False leukemia–lymphoma cell lines: an update on over 500 cell lines

Abstract

Human leukemia-lymphoma (LL) cell lines represent an extremely important resource for research in a variety of fields and disciplines. As the cell lines are used as in vitro model systems in lieu of primary cell material, it is crucial that the cells in the culture flasks faithfully correspond to the purported objects of study. Obviously, proper authentication of cell line derivation and precise characterization are indispensable requirements to use as model systems. A number of studies has shown an unacceptable level of LL cell lines to be false. We present here the results of authenticating a comprehensively large sample (n = 550) of LL cell lines mainly by DNA fingerprinting and cytogenetic evaluation. Surprisingly, nearidentical incidences (ca 15%) of false cell lines were observed among cell lines obtained directly from original investigators (59/395: 14.9%) and from secondary sources (23/155: 14.8%) implying that most cross-contamination is perpetrated by originators, presumably during establishment. By comparing our data with those published, we were further able to subclassify the false cell lines as (1) virtual: cross-contaminated with and unretrievably overgrown by other cell lines during initiation, never enjoying independent existence; (2) misidentified: crosscontaminated subsequent to establishment so that an original prototype may still exist; or (3) misclassified: unwittingly established from an unintended (often normal) cell type. Prolific classic leukemia cell lines were found to account for the majority of cross-contaminations, eg CCRF-CEM, HL-60, JUR-KAT, K-562 and U-937. We discuss the impact of cross-contaminations on scientific research, the reluctance of scientists to address the problem, and consider possible solutions. These findings provide a rationale for mandating the procurement of reputably sourced LL cell lines and their regular authentication thereafter.

Frequent loss of RAF kinase inhibitor protein expression in acute myeloid leukemia

“…1,2 Cell lines were obtained from the German National Resource Center for Biological Material (DSMZ, Braunschweig, Germany) and regularly screened by variable number of tandem repeat profiling for authenticity. 20 Normal CD34 þ HSPC specimens were isolated from leukapheresis harvests of six patients with non-myeloid malignancies and four umbilical cord blood samples. The study was approved by the institutional review board of the Medical University of Graz, Graz, Austria, and informed consent was obtained from all individuals.…”

Authenticity and drug resistance in a panel of acute lymphoblastic leukaemia cell lines

“…Investigation of resistance mechanisms and evaluation of novel drug-leads invariably requires the use of immortalised cell lines, but the extent to which these cells retain features of the original disease in vivo is a matter of some debate (Kamb, 2005), a problem exemplified by the typically high growth rates of continuous cultures (Masters, 2000). Added to this is concern over the alarming frequency with which cultures have been found retrospectively to be infected with mycoplasma or cross-contaminated with other cell lines (so-called 'false' lines) (Masters, 2000;Drexler et al, 2003). This has led to repeated calls for the extensive characterisation and validation of authenticity of such cell lines (Drexler and Matsuo, 1999;Masters et al, 2001;Drexler et al, 2002Drexler et al, , 2003.…”

“…Added to this is concern over the alarming frequency with which cultures have been found retrospectively to be infected with mycoplasma or cross-contaminated with other cell lines (so-called 'false' lines) (Masters, 2000;Drexler et al, 2003). This has led to repeated calls for the extensive characterisation and validation of authenticity of such cell lines (Drexler and Matsuo, 1999;Masters et al, 2001;Drexler et al, 2002Drexler et al, , 2003.…”

Cytogenetic harvesting of commonly used tumor cell lines

“…With G-banding alone, it is possible to detect, if not fully characterize, most chromosome rearrangements present in cell lines carrying up to approximately half a dozen separate changes; i.e., it is sufficient for confirming cell line identity. The utility of Gbanding in detecting cell line cross-contamination is illustrated in Figure 3, which shows CCRF-CEM derived from pediatric T-acute lymphoblastic leukemia (T-ALL) and its tetraploid derivate COLE, mistakenly published as a Hodgkin lymphoma cell line 3,14 .…”