scholarly journals 678 Addition of a single bacteria facilitates anti-tumor immunity and long-term survival in colorectal cancer

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A717-A717
Author(s):  
Abigail Overacre-Delgoffe ◽  
Anthony Cillo ◽  
Hannah Bumgarner ◽  
Ansen Burr ◽  
Justin Tometich ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Tumor Immunity ◽  
Tumor Burden ◽  
Intestinal Microbiome ◽  
Tumor Control ◽  
Mesenteric Lymph Nodes ◽  
Term Survival ◽  
16S Sequencing ◽  
Tumor Bearing

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.

scholarly journals 839 Microbiota-specific T follicular helper cells drive tertiary lymphoid structure formation and anti-tumor immunity in colorectal cancer

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A880-A880
Author(s):  
Abigail Overacre-Delgoffe ◽  
Hannah Bumgarner ◽  
Anthony Cillo ◽  
Ansen Burr ◽  
Justin Tometich ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Immune Response ◽  
T Cells ◽  
Tumor Immunity ◽  
Cell Response ◽  
Tumor Burden ◽  
T Cell Response ◽  
Tumor Bearing ◽  
Follicular Helper ◽  
Necessary And Sufficient

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.

253 Anti-TIGIT antibodies require enhanced FcγR co-engagement for optimal T and NK cell-dependent anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A275-A275
Author(s):  
Rebecca Ward ◽  
Elena Paltrinieri ◽  
Marilyn Marques ◽  
Priyadarshini Iyer ◽  
Sylvia Dietrich ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Microenvironment ◽  
Tumor Immunity ◽  
Cell Activation ◽  
Nk Cell ◽  
Tumor Control ◽  
Tumor Bearing ◽  
Anti Tumor Activity ◽  
Ct26 Tumor ◽  
Dependent Mechanism

BackgroundT-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an important negative regulator of the immune response to cancer that contributes to resistance/relapse to anti-PD-1 therapy.1 In clinical trials, anti-human (h) TIGIT antibodies have shown promising activity in combination with anti-PD-1/PD-L1 antibodies for the treatment of various solid tumors.2 However, the optimal format for anti-TIGIT antibodies remains controversial. Here we describe a novel Fcγ receptor (FcγR)-dependent mechanism of action that is critical for enhancing T and NK cell anti-tumor immunity, and, further informs on the optimal design of anti-TIGIT antibodies.MethodsWe investigated a panel of Fc-silent, Fc-competent, and Fc-engineered anti-mouse (m) TIGIT antibody variants in syngeneic murine CT26 tumor-bearing or B16F10 pseudo-metastases models. To further elucidate the relative contribution of T and NK cells in controlling tumor growth, we assessed the activity of Fc-engineered anti-TIGIT antibodies in NK cell-depleted or T cell-deficient (Nu-Foxn1nu) CT26 tumor-bearing mice. Immune-related pharmacodynamic changes in the tumor microenvironment were assessed by flow cytometry. We further validated these findings in primary human T and NK cell activation assays using Fc-engineered anti-human TIGIT antibodies.ResultsThe Fc-engineered anti-mTIGIT antibody, which demonstrates enhanced binding to mouse FcγRIV, was the only variant to deliver single agent anti-tumor activity. The Fc-enhanced variant outperformed the Fc-competent variant while the Fc-inert variant had no anti-tumor activity. Tumor control by anti-mTIGIT antibodies was not dependent on Treg depletion, but rather on increased frequency of CD8+ T cells and activated NK cells (Ki67, IFNγ, CD107a and TRAIL) in the tumor microenvironment. Concordant with observations in the mouse, Fc-engineered anti-hTIGIT antibodies with improved binding to FcγRIIIA demonstrate superior T and NK cell activation in PBMC-based assays compared to a standard hIgG1 variant. Notably, superior activity of the Fc-engineered anti-hTIGIT antibody was observed from PBMC donors that express either high or low affinity FcγRIIIA. Blockade of FcγRIIIA or depletion of CD14+ and CD56+ cells reduced the functional activity of the Fc-enhanced anti-TIGIT antibody, confirming the requirement for FcγR co-engagement to maximize T cell responses.ConclusionsOur data demonstrate the importance of FcγR co-engagement by anti-TIGIT antibodies to promote immune activation and tumor control. First generation anti-TIGIT antibodies are not optimally designed to co-engage all FcγRIIIA variants. However, Fc-enhanced anti-TIGIT antibodies unlock a novel FcγR-dependent mechanism of action to enhance T and NK cell-dependent anti-tumor immunity and further improve therapeutic outcomes.ReferencesJohnston RJ, et al., The immunoreceptor TIGIT regulates antitumor and antiviral CD8(+) T cell effector function. Cancer Cell 2014; 26:923–37.Rodriguez-Abreu D, et al., Primary analysis of a randomized, double-blind, phase II study of the anti-TIGIT antibody tiragolumab (tira) plus atezolizumab (atezo) versus placebo plus atezo as first-line (1L) treatment in patients with PD-L1-selected NSCLC (CITYSCAPE). Journal of Clinical Oncology 2020; 38:15_suppl, 9503–9503.

