Steady-state bioequivalence study of clozapine tablet in schizophrenic patients

PURPOSE

To compare the bioavailability of two clozapine formulations (100 mg Clozaril tablet from Novartis Pharmaceuticals UK Ltd., UK, as a Reference formulation and 100 mg Cloril tablet from Atlantic Laboratories Corp., Ltd., Thailand, as a Test formulation). The present study was conducted under real-life conditions in schizophrenic patients using a steady-state, multiple-dose, randomized crossover design to avoid the risk of adverse effects in healthy volunteers and pharmacokinetic difference between single and multiple-dose of the drug.

METHODS

The subjects received 100 mg bid of either the Reference formulation or the Test formulation for 7 days. At day-7 of each study phase, blood samples were collected at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10 and 12 h after drug administration. Plasma was separated and stored at -80 degrees C until assay. The plasma concentration of clozapine was determined by high performance liquid chromatography. Pharmacokinetic parameters were calculated from the observed plasma-concentration time profiles. The bioequivalence between the two formulations was assessed by calculating individual peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC(0-12 h)) ratios.

RESULTS

All subjects well tolerated both clozapine formulations. No serious side effects were reported. The Tmax, terminal half-life and the total plasma clearance of clozapine (uncorrected for bioavailability) observed in the present study were comparable to those observed in other previous reports. All of the pharmacokinetic parameters investigated in the present study calculated from the subjects after administration of Test and Reference formulations were close. The 90% confident interval for the ratio of means for the lnCmax (0.9784-1.0622) and lnAUC(0-12h) (0.9559-1.0441) are within the guideline range of bioequivalence (0.80 to 1.25).

CONCLUSION

The result demonstrated that the Test formulation was bioequivalent to the Reference formulation (Clozaril) when orally administered in schizophrenic patients, in terms of both the rate and extent of absorption.

Mechanism of ketoconazole-induced elevation of individual serum bile acids in the rat: relationship to the effect of ketoconazole on bile acid uptake by isolated hepatocytes

Ketoconazole, an imidazole derivative, has been implicated in a number of hepatic dysfunctions. The aim of the present study was to determine the effect of in vivo treatment of rats with ketoconazole on individual serum bile acid levels and the in vitro effects of ketoconazole on the hepatocellular uptake of two bile acids and two other model substrates transported by liver cells. Male Sprague-Dawley rats were treated i.p. with a single injection of ketoconazole of 25 mg/kg (n = 4) or 50 mg/kg (n = 4); the control group (n = 4) received the vehicle only at a dose of 1 ml/kg. Blood samples were collected at 4 hr after dosing. With high-performance liquid chromatography, the serum was assayed for individual serum bile acids. At the higher dose, ketoconazole produced a significant increase in serum levels of cholic acid, taurocholic acid, chenodeoxycholic acid, glycocholic acid, glycochenodeoxycholic acid, glycodeoxycholic acid, deoxycholic acid and taurochenodeoxycholic acid compared with the control group (P < .05). Cholic acid, taurocholic acid and chenodeoxycholic acid levels were significantly raised in rats treated with the lower dose. In vitro, ketoconazole strongly inhibited the hepatocellular uptake of [14C]cholic acid, [14C]taurocholic acid and [3H]ouabain but not [14C]2-aminoisobutyric acid, which indicated that the effect is relatively specific. The kinetics of inhibition were competitive and the inhibition constants for taurocholate and ouabain were 6 and 1 microM, respectively. Ketoconazole inhibited by both Na(+)-dependent taurocholate uptake and stimulated bile acid countertransport of preloaded hepatocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-tumor activity of rice bran hydrolysates on migration, invasion and angiogenesis

Objective:

To investigate anti-tumor effect of rice bran hydrolysates (RBH) on proliferation, migration, invasion, and angiogenesis of cholangiocarcinoma (CCA) cells, and elucidate the underlying mechanisms.

Methods:

RBH was prepared from Tubtim Chumprae rice (Oryza sativa L.) by hydrothermolysis followed by protease digestion. Phenolic content in RBH was analyzed by high-performance liquid chromatography. Human CCA cells, KKU-156, KKU-452, and KKU-100, were used to study the effects of RBH on proliferation, migration, invasion, and adhesion by wound healing, Transwell chamber, and fibronectin cell adhesion assays. Angiogenesis was evaluated using human umbilical vein endothelial cells. Proteins associated with cancer progression were analyzed by immunobloting assays.

