Cytogenetic analysis is a crucial component in quality control (QC) testing in order to establish the genomic stability of cells. Chromosomal abnormalities are known to arise rather frequently in culturing cells, providing a growth advantage. Particular importance must be given in cell-based therapies, and more specifically the scale-up of pluripotent stem cells, such as human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs).1 Furthermore, in hiPSCs the reprogramming process may lead to genomic aberrations besides time in culture and passaging that alone may foster the accumulation and selection of novel genomic alterations.2-5 Hence, a “genomic check-up” should be seriously considered as a routinely QC for pluripotent cell cultures. The use of an abnormal cell line often results in a waste of time and resources, thus the control of the genomic stability of cell lines may prevent negative outcomes and ensure the validity of the work.

The Cytogenetic Service should be used:

–  when a cell line is established/derived;

–  to monitor the genomic stability of a cell line (routine QC testing);

–  at the beginning and conclusion of an experiment;

–  for publication-quality karyotype;

–  for cell banking;

–  when a cell culture displays unusual growth properties.

References:

1. Laurent, L. C. et al. Dynamic changes in the copy number of pluripotency and cell proliferation genes in human ESCs and iPSCs during reprogramming and time in culture. Cell Stem Cell 8, 106-118, doi: 10.1016/j.stem.2010.12.003 (2011).
2. Taapken, S. M. et al. Karyotypic abnormalities in human induced pluripotent stem cells and embryonic stem cells. Nat Biotechnol 29, 313-314, doi: 10.1038/nbt.1835(2011).
3. Blasco, M. A., Serrano, M. & Fernandez-Capetillo, O. Genomic instability in iPS: time for a break. EMBO J 30, 991-993, doi: 10.1038/emboj.2011.50 (2011).
4. Liang, Y. et al. The propensity for tumorigenesis in human induced pluripotent stem cells is related with genomic instability. Chin J Cancer 32, 205-212, doi:10.5732/cjc.012.10065 (2013).
5. Bai, Q. et al. Temporal Analysis of Genome Alterations Induced by Single-Cell Passaging in Human Embryonic Stem Cells. Stem Cells Dev, doi: 10.1089/scd.2014.0292(2014).
 
ISENET S.r.l. routine genomic stability analysis are:
 
1. conventional karyotyping (Q-banding) on actively growing cells;2. array Comparative Genomic Hybridization (aCGH) with a resolution down to 50kb (or less, depending on the array format).