OBJECTIVETo study the influence of tumor-associated macrophages (TAMs) on the biological function of SW620 cell.

METHODSMacrophage was induced into M2-type macrophage form with interleukin (IL)-4. CD68, macrophage mannose receptor (MMR), and inducible nitric oxide synthase (iNOS) were analyzed with Western blot. SW620 was co-cultured with TAMs in the Transwell. Cytokines including IL-10, IL-12, IL-23, and tramsforming growth factor-β (TGF-β) were detected with enzyme-linked immunosorbent assay (ELISA). The activity of nuclear factor-κB (NF-κB) in SW620 was analyzed with electrophoretic mobility shift assay (EMSA). The proliferation and apoptosis of SW620 cells after co-cultured with TAM were determined with tetrazolium four nitrogen (XTT) assay and fluorescence activated cell sorting (FACS), respectively. RESULTS IL-4 induced M2 type macrophage expressed CD68 and MMR instead of iNOS. After co-cultured with SW620 for 24 hours and 48 hours, M2 type macrophage secreted higher levels of IL-10 and TGF-β than the pre-culture level (P 0.05). The activity of NF-κB in SW620 decreased by 72% and 75% after 24 hours and 48 hours compared with the pre-culture level, respectively (both P<0.01). The activity of proliferation decreased by 48% and 59% and the apoptotic rates increased by 6.37% and 7.68% and 0.37% after 24 hours and 48 hours (all P<0.01) compared with the pre-culture levels.

CONCLUSIONTAM may inhibit the proliferation and promote the apoptosis of SW620 by suppressing the activity of NF-κB.