Abstract Combination strategies leveraging chemotherapy and immunotherapy have held the promise as a method to improve benefit to cancer patients. However, most chemotherapies have detrimental effects on immune homeostasis and do not induce immunogenic cell death. The positive phase III trial of pemetrexed/carboplatin with the PD-1 antibody pembrolizumab in NSCLC (Keynote-189) lead to the first chemotherapy/immunotherapy combination ever approved. While this suggests a positive interaction between pemetrexed-based chemotherapy and PD-1 therapy, the underlying mechanism is unknown. Therefore, it is important to understand the role of pemetrexed in modulating antitumor immune response to assure application of this therapy to the appropriate patients. To characterize the effects of pemetrexed on intra-tumor immune response, murine tumor models which were sensitive to pemetrexed and known to be sensitive to PD-L1, were treated with pemetrexed with or without carboplatin, or anti-mouse PD-L1. In MC38 tumors, pemetrexed monotherapy demonstrated a trend towards an increased frequency of intra-tumor leukocytes that was accompanied by immune-related gene expression changes indicative of enhanced T cell infiltration and/or activation. Gene expression induced by pemetrexed was largely unaffected by carboplatin. Treatment of both MC38 and Colon26 tumor cells in vitro with pemetrexed induced release of HMGB1, indicative of immunogenic cell death. Although proliferation of primary human T cells was slightly reduced by pemetrexed, at clinically relevant concentrations, treatment lead to an enhanced T cell activation phenotype, including upregulation of multiple interferon gamma-induced genes, and increased mitochondrial respiration. This correlated with improved antigen specific in vitro cytotoxic activity of OT-1 TCR transgenic CD8 T cells when treated with pemetrexed during priming with OVA peptide. Treatment with pemetrexed and PD-L1 demonstrated a combination benefit compared to either monotherapy in both tumor models. Pathway Analysis of gene expression data revealed that improved antigen presentation, enhanced T cell and cytokine signaling and an engagement of CD4+ T cell-mediated immunity during the combination. This correlated with upregulation of MHC-I & II on monocytes, macrophages and tumor cells, suggesting increased immune priming. Accordingly, treatment with S1P1R antagonist (FTY720, preventing T cell LN egress) after initiation of therapy resulted in a loss of combination efficacy. This data suggests that pemetrexed promotes intra-tumor T cell-mediated immune response through immunogenic tumor cell death and increased activation and metabolic fitness of T cells. The combination of these effects results in enhanced T cell function leading to an improved anti-tumor efficacy in combination with PD-L1 antibody Citation Format: David A. Schaer, Nelusha Amaladas, Zhao Hai Lu, Erik Rasmussen, Andreas Sonyi, Darin Chin, Andrew Capen, Yanxia Li, Catalina Meyer, Bonita Jones, Xiaodong Hong, Shuang Luo, Carmine Carpenito, Kenneth Roth, Alexander Nikolayev, Bo Tan, Manisha Brahmachary, Krishna Chodavarapu, Frank Charles Dorsey, Jason Manro, Thompson Doman, Greg Donoho, David Surguladze, Gerald Hall, Sandaruwan Geeganage, Michael Kalos, Ruslan Novosiadly. The folate pathway inhibitor pemetrexed pleiotropically enhances effects of cancer immunotherapy via immunogenic tumor cell death and T cell-intrinsic mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3945.
