Keratinocyte transglutaminase expression varies in squamous cell carcinomas.
Type I transglutaminase (TGase I, keratinocyte or particulate transglutaminase) is a 92-kilodalton (kDa) protein expressed in abundance in cultured keratinocytes and in the hyperproliferative skin disorder psoriasis. To determine the expression of TGase I protein and mRNA, we studied tissue and established squamous carcinoma lines derived from different sources. Immunohistochemistry and Western blotting were used to detect TGase I protein with the B.C1 mouse monoclonal antibody. Only well-differentiated, skin-derived squamous carcinomas stained for TGase I. However, a precocious pattern of expression was seen overlying less-differentiated tumors. Compared to cultured human keratinocytes, squamous cell carcinoma (SCC) had many times less to 7.8 times more TGase I protein, greatest in the two most differentiated tumor lines 14-83 and ME-180. TGase I mRNA levels ranged from 0.010 to 0.00004 pg/microgram total RNA by reverse transcriptase-polymerase chain reaction using an internal standard. Protein expression correlated with mRNA levels in most SCC lines. When a human TGase I promoter was isolated and used to study genomic DNA, SCC1-83 was shown to have unique restriction enzyme fragments, including one indicative of methylation differences, also present within DNA from the KB line. These studies suggest that transcriptional control of TGase I gene expression in squamous carcinomas may be influenced both by cis elements in the promoter and by the degree of tumor squamous differentiation.
Duvic
M
M
Department of Dermatology, University of Texas Medical School at Houston 77030.
Nelson
D C
DC
Annarella
M
M
Cho
M
M
Esgleyes-Ribot
T
T
Remenyik
E
E
Ulmer
R
R
Rapini
R P
RP
Sacks
P G
PG
Clayman
G L
GL
D000483:Alleles; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D007624:KB Cells; D015603:Keratinocytes / Q000201:enzymology*; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000032:analysis; D012878:Skin Neoplasms / Q000201:enzymology* / Q000235:genetics; D011503:Transglutaminases / Q000032:analysis* / Q000235:genetics
D012333:RNA, Messenger; D011503:Transglutaminases