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Project description:Uterine leiomyomas cause heavy menstrual bleeding, anemia, and pregnancy loss in millions of women worldwide. Driver mutations in the transcriptional mediator complex subunit 12 (MED12) gene in uterine myometrial cells initiate 70% of leiomyomas that grow in a progesterone-dependent manner. We showed a distinct chromatin occupancy landscape of MED12 in mutant MED12 (mut-MED12) versus WT-MED12 leiomyomas. Integration of cistromic and transcriptomics data identified tryptophan 2,3-dioxygenase (TDO2) as the top mut-MED12 target gene that was significantly upregulated in mut-MED12 leiomyomas when compared with adjacent myometrium and WT-MED12 leiomyomas. TDO2 catalyzes the conversion of tryptophan to kynurenine, an aryl hydrocarbon receptor (AHR) ligand that we confirmed to be significantly elevated in mut-MED12 leiomyomas. Treatment of primary mut-MED12 leiomyoma cells with tryptophan or kynurenine stimulated AHR nuclear translocation, increased proliferation, inhibited apoptosis, and induced AHR-target gene expression, whereas blocking the TDO2/kynurenine/AHR pathway by siRNA or pharmacological treatment abolished these effects. Progesterone receptors regulated the expression of AHR and its target genes. In vivo, TDO2 expression positively correlated with the expression of genes crucial for leiomyoma growth. In summary, activation of the TDO2/kynurenine/AHR pathway selectively in mut-MED12 leiomyomas promoted tumor growth and may inform the future development of targeted treatments and precision medicine.
| S-EPMC10561729 | biostudies-literature
Project description:Uterine leiomyoma (LM) is the most common tumor in women. Estrogen and progesterone, via their receptors ERα and PR, play essential roles in LM growth. Mediator complex subunit 12 (MED12) mutations occur in 70% of all LM and are thought to drive tumor growth in a steroid hormone-dependent manner; however, the mechanisms remain unclear. Here, we performed ChIP-seq (ERα, PR, and MED12) and RNA-seq on LM expressing mutant MED12 (mut-MED12) or wild-type MED12 and matched myometrium. Mut-MED12 altered PR and chromatin interaction landscapes, with significant PR-binding site loss in proximal promoter regions in mut-MED12 LM. Integration of cistrome and transcriptome data identified tryptophan 2,3-dioxygenase (TDO2) as a PR and MED12 target gene, which was aberrantly upregulated in mut-MED12 LM. Kynurenine, the catabolic product of TDO2, was significantly elevated in mut-MED12 LM. Tryptophan or kynurenine treatment of primary LM cells activated the aryl hydrocarbon receptor (AHR) pathway, increased cell proliferation, and inhibited apoptosis; blocking the TDO2-kynurenine-AHR pathway by siRNA knockdown or pharmacologic inhibition abolished these effects. Mut-MED12 LM cells showed higher sensitivity to these treatments. These findings suggest that activation of the TDO2-kynurenine-AHR pathway in mut-MED12 LM induces tumor growth, and may inform the development of targeted treatments and precision medicine in LM.
2023-05-01 | GSE204969 | GEO
Project description:Uterine leiomyoma (LM) is the most common tumor in women. Estrogen and progesterone, via their receptors ERα and PR, play essential roles in LM growth. Mediator complex subunit 12 (MED12) mutations occur in 70% of all LM and are thought to drive tumor growth in a steroid hormone-dependent manner; however, the mechanisms remain unclear. Here, we performed ChIP-seq (ERα, PR, and MED12) and RNA-seq on LM expressing mutant MED12 (mut-MED12) or wild-type MED12 and matched myometrium. Mut-MED12 altered PR and chromatin interaction landscapes, with significant PR-binding site loss in proximal promoter regions in mut-MED12 LM. Integration of cistrome and transcriptome data identified tryptophan 2,3-dioxygenase (TDO2) as a PR and MED12 target gene, which was aberrantly upregulated in mut-MED12 LM. Kynurenine, the catabolic product of TDO2, was significantly elevated in mut-MED12 LM. Tryptophan or kynurenine treatment of primary LM cells activated the aryl hydrocarbon receptor (AHR) pathway, increased cell proliferation, and inhibited apoptosis; blocking the TDO2-kynurenine-AHR pathway by siRNA knockdown or pharmacologic inhibition abolished these effects. Mut-MED12 LM cells showed higher sensitivity to these treatments. These findings suggest that activation of the TDO2-kynurenine-AHR pathway in mut-MED12 LM induces tumor growth, and may inform the development of targeted treatments and precision medicine in LM.
2023-05-01 | GSE204968 | GEO
Project description:MED12 Mutation Activates Tryptophan-Kynurenine-AHR pathway and Promotes Cell Growth in Human Uterine Leiomyoma.
