Project description:There is increasing recognition of the prognostic significance of tumor cell major histocompatibility complex (MHC) class II expression in anti-cancer immunity. Relapse of acute myeloid leukemia (AML) following allogeneic stem cell transplantation (alloSCT) has recently been linked to MHC class II silencing in leukemic blasts; however, the regulation of MHC class II expression remains incompletely understood. Utilizing unbiased CRISPR-Cas9 screens, we identify that the C-terminal binding protein (CtBP) complex transcriptionally represses MHC class II pathway genes, while the E3 ubiquitin ligase complex component FBXO11 mediates degradation of CIITA, the principal transcription factor regulating MHC class II expression. Targeting these repressive mechanisms selectively induces MHC class II upregulation across a range of AML cell lines. Functionally, MHC class II+ leukemic blasts stimulate antigen-dependent CD4+ T cell activation and potent anti-tumor immune responses, providing fundamental insights into the graft-versus-leukemia effect. These findings establish the rationale for therapeutic strategies aimed at restoring tumor-specific MHC class II expression to salvage AML relapse post-alloSCT and also potentially to enhance immunotherapy outcomes in non-myeloid malignancies.
Project description:We previously reported that a synthetic Nod1 ligand, FK565, induced coronary arteritis in mice similar to Kawasaki disease. However, the molecular mechanisms underlying this site-specific inflammation have remained elusive. In this study, we found that CD11c+MHC class II+ cells accumulated in the heart of FK565-treated mice prior to arteritis development. We used microarray analysis to detail gene expression of CD11c+MHC class II+ cells. To obtain gene expression profile of CD11c+MHC class II+ cells, we isolated these cells from hearts of FK565-treated mice. Briefly, female mice at 8weeks age were administered 500 μg of FK565 subcutaneously at day 0 and day 3. At day6, murine hearts were removed and digested with collagenase. CD11c+MHC II+ cells were sorted as PI–CD45+Ly6G–NK1.1–CD11b+CD11c+MHC II+ using FACS Aria cell sorter (BD Biosciences). Sorted cells were subjected to RNA preparation. Two independent replicates from ten mice were made.
Project description:There is increasing recognition of the prognostic significance of tumor cell major histocompatibility complex (MHC) class II expression in anti-cancer immunity. Relapse of acute myeloid leukemia (AML) following allogeneic stem cell transplantation (alloSCT) has recently been linked to MHC class II silencing in leukemic blasts; however, the regulation of MHC class II expression remains incompletely understood. Utilizing unbiased CRISPR-Cas9 screens, we identify that the C-terminal binding protein (CtBP) complex transcriptionally represses MHC class II pathway genes, while the E3 ubiquitin ligase complex component FBXO11 mediates degradation of CIITA, the principal transcription factor regulating MHC class II expression. Targeting these repressive mechanisms selectively induces MHC class II upregulation across a range of AML cell lines. Functionally, MHC class II+ leukemic blasts stimulate antigen-dependent CD4+ T cell activation and potent anti-tumor immune responses, providing fundamental insights into the graft-versus-leukemia effect. These findings establish the rationale for therapeutic strategies aimed at restoring tumor-specific MHC class II expression to salvage AML relapse post-alloSCT and also potentially to enhance immunotherapy outcomes in non-myeloid malignancies.
Project description:There is increasing recognition of the prognostic significance of tumor cell major histocompatibility complex (MHC) class II expression in anti-cancer immunity. Relapse of acute myeloid leukemia (AML) following allogeneic stem cell transplantation (alloSCT) has recently been linked to MHC class II silencing in leukemic blasts; however, the regulation of MHC class II expression remains incompletely understood. Utilizing unbiased CRISPR-Cas9 screens, we identify that the C-terminal binding protein (CtBP) complex transcriptionally represses MHC class II pathway genes, while the E3 ubiquitin ligase complex component FBXO11 mediates degradation of CIITA, the principal transcription factor regulating MHC class II expression. Targeting these repressive mechanisms selectively induces MHC class II upregulation across a range of AML cell lines. Functionally, MHC class II+ leukemic blasts stimulate antigen-dependent CD4+ T cell activation and potent anti-tumor immune responses, providing fundamental insights into the graft-versus-leukemia effect. These findings establish the rationale for therapeutic strategies aimed at restoring tumor-specific MHC class II expression to salvage AML relapse post-alloSCT and also potentially to enhance immunotherapy outcomes in non-myeloid malignancies.
Project description:There is increasing recognition of the prognostic significance of tumor cell major histocompatibility complex (MHC) class II expression in anti-cancer immunity. Relapse of acute myeloid leukemia (AML) following allogeneic stem cell transplantation (alloSCT) has recently been linked to MHC class II silencing in leukemic blasts; however, the regulation of MHC class II expression remains incompletely understood. Utilizing unbiased CRISPR-Cas9 screens, we identify that the C-terminal binding protein (CtBP) complex transcriptionally represses MHC class II pathway genes, while the E3 ubiquitin ligase complex component FBXO11 mediates degradation of CIITA, the principal transcription factor regulating MHC class II expression. Targeting these repressive mechanisms selectively induces MHC class II upregulation across a range of AML cell lines. Functionally, MHC class II+ leukemic blasts stimulate antigen-dependent CD4+ T cell activation and potent anti-tumor immune responses, providing fundamental insights into the graft-versus-leukemia effect. These findings establish the rationale for therapeutic strategies aimed at restoring tumor-specific MHC class II expression to salvage AML relapse post-alloSCT and also potentially to enhance immunotherapy outcomes in non-myeloid malignancies.
Project description:We previously reported that a synthetic Nod1 ligand, FK565, induced coronary arteritis in mice similar to Kawasaki disease. However, the molecular mechanisms underlying this site-specific inflammation have remained elusive. In this study, we found that CD11c+MHC class II+ cells accumulated in the heart of FK565-treated mice prior to arteritis development. We used microarray analysis to detail gene expression of CD11c+MHC class II+ cells.
Project description:Impaired expression of MHC class I constitutes a major mechanism of immune evasion of cancers, leading to poor prognosis and resistance to checkpoint blockade therapies. Existing drugs for MHC class I have limited applicability due to severe side effects. Here we show a novel approach of robust and specific induction of MHC class I by targeting an MHC class I transactivator (CITA), NLRC5, using a CRISPR/Cas9 based gene-specific targeted demethylaion (TDM) system and targeted demethylation and activation (TDMa) system. The TDMa system specifically recruits a demethylating enzyme and transcriptional activators, providing efficient demethylation and transactivation of the NLRC5 promoter. TDMa in mouse and human cancer cells induced MHC class I antigen presentation and accelerated CD8+ T cell activation with tumor suppression effects both in vitro and in vivo. Moreover, enhanced immunogenicity by NLRC5 TDMa boosted efficacy of anti-PD1 therapy. Therefore, NLRC5 targeting by the TDMa system confers an attractive therapeutic approach against cancer.