High glucose induces expression of osteopontin through activation of PI3 K/AKT/mTORC1 pathway in human renal tubular epithelial cells / 中国药理学通报

Aim Toexplorethemechanismofupregu-lation of osteopontin ( OPN ) expression induced by high glucose in human renal tubular epithelial cells (HK-2cells).Methods Afterstimulationwithhigh-glucose (25 mmol·L-1 ) culture medium, HK-2 cells were then treated with the specific inhibitors or siRNA to inhibit the activity of PI3K and/or mTOR. Subse-quently, Real-time PCR was used to investigate the mRNA level of OPN, and Western blot was performed to detect the protein expression of OPN, p-AKT, p-S6,RaptorandRictor.Results Theexpressionlevel of OPN was increased in a time-dependent manner in HK-2 cells followed by high-glucose stimulation. The mRNA level of OPN peaked at 48 h; while the protein expression of OPN reached the highest level at 72h. Meanwhile, high glucose activated the PI3K/AKT/mTOR signaling pathway. Moreover, inhibition of the PI3 K/AKT/mTOR pathway by LY294002 and/or rapa-mycin led to significant down-regulation of OPN. Addi-tionally, the treatment with Raptor siRNA, but not Rictor siRNA resulted in reduction of OPN expression. Conclusion Highglucoseincreasestheexpressionof OPN through the activation of PI3 K/AKT/mTORC1 signaling pathway in HK-2 cells.

Effect of rapamycin on the potential metastasis of squamous cell carcinoma in vitro / 中国药理学通报

Aim To investigate the effect of rapamycin on proliferation, migration, and invasion of squamous cell carcinoma A431 cells in vitro. Methods Human squamous cell carcinoma A431 cells were cultured in vitro. MTT assay was used to investigate proliferation of A431 cells treated by rapamycin at different concentra-tions of (5,10,20 nmol·L-1). Wound healing and transwell assay were performed to detect migration and invasion of A431 cells treated by rapamycin, respec-tively. Reverse transcription PCR ( RT-PCR ) and Western blot were used to determine the expression of the osteopontin ( OPN ) in A431 cells at mRNA level and protein level, respectively. Results Rapamycin significantly increased the inhibitory rates of prolifera-tion and inhibited the migration and invasion of A431 cells in vitro. Furthermore, rapamycin treatment re-duced the expression of OPN in A431 cells. Conclu-sions Rapamycin can inhibit the migration and inva-sion of A431 . The intrinsic mechanism of rapamycin might be related to the down-regulation of the OPN ex-pression.