Kegg Pathway: ABC transporters - General

Br J Pharmacol. 2009 Oct; 158(4): 1153-64
Hegedus C, Ozvegy-Laczka C, Apáti A, Magócsi M, Német K, Orfi L, Kéri G, Katona M, Takáts Z, Váradi A, Szakács G, Sarkadi B

BACKGROUND AND PURPOSE: ABC multidrug transporters (MDR-ABC proteins) cause multiple drug resistance in cancer and may be involved in the decreased anti-cancer efficiency and modified pharmacological properties of novel specifically targeted agents. It has been documented that ABCB1 and ABCG2 interact with several first-generation, small-molecule, tyrosine kinase inhibitors (TKIs), including the Bcr-Abl fusion kinase inhibitor imatinib, used for the treatment of chronic myeloid leukaemia. Here, we have investigated the specific interaction of these transporters with nilotinib, dasatinib and bosutinib, three clinically used, second-generation inhibitors of the Bcr-Abl tyrosine kinase activity. EXPERIMENTAL APPROACH: MDR-ABC transporter function was screened in both membrane- and cell-based (K562 cells) systems. Cytotoxicity measurements in Bcr-Abl-positive model cells were coupled with direct determination of intracellular TKI concentrations by high-pressure liquid chromatography-mass spectrometry and analysis of the pattern of Bcr-Abl phosphorylation. Transporter function in membranes was assessed by ATPase activity. KEY RESULTS: Nilotinib and dasatinib were high-affinity substrates of ABCG2, and this protein mediated an effective resistance in cancer cells against these compounds. Nilotinib and dasatinib also interacted with ABCB1, but this transporter provided resistance only against dasatinib. Neither ABCB1 nor ABCG2 induced resistance to bosutinib. At relatively higher concentrations, however, each TKI inhibited both transporters. CONCLUSIONS AND IMPLICATIONS: A combination of in vitro assays may provide valuable preclinical information for the applicability of novel targeted anti-cancer TKIs, even in multidrug-resistant cancer. The pattern of MDR-ABC transporter-TKI interactions may also help to understand the General pharmacokinetics and toxicities of new TKIs.

BMC Genomics. 2009; 10: 429
Pietiäinen M, François P, Hyyryläinen HL, Tangomo M, Sass V, Sahl HG, Schrenzel J, Kontinen VP

BACKGROUND: Understanding how pathogens respond to antimicrobial peptides, and how this compares to currently available antibiotics, is crucial for optimizing antimicrobial therapy. Staphylococcus aureus has several known resistance mechanisms against human cationic antimicrobial peptides (CAMPs). Gene expression changes in S. aureus strain Newman exposed to linear CAMPs were analyzed by DNA microarray. Three antimicrobial peptides were used in the analysis, two are derived from frog, temporin L and dermaseptin K4-S4(1-16), and the ovispirin-1 is obtained from sheep. RESULTS: The peptides induced the VraSR cell-wall regulon and several other genes that are also up-regulated in cells treated with vancomycin and other cell wall-active antibiotics. In addition to this similarity, three genes/operons were particularly strongly induced by the peptides: vraDE, SA0205 and SAS016, encoding an ABC transporter, a putative membrane-bound lysostaphin-like peptidase and a small functionally unknown protein, respectively. Ovispirin-1 and dermaseptin K4-S4(1-16), which disrupt lipid bilayers by the carpet mechanism, appeared to be strong inducers of the vraDE operon. We show that high level induction by ovispirin-1 is dependent on the amide modification of the peptide C-terminus. This suggests that the amide group has a crucial role in the activation of the Aps (GraRS) sensory system, the regulator of vraDE. In contrast, temporin L, which disrupts lipid bilayers by forming pores, revealed a weaker inducer of vraDE despite the C-terminal amide modification. Sensitivity testing with CAMPs and other antimicrobials suggested that VraDE is a transporter dedicated to resist bacitracin. We also showed that SA0205 belongs to the VraSR regulon. Furthermore, VraSR was shown to be important for resistance against a wide range of cell wall-active antibiotics and other antimicrobial agents including the amide-modified ovispirin-1, bacitracin, teicoplanin, cefotaxime and 10 other beta-lactam antibiotics, chlorpromazine, thioridazine and EGTA. CONCLUSION: Defense against different CAMPs involves not only General signaling pathways but also CAMP-specific ones. These results suggest that CAMPs or a mixture of CAMPs could constitute a potential additive to standard antibiotic treatment.

