Genome-wide transcriptome profiling of primary human uterine leiomyoma cell populations

Uterine leiomyomas (LM) affect up to 80% of all reproductive-age women. LM growth requires progesterone, progesterone receptor (PGR), and the maintenance and proliferation of a small (5%) stem cell population. Stem cell activation and differentiation are driven by DNA methylation and nuclear hormone receptor action, but crosstalk between these mechanisms remains unclear. We performed an integrated analysis of the transcriptome and epigenetic landscape of LM cells at three differentiation stages and the PGR cistrome of whole LM tissue. The PGR-deficient stem cell population harbored a unique methylation landscape, with hypermethylation at the PGR gene locus and PGR-binding regions, which suppressed stem cell responsiveness to progesterone. The DNA methylation inhibitor 5’-Aza upregulated the expression of PGR and its target genes by stimulating PGR recruitment to the targeted gene loci, and significantly depleted the LM stem cell population and its tumor-initiating capacity. We herein provided mechanistic insights via therapeutically accelerating the stem cell differentiation process of a hormone-sensitive tumor.