TITLE:
TK1 Membrane Expression May Play a Role in the Invasion Potential of A549 Lung Cancer Cells
AUTHORS:
Evita G. Weagel, Juan Mejía, Roman Kovtun, Joshua Keller, Juan A. Arroyo, Richard A. Robison, Kim O’Neill
KEYWORDS:
Thymidine Kinase 1, Invasion, EMT
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.9 No.8,
August
24,
2018
ABSTRACT: Thymidine
kinase 1 (TK1) is a well-studied cancer biomarker. It is commonly found
upregulated in the serum of cancer patients, and its levels correlate with
stage and grade, disease progression, and prognosis. It has recently been
reported that TK1 localizes on the plasma cell membrane of hematological and
solid malignancies, and not on the membrane of normal healthy cells, and while
on the membrane, TK1 has enzymatic activity. However, the function of TK1 on
the surface membrane is not well understood.
Here, we hypothesize that it may have a role in tumor invasion and migration.
It has been shown that TK1 expression levels positively correlate with
epithelia to mesenchymal transition (EMT) markers in patients with breast
cancer as they progress from HER2+ to triple negative breast cancer. In this
study, we silenced TK1 expression by siRNA and show that TK1’s membrane expression
is significantly downregulated at 60 hours post transfection. Using a Matrigel-based quantitative invasion assay, we measured cell invasion potential
in cells either expressing or lacking TK1 on their membrane and found that
cells that lack TK1 on their membrane exhibit decreased invasion potential.
These results suggest that TK1’s presence on the membrane may play a role in
invasion and cell migration in cancer.