Aim To observe the effect of BAPTA-AM on extracellular acid-induced autophagy in rat articular chondrocytes and its possible mechanisms.Methods Rat articular chondrocytes were isolated from Sprague-Dawley rats and incubated with different pH medium. The states of autophagy were examined by acridine or-ange (AO ) staining .Moreover,the expressions of LC3 ,Beclin-1 ,ULK1 ,CaMKKβ,AMPK and mTOR were detected using Western blot or quantitative real-time PCR (qRT-PCR ). Intracellular calcium ([Ca2+]i )was analyzed by a Ca2+-imaging method. Results Compared with pH 6.0 group,BAPTA-AM could significantly decrease the activation of autophagyinduced by acid exposure,and the expressions of autophagy markers including LC3 Ⅱ,Beclin1 and ULK1were also decreased,accompanied with reduced acidinduced [Ca2 +]i influx,decreased proteins expressionof CaMKKβand phosphorylatedAMPK,and increasedphosphorylation of mTOR.Conclusion BAPTAAMcan significantly restrain acidinduced autophagy in ratarticular chondrocytes,the mechanism of which may beassociated with decreased Ca2 + influx.

Aim To investigate the effect of 4-Amino- 2-Trifluoromethyl-Phenyl Retinate on human breast cancer cells MDA-MB-231 and the possible mecha-nisms. Method Human breast cancer MDA-MB-231 cells were incubated with different concentrations of ATPR in vitro. MTT assay was performed to measure the proliferation of MDA-MB-231 . Cell growth curves were made by counting cells and morphologic changes were observed by Wright-Giemsa staining. The differ-entiation marker mucin-1 ( MUC-1 ) was measured by enzyme linked immunosorbent assay ( ELISA ) . Cell cycle was examined by Flow cytometry ( FCM ) . The expression of retinoic acid receptors ( RARs) and reti-noid X receptors ( RXRs ) were detected by Western blot and Quantitative real-time PCR (q-RT-PCR),re-spectively. Results Compared with solvent group, ATPR could inhibit the proliferation of MDA-MB-231 cells in a time-and dose dependent manner and induce the maturing and normality of morphology. The express of MUC-1 was significantly decreased, and the progres of cell cycle was blocked in the G0/G1-phase. The ex-pression of RARγ was decreased. Conclusions AT-PR could inhibit proliferation and induce differention of MDA-MB-231cells, it′s associated with RARγ.