PYK2 promotes cell proliferation and epithelial-mesenchymal transition in endometriosis by phosphorylating Snail1
Abstract
Background: Endometriosis is associated with decreased endometrial receptivity, lower implantation rates, and reduced ovarian reserve, affecting over 50% of infertile women. Despite its prevalence, the etiology and pathogenesis of endometriosis remain poorly understood. Epithelial-mesenchymal transition (EMT) has been implicated in the progression of endometriosis. Proline-rich tyrosine kinase 2 (PYK2) is a non-receptor tyrosine kinase that influences cell proliferation, survival, and migration by modulating intracellular signaling pathways. PYK2 is known to regulate EMT by affecting the expression of EMT-associated genes through transcription factor modulation. Snail1 is a critical regulator of EMT and is significantly expressed in endometriosis tissues, contributing to the invasive and metastatic capabilities of endometriosis cells. However, the upstream mechanisms regulating Snail1 protein stability in endometriosis are not fully elucidated.
Methods: We identified PYK2 as a non-receptor tyrosine kinase and assessed its expression in endometriosis tissues. Plasmids relevant to our study were constructed. We enrolled 20 patients with laparoscopically confirmed endometriosis, collecting ectopic lesions (14 ovarian endometriotic cysts and 6 deep infiltrating nodules) and matched eutopic endometrial tissues (15 proliferative phase, 5 secretory phase) as controls. Immunohistochemical analysis was performed on all tissue specimens. Human endometrial stromal cells (HESC) were isolated from normal endometrium for in vitro experiments, while ectopic endometrial stromal cells (EESC) were obtained from ectopic lesions. Protein extracts underwent Western blotting and co-immunoprecipitation (Co-IP) for interaction validation. Functional assays assessing proliferation, migration, and invasion were conducted using EESC and 11Z cell lines. Co-IP experiments confirmed the interaction between PYK2 and Snail1. We also evaluated the effect of PYK2 on endometriosis cells in vitro and the impact of VS-6063 on these biological functions. Endometriosis models were established in 20 five-week-old female C57BL/6 mice, randomly divided into experimental (n = 10) and control (n = 10) groups. Statistical analyses were performed using GraphPad Prism 7.0, applying parametric tests for normally distributed data and non-parametric methods for others, with Benjamini-Hochberg correction for multiple comparisons.
Results: PYK2 expression was found to be elevated in endometriosis tissues. It was identified as a novel binding partner of Snail1, enhancing EMT in endometriosis through increased phosphorylation of Snail1. Furthermore, PYK2 was shown to promote the proliferation, migration, and invasion of endometriosis cells while inhibiting decidualization. VS-6063 effectively inhibited the proliferation, migration, and invasion of endometriosis cells in vitro and reduced the growth of endometriotic lesions in vivo.
Conclusions: PYK2 is established as a novel binding partner of Snail1, promoting the development of endometriosis by upregulating Snail1. This interaction presents a promising therapeutic target for endometriosis.
Keywords: EMT; Endometriosis; PYK2; Snail1; VS-6063.