158 Inhibition of PI3Kδ improves tumor specific T cell immunity and metabolic fitness

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A172-A172
Author(s):  
Guillermo Rangel Rivera ◽  
Guillermo Rangel RIvera ◽  
Connor Dwyer ◽  
Dimitrios Arhontoulis ◽  
Hannah Knochelmann ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Differentiation ◽  
T Cell ◽  
Cell Therapy ◽  
Tumor Immunity ◽  
Mitochondrial Function ◽  
T Cell Differentiation ◽  
Tumor Control ◽  
T Cell Therapy

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.

Therapeutic effect of local Interleukin-15 with radiotherapy in breast cancer.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 158-158
Author(s):  
Elena Garcia Martinez ◽  
Karsten A Pilones ◽  
Joseph Aryankalayil ◽  
Silvia Formenti ◽  
Sandra Demaria
Keyword(s):  
Breast Cancer ◽  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Therapeutic Effect ◽  
Tumor Immunity ◽  
Tumor Infiltrating Lymphocytes ◽  
Tumor Control ◽  
Complete Regression ◽  
Growth And Survival

158 Background: Interleukin (IL)-15 is a key regulator of T cell homeostasis with activity in cancer and a favorable toxicity profile compared to IL-2. IL-15 stimulates the proliferation and effector differentiation of CD8+T cells, and the proliferation and activation of natural killer (NK) cells. We observed IL-15 upregulation by gene arrays in radiotherapy (RT)-treated TSA mouse breast cancer, suggesting that it may play a role in RT-induced anti-tumor immunity. However, the upregulation was modest prompting us to test the hypothesis that administration of IL-15 may enhance in situ vaccination by RT. Methods: BALB/c mice with established poorly immunogenic TSA tumors were sham-treated, treated with tumor-targeted RT (8GyX3 days), IL-15 given peri-tumorally (2 ug/mouse/day for 10 days) starting on the first day of RT, and RT+IL-15, and monitored for tumor growth and survival. Tumor infiltrating lymphocytes (TIL) were analyzed by flow cytometry and immunostaining. In some experiments, Batf3-/-mice were used as tumor recipient. Results: IL-15 by itself was ineffective, but it significantly increased tumor control by RT (p=0.0007, RT versus RT+IL-15) leading to complete responses in 50% of the mice, most of them durable. Analysis of TILs showed significantly increased NK cells (CD45+ CD3- DX5+) in tumors treated with RT+IL-15 (p<0.0004 versus sham-treated; p<0.02 versus RT). NK cells were also more activated as indicated by expression of CD122 and CD137. Depletion of NK cells completely abrogated the therapeutic effect of the combination, while CD8 T cell depletion reduced tumor control and rate of complete regression. Interestingly, Batf3-/- mice, which lack CD103+ DCs, showed reduced response to RT+IL-15 compared to WT mice. Conclusions: Data suggest that local IL-15 with RT is an effective strategy to induce anti-tumor immunity to poorly immunogenic breast cancer. NK cells are critical mediators of the response, and may act by both killing tumor cells and promoting priming of CD8 T cells. Experiments are ongoing to determine the mechanisms of durable complete responses. <footer>Acknowledgments: IL-15 was provided by NCI BRB. Garcia-Martinez E was supported by GEICAM grant.</footer>

