RGD Reference Report - Caveolin-1 mutations (P132L and null) and the pathogenesis of breast cancer: caveolin-1 (P132L) behaves in a dominant-negative manner and caveolin-1 (-/-) null mice show mammary epithelial cell hyperplasia. - Rat Genome Database

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Caveolin-1 mutations (P132L and null) and the pathogenesis of breast cancer: caveolin-1 (P132L) behaves in a dominant-negative manner and caveolin-1 (-/-) null mice show mammary epithelial cell hyperplasia.

Authors: Lee, H  Park, DS  Razani, B  Russell, RG  Pestell, RG  Lisanti, MP 
Citation: Lee H, etal., Am J Pathol. 2002 Oct;161(4):1357-69.
RGD ID: 8661765
Pubmed: PMID:12368209   (View Abstract at PubMed)
PMCID: PMC1867297   (View Article at PubMed Central)
DOI: DOI:10.1016/S0002-9440(10)64412-4   (Journal Full-text)

Caveolin-1 (Cav-1) is the principal structural protein of caveolae membranes that are found in most cells types, including mammary epithelial cells. Recently, we mapped the human CAV1 gene to a suspected tumor suppressor locus (7q31.1/D7S522) that is deleted in a variety of human cancers, as well as mammary tumors. In addition, the CAV1 gene is mutated (P132L) in up to approximately 16% of human breast cancers. The mechanism by which deletion or mutation of the Cav-1 gene contributes to mammary tumorigenesis remains unknown. To understand the role of the Cav-1 (P132L) mutation in the pathogenesis of human breast cancers, we generated the same mutation in wild-type (WT) Cav-1 and studied its behavior in cultured cells. Interestingly, the P132L mutation leads to formation of misfolded Cav-1 oligomers that are retained within the Golgi complex and are not targeted to caveolae or the plasma membrane. To examine whether the Cav-1 (P132L) mutant behaves in a dominant-negative manner, we next co-transfected cells with Cav-1 (P132L) and WT Cav-1, and evaluated their caveolar targeting. Our results indicate that Cav-1 (P132L) behaves in a dominant-negative manner, causing the mislocalization and intracellular retention of WT Cav-1. Virtually identical results were obtained when Cav-1 (P132L) was stably expressed at physiological levels in a nontransformed human mammary epithelial cell line (hTERT-HME1). These data provide a molecular explanation for why only a single mutated CAV1 allele is found in patients with breast cancer. Thus, we next investigated if functional inactivation of Cav-1 gene expression leads to mammary tumorigenesis in vivo. For this purpose, we performed mammary gland analysis on Cav-1-deficient mice (-/-) that harbor a targeted disruption of the Cav-1 gene (a null mutation). Interestingly, we show that inactivation of Cav-1 gene expression leads to mammary epithelial cell hyperplasia, even in 6-week-old virgin female mice. These data clearly implicate loss of functional Cav-1 in the pathogenesis of mammary epithelial cell hyperplasia, and suggest that Cav-1-null mice represent a novel animal model to study premalignant mammary disease.



RGD Manual Disease Annotations    Click to see Annotation Detail View

  
Object SymbolSpeciesTermQualifierEvidenceWithNotesSourceOriginal Reference(s)
CAV1HumanHyperplasia  ISOCav1 (Mus musculus) RGD 
Cav1RatHyperplasia  ISOCav1 (Mus musculus) RGD 
Cav1MouseHyperplasia  IMP  RGD 

Objects Annotated

Genes (Rattus norvegicus)
Cav1  (caveolin 1)

Genes (Mus musculus)
Cav1  (caveolin 1, caveolae protein)

Genes (Homo sapiens)
CAV1  (caveolin 1)


Additional Information