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Updated: Aug 2, 2026
Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells
Published on: July 16, 2013
Endothelial cells contain a glycine-gated chloride channel
S Yamashina1, A Konno, M D Wheeler
1Laboratory of Hepatobiology and Toxicology, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7365, USA.
Abstract:
Glycine inhibited growth of B16 melanoma tumors in vivo most likely because of the inhibition of angiogenesis. Here, the hypothesis that the anticancer effect of glycine in vivo is due to expression of a glycine-gated Cl- channel in endothelial cells was tested. First, the effects of glycine on vascular endothelial growth factor-induced increases in intracellular Ca2+ concentration in a bovine endothelial (CPA) cell line were studied. Vascular endothelial growth factor (1 ng/ml) increased intracellular Ca2+ concentration, with peak values reaching 141 +/- 11 nM. Glycine blunted this increase dose dependently. Furthermore, the inhibitory effects of glycine were prevented by 1 microM strychnine, a glycine receptor antagonist, or when cells were incubated in Cl(-)-free buffer. Moreover, glycine increased influx of 36Cl into CPA cells approximately 10-fold; this reaction was also strychnine sensitive. Furthermore, mRNA similar to the beta-subunit of the glycine-gated Cl- channel from spinal cord was identified in endothelial cells by reverse transcription-polymerase chain reaction. In addition, Western analysis using antibody for the glycine receptor demonstrated expression of the beta-subunit of the glycine receptor. Importantly, glycine diminished serum-stimulated proliferation and migration of endothelial cells. Collectively, these data indicate that the inhibitory effect of glycine on growth and migration of endothelial cells is due to activation of a glycine-gated Cl- channel. This hyperpolarizes the cell membrane and blocks influx of Ca2+, thereby minimizing growth factor-mediated signaling.
Insights
Glycine inhibits melanoma tumor growth by blocking blood vessel formation. This occurs through glycine-gated chloride channels in endothelial cells, which reduce calcium influx and cell proliferation.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncology
Background:
- Glycine has shown potential in inhibiting B16 melanoma tumor growth in vivo.
- The mechanism is hypothesized to involve the inhibition of angiogenesis (new blood vessel formation).
Purpose of the Study:
- To investigate if glycine's anticancer effects are mediated by a glycine-gated chloride channel in endothelial cells.
- To determine the role of this channel in regulating endothelial cell function and tumor growth.
Main Methods:
- Studied glycine's effect on vascular endothelial growth factor-induced intracellular calcium increases in bovine endothelial cells (CPA).
- Utilized strychnine (glycine receptor antagonist) and chloride-free buffer to assess channel involvement.
- Measured 36Cl influx, reverse transcription-polymerase chain reaction (RT-PCR) for glycine receptor beta-subunit mRNA, and Western analysis.
- Assessed glycine's impact on serum-stimulated endothelial cell proliferation and migration.
Main Results:
- Glycine dose-dependently inhibited vascular endothelial growth factor-induced calcium influx in endothelial cells.
- Inhibitory effects were blocked by strychnine and chloride-free conditions, indicating a glycine-gated chloride channel.
- Glycine significantly increased 36Cl influx, confirming channel activity.
- Endothelial cells expressed mRNA and protein for the beta-subunit of the glycine-gated chloride channel.
- Glycine reduced endothelial cell proliferation and migration.
Conclusions:
- Glycine exerts its anti-angiogenic and anti-tumor effects by activating a glycine-gated chloride channel in endothelial cells.
- Channel activation leads to hyperpolarization, blocks calcium influx, and inhibits growth factor signaling.
- This mechanism underlies glycine's potential as an anticancer agent targeting angiogenesis.
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