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Updated: Mar 19, 2026
A Method for Screening and Validation of Resistant Mutations Against Kinase Inhibitors
Published on: December 7, 2014
High-content screening identifies kinase inhibitors that overcome venetoclax resistance in activated CLL cells
Sina Oppermann1, Jarkko Ylanko1, Yonghong Shi1
1Biology Platform, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada;
Abstract:
Novel agents such as the Bcl-2 inhibitor venetoclax (ABT-199) are changing treatment paradigms for chronic lymphocytic leukemia (CLL) but important problems remain. Although some patients exhibit deep and durable responses to venetoclax as a single agent, other patients harbor subpopulations of resistant leukemia cells that mediate disease recurrence. One hypothesis for the origin of resistance to venetoclax is by kinase-mediated survival signals encountered in proliferation centers that may be unique for individual patients. An in vitro microenvironment model was developed with primary CLL cells that could be incorporated into an automated high-content microscopy-based screen of kinase inhibitors (KIs) to identify agents that may improve venetoclax therapy in a personalized manner. Marked interpatient variability was noted for which KIs were effective; nevertheless, sunitinib was identified as the most common clinically available KI effective in overcoming venetoclax resistance. Examination of the underlying mechanisms indicated that venetoclax resistance may be induced by microenvironmental signals that upregulate antiapoptotic Bcl-xl, Mcl-1, and A1, which can be counteracted more efficiently by sunitinib than by ibrutinib or idelalisib. Although patient-specific drug responses are common, for many patients, combination therapy with sunitinib may significantly improve the therapeutic efficacy of venetoclax.
Insights
Novel treatments for chronic lymphocytic leukemia (CLL) show promise, but resistance can occur. Combining venetoclax with sunitinib may overcome resistance, improving outcomes for CLL patients.
Area of Science:
- Hematology
- Oncology
- Pharmacology
Background:
- Venetoclax (ABT-199) is a novel Bcl-2 inhibitor transforming chronic lymphocytic leukemia (CLL) treatment.
- Therapeutic resistance and disease recurrence remain significant challenges in venetoclax therapy.
- Kinase-mediated survival signals in proliferation centers are hypothesized to drive venetoclax resistance.
Purpose of the Study:
- To develop an in vitro model of the CLL microenvironment for drug screening.
- To identify kinase inhibitors (KIs) that can overcome venetoclax resistance in a personalized manner.
- To investigate the mechanisms underlying venetoclax resistance and the efficacy of KIs.
Main Methods:
- Primary CLL cells were cultured in an in vitro microenvironment model.
- An automated high-content microscopy-based screen of kinase inhibitors was performed.
- Mechanisms of resistance and drug interactions were examined.
Main Results:
- Significant interpatient variability was observed in KI effectiveness.
- Sunitinib emerged as the most effective clinically available KI against venetoclax resistance.
- Venetoclax resistance, driven by antiapoptotic proteins (Bcl-xl, Mcl-1, A1), was more efficiently counteracted by sunitinib than ibrutinib or idelalisib.
Conclusions:
- Personalized combination therapy may be crucial for overcoming venetoclax resistance in CLL.
- Sunitinib demonstrates potential as a combination partner to enhance venetoclax efficacy.
- Targeting microenvironmental signals with KIs offers a promising strategy for improving venetoclax therapy in CLL.
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