These findings indicate that albumin in alveolar lining fluid is internalized into type II and type I epithelial cells via clathrin-mediated endocytosis, and the rate of albumin uptake is higher in type II cells than type I cells.

We investigated the effects of epigenetic modifiers such as DNA methyltransferase (DNMT) or histone deacetylase (HDAC) inhibitors on the cytotoxicity induced by 3 anticancer drugs (5-fluorouracil (5-FU), irinotecan (CPT-11) or its active form SN38, and oxaliplatin (L-OHP)) in human colorectal cancer (CRC) cells. Cytotoxicity in 4 CRC cell lines (HT29, SW480, SW48 and HCT116) was examined by colorimetric assay after drug treatment for 72 h. The effects of drug combinations were analyzed by an isobologram method. SW480 cells showed the lowest sensitivity to cytotoxicity induced by the anticancer drugs among the 4 CRC cell lines. In SW480 cells, DNMT inhibitors, such as decitabine (DAC), azacytidine and zebularine (Zeb), showed synergic effects on the cytotoxicity induced by anticancer drugs except for SN-38 plus Zeb, while HDAC inhibitors, trichostatin A, suberoylanilide hydroxamic acid and valproic acid, showed antagonistic effects. DAC showed the most potent synergic effects among the epigenetic modifiers studied. Thus, we examined whether the synergic effect of DAC is observed in other different CRC cell lines, HT29, SW48 and HCT116 cells. In all 4 CRC cell lines, the cytotoxicity of L-OHP was enhanced in a synergic manner by cotreatment with DAC. However, synergic effects of DAC with 5-FU or CPT-11 (SN-38) were not observed in 4 CRC cell lines.Key words DNA methyltransferase inhibitor; synergism; colorectal cancer; isobologram; histone deacetylase inhibitor Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the world.1) CRC treatment strategies are highly dependent on tumor stage. Metastatic CRC (stage IV) is treated with combined chemotherapy, including 5-fluorouracil (5-FU) plus either irinotecan (CPT-11) or oxaliplatin (L-OHP). Recently, it has been reported that combined chemotherapy plus biological agents (anti-angiogenic or antiepidermal growth factor receptor molecules) increased stage IV patients' median survival period.2) Despite many therapeutic options, an efficient drug combination remains to be found for CRC patients. In addition, tailored therapy for each CRC patient is still a challenge.It is well-established that epigenetic alterations such as DNA methylation and histone modifications play a crucial role in the initiation and progression of cancer, including CRC. Unlike genetic alterations, epigenetic alterations are reversible and can be targeted by epigenetic modifiers.3) Epigenetic modifiers such as DNA methyltransferase (DNMT) inhibitors and histone deacetylase (HDAC) inhibitors have been administered for several years and have been evaluated as a treatment approach for a variety of cancers in the United States. DNMT inhibitors, such as decitabine (5-aza-2′-deoxycytidine; DAC) and 5-azacytidine (AC), are being used for the treatment of myelodysplastic syndromes (MDS), but the efficacy is variable. 4,5) In addition, DAC is used usually for patients with acute myeloid leukemia who are not candidates for standard remission, including chemotherapy. 6) On the other h...

The purpose of this study on the involvement of epigenetic control of the expression of solute carrier (SLC) transporters by DNA methylation and histone deacetylation in 4 colon cancer cells is to find the epigenetic control mechanisms of drug transporters in colon cancers. Human colon cancer cell lines (HCT116, HT29, SW48, SW480) were treated with 5-aza-2′-deoxycytidine (DAC), as a DNA methyltransferase inhibitor, followed by trichostatin A (TSA), as a histone deacetylase inhibitor. The mRNA expression and DNA methylation of several SLC transporters were analyzed by real-time polymerase chain reaction (PCR) and methylation-specific PCR, respectively. Among 12 SLC transporters possessing cytosine-phosphate-guanine (CpG) islands, thiamine transporter 2 (THTR2) (SLC19A3) gene showed a correlation between its mRNA expression level and DNA methylation status. TSA treatment increased histone H3 acetylation of THTR2 promoter region in all 4 colon cancer cell lines examined. HCT116 and SW48 cells showed a lack of THTR2 mRNA expression and methylation of its promoter, and DAC treatment induced its re-expression. In addition, the co-treatment with DAC and TSA increased THTR2 mRNA expression more markedly than DAC treatment in HCT116 and SW48 cells. In HT29 and SW480 cells that showed little methylation of THTR2 promoter, TSA treatment induced THTR2 mRNA expression markedly, but DAC treatment did not. In the 4 colon cancer cells examined, THTR2 mRNA expression is down-regulated by DNA methylation and/or histone deacetylation.Key words solute-carrier transporter; DNA methylation; histone deacetylation; colon cancer; epigenetics; cytosine-phosphate-guanine island Epigenetics refers to heritable changes in gene expression that are not coded in the DNA sequence itself. Epigenetic events include methylation of DNA and modifications to histone proteins. The disruption of epigenetic mechanisms such as DNA methylation and histone acetylation can lead to inappropriate expression or silencing of genes, resulting in several major diseases including cancer. In tumors in particular, DNA hypermethylation in cytosine-phosphate-guanine (CpG) islands in the promoter region of a specific gene is often observed. This phenomenon leads to transcriptional downregulation of cancer-related genes like tumor suppressor genes.

