Related Experiment Video
Updated: Jul 31, 2026
Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions
Published on: December 20, 2017
Connexin43 suppresses MFG-E8 while inducing contact growth inhibition of glioma cells
G S Goldberg1, J F Bechberger, Y Tajima
1Biological Sciences, State University of New York, Buffalo 14260, USA. camgsg@Buffalo.edu
Abstract:
Gap junction expression has been reported to control the growth of a variety of transformed cells. We undertook parallel analysis of connexins Cx32 and Cx43 in glioma cells, which revealed potential mechanisms underlying this phenomenon and led to several novel findings. Cx43, but not Cx32, suppressed C6 glioma cell growth. Paradoxically, Cx32 transfection resulted in severalfold more dye transfer than Cx43. However, Cx43 transfectants shared endogenous metabolites more efficiently than Cx32 transfectants. Interestingly, a significant portion of Cx43 permeants were incorporated into macromolecules more readily than those that transferred via Cx32. Cx43 induced contact inhibition of cell growth but in contrast to other reports, did not affect log phase growth rates. Cell death, senescence, or suppression of growth factor signaling was not involved because no significant alterations were seen in cell viability, telomerase, or mitogen-activated protein kinase activity. However, suppression of cell growth by Cx43 entailed the secretion of growth-regulatory factors. Most notably, a major component of conditioned medium that was affected by Cx43 was found to be MFG-E8 (milk fat globule epidermal growth factor 8), which is involved in cell anchorage and integrin signaling. These results indicate that Cx43 regulates cell growth by the modulation of extracellular growth factors including MFG-E8. Furthermore, the ability of a Cx to regulate cell growth may rely on its ability to mediate the intercellular transfer of endogenous metabolites but not artificial dyes.
Insights
Connexin 43 (Cx43) suppresses glioma cell growth by modulating extracellular factors like MFG-E8. This regulation depends on intercellular metabolite transfer, not just dye passage.
Area of Science:
- Cell biology
- Molecular oncology
- Gap junction research
Background:
- Gap junctions play a role in regulating cell growth, particularly in transformed cells.
- Connexins (Cxs) are key components of gap junctions, with Cx32 and Cx43 being extensively studied.
- Understanding Cx function in glioma is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the distinct roles of connexins Cx32 and Cx43 in regulating glioma cell growth.
- To elucidate the mechanisms underlying Cx-mediated growth control, focusing on intercellular communication and signaling pathways.
- To identify novel Cx43-regulated factors involved in glioma progression.
Main Methods:
- Parallel analysis of Cx32 and Cx43 expression in C6 glioma cells.
- Transfection studies to assess the impact of Cx32 and Cx43 on cell growth and dye transfer.
- Analysis of endogenous metabolite sharing, cell viability, telomerase, and MAPK activity.
- Investigation of secreted growth-regulatory factors using conditioned medium, with a focus on MFG-E8.
Main Results:
- Cx43 significantly suppressed C6 glioma cell growth, while Cx32 did not.
- Cx32 mediated greater dye transfer, but Cx43 facilitated more efficient sharing of endogenous metabolites.
- Cx43 induced contact inhibition without affecting log-phase growth rates, cell viability, or MAPK activity.
- Cx43-induced growth suppression involved the secretion of growth-regulatory factors, notably MFG-E8.
Conclusions:
- Cx43 regulates glioma cell growth through modulation of extracellular factors, including MFG-E8.
- The capacity of connexins to regulate cell growth is linked to their ability to transfer endogenous metabolites, rather than artificial dyes.
- Cx43's role in contact inhibition and MFG-E8 modulation offers potential therapeutic targets for glioma treatment.
More Related Videos
09:40Characterization of Functionally Associated miRNAs in Glioblastoma and their Engineering into Artificial Clusters for Gene Therapy
Published on: October 4, 2019
11:00Real-Time Quantitative Measurement of Tumor Cell Migration and Invasion Following Synthetic mRNA Transfection
Published on: June 23, 2023
Related Concept Videos
03:14Notch Signaling Pathway
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
02:23Abnormal Proliferation