Differential Protumoral Mechanisms Induced by CAFs in Cervical Cancer Cells Occur Independently of 17β-Estradiol Stimulation

Background: E2 is fundamental to the onset and progression of CC. CAFs are the most abundant stromal population in the tumor microenvironment. CAFs have been shown to promote protumoral effects in CC cell lines; however, the effects of E2-stimulated CAFs remain to be explored. Objectives: This study aimed to evaluate whether E2-stimulated CAFs modify the behavior of SiHa and HeLa tumor cells, including their metabolism, ROS production, migration, apoptosis, and gene expression. Methods: Characterization and estrogen receptor expression in primary CAF cultures were evaluated by immunofluorescence. Supernatants from non-stimulated and E2-stimulated CAFs were used to culture CC cells, and mitochondrial metabolism was measured by MTT, ROS production by H2DCFDA, migration using the wound-healing assay, apoptosis by Annexin V assay, and gene expression by next-generation RNA-seq. Results: Stimulation of CC cells with CAFs’ supernatants demonstrated that it influences tumor cells in different ways. In SiHa cells, the metabolic shift was supported by decreased mitochondrial metabolism, increased ROS production, and enhanced gene enrichment for glycolysis and hypoxia responses. On the other hand, in HeLa cells, CAFs enhanced migration and gene enrichment in KRAS signaling, epithelial-mesenchymal transition, and the proinflammatory response, via enrichment of the IL6/JAK/STAT3 signaling pathway, along with the overexpression of cytokines such as IFN-γ, IL-6, and IL-8. Conclusions: CAFs exert protumoral effects by promoting a metabolic shift in SiHa cells or enhancing migration and cytokine secretion in HeLa cells; these effects are independent of E2 stimulation in CAFs.