Experimental treatment of colorectal cancer in mice with human T cells electroporated with NKG2D RNA CAR

Immunotherapy ◽  
2020 ◽  
Author(s):  
Zhendong Li ◽  
Zhixia Chi ◽  
Wei-Xia Ang ◽  
Can Chen ◽  
Johan CK Tay ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Peritoneal Metastasis ◽  
First Generation ◽  
Experimental Treatment ◽  
Tumor Burden ◽  
Antigen Receptors ◽  
Immunodeficient Mice ◽  
Human T Cells ◽  
End Stage

Aim: Peritoneal metastasis is often present in end-stage neoplastic diseases, including recurrent colorectal cancer and is associated with decreased overall survival. Novel methods are needed. Materials & methods: We constructed first-, second- and third-generation chimeric antigen receptors (CARs) specific for NKG2D ligands and modified human T cells with mRNA electroporation. Results: NKG2D CAR expression was detectable for at least 6 days postelectroporation and mediated efficient cytotoxicity against NKG2DL+ tumor cells, but not NKG2DL-cells. Multiple infusions of the first-generation CAR-T cells into immunodeficient mice bearing established peritoneal colorectal xenografts led to significantly reduced tumor burden. Conclusion: mRNA CAR is an economical way to test new CARs and potentiates controlling on-target/off-tumor toxicity and cytokine storms. The use of NKG2D RNA CARs to treat colorectal peritoneal metastasis warrants further investigation.

Targeting inflammatory monocytes in human metastatic colorectal cancer.

2017 ◽  
Vol 35 (4_suppl) ◽  
pp. 605-605 ◽  
Author(s):  
Julie G. Grossman ◽  
Timothy M. Nywening ◽  
Brian Belt ◽  
Michael Ahlers ◽  
William G. Hawkins ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
T Cell ◽  
Murine Model ◽  
Normal Liver ◽  
Tumor Burden ◽  
Effector T Cells ◽  
Facs Analysis ◽  
Inflammatory Monocytes ◽  
Folfox Chemotherapy

605 Background: Colorectal cancer (CRC) is the most common gastrointestinal malignancy. 60% of CRC patients are diagnosed with metastatic CRC (mCRC) and the 5-year survival is < 20%. CCR2+ inflammatory monocytes (IM) are recruited from the bone marrow to the tumor microenvironment by the CCL2/CCR2 chemokine axis. At the tumor, they become tumor associated macrophages (TAM) and play a crucial role in promoting tumor progression, metastasis, and chemoresistance. While the importance of IM has been shown in other malignancies, little is known about their role in mCRC. Methods: Flow cytometry was performed on human and murine PBMCs, adjacent normal tissue, and tumors. Qualitative RT-PCR, ELISA, and confocal microscopy were performed for CCL2 expression. T-cell suppression assays were performed using CD14+ IM isolated from patient PBMCs and liver metastasis (LM). A murine model of CRC LM was created by hemispleen injection of luciferase-labelled MC38 CRC cells. Mice were treated with a CCR2 inhibitor and/or FOLFOX. Results: Prior to liver resection, mCRC patients have a higher percentage of IM in the peripheral blood compared to healthy donors (p < 0.0001), and on multivariate analysis elevated monocytes were prognostic of poor survival. We also found higher levels of CCL2 in the serum of mCRC patients (p < 0.01). Additionally, there was increased expression of CCL2 in LM compared to uninvolved tissue (p < 0.01), with the production of CCL2 localized to mCRC cells. FACS analysis showed CCR2+ TAM were elevated in LM compared to adjacent normal liver (p < 0.05) with a paucity of effector T-cells. CD14+ TAMs isolated from mCRC inhibited T-cell proliferation, illustrating the immune suppressive phenotype of these cells. In a murine model of CRC LM, treating mice with a CCR2 inhibitor alone or in combination with FOLFOX chemotherapy resulted in decreased tumor burden. FACS analysis of treated tumors showed increased effector T-cells in mice treated with CCR2 inhibitor. Conclusions: IM are involved in the progression of mCRC. Targeting these immunosuppressive cells with a CCR2 inhibitor decreases tumor burden in a murine model. This represents a potential novel treatment for mCRC.

