting mRNAs for translational repression or degradation. In this study, we demonstrate that expression of microRNA-124 (miR-124) is significantly downregulated in colorectal cancer tissues and cell lines, compared to the matched adjacent tissues. We identified and confirmed inhibitor of apoptosis-stimulating protein of p53 (iASPP) as a novel, direct target of miR-124 using target prediction algorithms and luciferase reporter gene assays. Overexpression of miR-124 suppressed iASPP protein expression, upregulated expression of the downstream signaling molecule nuclear factor-kappa B (NF-κB), and attenuated cell viability, proliferation, and colony formation in SW480 and HT-29 colorectal cancer cells in vitro. Forced overexpression ofiASPPpartly rescued the inhibitory effect of miR-124 on SW480 and HT29 cell proliferation. Taken together, these findings shed light on the role and mechanism of action of miR-124, indicate that the miR-124/iASPP axis can regulate the proliferation of colorectal cancer cells, and suggest that miR-124 may serve as a potential therapeutic target for colorectal cancer.


Blood ◽  
2021 ◽  
Author(s):  
Billy Michael Chelliah Jebaraj ◽  
Annika Müller ◽  
Rashmi Priyadharshini Dheenadayalan ◽  
Sascha Endres ◽  
Philipp M. Roessner ◽  
...  

Covalent Bruton tyrosine kinase (BTK) inhibitors such as ibrutinib have proven to be highly beneficial in the treatment of chronic lymphocytic leukemia (CLL). Interestingly, the off-target inhibition of IL-2-inducible T-cell kinase (ITK) by ibrutinib may also play a role in modulating the tumor microenvironment, potentially enhancing the treatment benefit. However, resistance to covalently binding BTK inhibitors can develop by a mutation in cysteine 481 of BTK (C481S), which prevents the irreversible binding of the drugs. In the present study we performed pre-clinical characterization of vecabrutinib, a next generation non-covalent BTK inhibitor, with ITK inhibitory properties similar to those of ibrutinib. Unlike ibrutinib and other covalent BTK inhibitors, vecabrutinib showed retention of the inhibitory effect on C481S BTK mutants in vitro, similar to that of wildtype BTK. In the murine Eµ-TCL1 adoptive transfer model, vecabrutinib reduced tumor burden and significantly improved survival. Vecabrutinib treatment led to a decrease in CD8+ effector and memory T-cell populations, while the naïve populations were increased. Of importance, vecabrutinib treatment significantly reduced frequency of regulatory CD4+ T-cells (Tregs) in vivo. Unlike ibrutinib, vecabrutinib treatment showed minimal adverse impact on activation and proliferation of isolated T-cells. Lastly, combination treatment of vecabrutinib with venetoclax was found to augment treatment efficacy, significantly improve survival and lead to favourable reprogramming of the microenvironment in the murine Eµ-TCL1 model. Thus, non-covalent BTK/ITK inhibitors such as vecabrutinib may be efficacious in C481S BTK mutant CLL, while preserving the T-cell immunomodulatory function of ibrutinib.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A679-A679
Author(s):  
Ying Zheng ◽  
Andriana Lebid ◽  
Andrew Pardoll ◽  
Juan Fu ◽  
Chirag Patel ◽  
...  

