1
|
Fitzgerald TW, Gerety SS, Jones WD, van Kogelenberg M, King DA, McRae J, Morley KI, Parthiban V, Al-Turki S, Ambridge K, Barrett DM, Bayzetinova T, Clayton S, Coomber EL, Gribble S, Jones P, Krishnappa N, Mason LE, Middleton A, Miller R, Prigmore E, Rajan D, Sifrim A, Tivey AR, Ahmed M, Akawi N, Andrews R, Anjum U, Archer H, Armstrong R, Balasubramanian M, Banerjee R, Baralle D, Batstone P, Baty D, Bennett C, Berg J, Bernhard B, Bevan AP, Blair E, Blyth M, Bohanna D, Bourdon L, Bourn D, Brady A, Bragin E, Brewer C, Brueton L, Brunstrom K, Bumpstead SJ, Bunyan DJ, Burn J, Burton J, Canham N, Castle B, Chandler K, Clasper S, Clayton-Smith J, Cole T, Collins A, Collinson MN, Connell F, Cooper N, Cox H, Cresswell L, Cross G, Crow Y, D’Alessandro M, Dabir T, Davidson R, Davies S, Dean J, Deshpande C, Devlin G, Dixit A, Dominiczak A, Donnelly C, Donnelly D, Douglas A, Duncan A, Eason J, Edkins S, Ellard S, Ellis P, Elmslie F, Evans K, Everest S, Fendick T, Fisher R, Flinter F, Foulds N, Fryer A, Fu B, Gardiner C, Gaunt L, Ghali N, Gibbons R, Gomes Pereira SL, Goodship J, Goudie D, et alFitzgerald TW, Gerety SS, Jones WD, van Kogelenberg M, King DA, McRae J, Morley KI, Parthiban V, Al-Turki S, Ambridge K, Barrett DM, Bayzetinova T, Clayton S, Coomber EL, Gribble S, Jones P, Krishnappa N, Mason LE, Middleton A, Miller R, Prigmore E, Rajan D, Sifrim A, Tivey AR, Ahmed M, Akawi N, Andrews R, Anjum U, Archer H, Armstrong R, Balasubramanian M, Banerjee R, Baralle D, Batstone P, Baty D, Bennett C, Berg J, Bernhard B, Bevan AP, Blair E, Blyth M, Bohanna D, Bourdon L, Bourn D, Brady A, Bragin E, Brewer C, Brueton L, Brunstrom K, Bumpstead SJ, Bunyan DJ, Burn J, Burton J, Canham N, Castle B, Chandler K, Clasper S, Clayton-Smith J, Cole T, Collins A, Collinson MN, Connell F, Cooper N, Cox H, Cresswell L, Cross G, Crow Y, D’Alessandro M, Dabir T, Davidson R, Davies S, Dean J, Deshpande C, Devlin G, Dixit A, Dominiczak A, Donnelly C, Donnelly D, Douglas A, Duncan A, Eason J, Edkins S, Ellard S, Ellis P, Elmslie F, Evans K, Everest S, Fendick T, Fisher R, Flinter F, Foulds N, Fryer A, Fu B, Gardiner C, Gaunt L, Ghali N, Gibbons R, Gomes Pereira SL, Goodship J, Goudie D, Gray E, Greene P, Greenhalgh L, Harrison L, Hawkins R, Hellens S, Henderson A, Hobson E, Holden S, Holder S, Hollingsworth G, Homfray T, Humphreys M, Hurst J, Ingram S, Irving M, Jarvis J, Jenkins L, Johnson D, Jones D, Jones E, Josifova D, Joss S, Kaemba B, Kazembe S, Kerr B, Kini U, Kinning E, Kirby G, Kirk C, Kivuva E, Kraus A, Kumar D, Lachlan K, Lam W, Lampe A, Langman C, Lees M, Lim D, Lowther G, Lynch SA, Magee A, Maher E, Mansour S, Marks K, Martin K, Maye U, McCann E, McConnell V, McEntagart M, McGowan R, McKay K, McKee S, McMullan DJ, McNerlan S, Mehta S, Metcalfe K, Miles E, Mohammed S, Montgomery T, Moore D, Morgan S, Morris A, Morton J, Mugalaasi H, Murday V, Nevitt L, Newbury-Ecob R, Norman A, O'Shea R, Ogilvie C, Park S, Parker MJ, Patel C, Paterson J, Payne S, Phipps J, Pilz DT, Porteous D, Pratt N, Prescott K, Price S, Pridham A, Procter A, Purnell H, Ragge N, Rankin J, Raymond L, Rice D, Robert L, Roberts E, Roberts G, Roberts J, Roberts P, Ross A, Rosser E, Saggar A, Samant S, Sandford R, Sarkar A, Schweiger S, Scott C, Scott R, Selby A, Seller A, Sequeira C, Shannon N, Sharif S, Shaw-Smith C, Shearing E, Shears D, Simonic I, Simpkin D, Singzon R, Skitt Z, Smith A, Smith B, Smith K, Smithson S, Sneddon L, Splitt M, Squires M, Stewart F, Stewart H, Suri M, Sutton V, Swaminathan GJ, Sweeney E, Tatton-Brown K, Taylor C, Taylor R, Tein M, Temple IK, Thomson J, Tolmie J, Torokwa A, Treacy B, Turner C, Turnpenny P, Tysoe C, Vandersteen A, Vasudevan P, Vogt J, Wakeling E, Walker D, Waters J, Weber A, Wellesley D, Whiteford M, Widaa S, Wilcox S, Williams D, Williams N, Woods G, Wragg C, Wright M, Yang F, Yau M, Carter NP, Parker M, Firth HV, FitzPatrick DR, Wright CF, Barrett JC, Hurles ME. Large-scale discovery of novel genetic causes of developmental disorders. Nature 2015; 519:223-8. [PMID: 25533962 PMCID: PMC5955210 DOI: 10.1038/nature14135] [Show More Authors] [Citation(s) in RCA: 834] [Impact Index Per Article: 83.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 12/04/2014] [Indexed: 12/23/2022]
Abstract
Despite three decades of successful, predominantly phenotype-driven discovery of the genetic causes of monogenic disorders, up to half of children with severe developmental disorders of probable genetic origin remain without a genetic diagnosis. Particularly challenging are those disorders rare enough to have eluded recognition as a discrete clinical entity, those with highly variable clinical manifestations, and those that are difficult to distinguish from other, very similar, disorders. Here we demonstrate the power of using an unbiased genotype-driven approach to identify subsets of patients with similar disorders. By studying 1,133 children with severe, undiagnosed developmental disorders, and their parents, using a combination of exome sequencing and array-based detection of chromosomal rearrangements, we discovered 12 novel genes associated with developmental disorders. These newly implicated genes increase by 10% (from 28% to 31%) the proportion of children that could be diagnosed. Clustering of missense mutations in six of these newly implicated genes suggests that normal development is being perturbed by an activating or dominant-negative mechanism. Our findings demonstrate the value of adopting a comprehensive strategy, both genome-wide and nationwide, to elucidate the underlying causes of rare genetic disorders.
