Steroid hormones and hormone antagonists regulate the neural marker neurotrimin in uterine leiomyoma

Objective: To characterize the role of steroid hormone and antihormone exposure on neurotrimin (NTM) expression in human leiomyoma and myometrial tissue and cells.

Design: Laboratory study of placebo and ulipristal acetate (UPA)-treated patient tissue. In vitro assessment of immortalized myometrial and leiomyoma cell lines after hormone and antihormone exposure.

Setting: Academic research center.

Patient(s): Not applicable.

Interventions(s): Exposure of leiomyoma cell lines to 17β-E₂, medroxyprogesterone acetate (MPA), UPA, and fulvestrant.

Main outcome measure(s): Messenger RNA expression quantified with the use of RNASeq analysis and quantitative real-time polymerase chain reaction (qRT-PCR). Protein levels quantified by means of Western blot analysis. Immunohistochemistry (IHC) on placebo- and UPA-treated patient uterine tissue specimens.

Result(s): Expression of NTM in human uterine leiomyoma specimens according to RNASeq was increased compared with myometrium (5.22 ± 0.57-fold), which was confirmed with the use of qRT-PCR (1.95 ± 0.05). Furthermore, NTM protein was elevated in leiomyoma tissue compared with matched myometrium (2.799 ± 0.575). IHC revealed increased staining intensity in leiomyoma surgical specimens compared with matched myometrium of placebo patients. Western blot analysis in immortalized leiomyoma cell lines demonstrated an up-regulation of NTM protein expression (2.4 ± 0.04). Treatment of leiomyoma cell lines with 17β-E₂ yielded a 1.98 ± 0.11-fold increase in NTM protein expression; however, treatment with fulvestrant showed no significant change compared with control. Leiomyoma cell lines demonstrated a 1.91 ± 0.97-fold increase in NTM protein expression after progesterone treatment. RNASeq analysis demonstrated a reduced expression in patient leiomyoma after UPA treatment (0.75 ± 0.14). Treatment of leiomyoma cells with UPA demonstrated a reduced total NTM protein amount (0.54 ± 0.31) in patients, which was confirmed with the use of IHC (UPA10 147.2 ± 9.40, UPA20 182.8 ± 8.98). In vitro studies with UPA treatment revealed a concentration-dependent effect that supported these findings.

Conclusion(s): NTM, a neural cell adhesion molecule, is increased in leiomyoma compared with myometrium in patient tissue and in vitro models after estrogen and progesterone treatment. Down-regulation of expression occurs after UPA treatment, but not after fulvestrant exposure.

Clinical trial registration number: NCT00290251.