Project description:HDAC8, a member of class I HDACs, plays a pivotal role in cell cycle regulation by deacetylating the cohesin subunit SMC3. While cyclins and CDKs are well-established cell cycle regulators, our knowledge of other regulators remains limited. Here we reveal the acetylation of K202 in HDAC8 as a key cell cycle regulator responsive to stress. K202 acetylation in HDAC8, primarily catalyzed by Tip60, restricts HDAC8 activity, leading to increased SMC3 acetylation and cell cycle arrest. Furthermore, cells expressing the mutant from of HDAC8 mimicking K202 acetylation display significant alterations in gene expression, potentially linked to changes in 3D genome structure, including enhanced chromatid loop interactions. K202 acetylation impairs cell cycle progression by disrupting the expression of cell cycle-related genes and sister chromatid cohesion, resulting in G2/M phase arrest. These findings indicate the reversible acetylation of HDAC8 as a cell cycle regulator, expanding our understanding of stress-responsive cell cycle dynamics.
Project description:HDAC8, a member of class I HDACs, plays a pivotal role in cell cycle regulation by deacetylating the cohesin subunit SMC3. While cyclins and CDKs are well-established cell cycle regulators, our knowledge of other regulators remains limited. Here we reveal the acetylation of K202 in HDAC8 as a key cell cycle regulator responsive to stress. K202 acetylation in HDAC8, primarily catalyzed by Tip60, restricts HDAC8 activity, leading to increased SMC3 acetylation and cell cycle arrest. Furthermore, cells expressing the mutant form of HDAC8 mimicking K202 acetylation display significant alterations in gene expression, potentially linked to changes in 3D genome structure, including enhanced chromatid loop interactions. K202 acetylation impairs cell cycle progression by disrupting the expression of cell cycle-related genes and sister chromatid cohesion, resulting in G2/M phase arrest. These findings indicate the reversible acetylation of HDAC8 as a cell cycle regulator, expanding our understanding of stress-responsive cell cycle dynamics.
Project description:HDAC8, a member of class I HDACs, plays a pivotal role in cell cycle regulation by deacetylating the cohesin subunit SMC3. While cyclins and CDKs are well-established cell cycle regulators, our knowledge of other regulators remains limited. Here we reveal acetylated K202 in HDAC8 as a key cell cycle regulator responsive to stress. K202 acetylation in HDAC8, primarily catalyzed by Tip60, negatively modulates HDAC8 activity, leading to increased SMC3 acetylation and cell cycle arrest. Furthermore, cells mimicking K202 acetylation display significant alterations in gene expression, potentially linked to changes in 3D genome structure, including enhanced chromatid loop interactions. K202 acetylation negatively impacts cell cycle progression by disrupting the expression of cell cycle-related genes and sister chromatid cohesion, resulting in G2/M phase arrest. These findings illuminate the reversible acetylation of HDAC8 as a novel cell cycle regulator, expanding our understanding of stress-responsive cell cycle dynamics.
Project description:Cohesin structures the genome through the formation of chromatin loops and by holding together the sister chromatids from S-phase until mitosis. The acetylation of cohesin’s SMC3 subunit is a dynamic process that involves the acetyltransferase ESCO1 and deacetylase HDAC8. Here we show that this cohesin acetylation cycle controls the 3D genome. ESCO1 restricts the length of chromatin loops and architectural stripes, while HDAC8 rather promotes the extension of such loops and stripes. This role in controlling loop length turns out to be distinct from the canonical role of cohesin acetylation that protects against WAPL-mediated DNA release. We reveal that acetylation rather controls cohesin’s interaction with PDS5A to restrict chromatin loop length. Our data supports a model in which this PDS5A-bound state acts as a brake that enables the pausing and restart of loop enlargement. The cohesin acetylation cycle hereby provides punctuation in the process of genome folding.
Project description:Cohesin structures the genome through the formation of chromatin loops and by holding together the sister chromatids from S-phase until mitosis. The acetylation of cohesin’s SMC3 subunit is a dynamic process that involves the acetyltransferase ESCO1 and deacetylase HDAC8. Here we show that this cohesin acetylation cycle controls the 3D genome. ESCO1 restricts the length of chromatin loops and architectural stripes, while HDAC8 rather promotes the extension of such loops and stripes. This role in controlling loop length turns out to be distinct from the canonical role of cohesin acetylation that protects against WAPL-mediated DNA release. Using a genome-wide haploid genetic screen we reveal that acetylation rather controls cohesin’s interaction with PDS5A to restrict chromatin loop length. Our data supports a model in which this PDS5A-bound state acts as a brake that enables the pausing and restart of loop enlargement. The cohesin acetylation cycle hereby provides punctuation in the process of genome folding.
