Paracrine upregulation of VEGF receptor mRNA in endothelial cells by hypoxia-exposed Hep G2 cells
| Autor: | Makoto Suematsu, Hiromasa Ishii, Mikiji Mori, Yuichi Shinoda, Koichi Seto, Hidekazu Suzuki, Yuzuru Ishimura |
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| Rok vydání: | 1999 |
| Předmět: |
Umbilical Veins
medicine.medical_specialty Carcinoma Hepatocellular Physiology Receptor expression Biology chemistry.chemical_compound Paracrine signalling Growth factor receptor Downregulation and upregulation Proto-Oncogene Proteins Physiology (medical) Internal medicine Paracrine Communication Tumor Cells Cultured medicine Humans Receptors Growth Factor RNA Messenger Hypoxia Vascular Endothelial Growth Factor Receptor-1 Hepatology Gastroenterology Receptor Protein-Tyrosine Kinases Oligonucleotides Antisense Vascular endothelial growth factor Endothelial stem cell Hep G2 Receptors Vascular Endothelial Growth Factor Endocrinology chemistry Cell culture cardiovascular system Cancer research Endothelium Vascular |
| Zdroj: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 276:G92-G97 |
| ISSN: | 1522-1547 0193-1857 |
| Popis: | Although vascular endothelial growth factor (VEGF) plays a role in the growth of hypervascular tumors, mechanisms for paracrine regulation of its receptor expression on vascular endothelial cells remain unknown. This study aimed to investigate whether VEGF released from hypoxia-exposed Hep G2 cells alters expression of the two distinct receptors, kinase insert domain-containing receptor (KDR) and fms-like tyrosine kinase 1 ( flt-1), in human umbilical venous endothelial cells (HUVEC). Hep G2 cells were cultured in 20% or 1% O2 for 16 h to examine induction of VEGF mRNA and its protein expression. Conditioned medium from Hep G2 cells (CM) was applied to HUVEC under normoxic conditions, and expression of mRNA for the VEGF receptors was determined by RT-PCR. In response to the hypoxic challenge, Hep G2 cells upregulated VEGF mRNA and the release of VEGF. Hypoxia-CM preferentially stimulated the mRNA expression of flt-1 but not that of KDR in HUVEC. When the VEGF release from hypoxia-exposed Hep G2 cells was blocked by its antisense oligodeoxynucleotide, the endothelial flt-1 mRNA upregulation elicited by the hypoxia-CM was still maintained. These results suggest that hypoxia-exposed Hep G2 cells not only produce VEGF but also evolve paracrine induction of flt-1 through VEGF-independent mechanisms. |
| Databáze: | OpenAIRE |
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