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Diamine oxidase activity in human melanoma cell lines with different tumorigenicity in nude mice
Abstract:
The activity of diamine oxidase (DO, EC 1.4.3.6.) which converts putrescine into gamma-aminobutyraldehyde in the degradative pathway of polyamine, was studied in 4 human melanoma cell lines, 2 of which produce tumours in greater than 80% of nude mice (M3Dau, M4Beu), whereas the other 2 induce tumours in less than 25% (M1Dor, M2GeB). The activity of DO in these cells varies with the growth rate: 24 h after seeding there is an initial increase in DO activity, followed by a steep decline during exponential growth. At 96 h, when cells reach saturation density, the activity of DO is significantly greater in the highly tumorigenic cell lines than in the poorly tumorigenic cell lines. Kinetic studies show that for the highly tumorigenic lines apparent Km values are 10.6 X 10(-6)M +/- 0.2 (M3Dau) and 14.2 X 10(-6) M +/- 0.6 (M4Beu), whereas for the poorly tumorigenic lines the values are 4.5 X 10(-6) M +/- 0.3. After transplantation into nude mice, the M1Dor cell line, which exhibits a low Km (app.) for DO of which had high Km (app.) value. Km (app.) determination of DO could be an approach for characterizing human melanoma cells differing in their tumorigenic potential in nude mice.
Insights
Diamine oxidase (DO) activity differs between human melanoma cells with high and low tumor-forming potential. Higher DO activity and specific kinetic properties correlate with increased tumorigenicity in nude mice.
Area of Science:
- Biochemistry
- Oncology
- Cell Biology
Background:
- Polyamines are crucial for cell growth and proliferation.
- Diamine oxidase (DO) plays a role in polyamine catabolism.
- Melanoma cell tumorigenicity varies, necessitating markers for characterization.
Purpose of the Study:
- To investigate diamine oxidase (DO) activity in human melanoma cell lines.
- To correlate DO activity and kinetics with tumorigenic potential in nude mice.
- To explore DO kinetic parameters as potential biomarkers for melanoma aggressiveness.
Main Methods:
- Culturing of four human melanoma cell lines with differential tumorigenicity.
- Measurement of diamine oxidase (DO) activity at various growth phases.
- Kinetic analysis of DO, including apparent Km determination.
- Tumorigenicity assessment in nude mice post-transplantation.
Main Results:
- DO activity exhibited dynamic changes during melanoma cell growth.
- Significantly higher DO activity was observed in highly tumorigenic cell lines at saturation density.
- Kinetic studies revealed distinct apparent Km values for DO between highly and poorly tumorigenic lines.
- A low apparent Km for DO was associated with a poorly tumorigenic cell line.
Conclusions:
- Diamine oxidase (DO) activity and its kinetic properties are linked to the tumorigenic potential of human melanoma cells.
- DO kinetic parameter determination may serve as a method for characterizing melanoma cell aggressiveness.
- Understanding DO's role could offer insights into melanoma progression and therapeutic strategies.