A quantification method of somatic mutations in normal tissues and their accumulation in pediatric patients with chemotherapy.

Somatic mutations are accumulated in normal human tissues with aging and exposure to carcinogens. If we can accurately count any passenger mutations in any single DNA molecule, since their quantity is much larger than driver mutations, we can sensitively detect mutation accumulation in polyclonal normal tissues. Duplex sequencing, which tags both DNA strands in one DNA molecule, enables accurate count of such mutations, but requires a very large number of sequencing reads for each single sample of human-genome size. Here, we reduced the genome size to 1/90 using the BamHI restriction enzyme and established a cost-effective pipeline. The enzymatically cleaved and optimal sequencing (EcoSeq) method was able to count somatic mutations in a single DNA molecule with a sensitivity of as low as 3 × 10-8 per base pair (bp), as assessed by measuring artificially prepared mutations. Taking advantages of EcoSeq, we analyzed normal peripheral blood cells of pediatric sarcoma patients who received chemotherapy (n = 10) and those who did not (n = 10). The former had a mutation frequency of 31.2 ± 13.4 × 10-8 per base pair while the latter had 9.0 ± 4.5 × 10-8 per base pair (P < 0.001). The increase in mutation frequency was confirmed by analysis of the same patients before and after chemotherapy, and increased mutation frequencies persisted 46 to 64 mo after chemotherapy, indicating that the mutation accumulation constitutes a risk of secondary leukemia. EcoSeq has the potential to reveal accumulation of somatic mutations and exposure to environmental factors in any DNA samples and will contribute to cancer risk estimation.

The methylation level of a single cancer risk marker gene reflects methylation burden in gastric mucosa.

BACKGROUND: Gastric cancer risk can be accurately predicted by measuring the methylation level of a single marker gene in gastric mucosa. However, the mechanism is still uncertain. We hypothesized that the methylation level measured reflects methylation alterations in the entire genome (methylation burden), induced by Helicobacter pylori (H. pylori) infection, and thus cancer risk. METHODS: Gastric mucosa of 15 healthy volunteers without H. pylori infection (G1), 98 people with atrophic gastritis (G2), and 133 patients with gastric cancer (G3) after H. pylori eradication were collected. Methylation burden of an individual was obtained by microarray analysis as an inverse of the correlation coefficient between the methylation levels of 265,552 genomic regions in the person's gastric mucosa and those in an entirely healthy mucosa. RESULTS: The methylation burden significantly increased in the order of G1 (n = 4), G2 (n = 18), and G3 (n = 19) and was well correlated with the methylation level of a single marker gene (r = 0.91 for miR124a-3). The average methylation levels of nine driver genes tended to increase according to the risk levels (P = 0.08 between G2 vs G3) and was also correlated with the methylation level of a single marker gene (r = 0.94). Analysis of more samples (14 G1, 97 G2, and 131 G3 samples) yielded significant increases of the average methylation levels between risk groups. CONCLUSIONS: The methylation level of a single marker gene reflects the methylation burden, which includes driver gene methylation, and thus accurately predicts cancer risk.

Risk stratification for gastric cancer after Helicobacter pylori eradication: A population-based study on Matsu Islands.

