Molecular cytogenetic studies of a serially transplanted primary prostatic carcinoma xenograft (CWR22) and four relapsed tumors.

Kochera M, Depinet T W, Pretlow T P, Giaconia J M, Edgehouse N L, Pretlow T G, Schwartz S

Department of Genetics and Center for Human Genetics, Case Western Reserve University School of Medicine and University Hospitals of Cleveland, Cleveland, Ohio, USA.

Prostate. 1999 Sep 15;41(1):7-11. doi: 10.1002/(sici)1097-0045(19990915)41:1<7::aid-pros2>3.0.co;2-1.

BACKGROUND

Established cell lines or xenografts from prostatic carcinoma have been infrequently studied cytogenetically. CWR22 and CWR22-R are xenografts that are unique in offering one strongly androgen-dependent and several relapsed strains of a human prostate cancer that can be investigated in the laboratory. We report on the cytogenetic characterization of the hormone-dependent CWR22, and the relapsed CWR22-R serially transplanted xenografts, in our laboratory.

METHODS

We utilized a suspension harvest of the xenograft tissue to optimize our yield for metaphase chromosome studies and analyzed the hormone-dependent CWR22 and four relapsed CWR22-R xenografts. These studies were accomplished using standard G-banded analysis and fluorescence in situ hybridization (FISH). A variety of DNA probes including alpha-satellite DNA probes, and chromosomal libraries, were utilized for the FISH analysis.

RESULTS

Utilizing both standard cytogenetic analysis and FISH studies we have more precisely defined the CWR22 xenograft: 49,XY,+i(1)(q10),-2, der(4)t(2;4)(p21;q33), +7,+8,+12[7]/50,XY,idem, +der(2)t(2;4)(p21;q33)del(2)(q13q33)[13]. Four relapsed xenografts, CWR22R-2152, CWR22R-2524, CWR22R-2274, and CWR22R-2272 were also studied. Each of these lines demonstrated a different karyotype.

CONCLUSIONS

The CWR22 karyotype offers the simplest reported karyotype for a prostate cancer tissue culture cell line or xenograft; this makes CWR22 an attractive candidate for studies of genetic changes associated with the relapse of prostate cancer treated with androgen withdrawal. Four separate, serially transplanted, relapsed CWR22-R xenografts were detected, each with a separate karyotype.