| Popis: |
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological disease, which arises from the malignant transformation of developing T-cell progenitors. Survival rates are nowadays up to 90% in children and 40% in adults. However, current therapy is associated with many short-term and long-term side effects, and survival rates after relapse or primary resistance remain very low. To address this challenge, current research is focused on revealing the underlying oncogenic mechanisms of the disease, which can contribute to the development of targeted treatment approaches. Recent advances in the sequencing technology have shown that combinations of different genetic abnormalities lead to the development of T-ALL. The relevance of many of these genetic abnormalities for the pathogenesis of T-ALL is still unknown, as is the reason for the co-occurrence of specific mutations. We speculate that oncogenic events that are frequently found together are likely to cooperate with each other and may have synergistic oncogenic effects. Therefore, I have studied cooperation between the NUP214-ABL1 tyrosine kinase and overexpression of the TLX1 transcription factor, since these two genetic aberrations are frequently found together in T-ALL cases. Using integrated ChIP-sequencing, ATAC-sequencing and RNA-sequencing data, I have demonstrated that TLX1 and STAT5, the downstream effector of NUP214-ABL1, selectively increase the accessibility of enhancer regions, and cooperatively activate the expression of key proto-oncogenes such as MYCand BCL2. Moreover, MYC is also part of the TLX1/STAT5 complex and inhibition of both STAT5 and MYC leads to reduction of target gene expression and induction of leukemia cell death. Exploiting this knowledge, I could show that treatment with imatinib (ABL1-inhibitor) together with a BET or BCL2 inhibitor works synergistically in vitroand in vivo. Studying the cooperation of oncogenes can thus reveal vulnerabilities in the leukemic cells that can be exploited for targeted therapy. Next, I wanted to optimize CRISPR/Cas genome editing for the generation of in vitromodels to study genetic aberrations found in T-ALL patients. I have generated the Fip1l1-Pdgfra tyrosine kinase fusion in the mouse pro B cell line Ba/F3, and I confirmed mechanistic insights that were previously studied in overexpression models. Furthermore, for a collaborative study with the lab of prof. Wlodarska, I generated different Alk tyrosine kinase fusions that are observed in patients with large anaplastic cell lymphoma, to study the mechanisms of transformation. Implementation of CRISPR/Cas genome editing in our experimental repertoire will allow us to further study genetic aberrations that are found in T-ALL. status: published |
