LAUSR

Lung adenocarcinoma (ADC) is a heterogeneous group of tumors associated with dramatically different survival rates, even when detected at an early stage. The overarching goal of our research is to identify the cellular and molecular predictors of indolent and aggressive behavior of early lung ADCs. In the work presented here, we hypothesized that mass cytometry, a single cell proteomic approach, would allow the discovery of cellular determinants of early lung ADC behavior. To test this hypothesis, we prepared a mass cytometry panel of 34 labeled antibodies and validated their performance in four lung ADC cell lines (A459, H23, PC9 and H3211), and in peripheral blood mononuclear cells (PBMCs). We then tested our panel in a set of 11 early stage lung ADCs. Based on radiomics features, four of these ADCs were predicted to have long (LS), one intermediate and 6 short survival (SS) establishing the rationale for the comparisons. Tumors were disaggregated into a single cell suspension within one hour after resection and cryopreserved before mass cytometry analysis. We used unsupervised clustering algorithm FlowSOM to identify cellular subpopulations and analyze differences in their distribution both within the tumor microenvironment (TME) and the epithelial compartment. We found that predicted LS tumors had a higher proportion of leukocytes (p-value = 0.027), moderately enriched in CD8+ T cells (p-value = 0.5671), whereas predicted SS tumors had a higher proportion of fibroblasts/mesenchymal cells (p-value = 0.138). Additionally, tumors show high degree of heterogeneity with distinct protein expression profiles among epithelial subpopulations. Epithelial subsets with high vimentin and low HLA-DR, and other subsets expressing p-ERK and p-S6 were mainly present in predicted SS tumors, whereas subsets with a high HLA-DR and low vimentin were mainly present in predicted LS tumors. Also, similarities on the subsets distribution in some samples suggest the presence of ADC molecular subtypes. It remains to elucidate if the observed heterogeneity of the epithelial compartment in combination with a specific composition of the TME could lead to a stronger association with predicted survival. Our preliminary results of mass cytometry in early lung ADCs confirm a distinct cellular profile of epithelial and stromal cells among indolent vs aggressive ADCs. This work deserves further validation at the cellular and molecular level to gain further insights into tumor behavior. [Supported by UO1CA196405 to PPM.] Citation Format: Maria-Fernanda Senosain, Yong Zou, Deon B. Doxie, Aneri Balar, Rosana Eisenberg, Jonathan M. Lehman, Jonathan M. Irish, Pierre P. Massion. Single cell mass cytometry analysis distinguishes indolent from aggressive lung adenocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4701.