Discovery of Novel α-Carboline Inhibitors of the Anaplastic Lymphoma Kinase

Area of Science:

• Oncology
• Medicinal Chemistry
• Structural Biology

Background:

• Anaplastic lymphoma kinase (ALK) is a key driver in various cancers.
• ALK inhibitors show efficacy but face drug resistance challenges.
• Novel compounds are needed to overcome resistance to ALK-targeted therapies.

Purpose of the Study:

• To design, synthesize, and evaluate novel azacarbazole-based inhibitors of anaplastic lymphoma kinase (ALK).
• To identify compounds effective against both native and drug-resistant ALK mutants.
• To elucidate the structural basis of inhibition for lead compounds.

Main Methods:

• Synthesis and chemical evaluation of a series of azacarbazole derivatives.
• In vitro kinase inhibition assays against native and mutant ALK.
• Cell-based assays using Ba/F3 models and human ALK+ lymphoma cells.
• X-ray crystallography to determine the co-crystal structure of compound 149 with ALK kinase domain.

Main Results:

• Several azacarbazole inhibitors with submicromolar potency were identified.
• Compound 149 demonstrated selective inhibition of native and drug-refractory ALK kinase variants.
• Compound 149 showed efficacy in preclinical models, including Ba/F3 cells and human lymphoma cells.
• The 3D co-crystal structure revealed detailed interactions of compound 149 with the ALK kinase domain, particularly involving the hinge region and lysine 1150.

Conclusions:

• Azacarbazole derivatives represent a promising class of ALK inhibitors.
• Compound 149 is a potent and selective inhibitor effective against drug-resistant ALK mutants.
• The structural insights provide a basis for further optimization of ALK-targeted therapies.