Expression of cytokeratin-19 as a marker of neoplastic progression of human prostate epithelial cells.
BACKGROUND
Our earlier studies demonstrated neoplastic transformation of SV40-immortalized neonatal human prostate epithelial cells (267B1) by fractionated doses of ionizing radiation or by introduction of v-ki-ras oncogene. X-ray-treated 267B1 cells represent three different stages of neoplastic progression: nontumorigenic F3-SAC cells that acquired morphological changes and anchorage independence when treated with 2 x 2 Gy of X-rays; malignantly transformed 267B1-XR and 267B1-SXR cells that received 2-Gy doses to a total of 30 Gy. We also reported alterations in cell size, morphology, actin stress fibers, and levels of actin-binding proteins in these transformed human prostate cells.


METHODS
We analyzed intermediate filament-nuclear matrix (IF-NM) protein expression in the various 267B1 cells as a consequence of neoplastic progression by two-dimensional gel electrophoresis and immunofluorescence.


RESULTS
Our present study revealed that the 267B1 cells experienced progressive changes in their intermediate filament protein composition during the process of neoplastic conversion, achieved either by X-rays or by ras-oncogene. In particular, we observed a stepwise downregulation of cytokeratin-19 in these in vitro transformed 267B1 cells.


CONCLUSIONS
Our data suggest that loss of expression of cytokeratin-19 accompanied the morphological alterations associated with in vitro neoplastic transformation of SV40-immortalized prostate epithelial cells.
Prasad
S
S
Department of Radiation Medicine, Georgetown University Medical Center, Washington, DC 20007-2197, USA. prasads@gunet.georgetown.edu
Thraves
P
P
Dritschilo
A
A
Kuettel
M
M
D014408:Biomarkers, Tumor / Q000096:biosynthesis*; D002471:Cell Transformation, Neoplastic; D018450:Disease Progression; D004847:Epithelial Cells / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D007381:Intermediate Filament Proteins / Q000032:analysis; D007633:Keratins / Q000096:biosynthesis*; D008297:Male; D015530:Nuclear Matrix / Q000737:chemistry; D009687:Nuclear Proteins / Q000032:analysis; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000473:pathology; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D007381:Intermediate Filament Proteins; D009687:Nuclear Proteins; D007633:Keratins