The expression of the von Hippel-Lindau gene product and its impact on invasiveness of human breast cancer cells

Mohammad K Zia, Khaled A Rmali, Gareth Watkins, Robert E Mansel, Wen G Jiang
International Journal of Molecular Medicine 2007, 20 (4): 605-11
The von Hippel-Lindau (VHL) gene is located on the short arm of chromosome 3, the mutations of which lead to the development of von Hippel-Lindau disease. The VHL gene is a putative tumour suppressor gene in VHL and a few other conditions, possibly by negative regulation of hypoxia- inducible factor-1 (HIF-1) and the stromal-derived factor-1 (SDF-1) receptor, CXCR4, via which the VHL protein negates angiogenesis and tumour cell migration. The current study investigated the expression of VHL at the mRNA and protein levels in clinical breast tumours and evaluated the impact of VHL on the invasion of human breast cancer cells in vitro. Primary breast cancer samples (n=124), adjacent non-cancerous breast tissues obtained from patients in cohort (n=33) and a panel of human breast cancer cells (n=12) were used. Tissue distribution of VHL protein in human breast cancer tissues was assessed using immunohistochemical analysis, and VHL transcript was determined using quantitative reverse transcription PCR. Breast cancer cell line MDA-MB-231 was transfected with a human VHL expression construct (pCR3-GFP/VHL) to allow forced overexpression of VHL in the cells. Invasiveness and migration of cancer cells were assessed using the Matrigel invasion and Cytodex-2 migration assays. Statistical analysis was performed using the Student's t-test. Our results showed that breast cancer cell lines MCF-7 and ZR-75-1 expressed very high levels of VHL transcripts, but the highly aggressive MDA-MB-231, MDA-MB-435 and MDA-MB-453 expressed either no VHL or a low level. The levels of VHL transcripts were significantly lower in grade 2 and grade 3 tumours (mean +/- SD, 1.36+/-0.55 and 0.9+/-0.37), compared with grade 1 tumours (12.3+/-7.6, p<0.002). Node-positive tumours had lower levels of VHL than node-negative tumours. Although tumours from patients with metastasis and from those who died of breast cancer had low levels of VHL, the most significant reduction in VHL was seen in tumours which developed local recurrence (p=0.03). The staining of VHL protein was most abundant in mammary epithelial cells and moderate in endothelial cells. Tumour cells in breast tissues had low to moderate VHL staining. pCR3-GFP/VHL-transfected MDA-MB-231 (MDA-MB-231VHL+) exhibited a reduced spontaneous in vitro invasiveness (14.8+/-2.7) compared with the control cells (18.4+/-1.4). MDA-MB-231VHL+ cells also lost their invasion response to HGF/SF, an invasion-inducing cytokine. The MDA-MB-231VHL+ cells had substantially reduced motility compared with that of the controls (14.8+/-0.7 for MDA-MB-231VHL+ and 20.7+/-1.2 for the control; p<0.001). Thus, VHL exerts inhibitory effects on the invasive and migratory capacity of breast cancer cells in vitro. Low levels of VHL occur in most aggressive breast tumours. Taken together, VHL is a powerful putative tumour suppressor gene in human breast cancer.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"