Combination strategies leveraging chemotherapy and immunotherapy have held the promise as a method to improve benefit to cancer patients. However, most chemotherapies have detrimental effects on immune homeostasis and do not induce immunogenic cell death. The positive phase III trial of pemetrexed/carboplatin with the PD-1 antibody pembrolizumab in NSCLC (Keynote-189) lead to the first chemotherapy/immunotherapy combination ever approved. While this suggests a positive interaction between pemetrexed-based chemotherapy and PD-1 therapy, the underlying mechanism is unknown. Therefore, it is important to understand the role of pemetrexed in modulating antitumor immune response to assure application of this therapy to the appropriate patients. To characterize the effects of pemetrexed on intra-tumor immune response, murine tumor models which were sensitive to pemetrexed and known to be sensitive to PD-L1, were treated with pemetrexed with or without carboplatin, or anti-mouse PD-L1. In MC38 tumors, pemetrexed monotherapy demonstrated a trend towards an increased frequency of intra-tumor leukocytes that was accompanied by immune-related gene expression changes indicative of enhanced T cell infiltration and/or activation. Gene expression induced by pemetrexed was largely unaffected by carboplatin. Treatment of both MC38 and Colon26 tumor cells in vitro with pemetrexed induced release of HMGB1, indicative of immunogenic cell death. Although proliferation of primary human T cells was slightly reduced by pemetrexed, at clinically relevant concentrations, treatment lead to an enhanced T cell activation phenotype, including upregulation of multiple interferon gamma-induced genes, and increased mitochondrial respiration. This correlated with improved antigen specific in vitro cytotoxic activity of OT-1 TCR transgenic CD8 T cells when treated with pemetrexed during priming with OVA peptide. Treatment with pemetrexed and PD-L1 demonstrated a combination benefit compared to either monotherapy in both tumor models. Pathway Analysis of gene expression data revealed that improved antigen presentation, enhanced T cell and cytokine signaling and an engagement of CD4+ T cell-mediated immunity during the combination. This correlated with upregulation of MHC-I & II on monocytes, macrophages and tumor cells, suggesting increased immune priming. Accordingly, treatment with S1P1R antagonist (FTY720, preventing T cell LN egress) after initiation of therapy resulted in a loss of combination efficacy. This data suggests that pemetrexed promotes intra-tumor T cell-mediated immune response through immunogenic tumor cell death and increased activation and metabolic fitness of T cells. The combination of these effects results in enhanced T cell function leading to an improved anti-tumor efficacy in combination with PD-L1 antibodyCitation Format: David A. Schaer, Nelusha Amaladas, Zhao Hai Lu, Erik Rasmussen, Andreas Sonyi, Darin Chin, Andrew Capen, Yanxia Li, Catalina Meyer, Bonita Jones, Xiaodong Hong, Shuang Luo, Carmine Carpenito, Kenneth Roth, Alexander Nikolayev, Bo Tan, Manisha Brahmachary, Krishna Chodavarapu, Frank Charles Dorsey, Jason Manro, Thompson Doman, Greg Donoho, David Surguladze, Gerald Hall, Sandaruwan Geeganage, Michael Kalos, Ruslan Novosiadly. The folate pathway inhibitor pemetrexed pleiotropically enhances effects of cancer immunotherapy via immunogenic tumor cell death and T cell-intrinsic mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3945.
<p>Figure S1. Efficacy of pemetrexed in Lewis Lung carcinoma model and metabolomic analysis of MC38 tumor bearing mice treated with 50 mg/kg of pemetrexed Figure S2. T cell inflamed phenotype induced by pemetrexed is modestly reduced in tumors upon combination with cisplatin Figure S3. Combination Effects of pemetrexed -/+ anti-PD-L1 in MC38, LLC and Colon26 tumor models Figure S4 (A) Mice bearing Colon26 tumors were treated starting 10 days after tumor implantation with pemetrexed (50 mg/kg, 5 days on, 2 days off, IP) and/or anti-PD-L1 (αPD-L1) (500 ug/mouse, weekly IP), and tumors were isolated after 14 days of treatment and single cell suspensions were subjected to flow cytometry analysis. FACS plots show representative data of intra-tumor CD45+ tumor-infiltrating lymphocyte (TIL) T cell (CD3+) and Myeloid cell (CD11b+) subsets frequencies; and percentage of Ki67+ CD4+ T effector cells based on the gating scheme indicated. (B) Spleens, TDLNs and tumors were isolated and antigen specific T cell responses were measured by IFNγ ELISpot, gp70 Tetramer staining (Tet) and Intracellular cytokine staining. (Left) CD8 T cells isolated from pooled spleens and TDLNs from individual mice were cultured alone (control) with irrelevant BALB/c tumor EMT6 or cognate Colon26 tumor cells overnight and number of IFNγ producing T cells was measured by ELISpot. (Middle) Freshly isolated CD8+ T cells from spleens and TDLNs were assessed for % of gp70 Tet+ cells. (Right) Freshly isolated tumors single cell suspensions were stimulated with PMA/ phorbol myristate acetate (PMA) and ionomycin with monensin for 4 hrs and the % of TNF-alpha positive and gp70 Tet+ CD8 T cells were measured from the Live CD45+, CD3+ T cells by FACS. Figure S5. Concordance between QuantiGene and nCounter gene expression data for in vitro activated T cells treated in the presence or absence of pemetrexed (related to Figure 6F). Supplementary Table 1. Ingenuity pathway analysis (IPA) of MC38 tumors treated with pemetrexed or paclitaxel with or without carboplatin Supplementary Table 2: IPA results for Colon26 experiment in Figure 4 sorted by functional class. Pemetrexed monotherapy in this experiment at this timepoint did not have enough differentially expressed genes to generate IPA results.</p>
