Exploring synthetic lethality between the PP6 phosphatase and SETDB1
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE216199 | GEO | 2025/10/20
REPOSITORIES: GEO
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Project description:Exploring synthetic lethality between the PP6 phosphatase and SETDB1
| PRJNA892551 | ENA
Project description:To assess the potential of PP6 as a therapeutic target in liver disorders, we attenuated expression of the PP6 catalytic subunit in HepG2 cells using lentiviral-transduced shRNA. Two PP6 knock-down (PP6KD) cell lines 18.5 and 19.5, (90% reduction of PP6-C protein content) were studied in depth. Both proliferated at a rate similar to control cells. However, flow cytometry indicated G2/M cell cycle arrest that was accounted for by a shift of the cells from a diploid to tetraploid state. PP6KD cells did not show an increase in apoptosis, nor did they exhibit reduced viability in the presence of bleomycin. Gene expression analysis by microarray showed attenuated anti-inflammatory signaling. Genes associated with DNA replication were downregulated. Mass spectrometry-based phosphoproteomic analysis yielded 80 phosphopeptides representing 56 proteins that were significantly affected by a stable reduction in PP6-C. Proteins involved in DNA replication, DNA damage repair and pre-mRNA splicing were overrepresented among these. PP6KD cells showed intact mTOR signaling.
2015-06-01 | GSE67891 | GEO
Project description:Light-induced phosphorylation is necessary and essential for the degradation of phytochrome-interacting factors (PIFs), the central repressors of photomorphogenesis. Although the kinases responsible for PIF phosphorylation have been extensively studied, the phosphatases underlying PIF dephosphorylation are largely unknown. Here, we real that mutation of FyPP1 and FyPP3, two catalytic subunits of PP6 phosphatases, promoted photomorphogenesis of seedlings in the dark. PP6 and PIFs functioned synergistically to repress photomorphogenesis. FyPP1 and FyPP3 directly interacted with and dephosphorylated PIF3 and PIF4. The light-induced degradation of PIF4 and the PIF transcriptional activities were dependent on PP6 activity. These data demonstrate that PP6 phosphatases repress photomorphogenesis through regulation of PIF phosphorylation, protein stability and transcriptional activity.
2019-09-04 | GSE128498 | GEO
Project description:The establishment of latent herpes simplex virus 1 (HSV-1) infection is controlled by promyelocytic leukemia nuclear bodies (PML NBs). Viral genomes are recruited to PML NBs structures and chromatinized by repressive H3.3K9me3 modified H3.3 histone variant to form viral DNA-containing PML-NBs (vDCP NBs). Exactly how this occurs is unclear. Here we identify an essential role for the HUSH complex and its SETDB1 and MORC2 effectors in the establishment and maintenance of latent herpes simplex virus 1 (HSV-1) infection. ChIP-seq analyses conducted on latently/quiescently infected primary human fibroblasts highlight the association of the H3K9me3 mark with the entire viral genome. We demonstrate the necessity of HUSH, SETDB1, and MORC2 in the establishment of repressive heterochromatin in vDCP NBs. Depletion of these components prior to viral infection results in reduced H3K9me3 levels across the entirety of latent/quiescent HSV-1 genomes, with minimal impact on the cellular genome as a whole. Once latency is established, depletion of HUSH, SETDB1, or MORC2 by shRNAs or the HIV-2ROD Vpx protein, induces the reactivation of HSV-1 in infected primary human fibroblasts as well as in human induced pluripotent stem cell-derived sensory neurons (hiPSDN). We discovered that the viral protein ICP0 induces MORC2 degradation via the proteasome machinery. This process is concurrent with ICP0 capability to initiate full HSV-1 reactivation, as well as the significant reactivation of HSV-1 upon MORC2 depletion in hiPSDN. Our data demonstrate the potent antiviral restriction activity of the HUSH/SETDB1/MORC2 complex to a non-integrated human herpesvirus, its close association with PML NBs, and introduces a new target for anti-herpesvirus therapy.
