Joo-Il Kim

Induction of differentiation of the human histocytic lymphoma cell line U-937 by hypericin

Hypericin, a photosensitizing plant pigment, was found to be a potent inducer of differentiation of human myeloid leukemia U-937 cells. At a concentration of 0.2 µM, hypericin exhibited 50% growth inhibition. An effect on cell differentiation by hypericin was assessed by its ability to induce phagocytosis of latex particles, and to reduce nitroblue tetrazolium (NBT). Approximately 51% of 0.2 µM hypericin-treated cells were stained with NBT and 63% showed phagocytic activity. In order to establish whether hypericin induces differentiation of U-937 cells to macrophage or granulocyte, esterase activities and cell sizes were measured. When U-937 cells were treated with 0.2 µM and 0.15 µM of hypericin, the α-naphthyl acetate esterase activity was increased by 38.4% and 48.1%, respectively, but naphthol AS-D chloroacetate esterase activity was not influenced. The size of hypericin-treated cells in terms of cell mass was larger than that observed in untreated cells as determined by flow cytometry. Protein kinase C (PKC) inhibitor, NA-382, decreased the NBT reducing activity of hypericin, whereas a cAMP-dependent protein kinase A (PKA) inhibitor, H-89, did not show any influence on the differentiation. These results indicate that hypericin triggers differentiation toward monocyte/macrophage lineage by PKC stimulation.

Development and validation of an LC-MS/MS method for the determination of pelubiprofen and its active metabolite, trans-alcohol, in human plasma and its application to pharmacokinetic study

A suitable liquid chromatography tandem mass spectrometry (LC-MS/MS) method is required to determine pelubiprofen and its active metabolite, trans-alcohol (M-D), in human plasma for pharmacokinetic studies of pelubiprofen preparations. After one-step liquid-liquid extraction (LLE) using methyl tert-butyl ether (MTBE), pelubiprofen, M-D, and tolbutamide (the internal standard, IS) were eluted from a Capcellpak C18 ACR column using a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile at a flow rate 0.35mL/min. The achieved lower limits of quantitation (LLOQ) of pelubiprofen and M-D were both 15ng/mL (S/N>10) and the standard calibration curves for pelubiprofen and M-D were linear (correlation coefficients >0.99) over the studied concentration range (15-2000ng/mL). Intra- and inter-day precisions were within 7.62% for all analytes and the deviation of assay accuracies was within ±13.23%. The developed method was successfully applied to a pharmacokinetic study of pelubiprofen in healthy Korean male volunteers.

Compound K induced apoptosis via endoplasmic reticulum Ca2+ release through ryanodine receptor in human lung cancer cells

Background Extended endoplasmic reticulum (ER) stress may initiate apoptotic pathways in cancer cells, and ER stress has been reported to possibly increase tumor death in cancer therapy. We previously reported that caspase-8 played an important role in compound K-induced apoptosis via activation of caspase-3 directly or indirectly through Bid cleavage, cytochrome c release, and caspase-9 activation in HL-60 human leukemia cells. The mechanisms leading to apoptosis in A549 and SK-MES-1 human lung cancer cells and the role of ER stress have not yet been understood. Methods The apoptotic effects of compound K were analyzed using flow cytometry, and the changes in protein levels were determined using Western blot analysis. The intracellular calcium levels were monitored by staining with Fura-2/AM and Fluo-3/AM. Results Compound K-induced ER stress was confirmed through increased phosphorylation of eIF2α and protein levels of GRP78/BiP, XBP-1S, and IRE1α in human lung cancer cells. Moreover, compound-K led to the accumulation of intracellular calcium and an increase in m-calpain activities that were both significantly inhibited by pretreatment either with BAPTA-AM (an intracellular Ca2+ chelator) or dantrolene (an RyR channel antagonist). These results were correlated with the outcome that compound K induced ER stress-related apoptosis through caspase-12, as z-ATAD-fmk (a specific inhibitor of caspase-12) partially ameliorated this effect. Interestingly, 4-PBA (ER stress inhibitor) dramatically improved the compound K-induced apoptosis. Conclusion Cell survival and intracellular Ca2+ homeostasis during ER stress in human lung cancer cells are important factors in the induction of the compound K-induced apoptotic pathway.

Pharmacokinetic Interactions Between Pelubiprofen and Eperisone Hydrochloride: A Randomized, Open-label, Crossover Study of Healthy Korean Men

PURPOSE Pelubiprofen is a novel nonsteroidal anti-inflammatory, analgesic, and antipyretic drug with at least similar efficacy and better tolerability compared with other nonsteroidal anti-inflammatory, analgesic, and antipyretic drugs such as naproxen and aceclofenac. Eperisone hydrochloride is a centrally acting muscle relaxant that performs by blocking calcium channels. The combined use of pelubiprofen and eperisone hydrochloride is increasingly anticipated to promote the clinical effectiveness of pelubiprofen in relieving musculoskeletal symptoms of osteoarthritis, rheumatoid arthritis, and low back pain. No published data are yet available, however, regarding the pharmacokinetic interactions between these 2 drugs when administered concurrently. The objective of this study was to evaluate any pharmacokinetic interactions between pelubiprofen and eperisone hydrochloride in healthy Korean male volunteers. METHODS This was a randomized, open-label, crossover study. Each participant was randomly assigned to 1 of 6 treatment sequences and orally received either 45-mg sustained-release pelubiprofen, 75-mg sustained-release eperisone hydrochloride, or both as a single dose in each treatment period, with a 7-day washout period between each treatment. Serial blood samples were collected over 24 hours after dosing, and plasma concentrations of each drug and the major active metabolite of pelubiprofen (trans-alcohol pelubiprofen) were determined by using a validated HPLC-MS/MS system. Pharmacokinetic analyses were conducted by using noncompartmental methods. FINDINGS A total of 24 men (mean ± standard deviation of: age, 29 ± 4 years; weight, 72.5 ± 7.8 kg; body mass index, 23.4 ± 1.9 kg/m2) were enrolled, and 23 participants completed the study. For pelubiprofen, the geometric mean ratios (90% CIs) of Cmax and AUC0-∞ were 1.02 (0.87-1.19) and 0.97 (0.88-1.07), respectively. For the major active metabolite of pelubiprofen (trans-alcohol pelubiprofen), the geometric mean ratios (90% CIs) of Cmax and AUC0-∞ were 1.05 (0.98-1.13) and 1.04 (1.01-1.07). For eperisone, the geometric mean ratios (90% CIs) of Cmax and AUC0-∞ were 0.87 (0.67-1.15) and 1.05 (0.85-1.30). None of the study participants experienced serious adverse events during the study. IMPLICATIONS No clinically significant changes were noted in the pharmacokinetic interactions of pelubiprofen, the major active metabolite of pelubiprofen (trans-alcohol pelubiprofen), and eperisone hydrochloride between monotherapy and combination therapy with 45-mg sustained-release pelubiprofen and 75-mg sustained-release eperisone hydrochloride.