ETC-501 Is a Brain-Penetrant MNK Inhibitor That Potentiates TMZ-Induced Senescence and Sensitizes Glioblastoma Cells
Giselle Sek Suan Nah1, Yuk Kien Chong2, Fatin Nasha Sulaimi1
1Cancer and Stem Cell Biology Programme, Duke-NUS Medical School, Singapore, Singapore.
Abstract:
Glioblastoma (GBM) is the deadliest primary brain tumor in adults, with a median survival of only 15 months and fewer than 10% of patients surviving beyond 5 years. Despite aggressive multimodal therapies, including surgical resection, radiation, and temozolomide (TMZ) chemotherapy, recurrence is almost inevitable. The mitogen-activated protein kinase interacting kinases (MNK)-eIF4E axis plays a significant role in cancer cell survival, and MNK1 and MNK2 are upregulated in gliomas. In this study, we discovered that elevated MNK1/2 expression correlates with poor prognosis and aggressive GBM phenotypes. The development of ETC-501, a selective brain-penetrant MNK inhibitor, enabled modulation of key oncogenic pathways, including MYC signaling, DNA replication, cell-cycle regulation, and inflammation. ETC-501 effectively inhibited GBM proliferation, impaired DNA damage repair, delayed cell-cycle progression, and suppressed ribosome biogenesis. Notably, in combination with TMZ, ETC-501 not only enhanced senescence but also attenuated the senescence-associated secretory phenotype in GBM cells. The augmented senescence increased the vulnerability of GBM cells to the senolytic agent navitoclax, facilitating the targeted elimination of residual senescent cells. These findings underscore the therapeutic potential of MNK inhibition in GBM, offering a promising strategy to advance GBM treatment paradigms and improve patient outcomes.
Significance:
Targeting MNK1/2 enhances the efficacy of cancer therapy and promotes senescence to prime cancer cells for elimination by senolytic drugs, providing a treatment strategy to manage tumor recurrence in glioblastoma.
Insights
Targeting the MNK-eIF4E axis with ETC-501 inhibits glioblastoma (GBM) growth and enhances sensitivity to senolytic therapy. This MNK inhibition strategy offers a novel approach to combat aggressive brain tumors.
Area of Science:
- Oncology
- Molecular Biology
- Neuroscience
Background:
- Glioblastoma (GBM) is an aggressive brain tumor with poor prognosis despite standard treatments.
- The MNK-eIF4E pathway is implicated in cancer cell survival and is upregulated in gliomas.
- Elevated MNK1/2 expression correlates with poor GBM prognosis and aggressive tumor phenotypes.
Purpose of the Study:
- To investigate the role of MNK1/2 in GBM and evaluate the therapeutic potential of the MNK kinase inhibitor ETC-501.
- To assess the effects of ETC-501, alone and in combination with temozolomide (TMZ), on GBM cells.
- To explore the combination of MNK inhibition and senolytic therapy for GBM treatment.
Main Methods:
- Correlative analysis of MNK1/2 expression with GBM prognosis and phenotype.
- Treatment of GBM cells with ETC-501 to assess its impact on oncogenic pathways.
- Combination therapy studies involving ETC-501, TMZ, and the senolytic agent navitoclax.
- Evaluation of senescence induction and senescence-associated secretory phenotype modulation.
Main Results:
- Elevated MNK1/2 expression is linked to poor GBM prognosis.
- ETC-501 effectively inhibits GBM proliferation, DNA repair, cell cycle progression, and ribosome biogenesis.
- Combination of ETC-501 and TMZ enhances GBM cell senescence and reduces the senescence-associated secretory phenotype.
- This combination therapy sensitizes GBM cells to navitoclax, enabling targeted elimination of senescent cells.
Conclusions:
- MNK inhibition is a promising therapeutic strategy for glioblastoma.
- ETC-501 demonstrates significant anti-GBM activity by targeting key oncogenic pathways.
- Combining MNK inhibition with senolytic agents like navitoclax offers a novel approach to eliminate residual GBM cells and improve treatment outcomes.
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