Collapse
|
research-article |
10 |
834 |
2
|
Ma MZ, Chu BF, Zhang Y, Weng MZ, Qin YY, Gong W, Quan ZW. Long non-coding RNA CCAT1 promotes gallbladder cancer development via negative modulation of miRNA-218-5p. Cell Death Dis 2015; 6:e1583. [PMID: 25569100 PMCID: PMC4669740 DOI: 10.1038/cddis.2014.541] [Citation(s) in RCA: 297] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 09/12/2014] [Accepted: 11/13/2014] [Indexed: 02/05/2023]
Abstract
Protein-coding genes account for only ~2% of the human genome, whereas the vast majority of transcripts are non-coding RNAs (ncRNAs) including long ncRNAs (lncRNAs). A growing volume of literature has proposed that lncRNAs are important factors in cancer. Colon cancer-associated transcript-1 (CCAT1), an lncRNA, which was first identified in colon cancer, was previously shown to promote tumor development and be a negative prognostic factor in gastric cancer. However, the mechanism through which CCAT1 exerts its oncogenic activity remains largely unknown. Recently, a novel regulatory mechanism has been proposed in which RNAs can cross-talk with each other via competing shared for microRNAs (miRNAs). The proposed competitive endogenous RNAs could mediate the bioavailability of miRNAs on their targets, thus imposing another level of posttranscriptional regulation. In this study, we demonstrated that CCAT1 was upregulated in gallbladder cancer (GBC) tissues. CCAT1 silencing downregulated, whereas CCAT1 overexpression enhanced the expression of miRNA-218-5p target gene Bmi1 through competitively 'spongeing' miRNA-218-5p. Our data revealed that CCAT1 knockdown impaired the proliferation and invasiveness of GBC cells, at least in part through affecting miRNA-218-5p-mediated regulation of Bmi1. Moreover, CCAT1 transcript level was correlated with Bmi1 mRNA level in GBC tissues. Together, these results suggest that CCAT1 is a driver of malignancy, which acts in part through 'spongeing' miRNA-218-5p.
Collapse
|
research-article |
10 |
297 |
3
|
Zhang L, Zhou Y, Cheng C, Cui H, Cheng L, Kong P, Wang J, Li Y, Chen W, Song B, Wang F, Jia Z, Li L, Li Y, Yang B, Liu J, Shi R, Bi Y, Zhang Y, Wang J, Zhao Z, Hu X, Yang J, Li H, Gao Z, Chen G, Huang X, Yang X, Wan S, Chen C, Li B, Tan Y, Chen L, He M, Xie S, Li X, Zhuang X, Wang M, Xia Z, Luo L, Ma J, Dong B, Zhao J, Song Y, Ou Y, Li E, Xu L, Wang J, Xi Y, Li G, Xu E, Liang J, Yang X, Guo J, Chen X, Zhang Y, Li Q, Liu L, Li Y, Zhang X, Yang H, Lin D, Cheng X, Guo Y, Wang J, Zhan Q, Cui Y. Genomic analyses reveal mutational signatures and frequently altered genes in esophageal squamous cell carcinoma. Am J Hum Genet 2015; 96:597-611. [PMID: 25839328 PMCID: PMC4385186 DOI: 10.1016/j.ajhg.2015.02.017] [Citation(s) in RCA: 274] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 02/26/2015] [Indexed: 02/07/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide and the fourth most lethal cancer in China. However, although genomic studies have identified some mutations associated with ESCC, we know little of the mutational processes responsible. To identify genome-wide mutational signatures, we performed either whole-genome sequencing (WGS) or whole-exome sequencing (WES) on 104 ESCC individuals and combined our data with those of 88 previously reported samples. An APOBEC-mediated mutational signature in 47% of 192 tumors suggests that APOBEC-catalyzed deamination provides a source of DNA damage in ESCC. Moreover, PIK3CA hotspot mutations (c.1624G>A [p.Glu542Lys] and c.1633G>A [p.Glu545Lys]) were enriched in APOBEC-signature tumors, and no smoking-associated signature was observed in ESCC. In the samples analyzed by WGS, we identified focal (<100 kb) amplifications of CBX4 and CBX8. In our combined cohort, we identified frequent inactivating mutations in AJUBA, ZNF750, and PTCH1 and the chromatin-remodeling genes CREBBP and BAP1, in addition to known mutations. Functional analyses suggest roles for several genes (CBX4, CBX8, AJUBA, and ZNF750) in ESCC. Notably, high activity of hedgehog signaling and the PI3K pathway in approximately 60% of 104 ESCC tumors indicates that therapies targeting these pathways might be particularly promising strategies for ESCC. Collectively, our data provide comprehensive insights into the mutational signatures of ESCC and identify markers for early diagnosis and potential therapeutic targets.
Collapse
|
research-article |
10 |
274 |
4
|
Plys AJ, Davis CP, Kim J, Rizki G, Keenen MM, Marr SK, Kingston RE. Phase separation of Polycomb-repressive complex 1 is governed by a charged disordered region of CBX2. Genes Dev 2019; 33:799-813. [PMID: 31171700 PMCID: PMC6601514 DOI: 10.1101/gad.326488.119] [Citation(s) in RCA: 253] [Impact Index Per Article: 42.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 05/08/2019] [Indexed: 12/15/2022]
Abstract
Mammalian development requires effective mechanisms to repress genes whose expression would generate inappropriately specified cells. The Polycomb-repressive complex 1 (PRC1) family complexes are central to maintaining this repression. These include a set of canonical PRC1 complexes, each of which contains four core proteins, including one from the CBX family. These complexes have been shown previously to reside in membraneless organelles called Polycomb bodies, leading to speculation that canonical PRC1 might be found in a separate phase from the rest of the nucleus. We show here that reconstituted PRC1 readily phase-separates into droplets in vitro at low concentrations and physiological salt conditions. This behavior is driven by the CBX2 subunit. Point mutations in an internal domain of Cbx2 eliminate phase separation. These same point mutations eliminate the formation of puncta in cells and have been shown previously to eliminate nucleosome compaction in vitro and generate axial patterning defects in mice. Thus, the domain of CBX2 that is important for phase separation is the same domain shown previously to be important for chromatin compaction and proper development, raising the possibility of a mechanistic or evolutionary link between these activities.
