Journal: Oncology Letters
Article Title: Lung squamous cell carcinoma downregulates haptoglobin expression to inhibit M2 macrophage ferroptosis via the hemoglobin-dependent CD163/HO-1 pathway
doi: 10.3892/ol.2026.15558
Figure Lengend Snippet: CM from LUSC cells overexpressing HP leads to ferroptosis in M2 macrophages. (A) THP-1 cells were differentiated into macrophages by treating them with 150 nM PMA for 24 h, followed by culture in fresh RPMI-1640 for 24 h. The macrophages were polarized into M2 macrophages by incubating with IL-4 (20 ng/ml) and IL-13 (20 ng/ml) for 24 h. Flow cytometry was then performed to identify CD163 + CD206 + M2 macrophages. (B) M2 macrophages were cultured with the CM from NCI-H226 and NCI-H520 cells infected with LV- HP or LV-Ctrl in the presence or absence of Hb for 24 h. LDH release was analyzed by ELISA. Treated M2 macrophages were treated as in (B) and flow cytometry was used to detect the proportion of (C) 7-AAD positive cells, as well as the mean fluorescence intensity of (D) FerroOrange and (E) C11-BODIPY. (F) Treated M2 macrophages were observed using transmission electron microscopy. Scale bar, 5 µm. Data are presented as the mean ± SD from five independent experiments and were analyzed using an unpaired t-test or a two-way ANOVA followed by a Tukey's post-hoc multiple comparison analysis. ****P<0.0001. ns, not significant; CM, conditioned media; LUSC, lung squamous cell carcinoma; LDH, lactate dehydrogenase; 7-AAD, 7-aminoactinomycin D; HP, haptoglobin.
Article Snippet: An LDH cytotoxicity assay kit (cat. no. HY-K1090; MedChemExpress) was used to assess LDH levels in the supernatant of LUSC cell lines (NCI-H226 and NCI-H520 cells) and M2 macrophages, according to the manufacturer's protocol.
Techniques: Flow Cytometry, Cell Culture, Infection, Enzyme-linked Immunosorbent Assay, Fluorescence, Transmission Assay, Electron Microscopy, Comparison