Results:

RBH contained carbohydrates, proteins, lipids, and various phenolic compounds and flavonoids. RBH did not inhibit CCA proliferation, but strongly suppressed migration, invasion, adhesion of CCA cells, and the formation of tube-like capillary structures of human umbilical vein endothelial cells. Moreover, RBH down-regulated phosphorylation of FAK, PI3K, and Akt, suppressed NF-κB nuclear translocation, decreased the expression of ICAM-1, vimentin and vascular endothelium growth factor (VEGF), and increased the expression of E-cadherin.

Conclusions:

RBH suppresses CCA cell migration and invasion and decreases expression of proteins involved in cancer metastasis. RBH is a potential food supplement for cancer prevention.

Establishment and genomic profiling of cholangiocarcinoma cells with functional characterization

Cholangiocarcinoma (CCA) is a highly lethal hepatobiliary malignancy, with prognosis is influenced by anatomical subtypes and etiological factors. This study successfully established three CCA cell lines: KKU-097, KKU-466, and KKU-610, from the primary tumors of patients in liver fluke-endemic areas. These cells represent the perihilar CCA (pCCA) and intrahepatic CCA (iCCA) subtypes. Comprehensive analyses, including histopathology, molecular profiling, biomarkers, cancer phenotype characterization, and drug sensitivity testing with standard chemotherapeutics, were conducted. Whole-exome sequencing was performed to explore genetic alterations. All three cell lines exhibited adherent growth with an epithelial morphology and positive expression of the bile duct epithelial markers CK-7 and CK-19. Cytogenetic analysis revealed highly complex hypertriploid karyotypes with multiple chromosomal aberrations. Among the cell lines, KKU-610 demonstrated higher growth and invasion rates, whereas KKU-466 and KKU-097 cells exhibited less aggressive phenotypes. Drug sensitivity testing demonstrated relative resistance to gemcitabine as a monotherapy and in combination with cisplatin in all three cells. Genomic profiling identified targetable mutations, highlighting these new cell lines as valuable models for investigating the pathogenesis of CCA and evaluating therapeutic strategies.

Alendronate blocks human cholangiocarcinoma cell proliferation and migration

Purpose: To explore the effect of alendronate on cell death and migration of cholangiocarcinoma (CCA). Methods: Migration and cell death of CCA cells were determined using sulforhodamine B (SRB), colony formation, wound healing, and gelatin zymography assays. The mechanism of action of alendronate was studied with reverse-transcriptase polymerase reaction (RT-PCR) for gene expression and by Western blotting analysis for protein expression. Results: Alendronate stimulated KKU-100 cell death in dose- and time-dependent manner, with low IC50 value, and significantly inhbited colony formation at doses of 5 - 100 µM. Moreover, alendronate at doses of 250 - 1000 µM significantly stimulated CCA apoptosis via reactive oxygen species (ROS) generation, and enhanced caspase 3 activity at a dose of 1000 µM. Moreover, at a dose of 250 µM, it significantly inhibited cell growth through induction of caspase 3 and p53, and reduction of protein expression levels of NF-ĸB. Furthemore, alendronate altered mevalonate (MVA) pathway via downregulation of Rac1 protein expression. In contrast, it significantly inhibited CCA cell migration, and reduced MMP 2 and MMP 9 levels at doses of 25 - 100 µM. Conclusion: Alendronate may be useful as a novel drug for prevention and chemotherapy of CCA.

Cytotoxicity against Cholangiocarcinoma and HepG2 Cell Lines of Lignans from Hernandia nymphaeifolia

Eleven lignans (1-11) were isolated from the seed of Hernandia nymphaeifolia. Most of the lignans exhibited strong to moderate cytotoxicity against cholangiocarcinoma KKU-M156 and HepG2 cell lines. Compounds 4 and 8 showed cytotoxicity against the KKU-M156 cell line with IC50 values of 5.2 μ M (Emax 96%) and 5.4 (Emax 59%) μM, respectively. In the cases of cytotoxicity against the HepG2 cell line, compounds 2, 3, 4, and 8 showed cytotoxicity with IC50 values of 1.7 M (Emax 84%), 4.1 μM (Emax 74%), 4.5 μM (Emax 68%), and 5.2 μM (Emax 78%), respectively.

