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Myelopoietic response in tumour-bearing mice by an aggregated polymer isolated from Aspergillus oryzae
G Z Justo1, N Durán, M L Queiroz
1Department of Pharmacology, Faculty of Medical Sciences, Universidade Estadual de Campinas-UNICAMP, P.O. Box 6111, CEP 13083-970, Campinas, Brazil.
Abstract:
The effects of magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA), a proteic aggregated polymer isolated from Aspergillus oryzae, on the growth and differentiation of granulocyte-macrophage progenitor cells (colony-forming unit-granulocyte-macrophage [CFU-GM]) in normal and Ehrlich ascites tumour-bearing mice were studied. Myelosuppression concomitant with increased numbers of spleen CFU-GM was observed in tumour-bearing mice. Treatment of these animals with MAPA (0.5-10 mg/kg) stimulated marrow myelopoiesis in a dose-dependent manner and reduced spleen colony formation. No changes were observed in total and differential marrow cell counts. The dose of 5.0 mg/kg MAPA, given prior or after tumour inoculation, was the optimal biologically active dose in tumour-bearing mice and this dose schedule also stimulated myelopoiesis in normal mice. MAPA significantly enhanced survival and concurrently reduced tumour growth in the peritoneal cavity. We propose that the modulatory effect of MAPA on the myelopoietic response may be related to its antitumour activity as a possible mechanism for regulation of granulocyte-macrophage production and expression of functional activities.
Insights
Magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA) stimulates bone marrow myelopoiesis and reduces tumor growth in mice. This compound shows potential for regulating immune cell production and fighting cancer.
Area of Science:
- Immunology
- Pharmacology
- Cancer Research
Background:
- Ehrlich ascites tumor induces myelosuppression and alters spleen colony-forming unit-granulocyte-macrophage (CFU-GM) counts.
- Understanding the impact of external agents on hematopoiesis during tumor progression is crucial.
Purpose of the Study:
- To investigate the effects of magnesium ammonium phospholinoleate-palmitoleate anhydride (MAPA) on myelopoiesis and anti-tumor activity.
- To determine the optimal dose and administration schedule of MAPA in normal and tumor-bearing mice.
Main Methods:
- Administration of varying doses of MAPA (0.5-10 mg/kg) to normal and Ehrlich ascites tumor-bearing mice.
- Evaluation of bone marrow and spleen CFU-GM counts.
- Assessment of tumor growth and animal survival rates.
Main Results:
- MAPA treatment stimulated marrow myelopoiesis and reduced spleen CFU-GM in a dose-dependent manner.
- An optimal dose of 5.0 mg/kg MAPA was identified, enhancing myelopoiesis in both normal and tumor-bearing mice.
- MAPA significantly reduced tumor growth and improved survival rates in tumor-bearing mice.
Conclusions:
- MAPA exhibits immunomodulatory effects, stimulating myelopoiesis and demonstrating anti-tumor activity.
- The proposed mechanism involves MAPA's regulation of granulocyte-macrophage production and function, contributing to its anti-cancer effects.