BACKGROUND AND AIM: The reliable method to stratify the gastric cancer risk after Helicobacter pylori eradication remains an elusive goal. METHODS: Mass eradication of H. pylori began in 2004 in a high-risk population. After eradication, a screening program involving first-stage serological tests (pepsinogen-I, pepsinogen-II, H. pylori immunoglobin G, and gastrin-17) and second-stage endoscopic examination was launched in 2015-2018. Index lesions included gastric cancer or extensive premalignant lesions. We evaluated the performance of the serological tests to "rule in" and "rule out" the risk based on positive and negative likelihood ratios, respectively. The methylation levels of microRNA-124a-3 in the stomach were measured to indicate genetic damage. RESULTS: Among 6512 invited subjects, 3895 (59.6%) participated. Both gastrin-17 and pepsinogen tests were normal in 3560 (91.4%) subjects; 206 (5.3%) gastrin-17 and 129 (3.3%) pepsinogen tests were abnormal. Years after eradication, the severity of gastritis had fallen greatly, and extensive premalignant lesions or gastric cancer frequently occurred in newly non-atrophic-appearing mucosa. Pepsinogen testing could moderately predict atrophic gastritis (positive likelihood ratio: 4.11 [95% confidence interval: 2.92-5.77]; negative likelihood ratio: 0.14 [0.10-0.19]). Gastrin-17 was not useful (0.66 and 1.20, respectively). However, pepsinogen testing poorly predicted the index lesions (2.04 [1.21-3.42] and 0.57 [0.34-0.95]). DNA methylation levels in the post-eradication mucosa were more discriminative for predicting index lesions (3.89 [2.32-6.54] and 0.25 [0.15-0.42]). CONCLUSIONS: After eradication, pepsinogen false-negative results become more frequent because histology is improved but genetic damage may persist. Direct testing for genetic damage offers better discrimination.

Evaluation of the relationship between linezolid exposure and hyponatremia.

INTRODUCTION: Aims of this study were (a) to assess the development ratio of hyponatremia during treatment with linezolid and (b) to evaluate the relationship between the risk of hyponatremia and linezolid exposure and patient background. METHOD: Clinical data including linezolid serum concentrations and serum sodium values were collected at Toyama University Hospital and Kyorin University Hospital. Data from 89 patients were used for the analysis, and a nadir serum sodium level ≤130 mmol/L during the treatment with linezolid was defined as hyponatremia. Mann-Whitney's U test was used to evaluate the effects of the area under the time-concentration curve (AUC) of linezolid at the nadir sodium level, clinical characteristics (e.g. laboratory data), and baseline serum sodium levels on the development of hyponatremia. RESULTS: The hyponatremia was occurred in 21 of 89 patients (23.6%). Data are compared for baseline and nadir serum sodium levels of patients with and without hyponatremia. In both groups, nadir serum sodium levels were significantly different from those of the baseline values (P < 0.05). The values of AUC0-12, accumulated AUC, baseline serum sodium levels and age were significantly different between patients with and without hyponatremia (P < 0.05). CONCLUSIONS: Linezolid exposure, age, and baseline sodium levels were detected as the risk factors for linezolid-related hyponatremia. Our findings suggest that regular monitoring of serum sodium levels is desirable during treatment with linezolid, especially for the elderly and patients with low serum sodium levels before the start of linezolid administration.

Effect of CYP3A5*3 genetic variant on the metabolism of direct-acting antivirals in vitro: a different effect on asunaprevir versus daclatasvir and beclabuvir.

Direct-acting antivirals, asunaprevir (ASV), daclatasvir (DCV), and beclabuvir (BCV) are known to be mainly metabolized by CYP3A enzymes; however, the differences in the detailed metabolic activities of CYP3A4 and CYP3A5 on these drugs are not well clarified. The aim of the present study was to elucidate the relative contributions of CYP3A4 and CYP3A5 to the metabolism of ASV, DCV, and BCV, as well as the effect of CYP3A5*3 genetic variant in vitro. The amount of each drug and their major metabolites were determined using LC-MS/MS. Recombinant CYP3As and CYP3A5*3-genotyped human liver microsomes (CYP3A5 expressers or non-expressers) were used for the determination of their metabolic activities. The contribution of CYP3A5 to ASV metabolism was considerable compared to that of CYP3A4. Consistently, ASV metabolic activity in CYP3A5 expressers was higher than those in CYP3A5 non-expresser. Moreover, CYP3A5 expression level was significantly correlated with ASV metabolism. In contrast, these observations were not found in DCV and BCV metabolism. To our knowledge, this is the first study to directly demonstrate the effect of CYP3A5*3 genetic variants on the metabolism of ASV. The findings of the present study may provide basic information on ASV, DCV, and BCV metabolisms.

Minor contribution of CYP3A5 to the metabolism of hepatitis C protease inhibitor paritaprevir in vitro.

