S. Prasad et al., EXPRESSION OF CYTOKERATIN-19 AS A MARKER OF NEOPLASTIC PROGRESSION OFHUMAN PROSTATE EPITHELIAL-CELLS, The Prostate, 35(3), 1998, pp. 203-211
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-k
i-ras oncogene. X-ray-treated 267B1 cells represent three different st
ages of neoplastic progression: nontumorigenic F3-SAC cells that acqui
red morphological changes and anchorage independence when treated with
2 x 2 Gy of X-rays; malignantly transformed 267B1-XR and 267B1-SXR ce
lls that received 2-Gy doses to a total of 30 Gy. We also reported alt
erations in cell size, morphology, actin stress fibers, and levels of
actin-binding proteins in these transformed human prostate cells. METH
ODS. We analyzed intermediate filament-nuclear matrix (IF-NM) protein
expression in the various 267B1 cells as a consequence of neoplastic p
rogression by two-dimensional gel electrophoresis and immunofluorescen
ce. RESULTS. Our present study revealed that the 267B1 cells experienc
ed progressive changes in their intermediate filament protein composit
ion during the process of neoplastic conversion, achieved either by X-
rays or by ras-oncogene. In particular, we observed a stepwise downreg
ulation of cytokeratin-19 in these in vitro transformed 267B1 cells. C
ONCLUSIONS. Our data suggest that loss of expression of cytokeratin-19
accompanied the morphological alterations associated with in vitro ne
oplastic transformation of SV40-immortalized prostate epithelial cells
. (C) 1998 Wiley-Liss, Inc.