CCR2 Expression Signature Can Classify and Predict Outcome in a Subpopulation of Chronic Lymphocytic Leukemia (CLL) Patients

• Published in: Blood 2020-11, Vol.136 (Supplement 1), p.13-14
• Main Authors: Parvin, Salma, Aryal, Aditi, Davids, Matthew S., Letai, Anthony G.
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2020-141642

Despite the recent advances in chronic lymphocytic leukemia (CLL) treatment with the development of novel targeted agents such as Bruton's tyrosine kinase (BTK) inhibitor ibrutinib and the BCL2 antagonist Venetoclax, the disease remains incurable for most patients, and resistance mechanisms to these novel agents have already been identified. Therefore, identifying new therapeutic vulnerabilities to treat and prevent resistant tumors is of great importance. Stromal cells provide CLL cells a protective niche which increases resistance to drug-induced apoptosis. Therefore, a current challenge is to develop new strategies by targeting not only CLL cells, but also the microenvironment. We found that soluble factors can recapitulate much of the protective function of stromal cells. To understand the role of microenvironmental factors on CLL cells, we took advantage of the conditioned media (CM) collected from the stromal cell line NK-tert, which protects CLL cells from spontaneous cell death. First, we identified three major cytokines (IL6, IL8, CCL2) from the conditioned media using Proteome Profiler Human XL Cytokine Array. Next, we evaluated the effect of each cytokine on peripheral blood (PB) CLL survival (n=5, treatment naïve, unselected regarding genetic background). CLL cells were cultured ex-vivo in CM and treated with neutralizing antibody against either Il6, IL8 or CCL2 for 48hrs and found a significant decrease in cell viability in presence of anti-CCL2 antibody (median % decrease in cell viability over isotype control is 50%, p