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Project description:Purpose: Dysregulation of histone H3 arginine (R) methylation is still unknown in primary cancer including gastric cancer (GC), although PRMT6 plays a role in asymmetric dimethylation at H3R2 (H3R2me2as) in cancer cells. The objective is to clarify biological and molecular roles of H3R2me2as-PRMT6 pathway in GC. Experimental Design: We assessed H3R2me2as and PRMT6 levels in 133 primary GC tissues by immunohistochemistry. We analyzed biological functions of PRMT6 in GC cell lines using a lentivirus overexpression and CRISPR/Cas9-based knockout of PRMT6 systems. Results: Increased H3R2me2as was found in 68 GC (51.1%) cases and independently correlated with poor prognosis. PRMT6 was overexpressed in 70 (52.6%) GC, which strongly correlated with the H3R2me2as levels (P<0.001). PRMT6 overexpression in GC cells enhanced global H3R2me2as levels, cell invasiveness in vitro, while PRMT6-knockout GC cells suppressed these effects. PRMT6 knockout also impaired tumorigenicity in vivo. Microarray and ChIP assays demonstrated that PRMT6-knockout GC cells decreased the H3R2me2as levels at the promoter regions of PCDH7, SCD and IGFBP5, resulting in up-reregulation of their gene expression. PRMT6 recruited at the regions of PCDH7 and SCD in the PRMT6-overexpressed cells. Knockdown of tumor suppressor PCDH7 in PRMT6-knockout GC cells elevated cell migration and invasion. PRMT6 expression inversely correlated with PCDH7 expression in primary GC (P=0.021). Conclusions: H3R2me2as is a strong prognostic indicator of GC patients. Global and gene-specific H3R2me2as are maintained by PRMT6. PRMT6-overexpressed GC cells may acquire invasiveness through direct inhibition of PCDH7 by increasing H3R2me2as activity. Thus, PRMT6-H3R2me2as pathway is a promising new therapeutic target in GC.
2020-04-16 | GSE113189 | GEO
Project description:Purpose: Dysregulation of histone H3 arginine (R) methylation is still unknown in primary cancer including gastric cancer (GC), although PRMT6 plays a role in asymmetric dimethylation at H3R2 (H3R2me2as) in cancer cells. The objective is to clarify biological and molecular roles of H3R2me2as-PRMT6 pathway in GC. Experimental Design: We assessed H3R2me2as and PRMT6 levels in 133 primary GC tissues by immunohistochemistry. We analyzed biological functions of PRMT6 in GC cell lines using a lentivirus overexpression and CRISPR/Cas9-based knockout of PRMT6 systems. Results: Increased H3R2me2as was found in 68 GC (51.1%) cases and independently correlated with poor prognosis. PRMT6 was overexpressed in 70 (52.6%) GC, which strongly correlated with the H3R2me2as levels (P<0.001). PRMT6 overexpression in GC cells enhanced global H3R2me2as levels, cell invasiveness in vitro, while PRMT6-knockout GC cells suppressed these effects. PRMT6 knockout also impaired tumorigenicity in vivo. Microarray and ChIP assays demonstrated that PRMT6-knockout GC cells decreased the H3R2me2as levels at the promoter regions of PCDH7, SCD and IGFBP5, resulting in up-reregulation of their gene expression. PRMT6 recruited at the regions of PCDH7 and SCD in the PRMT6-overexpressed cells. Knockdown of tumor suppressor PCDH7 in PRMT6-knockout GC cells elevated cell migration and invasion. PRMT6 expression inversely correlated with PCDH7 expression in primary GC (P=0.021). Conclusions: H3R2me2as is a strong prognostic indicator of GC patients. Global and gene-specific H3R2me2as are maintained by PRMT6. PRMT6-overexpressed GC cells may acquire invasiveness through direct inhibition of PCDH7 by increasing H3R2me2as activity. Thus, PRMT6-H3R2me2as pathway is a promising new therapeutic target in GC.