Paritaprevir (PTV) is a non-structural protein 3/4A protease inhibitor developed for the treatment of hepatitis C disease as a fixed dose combination of ombitasvir (OBV) and ritonavir (RTV) with or without dasabuvir. The aim of this study was to evaluate the effects of cytochrome P450 (CYP) 3A5 on in vitro PTV metabolism using human recombinant CYP3A4, CYP3A5 (rCYP3A4, rCYP3A5) and human liver microsomes (HLMs) genotyped as either CYP3A5*1/*1, CYP3A5*1/*3 or CYP3A5*3/*3. The intrinsic clearance (CLint, Vmax/Km) for the production of a metabolite from PTV in rCYP3A4 was 1.5 times higher than that in rCYP3A5. The PTV metabolism in CYP3A5*1/*1 and CYP3A5*1/*3 HLMs expressing CYP3A5 was comparable to that in CYP3A5*3/*3 HLMs, which lack CYP3A5. CYP3A4 expression level was significantly correlated with PTV disappearance rate and metabolite formation. In contrast, there was no such correlation found for CYP3A5 expression level. This study represents that the major CYP isoform involved in PTV metabolism is CYP3A4, with CYP3A5 having a minor role in PTV metabolism. The findings of the present study may provide foundational information on PTV metabolism, and may further support dosing practices in HCV-infected patients prescribed PTV-based therapy.

Novel epigenetic markers for gastric cancer risk stratification in individuals after Helicobacter pylori eradication.

BACKGROUND: The risk stratification of healthy individuals after Helicobacter pylori eradication is an urgent issue. The assessment of aberrant DNA methylation accumulated in gastric tissues with normal appearance, which can reflect overall epigenomic damage, is a promising strategy. We aimed to establish novel epigenetic cancer risk markers for H. pylori-eradicated individuals. METHODS: Gastric mucosa was collected from eight healthy volunteers without H. pylori infection (G1), 75 healthy individuals with gastric atrophy (G2), and 94 gastric cancer patients (G3) after H. pylori eradication. Genome-wide analysis was conducted using Infinium 450 K and differentially methylated probes were screened using large difference and iEVORA-based methods. Bisulfite pyrosequencing was used for validation. RESULTS: Screening, using 8 G1, 12 G2, and 12 G3 samples, isolated 57 candidates unmethylated in G1 and differentially methylated in G3 compared with G2. Validation for nine candidate markers (FLT3, LINC00643, RPRM, JAM2, ELMO1, BHLHE22, RIMS1, GUSBP5, and ZNF3) in 63 G2 and 82 G3 samples showed that all of them had significantly higher methylation levels in G3 than in G2 (P < 0.0001). Their methylation levels were highly correlated, which indicated that they reflect overall epigenomic damage. The candidates had sufficient performance (AUC: 0.70-0. 80) and high odds ratios (5.43-23.41), some of which were superior to a previous marker, miR-124a-3. The methylation levels of our novel markers were not associated with gastric atrophy, gender, or age. CONCLUSIONS: Novel epigenetic markers for gastric cancer risk optimized for H. pylori-eradicated individuals were established.

Linezolid-Induced Thrombocytopenia Is Caused by Suppression of Platelet Production via Phosphorylation of Myosin Light Chain 2.

Linezolid (LZD) is an antimicrobial that is commonly used for treatment of vancomycin-resistant Enterococci and methicillin-resistant Staphylococcus aureus infections. However, the development of thrombocytopenia, one of the most frequent adverse side effects of this antimicrobial, can lead to discontinuation of LZD treatment. While clinical studies indicate that risk factors for the development of LZD-induced thrombocytopenia include treatment for >14 consecutive days, renal dysfunction, and chronic liver disease, the fundamental mechanism governing the pathogenesis of this disorder remains unclear. In this study, we aimed to elucidate the mechanism of LZD-induced thrombocytopenia by investigating the impact of LZD treatment on platelet destruction and production using rat platelet-rich plasma (PRP) and human immortalized cell lines, respectively. Compared to the control population, an increase in lactate dehydrogenase release was not detected upon exposure of rat PRP to varying concentrations of LZD, indicating that this compound is not cytotoxic towards platelets. Meanwhile, LZD treatment resulted in a significant dose-dependent increase in the proliferation of HEL human erythroleukemia and MEG-01 human megakaryoblast cells in vitro, but did not influence the differentiation of these cell lines. Lastly, LZD treatment yielded elevated levels of phosphorylation of myosin light chain 2 (MLC2), which regulates platelet release, in MEG-01 cells. Based on these results, we speculate that LZD induces thrombocytopenia by promoting MLC2 phosphorylation and thereby suppressing the release of platelets from mature megakaryocytes. These findings provide the first insight into the mechanism of LZD-mediated thrombocytopenia and may facilitate the development of strategies to treat and/or prevent this disease.

