Comprehensive measurement of chromosomal instability in cancer cells: combination of fluorescence in situ hybridization and cytokinesis-block micronucleus assay.
Most tumors show abnormal karyotypes involving either chromosome rearrangements and/or aneuploidies. The aim of our study is to measure the rate of both structural and numerical chromosome instability in two colorectal cancer cell lines: HCT116, and SW480 and its single subclones. To determine structural instability, we measured the nonclonal chromosome alterations of the last cell division by means of multicolor-fluorescence in situ hybridization (FISH). To quantify numerical instability, we used centromere-specific DNA probes to simultaneously detect chromosome loss and nondisjunctional events in binucleated cells obtained by cytokinesis-block micronucleus assay (CBMN). After clonal episodes, the structural chromosome instability rate increased significantly, confirming the large contribution of structural rearrangements to the heterogeneity of cancer cells. On the other hand, the aneuploidy rate was high and conserved in both the parental SW480 cell line and its subclones. The ability to differentiate chromosome loss and nondisjunction by the CBMN assay allowed us to conclude that no significant differences were detected among these events. Analysis of nucleoplasmic bridges, micronuclei, and nuclear blebs also demonstrated the differences among the structural instability rates of the parental cell line and its subclones. Overall, our results demonstrate the prevalence of structural over numerical chromosome instability in the subclones when comparing them with their parental cell line, confirming the contribution of ongoing chromosomal reorganizations in the generation of tumor cell heterogeneity.
Camps
Jordi
J
Departament de Biologia Cellular, Fisiologia i Immunologia and Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Spain. jordi.camps@uab.es
Ponsa
Immaculada
I
Ribas
Maria
M
Prat
Esther
E
Egozcue
Josep
J
Peinado
Miguel A
MA
Miró
Rosa
R
D000782:Aneuploidy; D045744:Cell Line, Tumor; D002503:Centromere / Q000235:genetics; D043171:Chromosomal Instability; D015179:Colorectal Neoplasms / Q000235:genetics; D048749:Cytokinesis; D015342:DNA Probes; D015321:Gene Rearrangement; D045325:HCT116 Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015162:Micronucleus Tests; D009369:Neoplasms / Q000235:genetics*; D009630:Nondisjunction, Genetic
D015342:DNA Probes