136P - Investigating the evolutionary and regulatory dynamics of acquired resistance to BTK inhibitors in activated B-cell diffuse large B-cell lymphoma cells

Background

Activated B-Cell Diffuse Large B-cell lymphoma (ABC DLBCL) rapidly develops resistance to Bruton’s tyrosine kinase inhibitors (BTKi) that are effective in other blood cancers. However, in many cases, mutations in BTK or its effectors are either absent or do not initiate BTKi resistance acquisition. We hypothesise that acquired BTKi resistance results from the rewiring of gene regulatory networks and are investigating this process at the single-cell level.

Methods

We used in-house and public single-cell transcriptomics data from ABC DBLCL cell lines to study the transition from BTKi sensitivity to resistance. We also profiled the exomes and surface markers in BTKi-resistant and treatment-naïve U-2932 cells, in which we have previously generated bulk multiomics data (Artemov et al, in preparation). We are currently combining clonal tracing with single-cell transcriptomics to track the regulatory and evolutionary dynamics of BTKi resistance acquisition in real time.

Results

We confirm by exome sequencing that BTK and its effectors’ genes remain intact, and the pattern of profiled surface antigens remains mostly unchanged upon acquisition of BTKi resistance in U-2932 cells. Our single-cell RNA-seq data analysis showed marked differences in the gene expression dynamics and heterogeneity of BTKi-resistant cells, depending on the cell line.

Conclusions

Our pilot data point to a diversity of ABC DLBCL cell adaptations to BTKi treatment and strengthen the need to capture the dynamics and diversity of these adaptations in real time, motivating our clonal tracing experiments. Our ultimate goal is to identify evolutionary dynamics and vulnerabilities in the gene regulatory networks of BTKi-resistant cells, which could be targeted therapeutically.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The authors.

Funding

MRC Laboratory of Medical Sciences.

Disclosure

T. Graham: Financial Interests, Personal, Other, co-inventor: Method for TCR sequencing (GB2305655.9), Method to measure evolutionary dynamics in cancers using DNA methylation (GB2317139.0); Financial Interests, Personal, Other, receives honorarium from: Genentech. D. Hodson: Financial Interests, Personal, Funding: GSK, AstraZeneca. M. Spivakov: Financial Interests, Personal, Other, Shareholder: Enhanc3D Genomics ltd. All other authors have declared no conflicts of interest.