The essential clathrin adaptor protein complex-2 is tumor suppressive specifically in vivo
Ontology highlight
ABSTRACT: The microenvironment is a rich source of new cancer targets. While whole-genome CRISPR/Cas9 screens have identified vulnerabilities in cultured cells, it is a challenge to use this approach in tumors to interrogate the microenvironment. To this end, we screened a panel of pancreatic cancer lines grown in culture versus as tumors with a phosphatidylinositol metabolism CRISPR/Cas9 library. This revealed the Adaptor Protein complex-2 (AP2) of clathrin-mediated endocytosis behaves as common essential in culture but tumor suppressive in vivo. These polar-opposite phenotypes were attributed to different microenvironments. In culture, AP2 loss reduces endocytosis of transferrin and iron import. In tumors, alternative iron transport pathways allow pro-tumor signaling to manifest. In the most sensitive case, AP2 loss reprograms the plasma membrane proteome, retaining integrins on the surface leading to downregulation of the tumor-suppressor PTEN. Analysis of human tumors suggests a similar tumor suppressive activity. AP2 may foreshadow other proteins unique to the tumor-microenvironment.
Project description:The microenvironment is a rich source of new cancer targets. While whole-genome CRISPR/Cas9 screens have identified vulnerabilities in cultured cells, it is a challenge to use this approach in tumors to interrogate the microenvironment. To this end, we screened a panel of pancreatic cancer lines grown in culture versus as tumors with a phosphatidylinositol metabolism CRISPR/Cas9 library. This revealed the Adaptor Protein complex-2 (AP2) of clathrin-mediated endocytosis behaves as common essential in culture but tumor suppressive in vivo. These polar-opposite phenotypes were attributed to different microenvironments. In culture, AP2 loss reduces endocytosis of transferrin and iron import. In tumors, alternative iron transport pathways allow pro-tumor signaling to manifest. In the most sensitive case, AP2 loss reprograms the plasma membrane proteome, retaining integrins on the surface leading to downregulation of the tumor-suppressor PTEN. Analysis of human tumors suggests a similar tumor suppressive activity. AP2 may foreshadow other proteins unique to the tumor-microenvironment.
Project description:We established a direct in vivo CRISPR/Cas9 gene editing methodology that allowed us to assess the immune-modulatory capabilities of 573 putative cancer genes associated with altered activity in mouse model of lung cancer. Using mouse models of of KrasG12D- and BrafV600E-driven lung cancer, we identified Serpinb9 as our top suppressive and Adam2 as our top enhancing gene. RNA seq analysis from tumors overexpressing Adam2 revealed that Adam2’s oncogenic function is dependent on modulating the tumor immune microenvironment by restraining productive type I and type II interferon responses as well as cytokine signaling, reducing presentation of tumor associated antigen, and modulating surface expression of several immunoregulatory receptors within Kras-driven lung tumors. Adam2 overexpression also led to reduction in expression of immune checkpoint inhibitors such as PD-L1, Lag3, Tigit, and Tim3.This less exhausted tumor microenvironment further induced enhanced cytotoxic efficacy against Adam2 overexpressing lung tumors, in vitro and in vivo. Together, our study highlights the power of integrating cancer genomic with in vivo CRISPR/Cas9 screens to uncover how cancer-associated genetic alterations control responses to immunotherapies.
Project description:Functional genomic screen in 2D cell culture is limited in identifying therapeutic targets that modulates tumor-microenvironment interaction. Through comparison of targeted CRISPR-Cas9 screens in 2D cell culture and cell line derived xenografts of lung cancer A549, we identified MEN1 as the top hit that confers differential essentialities in vitro and in vivo. Knockout of MEN1 in multiple solid cancer types does not impact cell proliferation in vitro, but significantly promotes and inhibits tumor growth in immunodeficient and immunocompetent mice, respectively. Mechanistically, knockout of MEN1 leads to redistribution of its interaction partner MLL1, a histone methyltransferase, to repetitive genomic regions that produce double stranded RNA. This resulted in MARV and cGAS-STING dependent activation of viral mimicry response, which induces tumor promoting neutrophil and tumor suppressing CD8+ T cell infiltrations in immunodeficient and immunocompetent mice, respectively. Consistently, multiple immune cell infiltrations are negatively correlated with MEN1 abundance and positively correlated with that of MLL1 in patient tumors of a broad range of cancer types. Pharmacological inhibition of MEN1-MLL1 interaction reduces tumor growth in CD8+ T cell dependent manner, and synergizes with anti-PD-L1 treatment. These findings reveal tumor microenvironment dependent oncogenic and tumor suppressive function of MEN1 and provide rationale for therapeutic targeting of MEN1 alone or in combination with immunotherapy in multiple solid cancer types.
