Identification of a novel metastasis-suppressor region on human chromosome 12.
There is a critical need for markers that can be used to predict accurately the malignant potential of histological prostate cancers (J. T. Isaacs. Am. J. Pathol., 150: 1511-1521, 1997). Metastasis-suppressor genes are attractive candidates for marker development because, by definition, their loss should be associated with the acquisition of metastatic ability. In an effort to identify such genes, a single copy of human chromosome 12, tagged with the neomycin resistance gene, was introduced into highly metastatic Dunning AT6.1 prostate cancer cells by microcell-mediated chromosomal transfer. Thirty-two AT6.1-12 clonal cell lines were established and the region(s) of chromosome 12 retained was determined by sequence tagged site-based PCR analysis. Representative AT6.1-12 clones containing overlapping regions of chromosome 12 were characterized cytogenetically and were shown to have a normal complement of parental AT6.1 rat chromosomes. Fluorescence in situ hybridization, performed on representative AT6.1-12 hybrids, demonstrated a single human chromosome 12-specific signal. The metastatic ability of six representative clones was tested in immunodeficient mice. All of the AT6.1-12 clones showed the same in vivo growth rates as the control AT6.1-neo cells. Clonal cell lines that contained a conserved approximately 70-cM portion of chromosome 12 (e.g., AT6.1-12-8, -8-1, and -8-3), showed a >30-fold suppression in the number of macroscopic surface lung metastases. Mice that received injections of these cells developed a mean number 4 lung metastases whereas mice that received injections of other AT6.1-12 hybrids (lacking the approximately 70-cM region) or AT6.1-neo control cells, developed a mean number of 140 metastases. Interestingly, histological examination of the lungs of the mice that received injections of AT6.1-12-8 cells showed essentially no microscopic metastases. These findings suggest that a gene(s) encoded by the approximately 70-cM portion of human chromosome 12 suppresses an early step in the metastatic cascade.
Luu
H H
HH
Department of Surgery, University of Chicago, Illinois, USA.
Zagaja
G P
GP
Dubauskas
Z
Z
Chen
S L
SL
Smith
R C
RC
Watabe
K
K
Ichikawa
Y
Y
Ichikawa
T
T
Davis
E M
EM
Le Beau
M M
MM
Rinker-Schaeffer
C W
CW
D000818:Animals; D000903:Antibiotics, Antineoplastic; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D051379:Mice; D016513:Mice, SCID; D009355:Neomycin; D009362:Neoplasm Metastasis / Q000235:genetics; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D051381:Rats; D014407:Tumor Cells, Cultured
D000903:Antibiotics, Antineoplastic; D009355:Neomycin