2020-04-16 | GSE113188 | GEO
Project description:Asymmetric demethylation at histone H3 arginine 2 by PRMT6 in gastric cancer progression
| PRJNA450398 | ENA
Project description:Asymmetric demethylation at histone H3 arginine 2 by PRMT6 in gastric cancer progression (AGS cell line)
| PRJNA450399 | ENA
Project description:Asymmetric demethylation at histone H3 arginine 2 by PRMT6 in gastric cancer progression (NUGC3 cell line)
| PRJNA450400 | ENA
Project description:The arginine methyltransferase PRMT6 (protein arginine methyltransferase 6) has been shown recently to regulate DNA repair and gene expression. As arginine methylation of histones is an important mechanism in transcriptional regulation, we asked whether PRMT6 possesses activity toward histones. We show here that PRMT6 methylates histone H3 at R2 and histones H4/H2A at R3 in vitro. Overexpression and knockdown analysis identify PRMT6 as the major H3 R2 methyltransferase in vivo. We find that H3 R2 methylation inhibits H3 K4 trimethylation and recruitment of WDR5, a subunit of the MLL (mixed lineage leukemia) K4 methyltransferase complex, to histone H3 in vitro. Upon PRMT6 overexpression, transcription of Hox genes and Myc-dependent genes, both well-known targets of H3 K4 trimethylation, decreases. This transcriptional repression coincides with enhanced occurrence of H3 R2 methylation and PRMT6 as well as reduced levels of H3 K4 trimethylation and MLL1/WDR5 recruitment at the HoxA2 gene. Upon retinoic acid-induced transcriptional activation of HoxA2 in a cell model of neuronal differentiation, PRMT6 recruitment and H3 R2 methylation are diminished and H3 K4 trimethylation increases at the gene. Our findings identify PRMT6 as the mammalian methyltransferase for H3 R2 and establish the enzyme as a crucial negative regulator of H3 K4 trimethylation and transcriptional activation.
| S-EPMC2113036 | biostudies-literature
Project description:Melanoma antigen (MAGE)-encoding genes are expressed in various tumour types via demethylation of their promoter CpG islands, which are silent in all non-neoplastic tissues except for the testis and placenta. The clinicopathological significance of demethylation of MAGE genes in gastric carcinoma is not known. We investigated the promoter methylation status of MAGE-A1 and -A3 in 10 gastric cancer cell lines and in surgical specimens from 84 gastric cancer patients by methylation-specific PCR (MSP). Expression of MAGE-A1 and -A3 in the 10 gastric cancer cell lines was also investigated by RT-PCR. Any correlation between the methylation status of the MAGE promoters and clinicopathological characteristics of the gastric cancer patients was then assessed. Eight of the 10 gastric cancer cell lines showed demethylation of both MAGE-A1 and -A3, and the remaining two cell lines did either of MAGE-A1 or -A3. Expression of MAGE-A1 and -A3 was confirmed in seven and nine of the 10 gastric cancer cell lines, respectively. The MAGE-A1 and -A3 promoters were demethylated in 29% (25 out of 84) and 66% (56 out of 84) of the gastric tumour specimens, respectively. Demethylation of both MAGE-A1 and -A3 promoters (n=22) was found more frequently in gastric cancer patients in advanced clinical stages (P=0.0035), and these patients also exhibited a higher incidence of lymph node metastasis (P=0.0007) compared to those patients without demethylation (n=25). Furthermore, demethylation patients tended to have a worse prognosis, although this difference was not statistically significant (P=0.183). Demethylation of MAGE-A1 and -A3 occurs during progressive stages of gastric cancer, and may be associated with aggressive biological behaviour of gastric cancer.
