Increased susceptibility to urethane-induced lung tumors in mice with decreased expression of connexin43.
Gap junction intercellular communication capacity and connexin expression are reportedly decreased in human lung cancer. The mechanisms by which connexins, the gap junction proteins, act as tumor suppressors are unclear. In order to understand the involvement of connexins in tumorigenesis, we analyzed the effect of the heterologous deletion of Gja1 [the connexin43 (Cx43) gene] on the development of lung adenomas in mice. Heterozygous (Cx43(+/-)) and wild-type mice (Cx43(+/+)) were treated or not with single doses of urethane at 15 and 17 days after birth. Twenty-five weeks later, both the number and size of nodules were increased in Cx43(+/-) mice as compared with Cx43(+/+) mice. Moreover, the lesions were histologically more aggressive in the heterozygous mice. However, no increase in spontaneous lesions was observed in the lungs of untreated Cx43(+/-) mice. Heterozygous mice effectively presented lower expression of Cx43 genes and decreased amounts of Cx43. In conclusion, our results indicate that deletion of one allele of the Cx43 gene clearly favors the carcinogenic effect of urethane administration and results in a higher susceptibility to lung adenoma formation in mice.
Avanzo
José Luis
JL
Laboratory of Experimental Oncology, Department of Pathology, Faculty of Veterinary Medicine and Zootechny, University of São Paulo, Avenida Prof. Dr Orlando Marques de Paiva 87, CEP 05508-900 São Paulo, Brazil.
Mesnil
Marc
M
Hernandez-Blazquez
Francisco Javier
FJ
Mackowiak
Ivone Isabel
II
Mori
Claudia Madalena Cabrera
CM
da Silva
Tereza Cristina
TC
Oloris
Sílvia Catarina Salgado
SC
Gárate
Ana Paula
AP
Massironi
Silvia Maria Gomes
SM
Yamasaki
Hiroshi
H
Dagli
Maria Lúcia Zaidan
ML
D000236:Adenoma / Q000139:chemically induced* / Q000235:genetics / Q000473:pathology; D000818:Animals; D002273:Carcinogens / Q000633:toxicity*; D018031:Connexin 43 / Q000235:genetics*; D004198:Disease Susceptibility; D017353:Gene Deletion; D006579:Heterozygote; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000235:genetics / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016196:S Phase / Q000187:drug effects; D014520:Urethane / Q000633:toxicity*
D002273:Carcinogens; D018031:Connexin 43; D014520:Urethane