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Background: Seaweeds have a long history of use in Asian countries as functional foods, medicinal herbs, and the treatment of cancer. Polysaccharides from various seaweeds have shown anti-tumor activity. Cholangiocarcinoma (CCA), often with metastatic disease, is highly prevalent in Thailand as a consequence of liver fluke infection. Recently, we extracted sulfated galactans (SG) from Gracilaria fisheri (G. fisheri), a south east Asian seaweed, and found it exhibited anti-proliferation effect on CCA cells.Purpose: In the present study, we evaluated the anti-migration activity of SG on CCA cells and its underlined mechanism.Methods: CCA cells were treated with SG alone or drugs targeting to epidermal growth factor (EGF) receptor (EGFR) or pretreated with SG prior to incubation with EGF. Anti-migration activity was determined using a scratch wound-healing assay and zymography. Immunofluorescence staining and western blotting were used to investigate EGFR signaling mediators.Results: Under basal condition, SG reduced the migration rate of CCA, which was correlated with a decrease in the active-form of matrix metalloproteinases-9. SG decreased expression of phosphorylated focal adhesion kinase (FAK), but increased expression of E-cadherin to promote cells stasis. Moreover, phosphorylation of EGFR and extracellular signal-regulated kinases (ERK), known to stimulate growth of cancer cells, was blocked in a comparable way to EGFR inhibitors Cetuximab and Erlotinib. Pretreatment cells with SG attenuated EGF induced phosphorylation of EGFR, ERK and FAK.Conclusion: This study reveals that SG from G. fisheri retards migration of CCA cells, and its mechanism of inhibition is mediated, to some extent, by inhibitory effects on MAPK/ERK signal transduction pathway. Our findings suggest that there may be a therapeutic potential of SG in CCA treatment. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, Clostridium spp. have rapidly reemerged as human and animal pathogens. The detection and identification of pathogenic Clostridium spp. is therefore critical for clinical diagnosis and antimicrobial therapy. Traditional diagnostic techniques for clostridia are laborious, are time consuming, and may adversely affect the therapeutic outcome. In this study, we developed an oligonucleotide diagnostic microarray for pathogenic Clostridium spp. The microarray specificity was tested against 65 Clostridium isolates. The applicability of this microarray in a clinical setting was assessed with the use of mock stool samples. The microarray was successful in discriminating at least 4 species with the limit of detection as low as 104 CFU/mL. In addition, the pattern of virulence and antibiotic resistance genes of tested strains were determined through the microarrays. This approach demonstrates the high-throughput detection and identification of Clostridium spp. and provides advantages over traditional methods. Microarray-based techniques are promising applications for clinical diagnosis and epidemiologic investigations. [Copyright &y& Elsevier]

Summary: ATP-binding cassette (ABC) multidrug transporters have been associated with chemoresistance, which is a major obstacle in attempts to improve clinical outcome of patients with nasopharyngeal carcinoma (NPC). In this study, we investigated 3 ABC multidrug transporters including MDR1, MRP1, and BCRP for their potential as prognostic indicators in patients with NPC. We examined the protein expression profiles of MDR1, MRP1, and BCRP in NPC tissues from 60 patients with advanced stages who were treated with radiotherapy and concurrent chemotherapy. The clinicopathologic features, patterns of treatment failure, and survival data were compared with the transporter expression. Univariate analyses were performed to determine the prognostic factors that influenced treatment failure and patient survival. We found that MRP1 expression was strongly predictive of both 5-year survival (P = .025) and disease-free survival (P < .001). However, neither MDR1 nor BCRP expression was correlated with the clinicopathologic parameters. Interestingly, the incidence of recurrence and metastasis for patients in the MRP1-positive group was significantly higher than that in the MRP1-negative group (P = .003). With multivariate analysis, MRP1 expression at the time of diagnosis before the treatment was identified as an independent prognostic factor for both 5-year survival (P = .041) and disease-free survival (P = .001). MRP1 expression can therefore be used as a potent molecular risk factor and a guide for chemotherapeutic regimens in patients with advanced stages of NPC. [Copyright &y& Elsevier]

LmrA is an ATP binding cassette (ABC) multidrug transporter in Lactococcus lactis that is a structural and functional homologue of the human multidrug resistance P-glycoprotein MDR1 (ABCB1). LmrA is also homologous to MsbA, an essential ABC transporter in Escherichia coli involved in the trafficking of lipids, including Lipid A. We have compared the substrate specificities of LmrA and Msba in detail. Surprisingly, LmrA was able to functionally substitute for a temperature-sensitive mutant Msba in E. coli WD2 at non-permissive temperatures, suggesting that LmrA could transport Lipid A. LmrA also exhibited a Lipid A-stimulated, vanadate-sensitive ATPase activity. Reciprocally, the expression of Msba conferred multidrug resistance on E. coli. Similar to LmrA, Msba interacted with photoactivatable substrate [³H]azidopine, displayed a daunomycin, vinblastine, and Hoechst 33342-stimulated vanadateosensitive ATPase activity, and mediated the transport of ethidium from cells and Hoechst 33342 in proteoliposomes containing purified and functionally reconstituted protein. Taken together, these data demonstrate that Msba and LmrA have overlapping substrate specificities. Our observations imply the presence of structural elements in the recently published crystal structures of Msba in E. coli and Vibrio cholera (Chang, G., and Roth, C. B. (2001) Science 293, 1793-1800; Chang, G. (2003) J. Mol. Biol. 330, 419-430) that support drugprotein interactions and suggest a possible role for LmrA in lipid trafficking in L. lactis. [ABSTRACT FROM AUTHOR]

Reports on a study by researchers from the U.S., which concludes that the substrate specificity of breast cancer resistance protein partly overlaps with that proposed for adenosine triphosphate-binding cassette G (ABCG) 1 and ABCG5/ABCG8. Immunodetection of BCRP in the cytoplasmic membrane of Lactococcus lactis.