Drug Metab Dispos. 2009 Dec; 37(12): 2275-2283
Ahlin G, Hilgendorf C, Karlsson J, Szigyarto CA, Uhlén M, Artursson P

The aim of this study was to investigate the gene and protein expression profiles of important drug-transporting proteins in human cell lines commonly used for studies of drug transport mechanisms. Human cell lines used to transiently or stably express single transporters [HeLa, human embryonic kidney (HEK) 293] and leukemia cell lines used to study drug resistance by ATP-binding cassette transporters (HL-60, K562) were investigated and compared with organotypic cell lines (HepG2, Saos-2, Caco-2, and Caco-2 TC7). For gene expression studies, real-time polymerase chain reaction was used, whereas monospecific polyclonal antibodies were generated and used to investigate protein expression by immunohistochemistry. Thirty-six transporters were studied for gene expression, and nine were studied for protein expression. The antibodies were validated using expression patterns in human tissues. Finally, the function of one ubiquitously expressed transporter, MCT1/SLC16A1, was investigated using [(14)C]lactic acid as a substrate. In General, the adherent cell lines (HeLa, HEK293) displayed low transporter expression, and the expression patterns were barely affected by transfection. The leukemia cell lines (K562, HL-60) and Saos-2 also had low endogenous transporter expression, whereas the organotypic cell lines (HepG2 and Caco-2) showed higher expression of some transporters. Comparison of gene and protein expression profiles gave poor correlations, but better agreement was obtained for antibodies with a good validation score, indicating that antibody quality was a significant variable. It is noteworthy that the monocarboxylic acid-transporting protein MCT1 was significantly expressed in all and was functional in most of the cell lines, indicating that MCT1 may be a confounding factor when the transport of small anionic drugs is investigated.

Pharmacogenet Genomics. 2009 Sep; 19(9): 675-84
Siedlinski M, Boezen Hm , Boer JM, Smit HA, Postma DS

OBJECTIVE: The ATP-binding cassette transporter ABCC1 [i.e. multidrug resistance-associated protein 1 (MRP1)] is a membrane-bound pump excreting a variety of xenobiotics from the cell, and thus ABCC1 may play an important role in smoking-related lung function loss and development of chronic obstructive pulmonary disease (COPD). We earlier showed that bronchial epithelium of COPD patients have lower ABCC1 expression than that of healthy controls, with even further decrements in more severe COPD stages. In line with these results, we now aimed to assess effects of ABCC1 single nucleotide polymorphisms (SNPs) on both the level and the longitudinal course of lung function in the General population. METHODS: All 51 prevalent (minor allele frequency >5%) and noncorrelated (r<0.8) ABCC1 SNPs were analyzed in two independent, prospective, population-based cohorts, that is, Doetinchem (n = 1152) and Vlagtwedde-Vlaardingen (n = 1390) studies (three and seven median lung function measurements, respectively, per patient), using linear regression and linear mixed-effect models. RESULTS: SNPs rs4148382 and rs212093 in the 3'-ABCC1 region were significantly associated with a higher and lower forced expiratory volume in 1 s (FEV1), respectively, in both the cohorts. Another rs35621 SNP (intron 14) was significantly associated with a highly excessive FEV1 decline in both cohorts. All replicated associations were additionally confirmed by permutation testing. CONCLUSION: This is the first study showing a significant relationship between ABCC1 SNPs and lung function in two independent cohorts. These SNPs are therefore putative candidates for studies aiming to prevent COPD and investigating pharmacogenetics in established COPD.

