Guggulsterone Promotes Nasopharyngeal Carcinoma Cells Exosomal Circfip1L1 to Mediate miR-125a-5p/VEGFA Affecting Tumor Angiogenesis

Background: Nasopharyngeal carcinoma (NPC) is a usual head and neck malignancy. Guggulsterone (GS) has potential in cancer chemoprophylaxis and treatment, but its therapeutic effect on NPC is unknown. We aimed to explore whether GS could promote the secretion of exosomal circFIP1L1 from NPC cells and its regulatory mechanism. Methods: NPC tissues and adjacent tissues were collected from NPC patients. Human nasopharyngeal epithelial cell lines (NP69) and NPC lines (5-8F, CNE1, and HNE1) were used for in vitro experiments. HNE1 cells were treated with GS (20, 40, 60 μmol/L). The expressions of miR-125a-5p and circFIP1L1 were evaluated by qRT-PCR. Cell proliferation and apoptosis abilities were measured by CCK-8 and flow cytometry. HNE1 cell exosomes were extracted and identified, and the levels of VEGFA and VEGFR2 were detected by ELISA. Then miR-125a-5p was knocked down and overexpressed. HUVECs angiogenesis was determined by the tube formation assay. qRT-PCR and Western blot were utilized to evaluate the expressions of VEGFA, MMP-2, MMP-9, and ICAM-1 in HUVECs. Results: miR-125a-5p was highly expressed in NPC tissues and cells. GS promoted the secretion of exosomal circFIP1L1 from HNE1 cells to affect HUVECs proliferation and angiogenesis. Overexpression of miR-125a-5p accelerated HUVECs proliferation and angiogenesis. Knocking down miR-125a- 5p inhibited VEGFA expression. In addition, exosomal circFIP1L1 sponged miR-125a-5p, inhibiting the VEGFA pathway to repress HUVECs angiogenesis. Conclusions: GS promoted exosomal circFIP1L1 in NPC cells to mediate miR-125a-5p/VEGFA axis affecting tumor angiogenesis.