A selective serotonin 5-HT1B receptor inhibition suppresses cells proliferation and induces apoptosis in human uterine leiomyoma cells.

OBJECTIVE: Uterine leiomyomas (fibroids or myomas) are the most common pelvic tumor in women with about 70% lifetime incidence rate. Currently, the only definitive treatment is surgery, causing undesirable side effects and negative impact on women's quality of life, reproductive ability, and a substantial impact on healthcare costs. Therefore, curative medical treatments are needed to be developed. In this study, we investigated the impact of serotonin receptor 5-HT1B on cell proliferation and survival in human uterine leiomyoma cells (huLM).

STUDY DESIGN: The impact of 5-HT1B receptor on cell proliferation, survival and apoptosis was investigated using a selective 5-HTR1B antagonist SB216641 in huLM cells, utilizing MTS, colony formation assay and Annexin V staining, respectively. Mechanisms of inhibition of cell proliferation, survival and induction of apoptosis were investigated by Western blot analysis after treatment with various doses of HT1B antagonist.

RESULTS: 5-HT1B receptor inhibition leads to a significant decrease in proliferation and colony formation in huLM cells, reduction of cyclin D1 and alpha-smooth muscle actin (α-SMA) expressions and the activity of Mitogen Activated Protein Kinase (MAPK) ERK and Elongation Factor 2 kinase (EF2K) pathways. 5-HT1B receptor blockage also induces apoptotic cell death by inducing cleavage of caspase-8, -9, and -3 and PARP.

CONCLUSION: Our findings show for the first time that 5-HT1B receptor promotes uterine leiomyoma cell survival and proliferation and its inhibition may be a potential therapeutic approach for human uterine leiomyomas. Thus, 5-HT1B expression and antagonists should be further investigated in leiomyoma tumors.