Collapse
|
Research Support, N.I.H., Extramural |
6 |
253 |
5
|
Fan P, Liu P, Song P, Chen X, Ma X. Moderate dietary protein restriction alters the composition of gut microbiota and improves ileal barrier function in adult pig model. Sci Rep 2017; 7:43412. [PMID: 28252026 PMCID: PMC5333114 DOI: 10.1038/srep43412] [Citation(s) in RCA: 234] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/23/2017] [Indexed: 12/22/2022] Open
Abstract
This study was conducted to investigate impacts of dietary protein levels on gut bacterial community and gut barrier. The intestinal microbiota of finishing pigs, fed with 16%, 13% and 10% crude protein (CP) in diets, respectively, were investigated using Illumina MiSeq sequencing. The ileal bacterial richness tended to decrease when the dietary protein concentration reduced from 16% to 10%. The proportion of Clostridium_sensu_stricto_1 in ileum significantly decreased, whereas Escherichia-Shigella increased with reduction of protein concentration. In colon, the proportion of Clostridium_sensu_stricto_1 and Turicibacter increased, while the proportion of RC9_gut_group significantly decreased with the dietary protein reduction. Notably, the proportion of Peptostreptococcaceae was higher in both ileum and colon of 13% CP group. As for metabolites, the intestinal concentrations of SCFAs and biogenic amines decreased with the dietary protein reduction. The 10% CP dietary treatment damaged ileal mucosal morphology, and decreased the expression of biomarks of intestinal cells (Lgr5 and Bmi1), whereas the expression of tight junction proteins (occludin and claudin) in 13% CP group were higher than the other two groups. In conclusion, moderate dietary protein restriction (13% CP) could alter the bacterial community and metabolites, promote colonization of beneficial bacteria in both ileum and colon, and improve gut barrier function.
Collapse
|
research-article |
8 |
234 |
6
|
Chen D, Wu M, Li Y, Chang I, Yuan Q, Ekimyan-Salvo M, Deng P, Yu B, Yu Y, Dong J, Szymanski JM, Ramadoss S, Li J, Wang CY. Targeting BMI1 + Cancer Stem Cells Overcomes Chemoresistance and Inhibits Metastases in Squamous Cell Carcinoma. Cell Stem Cell 2017; 20:621-634.e6. [PMID: 28285905 PMCID: PMC5419860 DOI: 10.1016/j.stem.2017.02.003] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 08/08/2016] [Accepted: 02/06/2017] [Indexed: 02/07/2023]
Abstract
Squamous cell carcinoma in the head and neck (HNSCC) is a common yet poorly understood cancer, with adverse clinical outcomes due to treatment resistance, recurrence, and metastasis. Putative cancer stem cells (CSCs) have been identified in HNSCC, and BMI1 expression has been linked to these phenotypes, but optimal treatment strategies to overcome chemotherapeutic resistance and eliminate metastases have not yet been identified. Here we show through lineage tracing and genetic ablation that BMI1+ CSCs mediate invasive growth and cervical lymph node metastasis in a mouse model of HNSCC. This model and primary human HNSCC samples contain highly tumorigenic, invasive, and cisplatin-resistant BMI1+ CSCs, which exhibit increased AP-1 activity that drives invasive growth and metastasis of HNSCC. Inhibiting AP-1 or BMI1 sensitized tumors to cisplatin-based chemotherapy, and it eliminated lymph node metastases by targeting CSCs and the tumor bulk, suggesting potential regimens to overcome resistance to treatments and eradicate HNSCC metastasis.
Collapse
|
Research Support, N.I.H., Extramural |
8 |
215 |
7
|
Endoh M, Endo TA, Endoh T, Isono KI, Sharif J, Ohara O, Toyoda T, Ito T, Eskeland R, Bickmore WA, Vidal M, Bernstein BE, Koseki H. Histone H2A mono-ubiquitination is a crucial step to mediate PRC1-dependent repression of developmental genes to maintain ES cell identity. PLoS Genet 2012; 8:e1002774. [PMID: 22844243 PMCID: PMC3405999 DOI: 10.1371/journal.pgen.1002774] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Accepted: 05/04/2012] [Indexed: 01/08/2023] Open
Abstract
Two distinct Polycomb complexes, PRC1 and PRC2, collaborate to maintain epigenetic repression of key developmental loci in embryonic stem cells (ESCs). PRC1 and PRC2 have histone modifying activities, catalyzing mono-ubiquitination of histone H2A (H2AK119u1) and trimethylation of H3 lysine 27 (H3K27me3), respectively. Compared to H3K27me3, localization and the role of H2AK119u1 are not fully understood in ESCs. Here we present genome-wide H2AK119u1 maps in ESCs and identify a group of genes at which H2AK119u1 is deposited in a Ring1-dependent manner. These genes are a distinctive subset of genes with H3K27me3 enrichment and are the central targets of Polycomb silencing that are required to maintain ESC identity. We further show that the H2A ubiquitination activity of PRC1 is dispensable for its target binding and its activity to compact chromatin at Hox loci, but is indispensable for efficient repression of target genes and thereby ESC maintenance. These data demonstrate that multiple effector mechanisms including H2A ubiquitination and chromatin compaction combine to mediate PRC1-dependent repression of genes that are crucial for the maintenance of ESC identity. Utilization of these diverse effector mechanisms might provide a means to maintain a repressive state that is robust yet highly responsive to developmental cues during ES cell self-renewal and differentiation. Polycomb-group (PcG) proteins play essential roles in the epigenetic regulation of gene expression during development. PcG proteins form two distinct multimeric complexes, PRC1 and PRC2. In the widely accepted hierarchical model, PRC2 is recruited to specific genomic locations and catalyzes trimethylation of H3 lysine 27 (H3K27me3), thereby creating binding sites for PRC1, which then catalyzes mono-ubiquitination of histone H2A (H2AK119u1). Recently, PRC1 has been shown to be able to compact chromatin structure at target loci independently of its histone ubiquitination activity. Therefore, the role of H2AK119u1 still remains unclear. To gain insight into this issue, we used ChIP-on-chip analysis to map H2AK119u1 genome-wide in mouse ES cells (ESCs). The data demonstrate that H2AK119u1 occupies a distinctive subset of genes with H3K27me3 enrichment. These genes are the central targets of Polycomb silencing to maintain ESC identity. We further show that the H2A ubiquitination activity of PRC1 is dispensable for its target binding and its activity to compact chromatin at Hox loci, but is indispensable for efficient repression of target genes and therefore ESC maintenance. We propose that multiple effector mechanisms including H2A ubiquitination and chromatin compaction combine to mediate PRC1-dependent repression of developmental genes to maintain the identity of ESCs.
