title: Loss of spr1 expression measurable by quantitative RT-PCR in human bronchogenic carcinoma cell lines.
abstract: Expression of the small, proline-rich protein (spr1) squamous differentiation marker was measured in five cultured normal and 12 malignant human bronchial epithelial cell (BEC) populations by quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Whereas spr1 expression was quantifiable and inducible in all five cultured normal cell populations, in all 12 carcinoma cell lines evaluated it was neither quantifiable nor inducible. Primers spanning the entire spr1 coding sequence amplified full-length PCR product from genomic DNA; therefore, large deletions in the coding region were not responsible for the loss of expression measurable by RT-PCR. This is the first molecular genetic marker reported that distinguishes all normal from all carcinoma cell populations evaluated. Because the spr1 protein is a component of the crosslinked envelope that forms during the squamous differentiation process, we hypothesize that the apparent loss of spr1 gene expression disrupts mechanisms for terminal squamous differentiation in the bronchial epithelium, thereby contributing to malignant transformation.
authors.affiliation: Medical College of Ohio, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Toledo, Ohio, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: DeMuth
authors.forename: D A
authors.initials: DA
authors.lastname: Weaver
authors.forename: E L
authors.initials: EL
authors.lastname: Crawford
authors.forename: C M
authors.initials: CM
authors.lastname: Jackson
authors.forename: J C
authors.initials: JC
authors.lastname: Willey
mesh_terms: D001980:Bronchi / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D002283:Carcinoma, Bronchogenic / Q000235:genetics* / Q000473:pathology; D002471:Cell Transformation, Neoplastic; D055233:Cornified Envelope Proline-Rich Proteins; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D015870:Gene Expression; D005786:Gene Expression Regulation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008565:Membrane Proteins; D016133:Polymerase Chain Reaction / Q000379:methods; D011506:Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D055233:Cornified Envelope Proline-Rich Proteins; D008565:Membrane Proteins; D011506:Proteins; D012333:RNA, Messenger