Metformin inhibits proliferation and promotes apoptosis of HER-2 positive breast cancer cells possibly through the Hippo-YAP pathway / 南方医科大学学报

OBJECTIVE@#To investigate the effect of metformin on the proliferation and apoptosis of HER-2-positive breast cancer cell line SKBR3 and explore the possible mechanism of its action.@*METHODS@#SKBR3 cells were treated with different concentrations (20-120 μmol/L) of metformin, and the changes in cell proliferation and colony formation ability were assessed using CCK-8 assay and crystal violet staining, respectively. Flow cytometry was performed to analyze cell apoptosis and cell cycle changes. Real-time fluorescent quantitative PCR (qRT-PCR) was used to detect mRNA expressions of YAP, TAZ, EGFR, CTGF, CYR61, E-cadherin, N-cadherin, vimentin and fibronectin in the treated cells, and the protein expressions of YAP and TAZ were detected using Western blotting; immunofluorescence assay was used to observe YAP/TAZ nuclear translocation in the cells.@*RESULTS@#Metformin treatment significantly inhibited the proliferation of SKBR3 cells (P < 0.05) in a concentration- and time-dependent manner. The results of flow cytometry showed that metformin significantly promoted apoptosis and caused cell cycle arrest at G1 phase in SKBR3 cells. Metformin treatment significantly down-regulated the mRNA expressions of YAP, TAZ, EGFR, CTGF and CYR61, N-cadherin, vimentin and fibronectin (P < 0.05) and up-regulated the expression of E-cadherin (P < 0.05); Western blotting results showed that YAP and TAZ protein expressions were significantly down-regulated in the cells after metformin treatment (P < 0.05). Immunofluorescence assay revealed that metformin treatment caused the concentration of YAP and TAZ in the cytoplasm, and significantly reduced their amount in the cell nucleus.@*CONCLUSION@#Metformin can inhibit proliferation and promote apoptosis and epithelal-mesenchymal transition of HER-2 positive breast cancer cells possibly by that inhibing YAP and TAZ expression and their nuclear localization.

Stimulation of Yes-associated protein activity attenuates lung injury repair induced by LPS in mice / 中国临床药理学与治疗学

AIM: To observe the effect and possible mechanism of stimulation of Yes-associated protein (YAP) activity on acute lung injury and repair induced by LPS in mice. METHODS: Ninety adult male ICR mice were divided into two groups: acute lung injury model group induced by LPS (7.5 mg/kg, i.p.) and LPS+XMU treatment (1 mg•kg-1•d-1) group. At 0 h, 24 h, 48 h and 72 h after LPS injection, the contents of TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF) were detected by ELISA method. The activity of myeloperoxidase (MPO) and the content of protein in BALF were evaluated by chemical technique. The protein level of nuclear YAP, cytosol phosphorylated YAP (P-YAP), connective tissue growth factor (CTGF) and proliferating cell nuclear antigen (PCNA) in lung were analyzed by Western blot. RESULTS:The protein level of nuclear YAP at 24 h, 48 h and 72 h in lung of LPS+XMU group were up-regulated than those of LPS group by 39.2%, 148.1% and 42.9%, and the protein level of CTGF in lung were up-regulated than those of LPS group by 186.6%, 10.1% and 146.1% (P<0.05), respectively, while the protein level of cytosol P-YAP was down-regulated. The content of IL-6 and TNF-α at 24 h in BALF of LPS+XMU group were lower than those of LPS group by 28.4% and 23.7%, and the activity of MPO and the content of TNF-α at 48 h in BALF were lower by 13.5% and 39.5%, and the content of IL-6 and TNF-α at 72 h in BALF were lower by 42.8% and 16.7% (P<0.05), respectively. The protein level of PCNA at 48 h and 72 h in lung of LPS+XMU group were up-regulated than those of LPS group by 44.2% and 14.9% (P<0.05), respectively, while there was no significant difference at 24 h. The content of protein at 24 h, 48 h and 72 h in BALF of LPS+XMU group were lower than those of LPS group by 32.4%, 46.0% and 26.3% (P<0.05), respectively. The pathological changes showed a significantly attenuated tissue injury and accelerated recovery from lung injury in LPS+XMU group compared with mice injected with LPS alone at each times point. CONCLUSION: Stimulation of YAP activity attenuates lung injury and promotes lung recovery by alleviating lung inflammation and injury at injury phase, but by promoting inflammation resolution and stimulating cell proliferation at repair phase.

Citron Rho-interacting serine/threonine kinase knockdown suppresses prostate cancer cell proliferation and metastasis by blocking Hippo-YAP pathway / 南方医科大学学报

OBJECTIVE@#Citron Rho-interacting serine/threonine kinase (CIT) was identified recently as an oncogene involved in the progression of various malignant tumors, but its role in prostate cancer (PCa) remains unclear. In this study, we aimed to investigate the biological functions of CIT in PCa.@*METHODS@#We analyzed the expression of CIT in PCa tissues and its clinical correlations based on the Cancer Genome Atlas (TCGA) and Memorial Sloan-Kettering Cancer Center (MSKCC) dataset. We then examined the effects of RNA interference-mediated CIT silencing on the proliferation, migration and invasion of PC-3 cells using cell counting kit-8, wound healing assay and Transwell assay. We also investigated the effect of CIT silencing on epithelial-mesenchymal transition (EMT) and Hippo-Yap signaling pathway in the cells using Western blotting.@*RESULTS@#CIT expression was significantly elevated in PCa tissues from TCGA cohort ( < 0.05). MSKCC dataset analysis showed that an elevated expression of CIT was significantly correlated with N stage (=0.001), distant metastasis ( < 0.001), Gleason score (=0.010) and PSA (=0.004). In cultured PC-3 cells, knockdown of CIT significantly inhibited cell proliferation, migration and invasion, reversed the EMT phenotype and decreased the expression and activity of YAP.@*CONCLUSIONS@#CIT might function as an oncogene in PCa by modulating the Hippo-YAP signaling pathway and serve as a candidate therapeutic target for PCa.

Pseudolaric Acid B Inhibits Proliferation, Invasion and Epithelial-to-Mesenchymal Transition in Human Pancreatic Cancer Cell

PURPOSE: This study was aimed to investigate the effect of pseudolaric acid B (PAB) on proliferation, invasion and epithelial-to-mesenchymal transition (EMT) in pancreatic cancer cells and to explore the possible mechanism. MATERIALS AND METHODS: The pancreatic cancer cell line SW1990 was cultured and treated with PAB dose- and time-dependent manners. Cell proliferation and invasion ability were measured by MTT assay and Matrigel/Transwell test, respectively. Semi-quantitative real-time polymerase chain reaction and Western blotting were conducted to detect the expression of EMT markers and the key molecules. Finally, nude mice subcutaneous transplantation tumor model was used to confirm the therapy efficacy of PAB. RESULTS: PAB could inhibit SW1990 cell proliferation and invasion in time- and dose-dependent manners. Vimentin, fibronectin, N-cadherin, Snail, Slug, YAP, TEAD1, and Survivin were down-regulated (p < 0.01), while E-cadherin, caspase-9, MST1, and pYAP were up-regulated (p < 0.05). Combined PAB and gemcitabine treatment markedly restricted the tumor growth compared with gencitabin or PAB alone groups. CONCLUSION: PAB could inhibit the proliferation and invasion ability of pancreatic cancer cells through activating Hippo-YAP pathway and inhibiting the process of EMT.