Evaluation of efficacy, safety and tolerability of high dose-intermittent calcitriol supplementation to advanced intrahepatic cholangiocarcinoma patients--a pilot study

Antitumor activity (growth suppression) of vitamin D has been demonstrated using cholangiocarcinoma (CCA) cell lines, CCA cell-grafted animal models, and human CCA tissue cultures. The present study aimed to determine the toxicity and tolerability of intermittent-high dose calcitriol in advanced inoperable intrahepatic CCA patients and to evaluate the therapeutic efficacy of combinations of calcitriol and 5-fluorouracil-based chemotherapeutic drugs. The patients were divided into 3 groups: the first (n=2) received intermittent-high dose oral calcitriol 12 μg/day for 3 days, i.e. Monday-Wednesday, per week up to 3 months. The treatment did not cause any serious adverse events, except hypercalcemia grade I, once in 72 administrations. The second group (n=3) received chemotherapeutic drugs (5-fluorouracil, Mitomycin C and Leucovorin) for 3 cycles, one patient showing a partial response. The third group (n=4) received high dose calcitriol in combination with chemotherapeutic-drugs. All 4 patients encountered serious adverse events and two of them were withdrawn after the first drug cycle. This pilot study suggests that, although high dose-intermittent calcitriol appeared to be safe and tolerated well in advanced intrahepatic CCA patients, co-administration with 5-fluorouracil-based chemotherapeutic drugs caused unexpected potentiation of their toxicity. Adjustment of the doses of both drugs is required to avoid such toxicity and to optimize therapeutic efficacy of anticancer drugs when they were combined with high dose-intermittent calcitriol.

Fisetin-induced cell death, apoptosis, and antimigratory effects in cholangiocarcinoma cells

Fisetin is a plant flavonol that can be discovered in vegetables and fruits and it has been related to certain anticancer properties. It may prevent metastasis, reduce tumor cell proliferation, and stimulate apoptosis. Fisetin may inhibit cholangiocarcinoma (CCA) cell migration and proliferation; however, its exact actions are still less information. The aim of the current study was to examine the actions of fisetin on two types of CCA cells, KKU-100, and KKU-M452, in terms of their ability to proliferate, undergo apoptosis, and migrate. The fisetin effect on cell growth was determined using sulforhodamine B, colony-forming ability, and distribution of cell cycle method. The apoptotic induction was explored by acridine orange/ethidium bromide (AO/EB) staining assay. Migratory suppression was determined by Transwell migration and Wound healing assay. The mechanism of cell death and apoptosis was measured by reactive oxygen species (ROS) generation. Fisetin was significant in suppressing CCA cell viability and colony formation during the course of this experiment. Moreover, fisetin significantly potentiated the cisplatin-induced CCA cells death by determination with a combination index (CI). Additionally, it reduced the CCA cells growth through stimulating apoptosis, as seen by a reduction in the viable cell numbers and an increase in apoptotic cells. Fisetin also reduced the migration of cancer cells and demonstrated more pronounced effects on KKU-M452 cells, which are characterized by rapid migration, compared to KKU-100 cells which are characterized by slow migration. Moreover, fisetin prompted cell death and apoptosis in CCA cells by stimulating the generation of ROS in KKU-100 cells at a dosage of 50 μM. According to these results, fisetin efficiently restricts the growth of both CCA cell types by preventing cell proliferation, inducing apoptosis, and stopping migration which are accomplished by producing ROS. Therefore, fisetin could be considered as a promising therapeutic approach for targeting CCA cells.

Dual blockage of PI3K-mTOR and FGFR induced autophagic cell death in cholangiocarcinoma cells

PURPOSE

To assess the impact of concurrent inhibition of the FGFR and PI3K/mTOR signaling pathways on oncogenic characteristics in cholangiocarcinoma (CCA) cells, including proliferation, autophagy, and cell death.

MATERIALS AND METHODS

KKU-213A, KKU-100, and KKU-213C cells were treated with either infigratinib or PKI-402 alone or in combination. Cell viability and cell death were evaluated using the sulforhodamine B (SRB) assay and acridine orange/ethidium bromide (AO/EB) staining. Cell cycle progression and apoptotic cell death were analyzed by flow cytometry. Western blotting was performed to assess the expression of proteins involved in cell cycle regulation and autophagy. Additionally, AO staining was employed to assess autophagic induction.