Collapse
|
Research Support, Non-U.S. Gov't |
13 |
207 |
8
|
Hauri S, Comoglio F, Seimiya M, Gerstung M, Glatter T, Hansen K, Aebersold R, Paro R, Gstaiger M, Beisel C. A High-Density Map for Navigating the Human Polycomb Complexome. Cell Rep 2016; 17:583-595. [PMID: 27705803 DOI: 10.1016/j.celrep.2016.08.096] [Citation(s) in RCA: 202] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/23/2016] [Accepted: 08/30/2016] [Indexed: 12/20/2022] Open
Abstract
Polycomb group (PcG) proteins are major determinants of gene silencing and epigenetic memory in higher eukaryotes. Here, we systematically mapped the human PcG complexome using a robust affinity purification mass spectrometry approach. Our high-density protein interaction network uncovered a diverse range of PcG complexes. Moreover, our analysis identified PcG interactors linking them to the PcG system, thus providing insight into the molecular function of PcG complexes and mechanisms of recruitment to target genes. We identified two human PRC2 complexes and two PR-DUB deubiquitination complexes, which contain the O-linked N-acetylglucosamine transferase OGT1 and several transcription factors. Finally, genome-wide profiling of PR-DUB components indicated that the human PR-DUB and PRC1 complexes bind distinct sets of target genes, suggesting differential impact on cellular processes in mammals.
Collapse
|
|
9 |
202 |
9
|
Fursova NA, Blackledge NP, Nakayama M, Ito S, Koseki Y, Farcas AM, King HW, Koseki H, Klose RJ. Synergy between Variant PRC1 Complexes Defines Polycomb-Mediated Gene Repression. Mol Cell 2019; 74:1020-1036.e8. [PMID: 31029541 PMCID: PMC6561741 DOI: 10.1016/j.molcel.2019.03.024] [Citation(s) in RCA: 186] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/04/2019] [Accepted: 03/21/2019] [Indexed: 01/30/2023]
Abstract
The Polycomb system modifies chromatin and plays an essential role in repressing gene expression to control normal mammalian development. However, the components and mechanisms that define how Polycomb protein complexes achieve this remain enigmatic. Here, we use combinatorial genetic perturbation coupled with quantitative genomics to discover the central determinants of Polycomb-mediated gene repression in mouse embryonic stem cells. We demonstrate that canonical Polycomb repressive complex 1 (PRC1), which mediates higher-order chromatin structures, contributes little to gene repression. Instead, we uncover an unexpectedly high degree of synergy between variant PRC1 complexes, which is fundamental to gene repression. We further demonstrate that variant PRC1 complexes are responsible for distinct pools of H2A monoubiquitylation that are associated with repression of Polycomb target genes and silencing during X chromosome inactivation. Together, these discoveries reveal a new variant PRC1-dependent logic for Polycomb-mediated gene repression.
Collapse
|
research-article |
6 |
186 |
10
|
Blackledge NP, Fursova NA, Kelley JR, Huseyin MK, Feldmann A, Klose RJ. PRC1 Catalytic Activity Is Central to Polycomb System Function. Mol Cell 2020; 77:857-874.e9. [PMID: 31883950 PMCID: PMC7033600 DOI: 10.1016/j.molcel.2019.12.001] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 10/21/2019] [Accepted: 12/02/2019] [Indexed: 01/01/2023]
Abstract
The Polycomb repressive system is an essential chromatin-based regulator of gene expression. Despite being extensively studied, how the Polycomb system selects its target genes is poorly understood, and whether its histone-modifying activities are required for transcriptional repression remains controversial. Here, we directly test the requirement for PRC1 catalytic activity in Polycomb system function. To achieve this, we develop a conditional mutation system in embryonic stem cells that completely removes PRC1 catalytic activity. Using this system, we demonstrate that catalysis by PRC1 drives Polycomb chromatin domain formation and long-range chromatin interactions. Furthermore, we show that variant PRC1 complexes with DNA-binding activities occupy target sites independently of PRC1 catalytic activity, providing a putative mechanism for Polycomb target site selection. Finally, we discover that Polycomb-mediated gene repression requires PRC1 catalytic activity. Together these discoveries provide compelling evidence that PRC1 catalysis is central to Polycomb system function and gene regulation.
Collapse
|
research-article |
5 |
174 |
11
|
Zhou Y, Wang L, Vaseghi HR, Liu Z, Lu R, Alimohamadi S, Yin C, Fu JD, Wang GG, Liu J, Qian L. Bmi1 Is a Key Epigenetic Barrier to Direct Cardiac Reprogramming. Cell Stem Cell 2016; 18:382-95. [PMID: 26942853 PMCID: PMC4779178 DOI: 10.1016/j.stem.2016.02.003] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 11/01/2015] [Accepted: 02/12/2016] [Indexed: 02/08/2023]
Abstract
Direct reprogramming of induced cardiomyocytes (iCMs) suffers from low efficiency and requires extensive epigenetic repatterning, although the underlying mechanisms are largely unknown. To address these issues, we screened for epigenetic regulators of iCM reprogramming and found that reducing levels of the polycomb complex gene Bmi1 significantly enhanced induction of beating iCMs from neonatal and adult mouse fibroblasts. The inhibitory role of Bmi1 in iCM reprogramming is mediated through direct interactions with regulatory regions of cardiogenic genes, rather than regulation of cell proliferation. Reduced Bmi1 expression corresponded with increased levels of the active histone mark H3K4me3 and reduced levels of repressive H2AK119ub at cardiogenic loci, and de-repression of cardiogenic gene expression during iCM conversion. Furthermore, Bmi1 deletion could substitute for Gata4 during iCM reprogramming. Thus, Bmi1 acts as a critical epigenetic barrier to iCM production. Bypassing this barrier simplifies iCM generation and increases yield, potentially streamlining iCM production for therapeutic purposes.
