• Archives of Pharmacal Research
• /
• v.25 no.5
• /
• pp.655-663
• /
• 2002

Liver fibrosis is a prepathological state wherein damaged liver tissues in chronic liver diseases, such as hepatitis, are not repaired to normal tissues, but converted to fibrous tissue. 5-(2-Pyrazinyl)-4-methyl-1,2-dithiol-3-thione (oltipraz), a cancer chemopreventive agent, is effective against a wide variety of chemical carcinogens. Recently, we reported that oltipraz inhibits liver fibrogenesis (Kang et al., 2002). In the present study, the effects of oltipraz in combination with dimethyl-4,4'-dimethoxy-5,6,5',6'-dimethylene dioxybiphenyl-2,2'-dicarboxylate (DDb) on dimethylnitrosamine (DMN)-induced liver fibrogenesis were assessed in rats. Oltipraz (30 mg/kg body weight, po, 3 times per week for 4 weeks) was found to inhibit the increases in plasma ALT, AST and bilirubin by DMN, whereas DDB (30 mg/kg body weight, po, 3 times per week for 4 weeks) attenuated the increases in the plasma ALT and bilirubin. The lowered plasma protein and albumin contents in DMN-treated rats were completely restored by oltipraz, but not by DDB. DDB decreases liver cell injury and inflammation through inhibition of nuclear factor-kB. DMN increased the accumulation of liver collagen, as indicated by the increase in the 4-hydroxyproline content in liver homogenates, which was reduced by treatment with oltipraz, but not by DDB. Given the differential effect between oltipraz and DDB, the potential enhancement of antifibrotic efficacy by the drugs was assessed in the animal model. Despite the minimal effect of DDB on DMN-induced fibrogenesis, DDB (5-25 mg/kg), administered together with oltipraz (25-5 mg/kg), showed an additive protective effect against hepatotoxicity and fibrosis induced by DMN, which was shown by the blood chemistry parameters and histopathological analysis. The adequate composition ratio of oltipraz to DDB was 5:1. These results provide information on the pharmaceutical composition, comprising of oltipraz and DDB as the active components, for the treatment and/or prevention of liver fibrosis and cirrhosis.

• Archives of Pharmacal Research
• /
• v.25 no.5
• /
• pp.718-723
• /
• 2002

CKD-602 (7-[2-(N-isopropylamino)ethyl]-(20S)-camptothecin) is a recently-developed synthetic camptothecin analogue and currently under clinical development by Chong Kun Dang Pharm (Seoul, Korea). CKD-602 showed potent topoisomerase inhibitory activity in vitro and broad antitumor activity against various human tumor cells in vitro and in vivo in animal models. This study describes the pharmacodynamics of the immediate and delayed cytotoxicity induced by CKD-602 in a human colorectal adenocarcinoma cell line, HT-29, and its intracellular drug accumulation by HPLC. The present study was designed to address whether the higher activity of CKD-602 with prolonged exposure is due to delayed exhibition of cytotoxicity and/or an accumulation of anti proliferative effect on continuous drug exposure. The drug uptake study was performed to determine whether the delayed cytotoxicity is due to a slow drug accumulation in cells. CKD-602 produced a cytotoxicity that was exhibited immediately after treatment (immediate effect) and after treatment had been terminated (delayed effect). Both the immediate and delayed effects of CKD-602 showed a time dependent decrease in 4IC_{50}$ values. Drug uptake was biphasic and the second equilibrium level was obtained as early as at 24hr, indicating that the cumulative and delayed antitumor effects of CKD-602 were not due to slow drug uptake. On the other hand, CKD-602 treatment was sufficient to induce delayed cytotoxicity after 4hr, however, longer treatment (＞24hr) enhanced its cytotoxicity due to the intracellular accumulation of the drug, which requires 24hr to reach maximum equilibrium concentration. In addition, $C^n$$\times$T=h analysis (n=0.481) indicated that increased exposure times may contribute more to the overall antitumor activity of CKD-602 than drug concentration. Additional studies to determine the details of the intracellular uptake kinetics (e.g., concentration dependency and retention studies) are needed in order to identify the optimal treatment schedules for the successful clinical development of CKD-602.

