Flow cytometric and karyotypic analyses of androgen-responsive and androgen-independent Shionogi mouse mammary tumours.
The androgen-responsive (AR) Shionogi mouse mammary carcinoma is a heterogeneous tumour composed of AR and androgen-independent (AI) cells. We characterized the cells of the AR tumour and those of its AI derivative by flow cytometric analysis of DNA content and karyotypic analysis of metaphase spreads. Both tumours had diploid and near tetraploid populations of cells. However, the AR and AI malignant cells of these tumours both appeared to be polyploid. A decrease in the polyploid population of the AR tumour accompanied tumour regression following castration, but this population was restored when tumour growth resumed. Although karyotypic analysis of metaphase spreads showed wide variations in chromosome numbers among the polyploid population, the range, 55-88 chromosomes, was found in both AR and AI tumours. In addition, the same chromosome anomalies, including a marker chromosome, were identified in both tumours. Since the AR and AI malignant cells could not be distinguished on the basis of their DNA content or karyotype, the cell types may not represent genetically distinct populations of cells. The AR cells may undergo alterations in gene expression in adapting to their androgen-free environment.
Department of Anatomy, University of British Columbia, Vancouver, Canada.
J T
JT
Emerman
D K
DK
Kalousek
D000728:Androgens / Q000378:metabolism*; D000818:Animals; D002469:Cell Separation; D004273:DNA, Neoplasm / Q000235:genetics*; D005434:Flow Cytometry; D007621:Karyotyping; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D011003:Ploidies
D000728:Androgens; D004273:DNA, Neoplasm