PLoS One. 2009; 4(8): e6656
Martins A, Spengler G, Rodrigues L, Viveiros M, Ramos J, Martins M, Couto I, Fanning S, Pagès JM, Bolla JM, Molnar J, Amaral L

BACKGROUND: Resistance Nodulation Division (RND) efflux pumps of Escherichia coli extrude antibiotics and toxic substances before they reach their intended targets. Whereas these pumps obtain their energy directly from the proton motive force (PMF), ATP-Binding Cassette (ABC) transporters, which can also extrude antibiotics, obtain energy from the hydrolysis of ATP. Because E. coli must pass through two pH distinct environments of the gastrointestinal system of the host, it must be able to extrude toxic agents at very acidic and at near neutral pH (bile salts in duodenum and colon for example). The herein described study examines the effect of pH on the extrusion of ethidium bromide (EB). METHODOLOGY/PRINCIPAL FINDINGS: E. coli AG100 and its tetracycline induced progeny AG100(TET) that over-expresses the acrAB efflux pump were evaluated for their ability to extrude EB at pH 5 and 8, by our recently developed semi-automated fluorometric method. At pH 5 the organism extrudes EB without the need for metabolic energy (glucose), whereas at pH 8 extrusion of EB is dependent upon metabolic energy. Phe-Arg beta-naphtylamide (PAbetaN), a commonly assumed inhibitor of RND efflux pumps has no effect on the extrusion of EB as others claim. However, it does cause accumulation of EB. Competition between EB and PAbetaN was demonstrated and suggested that PAbetaN was preferentially extruded. A K(m) representing competition between PAbetaN and EB has been calculated. CONCLUSIONS/SIGNIFICANCE: The results suggest that E. coli has two General efflux systems (not to be confused with a distinct efflux pump) that are activated at low and high pH, respectively, and that the one at high pH is probably a putative ABC transporter coded by msbA, which has significant homology to the ABC transporter coded by efrAB of Enterococcus faecalis, an organism that faces similar challenges as it makes its way through the toxic intestinal system of the host.

FEBS J. 2009 Sep; 276(18): 5191-202
Okuda T, Furukawa K, Nakayama K

Abnormal biosynthesis of globotriaosylceramide (Gb3) is known to be associated with Gb3-related diseases, such as Fabry disease. The Gb3 synthase gene (Gb3S) codes for alpha1,4-galactosyltransferase, which is a key enzyme involved in Gb3 biosynthesis in vivo. Transcriptional repression of Gb3S is a way to control Gb3 biosynthesis and may be a suitable target for the treatment of Gb3-related diseases. To find a transcriptional inhibitor for Gb3S, we developed a convenient cell-based chemical screening assay system by constructing a fusion gene construct of the human Gb3S promoter and a secreted luciferase as reporter. Using this assay, we identified 2-deoxy-D-glucose as a potent inhibitor for the Gb3S promoter. In cultured cells, 2-deoxy-D-glucose markedly reduced endogenous Gb3S mRNA levels, resulting in a reduction in cellular Gb3 content and a corresponding accumulation of the precursor lactosylceramide. Moreover, cytokine-induced expression of Gb3 on the cell surface of endothelial cells, which is closely related to the onset of hemolytic uremic syndrome in O157-infected patients, was also suppressed by 2-deoxy-D-glucose treatment. These results indicate that 2-deoxy-D-glucose can control Gb3 biosynthesis through the inhibition of Gb3S transcription. Furthermore, we demonstrated the General utility of our novel screening assay for the identification of new inhibitors of glycosphingolipid biosynthesis.

