Targeting oncoprotein stability overcomes drug resistance caused by FLT3 kinase domain mutations

Area of Science:

• Oncology
• Molecular Biology
• Pharmacology

Background:

• FMS-like tyrosine kinase 3 (FLT3) mutations, particularly internal tandem duplications (ITDs), are common in acute myeloid leukemia (AML).
• FLT3 inhibitors show clinical success but acquired resistance limits long-term efficacy.
• FLT3-ITD is a client protein of heat shock protein 90 (HSP90).

Purpose of the Study:

• To investigate targeting HSP90 as a strategy to overcome drug resistance in FLT3-ITD mutated AML.
• To evaluate the efficacy of HSP90 inhibitors in degrading resistant FLT3-ITD mutants and inducing cancer cell toxicity.

Main Methods:

• Utilized HSP90 inhibitors to treat cells expressing drug-resistant FLT3-ITD mutants.
• Assessed the degradation of FLT3-ITD proteins.
• Evaluated the selective toxicity induced in FLT3-ITD expressing cells.

Main Results:

• HSP90 inhibition led to the degradation of inhibitor-resistant FLT3-ITD mutants.
• HSP90 inhibitors selectively induced toxicity in cells harboring FLT3-ITD mutations.
• This approach demonstrated efficacy against resistant FLT3-ITD forms.

Conclusions:

• Targeting HSP90 is a viable therapeutic strategy to overcome acquired resistance to FLT3 inhibitors in AML.
• HSP90 inhibitors represent a promising option for treating FLT3-ITD positive AML patients who develop secondary resistance.
• This highlights the potential of targeting protein stability pathways in drug-resistant cancers.