15-Deoxy-Δ-12,14-Prostaglandin J2 Represses Immune Escape of Lung Adenocarcinoma by Polarizing Macrophages Through Epidermal Growth Factor Receptor/Ras/Raf Pathway.

Lung adenocarcinoma (LUAD) is a widespread and deadly form of cancer. Prostaglandin 15-deoxy-Δ-12,14-prostaglandin J2 (15d-PGJ2) possesses antioxidant, anti-inflammatory, and anticancer properties. However, it is unclear whether this effect on LUAD progression stems from its ability to influence macrophage polarization. By utilizing 3- (4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, colony formation, transwell assays, and enzyme linked immunosorbent assay (ELISA), we investigated how 15d-PGJ2 affects A549 cell viability, proliferation, apoptosis, and invasion, as well as levels of interleukin (IL)-4, IL-13, and IL-17. Human monocytic cell line THP-1 was induced into M2 macrophages using phorbol 12-myristate 13-acetate and IL-4/IL-13, followed by treatment with 15d-PGJ2. The study employed flow cytometry to observe the polarization of macrophages, quantitative reverse transcription polymerase chain reaction (qRT-PCR) to identify epidermal growth factor receptor (EGFR) expression, western blot for identifying expression of macrophage marker proteins, and examining EGFR/rat sarcoma (Ras)/rapidly accelerated fibrosarcoma (Raf) activation. In a coculture setup, CD8+ T cells were shown to have a proliferation capacity by carboxifluorescein diacetate succinimidyl ester (CFSE), a killing ability by lactate dehydrogenase, and an analysis of their interferon gamma and tumor necrosis factor alpha levels by ELISA. 15d-PGJ2 reduced invasion capacity and expression of inflammatory cytokines, lowered A549 cell viability in a dose-dependent way, and promoted apoptosis. 15d-PGJ2 facilitated the transition of M2 macrophages to the M1 type, inhibited Ras/Raf pathway activation, reduced EGFR expression in macrophages, and stimulated CD8+ T cells to enhance anti-tumor immunity. 15d-PGJ2 repressed M2 macrophage polarization and LUAD immune evasion by targeting the EGFR/Ras/Raf pathway in macrophages.