Chronic lymphocytic leukemia (CLL) is the most frequent leukemia in adults and remains a major clinical challenge, with relapse and resistance frequently emerging despite advances with targeted therapies such as Bruton’s tyrosine kinase (BTK) inhibitors and BCL2 antagonists (venetoclax). One major limitation in preclinical drug development for CLL is the lack of a physiologically relevant and reproducible in vitro model that mimics the lymph node microenvironment. Interactions with CD4+ T cells and stromal components provide critical survival and proliferative cues through CD40L, IL4, and IL21, which are absent in suspension cultures. We have recently developed a game-changing tool to mimic lymph node microenvironment of CLL in vitro. The team of prof. Mraz introduced a co-culture system based on human HS5 stromal cells genetically engineered to express CD40L, IL4, and IL21. This system induces robust proliferation of primary CLL cells and recapitulates lymph node–specific gene expression signatures, including upregulation of MYC, NFκB, and E2F pathways. Furthermore, it enables functional testing of pharmacologic inhibitors in a controlled, yet physiologically relevant, ex vivo environment.
Building upon this innovation, the proposed project will utilize this model to test multiple small molecules that the team has prof. Prof. Mlinaric- Rascan has identified as potential therapeutic targets based on computational modelling and in vitro experiments. Moreover, the team of prof. Mraz will further characterize this system to understand the major transcription factors required for proliferation of CLL cells which would allow to propose novel therapeutic targets and test other small molecules with cytostatic and cytotoxic potential.