Why do cancer cells spread in the human body?

A new study, co-authored by faculty from Binghamton University and the State University of New York, provides further insight
into how cancer cells spread.
Figuring out why cancer tumors form in the human body has been a goal for decades, but understanding how cancer cells spread is also key
to fighting this often deadly disease.
An osmotic engine model of cancer movement suggests that confined cells generate propulsion
by absorbing water at the leading edge and expelling it from the posterior.
However, the exact molecules that regulate these cellular retractions remain elusive
.

A new study published in the journal Nature Communications ("Polarized NHE1 and SWELL1 Regulate Migration Direction, Efficiency, and Metastasis") answers questions about cell motility, providing more steps
for future cancer treatments.
Yizeng Li, an assistant professor in the Department of Biomedical Engineering in Binghamton University's School of Engineering and Applied Sciences, joined this fall to co-author the paper
with collaborators from Johns Hopkins University, the University of Maryland, the University of Alberta, and Pompei Fabra University in Spain.

The researchers experimented with breast cancer cells in a three-dimensional matrix to study their behavior
.
As previously confirmed, a molecule called a sodium/proton exchanger 1 (NHE1) causes water to be absorbed — but the researchers also found that another protein in the back, called SWELL1, polarizes
cell membranes in a way that causes movement.

"We clearly show that NHE1 is concentrated on the front end and is responsible for water intake," Li said
.
"At the back of the cell, SWELL1 removes chlorine, and by removing chlorine, it also removes water
.
We finished the story
about how water enters and how it leaves.
Mechanobiology is the intersection of cell biology, physics, and mechanics
.
Much of my work has focused on cell migration, cell volume control, and other related issues
.
I built a mathematical model
for this work.
To better understand the biophysical mechanisms behind cancer cell movement, I developed a physiologically-based model rather than a phenomenon-based model
.
The model combines microscopic details
such as fluid dynamics, cytoskeletal structure, and ion transport.
The model predictions are in good agreement
with the experimental data.

About 40 percent of Americans are diagnosed with cancer at some point in their lives, and Li and her colleagues' research could have wide-ranging implications for slowing or stopping the deadly disease — even if treatment takes years
.

"We wanted to understand under what conditions tumor cells migrate, and under what conditions we can stop it
," she said.

Polarized NHE1 and SWELL1 regulate migration direction, efficiency and metastasis