Selective estrogen receptor modulator with estrogen does not affect the proliferation and apoptosis of uterine leiomyoma cells

Abstract

Background: The administration of menopausal hormone therapy (MHT) in women with uterine leiomyomas is still debated. The purpose of this article is to study the proliferation and apoptosis of uterine leiomyoma cells under the impact of selective estrogen receptor modulator (SERM) combined with estrogen.

Methods: Primary cultured uterine leiomyoma cells in the perimenopausal period were treated with estrogen (17-beta estradiol) + SERM (raloxifene) as the tissue selective estrogen complex (TSEC) group, while both estrogen + medroxyprogesterone acetate (E+P) and estrogen (E) alone as were used as control groups. The expression of proliferating cell nuclear antigen (PCNA) and B-cell lymphoma-2 (Bcl-2) proteins was assessed by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and western-blot analysis, respectively.

Results: The proliferation in the TSEC group was weaker than the control groups (P<0.001). There was no statistical difference between the TSEC and blank control group on cell proliferation at 72 h (P=0.13). However, there was a significant difference between the other groups (P<0.001). PCNA expression of TSEC was lower than that of the E + P and E groups (P<0.05). There was no statistical difference in the expression of PCNA between the TSEC and blank control groups (P=0.63). Bcl-2 expression of TSEC was lower than that of the E + P and E groups (P<0.05). There was no statistical difference in the expression of Bcl-2 between the TSEC group and the blank control group (P=0.60).

Conclusions: SERM combined with estrogen may have a better safety for perimenopausal women with uterine leiomyoma in MHT.

Keywords: Menopausal hormone therapy (MHT); leiomyoma; tissue selective estrogen complex (TSEC).

Figure 1

Histological identification of uterine leiomyoma. (A) HE staining of uterine leiomyoma (50×). (B) Alpha-Actin staining of uterine leiomyoma (50×). (C) ER staining of uterine leiomyoma (50×).

Figure 2

Cell identification of uterine leiomyoma. (A) Adherence of leiomyoma cells after 24 h culture (100×). (B) Leiomyoma cells were cultured to 48 h (100×). (C) Leiomyoma cells were cultured to 72 h (100×). (D) Leiomyoma cells protruded longer and contacted each other (200×). (E) Alpha-Actin staining of uterine leiomyoma cells (200×). (F) Immunofluorescence staining of alpha-Actin in uterine leiomyoma cells (200×). (G) Immunofluorescence staining of ER-alpha in uterine leiomyoma cells (200×). (H) Immunofluorescence staining of ER-beta in uterine leiomyoma cells (200×).

Figure 3

OD values of different groups in MTT assay. TSEC, E+P, E and blank control groups were cultured for 24, 48 and 72 h respectively, OD mean values of each group were displayed. TSEC group: estrogen (17-beta estradiol) + SERM (raloxifene), E+P group: estrogen (17-beta estradiol) + medroxyprogesterone acetate, E group: estrogen (17-beta estradiol) alone.

Figure 4

The effect of SERM combined with estrogen on the proliferation and apoptosis of uterine leiomyoma cells. (A) Results of PCNA protein band development through Western-Blot. (B) Contrast of PCNA protein gray value. (C) Results of Bcl-2 protein band development through Western-Blot. (D) Contrast of Bcl-2 protein gray value. TSEC group: estrogen (17-beta estradiol) + SERM (raloxifene), E+P group: estrogen (17-beta estradiol) + medroxyprogesterone acetate, E group: estrogen (17-beta estradiol) alone. *, stands for P<0.05, and the difference was statistically significant.