Contributions Of PKD2/3-induced Tumor-derived Factors To The Mast Cell Recruitment And Tumor Angiogenesis In Prostate Cancer Microenvironment

Objectives:It was observed that different types of mast cells were recruited in several tumor environments.Some research showed that the mast cells recruitment and the cytokine secretion correlated with tumor angiogenesis.Our recent studies showed that PKD2/3 are crucial kinase in prostate cancer proliferation,invasion and migration.However,the relationship between PKD2/3,tumor environments and tumor angiogenesis still unclear.This research investigated how PKD2/3 regulated mast cells recruitment promoting tumor development and procession through related signaling pathway.Method:In this experiment,we explored the PKD activity promoted mast cell recruitment and tumor angiogenesis.Mast cell recruitment correlated with tumor angiogenesis in clinical research.Moreover,using knockdown and overexpression PKD2/3,transwell trail and in vivo experiment proved that PKD2/3 promoted mast cells recruitment,the cytokine secretion and tumor angiogenesis.In the end,using western blotting,IP and ChIP provided the mechanism of mast cell recruitment and cytokine secretion in prostate cancer through PKD2/3 activity.Results:(1)The expression of PKD phosphorylation,CD31(marker of microvessel)and c-Kit(mast cells number)were significantly increased in prostate cancers when compared with normal tissue using prostate cancer tissue microarray.It is the positive correlation between PKD phosphorylation,mast cells recruitment and tumor angiogenesis.(2)The P815 and BMMCs mast cells migration inhibited by using PKDs inhibitors kb-NB142-70 or knockdown PKD2/3 in prostate cancer cells.PKD2/3 in prostate cancer cells triggered the infiltration of,and angiogenic factor expression in,MCs which increased the expression of TNF-α,IL-6,IL-8,FGF-2,VEGF and IL-10.It indicates that PKD2/3 are critical mediators of tumor angiogenesis via the recruitment of MCs.(3)Knockdown PKD2/3 mediated chemoattraction of mast cells through SCF,CCL5,and CCL11 mRNA expression and secretion in prostate cancer cells.(4)PKD2/3 interacted with Erk1/2,but not p38.(5)Overexpressing PKD2/3 treated with NF-κB inhibitor BAY11-7082 and Erk1/2 inhibitor PD98059 antagonized the secretion effect of SCF,CCL5,and CCL11.It prompted that PKD2/3 activated NF-κB and Erk1/2 pathway and regulated NF-κB and Erk1/2 transcriptional activation promoting SCF,CCL5 and CCL11 expression.(6)Ablation of PKD2/3 reduced the binding of AP-1 and NF-κB to the promoter of SCF,CCL5 and CCL11,suppressing the transcriptional activation of these chemokines through NF-κB and Erk1/2 signaling using the chromatin immunoprecipitation assay and RT-qPCR analysis.(7)In vivo animal studies showed that tumor volume and proliferation growth were reduced significantly by treatment with a PKD inhibitor in mice bearing RM-1 prostate cancer immune-complete xenograft tumors cells,which correlating to was attributed to the attenuation of mast cell recruitment and tumor angiogenesis in the tumor microenvironment.Conclusion:These results suggest that PKDs may contribute to prostate cancer progression,and that the underlying mechanism involves the regulation of mast-cell recruitment by chemotaxis,thereby leading to tumor angiogenesis.