Luo Xiaoping, Levens Eric, Williams R Stan, Chegini Nasser
Department of Obstetrics and Gynecology, University of Florida, Gainesville, FL, USA.
Hum Reprod. 2006 Jun;21(6):1380-6. doi: 10.1093/humrep/del011. Epub 2006 Feb 17.
Abelson (Abl) interactor 2 (Abi-2) has been considered as a key regulator of cell/tissue structural organization and is differentially expressed in leiomyomas. The objective of this study was to evaluate the expression of Abi-2 in leiomyoma/myometrium during the menstrual cycle and following GnRH analogue (GnRHa) therapy, as well as regulation by transforming growth factor (TGF)-beta1 in leiomyoma and myometrial smooth muscle cells (LSMC and MSMC).
We used real-time PCR, Western blotting and immunohistochemistry to determine the expression of Abi-2 in paired leiomyoma and myometrium (n = 27) from proliferative (n = 8) and secretory (n = 12) phases of the menstrual cycle and from patients who received GnRHa therapy (n = 7). Time-dependent action of TGF-beta1 (2.5 ng/ml) and GnRHa (0.1 microM) on Abi-2 expression was determined in LSMC and MSMC.
Leiomyomas express elevated levels of Abi-2 as compared with myometrium from the proliferative but not the secretory phase of the menstrual cycle, with a significant reduction following GnRHa therapy (P < 0.05). Western blotting showed a similar trend in Abi-2 protein expression in leiomyoma/myometrial tissue extracts, which was immunolocalized in LSMC and MSMC, connective tissue fibroblasts and arterial walls. The expression of Abi-2 in LSMC and MSMC was increased by TGF-beta1 (2.5 ng/ml) and was inhibited by GnRHa (0.1 microM) in a time- and cell-dependent manner, and pretreatment with Smad3 SiRNA and U0126, an MEK-1/2 inhibitor, respectively, reversed their actions.
Based on the menstrual cycle-dependent expression, the influence of GnRHa therapy, and regulation by TGF-beta in LSMC/MSMC, we conclude that Abi-2 may have a key regulatory function in leiomyomas cellular/tissue structural organization during growth and regression.
阿贝尔森（Abl）相互作用蛋白2（Abi-2）被认为是细胞/组织结构的关键调节因子，且在平滑肌瘤中差异表达。本研究的目的是评估月经周期中及促性腺激素释放激素类似物（GnRHa）治疗后，Abi-2在平滑肌瘤/子宫肌层中的表达，以及转化生长因子（TGF）-β1对平滑肌瘤和平滑肌细胞（LSMC和MSMC）中Abi-2的调节作用。
我们使用实时定量PCR、蛋白质免疫印迹法和免疫组织化学来确定Abi-2在月经周期增殖期（n = 8）和分泌期（n = 12）以及接受GnRHa治疗的患者（n = 7）的配对平滑肌瘤和子宫肌层（n = 27）中的表达。在LSMC和MSMC中确定TGF-β1（2.5 ng/ml）和GnRHa（0.1 microM）对Abi-2表达的时间依赖性作用。
与月经周期增殖期而非分泌期的子宫肌层相比，平滑肌瘤中Abi-2表达水平升高，GnRHa治疗后显著降低（P < 0.05）。蛋白质免疫印迹法显示平滑肌瘤/子宫肌层组织提取物中Abi-2蛋白表达有类似趋势，其在LSMC和MSMC、结缔组织成纤维细胞和动脉壁中免疫定位。TGF-β1（2.5 ng/ml）可增加LSMC和MSMC中Abi-2的表达，GnRHa（0.1 microM）则以时间和细胞依赖性方式抑制其表达，分别用Smad3小干扰RNA和MEK-1/2抑制剂U0126预处理可逆转它们的作用。
基于月经周期依赖性表达、GnRHa治疗的影响以及TGF-β在LSMC/MSMC中的调节作用，我们得出结论，Abi-2在平滑肌瘤生长和消退过程中的细胞/组织结构中可能具有关键调节功能。