BMC Genet. 2009; 10: 42
Nakano M, Miwa N, Hirano A, Yoshiura K, Niikawa N

BACKGROUND: Two types of cerumen occur in humans: the wet type with brownish, sticky earwax, and the dry type with a lack of or reduced ceruminous secretion. The wet type is common in populations of European and African origin, while the dry type is frequently seen in Eastern Asian populations. An association between axillary odor and the wet-type earwax was first identified approximately 70 years ago. The data were based on a phenotypical analysis of the two phenotypes among the Japanese by a researcher or by self-declaration of the subjects examined, and were not obtained using definite diagnostic methods. Recently, we identified a single-nucleotide polymorphism (SNP; rs17822931) of the ABCC11 gene as the determinant of the earwax types. In the present study, to determine whether the SNP can serve as a diagnostic marker for axillary osmidrosis (AO), we examined genotypes at rs17822931 in 79 Japanese AO individuals. AO was defined here as a clinical condition of individuals with a deep anxiety regarding axillary odor and had undergone the removal of bilateral axillary apocrine glands. RESULTS: A comparison of the frequencies of genotypes at rs17822931 in the 79 AO individuals and in 161 Japanese from the General population showed that AO was strongly associated with the wet earwax genotype. A total of 78 (98.7%) of 79 AO patients had either the GG or GA genotype, while these genotypes were observed in 35.4% (57/161) of the subjects from the General population (p < 1.1 x 10(-24), by Fisher's exact test). CONCLUSION: The strong association between the wet-earwax associated ABCC11-genotypes (GG and GA) and AO identified in this study indicates that the genotypes are good markers for the diagnosis of AO. In addition, these results suggest that having the allele G is a prerequisite for the axillary odor expression. In other words, the ABCC11 protein may play a role in the excretory function of the axillary apocrine gland. Together, these results suggest that when an AO individual visiting a hospital is diagnosed with dry-type earwax by ABCC11-genotyping, surgical removal of their axillary glands may not be indicated.

J Lipid Res. 2009 Jul 26;
Bojanic DD, Tarr PT, Gale GD, Smith DJ, Bok D, Chen B, Nusinowitz S, Lovgren-Sandblom A, Bjorkhem I, Edwards PA

ABCG1 and ABCG4 are highly homologous members of the ATP binding cassette (ABC) transporter family that regulate cellular cholesterol homeostasis. In adult mice, ABCG1 is known to be expressed in numerous cell types and tissues whereas ABCG4 expression is limited to the central nervous system (CNS). Here we show significant differences in expression of these two transporters during development. Examination of ss-galactosidase-stained tissue sections from ABCg1-/-LacZ and ABCg4-/-LacZ knock-in mice shows that ABCG4 is highly but transiently expressed both in hematopoietic cells and in enterocytes during development. In contrast, ABCG1 is expressed in macrophages and in endothelial cells of both embryonic and adult liver. We also show that ABCG1 and ABCG4 are both expressed as early as E12.5 in the embryonic eye and developing CNS. Loss of both ABCG1 and ABCG4 results in accumulation in the retina and/or brain of oxysterols, in altered expression of LXR and SREBP-2 target genes, and in a stress-response gene. Finally, behavioral tests show that ABCg4-/- mice have a General deficit in associative fear memory. Together, these data indicate that loss of ABCG1 and/or ABCG4 from the CNS result in changes in metabolic pathways and in behavior.

J Clin Endocrinol Metab. 2009 Oct; 94(10): 3931-8
Zatelli MC, Minoia M, Molè D, Cason V, Tagliati F, Margutti A, Bondanelli M, Ambrosio MR, degli Uberti E

