Galectin‐3 in venous thrombosis: A possible new target for improved patient care

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143719/1/rth212087_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143719/2/rth212087.pd

A melanocyte lineage program confers resistance to MAP kinase pathway inhibition

BRAFV600E-mutant malignant melanomas depend on RAF/MEK/ERK (MAPK) signaling for tumor cell growth1. RAF and MEK inhibitors show remarkable clinical efficacy in BRAFV600E melanoma2, 3; however, resistance to these agents remains a formidable challenge2, 4. Global characterization of resistance mechanisms may inform the development of more effective therapeutic combinations. Here, we performed systematic gain-of-function resistance studies by expressing >15,500 genes individually in a BRAFV600E melanoma cell line treated with RAF, MEK, ERK, or combined RAF/MEK inhibitors. These studies revealed a cyclic AMP-dependent melanocytic signaling network not previously associated with drug resistance, including G-protein coupled receptors, adenyl cyclase, protein kinase A and cAMP response element binding protein (CREB). Preliminary analysis of biopsies from BRAFV600E melanoma patients revealed that phosphorylated (active) CREB was suppressed by RAF/MEK-inhibition but restored in relapsing tumors. Expression of transcription factors activated downstream of MAP kinase and cAMP pathways also conferred resistance, including c-FOS, NR4A1, NR4A2 and MITF. Combined treatment with MAP kinase pathway and histone deacetylase inhibitors suppressed MITF expression and cAMP-mediated resistance. Collectively, these data suggest that oncogenic dysregulation of a melanocyte lineage dependency can cause resistance to RAF/MEK/ERK inhibition, which may be overcome by combining signaling- and chromatin-directed therapeutics

Suppression of interferon gene expression overcomes resistance to MEK inhibition in KRAS-mutant colorectal cancer.

Despite showing clinical activity in BRAF-mutant melanoma, the MEK inhibitor (MEKi) trametinib has failed to show clinical benefit in KRAS-mutant colorectal cancer. To identify mechanisms of resistance to MEKi, we employed a pharmacogenomic analysis of MEKi-sensitive versus MEKi-resistant colorectal cancer cell lines. Strikingly, interferon- and inflammatory-related gene sets were enriched in cell lines exhibiting intrinsic and acquired resistance to MEK inhibition. The bromodomain inhibitor JQ1 suppressed interferon-stimulated gene (ISG) expression and in combination with MEK inhibitors displayed synergistic effects and induced apoptosis in MEKi-resistant colorectal cancer cell lines. ISG expression was confirmed in patient-derived organoid models, which displayed resistance to trametinib and were resensitized by JQ1 co-treatment. In in vivo models of colorectal cancer, combination treatment significantly suppressed tumor growth. Our findings provide a novel explanation for the limited response to MEK inhibitors in KRAS-mutant colorectal cancer, known for its inflammatory nature. Moreover, the high expression of ISGs was associated with significantly reduced survival of colorectal cancer patients. Excitingly, we have identified novel therapeutic opportunities to overcome intrinsic and acquired resistance to MEK inhibition in colorectal cancer

A pharmacogenetic candidate gene study of tenofovir-associated Fanconi syndrome

BackgroundTenofovir disoproxil fumarate (TDF) is a widely used antiretroviral agent with favorable efficacy, safety, and tolerability profiles. However, renal adverse events, including the rare Fanconi syndrome (FS), may occur in a small subset of patients treated for HIV infections.ObjectivesThe aim of this study was to identify genetic variants that may be associated with TDF-associated FS (TDF-FS).MethodsDNA samples collected from 19 cases with TDF-FS and 36 matched controls were sequenced, and genetic association studies were conducted on eight candidate genes: ATP-binding cassette (ABC) transporters ABCC2 (MRP2) and ABCC4 (MRP4), solute carrier family members SLC22A6 (OAT1) and SLC22A8 (OAT3), adenylate kinases 2 (AK2) and 4 (AK4), chloride transporter CIC-5 CLCN5, and Lowe syndrome protein OCRL. The functional effects of a single nucleotide polymorphism (SNP) predicted to alter the transport of tenofovir were then investigated in cells expressing an identified variant of ABCC4.ResultsThe case group showed a trend toward a higher proportion of rare alleles. Six SNPs in ABCC2 (three SNPs), ABCC4 (one SNP), and OCRL (two SNPs) were associated with TDF-FS case status; however, this association did not remain significant after correction for multiple testing. Six SNPs, present in OCRL (four SNPs) and ABCC2 (two SNPs), were significantly associated with increased serum creatinine levels in the cases, and this association remained significant after multiple test correction (P < 2 × 10). One synonymous SNP in ABCC2 (rs8187707, P = 2.10 × 10, β = -73.3 ml/min/1.73 m(2)) was also significantly associated with the decreased estimated glomerular filtration rate of creatinine among cases. However, these results were driven by rare SNPs present in a small number of severely affected cases. Finally, a previously uncharacterized, nonsynonymous SNP, rs11568694, that was predicted to alter MRP4 function had no significant effect on tenofovir cellular accumulation in vitro.ConclusionAlthough no single predictive genetic marker for the development of TDF-FS was identified, the findings from our study suggest that rare variants in multiple genes involved in the renal handling of tenofovir, and/or renal cell homeostasis, may be associated with increased susceptibility to TDF-FS

