Stearoyl–coenzyme A desaturase enhances cell survival in human uterine leiomyoma

Objective

Stearoyl-CoA desaturase (SCD1) is an enzyme that catalyzes the conversion of saturated delta-9 fatty acids to monounsaturated fatty acids. SCD1 is highly expressed in various cancers and facilitates cancer cell survival, tumor growth, and metastasis. This study aimed to assess SCD1 expression and function in uterine leiomyoma and matched myometrial tissue and evaluate the impact of SCD1 inhibition on leiomyoma cell viability and apoptosis.

Design

Gene set enrichment analysis was performed to determine whether lipid metabolism pathways are dysregulated in leiomyoma. To assess the function of SCD1, primary leiomyoma and myometrial cells, as well as a CRISPR-engineered leiomyoma-relevant MED12 mutant human uterine smooth muscle (UtSM) cell line, were treated with SCD1 small interfering RNA or a small molecule inhibitor of SCD1, CAY10566. Cell viability and apoptosis assays, real-time quantitative polymerase chain reaction, and immunoblot analyses were performed to evaluate cell function in response to treatment.

Subjects

Leiomyoma and myometrial tissues were obtained from premenopausal individuals designated female at birth (n = 30) undergoing myomectomy or hysterectomy.

Exposure

SCD1 inhibition by small interfering RNA and CAY10566 treatment.

Main Outcome Measures

Messenger RNA (mRNA) and protein levels and cell viability and apoptosis.

Results

Gene set enrichment analysis revealed that the cholesterol homeostasis pathway was significantly different in leiomyoma vs. adjacent myometrial tissues. Among the genes in this pathway, SCD1 mRNA levels were found to be significantly higher in leiomyoma than in matched myometrium. SCD1 inhibition by small interfering RNA or CAY10566 decreased antiapoptotic BCL2 mRNA and protein levels and cell viability in primary leiomyoma but not myometrial cells. SCD1 protein levels were significantly higher in the mutant MED12 UtSM cell line than in the wild-type MED12 UtSM cell line. CAY10566 treatment specifically decreased cell viability and increased apoptosis in mutant MED12 UtSM cells, with increased protein levels of cleaved caspase 3, cleaved PARP, and DDIT3 in mutant MED12 UtSM but not in wild-type MED12 UtSM cells.

Conclusion

SCD1, an enzyme involved in lipid homeostasis, may play an important role in promoting leiomyoma growth and represents a novel target for the treatment of leiomyoma.