Poster S6 - Determining the role of adhesome protein signaling in lung cancer metastasis

Introduction: Lung carcinomas are the leading cause of cancer-related mortality due to their high metastatic potential. Resistance and relapse are thought to arise from tumor-initiating cells, also known as cancer stem cells (CSCs), which can self-renew and give rise to new tumors, playing a crucial role in metastasis. Evidence suggests that CSC persistence may not solely result from pre-existing CSCs but rather from extracellular matrix (ECM) alterations triggering gene expression changes in somatic cancer cells that then give rise to CSC properties. Single-cell RNA sequencing data from the lab demonstrates that disruption of adhesome proteins, which include the network of structural and signaling proteins involved in regulating cell-matrix adhesion, along with exposure to stem cell factors in the culture media (e.g., a reprogramming media) within a somatic lung cancer cell line (A549) leads to enrichment of CSC subpopulations (ALDH3A1-high) as well as the emergence of a new cell subpopulation showing metastatic marker expression (S100A-high). Based on this data, we hypothesized that adhesome disruption through knockdown of adhesome gene Cysteine and Glycine Rich Protein 1 (via shCSRP1) can increase metastatic potential in vivo.

Materials and

Methods: To investigate this, somatic lung cancer cell lines (A549 and H1299) were treated via lentiviral transduction to knockdown the CSRP1 gene and were either fed with reprogramming media or standard cell growth medium. These cells were then injected subcutaneously into immunodeficient NSG mice and after 6 weeks organs were dissected, imaged, dissociated into single cells and sorted through flow cytometry to determine metastatic potential.

Results, Conclusions, and Discussions: We determined that shCSRP1 within both lung cancer cell lines (A549 and H1299) enhanced their metastatic aggressiveness. A549 cells required exposure to stem cell factors in the culture medium (reprogramming medium) to exhibit this effect, whereas H1299 cells, with high intrinsic CSC gene expression, displayed heightened metastatic potential regardless of extrinsic media conditions. Based on these findings, it appears that cancer cell metastatic potential hinges on two critical factors: 1) the activation of CSC gene expression programs and 2) the suppression of cell adhesion-associated signaling. These findings present a fresh perspective for addressing metastasis and averting recurrences in lung cancer patients.

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