Secretome of senescent hepatoma cells modulate macrophage polarization and neutrophil extracellular traps formation

Presence of dysfunctional senescent hepatocyte is a hallmark feature of cirrhosis. We now report the presence of senescent hepatocytes (p21 and p53 positive) in vicinity of infiltrated immune cells in hepatocellular carcinoma. Hence, we checked if senescent cells can alter fate of macrophage polarization and neutrophil extracellular trap (NETs) formation. Using an in vitro assay, senescence was induced in hepatoma cells (HepG2 and Huh7 cells) by doxorubicin treatment and senescent cell showed secretory phenotype with strong expression of cytokines (IL1{beta}, IL6, IL8 and IL13) as evaluated by Flow cytometry. The senescent secretome from hepatoma cells induced macrophage differentiation predominantly with M2 markers (CD80, CD86) while that of non-senescent cell induced M1 phenotype (CD163, CD206) as analysed by flow cytometry. Human hepatocellular carcinoma harbouring senescent hepatocytes showed presence of M2 macrophages, while M1 macrophages were predominant in non-tumorous region. Additionally, the senescent secretome from Huh7 cells (p53mut) enhanced the NETs formation, while HepG2 (p53+/+) secretome had an inhibitory affect In conclusion, the "pro-inflammatory" senescent secretome drives non-inflammatory type M2 macrophage polarization and modulate neutrophil traps thereby modulating the microenvironment towards tumor promotion. Targeting senescent hepatocyte secretome appears a promising therapeutic target in liver cancer in future. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=126 SRC="FIGDIR/small/423905v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1df4256org.highwire.dtl.DTLVardef@7c4f53org.highwire.dtl.DTLVardef@13bfe80org.highwire.dtl.DTLVardef@1c1c4b5_HPS_FORMAT_FIGEXP M_FIG Work Highlight (Diagrammatic Representation). C_FIG