Mitochondrial Hyperactivation and Enhanced ROS Production are Involved in Toxicity Induced by Oncogenic Kinases...

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• Targeted therapy with tyrosine kinase inhibitors (TKI) is effective for solid and hematological tumors.
• Patient relapse occurs due to mechanisms like gene amplification, mutations, or bypass pathways.
• Oncogene overexpression can lead to TKI resistance and drug addiction, where cells become dependent on the drug.

Purpose of the Study:

• To investigate the potential of discontinuous TKI therapy for relapsed hematologic malignancies.
• To explore the mechanisms of TKI resistance and drug addiction in chronic myeloid leukemia (CML) and anaplastic large cell lymphoma (ALCL).

Main Methods:

• Utilized two cell models: LAMA (CML) and SUP-M2 (ALCL), differing in resistance mechanisms.
• Analyzed cellular responses to TKI withdrawal, including oncogenic signaling, mitochondrial activity, and reactive oxygen species (ROS) production.
• Investigated rescue strategies by modulating downstream signaling and ROS levels.

Main Results:

• Drug withdrawal in both CML and ALCL models caused oncogenic signaling overload, increased mitochondrial activity, and significant ROS production.
• This led to genotoxic stress and massive cell death upon TKI discontinuation.
• In LAMA cells, blocking downstream signaling or reducing ROS with reduced glutathione rescued cells from death.

Conclusions:

• Discontinuous TKI therapy may benefit a subset of patients with relapsed hematologic malignancies.
• TKI resistance through oncogene overexpression can induce drug addiction, making cancer cells vulnerable to drug withdrawal.
• Understanding these mechanisms allows for the development of novel therapeutic strategies, including intermittent dosing and combination therapies.