Gosha-jinki-gan reduced oxaliplatin-induced hypersensitivity to cold sensation and its effect would be related to suppression of the expression of TRPM8 and TRPA1 in rats.

Peripheral neuropathy is a common side effect of the chemotherapeutic agent oxaliplatin (Oxp), and is associated with hypersensitivity to cold sensation in the acute stage. Recently, gosha-jinki-gan (GJG), a Japanese herbal medicine, was reported to improve Oxp-induced cold hypersensitivity. However, the mechanism for this effect was not elucidated. We hypothesized that the effect of GJG on Oxp-induced cold hypersensitivity may be associated with the expression of the transient receptor potential melastatin 8 (TRPM8) and transient receptor potential ankyrin 1 (TRPA1) channels, which are cold-gated ion channels. To assess this hypothesis, we examined alteration of the withdrawal response to cold stimulation following coadministration of GJG and Oxp in rats, and the relationship between this altered withdrawal response and the expression of TRPM8 and TRPA1 mRNA in the dorsal root ganglia (DRG). Assessment of cold hypersensitivity was performed at 4 and 10°C using a cold plate. Compared with Oxp administration alone, coadministration of GJG (oral dose: 1 g/kg/day for 12 days) and Oxp (intraperitoneal dose: 4 mg/kg twice a week) significantly reduced the withdrawal response to cold stimulation. On the 12th day of drug administration, the L4-L6 DRG were removed and the expression of TRPM8 and TRPA1 mRNA was determined using RT-PCR. The expression of TRPM8 and TRPA1 in the DRG of rats that were coadministered GJG and Oxp decreased significantly compared with that in the rats administered Oxp alone. These results suggest that coadministration of GJG may improve Oxp-induced cold hypersensitivity by suppressing the overexpression of TRPM8 and TRPA1 mRNA.

Enantioselective disposition of clenbuterol in rats.

Clenbuterol is a long-acting ß2-adrenoceptor agonist and bronchodilator that is used for the treatment of asthma, but the desired activities reside almost exclusively in the (-)-R-enantiomer. This study examined enantioselectivity in the disposition of clenbuterol following administration of clenbuterol racemate to rats. Concentrations of clenbuterol enantiomers in plasma, urine and bile were determined by LC-MS/MS assay with a Chirobiotic T column. This method was confirmed to show high sensitivity, specificity and precision, and clenbuterol enantiomers in 0.1 ml volumes of plasma were precisely quantified at concentrations as low as 0.25 ng/ml. The pharmacokinetic profiles of clenbuterol enantiomers following intravenous and intraduodenal administration of clenbuterol racemate (2 mg/kg) in rats were significantly different. The distribution volume of (-)-R-clenbuterol (9.17 l/kg) was significantly higher than that of (+)-S-clenbuterol (4.14 l/kg). The total body clearance of (-)-R-clenbuterol (13.5 ml/min/kg) was significantly higher than that of the (+)-S-enantiomer (11.5 ml/min/kg). An in situ absorption study in jejunal loops showed no difference in the residual amount between the (-)-R- and (+)-S-enantiomers. Urinary clearance was the same for the two enantiomers, but biliary excretion of (-)-R-clenbuterol was higher than that of the (+)-S-enantiomer. The fractions of free (non-protein-bound) (-)-R- and (+)-S-clenbuterol in rat plasma were 48.8% and 33.1%, respectively. These results indicated that there are differences in the distribution and excretion of the clenbuterol enantiomers, and these may be predominantly due to enantioselective protein binding.