Collapse
|
Research Support, N.I.H., Extramural |
9 |
173 |
12
|
Molitor AM, Bu Z, Yu Y, Shen WH. Arabidopsis AL PHD-PRC1 complexes promote seed germination through H3K4me3-to-H3K27me3 chromatin state switch in repression of seed developmental genes. PLoS Genet 2014; 10:e1004091. [PMID: 24465219 PMCID: PMC3900384 DOI: 10.1371/journal.pgen.1004091] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 11/22/2013] [Indexed: 11/18/2022] Open
Abstract
Seed germination and subsequent seedling growth define crucial steps for entry into the plant life cycle. For those events to take place properly, seed developmental genes need to be silenced whereas vegetative growth genes are activated. Chromatin structure is generally known to play crucial roles in gene transcription control. However, the transition between active and repressive chromatin states during seed germination is still poorly characterized and the underlying molecular mechanisms remain largely unknown. Here we identified the Arabidopsis PHD-domain H3K4me3-binding ALFIN1-like proteins (ALs) as novel interactors of the Polycomb Repressive Complex 1 (PRC1) core components AtBMI1b and AtRING1a. The interactions were confirmed by diverse in vitro and in vivo assays and were shown to require the AL6 N-terminus containing PAL domain conserved in the AL family proteins and the AtRING1a C-terminus containing RAWUL domain conserved in animal and plant PRC1 ring-finger proteins (including AtRNIG1a/b and AtBMI1a/b). By T-DNA insertion mutant analysis, we found that simultaneous loss of AL6 and AL7 as well as loss of AtBMI1a and AtBMI1b retards seed germination and causes transcriptional derepression and a delayed chromatin state switch from H3K4me3 to H3K27me3 enrichment of several seed developmental genes (e.g. ABI3, DOG1, CRU3, CHO1). We found that AL6 and the PRC1 H3K27me3-reader component LHP1 directly bind at ABI3 and DOG1 loci. In light of these data, we propose that AL PHD-PRC1 complexes, built around H3K4me3, lead to a switch from the H3K4me3-associated active to the H3K27me3-associated repressive transcription state of seed developmental genes during seed germination. Our finding of physical interactions between PHD-domain proteins and PRC1 is striking and has important implications for understanding the connection between the two functionally opposite chromatin marks: H3K4me3 in activation and H3K27me3 in repression of gene transcription.
Collapse
|
Research Support, Non-U.S. Gov't |
11 |
159 |
13
|
Su W, Han HH, Wang Y, Zhang B, Zhou B, Cheng Y, Rumandla A, Gurrapu S, Chakraborty G, Su J, Yang G, Liang X, Wang G, Rosen N, Scher HI, Ouerfelli O, Giancotti FG. The Polycomb Repressor Complex 1 Drives Double-Negative Prostate Cancer Metastasis by Coordinating Stemness and Immune Suppression. Cancer Cell 2019; 36:139-155.e10. [PMID: 31327655 PMCID: PMC7210785 DOI: 10.1016/j.ccell.2019.06.009] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 04/28/2019] [Accepted: 06/17/2019] [Indexed: 12/14/2022]
Abstract
The mechanisms that enable immune evasion at metastatic sites are poorly understood. We show that the Polycomb Repressor Complex 1 (PRC1) drives colonization of the bones and visceral organs in double-negative prostate cancer (DNPC). In vivo genetic screening identifies CCL2 as the top prometastatic gene induced by PRC1. CCL2 governs self-renewal and induces the recruitment of M2-like tumor-associated macrophages and regulatory T cells, thus coordinating metastasis initiation with immune suppression and neoangiogenesis. A catalytic inhibitor of PRC1 cooperates with immune checkpoint therapy to reverse these processes and suppress metastasis in genetically engineered mouse transplantation models of DNPC. These results reveal that PRC1 coordinates stemness with immune evasion and neoangiogenesis and point to the potential clinical utility of targeting PRC1 in DNPC.
Collapse
MESH Headings
- Adenocarcinoma/drug therapy
- Adenocarcinoma/immunology
- Adenocarcinoma/metabolism
- Adenocarcinoma/secondary
- Animals
- Antineoplastic Agents, Immunological/pharmacology
- Antineoplastic Combined Chemotherapy Protocols/pharmacology
- Cell Movement/drug effects
- Cell Self Renewal/drug effects
- Chemokine CCL2/genetics
- Chemokine CCL2/metabolism
- Enzyme Inhibitors/pharmacology
- Gene Expression Regulation, Neoplastic
- Humans
- Lymphocytes, Tumor-Infiltrating/immunology
- Lymphocytes, Tumor-Infiltrating/metabolism
- Macrophages/immunology
- Macrophages/metabolism
- Male
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Mice, Knockout
- Mice, Nude
- Mice, SCID
- Neoplasm Metastasis
- Neoplastic Stem Cells/immunology
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- PC-3 Cells
- Polycomb Repressive Complex 1/antagonists & inhibitors
- Polycomb Repressive Complex 1/genetics
- Polycomb Repressive Complex 1/metabolism
- Prostatic Neoplasms/drug therapy
- Prostatic Neoplasms/immunology
- Prostatic Neoplasms/metabolism
- Prostatic Neoplasms/pathology
- Receptors, Androgen/deficiency
- Receptors, Androgen/genetics
- Receptors, CCR4/genetics
- Receptors, CCR4/metabolism
- Signal Transduction
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Tumor Escape/drug effects
- Xenograft Model Antitumor Assays
Collapse
|
Research Support, N.I.H., Extramural |
6 |
154 |
14
|
Gargiulo G, Cesaroni M, Serresi M, de Vries N, Hulsman D, Bruggeman SW, Lancini C, van Lohuizen M. In vivo RNAi screen for BMI1 targets identifies TGF-β/BMP-ER stress pathways as key regulators of neural- and malignant glioma-stem cell homeostasis. Cancer Cell 2013; 23:660-76. [PMID: 23680149 DOI: 10.1016/j.ccr.2013.03.030] [Citation(s) in RCA: 154] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 01/10/2013] [Accepted: 03/29/2013] [Indexed: 01/26/2023]
Abstract
In mouse and human neural progenitor and glioblastoma "stem-like" cells, we identified key targets of the Polycomb-group protein BMI1 by combining ChIP-seq with in vivo RNAi screening. We discovered that Bmi1 is important in the cellular response to the transforming growth factor-β/bone morphogenetic protein (TGF-β/BMP) and endoplasmic reticulum (ER) stress pathways, in part converging on the Atf3 transcriptional repressor. We show that Atf3 is a tumor-suppressor gene inactivated in human glioblastoma multiforme together with Cbx7 and a few other candidates. Acting downstream of the ER stress and BMP pathways, ATF3 binds to cell-type-specific accessible chromatin preloaded with AP1 and participates in the inhibition of critical oncogenic networks. Our data support the feasibility of combining ChIP-seq and RNAi screens in solid tumors and highlight multiple p16(INK4a)/p19(ARF)-independent functions for Bmi1 in development and cancer.