• Archives of Pharmacal Research
• /
• v.25 no.5
• /
• pp.685-690
• /
• 2002

The mitogen-stimulated serine/threonine kinase $p70^{S6k}$ plays an important role in the progression of cells from $G_0/G$_1$$ to S phase of the cell cycle by translational up-regulation of a family of mRNA transcripts family of mRNA transcripts which contain polypyrimidine tract at their 5 transcriptional start site. Here, we report that $p70^{S6k}$ was constitutively phosphorylated and activated to various degrees in serum-deprived AGS, A2058, HT-1376, MG63, MCF7, MDA-MB-435S, MDA-MB-231 and MB-157. Rapamycin treatment induced a significant dephosphorylation and inactivation of $p70^{S6k}$ in all cancer cell lines, while wortmannin, a specific inhibitor of PI3-K, caused a mild dephosphorylation of $p70^{S6k}$ in AGS, MDA-MB-435S and MB-157. In addition, SQ20006, methylxanthine phosphodiesterase inhibitor, reduced the phosphorylation of $p70^{S6k}$ in all cancer cells tested. Consistent with inhibitory effect of rapamycin on $p70^{S6k}$ activity, rapamycin inhibited [$^3H$]-thymidine incorporation and increased the number of cells at $G_{0}G_{1}$ phase. Furthermore, these inhibitory effects were accompanied by the decrease in growth of cancer cells. Taken together, the results indicate that the antiproliferative activity of rapamycin might be attributed to cell cycle arrest at $G_{0}G_{1}$ phase in human cancer cells through the inhibition of constitutively activated $p70^{S6k}$ of cancer cells and suggest $p70^{S6k}$ as a potential target for therapeutic strategies aimed at preventing or inhibiting tumor growth.

• Archives of Pharmacal Research
• /
• v.26 no.2
• /
• pp.168-172
• /
• 2003

Radiation synovectomy is one of the most useful methods for treating patients with refractory synovitis because of its convenience, long-term effects, repeatability and the avoidance of surgery. In this study, we investigated the toxicity, stability and biodistribution of a rhenium-188 ($^{188}$Re)-tin colloid to evaluate its suitability as a synovectomy agent. Twenty four hours after injecting the $^{188}$Re-tin colloids (74 KBq/0.1 mL) into the tail vein of ICR mice, most of the $^{188}$Retin colloidal particles was found in the lungs. In addition, there were no particle size changes at either room temperature or at $37^{\circ}C$ after injecting the $^{188}$Re-tin colloids in human plasma and synovial fluid. In vitro stability tests showed that the $^{188}$Re-tin colloid remained in a colloidal form without a critical size variation over a 2-day period. We investigated the leakage of $^{188}$Retin colloids from the intraarticular injection site with gamma counting in New Zealand white rabbits. The $^{188}$Re-tin colloids (55.5 MBq/0.15 mL) were injected at the cavum articular and the mean retention percentage of the $^{188}$Re-tin colloid was 98.7% for 1 day at the injection site, which suggests that there was neither change in the particle size nor leakage at the injection sites. In the biodistribution study with the SD rats, the liver showed the highest radioactivity (0.0427% ID/organ) except for the injected knees (99.49%). In the SD rats, mild toxicities including the skin or a synovium inflammation were observed as a result of a radioactivity of 15 mCi/kg at the intraarticular injection site. However, there was no systemic toxicity. In the Ovalbumin (OVA)-induced arthritic rabbits, the $^{188}$Re-tin colloid improved the macroscopic, the histological score and reduced the knee joint diameter when compared to the arthritic control. In conclusion, a $^{188}$Re-tin-colloid is considered as a strong candidate for radiation synovectomy with a superior efficacy and safety.

• Archives of Pharmacal Research
• /
• v.28 no.5
• /
• pp.626-635
• /
• 2005

Liposome as a carrier of topotecan (TPT), a promising anticancer drug, has been reported in attempt to improve the stability and antitumor activity of TPT. However, the biodistr ibution pattern of TPT liposome in vivo and PEG-modified liposome containing TPT have not been studied systemically. In this paper, the in vitro stability and in vivo biodistribution behavior of several liposomes containing TPT with different lipid compositions and PEG-modification were studied. Compared with the 'fluid' liposome (S-Lip) composed of soybean phosphatidylcholine (SPC), the 'solid' liposome (H-Lip) composed of hydrogenated soybean phosphatidylcholine HSPC decreased the leaking efficiency of TPT from liposome and enhanced the stability of liposome in fetal bovine serum (FBS) or human blood plasma (HBP). The results of biodistribution studies in S$_{180}$ tumor-bearing mice showed that liposomal encapsulation increased the concentrations of total TPT and the ratio of lactone form in plasma. Compared with free TPT, S-Lip and H-Lip resulted in 5- and 19- fold increase in the area under the curve (AUC$_{0\rightarrow\propto}$), respectively. PEG- modified H-Lip (H-PEG) showed 3.7-fold increase in AUC$_{0\rightarrow\propto}$ compared with H-Lip, but there was no significant increase in t$_{1/2}$ and AUC$_{0\rightarrow\propto}$ for PEG-modified S-Lip (S-PEG) compared with S-Lip. Moreover, the liposomal encapsulation changed the biodistribution behavior, and H-Lip and H-PEG dramatically increased the accumulation of TPT in tumor, and the relative tumor uptake ratios were 3.4 and 4.3 compared with free drug, respectively. There was also a marked increase in the distribution of TPT in lung when the drug was encapsulated into H-Lip and H-PEG. Moreover, H-PEG decreased the accumulation of TPT in bore marrow compared with unmodified H-Lip. All these results indicated that the membrane fluidity of liposome has an important effect on in vitro stability and in vivo biodistribution pattern of liposomes containing TPT, and PEG-modified 'solid' liposome may be an efficient carrier of TPT.