Consumption of a high-fat diet during pregnancy changes the expression of cytochrome P450 in the livers of infant male mice.

It has been recently reported that the consumption of a high-fat diet during pregnancy exerts various effects on fetuses and newborn mice. The purpose of this study was to determine the effects of a high-fat diet during pregnancy on the expression of cytochrome P450 (CYP) in the livers of offspring. Mouse dams were fed a high-fat diet during pregnancy from the time of conception. After their birth, the newborn mice were fed a normal diet until 12 weeks of age. In the livers of the infant male mice that consumed a high-fat diet, the protein expression of CYP3A and CYP2C was decreased, and the protein expression of CYP1A and CYP2E was increased at 6 and 12 weeks of age. However, almost no changes were observed in the CYP proteins at 6 and 12 weeks of age in the livers of the infant female mice that consumed a high-fat diet. The amount of pregnane X receptor (PXR) translocated into the nucleus was reduced in the livers of infant male mice that consumed a high-fat diet. However, there was neither an increase in tumor necrosis factor-α or interleukin-1ß nor a decrease in lithocholic acid. These data suggested that CYP3A and CYP2C might decrease as a result of the decrease in the amount of nuclear PXR in infant male mice that consumed a high-fat diet. The results of this study suggested that the consumption of a high-fat diet by pregnant mothers may be one explanation for individual differences in pharmacokinetics.

Different diets cause alterations in the enteric environment and trigger changes in the expression of hepatic cytochrome P450 3A, a drug-metabolizing enzyme.

Changes in the expression level and activity of cytochrome P450 (CYP) in the liver are caused by various factors and affect the pharmacokinetics of drugs. The purpose of this study was to determine whether the expression of CYP3A is affected by a high-fat diet. In addition, we examined whether the type of diet given to mice could produce changes in the expression level and activity of CYP3A. Mice were fed a purified diet containing 10 kcal% lard (control group) or 60 kcal% lard (HF group) or regular mouse chow containing 13 kcal% of fat (MF group) for 4 weeks. No significant differences were observed in the hepatic CYP3A protein expression level between the HF group and the control group. The CYP3A protein expression in the MF group was significantly higher than that observed in the control group. In the MF group, the area under the curve (AUC) of intraperitoneally administered triazolam was lower. Because lithocholic acid (LCA) is known to increase hepatic CYP3A expression, the levels of Clostridium sordellii and LCA in the feces were measured. In the MF group, the levels of Clostridium sordellii and LCA were higher. It has been demonstrated that a high-fat diet does not cause any changes in hepatic CYP3A expression. In addition, the different diets caused alterations in the enteric environment, which triggered changes in CYP3A expression. Therefore, it is necessary to carefully consider the type of feed while performing animal experiments to evaluate the pharmacokinetics of drugs.

[A patient with primary breast cancer who responded remarkably well to neoadjuvant chemotherapy with FEC100 followed by Abraxane].

A 49-year-old woman visited our hospital presentind with a right breast lump. She underwent core needle biopsy, and her disease was diagnosed as breast cancer(invasive ductal carcinoma, ER slightly positive, PgR and HER2 negative). We chose neoadjuvant chemotherapy because the tumor size was over 3 cm in diameter with a histological grade III, and she asked to have her breast conserved. Because she had an allergy to alcohol, we treated her with FEC100 followed by Abraxane(260mg/ m2)q3W for 4 courses. After chemotherapy, she received breast conserving therapy. During the treatment with Abraxane, the patient was very well and showed no major side effects except for grade 3 neutropenia was found on an outpatient basis. After chemotherapy, breast MRI detected no invasive lesion. Pathological examination showed pCR. We concluded that Abraxane was a good option as neoadjuvant chemotherapy for early breast cancer.

ARID1A loss-of-function induces CpG island methylator phenotype.