CONTEXT: GH and IGF-I are known to promote breast carcinogenesis. Even if breast cancer (BC) incidence is not increased in female acromegalic patients, mortality is greater as compared with General population. OBJECTIVE: The objective of the study was to evaluate whether GH/IGF-I excess might influence BC response to chemotherapy. DESIGN: We evaluated GH and IGF-I effects on cell proliferation of a BC cell line, MCF7 cells, in the presence of doxorubicin (Doxo), frequently used in BC chemotherapy, and the possible mechanisms involved. RESULTS: GH and IGF-I induce MCF7 cell growth in serum-free conditions and protect the cells from the cytotoxic effects of Doxo. GH effects are direct and not mediated by IGF-I because they are apparent also in the presence of an IGF-I receptor blocking antibody and disappear in the presence of the GH antagonist pegvisomant. The expression of the MDR1 gene, involved in resistance to chemotherapeutic drugs, was not induced by GH. In addition, c-fos transduction was reduced by Doxo, which prevented GH stimulatory effects. Pegvisomant inhibited basal and GH-induced c-fos promoter transcriptional activity. Autocrine GH action is ruled out by the lack of endogenous GH expression in this MCF7 cell strain. CONCLUSIONS: These data indicate that GH can directly induce resistance to chemotherapeutic drugs with a mechanism that might involve GH-induced early gene transcription and support the hypothesis that GH excess can hamper BC treatment, possibly resulting in an increased mortality.

PLoS One. 2009; 4(7): e6214
Deniaud A, Goulielmakis A, Covès J, Pebay-Peyroula E

BACKGROUND: Until very recently, AcrB was the only Resistance Nodulation and cell Division transporter for which the structure has been elucidated. Towards a General understanding of this protein family, CusA and AcrB were compared. METHODOLOGY/PRINCIPAL FINDINGS: In dodecylmaltoside, AcrB crystallised in many different conditions, while CusA does not. This could be due to the difference in dynamic between these proteins as judged from limited proteolysis assays. Addition of various compounds, in particular heavy metal cations, stabilises CusA. CONCLUSION/SIGNIFICANCE: This approach could constitute a first step towards CusA crystallisation.

Neoplasma. 2009; 56(5): 371-8
Wang YH, Li F, Luo B, Wang XH, Sun HC, Liu S, Cui YQ, Xu XX

We used flow cytometry and a DNA-binding dye efflux assay to isolate a side population (SP) of cells with stem cell characteristics from the human pancreatic carcinoma cell line, PANC-1. Non-obese diabetic/severe combined immunodeficiency mouse xenograft experiments showed that SP cells were enriched in tumor initiating capability compared with non-SP cells. Cultured SP cells were able to differentiate into daughter cells and non-SP cells, through asymmetric division. Our study demonstrated that SP cells had high drug-resistance, both in vivo and in vitro. SP cells also showed significantly higher levels of mRNA expression for CD133, ABCG2 and Notch1, when compared to non-SP cells. Furthermore, xenografted tumors derived from injected SP cells and treated with gemcitabine had more CD133+ cells than untreated ones. We therefore suggest that these SP cells from the PANC-1 cell line were enriched with cancer stem cells.

Int J Mol Med. 2009 Aug; 24(2): 233-46
Yoshida T, Kato K, Yokoi K, Oguri M, Watanabe S, Metoki N, Yoshida H, Satoh K, Aoyagi Y, Nishigaki Y, Nozawa Y, Yamada Y

