hTERT mRNA Expression Correlates with Matrix Metalloproteinase-1 and Vascular Endothelial Growth Factor Expression in Human Breast Cancer: A Correlative Study Using RT-PCR

Abstract

Background: Telomerase activity has been significantly associated with nodal metastasis and cellular proliferation in human breast cancer, indicating that its degree of expression has some form of vital control over the invasive nature of the malignancy concerned. Of the telomerase subunits, the reverse transcriptase (hTERT) is the main determinant of enzyme activity. Vascular endothelial growth factors (VEGF)-C and (VEGF)-D, matrix metalloprotease type 1 (MMP-1) and protease-activated receptors (PARs) have all been linked to promotion of tumour invasiveness and metastatic dissemination. This study aims to examine the association between hTERT transcription and that of VEGF-D, VEGF-C, MMP-1, PAR1a and PAR1b through a correlative analysis of the mRNA transcripts of these genes in human breast cancer. Materials and Methods: Breast cancer tissues (n=116) and normal tissues (n-31) were collected immediately after surgery and stored at -80ÆC until use. The level of hTERT transcripts from the prepared DNA from the above samples was determined using real time-quantitative PCR based on the Amplifluor technology. The levels of the transcript were generated from a standard that was simultaneously amplified with the samples. Normalisation against cytokeratin 19 (CK19) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was also carried out. Results: There was a positive correlation between hTERT mRNA expression (after CK19 normalisation) with both VEGF-D and MMP-1 in human breast cancer. PAR1 was seen to correlate with hTERT (after GAPDH normalisation) with a highly significant correlation with PAR1a alone. However there was no correlation between hTERT transcription and VEGF-C or with PAR1b alone. Conclusion: Our findings suggest that hTERT is a potential up-regulator of MMP-1, PAR1 and VEGF-D expression and this may explain its apparent control over the invasiveness and metastasis of the malignancy concerned.