Abstract: While working with G418-resistant stably transfected cells, we realized the neomycin resistance gene
(NeoR), which encodes the aminoglycoside-39-phosphotransferase-IIa [APH(39)-IIa], also confers resistance to the
nucleoside analog fludarabine. Fludarabine is a cytostatic drug widely used in the treatment of hematologic and
solid tumors as well as in the conditioning of patients before transplantation of hematopoietic progenitors. We
present evidence thatNeoR-transfected cells do not incorporate fludarabine, thus avoidingDNAdamage caused by
the drug, evidenced by a lack of FANCD2 monoubiquitination and impaired apoptosis. A screening of other
nucleoside analogs revealed that APH(39)-IIa only protects against ATP purine analogs. Moreover, APH(39)-IIa
ATPase activity is inhibited by fludarabine monophosphate, suggesting that APH(39)-IIa blocks fludarabine incorporation
intoDNAby dephosphorylating its active fludarabine triphosphate form. Furthermore, overexpression
of the catalytic subunit of the eukaryotic kinase PKA,which is structurally related to APHs, also provides resistance
to fludarabine, anticipating its putative utility as a response marker to the drug. Our results preclude the use of Neo
marker plasmids in the study of purine analogs and unveils a new resistance mechanism against these
chemotherapeuticals.?S´anchez-Carrera, D., Bravo-Navas, S., Cabez´on, E., Arechaga, I., Cabezas, M., Y´añez, L.,
Pipa´on, C. Fludarabine resistance mediated by aminoglycoside-39-phosphotransferase-IIa and the structurally related
eukaryotic cAMP-dependent protein kinase.
Authorship: Sánchez-Carrera D., Bravo-Navas S., Cabezón E., Arechaga I., Cabezas M., Yáñez L., Pipaón C.,
Fuente: FASEB J. 2017 Jul;31(7):3007-3017
Publisher: Federation of American Society of Experimental Biology (FASEB)
Publication date: 01/07/2017
No. of pages: 16
Publication type: Article
DOI: 10.1096/fj.201601245R
ISSN: 0892-6638,1530-6860