Remodeling the extracellular matrix environment and establishing distinct immune cell profiles enables the formation of brain metastasis in non-small cell lung cancer adenocarcinoma

Abstract Dissemination of tumor cells from the primary site of the lung to distant sites in non-small cell lung cancer (NSCLC) is poorly understood. With distinct mutation signatures in patients, altering pathways is critical to preventing tumor cell dissemination to distant sites. Towards this, we characterized 21 "trios" patient-matched brain metastases (BrM), primary tumors (LT), and normal samples (LN), revealing a pattern of extracellular matrix remodeling which suppressed immune cell infiltration. Our objectives were to (i) determine if clinically sampled primary lung tumors encode gene expression patterns distinct from normal tissue, suggestive of increased tumor invasiveness including brain metastasis, and (ii) determine the biologic underpinning of immune-suppressive information carryover from primary lung tumor to brain metastasis. Transformation of the normal lung cells to primary tumor cells suggested a breakdown in ECM axes primarily governed by upregulation of collagen (COL1A1, COL1A2, COL3A1, COL10A1), fibronectin (FN1), and matrix metalloproteinases (MMP7, MMP9, MMP11, MMP12, MMP13, MMP14) genes. Collectively, the primary tumor cells used MMPs to break down the main components of lung ECM and reorganized collagen and fibronectin in the tumor microenvironment to facilitate migration and invasion. Migration and subsequent cell adhesion in the brain microenvironment revealed upregulation of neural cell adhesion molecule (NCAM1) and phosphoprotein 1 (SPP1). These changes in ECM profiles between LT and BrM signify primary tumor cells' adaptation in the brain microenvironment. Further computational deconvolution revealed reduced HLA class II gene expression (HLA-DMA, HLA-DOB, HLA-DPA1, HLA-DPB1, HLA-DQA2, HLA-DQB2, HLA-DRA) correlated with lower CIBERSORTx enrichment scores of immune cell populations in BrM. Overall, using the matched sequencing information, we will present the underlying signaling gradients that dictate dissemination of primary lung tumor cells to the brain environment in the background of altered ECM environment using cellular models harboring EGFR, KRAS, and ALK driver mutations. Citation Format: Albert R. Wang, Jared Brown, Andrew Baschnagel, Darya Buehler, Christina Kendziorski, Gopal Iyer. Remodeling the extracellular matrix environment and establishing distinct immune cell profiles enables the formation of brain metastasis in non-small cell lung cancer adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B038.