Inhibition of Hyaluronic Acid Synthesis Decreases Endometrial Cell Attachment, Migration, and Invasion

To characterize the effects of 4-methylumbelliferone (4-MU) on expression of the hyaluronic acid (HA) system and on attachment, migration, and invasion of endometrial epithelial (EECs) and stroma cells (ESCs) to peritoneal mesothelial cells (PMCs), this in vitro study was performed in an Academic Center. De-identified endometrial tissue samples used were from reproductive-aged women. EECs and ESCs isolated from menstrual endometrial biopsies were treated with 4-MU or vehicle. Real-time polymerase chain reaction and western blot were used to assess expression of HA synthases (HAS), hyaluronidase, and standard CD44. Established in vitro assays were used to assess attachment, migration, and invasion with and without treatment with 4-MU. Chi square and Student's t-test were used to analyze the results as appropriate. The addition of 4-MU decreased mRNA and protein expression of HAS 2, HAS 3, and CD44 in EECs and ESCs compared to control. Treatment with 4-MU also decreased attachment, migration, and invasion of EECs and ESCs to PMCs compared to control. 4-MU decreases endometrial cell adhesion, migration, and invasion to PMCs. This effect appears to be mediated by a decrease in HAS 2, HAS 3, and CD44. 4-MU is a potential treatment for endometriosis. Future in vivo studies are needed to evaluate 4-MU as a therapeutic agent for endometriosis.