Project description:To investigate that Tubastain A, a HDAC6 inhibitor, has effect on early stage of iTreg differentiation, we treated naïve CD4+ T cells with DMSO (vehicle control) or 10 uM Tubastatin A and cultured the cells under Treg-skewing condition for 1 day. We then performed gene expression profiling analysis using data from RNA-seq of 2 different samples.
Project description:Histone deacetylase 6 (HDAC6) is an epigenetic modifier that is an attractive pharmacological target in cancer. In this work, we show that HDAC6 is elevated in glioblastoma, the most malignant and common brain tumor in adults, and in glioma stem cells. Moreover, we identified a new small-molecule inhibitor of HDAC6, called JOC1, which presents strong sensitivity for HDAC6 inhibition and exerts high cytotoxic activity, alone or in combination with temozolomide. Moreover, it is able to significantly reduce tumor growth in vivo. Transcriptomic analysis of patient derived glioma stem cells revealed an increase in cell differentiation and cell death as well as decrease in cell cycle activity and cell division as relevant cellular pathways whose activities are significantly altered by the treatment with JOC1. In conclusion, our data reveal the efficacy of a novel HDAC6 inhibitor in glioblastoma pre-clinical setting
Project description:Foxp3+ T-regulatory cells (Tregs) are key to immune homeostasis such that their diminished numbers or function can cause autoimmunity and allograft rejection. Foxp3+ Tregs express histone/protein deacetylases (HDACs) that regulate chromatin remodeling, gene expression and protein function. Pan-HDAC inhibitors developed for oncology enhance Treg production and suppression but have limited non-oncologic applications given their broad effects. We show, using HDAC6-deficient mice and WT mice treated with HDAC6-specific inhibitors, that HDAC6 inhibition promotes Treg suppressive activity in models of inflammation and autoimmunity, including multiple forms of experimental colitis and fully MHC-incompatible cardiac allograft rejection. Many of the beneficial effects of HDAC6 targeting are also achieved by inhibition of the HDAC6-regulated protein, HSP90. Hence, selective targeting of a single HDAC isoform, HDAC6, or its downstream target, HSP90, can promote Treg-dependent suppression of autoimmunity and transplant rejection. RNA from three independent samples from magnetically separated CD4+CD25+ Treg of HDAC6 knock out, compared to wild type (C57BL6) control
Project description:Regulatory T cells (Tregs) expressing the transcription factor FOXP3 are crucial mediators of self-tolerance, preventing autoimmune diseases but possibly hampering tumor rejection. Clinical manipulation of Tregs is of great interest, and first- in-man trials of Treg transfer achieved promising outcomes. Yet, the mechanisms governing induced Treg (iTreg) differentiation and the regulation of FOXP3 are incompletely understood. To gain a comprehensive and unbiased molecular understanding of FOXP3 induction, we performed time-series RNA sequencing (RNA-Seq) and proteomics profiling on the same samples during human iTreg differentiation. To enable the broad analysis of universal FOXP3-inducing pathways, we used five differentiation protocols in parallel. Integrative analysis of the transcriptome and proteome confirmed involvement of specific molecular processes, as well as overlap of a novel iTreg subnetwork with known Treg regulators and autoimmunity-associated genes. Importantly, we propose 37 novel molecules putatively involved in iTreg differentiation. Their relevance was validated by: a targeted shRNA screen confirming a functional role in FOXP3 induction; discriminant analyses classifying iTregs accordingly; and comparable expression in an independent novel iTreg RNA-Seq data set. The data generated by this novel approach facilitate understanding the molecular mechanisms underlying iTreg generation as well as the concomitant changes in the transcriptome and proteome. Our results provide a reference map exploitable for future discovery of markers and drug candidates governing control of Tregs, which has important implications for the treatment of cancer, autoimmune and inflammatory diseases.
