Background: Lithium and valproic acid (VPA) exhibit a robust neuroprotective and anti-tumor effects in neural cells and tumor cells. Results: Lithium significantly down-regulates HDAC1 at the translational level by targeting HDAC1 mRNA. Conclusion:The decrease in HDAC1 is essential for the lithium-mediated, autophagic degradation of mutant huntingtin. Significance: This report is the first demonstration that HDAC1 decreases in response to lithium treatment.

Phenylalanine ammonia-lyase (PAL) is the key enzyme of the phenylpropanoid pathway, playing an important role in plant development and defence. We cloned a partial cDNA of PAL gene, DcPAL1, from Dracaena cambodiana seedlings using RT-PCR with degenerate primers that were designed based on a multiple sequence alignment of known PAL genes from other plant species. DcPAL1 shows highly homologous to other known PAL genes registered in GenBank, being closest to that of Musa acuminata. DcPAL1 has a relatively high GC content and most of the GC is in the third codon position. It has 768 bp in size with a maximum open reading frame (ORF) of 765 bp, encoding a 255 amino acid-polypeptide. The deduced PAL protein is a stable protein, having classical PAL domains and consisting of three major hydrophobic domains. Analysis of effective number of codons (ENC) shows that DcPAL1 codons are used at equal frequency. Relatively higher usage frequency appears randomly in codons ended with any of the four bases; six codons have no usage bias. There are 45 codons showing distinct usage preference between DcPAL1 and E. coli, 20 between DcPAL1 and yeast. Therefore, the yeast system may be more suitable for the expression of DcPAL1. Upon the elicitation of Fusarium proliferatum, a potent elicitor of dragon's blood, the PAL enzyme activity in the leaves and stems of D. cambodiana and other two Dracaena spp. significantly increased, accompanying with the formation of dragon's blood, indicating the involvement of PAL in the biosynthesis of dragon's blood, a precious traditional medicine.

AIM:To investigate the effects of curcumin on the expression of peroxisome proliferator-activated receptorδ (PPARδ) and related genes in HT-29 cells. METHODS:HT-29 cells were treated with curcumin (0-80 μmol/L) for 24 h. The effects of curcumin on the morphology of HT-29 cells were studied by Hoechst 33342 staining. The activity of caspase-3 was determined using DEVD-p NA as substrate. The levels of peroxisome PPARδ, 14-3-3ε and vascular endothelial growth factor (VEGF) in HT-29 cells were determined by Western blotting analysis and their mRNA expression was determined by real-time quantitative RT-PCR. RESULTS:Treatment with 10-80 μmol/L curcumin induced typical features of apoptosis and activated the caspase-3 in HT-29 cells. The expression of PPARδ, 14-3-3ε and VEGF was reduced and the activity of β-catenin/Tcf-4 signaling was inhibited by curcumin treatment. CONCLUSION:Curcumin can induce apoptosis of HT-29 cells and down-regulate the expression of PPARδ, 14-3-3ε and VEGF in HT-29.

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