Abstract
Doxorubicin (Dox) is one of the most commonly used anthracyclines for the treatment of solid and hematological tumors such as B−/T cell acute lymphoblastic leukemia (ALL). Dox compromises topoisomerase II enzyme functionality, thus inducing structural damages during DNA replication and causes direct damages intercalating into DNA double helix. Eukaryotic cells respond to DNA damages by activating the ATM-CHK2 and/or ATR-CHK1 pathway, whose function is to regulate cell cycle progression, to promote damage repair, and to control apoptosis. We evaluated the efficacy of a new drug schedule combining Dox and specific ATR (VE-821) or CHK1 (prexasertib, PX) inhibitors in the treatment of human B−/T cell precursor ALL cell lines and primary ALL leukemic cells. We found that ALL cell lines respond to Dox activating the G2/M cell cycle checkpoint. Exposure of Dox-pretreated ALL cell lines to VE-821 or PX enhanced Dox cytotoxic effect. This phenomenon was associated with the abrogation of the G2/M cell cycle checkpoint with changes in the expression pCDK1 and cyclin B1, and cell entry in mitosis, followed by the induction of apoptosis. Indeed, the inhibition of the G2/M checkpoint led to a significant increment of normal and aberrant mitotic cells, including those showing tripolar spindles, metaphases with lagging chromosomes, and massive chromosomes fragmentation. In conclusion, we found that the ATR-CHK1 pathway is involved in the response to Dox-induced DNA damages and we demonstrated that our new in vitro drug schedule that combines Dox followed by ATR/CHK1 inhibitors can increase Dox cytotoxicity against ALL cells, while using lower drug doses.Graphical abstract• Doxorubicin activates the G2/M cell cycle checkpoint in acute lymphoblastic leukemia (ALL) cells.• ALL cells respond to doxorubicin-induced DNA damages by activating the ATR-CHK1 pathway.• The inhibition of the ATR-CHK1 pathway synergizes with doxorubicin in the induction of cytotoxicity in ALL cells.• The inhibition of ATR-CHK1 pathway induces aberrant chromosome segregation and mitotic spindle defects in doxorubicin-pretreated ALL cells.
Highlights
Among the different types of DNA damages generated by endogenous or exogenous sources, those affecting single or double strands of DNA structure are the most deleterious ones for eukaryotic cells
We evaluated the efficacy of a new drug schedule combining Dox and specific Ataxia- and Rad3-related (ATR) (VE-821) or Checkpoint kinase 1 (CHK1) inhibitors in the treatment of human B−/T cell precursor acute lymphoblastic leukemia (ALL) cell lines and primary ALL leukemic cells
We found that the ATR-CHK1 pathway is involved in the response to Dox-induced DNA damages and we demonstrated that our new in vitro drug schedule that combines Dox followed by ATR/CHK1 inhibitors can increase Dox cytotoxicity against ALL cells, while using lower drug doses
Summary
Among the different types of DNA damages generated by endogenous or exogenous sources, those affecting single or double strands of DNA structure are the most deleterious ones for eukaryotic cells. Several tumor suppressors, involved in the DNA damage response (DDR) pathways, play a specific role in the identification and repair of these types of damages (Lupertz et al 2010; Spina et al 2013). With diverse functionality, participate to the DDR pathways: (i) the cell cycle checkpoint-related kinases, which are involved in the initial steps of the response and promote cell cycle delay upon the identification of a DNA damage and (ii) the DNA repair proteins, which are involved in the resolution of the identified damage (Ghelli Luserna Di Rorà et al 2017). Ataxia-telangiectasia mutated (ATM), ataxia- and Rad3-related (ATR) kinases and their downstream effectors (checkpoint kinase 2 (CHK2) and 1 (CHK1) kinase, respectively) play a central role in initial steps of the DDR pathways. Doxorubicin (Dox) is an anthracycline used in the treatment of solid and
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