The CpG island methylator phenotype (CIMP) is associated with prognosis and drug sensitivity in multiple cancer types. In gastric cancer, the CIMP is closely associated with Epstein-Barr virus (EBV) infection and AT-rich interactive domain 1A (ARID1A) mutations, a component of the SWI/SNF chromatin remodeling complex. However, the involvement of SWI/SNF defects in CIMP induction has been unclear. In this study, we demonstrate a causal role of ARID1A loss-of-function in CIMP induction. Mutations of SWI/SNF components, especially ARID1A, was associated with the CIMP, as well as EBV infection, in gastric cancers, and also in uterine endometrial and colorectal cancers, which are not affected by EBV infection. Genome-wide DNA methylation analysis showed that ARID1A knockout (KO) in cultured 293FT cells and gastric epithelial cells, GES1, induced aberrant DNA methylation of a substantial number of CpG sites. DNA methylation was induced at genomic regions with high levels of pre-existing histone H3 lysine 27 trimethylation (H3K27me3) and those with acquired H3K27me3 by ARID1A KO. These results showed that the ARID1A mutation induced aberrant DNA methylation, and this is likely to be one of the potential mechanisms of CIMP induction.

Effects of anti-malarial drugs on the electrocardiographic QT interval modelled in the isolated perfused guinea pig heart system.

BACKGROUND: Concern over the potential cardiotoxicity of anti-malarial drugs inducing a prolonged electrocardiographic QT interval has resulted in the almost complete withdrawal from the market of one anti-malarial drug - halofantrine. The effects on the QT interval of four anti-malarial drugs were examined, using the guinea pig heart. METHODS: The guinea pig heart was isolated, mounted on a Langendorff apparatus, and was then perfused with pyruvate-added Klebs-Henseleit solutions containing graded concentrations of the four agents such as quinidine (0.15 - 1.2 µM), quinine (0.3 - 2.4 µM), halofantrine (0.1 - 2.0 µM) and mefloquine (0.1 - 2.0 µM). The heart rate-corrected QaTc intervals were measured to evaluate drug-induced QT prolongation effects. RESULTS: Quinidine, quinine, and halofantrine prolonged the QaTc interval in a dose-dependent manner, whereas no such effect was found with mefloquine. The EC50 values for the QaTc prolongation effects, the concentration that gives a half-maximum effect, were quinidine < quinine ≈ halofantrine. CONCLUSIONS: In this study, an isolated, perfused guinea pig heart system was constructed to assess the cardiotoxic potential of anti-malarial drugs. This isolated perfused guinea pig heart system could be used to test newly developed anti-malarial drugs for their inherent QT lengthening potential. More information is required on the potential variation in unbound drug concentrations in humans, and their role in cardiotoxicity.

The removal of estrogenic activity and control of brominated by-products during ozonation of secondary effluents.

The purposes of this study were to investigate the behavior of brominated by-products, such as bromate ion and total organic bromide, formed during ozonation for the removal of estrogenic activity in sewage effluents and to propose operation parameters for the ozonation process. It is necessary to reduce the E(2) equivalent concentration of estrogenic activity in secondary effluent treated by 90% of the initial one. To do so, ozonation until dissolved ozone concentration increased to 0.1mg/L (which corresponds to approximately 1mg O(3)/mg DOC(0) [consumed ozone per initial DOC] of consumed ozone for the effluent in this study) is proposed as an operation parameter for ozonation without the formation of brominated by-products.

Removal of endocrine-disrupting chemicals by ozonation in sewage treatment.

Treatment experiments by two laboratory scale semi-batch reactors and a demonstration scale process were both carried out to evaluate endocrine disrupting chemical removal characteristics by ozonation in sewage treatment. In the semi-batch mode experiments, secondary effluent and primary effluen of sewage treatment plants were ozonated respectively. Behaviour of brominated by-products was also evaluated. The results based on these studies indicated that estrogenicity in wastewater can be removed by ozonation effectively. The condition of ozonation until dissolved ozone concentration increased to 0.1 mg/L, which corresponded to 1 mgO3/mgC and 0.4 mgO3/mgC of ozone consumption per initial DOC for secondary effluent and primary effluent, respectively, is proposed as an appropriate operational condition for efficient removal of EDCs as well as UV254 and SUVA without production of brominated by-products.

