The spliceosome as a target of novel antitumour drugs.
ABSTRACT Several bacterial fermentation products and their synthetic derivatives display antitumour activities and bind tightly to components of the spliceosome, which is the complex molecular machinery involved in the removal of introns from mRNA precursors in eukaryotic cells. The drugs alter gene expression, including alternative splicing, of genes that are important for cancer progression. A flurry of recent reports has revealed that genes encoding splicing factors, including the drug target splicing factor 3B subunit 1 (SF3B1), are among the most highly mutated in various haematological malignancies such as chronic lymphocytic leukaemia and myelodysplastic syndromes. These observations highlight the role of splicing factors in cancer and suggest that an understanding of the molecular effects of drugs targeting these proteins could open new perspectives for studies of the spliceosome and its role in cancer progression, and for the development of novel antitumour therapies.
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ABSTRACT: RNA splicing is a fundamental process for protein synthesis. Recent studies have reported that drugs that inhibit splicing have cytotoxic effects on various tumor cell lines. In this report, we demonstrate that depletion of SNW1, a component of the spliceosome, induces apoptosis in breast cancer cells. Proteomics and biochemical analyses revealed that SNW1 directly associates with other spliceosome components, including EFTUD2 (Snu114) and SNRNP200 (Brr2). The SKIP region of SNW1 interacted with the N-terminus of EFTUD2 as well as two independent regions in the C-terminus of SNRNP200. Similar to SNW1 depletion, knockdown of EFTUD2 increased the numbers of apoptotic cells. Furthermore, we demonstrate that exogenous expression of either the SKIP region of SNW1 or the N-terminus region of EFTUD2 significantly promoted cellular apoptosis. Our results suggest that the inhibition of SNW1 or its associating proteins may be a novel therapeutic strategy for cancer treatment. © 2014 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.Cancer Medicine 12/2014; 4(2). DOI:10.1002/cam4.366
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ABSTRACT: Myelodysplastic syndromes (MDS) are a group of clonal disorders arising from hematopoietic stem cells generally characterized by inefficient hematopoiesis, dysplasia in one or more myeloid cell lineages, and variable degrees of cytopenias. Most MDS patients are diagnosed in their late 60s to early 70s. The estimated incidence of MDS in the United States and in Europe are 4.3 and 1.8 per 100,000 individuals per year, respectively with lower rates reported in some Asian countries and less well estimated in other parts of the world. Evolution to acute myeloid leukemia can occur in 10-15% of MDS patients. Three drugs are currently approved for the treatment of patients with MDS: immunomodulatory agents (lenalidomide), and hypomethylating therapy [HMT (decitabine and 5-azacytidine)]. All patients will eventually lose their response to therapy, and the survival outcome of MDS patients is poor (median survival of 4.5 months) especially for patients who fail (refractory/relapsed) HMT. The only potential curative treatment for MDS is hematopoietic cell transplantation. Genomic/chromosomal instability and various mechanisms contribute to the pathogenesis and prognosis of the disease. High throughput genetic technologies like single nucleotide polymorphism array analysis and next generation sequencing technologies have uncovered novel genetic alterations and increased our knowledge of MDS pathogenesis. We will review various genetic and non-genetic causes that are involved in the pathogenesis of MDS.12/2014; 49(4):216-27. DOI:10.5045/br.2014.49.4.216
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ABSTRACT: Background:We showed previously that breast carcinoma amplified sequence 2 (BCAS2) functions as a negative regulator of p53. We also found that BCAS2 is a potential AR-associated protein. AR is essential for the growth and survival of prostate carcinoma. Therefore we characterised the correlation between BCAS2 and AR.Methods:Protein interactions were examined by GST pull-down assay and co-immunoprecipitation. Clinical prostate cancer (PCa) specimens were evaluated by immunohistochemical assay. AR transcriptional activity and LNCaP cell growth were assessed by luciferase assay and MTT assay, respectively.Results:BCAS2 expression was significantly increased in PCa. BCAS2 stabilised AR protein through both hormone-dependent and -independent manners. There are at least two mechanisms for BCAS2-mediated AR protein upregulation: One is p53-dependent. The p53 is suppressed by BCAS2 that results in increasing AR mRNA and protein expression. The other is via p53-independent inhibition of proteasome degradation. As BCAS2 can form a complex with AR and HSP90, it may function with HSP90 to stabilise AR protein from being degraded by proteasome.Conclusions:In this study, we show that BCAS2 is a novel AR-interacting protein and characterise the correlation between BCAS2 and PCa. Thus we propose that BCAS2 could be a diagnostic marker and therapeutic target for PCa.British Journal of Cancer advance online publication, 2 December 2014; doi:10.1038/bjc.2014.603 www.bjcancer.com.British Journal of Cancer 12/2014; DOI:10.1038/bjc.2014.603 · 4.82 Impact Factor