BRCA1 regulates caveolin-1 expression and inhibits cell invasiveness
Yang Wang1, Jing Yu, Qimin Zhan
1State Key Laboratory of Molecular Oncology, Cancer Institute and Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 17 Pan Jia Yuan Nan Li, Beijing 100021, China.
Biochemical and Biophysical Research Communications
|March 18, 2008
Summary
The BRCA1 gene influences caveolin-1 (CAV1) expression and localization. BRCA1 enhances CAV1 mRNA levels and promotes its membrane redistribution, potentially inhibiting cancer cell invasion.
Area of Science:
- Molecular Biology
- Cancer Research
- Cell Biology
Background:
- BRCA1 is a crucial tumor suppressor involved in DNA repair and cell growth.
- Caveolin-1 (CAV1) also acts as a tumor suppressor, regulating cell invasiveness.
- The relationship between BRCA1 and CAV1 is not well understood.
Purpose of the Study:
- To investigate the regulatory role of BRCA1 on caveolin-1 gene expression.
- To determine how BRCA1 affects the subcellular localization of caveolin-1.
- To explore the functional consequences of BRCA1-mediated caveolin-1 regulation on cancer cell behavior.
Main Methods:
- Reverse Transcription Polymerase Chain Reaction (RT-PCR) to quantify mRNA levels.
- Transfection and RNA interference (RNAi) to manipulate gene expression.
- Luciferase reporter assays to assess promoter activity.
- Immunofluorescence microscopy to visualize protein localization.
Main Results:
- BRCA1 was found to increase caveolin-1 mRNA levels.
- This increase was mediated by the transactivation of the caveolin-1 promoter region.
- BRCA1 induced the redistribution of caveolin-1 from the cytoplasm to the cell membrane.
- This redistribution was associated with reduced invasiveness and metastatic potential.
Conclusions:
- BRCA1 positively regulates caveolin-1 gene expression at the transcriptional level.
- BRCA1 influences caveolin-1 subcellular localization, shifting it to the cell membrane.
- These actions suggest a mechanism by which BRCA1 inhibits cancer cell invasion and metastasis.
Related Concept Videos
01:19Cadherins in Tissue Organization
The cadherins are a superfamily of cell adhesion molecules comprising over 180 variants, with specific tissues expressing a particular combination of cadherin types. Cadherins generally exhibit homophilic binding; i.e., cadherins on one cell bind to cadherins of the same or closely related type on another cell. Thus, cells of the same type have a specific affinity to bind to each other and sort themselves into clusters to form tissues.
Cell Sorting During Development
Cell sorting plays an...
Cell Sorting During Development
Cell sorting plays an...
01:35Cancer Cell Migration through Invadopodia
Invadosome is a broad category of cell surface structures with proteolytic activity that degrades the extracellular matrix (ECM). Invadosomes are present in normal cell types, including macrophages, endothelial cells, and neurons, as well as tumor cells. Although the macrophage podosomes and tumor cell invadopodia are classified as invadosomes, they have different structures, molecular pathways, and functions. Podosomes are short structures that last for a few minutes. However, invadopodia can...
01:24Small GTPases - Ras and Rho
Ras and Rho are small monomeric GTPases that act downstream of receptor tyrosine kinase (RTK) and regulate various cellular processes. These GTPases switch between active and inactive states by binding to guanine nucleotides.
Three regulatory proteins control their activity:
Three regulatory proteins control their activity:
02:34Inhibition of Cdk Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
01:15Receptor Downregulation in MVBs
Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR activation may...
01:20The Retinoblastoma Gene
Tumor suppressor genes are normal genes that can slow down cell division, repair DNA mistakes, or program the cells for apoptosis in case of irreparable damage. Hence, they play an essential role in preventing the proliferation of damaged cells.
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...