These data (1) provide the first evidence for ongoing myofibrillar degradation and increased cardiac troponin I levels in patients with advanced heart failure and (2) show potential usefulness of cardiac troponin I as a specific and sensitive new serum marker molecule in severe congestive heart failure.

Background: B-Type natriuretic peptide (BNP 1-32 ) as well as the N-terminal fragment of the prohormone containing residues 1-76 (NT-proBNP 1-76 ), both cleavage products of the precursor proBNP 1-108 , are reported to be powerful markers for prognosis and risk stratification of heart failure. However, the intact precursor also circulates in the bloodstream. Assays for the detection of these cleavage products have been developed, but most of these assays may overestimate the concentrations of the cleavage products because they also measure the precursor form. It is therefore important to develop an immunoassay that specifically measures solely proBNP 1-108 in plasma. Methods: After carefully designing the peptide used to immunize mice, we selected a specific monoclonal antibody (mAb Hinge76) that recognizes the cleavage site of proBNP 1-108 , an epitope present only in the precursor form. mAb Hinge76 recognizes recombinant proBNP 1-108 in a dose-dependent manner, without any significant cross-reactivity with either recombinant NT-proBNP 1-76 or synthetic BNP 1-32 . By combining mAb Hinge76 with a polyclonal antibody directed against BNP 1-32 , we were able to set up a proBNP 1-108 -specific sandwich immunoassay able to confirm the presence of proBNP 1-108 in blood samples. Results: From a cohort of 50 healthy persons and 170 patients with congestive heart failure (CHF), our assay was able to differentiate healthy individuals from CHF patients (P <0.005). Interestingly, plasma proBNP 1-108

Overcoming drug resistance has become an important issue in cancer chemotherapy. Among all known mechanisms that confer resistance, active efflux of chemotherapeutic agents by proteins from the ATP-binding cassette family has been extensively reported. The aim of the present study was to determine the involvement of ABCG2 in resistance to SN38 (the active metabolite of irinotecan) in colorectal cancer. By progressive exposure to increasing concentrations of SN38, we isolated 2 resistant clones from the human colon carcinoma cell line HCT116. These clones were 6-and 53-fold more resistant to SN38 than the HCT116-derived sensitive clone. Topoisomerase I expression was unchanged in our resistant variants. The highest resistance level correlated with an ABCG2 amplification. This overexpression was associated with a marked decrease in the intracellular accumulation of SN38. The inhibition of ABCG2 function by Ko143 demonstrated that enhanced drug efflux from resistant cells was mediated by the activity of ABCG2 protein and confirmed that ABCG2 is directly involved in acquired resistance to SN38. Furthermore, we show, for the first time in clinical samples, that the ABCG2 mRNA content in hepatic metastases is higher after an irinotecan-based chemotherapy than in irinotecan-naive metastases. In conclusion, this study supports the potential involvement of ABCG2 in the development of irinotecan resistance in vivo. © 2004 Wiley-Liss, Inc. Key words: colorectal cancer; ABCG2; SN38; drug resistanceChemotherapeutic drug resistance is a frequent cause of treatment failure in colorectal cancer patients. Understanding the cellular mechanisms that lead to this resistance should permit an improvement in the treatment of colorectal cancer. Irinotecan (CPT-11), a semisynthetic water-soluble derivative of camptothecin, is widely used for the treatment of metastatic colon cancer. 1 CPT-11 is a prodrug converted by carboxylesterases into its active form, SN38. 2 Like other camptothecin derivatives, SN38 exerts its cytotoxic activity through the inhibition of topoisomerase I. Human topoisomerase I is a 100 kDa nuclear enzyme needed for replication and transcription and causing single strand breaks in DNA, thus permitting relaxation of supercoiled DNA. 3 SN38 interferes with topoisomerase I function by forming stable ternary complexes at the DNA breakage points and stopping the topoisomerase I-mediated religation. 4 Cellular resistance to camptothecin derivatives can result from a decrease in cellular drug accumulation, alterations in the structure or location of topoisomerase I, changes in the cellular response to the drug-DNA-enzyme ternary complex formation 5 or increased glucuronidation of SN38, resulting in an inactivation of the drug. 6 Members of the ATP-binding cassette (ABC) transporters, notably MDR1 (ABCB1) and MRP1 (ABCC1), confer resistance to chemotherapeutic drugs by active drug efflux. 7,8 Recently, a new member of this family, the ABCG2 transporter also called BCRP 9 or ABCP 10 or MXR 11 has been discovered. This gene, ...

