Combinatorial targeting of menin and the histone methyltransferase DOT1L as a novel therapeutic strategy for treatment of chemotherapy-resistant ovarian cancer

Abstract

Background Ovarian cancer (OC) is characterized by a low response rate and high frequency of resistance development to currently available treatments. The therapeutic potential of histone methyltransferase DOT1L inhibitor in OC cells has been demonstrated, but optimal efficacy and safety of this targeted therapy approach still require improvement. We set forth to evaluate if this problem can be overcome by combinatorial targeting of this epigenetic modifier and menin, one of its functional partners in chromatin. Methods siRNA-mediated gene knock-down and pharmacological inhibition of menin, a key component of the MLL/SET1 complex and a fitness gene in OC cells, coupled to cell proliferation assays on a panel of high grade serous OC cell lines, including chemotherapy-sensitive and -resistant clones, were applied in order to evaluate how depletion or blockade of this enzyme influences growth and viability of OC cells. RNA sequencing was applied to identify menin target genes and pathways, and the effects of combined inhibition of menin and DOT1L on growth and transcriptome of these OC models were evaluated. Results Silencing and pharmacological inhibition of menin exert antiproliferative effects in all OC cells tested and, in PEO1 and PEO4 cells, a profound impact on transcriptome via down-regulation of cell cycle regulatory pathways, aryl hydrocarbon receptor, MYC and KRAS signalling. We demonstrated association of menin and DOT1L in OC cells and identified a subset of genes co-regulated by the two factors. Interestingly, co-treatment with DOT1L and menin pharmacological inhibitors exerts an additive effect on growth inhibition on chemotherapy-sensitive and -refractory OC cells mediated by transcriptome changes controlled by menin and DOT1L activities. Conclusion These results indicate that menin functionally cooperates with DOT1L in OC cells modulating transcription of genes involved in key cellular functions including, among others, cell proliferation and survival, that are strongly affected by combined inhibition of these two epigenetic regulators, suggesting that this may represent a novel therapeutic strategy for chemotherapy-resistant OCs. Trial registration NA; The manuscript does not contain clinical trials.

DOT1L stimulates MYC/Mondo transcription factor activity by promoting its degradation cycle on chromatin

“…34,109 Recently, DOT1L has been recognized as a co-factor of the estrogen receptor in the breast, 110 and its expression has been associated with ER-negative 27 and triplenegative 28,111 tumors. Additionally, high levels of DOT1L expression correlate with poor outcomes in ovarian 29,[112][113][114] and colorectal 23,115 cancers, and alterations in the DOT1L gene have been linked to lung adenocarcinoma 116 and pancreatic cancer. 117 Since c-MYC amplification or overexpression is prevalent in cancer, 1 our findings suggest that DOT1L could play a global role in controlling oncogenic c-MYC activity.…”

Transcriptome Study in Sicilian Patients with Autism Spectrum Disorder

“…The BH correction is a method to control the false discovery rate (FDR), which is the expected proportion of false positives among the declared significant results [29]. Genes with a fold change ≥ 2.50 or ≤−2.50 (|FC| ≥ 2.50) and adjusted p values ≤ 0.05 (padj) (pdaj ≤ 0.05, as suggested by the literature [29][30][31][32], were considered differentially expressed. Heatmaps and volcano plots of the differentially expressed genes were generated using the ComplexHeatmap version 2.14.0 [33] and ggplot2 version 3.5.1 [34] packages in R, respectively.…”

PARP1-DOT1L transcription axis drives acquired resistance to PARP inhibitor in ovarian cancer

“…For instance, Liu et al observed that C/EBPβ enhances platinum resistance in ovarian cancer cells by reprogramming DOT1L/H3K79 methylation to maintain an open chromatin state [ 31 ], thereby augmenting the cisplatin resistance of tumor cells. Another recent study demonstrated that co-treatment with DOT1L and menin pharmacological inhibitors exerts an additive effect on growth inhibition in chemotherapy-sensitive and refractory OC cells [ 32 ]. However, the role of DOT1L in the development of PARPi resistance in ovarian cancer remains unclear.…”