title: Proteoglycan changes in carcinogen (4NQO)-treated rat tongue mucosa.
abstract: The purpose of this study was to undertake preliminary analyses of the extracellular proteoglycans in carcinogen [4-nitroquinoline N-oxide (4NQO)]-treated rat tongue mucosa. Experimental rats were exposed to twice-weekly applications of 4NQO in propylene glycol for six months, after which the animals were killed. Control and 4NQO-treated tissues were subjected to sequential aqueous extractions of proteoglycans under associative and dissociative conditions, followed by alkaline cleavage of protein-glycosaminoglycan linkages to yield a glycosaminoglycan residue. Tissues subjected to 4NQO applications contained smaller proportions of proteoglycans which were readily soluble under associative and dissociative conditions. Proportionately more proteoglycan remained strongly associated with other intercellular tissue components, being released only by alkaline cleavage. These biochemical alterations in preinvasive 4NQO-treated epithelium and connective tissues, together with an observed associated change in water retention by the connective tissue, occurred prior to actual neoplastic invasion and suggest differences in macromolecular conformation and orderliness. We hypothesize that these changes are related to the phenomenon of neoplastic epithelial invasion.
authors.affiliation: Department of Dentistry, University of Adelaide, South Australia.
authors.forename: D F
authors.initials: DF
authors.lastname: Wilson
authors.forename: A
authors.initials: A
authors.lastname: Vreugdenburg
authors.forename: O W
authors.initials: OW
authors.lastname: Wiebkin
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000008:administration & dosage / Q000009:adverse effects*; D000287:Administration, Topical; D000818:Animals; D001834:Body Water / Q000737:chemistry / Q000187:drug effects; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology; D003238:Connective Tissue / Q000737:chemistry / Q000187:drug effects / Q000473:pathology; D004848:Epithelium / Q000737:chemistry / Q000187:drug effects / Q000473:pathology; D016326:Extracellular Matrix Proteins / Q000032:analysis / Q000187:drug effects*; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis; D006965:Hyperplasia; D009061:Mouth Mucosa / Q000737:chemistry / Q000187:drug effects / Q000473:pathology; D009361:Neoplasm Invasiveness; D011230:Precancerous Conditions / Q000737:chemistry / Q000473:pathology; D011509:Proteoglycans / Q000032:analysis / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D012995:Solubility; D014059:Tongue / Q000737:chemistry / Q000187:drug effects* / Q000473:pathology; D014062:Tongue Neoplasms / Q000737:chemistry / Q000473:pathology
chemical_list: D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D011509:Proteoglycans; D015112:4-Nitroquinoline-1-oxide