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Decrease in growth factor receptors after treatment with serine protease inhibitor ONO-3403
Takaki Hiwasa1, Hideaki Shimada, Takenori Ochiai
1Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan. hiwasa@med.m.chiba-u.ac.jp
Abstract:
FOY-305 is a synthetic serine protease inhibitor and ONO-3403 is a derivative with a higher protease-inhibitory activity. The growth-suppressive effects of ONO-3403 were more prominent in Ha-ras-transformed NIH3T3 (ras-NIH) cells than in non-transformed NIH3T3 cells. After treatment of ras-NIH cells with ONO-3403 at 100-200 microg/ml, the percentage of cells found in G(1) phase decreased and, concomitantly, that in S phase increased. Molecular events caused by ONO-3403 were investigated by Western blot analysis using anti-phosphotyrosine antibody. The results showed a marked decrease in the tyrosine phosphorylation level of a 180-kDa protein after treatment with ONO-3403. This 180-kDa phosphotyrosine-containing molecule which was tentatively designated pY-p180 might be platelet-derived growth factor (PDGF) receptor since addition of PDGF to serum-starved NIH3T3 cells induced a marked tyrosine phosphorylation of the same size within 5 min. This was further confirmed by immunoprecipitation of cell extract with anti-PDGF-receptor antibody followed by Western blot analysis using anti-phosphotyrosine antibody. Treatment of T.Tn human esophageal carcinoma cells with ONO-3403 caused also decrease in pY-p180, which appeared to be epidermal growth factor receptor. Thus, ONO-3403 may induce growth suppression by down-regulation of cell surface growth factor receptors.
Insights
ONO-3403, a serine protease inhibitor derivative, suppresses cancer cell growth by reducing tyrosine phosphorylation of growth factor receptors like PDGF and EGF receptors.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Serine protease inhibitors are investigated for therapeutic potential.
- ONO-3403 is a potent derivative of FOY-305 with enhanced protease-inhibitory activity.
- Ras-transformed cells exhibit distinct responses to ONO-3403 compared to normal cells.
Purpose of the Study:
- To investigate the growth-suppressive mechanisms of ONO-3403 in cancer cells.
- To identify the molecular targets affected by ONO-3403 treatment.
- To explore the role of growth factor receptor signaling in ONO-3403's effects.
Main Methods:
- Cell culture of NIH3T3 and ras-NIH cells.
- Flow cytometry to analyze cell cycle distribution.
- Western blot analysis using anti-phosphotyrosine antibody.
- Immunoprecipitation with anti-PDGF-receptor antibody.
Main Results:
- ONO-3403 treatment led to cell cycle arrest in G1 phase and increased S phase in ras-NIH cells.
- A significant decrease in tyrosine phosphorylation of a 180-kDa protein (pY-p180) was observed.
- pY-p180 was identified as platelet-derived growth factor (PDGF) receptor in NIH3T3 cells.
- In T.Tn human esophageal carcinoma cells, ONO-3403 also reduced pY-p180, identified as epidermal growth factor receptor (EGFR).
Conclusions:
- ONO-3403 induces growth suppression in cancer cells.
- The mechanism involves the down-regulation of cell surface growth factor receptors, including PDGF and EGFR.
- This suggests a potential therapeutic strategy targeting growth factor receptor signaling.