Project description:While tissue and lineage-specific super-enhancers (SEs) regulate cell fate decision during development, the nature of Castration Resistant Prostate Cancer (CRPC)-specific SEs (CSEs) is unknown. Herein we report the lysine 13 (K13) acetylation of HOXB13 mediated by the histone acetyltransferase CBP/p300 regulates prostate tumor autonomy. The acK13-HOXB13 shadows H3K27ac at lineage specific SEs and surpasses it at CSEs. In contrast, mutation of HOXB13 at K13 sensitizes CRPCs to Enzalutamide, disables spheroid and xenograft tumor formation. Mechanistically, the acK13-HOXB13 interacts with chromatin remodeling bromodomain proteins to regulate tumor-specific CSE selection. These CSEs sprout at critical lineage genes NKX3-1, Androgen receptor (AR), AR regulator ACK1 tyrosine kinase and tyrosine kinase ligands regulating angiogenesis. Single-cell transcriptomic analysis of human prostate tumor organoids reveal ACK1 expression underlies sensitivity to the small molecule inhibitor (R)-9b over AR-targeted agents. Collectively, our studies reveal acK13-HOXB13 regulated epigenome as a key cog in prostate cancer cell autonomy.
Project description:While tissue and lineage-specific super-enhancers (SEs) regulate cell fate decision during development, the nature of Castration Resistant Prostate Cancer (CRPC)-specific SEs (CSEs) that drive resistance to AR-targeted therapies is unknown. Herein we report the lysine 13 (K13)-acetylation of Homeodomain transcription factor HOXB13 as a critical feature underlying CSE exclusivity. The histone acetyltransferase (HAT) CBP/p300 specifically acetylates HOXB13 (acK13-HOXB13) in prostate cancer cells. The acK13-HOXB13 enriched CSEs sprout at critical lineage genes such as the NKX3-1, Androgen receptor (AR), AR regulator ACK1/TNK2 a tyrosine-kinase and tyrosine kinase ligands associated with angiogenesis, including VEGFA and ANGPT2/ANGPTL3 to expedite prostate tumor autonomy.
Project description:Treatment induced-resistance of CRPC is an imminent undesirable outcome in patients. Tissue and lineage-specific super-enhancers (SEs) determine cell fate and plasticity during development and disease respectively. However, the identity and function of CRPC-specific SEs (CSEs) regulated genes is unknown. Herein we report the lysine 13 acetylation of the prostate-enriched transcription factor HOXB13 (acK13-HOXB13) mediated by the histone acetyl transferase (HAT) CBP/p300 as a critical mechanism of CSE establishment. Mechanistically, acK13-HOXB13 establishes the CRPC enhanceosome comprising chromatin remodeling bromo-domain proteins SMARCA2/BAZ2B and the HAT p300/CBP which enable histone and non-histone protein acetylation at CSEs. Such CSEs sprout at tyrosine kinase genes encoding ACK1/TNK2, VEGFA, and ANGPT2/ANGPTL3 to increase pathogenic output in primary human tumors. These tyrosine kinase mediated signaling cascades establish robust networks to conduce growth, survival and androgen-bypass. Consistently, the loss of function acK13-HOXB13 mutants show significant reduction of proliferation, spheroid formation, and xenograft tumor growth that correlates with the high sensitivity to the AR-antagonist Enzalutamide. Targeting HOXB13 acetylation mediated CRPC-SE establishment at critical tyrosine kinase genes could therefore have significant clinical implications in preventing PC recurrence.
Project description:To understand the mechanistic role of HOXB13 lysine acetylation in CRPC development andd progression, differential gene expression analysis was performed following RNA-sequencing of the HOXB13K13A mutant versus the isogenic parental C4-2B to identify bonafide transcriptional targets of acetylated HOXB13. Chromatin remodeling and self-renewal genes were significantly impacted as a result of HOXB13-K13 mutation. These results suggested that single-site acetylation in HOXB13 is critical and may even be sufficient to promote cellular reprogramming associated with PC pathogenesis.
Project description:Thyroid autonomy is a frequent cause of thyrotoxicosis in regions with iodine deficiency. Epidemiological data suggest that the prevalence of thyroid autonomy is not only inversely correlated with the ambient iodine supply, but that iodide may also influence the course of pre-existing thyroid autonomy with possibly different effects on thyroid growth and function. Iodine slows TSH effects on thyroid growth stimulation and this effect is more pronounced in thyrocytes with constitutive cAMP activation i.e. in thyroid autonomy. Iodine induced growth alteration in early stage thyroid autonomy is conferred by induction of apoptosis and G2/M arrest. Transcriptome analysis revealed significant modulation of gene networks relevant to cell adhesion, cadherin signalling and ion binding with more pronounced effects in constitutively active FRTL-5 cells compared to normal FRTL-5 cells. The aim was to study iodide-induced changes in global gene expression in an in vitro model of thyroid autonomy. This model makes use of FRTL-5 cells with stable expression of a constitutively activating TSH receptor mutation or wild type TSHR as a control.
Project description:To identify potential cofactors of HOXB13 in suppressing lipogenic programs in prostate cancer cells, we performed tandem affinity purification followed by mass spectrometry analysis of WT and G84E HOXB13 expressed in LNCaP cells. Out of the HOXB13-enriched proteins are previously reported interactors such as AR and its cofactors FOXA1, GATA2, and NKX3. However, these interactions were not disrupted by G84E as compared to WT HOXB13. Interestingly, we found strong interactions of HOXB13 with HDAC1/3 and their corepressors NCoR1/2 and TBL1X. Notably, these interactions were drastically reduced by G84E mutation.
Project description:Self-sufficiency (autonomy) in growth signaling, the earliest recognized hallmark of cancer, is fuelled by the tumor cell’s ability to ‘secrete-and-sense’ growth factors; this translates into cell survival and proliferation that is self-sustained by auto-/paracrine secretion. Using breast cancer cells that are either endowed or impaired in growth signaling autonomy, here we reveal how autonomy impacts cancer progression. Autonomy is associated with enhanced molecular programs for stemness, immune evasiveness, proliferation, and epithelial-mesenchymal plasticity (EMP). Autonomy is both necessary and sufficient for anchorage-independent growth factor-restricted proliferation and resistance to anti-cancer drugs and is required for metastatic progression. Transcriptomic and proteomic studies show that autonomy is associated with self-sustained EGFR/ErbB signaling. A gene expression signature is derived (a.k.a., autonomy signature) which revealed that autonomy is induced in circulating tumor cells (CTCs) and particularly CTC clusters, the latter of which carry higher metastatic potential. Autonomy in CTCs tracks therapeutic response and prognosticates outcome. Autonomy is preserved during reversible (but not stable) EMT. These data support a role for growth signaling autonomy in multiple processes essential for the blood-borne dissemination of human breast cancer.