Abstract 944: Chemokine receptor signaling as a new tool to improve lung cancer diagnostics and therapy

Background: The tumor microenvironment plays a critical role in cancer development, progression, and control. We demonstrated in vitro and in vivo that a bidirectional crosstalk between tumor-associated macrophages and cancer cells via CCR2-CCL2 and CX3CR1-CXCL1 signaling is fundamental for lung cancer growth and metastasis offers new treatment concepts. Aim: Our working hypothesis is to develop a new platform for specific chemokine receptor (CCR2) PET imaging and a range of theranostic applications in lung cancer. For this purpose, we planned to define the CCR2 expression in NSCLC as well as in SCLC, tumor cells as well as immune/inflammatory cells. Material and Methods: This is a multicenter trial with patients from Zentralklinik Bad Berka GmbH (n =100 NSCLC, n=100 SCLC). All patients gave informed consent according to the declaration of Helsinki. FFPE material was available in all cases. CCR2 CXCR4 and CX3CR1 expression was determined by immunohistochemistry with the avidin-biotin-peroxidase-complex. Results: Analyzing 96 NSCLC (47 adenocarcinoma, 49 squamous cell carcinoma) and 45 SCLC tumor samples, we found CXCR4 and CCR2 chemokine receptor expression in tumor, immune and inflammatory cells. In NSCLC, co-expression between CCR2 and CXCR4 staining was very high concerning their expression on tumor cells rising with higher tumor stages, proliferation rate and grading. CCR2 expression in immune cells was restricted to lower stages; the same pattern could be observed in 45 SCLC tumor samples where CCR2 expression on immune cells was found especially in limited disease rather than in metastatic disease; CXCR4 expression in tumor cells was found to be high in all stages of SCLC. To evaluate the therapeutic efficacy of CCR2 antagonism in vivo, we injected LLC1 s.c. into WT mice treated with CCR2 antagonist (RS504393) or vehicle. Notably, tumor growth was significantly inhibited in CCR2 antagonist-treated mice as compared with vehicle-treated mice. Discussion: Our preliminary results show a significant portion of CCR2 positive tumors - NSCLC as well as SCLC which would qualify for a CCR2-based imaging as well as - demonstrated in our mice models - CCR2 inhibitory strategies. This should be evaluated in further preclinical trials. Citation Format: Katalin Nagy-Major, Jörg Sänger, Harshad R. Kulkarni, Peter Fix, Almut Kunze, Amelie Lupp, Reiner Bonnet, Werner Seeger, Richard P. Baum, Patricia Grabowski, Rajkumar Savai. Chemokine receptor signaling as a new tool to improve lung cancer diagnostics and therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 944. doi:10.1158/1538-7445.AM2017-944