Clostridioides difficile , a gram-positive, toxin-producing, spore-forming anaerobe, is a major cause of antibiotic-associated diarrhoea. The bacterium's intrinsic drug resistance limits current treatment options to fidaxomicin and vancomycin for initial episodes, with anti-toxin B monoclonal antibody or faecal microbiota transplantation recommended for complicated or recurrent cases. This underscores the urgent need for novel therapeutics. In this study, we screened the MMV Pathogen Box at a 10 µM concentration against C. difficile R20291. Primary hits were evaluated for minimum inhibitory concentrations (MIC), killing kinetics, and biofilm inhibition. Bacterial cytological profiling (BCP) and transmission electron microscopy (TEM) were employed to study the mode of action. MMV676558 was further tested in a mouse model to assess survival, histopathology, and gut microbiota effects. We identified nineteen hits that inhibited over 50 % of C. difficile growth. MIC assays revealed three hits with MICs below 16 µg/mL: MMV676558, MMV688755, and MMV690027. These hits were effective against various C. difficile ribotypes. Killing kinetics were comparable or superior to vancomycin and fidaxomicin, and biofilm assays showed inhibitory effects. BCP and TEM analyses suggested membrane function disruption as the mode of action. Furthermore, MMV676558 demonstrated a protective effect in mice, with favourable histopathology and gut microbiota profiles. Given the urgent threat posed by C. difficile antibiotic resistance, discovering new treatments is a top priority. Our study identified three promising hits from the MMV Pathogen Box, with MMV676558 showing significant in vivo potential for further evaluation. [ABSTRACT FROM AUTHOR]

Abstract: ATP-binding cassette (ABC) multidrug transporters confer resistance in human cancer cells as well as in pathogenic microorganisms by mediating the extrusion of various chemotherapeutic drugs out of the cell. In aquatic invertebrates, the presence of ABC transporters which are involved in the multi-xenobiotic resistance has been demonstrated. However, most studies have been confined to the MDR1 subfamily. In the present study, we characterized the expression and localization of the ABC multidrug transporters including MDR1, MRP1 and BCRP subfamily in the Indian-rock oyster Saccostrea forskali. To our knowledge, these data represent one of the first reports on the orthologues of MRP1 and BCRP in marine invertebrates. Furthermore, the observations of (i) the expression of the ABC multidrug proteins in detoxifying tissues; (ii) the induction of these transporters upon exposure to an environmental organic pollutant tributyltin (TBT); and (iii) the concentration-dependent inhibition of rhodamine efflux by TBT imply a possible role of these proteins in the export of TBT. Our findings along with previous studies suggest that the ABC multidrug transporters act as a detoxifying mechanism of various toxic agents including TBT in aquatic organisms. [Copyright &y& Elsevier]

The serine/arginine-rich protein kinase-1 (SRPK1) is an enzyme that has an essential role in regulating numerous aspects of mRNA splicing. SRPK1 has been reported to be overexpressed in multiple cancers, suggesting it as a promising therapeutic target in oncology. No previous studies reported the role of SRPK1 in cholangiocarcinoma (CCA) cells. This study aimed to examine the expression of SRPK1 and the effects of SRPK1 inhibition on the viability and angiogenesis activity of CCA cells using a selective SRPK1 inhibitor, SPHINX31. Here, we demonstrate that SPHINX31 (0.3‐10 μM) had no inhibitory effects on CCA cells' viability and proliferation. However, SPHINX31 decreased the mRNA expression of pro-angiogenic VEGF-A 165 a isoform. In addition, SPHINX31 attenuated SRSF1 phosphorylation and nuclear localization, and increased the ratio of VEGF-A 165 b/total VEGF-A proteins. Moreover, when HUVECs were grown in conditioned medium from SPHINX31-treated CCA cells, migration slowed, and tube formation decreased. The present study demonstrates that targeting SRPK1 in CCA cells effectively attenuates angiogenesis by suppressing pro-angiogenic VEGF-A isoform splicing. These findings suggest a potential therapeutic treatment using SRPK1 inhibitors for the inhibition of angiogenesis in cholangiocarcinoma. • SRPK1 inhibitor suppressed pro-angiogenic VEGF-A 165 a mRNA expression in CCA cells • SRPK1 inhibitor attenuated SRSF1 phosphorylation and nuclear translocation • SRPK1 inhibitor-treated cells increased anti-angiogenic VEGFA- 165 b protein level • HUVECs cultured with high VEGF-A 165 b medium formed less capillary-like tubes [ABSTRACT FROM AUTHOR]