288 The PI3 Kinase/AKT pathway plays a critical role in cell survival signaling and the activation of this pathway has been linked to tumorigenesis. Upregulation of AKT (PKB) and PI3 Kinase is seen in many tumor types and the negative regulator of this pathway PTEN is deleted in a number of tumor types. Therefore, this pathway remains an attractive target for cancer drug discovery. Glycogen Synthase Kinase-beta (GSK3b) is characterized to be phosphorylated at its Ser 9 site by AKT. Phosphorylation of GSK3b by AKT results in inactivation of the kinase activity of GSK3b and downstream activation of glycogen synthesis and metabolic events leading to and promoting cell proliferation. Therefore, phosphorylation of GSK3b at the Ser 9 site can be utilized as a pharmacodynamic marker for evaluating the in vivo PK/PD effects of AKT/PI3K inhibitors. We developed a novel in cell ELISA to measure the phosphorylation of GSK3b in U87MG cells. In order to link cellular target inhibition to in vivo target inhibition, we utilized a commercially available sandwich ELISA to measure the in vivo activity of PI3 Kinase/AKT pathway inhibitors quantitating the phosphorylation level of GSK3b in native U87MG glioblastoma cells. We treated these cells and mice bearing U87MG xenografts with the PI3 Kinase inhibitor wortmannin and an Isoquinoline Sulfonamide (IS) AKT inhibitor. The ELISA analysis showed that PI3 Kinase inhibitor Wortmannin and IS AKT inhibitor inhibits GSK3b phosphorylation U87MG cells potently in vitro and in vivo. The inhibition correlates well with the inhibition of phosphorylation of other known AKT substrates such as phospho-Forkhead and phospho-TSC2. In vivo pGSK3b inhibition shows excellent correlation with serum exposure of compound. These results show that phospho-GSK3b can be utilized as a in vitro and in vivo PD marker to develop inhibitors of AKT and PI3 Kinase as potential targeted cancer therapeutic agents.
Abstract Background: Recently, pemetrexed and carboplatin in combination with PD–1 antibody (pembrolizumab) demonstrated markedly improved clinical outcome in NSCLC patients (KEYNOTE–021G trial) suggesting a positive interaction between pemetrexed–based chemotherapy and immunotherapy. However, the role of pemetrexed in modulating antitumor immune response is largely unknown. The objective of this study was to characterize the effects of pemetrexed on intra–tumor immune response in monotherapy and combination with carboplatin or PD–1 pathway blockade in preclinical models. Methods: Mice bearing syngeneic MC38 or Colon26 tumors were treated with pemetrexed with or without carboplatin or anti–mouse PD–L1 antibody (178G7). Immune cell subsets and immune–related changes in mouse tumor tissue and T cells were assessed by flow cytometry and gene expression analysis (Quantigene Plex and nanoString nCounter assays). Effects of pemetrexed on immunogenic cell death in tumor cells and mitochondrial respiration in T cells were evaluated by HMGB1 ELISA and Agilent Seahorse XF analysis, respectively. Results: In MC38 tumors, pemetrexed monotherapy demonstrated a trend towards an increased frequency of intratumoral leukocytes and total and cycling (Ki67+) T cells accompanied by immune–related gene expression changes indicative of enhanced antigen presentation, T cell infiltration and/or activation and down–modulation of the myeloid cell compartment. Immune gene expression signature induced by pemetrexed was largely unaffected by carboplatin. In both MC38 and Colon26 tumor cells, in vitro treatment with pemetrexed induced a robust release of HMGB1 indicative of immunogenic cell death. Proliferation of primary human T cells stimulated with CD3/CD28 was inhibited by pemetrexed in a dose–dependent manner. At clinically relevant concentrations pemetrexed also enhanced T cell activation phenotype exemplified by an increased frequency of CD137+, GITR+ and PD–L1+ T cells as well as upregulation of multiple interferon gamma–induced genes, and increased mitochondrial respiration. In both MC38 and Colon26 models, treatment with pemetrexed and 178G7 demonstrated a combination benefit compared to either monotherapy, and nCounter profiling of Colon26 tumors followed by Ingenuity Pathway Analysis revealed that improved antigen presentation, enhanced T cell and cytokine signaling and an engagement of CD4+ T cell–mediated immunity might underlie this combination effect. Conclusions: Pemetrexed promotes intra–tumor T cell–mediated immune response through immunogenic tumor cell death and increased activation and metabolic fitness of T cells leading to an enhanced anti–tumor efficacy in combination with PD–L1 antibody. Citation Format: Ruslan Novosiadly, David Schaer, Nelusha Amaladas, Erik Rasmussen, Zhao Hai Lu, Andreas Sonyi, Carmine Carpenito, Yanxia Li, Shuang Luo, Andrew Capen, Catalina Meyer, Xiaodong Huang, Jason Manro, Gregory Donoho, Thompson Doman, Gerald Hall, Sandaruwan Geeganage, Michael Kalos. Pemetrexed enhances anti-tumor efficacy of PD1 pathway blockade by promoting intra tumor immune response via immunogenic tumor cell death and T cell intrinsic mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4549.
