Preclinical Therapeutic Synergy of MEK1/2 and CDK4/6 Inhibition in Neuroblastoma

Abstract

Neuroblastoma is treated with aggressive multimodal therapy, yet more than 50% of patients experience relapse. We recently showed that relapsed neuroblastomas frequently harbor mutations leading to hyperactivated ERK signaling and sensitivity to MEK inhibition therapy. Here we sought to define a synergistic therapeutic partner to potentiate MEK inhibition. We first surveyed 22 genetically annotated human neuroblastoma-derived cell lines (from 20 unique patients) for sensitivity to the MEK inhibitor binimetinib. After noting an inverse correlation with sensitivity to ribociclib (CDK4/6 inhibitor), we studied the combinatorial effect of these two agents using proliferation assays, cell-cycle analysis, Ki67 immunostaining, time-lapse microscopy, and xenograft studies. Sensitivity to binimetinib and ribociclib was inversely related ( = -0.58, = 0.009). amplification status and expression were associated with ribociclib sensitivity and binimetinib resistance, whereas increased MAPK signaling was the main determinant of binimetinib sensitivity and ribociclib resistance. Treatment with both compounds resulted in synergistic or additive cellular growth inhibition in all lines tested and significant inhibition of tumor growth in three of four xenograft models of neuroblastoma. The augmented growth inhibition was attributed to diminished cell-cycle progression that was reversible upon removal of drugs. Here we demonstrate that combined binimetinib and ribociclib treatment shows therapeutic synergy across a broad panel of high-risk neuroblastoma preclinical models. These data support testing this combination therapy in relapsed high-risk neuroblastoma patients, with focus on cases with hyperactivated RAS-MAPK signaling. .

Transcriptomic profiling of 39 commonly-used neuroblastoma cell lines

“…2 and Table 3 (available online only)) . Of note, the tumor from which the NLF cell line was derived was MYCN copy number amplified by the fluorescence in situ hybridization, however, it is not amplified at the protein level 18 and therefore, as expected, has the lowest MYCN FPKM of all cell lines designated as MYCN amplified. All cell lines were concordant with known MYCN amplification status.…”

Identification of GPC2 as an Oncoprotein and Candidate Immunotherapeutic Target in High-Risk Neuroblastoma

“…Neuroblastoma cell lines were profiled by RNA and targeted DNA sequencing as previously described (Harenza et al, 2017; Hart et al, 2017) and neuroblastoma cell line GPC2 FPKM, MYCN amplification status, and TP53 and ALK mutation status was queried from these data sets.…”

Recent Advances of Cell-Cycle Inhibitor Therapies for Pediatric Cancer

“…Ribociclib was active in vitro in leukemia cells (17) and in vivo in mutant NOTCH1-driven T-ALL mouse models in combination therapy with corticosteroids and mTOR inhibitors (18). Dual inhibition of MEK1/2 (binimetinib) and CDK4/6 (ribociclib) achieved preclinical synergy (19), as well as ALK (ceritinib) and CDK4/6 (ribociclib) (20) in neuroblastoma.…”