Project description:In this study, we used a targeted CRISPR/Cas9 screen to identify genes that determine growth of A549 cells in vivo and in vitro. Functional genomic screens in 2D cell culture are of limited use for identifying therapeutic targets that modulate tumor cell-microenvironment cell interactions. By comparing targeted CRISPR-Cas9 screens in 2D culture of A549 lung cancer cells versus xenografts derived from the same cell line, we identified MEN1 as the top hit that confers differential effects in vitro and in vivo. Knockout of MEN1 in multiple solid cancer types does not impact cell proliferation in vitro, but significantly promotes or inhibits tumor growth in immunodeficient or immunocompetent mice, respectively. Mechanistically, knockout of MEN1 leads to increased chromatin interaction of its interaction partner MLL1 (KMT2A), a histone methyltransferase, to repetitive genomic regions, where it activates expression of double-stranded RNA. This results in MARV and cGAS-STING dependent activation of viral mimicry response, which induces infiltration of neutrophils and CD8+ T cells in immunodeficient and immunocompetent mice respectively. Consistently, multiple immune cell infiltrations are negatively correlated with MEN1 abundance and positively correlated with that of MLL1 in patient tumors of a broad range of cancer types. Pharmacological inhibition of MEN1-MLL interaction reduces tumor growth in CD8+ T cell dependent manner, with enhanced activity in combination with anti-PD-1 treatment. These findings reveal tumor microenvironment dependent oncogenic and tumor suppressive functions of MEN1 and provide rationale for therapeutic targeting of MEN1 alone or in combination with immunotherapy in multiple solid cancer types.
Project description:Since PRSS35 only exhibited tumor suppressive effects in mice, but not in the cultured cells, we speculated that some factors in the microenvironment are affected by PRSS35. To explore this possibility, we performed SILAC proteomic analysis in conjunction with RNA sequencing to identify secreted proteins that decreased in accumulation, but not in transcription level, in the culture medium of PRSS35 overexpressing PLC cells.
Project description:The microenvironment of solid tumors such as breast cancer is heterogeneous and complex, containing different types of cell, including cancer stem cells and immune cells. We previously reported the immunoregulatory behavior of the human immune cell in a solid tumor microenvironment-like culture under serum starvation stress for 96 h. Here, we examined the effect of this culture-derived solution on breast cancer development in rats.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and it’s co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.
Project description:In melanoma, immune cell infiltration into the tumor is associated with better patient outcomes and response to immunotherapy. T cell non-inflamed tumors (‘cold tumors’) are associated with tumor cell intrinsic Wnt/β-catenin activation, and are resistant to anti-PD-1 alone or in combination with anti-CTLA-4 therapy. Reversal of the ‘cold tumor’ phenotype and identifying new effective immunotherapies are challenges in melanoma. In a well-established preclinical melanoma model driven by β-catenin, we found that immune checkpoint molecule B7-H3 confers a suppressive tumor microenvironment by modulating antiviral signals and matricellular proteins. Its inhibition primes the microenvironment, and together with blockade of the macrophage checkpoint CD47, but not with anti-PD-1, results in synergistic anti-tumor responses. This study brings B7-H3 to the forefront as inducing a suppressive microenvironment when overexpressed, and it’s co-targeting with CD47 as a novel combination of immune checkpoint inhibitors in melanoma that calls for testing in clinical trials.