DNA microarray technology enables investigators to measure the expression of several thousand mRNA species simultaneously in a biological specimen. However, the reliability of the microarray technology to detect transcriptional differences representative of the original samples is affected by the quality of the extracted RNA. Thus, it is of critical importance to standardize sample-handling protocols and to perform a quality assessment of RNA preparations. In this report, 59 human tissue samples were used to evaluate the relationships between RNA quality and gene expression. From Affymetrix® GeneChip® array data analysis of these samples, we compared the performance of the 28S/18S ratio, two computer methods (RIN and Degradometer) and our in-house RNA Quality Scale (RQS) in assessing RNA quality. The optimal RNA reliability threshold was determined for each method using statistical discrimination measures. We showed that RQS, RIN and Degradometer have a similar capacity to detect reliable RNA samples whereas the 28S/18S ratio leads to a misleading categorization. Furthermore, we developed a new approach, based on clustering analyses of full chip expression, to control RNA quality after hybridization experiments. The combination of these methods, allowing monitoring of RNA quality prior to and after the hybrizidation experiments, ensured reliable and reproducible microarray data.3

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After validation in an independent cohort of patients, our gene signature could be used as a decision tool to assist oncologists in selecting colorectal cancer patients who could benefit from FOLFIRI chemotherapy, both in the adjuvant and the first-line metastatic setting.

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BackgroundCurrent therapies have succeeded in controlling AIDS pandemic. However, there is a continuing need for new drugs, in particular those acting through new and as yet unexplored mechanisms of action to achieve HIV infection cure. We took advantage of the unique feature of proviral genome to require both activation and inhibition of splicing of viral transcripts to develop molecules capable of achieving long lasting effect on viral replication in humanized mouse models through inhibition of Rev-mediated viral RNA biogenesis.ResultsCurrent HIV therapies reduce viral load during treatment but titers rebound after treatment is discontinued. We devised a new drug that has a long lasting effect after viral load reduction. We demonstrate here that ABX464 compromises HIV replication of clinical isolates of different subtypes without selecting for drug resistance in PBMCs or macrophages. ABX464 alone, also efficiently compromised viral proliferation in two humanized mouse models infected with HIV that require a combination of 3TC, Raltegravir and Tenofovir (HAART) to achieve viral inhibition in current protocols. Crucially, while viral load increased dramatically just one week after stopping HAART treatment, only slight rebound was observed following treatment cessation with ABX464 and the magnitude of the rebound was maintained below to that of HAART for two months after stopping the treatment. Using a system to visualize single HIV RNA molecules in living cells, we show that ABX464 inhibits viral replication by preventing Rev-mediated export of unspliced HIV-1 transcripts to the cytoplasm and by interacting with the Cap Binding Complex (CBC). Deep sequencing of viral RNA from treated cells established that retained viral RNA is massively spliced but importantly, normal cellular splicing is unaffected by the drug. Consistently ABX464 is non-toxic in humans and therefore represents a promising complement to current HIV therapies.ConclusionsABX464 represents a novel class of anti-HIV molecules with unique properties. ABX464 has a long lasting effect in humanized mice and neutralizes the expression of HIV-1 proviral genome of infected immune cells including reservoirs and it is therefore a promising drug toward a functional cure of HIV.Electronic supplementary materialThe online version of this article (doi:10.1186/s12977-015-0159-3) contains supplementary material, which is available to authorized users.