Long non‐coding RNA cox‐2 prevents immune evasion and metastasis of hepatocellular carcinoma by altering M1/M2 macrophage polarization

Abstract

Macrophages have been shown to demonstrate a high level of plasticity, with the ability to undergo dynamic transition between M1 and M2 polarized phenotypes. We investigate long non-coding RNA (lncRNA) cox-2 in macrophage polarization and the regulatory mechanism functions in hepatocellular carcinoma (HCC). Lipopolysaccharide (LPS) was used to induce RAW264.7 macrophages into M1 type, and IL-4 was to induce RAW264.7 macrophages into M2 type. We selected mouse hepatic cell line Hepal-6 and hepatoma cell line HepG2 for co-incubation with M1 or M2 macrophages. Quantitative real-time PCR was used to detect the expressions of lncRNA cox-2 and mRNAs. ELISA was conducted for testing IL-12 and IL-10 expressions; Western blotting for epithelial mesenchymal transition related factors (E-cadherin and Vimentin). An MTT, colony formation assay, flow cytometry, transwell assay, and stretch test were conducted to test cell abilities. The M1 macrophages had higher lncRNA cox-2 expression than that in the non-polarized macrophages and M2 macrophages. The lncRNA cox-2 siRNA decreased the expression levels of IL-12, iNOS, and TNF-α in M1 macrophages, increased the expression levels of IL-10, Arg-1, and Fizz-1 in M2 macrophages (all P < 0.05). The lncRNA cox-2 siRNA reduces the ability of M1 macrophages to inhibit HCC cell proliferation, invasion, migration, EMT, angiogenesis and facilitate apoptosis while strengthening the ability of M2 macrophages to promote proliferation HCC cell growth and inhibit apoptosis. These findings indicate that lncRNA cox-2 inhibits HCC immune evasion and tumor growth by inhibiting the polarization of M2 macrophages.

Retracted: IL‐6/STAT3 pathway intermediates M1/M2 macrophage polarization during the development of hepatocellular carcinoma

“…Twenty‐four hour later, the supernatant was collected. CD86 (BioLegend, San Diego, CA) as a surface marker of the M1 phenotype macrophages, and CD206 (BioLegend) as a surface marker of the M2 phenotype macrophages were identified by flow cytometry in LPS‐treated macrophages or IL‐4‐treated macrophages . Anti‐IL‐6 antibody (Sigma Chemical Co., St. Louis, Missouri) neutralized by IL‐6 (0.5 μg/mL) was added to RAW264.7 macrophages to react for 48 hours, and then LPS and IL‐4 were supplemented to induce M1 or M2 phenotype macrophages.…”

M2b macrophage polarization and its roles in diseases

“…This study indicated that TCONS_00019715 promotes macrophage polarization to the M1 phenotype. LncRNA COX‐2 is more highly expressed in M1 macrophages and increases the expression levels of IL‐12, iNOS, and TNF‐α . A recent study has shown that lncRNA GAS5 suppresses IFN regulatory factor 4 (IRF4) transcription by binding polycomb repressive complex 2 (PRC2) to inhibit M2 polarization …”

Long noncoding RNAs in autoimmune diseases

“…Another study showed that as a coactivator of NF‐kB, lincRNA‐Cox2 functions as a regulator of the late phase of the primary immune response via modulation of epigenetic chromatin remodeling . Intriguingly, lincRNA‐Cox2 has been shown to modulate both the activation and the repression of distinct classes of immune genes in innate immune cells …”