Identification of a New Class of Antifungals Targeting the Synthesis of Fungal Sphingolipids

Visesato Mor, a; Antonella Rella, a; Amir M. Farnoud, a; Ashutosh Singh, a; Mansa Munshi, a; Arielle Bryan, a; Shamoon Naseem, a; James B. Konopka, a; Iwao Ojima, b; Erika Bullesbach, c; Alan Ashbaugh, d; Michael J. Linke, d,e; Melanie Cushion, d,e; Margaret Collins, e; Hari Krishna Ananthula, f; Larry Sallans, q; Pankaj B. Desai, f; Nathan P. Wiederhold, g; Annette W. Fothergill, g; William R. Kirkpatrick, h; Thomas Patterson, h; Lai Hong Wong, i; Sunita Sinha, i; Guri Giaever, i; Corey Nislow, i; Patrick Flaherty, j; Xuewen Pan, k; Gabriele Vargas Cesar, l; Patricia de Melo Tavares, l; Susana Frases, m; Kildare Miranda, l,n; Marcio L. Rodrigues, l,o; Chiara Luberto, p; Leonardo Nimrichter, l; Maurizio Del Poeta, a. Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, USA a; Department of Chemistry and Institute of Chemical Biology and Drug Discovery, Stony Brook University, Stony Brook, New York, USA b; Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, USA c; Department of Veterans Affairs Medical Center, Cincinnati, Ohio, USA d; University of Cincinnati College of Medicine, Cincinnati, Ohio, USA e; Department of Pharmaceutical Sciences, University of Cincinnati, Cincinnati, Ohio, USA f; Department of Pathology, Fungus Testing Laboratory, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA g; Division of Infectious Diseases, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA h; Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, British Colombia, Canada i; Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts, USA j; Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA k; Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil i; Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil m ; Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Xerém, Rio de Janeiro, Brazil n; Fundação Oswaldo Cruz (Fiocruz), Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Rio de Janeiro, Brazil o; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, New York, USA p; Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, USA q.Submitted by Fabricia Pimenta ([email protected]) on 2018-06-29T19:30:43Z No. of bitstreams: 1 ve_Marcio_Rodrigues_etal_CDTS_2015b.pdf: 2794334 bytes, checksum: b966cb2a47c89038ad9cfde417504848 (MD5)Approved for entry into archive by Fabricia Pimenta ([email protected]) on 2018-07-26T17:44:12Z (GMT) No. of bitstreams: 1 ve_Marcio_Rodrigues_etal_CDTS_2015b.pdf: 2794334 bytes, checksum: b966cb2a47c89038ad9cfde417504848 (MD5)Made available in DSpace on 2018-07-26T17:44:12Z (GMT). No. of bitstreams: 1 ve_Marcio_Rodrigues_etal_CDTS_2015b.pdf: 2794334 bytes, checksum: b966cb2a47c89038ad9cfde417504848 (MD5) Previous issue date: 2015-06-23Fundação Oswaldo Cruz. Centro de Desenvolvimento Tecnológico em Saúde. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. Instituto de Microbiologia Paulo de Góes. Rio de Janeiro, RJ, Brasil.Múltipla - ver notasRecent estimates suggest that >300 million people are afflicted by serious fungal infections worldwide. Current antifungal drugs are static and toxic and/or have a narrow spectrum of activity. Thus, there is an urgent need for the development of new antifungal drugs. The fungal sphingolipid glucosylceramide (GlcCer) is critical in promoting virulence of a variety of human-pathogenic fungi. In this study, we screened a synthetic drug library for compounds that target the synthesis of fungal, but not mammalian, GlcCer and found two compounds [N'-(3-bromo-4-hydroxybenzylidene)-2-methylbenzohydrazide (BHBM) and its derivative, 3-bromo-N'-(3-bromo-4-hydroxybenzylidene) benzohydrazide (D0)] that were highly effective in vitro and in vivo against several pathogenic fungi. BHBM and D0 were well tolerated in animals and are highly synergistic or additive to current antifungals. BHBM and D0 significantly affected fungal cell morphology and resulted in the accumulation of intracellular vesicles. Deep-sequencing analysis of drug-resistant mutants revealed that four protein products, encoded by genes APL5, COS111, MKK1, and STE2, which are involved in vesicular transport and cell cycle progression, are targeted by BHBM