Vitamin D as an effective treatment in human uterine leiomyomas independent of mediator complex subunit 12 mutation

Objective: To study whether vitamin D (VitD) inhibits cell proliferation and Wnt/beta-catenin and transforming growth factor-beta (TGF beta) signaling pathways in uterine leiomyomas independent of mediator complex subunit 12 (MED12) mutation status. Design: Prospective study comparing leiomyoma vs. myometrial tissues and human uterine leiomyoma primary (HULP) cells treated with or without VitD and analyzed by MED12 mutation status. Setting: Hospital and university laboratories. Patient(s): Women with uterine leiomyoma without any treatment (n = 37). Intervention(s): Uterine leiomyoma and myometrium samples were collected from women undergoing surgery because of symptomatic leiomyoma pathology. Main Outcome Measure(s): Analysis of Wnt/beta-catenin and TGF pathways and proliferation by quantitative real-time polymerase chain reaction in leiomyoma and myometrial tissue as well as in VitD-treated HULP cells analyzed by Sanger sequencing. Results: Sequencing data showed that 46% of leiomyomas presented MED12 mutation, whereas no mutations were detected in adjacent myometrium. Expression of Wnt/beta-catenin and TGF beta pathway genes was significantly increased in MED12-mutated leiomyomas compared to matched myometrium; no significant differences were found in wild-type (WT) leiomyomas. In HULP cells, VitD significantly decreased PCNA expression of both MED12-mutated and WT groups. VitD treatment decreased WNT4 and beta-catenin expression in both groups compared to controls, with significance for WNT4 expression in MED12-mutated samples. Similarly, VitD significantly inhibited TGF beta 3 expression in cells from both groups. MMP9 expression also decreased. Conclusion: Despite molecular differences between MED12-mutated and WT leiomyomas, VitD inhibited Wnt/beta-catenin and TGF beta pathways in HULP cells, suggesting VitD as an effective treatment to reduce proliferation and extracellular matrix formation in different molecular subtypes of uterine leiomyomas. ((C) 2020 by American Society for Reproductive Medicine.)

Automated summary

The study showed that vitamin D could inhibit cell proliferation and signaling pathways in different molecular subtypes of uterine leiomyomas, suggesting its potential as an effective treatment.