Central lab, Tongren Hospital Affiliated to Wuhan University, The Third Hospital of Wuhan, 241 Pengliuyang Road, Wuchang District, Wuhan, 430060, Hubei, China.
Department of Pharmacy, Tongren Hospital Affiliated to Wuhan University, The Third Hospital of Wuhan, Wuhan, 430060, Hubei, China.
BMC Endocr Disord. 2021 Nov 23;21(1):235. doi: 10.1186/s12902-021-00900-9.
Prolactinoma is a functional pituitary adenoma that secretes excessive prolactin. Dopamine agonists (DAs) such as bromocriptine (BRC) are the first-line treatment for prolactinomas, but the resistance rate is increasing year by year, creating a clinical challenge. Therefore, it is urgent to explore the molecular mechanism of bromocriptine resistance in prolactinomas. Activation of the P38 MAPK pathway affects multidrug resistance in tumours. Our previous studies have demonstrated that inhibiting MAPK14 can suppress the occurrence of prolactinoma, but the role of MAPK11/12/13/14 (p38 MAPK) signalling in dopamine agonist-resistant prolactinomas is still unclear.
A prolactinoma rat model was established to determine the effect of bromocriptine on MAPK11/12/13/14 signalling. DA-resistant GH3 cells and DA-sensitive MMQ cells were used, and the role of MAPK11/12/13/14 in bromocriptine-resistant prolactinomas was preliminarily verified by western blot, RT-qPCR, ELISA, flow cytometry and CCK-8 experiments. The effects of MAPK11 or MAPK14 on bromocriptine-resistant prolactinomas were further verified by siRNA transfection experiments.
Bromocriptine was used to treat rat prolactinoma by upregulating DRD2 expression and downregulating the expression level of MAPK11/12/13/14 in vivo experiments. The in vitro experiments showed that GH3 cells are resistant to bromocriptine and that MMQ cells are sensitive to bromocriptine. Bromocriptine could significantly reduce the expression of MAPK12 and MAPK13 in GH3 cells and MMQ cells. Bromocriptine could significantly reduce the expression of MAPK11, MAPK14, NF-κB p65 and Bcl2 in MMQ but had no effect on MAPK11, MAPK14, NF-κB p65 and Bcl2 in GH3 cells. In addition, knockdown of MAPK11 and MAPK14 in GH3 cells by siRNA transfection reversed the resistance of GH3 cells to bromocriptine, and haloperidol (HAL) blocked the inhibitory effect of bromocriptine on MAPK14, MAPK11, and PRL in MMQ cells. Our findings show that MAPK11 and MAPK14 proteins are involved in bromocriptine resistance in prolactinomas.
Bromocriptine reduces the expression of MAPK11/12/13/14 in prolactinomas, and MAPK11 and MAPK14 are involved in bromocriptine resistance in prolactinomas by regulating apoptosis. Reducing the expression of MAPK11 or MAPK14 can reverse bromocriptine resistance in prolactinomas.
催乳素瘤是一种分泌过量催乳素的功能性垂体腺瘤。多巴胺激动剂（DAs）如溴隐亭（BRC）是催乳素瘤的一线治疗药物，但耐药率逐年上升，这是一个临床挑战。因此，迫切需要探索催乳素瘤对溴隐亭耐药的分子机制。P38 MAPK 通路的激活影响肿瘤的多药耐药性。我们之前的研究表明，抑制 MAPK14 可以抑制催乳素瘤的发生，但 MAPK11/12/13/14（p38 MAPK）信号通路在多巴胺激动剂耐药性催乳素瘤中的作用仍不清楚。
建立催乳素瘤大鼠模型，以确定溴隐亭对 MAPK11/12/13/14 信号通路的影响。使用 DA 耐药 GH3 细胞和 DA 敏感 MMQ 细胞，通过 Western blot、RT-qPCR、ELISA、流式细胞术和 CCK-8 实验初步验证 MAPK11/12/13/14 在溴隐亭耐药性催乳素瘤中的作用。通过 siRNA 转染实验进一步验证 MAPK11 或 MAPK14 对溴隐亭耐药性催乳素瘤的影响。
体内实验表明，溴隐亭通过上调 DRD2 表达和下调 MAPK11/12/13/14 的表达水平来治疗大鼠催乳素瘤。体外实验表明，GH3 细胞对溴隐亭耐药，而 MMQ 细胞对溴隐亭敏感。溴隐亭可显著降低 GH3 细胞和 MMQ 细胞中 MAPK12 和 MAPK13 的表达。溴隐亭可显著降低 MMQ 中 MAPK11、MAPK14、NF-κB p65 和 Bcl2 的表达，但对 GH3 细胞中 MAPK11、MAPK14、NF-κB p65 和 Bcl2 无影响。此外，通过 siRNA 转染下调 GH3 细胞中的 MAPK11 和 MAPK14 可逆转 GH3 细胞对溴隐亭的耐药性，而氟哌啶醇（HAL）阻断了溴隐亭对 MMQ 细胞中 MAPK14、MAPK11 和 PRL 的抑制作用。我们的研究结果表明，MAPK11 和 MAPK14 蛋白参与了催乳素瘤对溴隐亭的耐药性。
溴隐亭降低催乳素瘤中 MAPK11/12/13/14 的表达，MAPK11 和 MAPK14 通过调节细胞凋亡参与催乳素瘤对溴隐亭的耐药性。降低 MAPK11 或 MAPK14 的表达可以逆转催乳素瘤对溴隐亭的耐药性。
