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Ribozyme approach to downregulate vascular endothelial growth factor (VEGF) 189 expression in non-small cell lung
Y Oshika1, M Nakamura, T Tokunaga
1Department of Pathology, Tokai University School of Medicine, Isehara-shi, Kanagawa, Japan.
Abstract:
The aim of this study was to further clarify the role of the cell-associated isoform of vascular endothelial growth factor (VEGF189) on tumour growth and vascularity. Five isoforms of VEGF have been identified with different biological activities. VEGF121, VEGF145, VEGF165, VEGF189, VEGF206 are generated by alternative splicing. We used a hammerhead-type ribozyme (V189Rz) to suppress VEGF189 mRNA. The V189Rz specifically cleaved exon 6 of VEGF189 mRNA, but showed no activity against the VEGF121 or VEGF165 isoforms. The V189Rz was introduced into the human non-small cell lung cancer (NSCLC) cell line (OZ-6/VR). The expression level of VEGF189 mRNA was decreased in the OZ-6/VR cells, while VEGF121 and 165 expression was unaltered. The OZ-6/VR cells xenotransplanted into nude mice showed markedly reduced vascularisation and growth, whereas the cell line did not show any decreased growth under tissue culture conditions. The OZ-6/VR cells (1 x 10(5) cells/mouse) formed no tumours, whereas the parental OZ-6 cells formed large tumours within 8 weeks. The specific suppression of VEGF189 by the ribozyme decreased vascularity and xenotransplantability of the lung cancer cell line. Thus, the cell-associated isoform of VEGF, VEGF189, might have a key role in stromal vascularisation and the growth of NSCLC xenografts in vivo.
Insights
Vascular Endothelial Growth Factor-189 (VEGF189) plays a key role in non-small cell lung cancer (NSCLC) tumor growth and vascularity. Suppressing VEGF189 specifically reduced tumor vascularization and growth in vivo.
Area of Science:
- Molecular Biology
- Cancer Research
- Biochemistry
Background:
- Vascular Endothelial Growth Factor (VEGF) exists in multiple isoforms generated by alternative splicing.
- VEGF isoforms exhibit distinct biological activities, influencing tumor progression.
- The role of the cell-associated VEGF189 isoform in tumor growth and vascularity requires further elucidation.
Purpose of the Study:
- To investigate the specific function of the VEGF189 isoform in non-small cell lung cancer (NSCLC) tumor growth and vascularity.
- To determine if targeted suppression of VEGF189 impacts tumor development in vivo.
Main Methods:
- Utilized a hammerhead-type ribozyme (V189Rz) designed to specifically cleave VEGF189 mRNA.
- Introduced V189Rz into a human NSCLC cell line (OZ-6/VR) to suppress VEGF189 expression.
- Assessed tumor vascularization and growth by xenotransplanting modified NSCLC cells into nude mice.
Main Results:
- V189Rz specifically reduced VEGF189 mRNA levels in OZ-6/VR cells without affecting VEGF121 or VEGF165.
- OZ-6/VR cells exhibited significantly reduced vascularization and tumor growth compared to parental OZ-6 cells when xenotransplanted.
- No significant decrease in growth was observed for OZ-6/VR cells under standard tissue culture conditions.
Conclusions:
- The cell-associated VEGF189 isoform is crucial for stromal vascularization and the growth of NSCLC xenografts in vivo.
- Specific suppression of VEGF189 using ribozymes effectively inhibits tumor vascularity and xenotransplantability.
- VEGF189 represents a potential therapeutic target for managing NSCLC growth.