Related Experiment Video
Updated: Jul 19, 2026
Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer
Published on: July 18, 2017
Hypertonic saline attenuates colonic tumor cell metastatic potential by activating transmembrane sodium conductance
Conor J Shields1, Desmond C Winter, John P Geibel
1Department of Surgery, National University of Ireland, Cork, Ireland. conor@narrowpoint.com
Abstract:
Hypertonic saline (HTS) suppresses tumor cell-endothelial interactions by reducing integrin expression. This translates into reduced adhesion, migration and metastatic potential. This study determined the relative contributions of hyperosmolarity and sodium-specific hypertonicity on the inhibitory effects of HTS, the intracellular pH and sodium responses to HTS and the role of cytoskeletal remodeling in these changes. Human colonic tumor cells (LS174T) were exposed to lipopolysaccharide under isotonic, hypertonic, sodium-free (N-methyl-D-glucamine), hyperosmolar (mannitol or urea), disrupted cytoskeletal (10 microg/ml cytochalasin D) conditions or in the presence of 5-(N-ethyl-N-isopropyl)amiloride (EIPA). Beta(1) integrin expression was measured flow-cytometrically. Intracellular sodium and pH were measured with confocal laser microscopic imaging. Statistical analysis was performed with analysis of variance, and P < 0.05 was considered significant. Data are represented as mean +/- SEM. Hypertonic exposure attenuated integrin expression (62.03 +/- 4.7% of control, P < 0.04). No discernible effect was observed with sodium-free or hyperosmolar solutions. HTS evoked a cellular alkalinization (by a mean 0.2 pH units) and an increase in cytosolic sodium concentration (by a mean 12.4 mM, P < 0.001) via upregulation of sodium-hydrogen exchange. Disassembly of actin microfilaments by cytochalasin D and antiporter inhibition with EIPA abrogated the effect of hypertonicity on integrin expression and intracellular sodium and pH (P < 0.05). HTS downregulates adhesion molecule expression via a hypertonic, sodium-specific, cytoskeletally mediated mechanism that involves activation of sodium-hydrogen exchange with associated changes in intracellular pH and sodium concentrations.
Insights
Hypertonic saline reduces tumor cell interactions by decreasing integrin expression, a process dependent on sodium and cytoskeletal changes. This mechanism inhibits cancer cell adhesion and metastasis.
Area of Science:
- Oncology
- Cell Biology
- Biochemistry
Background:
- Hypertonic saline (HTS) is known to suppress tumor cell-endothelial interactions by reducing integrin expression, consequently lowering adhesion, migration, and metastatic potential.
- The precise mechanisms underlying HTS's effects, particularly the roles of hyperosmolarity, sodium-specific hypertonicity, intracellular pH, and cytoskeletal remodeling, require further elucidation.
Purpose of the Study:
- To determine the relative contributions of hyperosmolarity and sodium-specific hypertonicity to the inhibitory effects of HTS on tumor cell-endothelial interactions.
- To investigate the impact of HTS on intracellular pH and sodium concentrations within tumor cells.
- To explore the role of cytoskeletal remodeling in mediating the effects of HTS.
Main Methods:
- Human colonic tumor cells (LS174T) were treated under various conditions: isotonic, hypertonic, sodium-free (N-methyl-D-glucamine), hyperosmolar (mannitol or urea), with cytoskeletal disruption (cytochalasin D), or with sodium-hydrogen exchange inhibition (EIPA).
- Beta(1) integrin expression was quantified using flow cytometry.
- Intracellular sodium and pH levels were monitored using confocal laser microscopy.
Main Results:
- Hypertonic exposure significantly attenuated beta(1) integrin expression (62.03% of control).
- Sodium-free or hyperosmolar solutions alone did not produce significant inhibitory effects.
- HTS induced cellular alkalinization (0.2 pH units) and increased cytosolic sodium concentration (12.4 mM) via sodium-hydrogen exchange upregulation.
- Cytochalasin D and EIPA treatments abrogated the effects of hypertonicity on integrin expression and intracellular ion/pH levels.
Conclusions:
- HTS downregulates tumor cell adhesion molecule expression through a hypertonic, sodium-specific mechanism.
- This process involves cytoskeletal remodeling and activation of sodium-hydrogen exchange, leading to alterations in intracellular pH and sodium concentrations.
- The findings highlight a novel pathway by which HTS can potentially inhibit cancer metastasis.