scholarly journals T-cell-mediated suppression of anti-tumor immunity. An explanation for progressive growth of an immunogenic tumor.

1980 ◽  
Vol 151 (1) ◽  
pp. 69-80 ◽  
Author(s):  
M J Berendt ◽  
R J North
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Immunity ◽  
Tumor Regression ◽  
Immunocompetent Host ◽  
Suppressor T Cells ◽  
Immunogenic Tumor ◽  
Tumor Bearing ◽  
Concomitant Immunity ◽  
Progressive Growth

The results of this paper are consistent with the hypothesis that progressive growth of the Meth A fibrosarcoma evokes the generation of a T-cell-mediated mechanism of immunosuppression that prevents this highly immunogenic tumor from being rejected by its immunocompetent host. It was shown that it is possible to cause the regression of large, established Meth A tumors by intravenous infusion of tumor-sensitized T cells from immune donors, but only if the tumors are growing in T-cell-deficient recipients. It was also shown that the adoptive T-cell-mediated regression of tumors in such recipients can be prevented by prior infusion of splenic T cells from T-cell-intact, tumor-bearing donors. The results leave little doubt that the presence of suppressor T cells in T-cell-intact, tumor-bearing mice is responsible for the loss of an earlier generated state of concomitant immunity, and for the inability of intravenously infused, sensitized T cells to cause tumor regression. Because the presence of suppressor T cells generated in response to the Meth A did not suppress the capacity of Meth A-bearing mice to generate and express immunity against a tumor allograft, it is obvious that they were not in a state of generalized immunosuppression.

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

2021 ◽  
Author(s):  
Wujin Li ◽  
Yujie Lei ◽  
Yangming Chen ◽  
Kai Chen ◽  
Yunchao Huang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
T Cells ◽  
Dendritic Cell ◽  
Tumor Immunity ◽  
Inhibitory Effect ◽  
Luciferase Reporter ◽  
Tumor Bearing ◽  
Adenocarcinoma Cells ◽  
Target Binding

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.

scholarly journals An in silico exploration of combining Interleukin-12 with Oxaliplatin to treat liver-metastatic colorectal cancer

2019 ◽  
Author(s):  
Qing Wang ◽  
Zhijun Wang ◽  
Yan Wu ◽  
David J Klinke
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Regulatory T Cells ◽  
Combination Therapy ◽  
Metastatic Colorectal Cancer ◽  
In Silico ◽  
Interleukin 12 ◽  
Tumor Control ◽  
Multi Scale ◽  
Chemotherapy Agent