Collapse
|
|
12 |
154 |
15
|
Jian X, He H, Zhu J, Zhang Q, Zheng Z, Liang X, Chen L, Yang M, Peng K, Zhang Z, Liu T, Ye Y, Jiao H, Wang S, Zhou W, Ding Y, Li T. Hsa_circ_001680 affects the proliferation and migration of CRC and mediates its chemoresistance by regulating BMI1 through miR-340. Mol Cancer 2020; 19:20. [PMID: 32005118 PMCID: PMC6993513 DOI: 10.1186/s12943-020-1134-8] [Citation(s) in RCA: 148] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 01/09/2020] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Accumulating evidence indicates that circular RNAs (circRNAs) act as microRNA (miRNA) sponges to directly inhibit specific miRNAs and alter their ability to regulate gene expression at the post-transcriptional level; this mechanism is believed to occur in various cancers. However, the expression level, precise function and mechanism of circ_001680 in colorectal carcinoma (CRC) are largely unknown. METHODS qRT-PCR was used to detect the expression of circ_001680 and miR-340 in human CRC tissues and their matched normal tissues. Bioinformatics analyses and dual-fluorescence reporter assays were used to evaluate whether circ_001680 could bind to miR-340. Circ_001680 overexpression and knockdown cell lines were constructed to investigate the proliferation and migration abilities in vivo and in vitro through function-based experiments, including CCK8, plate clone formation, transwell, and wounding healing assays. The relationships among circ_001680, miR-340 and BMI1 were investigated by bioinformatics analyses, dual-fluorescence reporter system, FISH, RIP and RNA pull down assays. Sphere forming assays and flow cytometry analyses were used to assess the effect of circ_001680 on the stemness characteristics of CRC cells. RESULTS Circ_001680 was more highly expressed in of CRC tissue than in matched adjacent normal tissues from the same patients. Circ_001680 was observed to enhance the proliferation and migration capacity of CRC cells. Furthermore, dual-fluorescence reporter assays confirmed that circ_001680 affects the expression of BMI1 by targeting miR-340. More importantly, we also found that circ_001680 could promote the cancer stem cell (CSC) population in CRC and induce irinotecan therapeutic resistance by regulating the miR-340 target gene BMI1. CONCLUSIONS Our results demonstrated that circ_001680 is a part of a novel strategy to induce chemotherapy resistance in CRC through BMI1 upregulation. Moreover, circ_001680 may be a promising diagnostic and prognostic marker to determine the success of irinotecan-based chemotherapy.
Collapse
|
research-article |
5 |
148 |
16
|
Stuckey JI, Dickson BM, Cheng N, Liu Y, Norris JL, Cholensky SH, Tempel W, Qin S, Huber KG, Sagum C, Black K, Li F, Huang XP, Roth BL, Baughman BM, Senisterra G, Pattenden SG, Vedadi M, Brown PJ, Bedford MT, Min J, Arrowsmith CH, James LI, Frye SV. A cellular chemical probe targeting the chromodomains of Polycomb repressive complex 1. Nat Chem Biol 2016; 12:180-7. [PMID: 26807715 PMCID: PMC4755828 DOI: 10.1038/nchembio.2007] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 11/25/2015] [Indexed: 12/29/2022]
Abstract
We report the design and characterization of UNC3866, a potent antagonist of the methyllysine (Kme) reading function of the Polycomb CBX and CDY families of chromodomains. Polycomb CBX proteins regulate gene expression by targeting Polycomb repressive complex 1 (PRC1) to sites of H3K27me3 via their chromodomains. UNC3866 binds the chromodomains of CBX4 and CBX7 most potently, with a K(d) of ∼100 nM for each, and is 6- to 18-fold selective as compared to seven other CBX and CDY chromodomains while being highly selective over >250 other protein targets. X-ray crystallography revealed that UNC3866's interactions with the CBX chromodomains closely mimic those of the methylated H3 tail. UNC4195, a biotinylated derivative of UNC3866, was used to demonstrate that UNC3866 engages intact PRC1 and that EED incorporation into PRC1 is isoform dependent in PC3 prostate cancer cells. Finally, UNC3866 inhibits PC3 cell proliferation, consistent with the known ability of CBX7 overexpression to confer a growth advantage, whereas UNC4219, a methylated negative control compound, has negligible effects.
Collapse
|
Research Support, N.I.H., Extramural |
9 |
131 |
17
|
Lau MS, Schwartz MG, Kundu S, Savol AJ, Wang PI, Marr SK, Grau DJ, Schorderet P, Sadreyev RI, Tabin CJ, Kingston RE. Mutation of a nucleosome compaction region disrupts Polycomb-mediated axial patterning. Science 2017; 355:1081-1084. [PMID: 28280206 PMCID: PMC5503153 DOI: 10.1126/science.aah5403] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 01/26/2017] [Accepted: 02/10/2017] [Indexed: 12/26/2022]
Abstract
Nucleosomes play important structural and regulatory roles by tightly wrapping the DNA that constitutes the metazoan genome. The Polycomb group (PcG) proteins modulate nucleosomes to maintain repression of key developmental genes, including Hox genes whose temporal and spatial expression is tightly regulated to guide patterning of the anterior-posterior body axis. CBX2, a component of the mammalian Polycomb repressive complex 1 (PRC1), contains a compaction region that has the biochemically defined activity of bridging adjacent nucleosomes. Here, we demonstrate that a functional compaction region is necessary for proper body patterning, because mutating this region leads to homeotic transformations similar to those observed with PcG loss-of-function mutations. We propose that CBX2-driven nucleosome compaction is a key mechanism by which PcG proteins maintain gene silencing during mouse development.
Collapse
|
Research Support, N.I.H., Extramural |
8 |
122 |
18
|
Xi S, Xu H, Shan J, Tao Y, Hong JA, Inchauste S, Zhang M, Kunst TF, Mercedes L, Schrump DS. Cigarette smoke mediates epigenetic repression of miR-487b during pulmonary carcinogenesis. J Clin Invest 2013; 123:1241-61. [PMID: 23426183 PMCID: PMC3582115 DOI: 10.1172/jci61271] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 01/03/2013] [Indexed: 02/03/2023] Open
Abstract
MicroRNAs are critical mediators of stem cell pluripotency, differentiation, and malignancy. Limited information exists regarding microRNA alterations that facilitate initiation and progression of human lung cancers. In this study, array techniques were used to evaluate microRNA expression in normal human respiratory epithelia and lung cancer cells cultured in the presence or absence of cigarette smoke condensate (CSC). Under relevant exposure conditions, CSC significantly repressed miR-487b. Subsequent experiments demonstrated that miR-487b directly targeted SUZ12, BMI1, WNT5A, MYC, and KRAS. Repression of miR-487b correlated with overexpression of these targets in primary lung cancers and coincided with DNA methylation, de novo nucleosome occupancy, and decreased H2AZ and TCF1 levels within the miR-487b genomic locus. Deoxy-azacytidine derepressed miR-487b and attenuated CSC-mediated silencing of miR-487b. Constitutive expression of miR-487b abrogated Wnt signaling, inhibited in vitro proliferation and invasion of lung cancer cells mediated by CSC or overexpression of miR-487b targets, and decreased growth and metastatic potential of lung cancer cells in vivo. Collectively, these findings indicate that miR-487b is a tumor suppressor microRNA silenced by epigenetic mechanisms during tobacco-induced pulmonary carcinogenesis and suggest that DNA demethylating agents may be useful for activating miR-487b for lung cancer therapy.
