Co-inhibition of HDAC and MLL-menin interaction targets MLL-rearranged acute myeloid leukemia cells via disruption of DNA damage checkpoint and DNA repair

Abstract

While the aberrant translocation of the mixed-lineage leukemia (MLL) gene drives pathogenesis of acute myeloid leukemia (AML), it represents an independent predictor for poor prognosis of adult AML patients. Thus, small molecule inhibitors targeting menin-MLL fusion protein interaction have been emerging for the treatment of MLL-rearranged AML. As both inhibitors of histone deacetylase (HDAC) and menin-MLL interaction target the transcription-regulatory machinery involving epigenetic regulation of chromatin remodeling that governs the expression of genes involved in tumorigenesis, we hypothesized that these two classes of agents might interact to kill MLL-rearranged (MLL-r) AML cells. Here, we report that the combination treatment with subtoxic doses of the HDAC inhibitor chidamide and the menin-MLL interaction inhibitor MI-3 displayed a highly synergistic anti-tumor activity against human MLL-r AML cells in vitro and in vivo, but not those without this genetic aberration. Mechanistically, co-exposure to chidamide and MI-3 led to robust apoptosis in MLL-r AML cells, in association with loss of mitochondrial membrane potential and a sharp increase in ROS generation. Combined treatment also disrupted DNA damage checkpoint at the level of CHK1 and CHK2 kinases, rather than their upstream kinases (ATR and ATM), as well as DNA repair likely via homologous recombination (HR), but not non-homologous end joining (NHEJ). Genome-wide RNAseq revealed gene expression alterations involving several potential signaling pathways (e.g., cell cycle, DNA repair, MAPK, NF-κB) that might account for or contribute to the mechanisms of action underlying anti-leukemia activity of chidamide and MI-3 as a single agent and particularly in combination in MLL-r AML. Collectively, these findings provide a preclinical basis for further clinical investigation of this novel targeted strategy combining HDAC and Menin-MLL interaction inhibitors to improve therapeutic outcomes in a subset of patients with poor-prognostic MLL-r leukemia.

A Box of Chemistry to Inhibit the MEN1 Tumor Suppressor Gene Promoting Leukemia

“…Candidates to increase clinical effectiveness include inhibitors of MLLr‐ relevant pathways (e. g., HDAC, p300/CBP, DOT1L and/or kinase inhibitors) or future inhibitors of menin‐LEDGF interactions. A recent study combined HDAC inhibitor chidamide with MI‐3 to show showed increased inhibition of human MLLr AML cell lines in vitro and in the xenograft model [111] . In addition, synergistic effects of the DOT1L inhibitor EPZ004777 and MI‐2‐2 have been observed in MLLr xenografts [112] …”

Discovery of Selenocysteine as a Potential Nanomedicine Promotes Cartilage Regeneration With Enhanced Immune Response by Text Mining and Biomedical Databases

“…The assays-on-demand primers and probes and TaqMan Universal Master Mix were used to examine gene expression by the MiniOpticonTM RT-PCR system (Bio-Rad, Hercules, CA, USA) according to the user’s manual and amplified detection was conducted using SYBR-Green RealMastcrMix (Bio-Rad). The expression values of mRNAs were normalized against glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and relatively calculated using 2 −ΔΔCt method ( Ye et al., 2019 ).…”

Anlotinib suppresses MLL-rearranged acute myeloid leukemia cell growth through inhibiting SETD1A/AKT-mediated DNA damage response

“…The assay of cell viability was performed as reported previously 16 . Briefly, 2 × 10 4 /well cells were seeded in 100 µl medium on 96-well plates and treated with indicated concentrations of Anlotinib for 24, 48, and 72 h. Then, 10 µl of the Cell Counting Kit-8(CCK-8) reagent (Dojindo, Kumamoto, Japan) was added to each well.…”

“…The assay was performed as reported previously 16 . In brief, cells were cultured and treated with Anlotinib for 24, 48, and 72 h in a same condition as described above.…”

“…For this reason, unexpected and major roles for wild-type MLL and its paralogs (MLL2 and SETD1A) have been observed in MLL-r leukemia 8,9,10 . Therefore, drugs targeting MLL homolog binding partners have been identified as potential therapeutic tools against MLL-r leukemia 11,12,13,14,15,16 . In addition, several inhibitors of signaling pathways such as PI3K/AKT/mTOR and MAPK show a promising antileukemia activity for treatment of MLL-r leukemia 17,18 .…”