4.1 Article

Pathological significance of intracytoplasmic connexin proteins: Implication in tumor progression

Journal

JOURNAL OF MEMBRANE BIOLOGY
Volume 218, Issue 1-3, Pages 73-77

Publisher

SPRINGER
DOI: 10.1007/s00232-007-9048-6

Keywords

gap junction; connexin; aberrant localization; tumor progression; hepatocellular carcinoma; huH7 cell; metastasis

Ask authors/readers for more resources

A considerable amount of evidence has established that gap junctional intercellular communication (GJIC) suppresses tumor development by halting the stage of tumor promotion. Consistently, GJIC is downregulated in tumors. The downregulation of GJIC is caused by not only the reduced expression level of connexin proteins but also their aberrant cytoplasmic localization. Although it has long been thought that cytoplasmic localization of connexin proteins is merely one of the mechanisms of the downregulation of GJIC, careful studies with human tumor samples have indicated that the expression level of intracytoplasmic connexin proteins correlates well with the grade of malignancy and the progression stage of tumors. Hypothesizing that intracytoplasmic connexin proteins should have their proper functions and that their increase should facilitate tumor progression such as cell migration, invasion and metastasis, we examined the effects of overexpressed connexin32 (Cx32) protein on the phenotype of human HuH7 hepatoma cells, which express a basal level of endogenous Cx32 only in cytoplasm. The cells were retrovirally transduced with the Tet-off Cx32 construct so that withdrawal of doxycycline from the culture medium could induce overexpression of Cx32 protein in cytoplasm. Even when overexpressed, Cx32 protein was retained in cytoplasm, i.e., Golgi apparatuses, and did not induce GJIC. However, overexpression of Cx32 protein in cytoplasm enhanced both the motility and the invasiveness of HuH7 cells and induced metastasis when the cells were xenografted into SCID mice. Taken together, cytoplasmic accumulation of connexin proteins may exert effects favorable for tumor progression.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.1
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available