Objective To explore the biological mechanisms of isorhamnetin(ISO)inhibition of breast cancer(BC)progression and effects on paclitaxel sensitivity by in vivo and in vitro experiments.Methods The effects of ISO on MDA-MB-231 cell viability,migration,invasion and apoptosis were explored by CCK-8,scratch,Transwell invasion and apoptosis assays.ISO biological functions were analyzed and core target genes were identified by genome-wide microarrays,functional enrichment and protein-protein interactions(PPI).CYP1B1 expression characterization and prognosis in BC were assessed by quantitative Real-time polymerase chain reaction(qRT-PCR),Western blotting(WB),and Kaplan-Meier plotter database.The effects of CYP1B1 overexpression on MDA-MB-231 cell viability,migration,invasion and apoptosis were explored by CCK-8,scratch,Transwell invasion and apoptosis assays.The effects of ISO and CYP1B1 on BC tumor growth were analyzed by establishing a subcutaneous graft tumor animal model and verified by histological analysis with immunohistochemistry(IHC)and hematoxylin and eosin(HE)staining.The effects of ISO and CYP1B1 on NF-κB signaling were analyzed by qRT-PCR and WB.The effect of ISO combined with paclitaxel on BC progression was analyzed by in vitro and in vivo experiments.Results The results of CCK-8 assay showed that ISO inhibited the viability of MDA-MB-231 cells with an IC50 value of 11.93 μmol/L;the scratch,Transwell invasion and apoptosis assays confirmed that ISO inhibited the migration and invasion of MDA-MB-231 cells and promoted apoptosis(P＜0.05).Volcano plot showed a total of 80 differentially expressed genes(DEGs),of which ISO promoted the expression of 27 genes and inhibited the expression of 53 genes.Gene set enrichment analyses showed that DEGs were mainly enriched in the signaling of organic hydroxyl compound metabolic process,inflammatory response,sterol metabolic process,and nuclear factor-κB(NF-κB).qRT-PCR,WB,and Kaplan-Meier plotter results showed that CYP1B1 mRNA and protein expression was increased in BC and mediated worse prognosis(P＜0.05).CCK-8,scratch,Transwell invasion and apoptosis assays showed that CYP1B1 overexpression enhanced MDA-MB-231 cell viability,migration and invasion,and inhibited apoptosis,which was reversed by the addition of ISO(P＜0.05).The results of in vivo experiments showed that ISO downregulated CYP1B1 expression and attenuated NF-κB signaling(P＜0.05).The results of in vitro and in vivo experiments showed that ISO combined with paclitaxel significantly inhibited BC cell viability and tumor growth(P＜0.05).Conclusion ISO inhibits BC malignant biological behavior by modulating the CYP1B1/NF-κB signaling axis,and ISO enhances paclitaxel sensitivity.

Objective To explore the biological mechanisms of isorhamnetin(ISO)inhibition of breast cancer(BC)progression and effects on paclitaxel sensitivity by in vivo and in vitro experiments.Methods The effects of ISO on MDA-MB-231 cell viability,migration,invasion and apoptosis were explored by CCK-8,scratch,Transwell invasion and apoptosis assays.ISO biological functions were analyzed and core target genes were identified by genome-wide microarrays,functional enrichment and protein-protein interactions(PPI).CYP1B1 expression characterization and prognosis in BC were assessed by quantitative Real-time polymerase chain reaction(qRT-PCR),Western blotting(WB),and Kaplan-Meier plotter database.The effects of CYP1B1 overexpression on MDA-MB-231 cell viability,migration,invasion and apoptosis were explored by CCK-8,scratch,Transwell invasion and apoptosis assays.The effects of ISO and CYP1B1 on BC tumor growth were analyzed by establishing a subcutaneous graft tumor animal model and verified by histological analysis with immunohistochemistry(IHC)and hematoxylin and eosin(HE)staining.The effects of ISO and CYP1B1 on NF-κB signaling were analyzed by qRT-PCR and WB.The effect of ISO combined with paclitaxel on BC progression was analyzed by in vitro and in vivo experiments.Results The results of CCK-8 assay showed that ISO inhibited the viability of MDA-MB-231 cells with an IC50 value of 11.93 μmol/L;the scratch,Transwell invasion and apoptosis assays confirmed that ISO inhibited the migration and invasion of MDA-MB-231 cells and promoted apoptosis(P＜0.05).Volcano plot showed a total of 80 differentially expressed genes(DEGs),of which ISO promoted the expression of 27 genes and inhibited the expression of 53 genes.Gene set enrichment analyses showed that DEGs were mainly enriched in the signaling of organic hydroxyl compound metabolic process,inflammatory response,sterol metabolic process,and nuclear factor-κB(NF-κB).qRT-PCR,WB,and Kaplan-Meier plotter results showed that CYP1B1 mRNA and protein expression was increased in BC and mediated worse prognosis(P＜0.05).CCK-8,scratch,Transwell invasion and apoptosis assays showed that CYP1B1 overexpression enhanced MDA-MB-231 cell viability,migration and invasion,and inhibited apoptosis,which was reversed by the addition of ISO(P＜0.05).The results of in vivo experiments showed that ISO downregulated CYP1B1 expression and attenuated NF-κB signaling(P＜0.05).The results of in vitro and in vivo experiments showed that ISO combined with paclitaxel significantly inhibited BC cell viability and tumor growth(P＜0.05).Conclusion ISO inhibits BC malignant biological behavior by modulating the CYP1B1/NF-κB signaling axis,and ISO enhances paclitaxel sensitivity.