Comparison of Established Cell Lines at Different Passages by Karyotype and Comparative Genomic Hybridization

TLDR

The study compared MCF‑7 and Ishikawa cell lines obtained from a repository and a laboratory, using comparative genomic hybridization by co‑hybridizing each line to normal metaphases. The karyotype and CGH analyses revealed that MCF‑7 lines differed by up to 83 chromosomes and structural abnormalities linked to passage number, while Ishikawa lines had up to 60 chromosomes with a shared missing X, and the two Ishikawa cultures were not derived from the same tumor, underscoring the need for periodic evaluation of cell line origin.

Abstract

Two established cancer cell lines, MCF-7 and Ishikawa, were both obtained directly from a cell repository and through another laboratory. The karyotypes from the two MCF-7 cell lines had up to 83 chromosomes and similarities for chromosomal gain and structural abnormalities. The two Ishikawa cell lines had up to 60 chromosomes with only a missing X as the common chromosome abnormality. CGH studies were performed by co-hybridizing the two Ishikawa or MCF-7 cell lines to normal metaphases. The differences seen between the two MCF-7 cell cultures reflect changes due to passage number and culture conditions. For Ishikawa, DNA polymorphic data and mutation studies suggest that the two cell lines are not derived from the same established tumor cell line. Our study shows the utilization of CGH in comparing cell lines originating from the same specimen. Our study also demonstrates the necessity for periodically evaluating cell lines to confirm their origin.