Change of Autophagic Activity of U266 Cells after Bortezomib -Resistance and Its Mechanisms / 中国实验血液学杂志

OBJECTIVE@#To explore the changes of autophagic activity after resistance of U266 cells to bortezomib (Bor) and its mechanisms.@*METHODS@#The proliferation inhibition rate, 50% inhibitory concentration (IC), drug-resistance coefficient, drug-resistance reversed multiple by 3-methyladenine (3-MA) in U266 and U266/Bor cells treated with Bor were detected and calculated by using MTT method, then the proliferation inhibition curve was drawed. The Western blot was used to detect the expression of LC3-I, IC3-II, p-mTOR, Beclin-1, ATG5 and ATG7 proteins.@*RESULTS@#The Bor showed the its proliferation inhibition effect on U266 cells and U266/Bor cells, IC of Bor on U266 and U266/Bor cells on 24 hours were 35.7 nmol/L and 526.5 nmol/L respectively; the drug-resistance coefficient was 14.7; the drug-resistance reversed multiple by 3-MA was 2.7. The expression of LC3-II, Beclin11, ATG5 and ATG7 in U266/Bor cells was higher than that in U266 cells; after the treatment with Bor for 24 h, the expression levels of LC3-II, Beclin-1, ATG5 and ATG7 in U266 cells all decreased, as compared with levels before treatment; while the expression levels of LC3-II, Beclin-1, ATG5 and ATG7 in U266/Bor cells were higher than those before treatment. There were no significant difference of p-mTOR expression among U266, U266+Bor, U266/Bor, U266/Bor+Bor cells.@*CONCLUSION@#The increase of autophagy closely relates with resistance of U266 cells to bortezomib, moreover with up-regulation of Beclin-1, ATG5 and ATG7 expression.

Reversal Effect of Pioglitazone on Multidrug Resistance in K562/ADR Cells and Its Mechanism / 中国实验血液学杂志

OBJECTIVE@#To explore the reversal effect of pioglitazone (PIO) on multidrug resistance in K562/ADR cells and its mechanism.@*METHODS@#The proliferation inhibition rate, half inhibition concentration (IC) and drug-resistance reversal multipe were detected and the curve of proliferation inhibition rate was drawn by MTT assay, the transcription of PPARγ, CYP2C8 and CYP2J2 genes was detected by RT-PCR; the expression of PPARγ, CYP2C8 and CYP2J2 proteins was detected by Western blot.@*RESULTS@#The IC of PIO on K562 and K562/ADR cells for 60 h was 326.7 μmol/L and 349.1 μmol/L respectively. The reversal multiple of 30 μmol/L PIO on ADR-resistance of K562/ADR cells was 6.4. After treatment of K562/ADR cells with PIO, the transcription of CYP2C8 and CYP2J2 and the protein expression of CYP2C8 and CYP2J2 significantly decreased, the transcription of PPARγ gene and the expression of PPARγ protein were not changed.@*CONCLUSIONS@#Pioglitazone can reverse the adriamycin-resistance in K562/ADR cells that is closely related to the decrease of protein expression of CYP2C8 and CYP2J2. Pioglitazone is an effective multidrug resistance reversal agent for tumors.