Backgrounds:Breast cancer metastasis remains the leading cause of mortality and frequently targets the bone.Breast cancer cells release soluble factors and extracellular vesicles that disrupt bone marrow(BM)/bone home...Backgrounds:Breast cancer metastasis remains the leading cause of mortality and frequently targets the bone.Breast cancer cells release soluble factors and extracellular vesicles that disrupt bone marrow(BM)/bone homeostasis,promoting osteoclastogenesis and the accumulation of senescent cells.In line with updated cancer hallmarks,senescent mesenchymal stem/stromal cells(MSCs),osteoblasts,and osteocytes contribute to remodeling of the BM microenvironment,thereby favoring pre-metastatic niche(PMN)formation and subsequent bone metastasis.We previously demonstrated that untreated stage III-B breast cancer patients(BCPs)exhibit increased oxidative stress and elevated reactive oxygen species(ROS)levels,accompanied by senescent and functionally impaired BM-MSCs—key regulators of BM/bone homeostasis.In the present study,we sought to identify the molecular targets affected by oxidative stress that drive MSC senescence in these patients.Methods:BM-MSCs were isolated from untreated stage III-B BCPs and healthy volunteers(HVs).Oxidative stress responses were evaluated by quantitative real-time PCR(qRT-PCR)analysis of stress-and antioxidant-related genes.Oxidative damage to DNA,proteins,and lipids was assessed using alkaline comet assay,chromosomal aberration(CAs)analysis,micronuclei(MN)and nuclear blebs(NBs)quantification,protein carbonyl content,and detection of 4-hydroxynonenal(4-HNE)adducts.The MSC secretome was analyzed by label-free quantitative proteomics followed by Gene Ontology enrichment analysis.Results:Our results show that elevated oxidative stress in BCPs induces the overexpression of oxidative stress-related and antioxidant response genes in BM-MSCs;however,this response is insufficient to prevent extensive ROS-induced damage to deoxyribonucleic acid(DNA),proteins,and lipids.In addition,proteomic analysis of the BM-MSC secretome revealed a distinct protein expression profile in BCPs compared with HVs.Conclusions:Together,these findings highlight oxidative stress-induced MSC damage as a key mechanism contributing to PMN formation and suggest potential therapeutic targets to mitigate bone metastasis in advanced breast cancer.展开更多
基金supported by the FONCYT,PICT 2016-#1093,Argentina.CONICET,PIP2014-#300,Argentina.Florencio Fiorini Foundation(#2021-2022),Argentina.
文摘Backgrounds:Breast cancer metastasis remains the leading cause of mortality and frequently targets the bone.Breast cancer cells release soluble factors and extracellular vesicles that disrupt bone marrow(BM)/bone homeostasis,promoting osteoclastogenesis and the accumulation of senescent cells.In line with updated cancer hallmarks,senescent mesenchymal stem/stromal cells(MSCs),osteoblasts,and osteocytes contribute to remodeling of the BM microenvironment,thereby favoring pre-metastatic niche(PMN)formation and subsequent bone metastasis.We previously demonstrated that untreated stage III-B breast cancer patients(BCPs)exhibit increased oxidative stress and elevated reactive oxygen species(ROS)levels,accompanied by senescent and functionally impaired BM-MSCs—key regulators of BM/bone homeostasis.In the present study,we sought to identify the molecular targets affected by oxidative stress that drive MSC senescence in these patients.Methods:BM-MSCs were isolated from untreated stage III-B BCPs and healthy volunteers(HVs).Oxidative stress responses were evaluated by quantitative real-time PCR(qRT-PCR)analysis of stress-and antioxidant-related genes.Oxidative damage to DNA,proteins,and lipids was assessed using alkaline comet assay,chromosomal aberration(CAs)analysis,micronuclei(MN)and nuclear blebs(NBs)quantification,protein carbonyl content,and detection of 4-hydroxynonenal(4-HNE)adducts.The MSC secretome was analyzed by label-free quantitative proteomics followed by Gene Ontology enrichment analysis.Results:Our results show that elevated oxidative stress in BCPs induces the overexpression of oxidative stress-related and antioxidant response genes in BM-MSCs;however,this response is insufficient to prevent extensive ROS-induced damage to deoxyribonucleic acid(DNA),proteins,and lipids.In addition,proteomic analysis of the BM-MSC secretome revealed a distinct protein expression profile in BCPs compared with HVs.Conclusions:Together,these findings highlight oxidative stress-induced MSC damage as a key mechanism contributing to PMN formation and suggest potential therapeutic targets to mitigate bone metastasis in advanced breast cancer.
