11 research outputs found

    The human HIP gene, overexpressed in primary liver cancer encodes for a C-type carbohydrate binding protein with lactose binding activity

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    AbstractHIP was originally identified as a gene expressed in primary liver cancers, and in normal tissues such as pancreas and small intestine. Based on gene data base homologies, the HIP protein should consist of a signal peptide linked to a single carbohydrate recognition domain. To test this hypothesis HIP and the putative carbohydrate recognition domain encoded by the last 138 C-terminal amino acids, were expressed as glutathione-S -transferase proteins (GST-HIP and GST-HIP-142, respectively). Both recombinant proteins were purified by a single affinity purification step from bacterial lysates and their ability to bind saccharides coupled to trisacryl GF 2000M were tested. Our results show that HIP and HIP-142 proteins bind to lactose, moreover the binding requires divalent cations. Thus the HIP protein is a lactose-binding lectin with the characteristics of a C-type carbohydrate recognition domain of 138 amino acids in the C-terminal region

    New insights into diagnosis and therapeutic options for proliferative hepatoblastoma

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    International audienceSurgery and cisplatin-based treatment of hepatoblastoma (HB) currently guarantee the survival of 70-80% of patients. However, some important challenges remain in diagnosing high risk tumors and identifying relevant targetable pathways offering new therapeutic avenues. Previously, two molecular subclasses of hepatoblastoma tumors have been described, namely C1 and C2; C2 being the subgroup with the poorest prognosis, a more advanced tumor stage and the worst overall survival rate. An associated 16-gene signature to discriminate the two tumoral subgroups was proposed but it has not been transferred into clinical routine. To address these issues we performed RNA sequencing of 25 tumors and matched normal liver samples from patients. The transcript profiling separated HB into three distinct subgroups named C1, C2A and C2B, identifiable by a concise four-gene signature: HSD17B6, ITGA6, TOP2A and VIM, with TOP2A being characteristic for the proliferative C2A tumors. Differential expression of these genes was confirmed by RT-qPCR on an expanded cohort and by immunohistochemistry. We also revealed significant overexpression of genes involved in Fanconi Anemia (FA) pathway in the C2A subgroup. We then investigated the ability of several described FA inhibitors to block growth of HB cells in vitro and in vivo. We demonstrated that bortezomib, an FDA-approved proteasome inhibitor, strongly impairs the proliferation and survival of HB cell lines in vitro, blocks FA pathway associated double-strand DNA repair and significantly impedes HB growth in vivo. In conclusion, the highly proliferating C2A subtype is characterized by TOP2A gene up-regulation and FA pathway activation and HB therapeutic arsenal could include Bortezomib for the treatment of patients with the most aggressive tumors. This article is protected by copyright. All rights reserved
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