Reciprocal Network Between Cancer Stem-Like Cells And Macrophages Facilitates The Progression Of Prostate Cancer

ObjectiveTumor heterogeneity is an important reason to promote tumor evolution,disease progression,and lead to treatment failure and poor prognosis in patients.Cancer stem cell-like cells,a subset of the genetic makeup of tumor cell populations,are an important source of tumor heterogeneity.In different tumors,tumor stem cell-like cells have self-renewal ability,chemotherapeutic drug resistance,development of tumor cells,expansion and metastasis potential.Therefore,revealing the inherent molecular mechanism of tumor stem cell-like cells,help to find new therapies for advanced tumors,and provide a theoretical basis for clinical practice.Prostate cancer is one of the leading causes of men's death worldwide and which is highly heterogeneous.Androgen deprivation therapy,as the first-line therapy widely used at present,although it has a short-term relieving effect on advanced or recurrent prostate cancer,eventually leads to a poor prognosis due to irreversible drug resistance.Increasing evidence have shown that androgen deprivation therapy reprogrammed prostate cancer cells during the process of drug resistance,which resulting in the development of cancer stem cell-like cells as a subset of prostate cancer cells.In addition,in the complex tumor microenvironment,various components play a role of mutual promotion with prostate cancer cells.Therefore,exploring the molecular mechanism underlying the interaction between prostate cancer stem cell-like cells and tumor microenvironment cells and jointly block associated pathway elements,will help to improve the effectiveness of androgen deprivation for prostate cancer.Methods and ResultsFirst part: OV6 as an indicator of tumor heterogeneity and prognosis in patients with prostate cancer.In order to evaluate the expression of OV6 in prostate cancer tissue,and its role for indicating the prognosis of patients,we use the immunochemical stain to compare the expression of OV6 in normal prostate tissue,localized prostate cancer,locally advanced prostate cancer,castration resistant prostate cancer,neuroendocrine prostate cancer,different Gleason score area from the same prostate cancer tissue,advanced prostate cancer tissue before and after androgen deprivation treatment,orthotopic prostate cancer xenograft before and after androgen deprivation treatment,and metastastic prostate cancer tissue from xenograft model,The results showed that OV6 was positively correlated withthe degree of malignancy of prostate cancer,and was highly expressed in the region of high Gleason score in the same prostate cancer tissue.Relatively high expression was detected in androgen deprivation treated and metastastic prostate cancer tissue,indicating that OV6 as a useful indicator for tumor heterogeneity and prognosis of patients with prostate cancer.Second part: OV6-positive prostate cancer cells maintain tumor stem cell-like cell characteristics by initiating autophagy.To understand whether OV6-positive prostate cancer cells possess cancer stem cell features and exert the molecular mechanisms of maintaining stem cell properties.We detected the stemness related gene expression of OV6 positive prostate cancer cells by quantitative PCR.The self-renewal ability of OV6 positive prostate cancer cells was detected by assessing spheroid formation in vitro and tumorigenesis in vivo under gradient dilution cell number.We used proliferation and apoptosis assay to evaluate the drug resistance of chemotherapeutic and androgen-deprivation drugs of OV6 positive prostate cancer cells.Through the RNA transcriptome sequencing and a series of molecular biological experiments such as Co-IP,Duolink,ChIP and so on,we explore the molecular mechanism of OV6 positive prostate cancer cells to maintain stem cell characteristics and found that OV6 positive prostate cancer cells can be activated by activating the autophagy ATG7,which maintain the stability of cytoplasmic ?-catenin,and promote the latter into the nuclear to activate the transcription of OCT4,thereby maintaining the characteristics of stem cells.Third part: the interaction between OV6-positive prostate cancer stem-like cells and monocytes promoting androgen deprivation treatment resistance.In the previous studies,we found that inhibition of the internal pathway of OV6-positive prostate cancer cells alone did not significantly improve the therapeutic efficacy of androgen deprivation drug enzulatamide in the orthotopic prostate cancer xenograft model,suggesting that tumor microenvironmental cells may participate in drug resistance formation process.We co-cultured OV6-positive prostate cancer cells with monocytes,and the expression of cytokines in the cell supernatant was detected by antibody microarray and ELISA.IL6 was found to be a key molecule in the interaction between OV6-positive prostate cancer cells and monocytes.This reciprocal interaction,on the one hand,enhances the self-renewal capacity of OV6 positive prostate cancer cells,on the other hand,recruits and promotes the differentiation of monocytes intotumor-associated macrophages.The combined inhibition of ATG7 and IL6 R can effectively increase the effectiveness of prostate cancer cells for the treatment of enzalutamide in the orthotopic prostate cancer xenograft model.ConclusionIn this study,we found that OV6 positive prostate cancer cells have stem cell properties and the ability to recruit and promote the differentiation of monocytes into tumor-associated macrophages.Joint targeting of OV6 positive stem-like prostate cancer cells and their interaction with TAMs ameliorates ADT resistance in an orthotopic prostate cancer model.In conclusion,our study indicates that targeting OV6 positive stem-like prostate cancer cells and their niche may prove to be a more powerful strategy than targeting the OV6 positive stem-like prostate cancer cells alone,which provides a rational approach to ameliorating ADT resistance in prostate cancer...