The purpose of the present study was to identify genetic variants that confer susceptibility to chronic kidney disease (CKD) in individuals with low or high serum concentrations of triglycerides (TG), high-density lipoprotein (HDL)-cholesterol, or low-density lipoprotein (LDL)-cholesterol, thereby contributing to the personalized prevention of CKD in such individuals. The study population comprised 5944 Japanese individuals, including 1706 subjects with CKD [estimated glomerular filtration rate (eGFR)<60 ml/min/1.73 m2] and 4238 controls (eGFR>or=60 ml/min/1.73 m2). The genotypes for 296 polymorphisms of 202 candidate genes were determined. The Chi-square test, multivariable logistic regression analysis with adjustment for covariates, and a stepwise forward selection procedure revealed that seven different polymorphisms were significantly (P<0.005) associated with the prevalence of CKD in individuals with low or high serum concentrations of TG or HDL- or LDL-cholesterol: the Aright curved arrow G (Glu23Lys) polymorphism of KCNJ11 and the 125592Cright curved arrow A (Thr431Asn) polymorphism of ROCK2 in individuals with low serum TG; the 734Cright curved arrow T (Thr254Ile) polymorphism of ACAT2 and the Cright curved arrow G (Gln27Glu) polymorphism of ADRB2 in individuals with high serum TG; the -1607/1Gright curved arrow 2G polymorphism of MMP1 in individuals with low serum HDL-cholesterol; the Gright curved arrow A (Val158Met) polymorphism of COMT in individuals with low serum LDL-cholesterol; the 584Gright curved arrow A (Gln192Arg) polymorphism of PON1 in individuals with high serum LDL-cholesterol. No polymorphism was associated with CKD in individuals with high serum HDL-cholesterol. These results suggest that polymorphisms associated with CKD may differ among individuals with different lipid profiles. Stratification of subjects according to lipid profiles may thus be important for personalized prevention of CKD based on genetic information.

PLoS Pathog. 2009 Jun; 5(6): e1000486
Coleman JJ, Mylonakis E

Pathogens must be able to overcome both host defenses and antimicrobial treatment in order to successfully infect and maintain colonization of the host. One way fungi accomplish this feat and overcome intercellular toxin accumulation is efflux pumps, in particular ATP-binding cassette transporters and transporters of the major facilitator superfamily. Members of these two superfamilies remove many toxic compounds by coupling transport with ATP hydrolysis or a proton gradient, respectively. Fungal genomes encode a plethora of members of these families of transporters compared to other organisms. In this review we discuss the role these two fungal superfamilies of transporters play in virulence and resistance to antifungal agents. These efflux transporters are responsible not only for export of compounds involved in pathogenesis such as secondary metabolites, but also export of host-derived antimicrobial compounds. In addition, we examine the current knowledge of these transporters in resistance of pathogens to clinically relevant antifungal agents.

Cell Mol Life Sci. 2009 Oct; 66(19): 3111-26
Kos V, Ford RC

The ATP-binding cassette family is one of the largest groupings of membrane proteins, moving allocrites across lipid membranes, using energy from ATP. In bacteria, they reside in the inner membrane and are involved in both uptake and export. In eukaryotes, these transporters reside in the cell's internal membranes as well as in the plasma membrane and are unidirectional-out of the cytoplasm. The range of substances that these proteins can transport is huge, which makes them interesting for structure-function studies. Moreover, their abundance in nature has made them targets for structural proteomics consortia. There are eight independent structures for ATP-binding cassette transporters, making this one of the best characterised membrane protein families. Our understanding of the mechanism of transport across membranes and membrane protein structure in General has been enhanced by recent developments for this family.

Oncol Rep. 2009 Jul; 22(1): 73-80
Chen X, Zhang M, Liu LX

Arsenic trioxide has been used as a therapeutic agent for acute promyelocytic leukemia and recently for some solid tumors. Although arsenic trioxide has been shown to significantly inhibit the growth of solid tumor cells in vitro, clinical trials indicate that arsenic trioxide alone is pool active against non-hematologic malignant diseases. To understand the mechanisms of arsenic resistance in solid tumor cells, we established two arsenic-resistant solid tumor cell lines, HepG2/AS and SGC7901/AS, isolated from human liver cancer cell line HepG2 and human gastric cancer cell line SGC7901, respectively, by a series of stepwise selections via treatment with increasing concentrations of arsenic trioxide. Three ABC transporter proteins, ABCB1, ABCC1 and ABCC2, were expressed increasingly and differently in two arsenic-resistant cell lines. Further, tumor suppressor p53 was overexpressed in two arsenic-resistant cell lines, but the levels of p53 mediators MDM2 and gankyrin, which regulate the ubiquitination of p53, increased simultaneously. In addition, an increase in the phosphorylation of Rb at Ser795 in the two cell lines might also result from the presence of MDM2 and gankyrin, which suggest that the inactivation of p53 and Rb contribute to drug resistance. These two arsenic-resistant solid tumor cell lines, HepG2/AS and SGC7901/AS, may be useful for studying the mechanism of arsenic resistance in solid tumors and may provide a way to overcome it.