Collapse
|
Research Support, N.I.H., Intramural |
12 |
110 |
19
|
Dong Q, Chen L, Lu Q, Sharma S, Li L, Morimoto S, Wang G. Quercetin attenuates doxorubicin cardiotoxicity by modulating Bmi-1 expression. Br J Pharmacol 2014; 171:4440-54. [PMID: 24902966 PMCID: PMC4209150 DOI: 10.1111/bph.12795] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/29/2014] [Accepted: 05/15/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Doxorubicin-based chemotherapy induces cardiotoxicity, which limits its clinical application. We previously reported the protective effects of quercetin against doxorubicin-induced hepatotoxicity. In this study, we tested the effects of quercetin on the expression of Bmi-1, a protein regulating mitochondrial function and ROS generation, as a mechanism underlying quercetin-mediated protection against doxorubicin-induced cardiotoxicity. EXPERIMENTAL APPROACH Effects of quercetin on doxorubicin-induced cardiotoxicity was evaluated using H9c2 cardiomyocytes and C57BL/6 mice. Changes in apoptosis, mitochondrial function, oxidative stress and related signalling were evaluated in H9c2 cells. Cardiac function, serum enzyme activity and reactive oxygen species (ROS) generation were measured in mice after a single injection of doxorubicin with or without quercetin pre-treatment. KEY RESULTS In H9c2 cells, quercetin reduced doxorubicin-induced apoptosis, mitochondrial dysfunction, ROS generation and DNA double-strand breaks. The quercetin-mediated protection against doxorubicin toxicity was characterized by decreased expression of Bid, p53 and oxidase (p47 and Nox1) and by increased expression of Bcl-2 and Bmi-1. Bmi-1 siRNA abolished the protective effect of quercetin against doxorubicin-induced toxicity in H9c2 cells. Furthermore, quercetin protected mice from doxorubicin-induced cardiac dysfunction that was accompanied by reduced ROS levels and lipid peroxidation, but enhanced the expression of Bmi-1 and anti-oxidative superoxide dismutase. CONCLUSIONS AND IMPLICATIONS Our results demonstrate that quercetin decreased doxorubicin-induced cardiotoxicity in vitro and in vivo by reducing oxidative stress by up-regulation of Bmi-1 expression. The findings presented in this study have potential applications in preventing doxorubicin-induced cardiomyopathy.
Collapse
|
research-article |
11 |
105 |
20
|
Hasegawa K, Sin HS, Maezawa S, Broering TJ, Kartashov AV, Alavattam KG, Ichijima Y, Zhang F, Bacon WC, Greis KD, Andreassen PR, Barski A, Namekawa SH. SCML2 establishes the male germline epigenome through regulation of histone H2A ubiquitination. Dev Cell 2015; 32:574-88. [PMID: 25703348 PMCID: PMC4391279 DOI: 10.1016/j.devcel.2015.01.014] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 12/23/2014] [Accepted: 01/16/2015] [Indexed: 01/03/2023]
Abstract
Gametogenesis is dependent on the expression of germline-specific genes. However, it remains unknown how the germline epigenome is distinctly established from that of somatic lineages. Here we show that genes commonly expressed in somatic lineages and spermatogenesis-progenitor cells undergo repression in a genome-wide manner in late stages of the male germline and identify underlying mechanisms. SCML2, a germline-specific subunit of a Polycomb repressive complex 1 (PRC1), establishes the unique epigenome of the male germline through two distinct antithetical mechanisms. SCML2 works with PRC1 and promotes RNF2-dependent ubiquitination of H2A, thereby marking somatic/progenitor genes on autosomes for repression. Paradoxically, SCML2 also prevents RNF2-dependent ubiquitination of H2A on sex chromosomes during meiosis, thereby enabling unique epigenetic programming of sex chromosomes for male reproduction. Our results reveal divergent mechanisms involving a shared regulator by which the male germline epigenome is distinguished from that of the soma and progenitor cells.
Collapse
|
Research Support, N.I.H., Extramural |
10 |
104 |
21
|
Zhang Y, Kang M, Zhang B, Meng F, Song J, Kaneko H, Shimamoto F, Tang B. m 6A modification-mediated CBX8 induction regulates stemness and chemosensitivity of colon cancer via upregulation of LGR5. Mol Cancer 2019; 18:185. [PMID: 31849331 PMCID: PMC6918584 DOI: 10.1186/s12943-019-1116-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/03/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Colon cancer (CC) cells can exhibit stemness and expansion capabilities, which contribute to resistance to conventional chemotherapies. Aberrant expression of CBX8 has been identified in many types of cancer, but the cause of this aberrant CBX8 expression and whether CBX8 is associated with stemness properties in CC remain unknown. METHODS qRT-PCR and IHC were applied to examine CBX8 levels in normal and chemoresistant CC tissues. Cancer cell stemness and chemosensitivity were evaluated by spheroid formation, colony formation, Western blot and flow cytometry assays. RNA-seq combined with ChIP-seq was used to identify target genes, and ChIP, IP and dual luciferase reporter assays were applied to explore the underlying mechanisms. RESULTS CBX8 was significantly overexpressed in chemoresistant CC tissues. In addition, CBX8 could promote stemness and suppress chemosensitivity through LGR5. Mechanistic studies revealed that CBX8 activate the transcription of LGR5 in a noncanonical manner with assistance of Pol II. CBX8 recruited KMT2b to the LGR5 promoter, which maintained H3K4me3 status to promote LGR5 expression. Moreover, m6A methylation participated in the upregulation of CBX8 by maintaining CBX8 mRNA stability. CONCLUSIONS Upon m6A methylation-induced upregulation, CBX8 interacts with KMT2b and Pol II to promote LGR5 expression in a noncanonical manner, which contributes to increased cancer stemness and decreased chemosensitivity in CC. This study provides potential new therapeutic targets and valuable prognostic markers for CC.