The alveolar epithelium is comprised of type II and type I cells, which are two morphologically and functionally different epithelial cells. Alveolar type I cells, which are squamous and cover more than 90% of the alveolar surface area, play a major role in gas exchange. 1,2) On the other hand, alveolar type II cells are cuboidal and outnumber type I cells, although type II cells occupy less than 10% of the surface area even when their apical microvilli are taken into consideration.1,2) In addition, type II cells have multiple functions such as surfactant production and secretion, and serve as type I cell progenitors.2)The majority of protein and peptide therapeutic drugs were developed as injection formulations, and have a variety of problems, especially for patients, in terms of safety, pain, and needle phobia. 3,4) Recently, the lung has attracted a great deal of interest as an alternative administration route for protein and peptide drugs. 3,5) The inhalation pulmonary delivery system, which may enable the systemic absorption of protein and peptide drugs, has been extensively studied.6) In particular, clinical research on inhaled insulin has confirmed the efficacy and safety of inhaled insulin in the treatment of diabetes mellitus. 7) In addition, the bioavailability of inhaled insulin via the lung is greater compared to other non-invasive routes such as the gut and nose. 8)Previous studies concerning protein transport across alveolar epithelia have suggested that the transport system most likely to be involved is endocytosis. 9) We also have studied the transport of albumin in alveolar epithelial cells, and found that albumin is internalized into type II and type I cells via a clathrin-mediated endocytic pathway with greater uptake activity in type II cells than in type I cells.10) These findings indicate that despite the much smaller surface area of type II cells compared to type I cells, type II cells most likely play an important role in the endocytic transport of proteins in alveolar epithelia.In the case of small proteins (peptides) such as insulin, both paracellular and transcellular routes may be involved in alveolar epithelial transport.1) Bur et al. 11) reported that in human primary cultured alveolar type I-like epithelial cells, the apparent permeability coefficient of insulin was comparable to that reported for dextran, indicating that a specific, transcellular transport process is not involved. On the other hand, the alveolar epithelial junction was reported to be tighter than other epithelia, 1) suggesting that the contribution of a paracellular route for insulin in alveolar epithelial transport may not be so high. Furthermore, it has been reported that megalin serves as an endocytic receptor for insulin uptake in rat renal proximal tubule cells, 12) and that megalin is also expressed in alveolar epithelial cells.13) Thus, it is possible that an endocytic pathway is involved in insulin transport in alveolar epithelia. However, little information is available concerning the handling of insu...

The effects of turmeric extracts on the pharmacokinetics of nifedipine were examined in 10 healthy volunteers. An open-label and randomized crossover study was performed at 2-week intervals. In the control experiment, after a 10 h overnight fast, 10 mg of nifedipine (Adalat® capsule) was administered orally and blood was collected at 0, 0.5, 1, 2, 3, 4, 5, 6, and 8 h. In the combination experiment, the volunteers were orally administered 10 mg of nifedipine together with six tablets containing concentrated turmeric extract (480 mg of curcuminoid per six tablets), which is the general daily dose, and blood was sampled as above. The time profile of the plasma concentration of nifedipine in the control was comparable to that in combination with turmeric extract, as were the pharmacokinetic parameters: that is, the mean ratio of turmeric extract/control group (90% confidence interval: CI); C(max), 0.98 (0.95, 1.01) and AUC(0 - ∞) 1.00 (0.98, 1.02). In addition, the volunteers all completed the study without any serious adverse events. Consumption of the turmeric extract did not affect the pharmacokinetics of nifedipine after a single oral administration.

Sairei-to is a traditional herbal medicine used to complement, and as an alternative to, Western drugs. The aim of this study was to evaluate the pharmacokinetic interactions between Sairei-to and nifedipine (NFP), a substrate for CYP3A, in rats. NFP-oxidizing activity and the pharmacokinetics of NFP were examined after a single or 1-week of administration of Sairei-to (EK-114). NFP-oxidizing activity was enhanced transiently around 24 h after a single administration of EK-114 (1400 mg/kg). In vivo, the first-pass metabolism of NFP increased in the small intestine at 24 h after the administration of EK-114, and this effect disappeared at 72 h. Co-administration of EK-114 tended to inhibit the metabolism of NFP. On the other hand, when EK-114 was given at a high dose (1400 mg/kg) for 1 week, the oxidation of NFP in the small intestine was inhibited, and C max and AUC after the oral administration of NFP increased. In addition, a clinical dose of EK-114 (140 mg/ kg) did not alter the pharmacokinetics of NFP, regardless of the administration schedule. EK-114 was suggested to affect the metabolism of NFP. However, the CYP3A-mediated pharmacokinetic interaction on the concomitant use of EK-114 may not be clinically significant.

No abstract