AbstractBackgroundCombining anti-cancer therapies with orthogonal modes of action, such as direct cytotoxicity and immunostimulatory, hold promise for expanding clinical benefit to patients with metastatic disease. For instance, a chemotherapy agent Oxaliplatin (OXP) in combination with Interleukin-12 (IL-12) can eliminate pre-existing liver metastatic colorectal cancer and protect from relapse in a murine model. However, the underlying dynamics associated with the targeted biology and the combinatorial space consisting of possible dosage and timing of each therapy present challenges for optimizing treatment regimens. To address some of these challenges, we developed a predictive simulation platform for optimizing dose and timing of the combination therapy involving Mifepristone-induced IL-12 and chemotherapy agent OXP.MethodsA multi-scale mathematical model comprised of impulsive ordinary differential equations was developed to describe the interaction between the immune system and tumor cells in response to the combined IL-12 and OXP therapy. An ensemble of model parameters were calibrated to published experimental data using a genetic algorithm and used represent three different phenotypes: responders, partial-responders, and non-responders.ResultsThe multi-scale model captures tumor growth patterns of the three phenotypic responses observed in mice in response to the combination therapy against a tumor re-challenge and was used to explore changing the dose and timing of the mixed immune-chemotherapy on tumor growth subjected to a tumor re-challenge in mice. An increased ratio of CD8+ T effectors to regulatory T cells during and after treatment was key to improve tumor control in the responder cohort. Sensitivity analysis indicates that combined OXP and IL-12 therapy worked more efficiently in responders by increased priming of T cells, enhanced CD8+ T cell-mediated killing, and functional inhibition of regulatory T cells. In a virtual cohort that mimics non-responders and partial-responders, simulations show that an increased dose of OXP alone would improve the response. In addition, enhanced IL-12 expression alone or an increased number of treatment cycles of the mixed immune-chemotherapy can barely improve tumor control for non-responders and partial responders.ConclusionsOverall, this study illustrates how mechanistic models can be used for in silico screening of the optimal therapeutic dose and timing in combined cancer treatment strategies.

A pilot study of AMP-224—a PD-1 inhibitor—in combination with stereotactic body radiation therapy (SBRT) in patients with metastatic colorectal cancer.

2015 ◽  
Vol 33 (3_suppl) ◽  
pp. TPS788-TPS788 ◽  
Author(s):  
Austin G. Duffy ◽  
Oxana V. Makarova-Rusher ◽  
Suzanne Fioravanti ◽  
Melissa Walker ◽  
Aradhana Venkatesan ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
T Cells ◽  
Radiation Therapy ◽  
Pilot Study ◽  
Metastatic Colorectal Cancer ◽  
Tumor Immunity ◽  
Stereotactic Body Radiation Therapy ◽  
Cytotoxic T Cells ◽  
Stereotactic Body Radiation ◽  
Activated T Cell

TPS788 Background: AMP-224, a B7-DC Fc fusion protein, binds to PD-1, an inhibitory receptor that is present on the cell surface of exhausted, activated, effector, and memory T cells. AMP-224 has a unique mechanism of action in that it binds specifically to PD-1HI T cells (chronically stimulated / exhausted T cells) but not to PD-1LOcells which represent the normal activated T cell population. Several preclinical studies have documented an increase in peripheral antitumor immunity following radiation, a phenomenon known as the “abscopal effect”. Tumor PD-L1 expression has also been shown to be induced by radiation, which can suppress the anti-tumor immune response. Inhibition of PD-1/PDL-1 axis has been shown to improve anti-tumor immunity by blocking the tumor-mediated suppression of cytotoxic T cells. The aim of the study is to evaluate whether the anti-tumor immunity of anti-PD1 therapy (with AMP-224) can be enhanced by radiation therapy. Methods: Patients with histologically confirmed metastatic colorectal cancer to liver are being enrolled to this pilot study. The objectives are to determine the safety, tolerability and feasibility of AMP-224 in combination with stereotactic body radiation therapy (SBRT) to metastatic hepatic metastasis in patients with advanced colorectal cancer. Select eligibility are as follows: at least 1 measurable metastatic hepatic lesion by RECIST 1.1 criteria and amenable to SBRT. Patient must have progressed on or been intolerant of at least one prior oxaliplatin- and/or irinotecan-containing regimen and have metastatic lesions that are not amenable to curative resection; ECOG ≤ 1; Life expectancy of greater than 3 months. Acceptable organ and bone marrow function. No active or prior documented autoimmune or inflammatory disorders. Clinical trial information: awaited.

Sign in / Sign up

Export Citation Format

Share Document