title: Selective expression and functional characteristics of three mammalian hyaluronan synthases in oncogenic malignant transformation.
abstract: Malignant transformation of fibroblasts and epithelial cells is often accompanied by increased hyaluronan production and accumulation. Despite recent progress in the study of hyaluronan biosynthesis, the mechanisms underlying the transformation-induced overproduction of hyaluronan have not been elucidated. Here we report that activity and transcriptional levels of hyaluronan synthase (HAS) significantly increased after oncogenic malignant transformation of a rat 3Y1 fibroblast cell line. Of three HAS isoforms (HAS1, HAS2, and HAS3), only HAS2 gene expression was increased in the v-Ha-ras transformed 3Y1 cells, which show less malignancy. In contrast, both HAS1 and HAS2 expressions were elevated in the highly malignant cells transformed with v-src and/or v-fos. To assess the contribution of HAS expression to the oncogenic malignant transformation, we established stable cell transfectants expressing sense and antisense HAS genes. Antisense suppression of the HAS2 expression significantly decreased hyaluronan production in the cells transformed by the oncogenic v-Ha-ras and eventually led to a reduction in tumorigenicity in the rat peritoneum. The introduction of the HAS1 and HAS2 genes promoted the growth of subcutaneous tumors in a manner dependent on the levels of hyaluronan synthesis. Significant growth promotion was observed within a wide range of HAS1 expression. In contrast, the growth stimulation was only seen within a narrow range of HAS2 expression, and high levels of HAS2 expression even inhibited tumor growth. These results suggest that proper regulation of the expression of each HAS isoform is required for optimal malignant transformation and tumor growth.
authors.affiliation: Institute for Molecular Science of Medicine, Aichi Medical University, Nagakute, Aichi 480-1195, Japan. itano@amugw.aichi-med-u.ac.jp
authors.forename: Naoki
authors.initials: N
authors.lastname: Itano
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sawai
authors.forename: Fukiko
authors.initials: F
authors.lastname: Atsumi
authors.forename: Osamu
authors.initials: O
authors.lastname: Miyaishi
authors.forename: Shun'ichiro
authors.initials: S
authors.lastname: Taniguchi
authors.forename: Reiji
authors.initials: R
authors.lastname: Kannagi
authors.forename: Michinari
authors.initials: M
authors.lastname: Hamaguchi
authors.forename: Koji
authors.initials: K
authors.lastname: Kimata
mesh_terms: D000818:Animals; D001483:Base Sequence; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D014453:Glucuronosyltransferase / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D009374:Neoplasms, Experimental / Q000209:etiology / Q000473:pathology; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014162:Transfection; D014166:Transferases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015854:Up-Regulation
chemical_list: D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D006820:Hyaluronic Acid; D014166:Transferases; D014453:Glucuronosyltransferase; C491356:Has3 protein, mouse; C491355:Has3 protein, rat; D000076002:Hyaluronan Synthases