2024-09-24 | GSE263436 | GEO
Project description:Epigenetic dysregulation is a defining feature of tumorigenesis and has been implicated in immune escape. However, the epigenetic mechanisms that drive immune evasion in cancer are poorly understood. To systematically identify epigenetic factors that modulate the immune sensitivity of tumor cells, we performed in vivo loss of function screens targeting 936 chromatin regulators in mouse tumor models treated with immune checkpoint blockade. We identified the H3K9-methyltransferase SETDB1 and other members of the HUSH and KAP1 complexes as cell-intrinsic mediators of immune escape in tumor cells. We also found that amplification of SETDB1 (1q21) in human tumors is associated with reduced cytotoxic T-cell infiltration and resistance to immune checkpoint blockade. Mechanistically, we demonstrate that SETDB1 targets broad domains, hundreds of kilobases in size, many of which reside within the open genome compartment. These SETDB1 domains are enriched for transposable elements (TEs) and immune gene clusters associated with segmental duplication events, a central mechanism of mammalian genome evolution. SETDB1 loss derepresses latent TE-encoded regulatory elements and proximal immune genes within these repetitive regions, including canonical NKG2D ligands, and induces hundreds of putative TE-encoded viral antigens. Our study establishes SETDB1 as an epigenetic checkpoint that suppresses intrinsic immunogenicity in cancer cells, and thus represents a candidate target for immunotherapy.
2021-03-18 | GSE155972 | GEO
Project description:Griffin GK, Wu J, Iracheta-Vellve A, Patti JC, Hsu J, Davis T, Dele-Oni D, Du PP, Halawi A, Ishizuka JJ, Kim S, Klaeger S, Knudsen NH, Miller BC, Nguyen T, Olander K, Papanastasiou M, Rachimi S, Robitschek EJ, Schneider EM, Yeary M, Zimmer M, Jaffe JD, Carr SA, Doench JG, Haining WN, Yates KB, Manguso RT, Bernstein BE. 2020. Epigenetic dysregulation is a defining feature of tumorigenesis and has been implicated in immune escape, yet mechanisms that drive immune evasion are poorly understood. To systematically identify epigenetic factors that modulate the immune sensitivity of tumor cells, we performed in vivo CRISPR-Cas9 screens targeting 936 chromatin regulators in mouse tumor models treated with immune checkpoint blockade. We identified the H3K9-methyltransferase SETDB1 and other members of the HUSH and KAP1 complexes as cell-intrinsic mediators of immune escape in tumor cells. We also found that amplification of SETDB1 (1q21) in human tumors is associated with reduced cytotoxic T-cell infiltration and resistance to immune checkpoint blockade. Mechanistically, we demonstrate that SETDB1 represses broad domains, hundreds of kilobases in size, many of which reside within the open genome compartment. These SETDB1 domains are enriched for transposable elements (TEs) and immune gene clusters associated with segmental duplication events, a central mechanism of mammalian genome evolution. SETDB1 loss derepresses latent TE-encoded regulatory elements and proximal immune genes within these repetitive regions, including canonical co-stimulatory ligands, and induces hundreds of putative TE-encoded viral antigens. Our study establishes SETDB1 as an epigenetic checkpoint that suppresses intrinsic immunogenicity in cancer cells, and thus represents a candidate target for immunotherapy.
2020-12-11 | MSV000086580 | MassIVE
Project description:Because HES1 maintained PP6 protein level without affecting its mRNA level, we asked if HES1 directly interacted with PP6 in keratinocytes.