Project description:Cohesin structures the genome through the formation of chromatin loops and by holding together the sister chromatids. The acetylation of cohesin’s SMC3 subunit is a dynamic process that involves the acetyltransferase ESCO1 and deacetylase HDAC8. Here we show that this cohesin acetylation cycle controls the 3D genome. ESCO1 restricts the length of chromatin loops and architectural stripes, while HDAC8 promotes the extension of such loops and stripes. This role in controlling loop length turns out to be distinct from the canonical role of cohesin acetylation that protects against WAPL-mediated DNA release. We reveal that acetylation rather controls cohesin’s interaction with PDS5A to restrict chromatin loop length. Our data supports a model in which this PDS5A-bound state acts as a brake that enables the pausing and restart of loop enlargement. The cohesin acetylation cycle hereby provides punctuation in the process of genome folding.
Project description:Melanoma cells are highly plastic and have the ability to switch to a dedifferentiated, invasive phenotype in response to multiple stimuli. Here, we show that exposure of melanoma cell lines and patient specimens to multiple stresses including BRAF-MEK inhibitor therapy, hypoxia and UV-irradiation leads to an increase in histone deacetylase 8 (HDAC8) expression/activity, and in turn, the adoption of a drug-resistant, invasive phenotype. Systems level analyses using mass spectrometry-based phosphoproteomics implicated HDAC8 in the regulation of MAPK and AP-1 signaling pathways. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in in vivo xenograft models. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase (RTK) activation leading to Ras/CRAF/MEK/ERK signaling. Although HDACs primarily function at the histone level, they also regulate signaling through the modulation of non-histone substrates. In line with this, HDAC8 introduction decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine residue 273 reduced the transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition through increased RTK expression and enhanced MAPK pathway activity. In vivo xenograft studies confirmed the key role of HDAC8 in therapeutic adaptation, with both non-selective and HDAC8-specific inhibitors enhancing the durability of response to BRAF inhibitor therapy. Our studies demonstrate that HDAC8-specific inhibitors could represent an excellent strategy to limit the adaptation of melanoma cells to multiple stresses and therapeutic interventions, including BRAF-MEK inhibitor combinations.
Project description:Melanoma cells are highly plastic and have the ability to switch to a dedifferentiated, invasive phenotype in response to multiple stimuli. Here, we show that exposure of melanoma cell lines and patient specimens to multiple stresses including BRAF-MEK inhibitor therapy, hypoxia and UV-irradiation leads to an increase in histone deacetylase 8 (HDAC8) expression/activity, and in turn, the adoption of a drug-resistant, invasive phenotype. Systems level analyses using mass spectrometry-based phosphoproteomics implicated HDAC8 in the regulation of MAPK and AP-1 signaling pathways. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in in vivo xenograft models. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase (RTK) activation leading to Ras/CRAF/MEK/ERK signaling. Although HDACs primarily function at the histone level, they also regulate signaling through the modulation of non-histone substrates. In line with this, HDAC8 introduction decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine residue 273 reduced the transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition through increased RTK expression and enhanced MAPK pathway activity. In vivo xenograft studies confirmed the key role of HDAC8 in therapeutic adaptation, with both non-selective and HDAC8-specific inhibitors enhancing the durability of response to BRAF inhibitor therapy. Our studies demonstrate that HDAC8-specific inhibitors could represent an excellent strategy to limit the adaptation of melanoma cells to multiple stresses and therapeutic interventions, including BRAF-MEK inhibitor combinations.
Project description:Systems level analyses using mass spectrometry-based phosphoproteomics and RNA-Seq implicated HDAC8 in the regulation of MAPK and AP-1 signaling pathways. Introduction of HDAC8 into drug-naïve melanoma cells conveyed resistance both in vitro and in in vivo xenograft models. HDAC8-mediated BRAF inhibitor resistance was mediated via receptor tyrosine kinase (RTK) activation leading to Ras/CRAF/MEK/ERK signaling. Although HDACs primarily function at the histone level, they also regulate signaling through the modulation of non-histone substrates. In line with this, HDAC8 introduction decreased the acetylation of c-Jun, increasing its transcriptional activity and enriching for an AP-1 gene signature. Mutation of the putative c-Jun acetylation site at lysine residue 273 reduced the transcriptional activation of c-Jun in melanoma cells and conveyed resistance to BRAF inhibition through increased RTK expression and enhanced MAPK pathway activity.