Combined mTOR/MEK inhibition prevents proliferation and induces apoptosis in NF2-mutant tumors

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Neurofibromatosis type 2 (NF-2) is a tumor suppressor gene linked to various nervous system tumors.
• NF-2 mutations are associated with poorer prognosis and aberrant PI3K/mTOR pathway activation, suggesting a role in tumor development.
• PI3K/mTOR pathway inhibitors are potential therapeutic agents for NF-2 related tumors.

Purpose of the Study:

• To investigate the efficacy of PI3K/mTOR pathway inhibitors in suppressing tumor proliferation in NF-2 mutation models.
• To evaluate the effects of Trametinib and Vistusertib, individually and in combination, on tumor cell proliferation and apoptosis.
• To explore the impact of these inhibitors on the PI3K/mTOR/MEK pathway and merlin expression.

Main Methods:

• Utilized NCI-H2452 and HEI193 cell lines, representing NF-2 mutated tumors.
• Administered PI3K/mTOR pathway inhibitors Trametinib and Vistusertib.
• Assessed cell proliferation using CCK8 assays, apoptosis via flow cytometry, and in vivo tumor growth. Western blot analysis was performed to examine pathway modulation.

Main Results:

• Both Trametinib and Vistusertib significantly inhibited tumor cell proliferation and enhanced apoptosis in vitro for both cell lines.
• Combined treatment with Trametinib and Vistusertib yielded more significant anti-proliferative and pro-apoptotic effects.
• In vivo studies showed that the drug combination markedly reduced tumor volume and weight, alongside inhibition of the PI3K/mTOR/MEK pathway and increased merlin expression.

Conclusions:

• PI3K/mTOR pathway inhibitors effectively decrease proliferation of NF-2 mutation tumor cells by promoting apoptosis.
• Combination therapy with Trametinib and Vistusertib demonstrates superior therapeutic potential compared to monotherapy.
• Targeting the PI3K/mTOR pathway offers a promising strategy for managing NF-2 related tumors.