(C-118) Differential Gene Expression of Patient Circulating Tumor Cells on Engineered Biomaterials

Thursday, October 12, 2023

2:00 PM – 3:00 PM PDT

Location: Exhibit Hall - Row C - Poster # 118

Presenting Author(s)

Lily Cordner

PhD Candidate
Brown University
Providence, Rhode Island, United States

Primary Investigator(s)

IW

Ian Wong

Associate Professor of Engineering
Brown University, United States

Co-Author(s)

PC

Paul Cao

Genomics Data Scientist
Brown University, United States

Introduction:: Circulating tumor cells (CTCs) isolated from the bloodstream represent a “missing link” between primary tumors and metastatic colonies, and may yield new insights into “homing” and “dormancy” at preferred dissemination sites. For instance, estrogen receptor positive (ER+) breast cancers preferentially metastasize to bone, with some metastases to liver and lung. Nevertheless, bone, liver and lung represent profoundly different metastatic niches with varied matrix, stromal, and immune components. In order to understand how CTC gene expression and mechanophenotype are regulated by matrix or stromal interactions, we seek to reverse engineer the metastatic niche using a tissue-mimetic microenvironment.

Materials and Methods:: Patient-derived breast cancer CTC lines were kindly provided by S. Maheswaran (Massachusetts General Hospital), and isolated from metastatic breast cancer patients with informed consent and IRB approval. CTC lines were cultured in suspension on Ultra Low Adhesion (ULA) plates or on Matrigel in a 96-well plate for four days, with regular imaging using confocal microscopy. After four days, CTCs were isolated from the media and Matrigel, using Corning Matrigel Recovery Solution, then sent for RNA-seq at Genewiz / Azenta. Gene expression profiling was performed using over representation analysis (ORA) and gene set enrichment analysis (GSEA). The ORA provided stringent and relaxed gene lists based on a significance threshold of FDR < 0.1 and p < 0.05, respectively.

Results, Conclusions, and Discussions:: CTCs exhibited profound differences in morphology when cultured in Matrigel, with dispersed few-cell clusters (Figure 1A), relative to low adhesion conditions, where they formed larger aggregated clusters (Figure 1B). Further, CTCs exhibit pronounced differences in gene expression across experimental conditions, including gene sets associated with surface receptors, extracellular matrix (ECM) proteins, cytokines, leukocytes, and proteins involved in extracellular signal-related kinases (ERK) signaling. Indeed, CTC signaling programs appear to be broadly mediated by downregulation of cell-cell adhesion and upregulation of cell-matrix adhesion on Matrigel.
We show that patient CTCs respond to different culture conditions by altering their mechanophenotype based on cell-cell and cell-matrix adhesions. Ongoing work will profile CTCs on different decellularized matrix, and the effect of chemotherapeutic drugs and targeted inhibitors.

Acknowledgements (Optional): : We thank S. Maheswaran (Massachusetts General Hospital) for the gift of CTC lines (BRx-68) and funding from NIGMS under P20GM109035.

References (Optional): :