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

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.

Barbosa RSS ，Dantonio PM ，Guimarães T ，de Oliveira MB ，Fook Alves VL ，Sandes AF ，Fernando RC ，Colleoni GWB ... -  《-》

The Wee1 kinase inhibitor MK1775 suppresses cell growth, attenuates stemness and synergises with bortezomib in multiple myeloma.

Multiple myeloma stem-like cells (MMSCs) are responsible for initiation and relapse, though novel treatment paradigms that effectively eradicate MMSCs are yet to be developed. Selective inhibition of the cell cycle regulatory kinase Wee1 by MK1775 is being explored as a potential anti-cancer therapeutic. We report that higher expression of Wee1 is correlated with poor survival in multiple myeloma (MM). The MM models and patient-derived CD138+ plasma cells are particularly sensitive to the growth-inhibitory effects of the Wee1 inhibitor MK1775. MK1775 induces Mus81-Eme1 endonuclease-mediated DNA damage in S-phase cell cycle that results in a blockade of replication and then apoptosis. Furthermore, MK1775 strongly suppresses the features of stemness in vitro, in vivo and in primary CD138+ cells by decreasing ALDH1+ cell fraction and the expression of ALDH1. In addition, co-treatment of MK1775 with bortezomib is synergistic in vitro and in vivo. Bortezomib, although it enhances ALDH1+ cells, when combined with MK1775 abrogates this stimulatory effect on stemness. Considering MM as an invariably incurable malignancy due to the presence of heterogenic myeloma stem-like cells, our study presents inhibition of Wee1 as a promising targeted therapy for MM and provides a compelling rationale to further investigate the activity of MK1775 against myeloma in clinical settings.

Liang L ，He Y ，Wang H ，Zhou H ，Xiao L ，Ye M ，Kuang Y ，Luo S ，Zuo Y ，Feng P ，Yang C ，Cao W ，Liu T ，Roy M ，Xiao X ，Liu J ... -  《-》

Combined inhibition of Chk1 and Wee1 as a new therapeutic strategy for mantle cell lymphoma.

Chilà R ，Basana A ，Lupi M ，Guffanti F ，Gaudio E ，Rinaldi A ，Cascione L ，Restelli V ，Tarantelli C ，Bertoni F ，Damia G ，Carrassa L ... -  《Oncotarget》

Preclinical evaluation of the WEE1 inhibitor MK-1775 as single-agent anticancer therapy.

Guertin AD ，Li J ，Liu Y ，Hurd MS ，Schuller AG ，Long B ，Hirsch HA ，Feldman I ，Benita Y ，Toniatti C ，Zawel L ，Fawell SE ，Gilliland DG ，Shumway SD ... -  《-》

Chk1 inhibition and Wee1 inhibition combine synergistically to impede cellular proliferation.

Davies KD ，Cable PL ，Garrus JE ，Sullivan FX ，von Carlowitz I ，Huerou YL ，Wallace E ，Woessner RD ，Gross S ... -  《-》