BackgroundActivins, members of the transforming growth factor-ß (TGF-ß) superfamily, were isolated and identified in endocrine system, and have been widely studied in endocrine-related cancers,1 2 but not substantially in the context of immune system and endocrine-unrelated cancers.3–5 It has been reported that upon binding to the receptors, activins cause the intracellular recruitment and phosphorylation of smad proteins, which mediate the expression of Foxp3.6–9 Therefore, we hypothesized that the blockade of the interaction of activins and their receptors will inhibit the activins-mediated Foxp3 induction in CD4+ T cells, thus modify the immune suppressive tumor microenvironment and achieve the goal of cancer immunotherapy.MethodsELISA (enzyme-linked immunosorbent assay) has been performed to determine the plasma level of Activin A in tumor-bearing mice and cancer patients. In vitro iTreg (induced regulatory T cells) differentiation has been done to naïve CD4+ cells isolated from wild type mice in the presence or absence of Activin A, and the percentage of Foxp3+ cells was demonstrated by flow cytometric analysis. qRT-PCR analysis has been conducted to determine the mRNA level of activin receptor isotypes in the immune subpopulations sorted from Foxp3-YFP mice. In the end, in vivo subcutaneous transplanted tumor studies have been done to evaluate the anti-tumor therapeutic effects of activin-receptor 1c blockade.ResultsWe show here that tumor-bearing mice had elevated Activin A levels, which correlated directly with tumor burden. Likewise, cancer patients had elevated plasma Activin A compared to healthy controls. Importantly, our in vitro studies suggested that Activin A promoted differentiation of conventional CD4+ cells into Foxp3-expressing induced Tregs, especially when TGF-ß was limited. Database and qRT-PCR analysis of sorted major immune cell subsets in mice revealed that activin receptor 1C (Acvr1c) was uniquely expressed on Tregs and was highly upregulated during iTreg differentiation. Mice deficient in Acvr1c were more resistant to cancer progression compared to wild type mice. This phenotype correlated with reduced expression of the FoxP3 transcription factor in CD4+ cells. Similar phenomena were observed when we treated the mice with anti-Acvr1c antibody after tumor inoculation. This anti-tumor therapeutic effect was more significant when anti-Acvr1c antibody was administrated in combination with anti-PD-1 antibody.ConclusionsBlocking Activin A signaling through its receptor 1c is a promising and disease-specific strategy for preventing the accumulation of immunosuppressive iTregs in cancer. Hence it represents a potential candidate for cancer immunotherapy.AcknowledgementsThis research is supported by the Bloomberg-Kimmel Institute (Immunometabolism Program & Immune Modulation Program), the Melanoma Research Alliance, the NIH (RO1AI099300, RO1AI089830, and R01AI137046), and The DoD (PC130767).ReferencesRisbridger GP, Schmitt JF, Robertson DM. Activins and inhibins in endocrine and other tumors. Endocr Rev 2001;22(6):836–858.Cui X, et al. Perspectives of small molecule inhibitors of activin receptor-like kinase in anti-tumor treatment and stem cell differentiation (Review). Mol Med Rep 2019;19(6):5053–5062.Michael IP, et al. ALK7 signaling manifests a homeostatic tissue barrier that is abrogated during tumorigenesis and metastasis. Dev Cell 2019;49(3):409–424.Wu B, et al. The TGF-ß superfamily cytokine Activin-A is induced during autoimmune neuroinflammation and drives pathogenic Th17 cell differentiation. Immunity 2021;54(2):308–323.Antsiferova M, et al. Activin promotes skin carcinogenesis by attraction and reprogramming of macrophages. MBO Mol Med 2017;9(1):27–45.Tsuchida K, et al. Activin isoforms signal through type I receptor serine/threonine kinase ALK7. Mol Cell Endocrinol 2004;220(1–2):59–65.Khalil AM, et al. Differential binding activity of TGF-ß family proteins to select TGF-ß receptors. J Pharmacol Exp Ther 2016;358(3):423–430.Huber S, et al. Activin a promotes the TGF-beta-induced conversion of CD4+CD25- T cells into Foxp3+ induced regulatory T cells. J Immunol 2009;182(8):4633–4640.Iizuka-Koga M, et al. Induction and maintenance of regulatory T cells by transcription factors and epigenetic modifications. J Autoimmun 2017;83:113–121.Ethics ApprovalAll animal experiments were performed under protocols approved by the Johns Hopkins University Institutional Animal Care and Use Committee (IACUC).


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A348-A348
Author(s):  
Jessie Wang ◽  
Kaixia Lian ◽  
Jia Zheng ◽  
Chenpan Nie ◽  
Annie An ◽  
...  

