Isolation, synthesis and absolute configuration of 4,5-dihydroxypiperines improving behavioral disorder in AlCl3-induced dementia.

A pair of stereoisomers of new 4,5-dihydroxypiperine was isolated from P. retrofractum and showed profound activity on AlCl3-induced dementia. In order to determine their absolute configurations and biological activities, all four possible stereoisomers of 4,5-dihydroxypiperine were synthesized from piperidine by Sharpless asymmetric dihydroxylation and Mitsunobu reaction. Their absolute configurations were established as (4R,5R) (1), (4S,5S) (2), (4S,5R) (3) and (4R,5S) (4) by NMR, optical rotation and CD spectra. It is note that only compound 4 improved behavioral disorder in AlCl3-induced dementia. Accordingly, the pair of stereoisomers isolated from P. retrofractum was determined to be (4S,5S) and (4R,5S)-isomers (2 and 4). The ratio of the epimers was present as 1:0.7 (4:2).

The opioid receptor triple agonist DPI-125 produces analgesia with less respiratory depression and reduced abuse liability.

Opioid analgesics remain the first choice for the treatment of moderate to severe pain, but they are also notorious for their respiratory depression and addictive effects. This study focused on the pharmacology of a novel opioid receptor mixed agonist DPI-125 and attempted to elucidate the relationship between the δ-, µ- and κ-receptor potency ratio and respiratory depression and abuse liability. Five diarylmethylpiperazine compounds (DPI-125, DPI-3290, DPI-130, KUST202 and KUST13T02) were selected for this study. PKA fluorescence redistribution assays in CHO cells individually expressing δ-, µ- or κ-receptors were used to measure the agonist potency. The respiratory safety profiles were estimated in rats by the ratio of ED50 (pCO2 increase)/ED50 (antinociception). The abuse liability of DPI-125 was evaluated with a self-administration model in rhesus monkeys. The observed agonist potencies of DPI-125 for δ-, µ- and κ-opioid receptors were 4.29±0.36, 11.10±3.04, and 16.57±4.14 nmol/L, respectively. The other four compounds were also mixed agonists with varying potencies. DPI-125 exhibited a high respiratory safety profile, clearly related to its high δ-receptor potency. The ratio of the EC50 potencies for the µ- and δ-receptors was found to be positively correlated with the respiratory safety ratio. DPI-125 has similar potencies for µ- and κ-receptors, which is likely the reason for its reduced abuse potential. Our results demonstrate that the opioid receptor mixed agonist DPI-125 is safer and less addictive than traditional µ-agonist analgesics. These findings suggest that the development of δ>µâˆ¼κ opioid receptor mixed agonists is feasible, and such compounds could represent a promising class of potent analgesics with wider therapeutic windows.

Caspase-8 knockdown suppresses apoptosis, while induces autophagy and chemo-sensitivity in non-small cell lung cancer cells.

PURPOSE: Drug resistance remains a major cause of relapse and therapeutic failure in non-small cell lung cancer (NSCLC). The purpose of this investigation is to explore the relationship between caspase-8 level and chemo-sensitivity, as well as its underlying mechanism in NSCLC cells. METHODS: NSCLC cell line, A549 cells was used to investigate the influence of caspase-8 on the biological behavior in vitro. The abundance of caspase-8 in A549 cells was manipulated by transfection lentivirus containing specific caspase-8 short hairpin RNA (sh-caspase-8) and caspase-8 overexpressed plasmid. Cell viability and the percentage of apoptotic cells was quantified using cell counting kit-8 (CCK-8) assay and flow cytometry following Annexin V-FITC/PI staining, respectively. The formation of acidic vesicle organelles (AVOs) was examined by acridine orange staining and visualized under a fluorescence microscope. The mRNA and protein levels of relative genes were determined by qRT-PCR and western blotting. RESULTS: Our results indicated that cells infected with sh-caspase-8 exhibited high knockdown efficiency. Knockdown of caspase-8 significantly reduced apoptosis of A549 cells. As evidenced by the decreased number of apoptotic cells and the reduction of Bcl-2/bax ratio. Interestingly, caspase-8 knockdown also enhanced autophagy in A549 cells. Additionally, knockdown of caspase-8 reduced the doxorubicin, carboplatin, cisplatin, and etoposide sensitivity towards A549 cells. CONCLUSION: In summary, our results revealed that knockdown of caspase-8 could promote cell growth and autophagy, while reduce chemo-sensitivity and apoptotic cell death. These finding suggest caspase-8 might serve as a potential target to improve the chemo-sensitivity for NSCLC patients in clinical setting.