2560 Phosphoinositide 3-OH kinase (PI3-K) and its downstream target, Akt mediate one of the most important survival signaling pathways in cancer cells. The mechanism by which PI3-K/Akt pathway affects cell survival is through its downstream target proteins such as BAD, Caspase-9, Forkhead transcription factors, IKKα and TSC1/2. Therefore, inhibition of Akt activity is expected to induce apoptotic cell death at multiple levels. In addition, down-regulation of Akt signaling pathway may sensitize cancer cells to cytotoxic oncolytics. There are enormous clinical advantages in exploring this cell survival pathway. This makes Akt among the most validated and attractive targets for the discovery of efficacious therapeutics for the treatment of human cancers. Here we report that isoquinoline sulfonamide-based Akt kinase inhibitors exert potent anti-proliferative effect on U87MG human glioblastoma cells and Jurkat human T-cell leukemia cells. Both cell lines are PTEN-null with constitutively activated Akt. We further demonstrate that these AKT inhibitors induce a robust Caspases activation and rapid phosphatidyl serine (PS) exposure on cell surface, characteristic of cells undergoing rapid apoptosis. Data will also be presented to show that down-regulation of Akt activity either by Akt-specific siRNA or small molecule inhibitors sensitize cancer cells to various oncolytics such as Gemcitabine, Camptothecin and Dexamethasone, as well as TRAIL. We conclude that treatment of U87MG and Jurkat cells with isoquinoline sulfonamide class of Akt inhibitor results in apoptotic cell death. And these results support the notion that synergistic anticancer action can be achieved by combination therapy using Akt inhibitors and conventional cytotoxic cancer therapeutics.
<p>Figure S1. Efficacy of pemetrexed in Lewis Lung carcinoma model and metabolomic analysis of MC38 tumor bearing mice treated with 50 mg/kg of pemetrexed Figure S2. T cell inflamed phenotype induced by pemetrexed is modestly reduced in tumors upon combination with cisplatin Figure S3. Combination Effects of pemetrexed -/+ anti-PD-L1 in MC38, LLC and Colon26 tumor models Figure S4 (A) Mice bearing Colon26 tumors were treated starting 10 days after tumor implantation with pemetrexed (50 mg/kg, 5 days on, 2 days off, IP) and/or anti-PD-L1 (αPD-L1) (500 ug/mouse, weekly IP), and tumors were isolated after 14 days of treatment and single cell suspensions were subjected to flow cytometry analysis. FACS plots show representative data of intra-tumor CD45+ tumor-infiltrating lymphocyte (TIL) T cell (CD3+) and Myeloid cell (CD11b+) subsets frequencies; and percentage of Ki67+ CD4+ T effector cells based on the gating scheme indicated. (B) Spleens, TDLNs and tumors were isolated and antigen specific T cell responses were measured by IFNγ ELISpot, gp70 Tetramer staining (Tet) and Intracellular cytokine staining. (Left) CD8 T cells isolated from pooled spleens and TDLNs from individual mice were cultured alone (control) with irrelevant BALB/c tumor EMT6 or cognate Colon26 tumor cells overnight and number of IFNγ producing T cells was measured by ELISpot. (Middle) Freshly isolated CD8+ T cells from spleens and TDLNs were assessed for % of gp70 Tet+ cells. (Right) Freshly isolated tumors single cell suspensions were stimulated with PMA/ phorbol myristate acetate (PMA) and ionomycin with monensin for 4 hrs and the % of TNF-alpha positive and gp70 Tet+ CD8 T cells were measured from the Live CD45+, CD3+ T cells by FACS. Figure S5. Concordance between QuantiGene and nCounter gene expression data for in vitro activated T cells treated in the presence or absence of pemetrexed (related to Figure 6F). Supplementary Table 1. Ingenuity pathway analysis (IPA) of MC38 tumors treated with pemetrexed or paclitaxel with or without carboplatin Supplementary Table 2: IPA results for Colon26 experiment in Figure 4 sorted by functional class. Pemetrexed monotherapy in this experiment at this timepoint did not have enough differentially expressed genes to generate IPA results.</p>
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