Related Experiment Video
Updated: Aug 8, 2026
Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells
Published on: July 16, 2013
Disrupted traffic of connexin 43 in human testicular seminoma cells: overexpression of Cx43 induces membrane location
C Roger1, B Mograbi, D Chevallier
1INSERM EMI 00-09, 28 Avenue de Valombrose, 06102 Nice Cedex 2, France.
Abstract:
Connexins, the constitutive proteins of gap junctions, are considered to be tumour suppressive agents and are often impaired in the tumourigenic processes. In the present study, the expression of connexin 43 (Cx43), which is involved in the control of spermatogenesis through Sertoli/germ cell coupling, has been investigated in human testicular seminoma cells (tumours and the JKT-1 cell line). Cx43 was immunolocalized in the Golgi apparatus without membrane expression and was detected by immunoblotting in JKT-1 as exclusive 70 kD bands. No mutation could be found by sequencing the transcript obtained by RT-PCR. Transfection with a Cx43-V5 vector reproduced the same gel shift, identifying these 70 kD bands as Cx43. The Cx43-70 kD bands were also expressed in normal testicular tissue, associated with the classical 43 kD isoforms. Stable transfection of JKT-1 with a Cx43-GFP vector allowed restoration of Cx43 membrane expression, functional cell coupling, and inhibition of the cell proliferation rate. Storage of Cx43 in the Golgi apparatus may correspond during spermatogenesis to an intermittent physiological process that becomes permanent in malignant seminoma cells as a result of the tumourigenic process. By preventing Cx43 membrane expression, this disrupted traffic may itself participate in tumour promotion.
Insights
Connexins, like connexin 43 (Cx43), are tumor suppressors. In seminoma cells, Cx43 is improperly stored, hindering its function and potentially promoting tumor growth.
Area of Science:
- Oncology
- Cell Biology
- Molecular Biology
Background:
- Connexins (gap junction proteins) are recognized as tumor suppressors, frequently compromised during tumorigenesis.
- Connexin 43 (Cx43) plays a role in spermatogenesis via Sertoli/germ cell communication.
Purpose of the Study:
- Investigate Cx43 expression and localization in human testicular seminoma.
- Determine the role of Cx43 trafficking in seminoma development.
Main Methods:
- Immunolocalization and immunoblotting of Cx43 in seminoma cells (JKT-1) and normal testicular tissue.
- RT-PCR and sequencing to detect Cx43 mutations.
- Gene transfection (Cx43-V5, Cx43-GFP) to assess Cx43 function and localization.
Main Results:
- In seminoma cells, Cx43 was localized to the Golgi apparatus, not the membrane, appearing as 70 kD bands.
- No mutations were found in the Cx43 transcript.
- Transfection restored Cx43 membrane expression, cell coupling, and inhibited proliferation in JKT-1 cells.
Conclusions:
- Improper intracellular retention of Cx43 in the Golgi apparatus of seminoma cells disrupts its tumor-suppressive function.
- This disrupted trafficking may contribute to seminoma tumor promotion by preventing membrane expression and cell coupling.