BackgroundThe development of immuno-oncology (I/O) therapeutics has revolutionized the cancer treatment landscape. Despite this achievement, the mechanism behind limited responses is poorly understood. Tumor immune evasion has been reported to arise through the loss of tumor necrosis factor (TNF) signaling, interferon-γ (IFN-γ) signaling, and antigen presentation pathways, which are crucial to CD8+ T cell-mediated killing. Syngeneic mouse models have been widely used as they have an intact immune system, are easily accessible, and have a vast array of historical data for comparison. However, limited syngeneic models respond to immune checkpoint inhibitors, possibly due to low intrinsic immunogenicity. The expression of ovalbumin (OVA) has previously shown to sufficiently alter the susceptibility of syngeneic tumors to host T cell-mediated responses. In this study, the newly developed OVA-expressing MC38 syngeneic line was characterized for tumor immunity, checkpoint blockade response and response durability.MethodsMurine colon cancer MC38 cells were transduced by lentiviral vector with chicken OVA coding cDNA. A single clone was selected, and OVA expression was confirmed by western blot. The MC38-OVA cells were subcutaneously implanted into immunocompetent mice to evaluate the tumorigenicity and in vivo response to anti-PD-1 antibody treatment. Blood was collected 2 days post final dose of anti-PD-1 treatment for phenotypic analysis by FACS. Spleen and tumor draining lymph nodes were collected at termination for FACS analysis of IFN-γ+ T cells and OVA specific CD8+ T cells. Adoptive transfer was evaluated by challenge studies in both MC38-OVA and MC38 tumor-bearing mice with T cells derived from MC38-OVA mice, anti-PD-1 cured mice and OT-I mice. In vitro killing assays were performed to evaluate the function of adoptive CD3+ T cells transfer.ResultsOVA-expressing MC38 presented complete regression under anti-PD-1 treatment in vivo. T cell expansion was observed after anti-PD-1 treatment in peripheral blood with increased IFN-γ+ T cells in both tumor-draining lymph nodes and spleen. Additionally, anti-PD-1 cured mice generated robust tumor specific memory T cell, which successfully inhibited MC38-OVA and MC38 tumor growth following adoptive transfer. CD3+ T cells from MC38-OVA-bearing mice and OT-I mice showed anti-tumor immunity in vivo. In vitro killing assay demonstrated increased immunity.ConclusionsSyngeneic mouse tumor models are preferred preclinical models for I/O research, despite limited intrinsic immunogenicity. OVA expression in syngeneic tumors largely increased T cell-mediated immunity to enhance antigen-specific T cell responses during tumorigenesis, providing novel immunogenic models for preclinical immunotherapy evaluation.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A880-A880
Author(s):  
Abigail Overacre-Delgoffe ◽  
Hannah Bumgarner ◽  
Anthony Cillo ◽  
Ansen Burr ◽  
Justin Tometich ◽  
...  

BackgroundColorectal cancer (CRC) is one of the most common and deadly cancers in the US, and the survival rate for advanced cases is poor. While immunotherapy has revolutionized cancer treatment, CRC remains largely unresponsive, with only ~6% of patients responding to anti-PD1. Specific microbiome signatures are associated with anti-PD1 response in melanoma patients; however, the underlying mechanism remains unclear. While the microbiome in cancer patients has been extensively studied, the endogenous immune response to these microbes and the subsequent effects on cancer immunity remain unstudied. Most microbes reside within the gut, and bacteria that adhere to the intestinal epithelium can stimulate bacteria-specific immune responses. Therefore, we hypothesized that the microbiome, especially adherent, immunogenic bacteria, may support anti-tumor immunity through activation of local microbiota-specific T cells.MethodsUsing a carcinogen-induced mouse model of CRC, we sought to determine the impact of microbiome modulation on the anti-tumor immune response. We colonized tumor-bearing mice with Helicobacter hepaticus (Hhep) and assessed tumor burden, survival, and immune infiltration. Lymphocytes were isolated from the tumor and surrounding tissue when tumors were terminal (12 weeks). We utilized TCR transgenic mice and MHC class II tetramers to track the spatial and transcriptional Hhep-specific T cell response through 5’ single cell RNAseq, flow cytometry, and spectral immunofluorescence.ResultsHhep colonization in tumor-bearing mice led to decreased tumor burden and significantly improved survival. Interestingly, colonization induced activation of Hhep-specific T follicular helper cells (TFHs) that supported formation of mature peri- or intra-tumoral tertiary lymphoid structures (TLS). The presence of TLS led to increased infiltration of cytotoxic lymphocytes (T and NK cells) within the tumor core. Surprisingly, the anti-tumor response was dependent on CD4+ T and B cells but not CD8+ T cells. Using TFH KO mice, we found that Hhep-specific CD4+ T cells were both necessary and sufficient to drive TLS maturation and anti-tumor immunity.ConclusionsHere, we demonstrate that addition of a single bacterial species after tumor formation leads to a reduction in CRC tumor burden and increased survival through TLS maturation. This microbiome-dependent remodeling of the tumor microenvironment is driven by Hhep-specific TFH cells that are both necessary and sufficient for tumor control, demonstrating for the first time that microbiota-specific T cells contribute to anti-tumor immunity. Overall, these findings suggest that microbiome modulation and the subsequent microbiota-specific CD4+ T cell response may represent a new variety of immunotherapies for cancers that remain resistant to checkpoint blockade.


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