| PRJNA842908 | ENA
Project description:MED12 Mutation Activates Tryptophan-Kynurenine-AHR pathway and Promotes Cell Growth in Human Uterine Leiomyoma [RNA-seq]
| PRJNA842912 | ENA
Project description:MED12 mutation activates the tryptophan/kynurenine/AHR pathway to promote growth of uterine leiomyomas
| PRJNA842913 | ENA
Project description:Uterine leiomyoma is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. Epidemiological studies consistently indicate a correlation between leiomyoma development and exposure to endocrine-disrupting chemical phthalates, especially di-(2-ethylhexyl) phthalate (DEHP); however, the underlying mechanisms are unknown. Here, among the most commonly encountered phthalate metabolites, we found the strongest association between the urine levels of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), the principal DEHP metabolite, and the risk of uterine leiomyoma diagnosis (n = 712 patients). The treatment of primary leiomyoma and smooth muscle cells (n = 29) with various mixtures of phthalate metabolites, at concentrations equivalent to those detected in urine samples, significantly increased cell viability and decreased apoptosis. MEHHP had the strongest effects on both cell viability and apoptosis. MEHHP increased cellular tryptophan and kynurenine levels strikingly and induced the expression of the tryptophan transporters SLC7A5 and SLC7A8, as well as, tryptophan 2,3-dioxygenase (TDO2), the key enzyme catalyzing the conversion of tryptophan to kynurenine that is the endogenous ligand of aryl hydrocarbon receptor (AHR). MEHHP stimulated nuclear localization of AHR and up-regulated the expression of CYP1A1 and CYP1B1, two prototype targets of AHR. siRNA knockdown or pharmacological inhibition of SLC7A5/SLC7A8, TDO2, or AHR abolished MEHHP-mediated effects on leiomyoma cell survival. These findings indicate that MEHHP promotes leiomyoma cell survival by activating the tryptophan-kynurenine-AHR pathway. This study pinpoints MEHHP exposure as a high-risk factor for leiomyoma growth, uncovers a mechanism by which exposure to environmental phthalate impacts leiomyoma pathogenesis, and may lead to the development of novel druggable targets.
| S-EPMC9704719 | biostudies-literature
Project description:Uterine leiomyomas (fibroids) are common benign tumors in women. The tryptophan metabolism through the kynurenine pathway plays important roles in tumorigenesis in general. Leiomyomas expressing mutated mediator complex subunit 12 (mut-MED12) were reported to contain significantly decreased tryptophan levels; the underlying mechanism and the role of the tryptophan metabolism-kynurenine pathway in leiomyoma tumorigenesis, however, remain unknown. We here assessed the expression and regulation of the key enzymes that metabolize tryptophan. Among these, the tissue mRNA levels of tryptophan 2,3-dioxygenase (TDO2), the rate limiting enzyme of tryptophan metabolism through the kynurenine pathway, was 36-fold higher in mut-MED12 compared to adjacent myometrium (P < 0.0001), and 14-fold higher compared to wild type (wt)-MED12 leiomyoma (P < 0.05). The mRNA levels of other tryptophan metabolizing enzymes, IDO1 and IDO2, were low and not significantly different, suggesting that TDO2 is the key enzyme responsible for reduced tryptophan levels in mut-MED12 leiomyoma. R5020 and medroxyprogesterone acetate (MPA), two progesterone agonists, regulated TDO2 gene expression in primary myometrial and leiomyoma cells expressing wt-MED12; however, this effect was absent or blunted in leiomyoma cells expressing G44D mut-MED12. These data suggest that MED12 mutation may alter progesterone-mediated TDO2 expression in leiomyoma, leading to lower levels of tryptophan in mut-MED12 leiomyoma. This highlights that fibroids can vary widely in their response to progesterone as a result of mutation status and provides some insight for understanding the effect of tryptophan-kynurenine pathway on leiomyoma tumorigenesis and identifying targeted interventions for fibroids based on their distinct molecular signatures.
| S-EPMC8863695 | biostudies-literature
Project description:Uterine leiomyomas, or fibroids, are the most common human tumors. Based on histopathology, they can be divided into common leiomyomas and various relatively rare subtypes that mimic malignancy in one or more aspects. Recently, we showed that exon 2 of mediator complex subunit 12 (MED12) is mutated in up to 70% of common fibroids. To investigate the frequency of MED12 exon 2 mutations in histopathological uterine leiomyoma variants, we screened altogether 206 lesions, including 69 histopathologically common leiomyomas, 59 cellular (23 cellular and 36 highly cellular), 18 atypical and 26 mitotically active leiomyomas, as well as 34 uterine fibroid samples from 14 hereditary leiomyomatosis and renal cell cancer patients with a heterozygous germ line mutation in fumarate hydratase (FH). The uterine leiomyoma variants harbored MED12 exon 2 mutations significantly less frequently than common leiomyomas (P=2.93 × 10(-8)). In all, 6 mutations were detected among cellular fibroids (6/67; 8.96%), 3 among atypical fibroids (3/18; 16.67%) and 10 among mitotically active fibroids (10/26; 38.46%). Only mitotically active fibroids displayed a mutation frequency that was not statistically different from common leiomyomas (P=0.11). Three MED12 exon 2 mutations were detected among 34 tumors with a heterozygous germ line FH mutation (P=5.28 × 10(-7)). None of these tumors displayed biallelic inactivation of FH. Our results suggest that MED12 mutation positivity is a key characteristic of common leiomyomas. Cellular and atypical fibroids, in particular, may arise through different molecular mechanisms. The results also propose that MED12 and biallelic FH mutations may be mutually exclusive.
| S-EPMC3798840 | biostudies-literature
Project description:Somatic mutations in exon 2 of the RNA polymerase II transcriptional Mediator subunit MED12 occur at very high frequency (?70%) in uterine leiomyomas. However, the influence of these mutations on Mediator function and the molecular basis for their tumorigenic potential remain unknown. To clarify the impact of these mutations, we used affinity-purification mass spectrometry to establish the global protein-protein interaction profiles for both wild-type and mutant MED12. We found that uterine leiomyoma-linked mutations in MED12 led to a highly specific decrease in its association with Cyclin C-CDK8/CDK19 and loss of Mediator-associated CDK activity. Mechanistically, this occurs through disruption of a MED12-Cyclin C binding interface that we also show is required for MED12-mediated stimulation of Cyclin C-dependent CDK8 kinase activity. These findings indicate that uterine leiomyoma-linked mutations in MED12 uncouple Cyclin C-CDK8/19 from core Mediator and further identify the MED12/Cyclin C interface as a prospective therapeutic target in CDK8-driven cancers.
| S-EPMC4041330 | biostudies-literature