Objectives:While programmed cell death 1(PD-1)inhibitors have improved cancer treatment,the function and mechanisms of programmed cell death ligand 1(PD-L1),particularly when expressed by cancer cells,remain unclear.T...Objectives:While programmed cell death 1(PD-1)inhibitors have improved cancer treatment,the function and mechanisms of programmed cell death ligand 1(PD-L1),particularly when expressed by cancer cells,remain unclear.This study aims to explore the role of PD-L1 within breast cancer cells and identify key targets for future immunotherapy.Methods:RNA-seq was performed on breast cancer cells with silenced PD-L1 to screen for differentially expressed genes,followed by bioinformatics analysis.Clinical specimens from breast cancer patients undergoing primary surgery without preoperative treatment were collected,along with in vitro analysis to validate the potential mechanism.Results:RNA-seq data revealed a significant positive correlation between Ecto-5′-nucleotidase(NT5E)expression and PD-L1.Bioinformatics analysis corroborated this positive correlation.Immunohistochemistry staining demonstrated higher NT5E expression associated with increased lymph node metastasis.High expression of the NT5E gene was associated with poor overall survival(OS)in breast cancer patients,as determined by KM plotter analysis.Following PD-L1 gene silencing by siRNA in breast cancer cells,NT5E mRNA and protein expression significantly decreased.Conversely,no significant changes were observed in PD-L1 expression after NT5E gene silencing.In vitro experiments confirmed that cancer cell proliferation and metastasis abilities were significantly reduced by either PD-L1 or NT5E gene down-regulation.Western blotting demonstrated that PD-L1 expressed by cancer cells regulates NT5E expression through the MAPK/ERK signaling pathway.Conclusion:This study proposes a potential mechanism wherein tumor-expressing PD-L1 regulates NT5E through the MAPK/ERK pathway.Downregulation of PD-L1 or NT5E can significantly inhibit the proliferation and metastatic ability of cancer cells,potentially providing practical therapeutic targets and prognostic markers for combined PD-L1 immunotherapy in breast cancer.展开更多
BACKGROUND Chemotherapy for triple-negative breast cancer(TNBC)is often limited in efficacy due to drug resistance.The NOTCH1 pathway significantly contributes to the advancement of tumors,but its mechanism of action ...BACKGROUND Chemotherapy for triple-negative breast cancer(TNBC)is often limited in efficacy due to drug resistance.The NOTCH1 pathway significantly contributes to the advancement of tumors,but its mechanism of action in sensitizing TNBC to chemotherapy and its association with the downstream molecule,NT5E,is unclear.AIM To explore the molecular mechanisms by which NOTCH1 regulates cisplatin sensitivity in TNBC cells,and to validate its synergistic effect with NT5E.METHODS Expression of NOTCH1 in MDA-MB-231 cells was silenced using RNA interference,and the changes in cell proliferation,migration and cisplatin sensitivity were measured in combination with cell function experiments.The regulatory relationship between NOTCH1 and NT5E was analyzed using qPCR and Western blotting,and the silencing effect of NOTCH1 was verified using NT5E overexpression experiments.RESULTS Knockdown of NOTCH1 hindered the growth and motility of TNBC cells and lowered cisplatin’s half-maximal inhibitory concentration.Expression of NOTCH1 and NT5E was positively correlated,and NOTCH1 silencing led to a decrease in the expression of NT5E.Elevated NT5E expression attenuated the suppressive effects of NOTCH1 knockdown on both cell proliferation and cisplatin response.CONCLUSION NOTCH1 enhances TNBC cisplatin chemosensitivity by regulating NT5E expression.This study provides a new target and experimental basis for the development of combination therapy strategies for TNBC.展开更多
基金Provincial Natural Science Foundation J230016Provincial Natural Science Foundation H2023206441Hebei Province Major Science and Technology Support Program Project S&T Program of Hebei 242W7701Z.
文摘Objectives:While programmed cell death 1(PD-1)inhibitors have improved cancer treatment,the function and mechanisms of programmed cell death ligand 1(PD-L1),particularly when expressed by cancer cells,remain unclear.This study aims to explore the role of PD-L1 within breast cancer cells and identify key targets for future immunotherapy.Methods:RNA-seq was performed on breast cancer cells with silenced PD-L1 to screen for differentially expressed genes,followed by bioinformatics analysis.Clinical specimens from breast cancer patients undergoing primary surgery without preoperative treatment were collected,along with in vitro analysis to validate the potential mechanism.Results:RNA-seq data revealed a significant positive correlation between Ecto-5′-nucleotidase(NT5E)expression and PD-L1.Bioinformatics analysis corroborated this positive correlation.Immunohistochemistry staining demonstrated higher NT5E expression associated with increased lymph node metastasis.High expression of the NT5E gene was associated with poor overall survival(OS)in breast cancer patients,as determined by KM plotter analysis.Following PD-L1 gene silencing by siRNA in breast cancer cells,NT5E mRNA and protein expression significantly decreased.Conversely,no significant changes were observed in PD-L1 expression after NT5E gene silencing.In vitro experiments confirmed that cancer cell proliferation and metastasis abilities were significantly reduced by either PD-L1 or NT5E gene down-regulation.Western blotting demonstrated that PD-L1 expressed by cancer cells regulates NT5E expression through the MAPK/ERK signaling pathway.Conclusion:This study proposes a potential mechanism wherein tumor-expressing PD-L1 regulates NT5E through the MAPK/ERK pathway.Downregulation of PD-L1 or NT5E can significantly inhibit the proliferation and metastatic ability of cancer cells,potentially providing practical therapeutic targets and prognostic markers for combined PD-L1 immunotherapy in breast cancer.
基金Supported by National Natural Science Foundation of China,No.82273457the Natural Science Foundation of Guangdong Province,No.2021A1515012180 and No.2023A1515012762+1 种基金Science and Technology Special Project of Guangdong Province,No.210715216902829 and No.200628175260810‘Dengfeng Project’for the Construction of High-Level Hospitals in Guangdong Province—First Affiliated Hospital of Shantou University College Supporting Funding,No.202003-10.
文摘BACKGROUND Chemotherapy for triple-negative breast cancer(TNBC)is often limited in efficacy due to drug resistance.The NOTCH1 pathway significantly contributes to the advancement of tumors,but its mechanism of action in sensitizing TNBC to chemotherapy and its association with the downstream molecule,NT5E,is unclear.AIM To explore the molecular mechanisms by which NOTCH1 regulates cisplatin sensitivity in TNBC cells,and to validate its synergistic effect with NT5E.METHODS Expression of NOTCH1 in MDA-MB-231 cells was silenced using RNA interference,and the changes in cell proliferation,migration and cisplatin sensitivity were measured in combination with cell function experiments.The regulatory relationship between NOTCH1 and NT5E was analyzed using qPCR and Western blotting,and the silencing effect of NOTCH1 was verified using NT5E overexpression experiments.RESULTS Knockdown of NOTCH1 hindered the growth and motility of TNBC cells and lowered cisplatin’s half-maximal inhibitory concentration.Expression of NOTCH1 and NT5E was positively correlated,and NOTCH1 silencing led to a decrease in the expression of NT5E.Elevated NT5E expression attenuated the suppressive effects of NOTCH1 knockdown on both cell proliferation and cisplatin response.CONCLUSION NOTCH1 enhances TNBC cisplatin chemosensitivity by regulating NT5E expression.This study provides a new target and experimental basis for the development of combination therapy strategies for TNBC.