Organic anion transporting polypeptide 2B1 expression correlates with uptake of estrone-3-sulfate and cell proliferation in estrogen receptor-positive breast cancer cells.

Estrone-3-sulfate (E1S) is thought to be a major estrogen precursor in estrogen receptor (ER)-positive breast cancer. Since E1S is a hydrophilic compound, the uptake of E1S into cancer cells is probably mediated by transporters, such as organic anion-transporting polypeptide (OATP, SLCO) family. In this study, we investigated the relationship between expression of OATP2B1 and cell proliferation in ER-positive breast cancer. Cell-based assays were carried out in MCF-7 cells both with and without overexpression of OATP2B1. Normal breast and tumor tissues were collected and used in this study. Cell proliferation, ER-mediated transcriptional activities and estradiol secretion were stimulated by addition of E1S to the culture medium of MCF-7 cells. These stimulatory effects were significantly greater in MCF-7 cells overexpressing OATP2B1 than in control cells. The expression level of SLCO2B1 mRNA was significantly correlated with histological grade, Ki-67 labelling index and mRNA expression of steroid sulfatase. The expression level of SLCO2B1 mRNA in luminal B-like cancers was higher than that in luminal A-like cancers. Uptake of E1S resulted in down-regulation of ERα protein and induction of Ki-67 in MCF-7 cells. The present study suggests that OATP2B1 is involved in cell proliferation by increasing the amount of estrogen in ER-positive breast cancer cells.

Influence of single-nucleotide polymorphisms in the multidrug resistance-1 gene on the cellular export of nelfinavir and its clinical implication for highly active antiretroviral therapy.

Protease inhibitors (PIs) such as nelfinavir (NFV) suppress HIV replication. PIs are substrates of P-glycoprotein (P-gp), the product of the multidrug-resistance-1 (MDR1) gene. Three single-nucleotide polymorphisms (SNPs) are present in exons of the MDR1 gene: MDR1 1236, MDR1 2677 and MDR1 3435. We speculated that these genetic polymorphisms affected PI concentration in the cell. To verify this hypothesis, we first genotyped these SNPs in 79 Japanese patients by the SNaPshot method and found incomplete linkage disequilibrium between the SNPs. Because the SNP at MDR1 3435 has been reported to be associated with P-gp expression, we evaluated the effect of that SNP on the export of NFV from HIV-positive patients' lymphoblastoid cell lines by measuring time-dependent decrease in the amount of intracellular NFV by high-performance liquid chromatography. We found the intracellular concentration of NFV in lymphoblastoid cell lines (LCLs) with the homozygous T/T genotype at MDR1 3435 were higher than that with C/C genotype with statistical significance. This suggests that the activity of P-gp in patients' LCL cells with the MDR1 3435 T/T genotype was lower. In a retrospective study we evaluated the effect of the SNPs on CD4 cell count recovery in response to antiretroviral treatment with PIs, and obtained statistically significant evidence that suggested marginal association of the SNP at MDR1 1236 but not at MDR1 2677 or MDR1 3435. As in vitro results were not consistent with the clinical evaluation, clinical importance of MDR1 genotyping for antiretroviral therapy remains to be investigated in a larger, case-controlled study.

Recommendations for the treatment of fungal pneumonias.

Incidences of fungal pneumonias have increased in immunocompromised patients with HIV infection or receiving bone marrow replacement or solid organ transplantation. Fungal pneumonias including aspergillosis, cryptococcosis, candidiasis, coccidioidomycosis, histoplasmosis and blastomycosis are one of the major causes of morbidity and mortality among the immunosuppressed hosts. Therefore, clinicians should consider the most appropriate and aggressive treatment of fungal pneumonias in this population. This report outlines the state of the art in the treatment of fungal pneumonias and discusses recent advances in antifungal therapy. Practice guidelines for the treatment with commonly used antifungal agents including amphotericin B, fluconazole, itraconazole, ketoconazole and flucytosine, are very useful for clinicians to manage the diseases appropriately. Echinocandins and second-generation triazoles will hopefully help clinicians to overcome the limitations of the current therapy.