J Cancer Res Clin Oncol. 2009 Dec; 135(12): 1675-84
Lin Q, Geng J, Ma K, Yu J, Sun J, Shen Z, Bao G, Chen Y, Zhang H, He Y, Luo X, Feng X, Zhu J

PURPOSE: To identify the DNA methylation biomarkers for the detection of the stage I non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: The methylated state of p16INK4A, ESR1, HOX9, RASSF1A, DAPK1, PTEN, ABCB1, MGMT, APC and MT1G genes that have been reported frequently methylated in lung cancer was determined using methylation-specific PCR in four lung cancer cell lines, 124 cancer tissues of the stage I NSCLC and 26 non-cancerous disease tissues. RESULT: The RASSF1A (53/124, 42.74%), APC (49/123, 39.52%), ESR1 (37/124, 29.84%), ABCB1 (31/124, 24.19%, MT1G (25/124, 20.16%) and HOXC9 (17/124, 13.71%) genes were more frequently methylated in the lung tissue from the stage I NSCLC than the non-cancerous lesion patients (2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.01; 2/26, 7.69%, P < 0.05; 1/26, 3.85% P < 0.01; 0/26 0%, P value: <0.01; 0/26, 0%, P < 0.05, respectively). p16INK4A was methylated in 28/124 (22.56%) of cancer tissues and 2/26 (7.69%) of non-cancerous tissues (P value >0.05). No significant association between the methylated state of the genes and the smoking, age or the pathologic types (squamous carcinoma, adenoma and the mixed types) was found. However, p16INK4A methylation was more frequently detected in the male (23/80, 28.75%) than the female (5/44, 11.36%, P > 0.05) patients. MGMT was barely methylated: 1/67, 1.49%), while DAPK1 and PTEN were not at all methylated in the cancer groups. CONCLUSIONS: Methylation analysis in tissue of RASSF1A, APC, ESR1, ABCB1 and HOXC9 genes confirmed 79.8% of the existing diagnosis for the stage I NSCLC at specificity: 73.1%. The insufficiency of predicting disease onset in China, using the previously recommended targets (MGMT, DAPK1 and PTEN) in the United States reflects a potential disease disparity between these two populations. Alternatively, methylated state of this set of genes may be more specific to the late rather than the early stage of NSCLC.

Aquat Toxicol. 2009 Jul 26; 93(4): 188-95
Venn AA, Quinn J, Jones R, Bodnar A

The deleterious impacts of marine pollutants on reef corals and their symbiotic algae are an important element of global coral reef decline. In the current study we examined the impacts of toxicants on the reef coral Montastraea franksi by analysing the expression of three stress-related genes belonging to the coral host, using Taqman real-time quantitative reverse transcription-PCR. Gene expression profiles of P-glycoprotein (or multi-xenobiotic resistance protein) (P-gp); heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) were examined following 4 and 8h exposures to the heavy metal copper (3, 10, 30 and 100 microgL(-1)) or the third generation oil dispersant Corexit9527 (1, 5, 10 and 50 ppm). Additionally, the expression of P-gp was examined following exposure to 0.5 and 5 microM concentrations of the chemotherapeutic drug vinblastine, a classic substrate of P-gp. The expression of P-gp increased significantly in corals treated with vinblastine and also increased following exposure to copper and Corexit9527. Hsp70, and to a lesser extent Hsp90 expression increased following exposure to copper and Corexit9527 indicating a General cellular stress response. Densities of symbiotic algae in the tissues of the corals did not change significantly during the experiments, nor was any loss or paling of coral tissues observed. These findings provide important insight into how corals defend themselves against pollution and complement ongoing initiatives developing molecular biomarkers of stress in reef-building corals.