2022-11-09 | PXD037336 | Pride
Project description:Despite recent advances in the treatment of melanoma, many patients with metastatic disease still succumb to their disease. To identify tumor-intrinsic modulators of immunity to melanoma, we performed a whole-genome CRISPR screen in melanoma and identified multiple components of the HUSH complex, including Setdb1, as hits. We found that loss of Setdb1 leads to increased immunogenicity and complete tumor clearance in a CD8+ T-cell dependent manner. Mechanistically, loss of Setdb1 causes de-repression of endogenous retroviruses (ERVs) in melanoma cells and triggers tumor-cell intrinsic type-I interferon signaling, upregulation of MHC-I expression, and increased CD8+ T-cell infiltration. Furthermore, spontaneous immune clearance observed in Setdb1-/- tumors results in subsequent protection from other ERV-expressing tumor lines, supporting the functional anti-tumor role of ERV-specific CD8+ T-cells found in the Setdb1-/- microenvironment. Blocking the type-I interferon receptor in mice grafted with Setdb1-/- tumors decreases immunogenicity by decreasing MHC-I expression, leading to decreased T-cell infiltration and increased melanoma growth comparable to Setdb1wt tumors. Together, these results indicate a critical role for Setdb1 and type-I interferons in generating an inflamed tumor microenvironment, and potentiating tumor-cell intrinsic immunogenicity in melanoma. This study further emphasizes regulators of ERV expression and type-I interferon expression as potential therapeutic targets for augmenting anti-cancer immune responses.
2023-12-31 | GSE232413 | GEO
Project description:Despite recent advances in the treatment of melanoma, many patients with metastatic disease still succumb to their disease. To identify tumor-intrinsic modulators of immunity to melanoma, we performed a whole-genome CRISPR screen in melanoma and identified multiple components of the HUSH complex, including Setdb1, as hits. We found that loss of Setdb1 leads to increased immunogenicity and complete tumor clearance in a CD8+ T-cell dependent manner. Mechanistically, loss of Setdb1 causes de-repression of endogenous retroviruses (ERVs) in melanoma cells and triggers tumor-cell intrinsic type-I interferon signaling, upregulation of MHC-I expression, and increased CD8+ T-cell infiltration. Furthermore, spontaneous immune clearance observed in Setdb1-/- tumors results in subsequent protection from other ERV-expressing tumor lines, supporting the functional anti-tumor role of ERV-specific CD8+ T-cells found in the Setdb1-/- microenvironment. Blocking the type-I interferon receptor in mice grafted with Setdb1-/- tumors decreases immunogenicity by decreasing MHC-I expression, leading to decreased T-cell infiltration and increased melanoma growth comparable to Setdb1wt tumors. Together, these results indicate a critical role for Setdb1 and type-I interferons in generating an inflamed tumor microenvironment, and potentiating tumor-cell intrinsic immunogenicity in melanoma. This study further emphasizes regulators of ERV expression and type-I interferon expression as potential therapeutic targets for augmenting anti-cancer immune responses.
2023-12-31 | GSE232411 | GEO
Project description:Von Hippel-Lindau (VHL) is a tumor suppressor that functions as the substrate recognition subunit of the CRL2VHL E3 complex. While substrates of VHL have been identified, its tumor suppressive role remains to be fully understood. For further determination of VHL substrates, we analyzed the physical interactome of VHL and identified the histone H3K9 methyltransferase SETBD1 as a novel target. SETDB1 undergoes oxygen-dependent hydroxylation by prolyl hydroxylase domain proteins (PHD) and the CRL2VHL complex recognizes hydroxylated SETDB1 for ubiquitin-mediated degradation. Under hypoxic conditions, SETDB1 accumulates by escaping CRL2VHL activity. Loss of SETDB1 in hypoxia compared with that in normoxia escalates the production of transposable element (TE)-derived double-stranded RNAs (dsRNAs), thereby hyperactivating the immune-inflammatory response. In addition, strong derepression of TEs in hypoxic cells lacking SETDB1 triggers DNA damage-induced death. Our collective results support a molecular mechanism of oxygen-dependent SETDB1 degradation by the CRL2VHL E3 complex and reveal a role of SETDB1 in genome stability under hypoxia.
2024-01-26 | PXD037104 | Pride