RESULTS

The combination of infigratinib and PKI-402 showed a remarked synergistic suppression in cell viability in both CCA cell lines compared to treatment with single inhibitors. This antiproliferative effect was associated with cell cycle arrest in the G2-M phase and a decrease in the expression of cyclin A and cyclin B1 in CCA cells. Furthermore, the combination treatment induced apoptotic cell death to a greater extent than treatment with a single inhibitor. Infigratinib enhanced the induction of autophagy by PKI-402, as evidenced by marked increases of autophagic vacuoles stained acridine orange, levels of LC3B-II and suppression of levels of p-mTOR and. Notably, inhibition of autophagic flux by chloroquine prevented cell death induced by the combination treatment.

CONCLUSIONS

This study demonstrated that concurrent inhibition of the key FGFR/PI3K/mTOR pathways in CCA carcinogenesis enhances the suppression of CCA cells. The present findings indicate potential clinical implications for using combination treatment modalities in CCA therapy.

NQO1 expression correlates with cholangiocarcinoma prognosis

Cholangiocarcinoma (CCA) is a rare type of liver cancer with a very poor prognosis. The prevalence of CCA is markedly variable with the highest incidence in the northeast Thailand, followed by other parts of Southeast Asia and China. Currently, there is still no reliable biomarker for diagnosis or treatment. NADPH-quinone oxidoreductase 1 (NQO1) is a xenobiotic metabolizing enzyme detoxifying chemical stressors and antioxidants, thereby providing cytoprotection in normal tissues. However, NQO1 is over-expressed in some cancers, suggesting roles in carcinogenesis and tumor progression. In this study, we examined NQO1 activity in surgical specimens from CCA patients and found much higher values than in the adjacent normal tissues. Immunohistochemical analysis revealed strong staining in tumor epithelial elements, whereas the non-tumor bile ducts and liver parenchyma were weakly stained. NQO1 mRNA expression in tumor tissues was widely varied among 43 patients. A significant association was observed between high level of NQO1 expression and short overall survival time by the Cox proportional hazard ratio of 2.40, p<0.05. By histological classification, non-papillary adenocarcinoma was an independent predictor for poor prognosis with the hazard ratio of 2.79, p<0.05. NQO1 expression may serve as a prognostic biomarker for the CCA.

13‑cis‑retinoic acid inhibits the self‑renewal, migration, invasion and adhesion of cholangiocarcinoma cells

13‑cis‑retinoic acid (13CRA), a Food and Drug Administration‑approved drug for severe acne, is currently being investigated for its potential use in skin cancer prevention. 13CRA has been reported to exhibit antitumor effects against various types of cancer cells, both in vitro and in vivo. However, to the best of our knowledge, no information is yet available regarding the effects of 13CRA on cholangiocarcinoma (CCA), a malignancy of the bile duct epithelia. Currently, there are no reliably effective therapeutic options for metastatic CCA. The present study thus aimed to evaluate the effects of 13CRA on the self‑renewal, migration, invasion and adhesion of CCA cells, and also investigated the underlying mechanisms. The results revealed that 13CRA suppressed cell proliferation via the inhibition of the self‑renewal ability of CCA cells. 13CRA induced cell cycle arrest at the G2/M phase in KKU‑100 and KKU‑213B CCA cells through the regulation of cell cycle‑regulatory genes and proteins. 13CRA reduced the cell migratory ability of both cell lines via the modulation of the genes and proteins associated with epithelial‑mesenchymal transition. 13CRA also inhibited the invasive and adhesive abilities of CCA cells via the suppression of genes and proteins associated with the invasion and adhesion of CCA cells. On the whole, these results suggested that 13CRA exerts suppressive effects on CCA cell proliferation, migration, adhesion and invasion.

IMPAIRED ENDOTHELIAL FUNCTION IN PEDIATRIC HEMOGLOBIN E/β-THALASSEMIA PATIENTS WITH IRON OVERLOAD

Hemoglobin E/β-thalassemia (HbE/β-thalassemia) is the most important type of thalassemia in northeastern Thailand. Serious complications of the disease are associated with iron overload and the consequences of oxidative damage to various organs, especially the cardiovascular system. Endothelial dysfunction is an important predictor for the long-term outcome of the disease. In this study, 19 patients with HbE/β-thalassemia (aged 12.9 ± 2.8 years) and 18 healthy controls (aged 11.8 ± 1.6 years) were enrolled and their oxidant and antioxidant status was determined. Their vascular endothelial function was assessed by ultrasonographic measurement of flow-mediated dilation (FMD) of the brachial artery. The thalassemia patients were found to have higher levels of oxidative stress (based on plasma levels of malondialdehyde and protein carbonyls) and significantly reduced antioxidant levels [based on levels of glutathione (GSH) in whole blood (p < 0.001)]. Thalassemia patients showed endothelial dysfunction as shown by their FMD response during reactive hyperemia (p < 0.001). The degree of impaired FMD response was correlated with the age, hemoglobin levels and serum free iron levels of subjects (p < 0.05). In conclusion, the FMD response was reduced in children with HbE/β-thalassemia and the degree of this reduction was correlated with the severity of anemia. FMD can be used for clinical evaluation of endothelial dysfunction, which could be an independent predictor of the cardiovascular events of thalassemia patients.

