The evolution of single cell-derived colorectal cancer cell lines is dominated by the continued selection of tumor specific genomic imbalances, despite random chromosomal instability

ABSTRACT: Intratumor heterogeneity is a major challenge in cancer treatment. To decipher patterns of chromosomal heterogeneity, we analyzed six colorectal cancer cell lines by multiplex interphase FISH. The mismatch repair deficient cell lines DLD-1 and HCT116 had the most stable copy numbers, whereas aneuploid cell lines displayed a higher degree of instability. We subsequently assessed the clonal evolution of a single cell in two aneuploid cell lines, SW480 and HT-29, which both have near-triploid karyotypes but different degrees of chromosomal instability. The clonal compositions of the single cell-derived daughter cell lines, as assessed by multiplex FISH, differed for HT-29 and SW480. Daughters of HT-29 were stable, clonal, and had little heterogeneity. Daughters of SW480 were more heterogeneous, with the single cell-derived daughter cell lines separating into two distinct populations with different ploidy (hyper-diploid and near-triploid), morphology, gene expression and tumorigenicity. To better understand the evolutionary trajectory for the two SW480 populations, we constructed phylogenetic trees which showed ongoing instability in the daughter cell lines.. When analyzing the evolutionary development over time, most single cell-derived daughter cell lines maintained their major clonal pattern, with the exception of one daughter of SW480 that showed a switch involving a loss of APC. Our meticulous analysis of the clonal evolution and composition of these colorectal cancer models shows that all chromosomes are subject to segregation errors, however, specific net genomic imbalances are maintained.  Karyotype evolution is driven by the necessity to arrive at and maintain a specific plateau of chromosomal copy numbers as the drivers of carcinogenesis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE102647 | GEO | 2018/05/01

REPOSITORIES: GEO