Project description:Despite the anticancer activity of pan-histone deacetylase (HDAC) inhibitors, their clinical use has been limited due to toxicity. However, the development of more specific inhibitors that selectively inhibit individual HDACs is emerging as a novel and well-tolerated alternative. Here, we present the results of the first clinical trial evaluating the activity of ricolinostat (the leading HDAC6 inhibitor) in breast cancer (BC) patients. We have developed a computational network-based algorithm to evaluate the activity of the HDAC6 protein, based on the enrichment of its transcriptional targets in differentially expressed genes (HDAC6 score). Through preclinical in vitro and in vivo studies, we confirmed that the HDAC6 score can stratify the sensitivity of BC cells to ricolinostat treatment and may thus have value as a predictive biomarker. Moreover, analysis of ~3,000 primary human breast cancers showed that ~30% of them present high HDAC6 scores. Based on these results, we designed a phase Ib clinical trial to evaluate the activity of ricolinostat plus nab-paclitaxel in metastatic BC patients. Study results showed that the two agents can be safely combined, that clinical activity is identified specifically in patients with HR+/HER2- disease, and that the HDAC6 score was predictive of response. Expansion of our analysis to other tumor types identified multiple cohorts enriched in high HDAC6 score samples. These results suggest that the HDAC6 score may provide an effective predictive biomarker of ricolinostat sensitivity in multiple human cancers.
Project description:Induced Treg (iTreg) cells are essential for tolerance and can be used therapeutically, yet their stability in vivo and mechanisms of suppression are unresolved. Here, we used a treatment model of colitis to examine the role of autologous IL-10 in iTreg cell function. Mice treated with IL-10+/+ iTreg cells in combination with IL-10–/– natural Treg (nTreg) cells survived and gained weight, even though iTreg cells were numerically disadvantaged and comprised just ~20% of all Treg cells in treated mice. Notably, ~85% of the transferred iTreg cells lost Foxp3 expression (ex-iTreg) but retained a portion of the iTreg transcriptome which failed to limit their pathogenic potential. The TCR repertoires of iTreg and ex-iTreg cells exhibited almost no overlap, which indicates that the two populations are clonally unrelated and maintained by different selective pressures. These data demonstrate a potent and critical role for iTreg cell produced IL-10 that can supplant the IL-10 produced by nTreg cells and compensate for the inherent instability of the iTreg population. BALB/c Rag1-/- mice were treated with 500,00 WT nTreg cells plus 500,000 WT in-vitro-derived iTreg cells. After 125 days cells were sorted by flow cytometry from spleens and mesenteric lymph nodes from 14 treated mice. EGFP+ Thy1.1+ iTreg cells, EGFP+ Thy1.1– nTreg cells, and EGFP–Thy1.1+ ex-iTreg cells were pooled and used to generate total RNA for each iTreg, nTreg, and ex-iTreg array set, which was labeled and hybridized to Affymetrix 430 2.0 GeneChips in accordance to the manufacturer’s protocol. Two sets of arrays were performed, and the results were averaged. Both iTreg and nTreg array sets were compared to a) naïve CD4+EGFP– Tconv cells from Foxp3EGFP. The subset of probe sets whose expression increased or decreased by twofold or more relative to Tconv cells as a common standard was identified and used for further analysis.
Project description:Foxp3+ T-regulatory cells (Tregs) are key to immune homeostasis such that their diminished numbers or function can cause autoimmunity and allograft rejection. Foxp3+ Tregs express histone/protein deacetylases (HDACs) that regulate chromatin remodeling, gene expression and protein function. Pan-HDAC inhibitors developed for oncology enhance Treg production and suppression but have limited non-oncologic applications given their broad effects. We show, using HDAC6-deficient mice and WT mice treated with HDAC6-specific inhibitors, that HDAC6 inhibition promotes Treg suppressive activity in models of inflammation and autoimmunity, including multiple forms of experimental colitis and fully MHC-incompatible cardiac allograft rejection. Many of the beneficial effects of HDAC6 targeting are also achieved by inhibition of the HDAC6-regulated protein, HSP90. Hence, selective targeting of a single HDAC isoform, HDAC6, or its downstream target, HSP90, can promote Treg-dependent suppression of autoimmunity and transplant rejection.
