肿瘤相关巨噬细胞中SHP-1靶向SP1/DNMT1信号通路促进乳腺癌进展的机制OA

Objective:The aim of this study was to investigate the role of Src-homology domain 2 containing protein tyrosine phos-phatase-1(SHP-1)expression in macrophages in breast cancer and its potential mechanisms.Methods:GEO database was used for bioinformatics analysis,and a nude mouse tumor model was constructed to detect the effects of SHP-1 and Spi-1 proto-oncogene(PU.1)overexpression in macrophages on tumor progression.THP-1 cells were stimulated under different conditions and divided into six groups:NC group,SHP-1-OE group,NC+SP1 inhibitor group,SHP-1-OE+SP1 inhibitor group,NC+SP1 inhibitor+SYK inhibitor group and SHP-1-OE+SP1 inhibitor+SYK inhibitor group.These THP-1 cells were co-cultured with breast cancer MCF-7 cells.The protein expression levels of SHP-1,nuclear SP1,DNA methyltransferase-1(DNMT1),PU.1 and phosphorylated spleen tyrosine kinase(p-SYK)were detected by Western blotting.The levels of oxidative stress and the polarization of M1 and M2 macrophages in THP-1 cells were detected by RT-qPCR.TUNEL assay was utilized to detect the apoptosis level of tumor cells.Results:Bioinformatics analysis showed that SHP-1(PTPN6)inhibited ROS expression,while SP1 promoted DNMT1 expression.The transplanted tumors in SHP-1 overexpressed nude mice were significantly larger than those in the control group,while PU.1 overexpression resulted in smaller tumors.The expression of nuclear SP1,DNMT1,arginase-1,and CD206 was significantly higher in SHP-1 overexpression group compared with the control group,while PU.1,p-SYK,NOX2,NOX4,IL-1β,and TNF-α levels were significantly decreased.After the treatment of SP1 inhibitor,the expression of nuclear SP1,DNMT1,arginase-1,and CD206 was significantly decreased,while the expression of PU.1,p-SYK,NOX2,NOX4,IL-1β,and TNF-α was significantly increased.When the expression of SP1 inhibitor and SYK inhibitor were applied,the expression of arginase-1 and CD206 was significantly increased,while the expression of NOX2,NOX4,IL-1β,and TNF-α was markedly decreased.SHP-1 overexpression significantly decreased the apoptosis rate of tumor cells.Apoptosis increased notably upon SP1 inhibitor treatment but decreased again when both SP1 and SYK inhibitors were applied.Conclusion:Overexpression of SHP-1 in tumor-associated macrophages promotes the activation of SP1/DNMT1 signaling pathway,which subsequently down-regulates the expression of PU.1 and SYK,and inhibits oxidative stress-induced inflammatory responses,thereby promoting breast cancer progression.