The RS4;11 cell line as a model for leukaemia with t(4;11)(q21;q23): Revised characterisation of cytogenetic features

Abstract

Background: Haematological malignancies harbouring rearrangements of the KMT2A gene represent a unique subtype of leukaemia, with biphenotypic clinical manifestations, a rapid and aggressive onset, and a generally poor prognosis. Chromosomal translocations involving KMT2A often cause the formation of oncogenic fusion genes, such as the most common translocation t(4;11)(q21;q23) producing the KMT2A-AFF1 chimera.Aim: The aim of this study was to confirm and review the cytogenetic and molecular features of the KMT2A-rearranged RS4;11 cell line and put those in context with other reports of cell lines also harbouring a t(4;11) rearrangement. Methods and Results:The main chromosomal rearrangements t(4;11)(q21;q23) and i(7q), described when the cell line was first established, were confirmed by fluorescence in situ hybridisation (FISH) and 24-colour karyotyping by M-FISH. Additional cytogenetic abnormalities were investigated by further FISH experiments, including the presence of trisomy 18 as a clonal abnormality and the discovery of one chromosome 8 being an i(8q), which indicates a duplication of the oncogene MYC. A homozygous deletion of 9p21 containing the tumour-suppressor genes CDKN2A and CDKN2B was also revealed by FISH. The production of the fusion transcript KMT2A-AFF1 arising from the der(11)t(4;11) was confirmed by RT-PCR, but sequencing of the amplified fragment revealed the presence of multiple isoforms. Two transcript variants, resulting from alternative splicing, were identified differing in one glutamine residue in the translated protein. Conclusion:As karyotype evolution is a common issue in cell lines, we highlight the need to monitor cell lines in order to re-confirm their characteristics over time. We also reviewed the literature to provide a comparison of key features of several cell lines harbouring a t(4;11). This would guide scientists in selecting the most suitable research model for this particular type of KMT2A-leukaemia.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

MYC: a multipurpose oncogene with prognostic and therapeutic implications in blood malignancies

“…It has been shown that t(8;14) is less frequent in cases with wild-type CDKN2 [ 473 ]. Furthermore, RS4;11 (KMT2A-AFF1), a B-cell leukemic cell line containing isochromosome i(8q), shows a duplicated MYC gene [ 474 ]. The KMT2A-AFF1 rearrangement mostly participates in the leukemic progression as a second hit, and B-ALL patients with this fusion protein possess a significantly promoted MYC gene expression in comparison to patients with AML [ 475 , 476 ].…”

Cup-like nuclei in adult B-cell acute lymphoblastic leukemia with the translocation (4;11)(q21;q23)

“…reported on a patient with therapy-related ALL who received a topoisomerase II inhibitor for induction chemotherapy. A higher frequency of MLL gene rearrangements, especially t(4;11), was observed in cases of therapy-related ALL compared to therapy-related AML.A recent novel study concludes that the RS4;11 cell line serves as an appropriate in vitro model for studying leukemia with t(4;11), potentially aiding in advancing research and achieving breakthroughs in understanding the relationship between CLN and chromosomal aberrations such as t(4;11) [ 10 ].…”

Fmoc-FF hydrogels and nanogels for improved and selective delivery of dexamethasone in leukemic cells and diagnostic applications

“…The human lymphoblastic leukemia cell line RS4;11 was obtained from the IRCCS SYNLAB SDN Biobank 31 . Cells were detained in IMDM medium, supplemented with 10% FBS, 10 mM Glutamine and the addition of 1 × Penicillin–Streptomycin solution (Lonza) and kept in a humidified incubator at 37 °C and 5% CO 2 .…”