Sequential combination of bortezomib and WEE1 inhibitor, MK-1775, induced apoptosis in multiple myeloma cell lines

• Published in: Biochemical and biophysical research communications Vol. 519; no. 3; pp. 597 - 604
• Main Authors: Barbosa, Rebecca S.S., Dantonio, Paola M., Guimarães, Taís, de Oliveira, Mariana B., Fook Alves, Veruska L., Sandes, Alex Freire, Fernando, Rodrigo Carlini, Colleoni, Gisele W.B.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 12.11.2019
• Subjects: MK-1775; Myeloma; WEE1; Myeloma; WEE1; MK-1775
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2019.08.163

Multiple myeloma (MM) remains incurable due to high rates of relapse after various treatment regimens. WEE1 is a cell cycle related gene that regulates the G2/M checkpoint and promotes cell cycle suspension for consequent DNA repair. To date, there are clinical studies for the evaluation of WEE1 inhibitors in the treatment of solid tumors and studies on cell lines of non-MM hematological tumors. To perform in vitro functional studies to verify the effect of the inhibition of WEE1 on MM cell lines viability and its potential as therapeutic target. WEE1 expression was evaluated in 22 newly diagnosed MM patients and in four MM cell lines, RPMI-8226, U266 and SKO-007 and SK-MM2, by quantitative real-time PCR (qPCR). After treatment with the WEE1 inhibitor (MK-1775), with or without proteasome inhibitor (bortezomib) pretreatment, we assessed cell viability through Prestoblue functional test, microspheres formation in soft agar, and induction of apoptosis and cell cycle alterations by flow cytometry. All MM cell lines showed WEE1 expression by qPCR. RPMI-8226 and U266 showed a 50% reduction in cell viability after 24 h of incubation with MK-1775, at concentrations of 5 μM and 20 μM, respectively. SKO-007 showed dose and time dependence to this drug. Combination therapy with bortezomib and MK-1775 abolished the formation of soft agar microspheres in the RPMI-8226 cell line (also responsive to the use of both drugs) and U266, but SKO-007 was resistant to all drugs, isolated and combined. However, treatment of bortezomib followed by MK-1775 (sequential treatment) versus bortezomib alone showed statistically significant impact on cell lines total apoptosis: 88.8% vs 74.1% in RPMI-8222 (confirmed by cell cycle experiments); 92.5% vs 86.6% in U266; and 60.2% 30.9% on SKO-007 (p < 0.05). The sequential combination of bortezomib and WEE1 inhibitor, MK-1775, induced apoptosis in RPMI-8226, U266, and especially SKO-007 cell lines, more efficiently than the use of the same isolated drugs, highlighting its effect in inhibition of proliferation of tumor cells in MM cell lines. Our data suggest that WEE1 can figure as a MM target and that the sequential combination of bortezomib and MK-1775 may be explored in future clinical trials. •Our results demonstrated that after sequential treatment with bortezomib and MK-1775, there was an increase in the percentage of cell death in myeloma cell lines compared to the use of the same drugs alone.•The SKO-007 cell line, with a highly resistant bortezomib profile as a single agent, had the greatest impact on total apoptosis when treated with the combination of drugs.•Thus, the induction of total apoptosis in more than 85% of U266 cells and in 60% of SKO-007 cells with the combination of bortezomib and MK-1775 demonstrate the potential importance of this strategy for patients with MM and del 17p or mutation of TP53 (high risk).