Peanut testa extracts enhance anticancer effect of cisplatin against human cholangiocarcinoma cells via modulation of histone deacetylase inhibitory activity

Objective: To investigate the effect of combination treatments of cisplatin and KK4 and ICG15042 peanut testa extracts against cholangiocarcinoma cells in vitro.Methods: The growth inhibition, cell cycle arrest and apoptosis of cholangiocarcinoma cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry analysis, respectively. The levels of proteins involved in apoptosis were assessed using Western blotting assays. The caspase activity was assessed using a colorimetric caspase activity assay. Results: Cisplatin and peanut (KK4 and ICG15042) testa extracts inhibited the growth of cholangiocarcinoma cell lines (KKU-M214 and KKU-100 cells) in a dose- and time-dependent manner. The combination treatments reduced cell viability and induced apoptosis of cholangiocarcinoma cells more efficiently than single-drug treatments. Cancer cell death synergistically mediated by cisplatin and peanut testa extracts was observed in KKU-M214 cells (combination index < 1.0) but not in KKU-100 cells (combination index > 1.0). The combination treatments also increased the sub-G1 population and caused KKU-M214 cell cycle arrest at S and G2/M phases, which were the combined effects of cisplatin (S phase arrest) and peanut testa extracts (G2/M phase arrest). In addition, pERK1/2, Ac-H3, Bcl-2 and proteins related to apoptosis, including Bax and caspases 3, 8, 9, exhibited enhanced expression in KKU-M214 cells. The combination treatments caused down-regulation of p53, whereas the expression of p21 was fairly constant when compared with cisplatin single drug treatment. Conclusions: Peanut testa extracts in combination with cisplatin synergistically reduce cell viability and induce apoptosis through stimulation of caspases 3, 8 and 9 in KKU-M214 cells.

Functional implications of a psychiatric risk variant within CACNA1C in induced human neurons.

Psychiatric disorders have clear heritable risk. Several large-scale genome-wide association studies have revealed a strong association between susceptibility for psychiatric disorders, including bipolar disease, schizophrenia and major depression, and a haplotype located in an intronic region of the L-type voltage-gated calcium channel (VGCC) subunit gene CACNA1C (peak associated SNP rs1006737), making it one of the most replicable and consistent associations in psychiatric genetics. In the current study, we used induced human neurons to reveal a functional phenotype associated with this psychiatric risk variant. We generated induced human neurons, or iN cells, from more than 20 individuals harboring homozygous risk genotypes, heterozygous or homozygous non-risk genotypes at the rs1006737 locus. Using these iNs, we performed electrophysiology and quantitative PCR experiments that demonstrated increased L-type VGCC current density as well as increased mRNA expression of CACNA1C in iNs homozygous for the risk genotype, compared with non-risk genotypes. These studies demonstrate that the risk genotype at rs1006737 is associated with significant functional alterations in human iNs, and may direct future efforts at developing novel therapeutics for the treatment of psychiatric disease.