Biol Chem. 2009 Aug; 390(8): 815-34
Hellmich UA, Glaubitz C

In order to fulfill their function, membrane transport proteins have to cycle through a number of conformational and/or energetic states. Thus, understanding the role of conformational dynamics seems to be the key for elucidation of the functional mechanism of these proteins. However, membrane proteins in General are often difficult to express heterologously and in sufficient amounts for structural studies. It is especially challenging to trap a stable energy minimum, e.g., for crystallographic analysis. Furthermore, crystallization is often only possible by subjecting the protein to conditions that do not resemble its native environment and crystals can only be snapshots of selected conformational states. Nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy are complementary methods that offer unique possibilities for studying membrane proteins in their natural membrane environment and for investigating functional conformational changes, lipid interactions, substrate-lipid and substrate-protein interactions, oligomerization states and overall dynamics of membrane transporters. Here, we review recent progress in the field including studies from primary and secondary active transporters.

Minerva Urol Nefrol. 2009 Jun; 61(2): 91-107
Goebell PJ

In oncology patients and clinicians are confronted with the search for measures which could help to elicit the individual patient's risk of future outcome, such as recurrence of disease after primary treatment, response to chemo-therapy or a General outline on the aggressiveness of a given lesion. In patient counselling, the emerging role of evidence based treatment choices reveals with cumulative certainty that the available information is inconclusive. This review will focus on current investigations of determinants to predict response to chemotherapy in advanced bladder cancer or to define prognosis of patients prior to any definite treatment. It will discuss the current evidence for the current systemic treatment options and highlight the many promising approaches of implementing markers either as a basis for a clinical decision in combination with other prognosticators (to better detect individuals at risk or to avoid unnecessary invasive procedures) or as a possible part of relevant pathways to be targeted. It will also discuss the role of biological markers with regards to the relevant clinical question and provide the current evidence to each field. It will highlight the need to further harmonize terminology, approaches and circumstances under which markers are evaluated and will provide suggestions for General methodological principles and guidelines for design, conduct, analysis and reporting of marker studies. The exploration of the current aspects of marker research may outline why collaborative, multicentre, and multidisciplinary efforts should be an integral part of future studies.

Pharm Res. 2009 Aug; 26(8): 1816-31
Matsson P, Pedersen JM, Norinder U, Bergström CA, Artursson P

PURPOSE: To study the inhibition patterns of the three major human ABC transporters P-gp (ABCB1), BCRP (ABCG2) and MRP2 (ABCC2), using a dataset of 122 structurally diverse drugs. METHODS: Inhibition was investigated in cellular and vesicular systems over-expressing single transporters. Computational models discriminating either single or General inhibitors from non-inhibitors were developed using multivariate statistics. RESULTS: Specific (n = 23) and overlapping (n = 19) inhibitors of the three ABC transporters were identified. GF120918 and Ko143 were verified to specifically inhibit P-gp/BCRP and BCRP in defined concentration intervals, whereas the MRP inhibitor MK571 was revealed to inhibit all three transporters within one log unit of concentration. Virtual docking experiments showed that MK571 binds to the ATP catalytic site, which could contribute to its multi-specific inhibition profile. A computational model predicting General ABC inhibition correctly classified 80% of both ABC transporter inhibitors and non-inhibitors in an external test set. CONCLUSIONS: The inhibitor specificities of P-gp, BCRP and MRP2 were shown to be highly overlapping. General ABC inhibitors were more lipophilic and aromatic than specific inhibitors and non-inhibitors. The identified specific inhibitors can be used to delineate transport processes in complex experimental systems, whereas the multi-specific inhibitors are useful in primary ABC transporter screening in drug discovery settings.