Genetic polymorphism of drug metabolizing enzymes in association with risk of bile duct cancer

Cholangiocarcinoma (CCA) is the most common cancer in endemic areas of liver fluke infection. Although the liver fluke is recognized as a carcinogenic agent in cholangiocarcinogenesis, other factors may play important roles in bringing about the high prevalence of the cancer in populations of this region. Drug metabolizing enzymes (DME) are essential for detoxification of toxic and carcinogenic chemicals. Moreover, DME can play an alternative role by activating chemicals to more toxic metabolites. The large variation of DME activity among individuals is partly due to polymorphism of the genes encoding enzymes. Defective or variant alleles of DME genes may modify the risk of cancer in those who are exposeed to carcinogenic agents. The focus in this review is on DME genes which have been reported to be associated with CCA risk. These include CYP1A2, arylamine- N-acetyltransferase-1 (NAT1) and NAT2, NADPH-quinone oxidorecutase-1 (NQO1), glutathione-S-transferase M1 (GSTM1), GSTT1, GSTO1 and methylenetetrahydrofolate reductase (MTHFR). Mutant alleles which have been reportedly associated with an increased risk include CYP1A2*1F, GSTT1 null, GSTO1 and MTHFR 677C>T, whereas, slow NAT2 and NQO1*2 decrease risk and NAT1 variants and GSTM1 null have no effect. These genes modify the risk of cancer potentially by interaction and exposure with certain environmental conditions, thereby altering the metabolism of causative agents.

Drug metabolizing enzyme CYP1A2 status in pediatric patients with hemoglobin E-beta thalassemia

OBJECTIVE

To evaluate the drug metabolizing enzyme CYP1A2 activity in pediatric hemoglobin E-beta-thalassemia patients, since CYP1A2 is responsible for the metabolism of a number of drugs. Alteration of its activity may have clinical consequences.

MATERIAL AND METHOD

Twenty-three hemoglobin E-beta thalassemia pediatric patients and 24 age-matched controls were recruited in the present study. Caffeine in the form of a soft drink was orally administered as a test probe for CYP1A2 activity. Plasma collected at pre-dose and 6 hr after intake was analyzed for the levels of caffeine and paraxanthine, its major metabolite to represent the activity of CYPIA2.

RESULTS

Biochemical markers, including blood glutathione and urinary lipid hydroperoxides indicated that patients were in an oxidant stress state. The plasma ratio of paraxanthine to caffeine was unchanged between patients and controls. Multiple regression analysis revealed that gender and the liver enzyme were the significant determinants of CYP1A2 activity (adjusted r2 = 0.48, p < 0.001). Male gender was associated with higher activity of CYP1A2 activity.

CONCLUSION

The CYP1A2 activity is not apparently changed in thalassemia patients despite the presence of an oxidative stress state.

Inhibition of taurocholate transport by cyclosporin A in cultured rat hepatocytes

Cyclosporin A, a powerful immunosuppressant, has been shown to interfere with the transport of bile salts and other substrates in isolated rat liver cells and to suppress bile flow and bile salt secretion in situ. Cyclosporin A was added to primary hepatocyte cultures just before taurocholate to study the immediate effects on transport. In prolonged exposure experiments cyclosporin A was dissolved in culture media. Efflux was studied by preloading cultured cells with [14C]taurocholate and then changing to sodium-free buffer containing no taurocholate. Cyclosporin A inhibited the uptake and efflux of taurocholate in a competitive manner when added just before determination of transport. Hepatocyte cultures which were pre-exposed to cyclosporin A (1-25 microM) for 18 hr and then washed, also showed a significantly lower taurocholate uptake. The longer the pre-exposure time the greater was the suppression. However, the inhibition could be reversed gradually by incubation of cultured cells in fresh media, complete reversal being attained within 3 hr. These results indicate that cyclosporin A competitively inhibits the taurocholate transport system. The interaction between cyclosporin A and transport components is rapid and long lasting but reversible.