A model for co-expression pattern analysis of genes implicated in angiogenesis and tumour cell invasion in cervical cancer

Abstract

To date, numerous genes have been identified which are involved in both tumour neovascularisation (angiogenesis) and tumour cell invasion, and most of them are also expressed to some extent under normal physiological conditions. However, little is known about how these genes co-express in these settings. This study was undertaken to quantitate mRNA levels in normal and malignant cervical tissues of nine selected genes (VEGF 121 , VEGF 165 , VEGF 189 , VEGF-C, eIF-4E, b-FGF, TSP-2, MMP-2 and MMP-9) implicated in the above processes using real-time quantitative RT–PCR. In addition, the Spearman's rank correlation was used to determine their co-expression patterns. The transcript levels for the different VEGF-A splice variants (VEGF 121 , VEGF 165 , VEGF 189 ) were at least 10-fold higher in the cancer cases, with the highest levels in the primary tumours demonstrating lympho-vascular space involvement. The lymphangiogenic factor VEGF-C and MMP-9 were upregulated 130- and 80-fold respectively in cervical cancers. The highest levels of VEGF-C mRNA were found in the lymph-node positive group. The transcript levels for b-FGF were similar in normal cervical tissue and early-stage cervical cancer, however, higher levels were found in the cervical cancers with advanced stage disease. Comparing gene transcript levels between recurrent and non-recurrent cervical cancer patients revealed significant differences ( P =0.038) in transcript levels for the angiogenesis inhibitor TSP-2, with the highest levels in non-recurrent cases. Co-expression pattern analysis in normal cervical tissue revealed highly significant co-expressions ( P <0.0001) between TSP-2 and most other genes analysed (VEGF 121 , VEGF 165 , VEGF-C, b-FGF and MMP-2). In cervical cancer, TSP-2 appears only to be highly co-expressed with MMP-2 ( P <0.0001). In contrast to normal cervical tissue, we found a highly significant co-expression ( P <0.0001) between MMP-9 and VEGF 189 in cervical cancer. The combined application of real-time quantitative RT–PCR and Spearman's rank correlation identifies gene transcripts which are simultaneously co-expressed. Our results revealed a significant co-expression between the angiogenesis inhibitor TSP-2 and most other genes analysed in normal cervical tissue. In cervical cancer, we found a strong upregulation of VEGF-C and MMP-9 mRNA, with a highly significant co-expression between MMP-9 and VEGF 189 . British Journal of Cancer (2002) 87 , 537–544. doi: 10.1038/sj.bjc.6600471 www.bjcancer.com © 2002 Cancer Research UK

Expression of endoglin (CD105) in cervical cancer

“…We did not observe an association between bFGF-expressing cells with the number of CD105 (or CD31)-positive vessels. An increase in bFGF mRNA expression has been reported during cervical tumour development (Fujimoto et al, 1997;Van Trappen et al, 2002), whereas a decrease in bFGF expression was reported in the study of Soufla et al (2005). To our knowledge, our study is the first study on bFGF-expressing cells in cervical carcinoma at the protein level using immunohistochemistry.…”

Molecular profiling of cervical cancer progression

“…Similar to AKT, MMP3 can also cause epithelial -mesenchymal transition in cancer (Radisky et al, 2005). Matrix metalloproteinase 9 plays a central role in connective tissue degradation, tumourinduced angiogenesis, cell proliferation/apoptosis and cell migration in various tumour types including cervical cancer (van Kempen and Coussens, 2002;Van Trappen et al, 2002;Zucker and Vacirca, 2004;Vazquez-Ortiz et al, 2005b). Recently, one study has shown that MMP9 forms a complex with the hyaluronan receptor CD44 on the surface of breast cancer cells and activates downstream TGF-b, facilitating tumour cell survival, invasion and metastasis (Yu and Stamenkovic, 2004).…”

“…These studies could direct new therapeutic strategies targeting specific candidate genes. Although a variety of genes have been implicated in cervical cancer invasion, migration and lymph node metastasis, most studies have used only cervical cancer cell lines or primary tumours (Shim et al, 1998;Ruutu et al, 2002;Van Trappen et al, 2002;Vazquez-Ortiz et al, 2005a). To our knowledge, no data are available on gene expression profile differences between primary tumours and matched metastatic or recurrent tumours in cervical cancer.…”

Phosphorylation of tyrosine 1214 on VEGFR2 is required for VEGF-induced activation of Cdc42 upstream of SAPK2/p38

“…VEGF is expressed and secreted by tumor cells in response to hypoxia, which contributes to tumor expansion associated with neovascularization (Barleon et al, 1997). Interestingly, the VEGF gene is upregulated in most types of cancers (Nakamura et al, 2002;Van Trappen et al, 2002).…”