ABSTRACT
Objective To detect the effects of siRNA targeting CDX2 gene expression on of BCR-ABL, caspase and Bax expressions, and the mechanisms thereof. Methods According to the earlier experiments, siRNA specifically targeting CDX2 gene (CDX2-siRNA) and the negative control sequence (CDX2-siRNA-NC) were selected, and then were transfected into K562 cells by Roche X-tremeGENE HP DNA Transfection Reagent. The flow cytometry analysis was used to detect the effects of siRNA on cell apoptosis. The expressions of BCR-ABL, caspase-9, Bax mRNA and protein were tested by RT-PCR and Western blot assay. Results MTT and flow cytometry analysis showed that after the silence of CDX2 gene expression, the proliferation of K562 cells was prohibited and the apoptotic rate of K562 cells was distinctly increased compared with that of normal cell group, but the negative control group had no significant change. According to the RT-PCR and Western blot assay, in comparison with the normal cell group and the negative control group, the expression levels of BCR-ABL mRNA and protein were obviously decreased, and the difference was statistic significance. On the other hand, the expressions of caspase-9 and Bax mRNA and protein were significantly higher than those of other two groups (P<0.05). Conclusion CDX2-siRNA can promote apoptosis of K562 cells obviously, and the mechanism is related with the down-regulation of BCR-ABL and the up-regulation of caspase-9 and Bax.
ABSTRACT
The distinctive LT siRNAs were designed according to the LT sequence .During the process of cultivation ,siRNA targeting the LT gene ,non‐specific control siRNA ,negative control siRNA and culture medium were added into siRNA group (siRNA‐LT1 group , siRNA‐LT2 group) ,siRNA‐coa3 group ,siRNA‐NC group and blank control group ,respectively ,and three times in each group (1 nmol each time) .After siRNA added at the first time ,bacteria was collected in 45 min (A) ,90 min (B) and 135 min (C) time points .The expression of mRNA in three time points (A ,B and C) were detected by real‐time fluorescence quantitative PCR .The protein level of LT in siRNA‐LT1 group ,siRNA‐LT2 group and blank control group were detected by Western blot in three time points .Results The results of real‐time fluorescence quantitative PCR showed that inhibition of siRNA‐LT1 on the expression of LT mRNA at the three time points(A ,B and C)were 70 .9% ,70 .1% ,72 .5% respectively ,and inhibition of siRNA‐LT2 on the ex‐pression of LT mRNA at the three time points(A ,B and C)were 70 .1% ,69 .2% and 70 .5% respectively .In the three time points (A ,B and C)the inhibition rate of the expression of LT mRNA in siRNA‐LT1 group and siRNA‐LT2 group were statistically lower than that in the siRNA‐NC group ,siRNA‐coa3 group and blank control group (P<0 .05) .The results of Western blot showed that in siRNA‐LT1 group the inhibitory rate of expression of LT protein in the three time points were 43 .1% ,18 .4% and 5 .0% ,re‐spectively ;in the siRNA‐LT2 group were 38 .2% ,15 .4% and 30 .1% ,respectively .Conclusion The specific siRNA could inhibit the expression of LT gene in vitro .
ABSTRACT
The definition of epigenetics and its cellular basis are introduced firstly in the paper. Then, the research progress on the relationship between cognition and epigenetic changes is re-viewed in detail. In conclusion, epigenetic modifications occur-ring in hippocampus, cortex and other brain areas such as methy-lation , phosphorylation , ubiquitination , poly ( ADP-ribos ) poly-merases and DNA methylation may certainly change animal be-haviors including learning, memory, synaptic plasticity, depres-sion, drug abuse and so on. Long-term memory and long-term potentiation( LTP) , activation of AMPK-ERK signal transduction path-way and activation of key gene regulated by CREB-ABP transcriptional complex as well as transcription and expression of memory and synaptic plasticity related genes ( Zif/268, Creb, Bdnf, reelin ) are required. In contrast, epigenetic abnormal changes such as histone and DNA hypomethylation and increase of HDAC activity are observed in brains of aging and neurodegen-erative diseases. Therefore, the main epigenetic treatments for cognitive impairments are increasing histone and DNA methyla-tion, using HDAC inhibitors and RNA interference ( RNAi) to promote formation of long term memory and long term potentia-tion, block learning and memory decline.