PB0708 - The tissue factor/thrombin axis limits spontaneous lymphatic metastasis in mice

Monday, June 26, 2023

18:30 – 19:30 ET

Room: Exhibition

Presenting Author(s)

Bal Krishan Sharma, MSc, Mphil, PhD (he/him/his)

Research Associate
Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
Cincinnati, Ohio, United States

Co-Author(s)

BF

Brenton Francisco

Assistant Professor
Mount Sinai Kravis Children's Hospital
New York, New York, United States
LR

Leah Rosenfeldt

Research Assistant IV
Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
Cincinnati, Ohio, United States
Rachel L. Cantrell

Doctoral Candidate
Immunology Graduate Program, University of Cincinnati College of Medicine, Cincinnati, Ohio
Cincinnati, Ohio, United States
AR

Alexey Revenko

Executive Director
Ionis Pharmaceuticals, Carlsbad, California
Carlsbad, California, United States
BM

Brett Monia

Chief Executive Officer
Ionis Pharmaceuticals, Carlsbad, California
Carlsbad, California, United States
Matthew J. Flick, PhD

Professor
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States
Joseph S. Palumbo, MD (he/him/his)

Professor of Pediatrics
University of Cincinnati and the Cincinnati Children's Hospital Medical Center
Cincinnati, Ohio, United States

Background: We have previously shown that tumor cell associated tissue factor (TF) promotes experimental metastasis in mice, but its role in spontaneous metastasis is not completely understood.

Aims: Understand the role of TF in spontaneous metastasis.

Methods: We generated CRISPR-Cas9 TF deficient clones of Lewis lung carcinoma (LLC) and B16F10 melanoma. We evaluated the metastatic potential of these cells in C57BL/6 mice with normal and low circulating prothrombin.

Results: The in vitro proliferation of TF-deleted LLC and B16F10 was indistinguishable from control TF-expressing clones and parental cells. Comparative analyses of experimental lung metastases (IV injection) in immunocompetent C57BL/6 mice demonstrated a ~100 fold decrease in lung foci with TF-deleted LLC and B16-F10 cells relative to controls. TF-deleted LLC and B16F10 cells exhibited tumor growth similar to control cells when transplanted into the dorsal subcutis of immunocompetent mice. We resected primary tumors after two weeks and evaluated spontaneous metastasis ~2 weeks after resection. We observed no difference in spontaneous hematogenous metastasis to the lungs. However, TF-deficient cells demonstrated significantly increased lymphatic metastasis relative to controls cells. We performed similar in-vivo studies with control and TF-deficient cell clones in mice with low (~10% of normal) or normal circulating prothrombin. Neither TF- nor prothrombin-deficiency impacted primary tumor growth. Prothrombin deficiency had no impact on the metastatic potential of TF-deficient cells, including the increased lymphatic metastasis seen with these cells. Prothrombin deficiency resulted in a modest decrease in the hematogenous metastatic potential of TF-expressing cells, but a significant increase in the lymphatic metastatic potential of TF-expressing cells (Figure 1).

Conclusion(s): These studies demonstrate that tissue factor plays a multifaceted role in metastasis. TF and thrombin appear to promote hematogenous metastasis, but limit lymphatic metastasis. These studies may provide one explanation why anticoagulation has demonstrated limited if any effect on tumor progression in clinical studies.