Collapse
|
Retracted Publication |
6 |
103 |
22
|
Klose RJ, Cooper S, Farcas AM, Blackledge NP, Brockdorff N. Chromatin sampling--an emerging perspective on targeting polycomb repressor proteins. PLoS Genet 2013; 9:e1003717. [PMID: 23990804 PMCID: PMC3749931 DOI: 10.1371/journal.pgen.1003717] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
|
research-article |
12 |
100 |
23
|
Giudice FS, Pinto DS, Nör JE, Squarize CH, Castilho RM. Inhibition of histone deacetylase impacts cancer stem cells and induces epithelial-mesenchyme transition of head and neck cancer. PLoS One 2013; 8:e58672. [PMID: 23527004 PMCID: PMC3603970 DOI: 10.1371/journal.pone.0058672] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 02/05/2013] [Indexed: 12/30/2022] Open
Abstract
The genome is organized and packed into the nucleus through interactions with core histone proteins. Emerging evidence suggests that tumors are highly responsive to epigenetic alterations that induce chromatin-based events and dynamically influence tumor behavior. We examined chromatin organization in head and neck squamous cell carcinoma (HNSCC) using acetylation levels of histone 3 as a marker of chromatin compaction. Compared to control oral keratinocytes, we found that HNSCC cells are hypoacetylated and that microenvironmental cues (e.g., microvasculature endothelial cells) induce tumor acetylation. Furthermore, we found that chemical inhibition of histone deacetylases (HDAC) reduces the number of cancer stem cells (CSC) and inhibits clonogenic sphere formation. Paradoxically, inhibition of HDAC also induced epithelial-mesenchymal transition (EMT) in HNSCC cells, accumulation of BMI-1, an oncogene associated with tumor aggressiveness, and expression of the vimentin mesenchymal marker. Importantly, we observed co-expression of vimentin and acetylated histone 3 at the invasion front of human HNSCC tumor tissues. Collectively, these findings suggest that environmental cues, such as endothelial cell-secreted factors, modulate tumor plasticity by limiting the population of CSC and inducing EMT. Therefore, inhibition of HDAC may constitute a novel strategy to disrupt the population of CSC in head and neck tumors to create a homogeneous population of cancer cells with biologically defined signatures and predictable behavior.
Collapse
|
Research Support, N.I.H., Extramural |
12 |
99 |
24
|
Schertzer MD, Braceros KCA, Starmer J, Cherney RE, Lee DM, Salazar G, Justice M, Bischoff SR, Cowley DO, Ariel P, Zylka MJ, Dowen JM, Magnuson T, Calabrese JM. lncRNA-Induced Spread of Polycomb Controlled by Genome Architecture, RNA Abundance, and CpG Island DNA. Mol Cell 2019; 75:523-537.e10. [PMID: 31256989 PMCID: PMC6688959 DOI: 10.1016/j.molcel.2019.05.028] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 04/10/2019] [Accepted: 05/17/2019] [Indexed: 01/28/2023]
Abstract
Long noncoding RNAs (lncRNAs) cause Polycomb repressive complexes (PRCs) to spread over broad regions of the mammalian genome. We report that in mouse trophoblast stem cells, the Airn and Kcnq1ot1 lncRNAs induce PRC-dependent chromatin modifications over multi-megabase domains. Throughout the Airn-targeted domain, the extent of PRC-dependent modification correlated with intra-nuclear distance to the Airn locus, preexisting genome architecture, and the abundance of Airn itself. Specific CpG islands (CGIs) displayed characteristics indicating that they nucleate the spread of PRCs upon exposure to Airn. Chromatin environments surrounding Xist, Airn, and Kcnq1ot1 suggest common mechanisms of PRC engagement and spreading. Our data indicate that lncRNA potency can be tightly linked to lncRNA abundance and that within lncRNA-targeted domains, PRCs are recruited to CGIs via lncRNA-independent mechanisms. We propose that CGIs that autonomously recruit PRCs interact with lncRNAs and their associated proteins through three-dimensional space to nucleate the spread of PRCs in lncRNA-targeted domains.
Collapse
|
Research Support, N.I.H., Extramural |
6 |
99 |
25
|
Sun W, Qiao W, Zhou B, Hu Z, Yan Q, Wu J, Wang R, Zhang Q, Miao D. Overexpression of Sirt1 in mesenchymal stem cells protects against bone loss in mice by FOXO3a deacetylation and oxidative stress inhibition. Metabolism 2018; 88:61-71. [PMID: 30318050 DOI: 10.1016/j.metabol.2018.06.006] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/23/2018] [Accepted: 06/17/2018] [Indexed: 12/29/2022]
Abstract
OBJECTIVE B cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) deficiency (Bmi-1-/-) leads to an osteoporotic phenotype with a significant downregulation of Sirt1 protein expression. Sirtuin 1 (Sirt1) haploinsufficiency results in a bone loss by decreased bone formation; however, it is unclear whether Sirt1 overexpression in mesenchymal stem cells (MSCs) plays an anti-osteoporotic role. The aim of the study is to identify whether the overexpression of Sirt1 in MSCs could restore skeletal growth retardation and osteoporosis in Bmi-1 deficient mice. METHODS We used our new generated transgenic mouse model that overexpresses Sirt1 in its MSCs (Sirt1TG) to cross with Bmi-1-/- mice to generate Bmi-1-/- mice with Sirt1 overexpression in MSCs, and compared their skeletal metabolism with those of their Bmi-1-/- and wild-type (WT) littermates (6 mice for each genotype) at 4 weeks of age using imaging, histopathological, immunohistochemical, histomorphometric, cellular, and molecular methods. RESULTS The levels of expression for Sirt1 were noticeably higher in the skeletal tissue of Sirt1TG mice than in those of WT mice. In Comparison to WT mice, the body weight and size, skeletal size, bone volume, osteoblast number, alkaline phosphatase and type I collagen positive areas, osteogenic related gene expression levels were all significantly increased in the Sirt1TG mice. Overexpression of Sirt1 in Bmi-1-/- mouse MSCs resulted in a longer lifespan, improved skeletal growth and significantly increased bone mass by stimulating osteoblastic bone formation and inhibiting osteoclastic bone resorption in the Bmi-1-/- mice, although the defects were not completely restored. Furthermore, Sirt1 overexpression in MSCs reduced the acetylation level of FOXO3a (Forkhead box O3a), increasing levels of expression for FOXO3a and SOD2 (Superoxide dismutase 2) in bony tissue, enhanced osteogenesis and reduced osteogenic cell senescence. We also demonstrated that nicotinamide, a Sirt1 inhibitor, blocks the effect of overexpression of Sirt1 in MSCs on osteogenesis and osteogenic cell senescence. CONCLUSIONS Taken together, these results demonstrate that Sirt1 overexpression in MSCs increased the osteoblastic bone formation and partially restores the defects in skeletal growth and osteogenesis in Bmi-1-/- mice by FOXO3a deacetylation and oxidative stress inhibition. Our data support the proposal that Sirt1 is a target for promoting bone formation as an anabolic approach for the treatment of osteoporosis.
Collapse
|
|
7 |
95 |