• Archives of Pharmacal Research
• /
• v.16 no.3
• /
• pp.244-250
• /
• 1993

Calli and suspension cultures were obtained following inoculation of the explant from leaves of Ginkgo biloba L on the supplemented MS basal medium. The obtained calli and suspension cultured cells were able to produce detectable amounts of ginkgolides which are known as natural specific PAF antagonists. The production of ginkgolides in the calli and suspension cultured celles were identified using GC/MS, GC and HPLC with authentic ocmpounds. Since the production of ginkgolides A and B the calli and suspension cultured cells had been confirmed, effects of types and concentration of plant growth regulators, media and illumination on the induction and growth of the callus were studied. The concentrations of growth regulators for optimal callus were studied. The concentrations of growth regulators for optimal callus induction were studied. The concentrations of growth regulators for optimal callus induction were 1.0 to 2.0 mg/L for NAA and o.1 mg/L for kinetin. The growth of the Callus seemed to be more simnultaed with the combination of NAA and kinetin than NAA and BA with illumination at all concentration ranges of 1.0 to 4.0 mg/l for NAA and o.1 to 1.0 mg/L for kinetin or BA studied. Amogn 8 different media used, the induction rate of callus on Anderson, Eriksson, and Shenk and Hildebrant at 4 weeks after the innoculation was almost the same as that of MS. However, callus was rarely induced on Heller or White medium. Suspension cultures were easily initiated with 3 g of callus (fresh weight) derived from ginkgo leaves on supplemented MS medium. A typical growth curve of suspension cultured cells could be obtained by measuring the fresh weight of the suspension cultured cells at every 3 days. To improve the growth of suspension cultured cells of ginkgo, effects of concentrations of NAA, sucrose, phosphate ions and molar ratio of $NH_{4}^+\;to\;NO_{3}^-$ ions in the culture medium were studied. The maximum growth of the cells was achieved when the culture medium contained 1.0 mg/L of NAA, 30 g/L sucrose, 1.75 mM phosphate ions and 1:5 molar ratio of $NH_{4}\;to\;NO_{3}^-$ ions.

• Archives of Pharmacal Research
• /
• v.22 no.4
• /
• pp.354-360
• /
• 1999

Inflammatory bowel disease (IBD) is a multifactorial disorder with unknown etiology and pathogenesis. DA-6034,$ 7-carboxymethyloxy-3^{l}, 4^{l},$ 5-trimethoxy flavone, is a synthetic flavonoid known to possess anti-inflammatory activity. This study was performed to evaluate the oral therapeutic effect of DA-6034 in three experimental animal models of IBD : two chemical-induced IBD models of rats and the human leukocyte antigen (HLA)-B27 transgenic rat model known to develop spontaneous colitis without the use of exogenous agents. Acute chemical colitis was induced by intracolonic instillation of 1.2 ml of 4% acetic acid solution. Prednisolone (1 mg/kg), sulfasalazine (100 mg/kg) and DA-6034 (0.3~3 mg/kg) were orally administered twice daily for 6 days in these rats. In addition, chronic chemical colitis was induced by intracolonic administration of trinitrobenzene sulfonic acid (TNBS) 30 mg in 50% ethanol and agents were orally administered for 6 or 20 days. In chemical-induced IBD models, all of these agents reduced the severity of colitis and specially, DA-6034 (3 mg/kg) showed more potent effect than other drugs in macroscopic lesion score. In HLA-B27 transgenic rats, DA-6034 (3 mg/kg) and prednisolone (0.5 gm/kg) were treated orally twice daily for 6 weeks. The HLA-B27 transgenic rats showed only mild colitis, compared with the chemical-induced colitis models. DA-6034 ameliorated the loose stool and decreased microscopic damage, which is the important indicator of this model. In conclusion, oral therapy of DA-6034 attenuated the macroscopic and histologic damages of the colon in all three experimental models of IBD, which suggest that DA-6034 could be a promising drug in the treatment of IBD.