| S-EPMC2410179 | biostudies-other
Project description:Histone H3 lysine 4 trimethylation (H3K4me3) is a hallmark of transcription initiation, but how H3K4me3 is demethylated during gene repression is poorly understood. Jhd2, a JmjC domain protein, was recently identified as the major H3K4me3 histone demethylase (HDM) in Saccharomyces cerevisiae. Although JHD2 is required for removal of methylation upon gene repression, deletion of JHD2 does not result in increased levels of H3K4me3 in bulk histones, indicating that this HDM is unable to demethylate histones during steady-state conditions. In this study, we showed that this was due to the negative regulation of Jhd2 activity by histone H3 lysine 14 acetylation (H3K14ac), which colocalizes with H3K4me3 across the yeast genome. We demonstrated that loss of the histone H3-specific acetyltransferases (HATs) resulted in genome-wide depletion of H3K4me3, and this was not due to a transcription defect. Moreover, H3K4me3 levels were reestablished in HAT mutants following loss of JHD2, which suggested that H3-specific HATs and Jhd2 serve opposing functions in regulating H3K4me3 levels. We revealed the molecular basis for this suppression by demonstrating that H3K14ac negatively regulated Jhd2 demethylase activity on an acetylated peptide in vitro. These results revealed the existence of a general mechanism for removal of H3K4me3 following gene repression.
| S-EPMC3494965 | biostudies-literature
Project description:Tri- and dimethylations of histone H3K9 (H3K9me3/2) and H3K27 (H3K27me3/2), both situated in the "A-R-Kme-S" sequence motif, mediate transcriptional repression of distinct genomic regions. H3K9me3/2 mainly governs constitutive heterochromatin formation, while H3K27me3/2 represses key developmental genes. The mechanisms by which histone-modifying enzymes selectively regulate the methylation states of H3K9 and H3K27 are poorly understood. Here we report the crystal structures of the catalytic fragment of UTX/KDM6A, an H3K27me3/2-specific demethylase, in the free and H3 peptide-bound forms. The catalytic jumonji domain binds H3 residues 25-33, recognizing H3R26, H3A29, and H3P30 in a sequence-specific manner, in addition to H3K27me3 in the catalytic pocket. A novel zinc-binding domain, conserved within the KDM6 family, binds residues 17-21 of H3. The zinc-binding domain changes its conformation upon H3 binding, and thereby recognizes the H3L20 side chain via a hydrophobic patch on its surface, which is inaccessible in the H3-free form. Mutational analyses showed that H3R17, H3L20, H3R26, H3A29, H3P30, and H3T32 are each important for demethylation. No other methyllysines in the histone tails have the same set of residues at the corresponding positions. Thus, we clarified how UTX discriminates H3K27me3/2 from the other methyllysines with distinct roles, including the near-cognate H3K9me3/2, in histones.
| S-EPMC3219231 | biostudies-literature
Project description:Histone demethylation by Jumonji-family proteins is coupled with the decarboxylation of ?-ketoglutarate (?KG) to yield succinate, prompting hypotheses that their activities are responsive to levels of these metabolites in the cell. Consistent with this paradigm we show here that the Saccharomyces cerevisiae Jumonji demethylase Jhd2 opposes the accumulation of H3K4me3 in fermenting cells only when they are nutritionally manipulated to contain an elevated ?KG/succinate ratio. We also find that Jhd2 opposes H3K4me3 in respiratory cells that do not exhibit such an elevated ?KG/succinate ratio. While jhd2? caused only limited gene expression defects in fermenting cells, transcript profiling and physiological measurements show that JHD2 restricts mitochondrial respiratory capacity in cells grown in non-fermentable carbon in an H3K4me-dependent manner. In association with these phenotypes, we find that JHD2 limits yeast proliferative capacity under physiologically challenging conditions as measured by both replicative lifespan and colony growth on non-fermentable carbon. JHD2's impact on nutrient response may reflect an ancestral role of its gene family in mediating mitochondrial regulation.
| S-EPMC5126570 | biostudies-literature