Single cell characterization of B-lymphoid differentiation and leukemic cell states during chemotherapy in ETV6-RUNX1-positive pediatric leukemia identifies drug-targetable transcription factor activities
Alena Malyukova; Laura Oksa; Riikka Lund; Petri I. Mäkinen; Tapio Lönnberg; Mari Lahnalampi; Juha Mehtonen; Artturi Mäkinen; Olle Sangfelt; Maria Bouvy-Liivrand; Samuli Rounioja; Saara Laukkanen; Olli Lohi; Pekka Ruusuvuori; Susanna Teppo; Merja Heinäniemi; Riina Kaukonen; Aleksi Kokko
Single cell characterization of B-lymphoid differentiation and leukemic cell states during chemotherapy in ETV6-RUNX1-positive pediatric leukemia identifies drug-targetable transcription factor activities
Alena Malyukova
Laura Oksa
Riikka Lund
Petri I. Mäkinen
Tapio Lönnberg
Mari Lahnalampi
Juha Mehtonen
Artturi Mäkinen
Olle Sangfelt
Maria Bouvy-Liivrand
Samuli Rounioja
Saara Laukkanen
Olli Lohi
Pekka Ruusuvuori
Susanna Teppo
Merja Heinäniemi
Riina Kaukonen
Aleksi Kokko
BMC
Julkaisun pysyvä osoite on:
https://urn.fi/URN:NBN:fi-fe2021042821581
https://urn.fi/URN:NBN:fi-fe2021042821581
Tiivistelmä
Background Tight regulatory loops orchestrate commitment to B cell fate within bone marrow. Genetic lesions in this gene regulatory network underlie the emergence of the most common childhood cancer, acute lymphoblastic leukemia (ALL). The initial genetic hits, including the common translocation that fuses ETV6 and RUNX1 genes, lead to arrested cell differentiation. Here, we aimed to characterize transcription factor activities along the B-lineage differentiation trajectory as a reference to characterize the aberrant cell states present in leukemic bone marrow, and to identify those transcription factors that maintain cancer-specific cell states for more precise therapeutic intervention. Methods We compared normal B-lineage differentiation and in vivo leukemic cell states using single cell RNA-sequencing (scRNA-seq) and several complementary genomics profiles. Based on statistical tools for scRNA-seq, we benchmarked a workflow to resolve transcription factor activities and gene expression distribution changes in healthy bone marrow lymphoid cell states. We compared these to ALL bone marrow at diagnosis and in vivo during chemotherapy, focusing on leukemias carrying the ETV6-RUNX1 fusion. Results We show that lymphoid cell transcription factor activities uncovered from bone marrow scRNA-seq have high correspondence with independent ATAC- and ChIP-seq data. Using this comprehensive reference for regulatory factors coordinating B-lineage differentiation, our analysis of ETV6-RUNX1-positive ALL cases revealed elevated activity of multiple ETS-transcription factors in leukemic cells states, including the leukemia genome-wide association study hit ELK3. The accompanying gene expression changes associated with natural killer cell inactivation and depletion in the leukemic immune microenvironment. Moreover, our results suggest that the abundance of G1 cell cycle state at diagnosis and lack of differentiation-associated regulatory network changes during induction chemotherapy represent features of chemoresistance. To target the leukemic regulatory program and thereby overcome treatment resistance, we show that inhibition of ETS-transcription factors reduced cell viability and resolved pathways contributing to this using scRNA-seq. Conclusions Our data provide a detailed picture of the transcription factor activities characterizing both normal B-lineage differentiation and those acquired in leukemic bone marrow and provide a rational basis for new treatment strategies targeting the immune microenvironment and the active regulatory network in leukemia.
Kokoelmat
- Rinnakkaistallenteet [19207]