• Archives of Pharmacal Research
• /
• v.18 no.6
• /
• pp.410-414
• /
• 1995

Adaptive response induced by low dese .gamma.-ray irradiation in human cervical carcinoma cells was examined. Cells were exposured to low dose of .gamma.-ray irradiation in human cervical carcinoma cells was examined. Cells were exposured to low dose of .gamma.-ray (1-cGy) followed by high doses of r-ray irradiation (0,1,2,3,5,7 and 9Gy for chlnogenic assay or 1.5Gy for micronucleus assay) with various time intervals. Survival fractions of cells in both low dose-irradiated and unirrated groups were analyzed by clonogenic assay. Surviva fractions of low dose-irradiated in cell survival was maximum when low and high dose irradiation time interval was 4 hr. Frequencies of micronuclei which is an indicative of chromosome aberration were also enutained from survival fractions analyzed by clonogenic assay, maximum when low and high dose irradiation time interval was 4hr. Frequencies of micronuclei which is an indicative of chromosome aberration were also enumerated in both low dose-irradiated and unirradiated groups. In consiststent with the result obtained from survival fractions analyzed by clonogenic assay, maximum reduction in frquencies of micronuclei was observed when low dose radiation was given 4 hr prior to high response to subsequent high dose .gamma.-ray irradiation in human cervical carcinomal cells. Our data suggest that one of the possible mechanisms of adaptive response induced by low dose rediation is the increase in repair of DNA double strand breaks in low dose radiation-adapted cells.

• Archives of Pharmacal Research
• /
• v.28 no.11
• /
• pp.1287-1292
• /
• 2005

KR-33028 (N-[4-cyano-benzo[b]thiophene-2-carbonyl]guanidine) is a new cardioprotective agent for preventing ischemia-reperfusion injury. This study was performed to identify the metabolic pathway of KR-33028 in human liver microsomes and to compare its metabolism with that of cryopreserved human hepatocytes. Human liver microsomal incubation of KR-33028 in the presence of NADPH and UDPGA resulted in the formation of four metabolites, M1, M2, M3, and M4. M1 and M2 were identified as 5-hydroxy-KR-33028 and 7-hydroxy-KR-33028, respectively, on the basis of LC/MS/MS analysis with the synthesized authentic standard. M3 and M4 were suggested to be dihydroxy-KR-33028 and hydroxy-KR-33028-glucuronide, respectively. Metabolism of KR-33028 in cryopreserved human hepatocytes resulted in the formation of M1, M2, and M4. These data show a good correlation between major metabolites formed in human liver microsomes and cryopreserved human hepatocytes. In addition, KR­33028 was found to inhibit moderately the metabolism of CYP1A2 substrates. Based on the results obtained metabolic pathway of KR-33028 is proposed.

• Archives of Pharmacal Research
• /
• v.23 no.4
• /
• pp.353-359
• /
• 2000

${\alpha}_2$-Adrenoceptor antagonists, which can enhance synaptic norepinephrine levels by blocking feedback inhibition processes, are potentially useful in the treatment of disease states such. as depression, memory impairment, impotence and sexual dysfunction. (10bS)-1,2,3,5,6,10b-Hexahydropyrrolo[2,1-a]isoquinoline oxalate (YSL-3S) was evaluated in several in vitro biological tests to establish its pharmacological profile of activities as an ${\alpha}_2$-adrenoceptor antagonist. Saturation binding assay revealed that$^{3}[H]$rauwolscine bound to the $\alpha$$_2$-adrenoceptors with a Kd value of 6.3$\pm$0.5 nM and a Bmax value of 25l$\pm$39 fmol/mg protein in rat cortical synaptic membranes. Competitive binding assay showed that YSL-3S inhibited the binding of$^3[H]$rauwolscine (1 nM) in a concentration-dependent manner with a Ki value of 98.2$\pm$12.1 nM while it did not inhibit the binding of [$^3$H]cytisine (1.25 nM) to neuronal nicotinic cholinergic receptors. The Ki values of yohimbine, clonidine and norepinephrine for $^3[H]$rauwolscine binding were 15.8$\pm$1.0, 40.1$\pm$5.9 and 40.0$\pm$11.5 nM, respectively. In addition, the binding affinity of YSL-3S for ${\alpha}_2$-adrenoceptors was higher than that of its antipode and the racemic mixture. The functional activity of YSL-3S at the presynaptic ${\alpha}_2$-adrenoceptors was assessed using the prostatic portion of the rat vas deferens. Clonidine inhibited field-stimulated contractions of the vas deference in a dose-dependent manner. The presence of YSL-3S or yohimbine caused a parallel, rightward the dose-response curve of clonidine in a dose-dependent manner, indicating an antagonistic action at the presynaptic ${\alpha}_2$-adrenoceptors. The $pA_2$values of yohimbine and YSL-3S were 7.66$\pm$0.13 and 6.64$\pm$0.18, respectively. The results indicate that YSL-3S acts as a competitive antagonist at presynaptic ${\alpha}_2$ -adrenoceptors with a potency approximately ten times lower than yohimbine, but is devoid of binding affinity for neuronal nicotinic cholinergic receptors.