Project description:Induced Treg (iTreg) cells are essential for tolerance and can be used therapeutically, yet their stability in vivo and mechanisms of suppression are unresolved. Here, we used a treatment model of colitis to examine the role of autologous IL-10 in iTreg cell function. Mice treated with IL-10+/+ iTreg cells in combination with IL-10–/– natural Treg (nTreg) cells survived and gained weight, even though iTreg cells were numerically disadvantaged and comprised just ~20% of all Treg cells in treated mice. Notably, ~85% of the transferred iTreg cells lost Foxp3 expression (ex-iTreg) but retained a portion of the iTreg transcriptome which failed to limit their pathogenic potential. The TCR repertoires of iTreg and ex-iTreg cells exhibited almost no overlap, which indicates that the two populations are clonally unrelated and maintained by different selective pressures. These data demonstrate a potent and critical role for iTreg cell produced IL-10 that can supplant the IL-10 produced by nTreg cells and compensate for the inherent instability of the iTreg population.
Project description:Despite the anticancer activity of pan-histone deacetylase (HDAC) inhibitors, their clinical use has been limited due to toxicity. However, the development of more specific inhibitors that selectively inhibit individual HDACs is emerging as a novel and well-tolerated alternative. Here, we present the results of the first clinical trial evaluating the activity of ricolinostat (the leading HDAC6 inhibitor) in breast cancer (BC) patients. We have developed a computational network-based algorithm to evaluate the activity of the HDAC6 protein, based on the enrichment of its transcriptional targets in differentially expressed genes (HDAC6 score). Through preclinical in vitro and in vivo studies, we confirmed that the HDAC6 score can stratify the sensitivity of BC cells to ricolinostat treatment and may thus have value as a predictive biomarker. Moreover, analysis of ~3,000 primary human breast cancers showed that ~30% of them present high HDAC6 scores. Based on these results, we designed a phase Ib clinical trial to evaluate the activity of ricolinostat plus nab-paclitaxel in metastatic BC patients. Study results showed that the two agents can be safely combined, that clinical activity is identified specifically in patients with HR+/HER2- disease, and that the HDAC6 score was predictive of response. Expansion of our analysis to other tumor types identified multiple cohorts enriched in high HDAC6 score samples. These results suggest that the HDAC6 score may provide an effective predictive biomarker of ricolinostat sensitivity in multiple human cancers.
Project description:Histone deacetylases (HDACs) are crucial regulators of gene expression, DNA synthesis, and cellular processes, making them essential targets in cancer research. HDAC6, specifically, influences protein stability and chromatin dynamics. Despite HDAC6's potential therapeutic value, its exact role in gene regulation and chromatin remodeling needs further clarification. This study examines how HDAC6 inactivation influences lysine acetyltransferase P300 stabilization and subsequent effects on chromatin structure and function in cancer cells. We employed the HDAC6 inhibitor ITF3756, siRNA, or CRISPR/Cas9 gene editing to inactivate HDAC6 in different epigenomic backgrounds. Constantly, this inactivation led to significant changes in chromatin accessibility, particularly increased acetylation of histone H3 lysines 9, 14, and 27 (ATAC-seq and H3K27Ac ChIP-seq analysis). Transcriptomics, proteomics, and gene ontology analysis revealed gene changes in cell proliferation, adhesion, migration, and apoptosis. Significantly, HDAC6 inactivation altered P300 ubiquitination, stabilizing P300 and leading to downregulating genes critical for cancer cell survival. Our study highlights the substantial impact of HDAC6 inactivation on the chromatin landscape of cancer cells and suggests a role for P300 in contributing to the anticancer effects. The stabilization of P300 with HDAC6 inhibition proposes a potential shift in therapeutic focus from HDAC6 itself to its interaction with P300. This finding opens new avenues for developing targeted cancer therapies, improving our understanding of epigenetic mechanisms in cancer cells.