» Articles » PMID: 7358773

Experimental Investigations on a Sequential Combination Chemotherapy Protocol

Overview
Specialty Oncology
Date 1980 Jan 1
PMID 7358773
Authors
Affiliations
Soon will be listed here.
Abstract

This paper deals with experimental investigations concerning the composition of a cytostatic three-drug-protocol in diploid Ehrlich-Ascites-Tumor (EAT) cells in vivo at a far advanced stage of the disease. Hydroxyurea (HU) and vincristine (VCR) were used in very low doses to induce a modification of the growth pattern of tumor cells alike partial synchronization. Adriamycin (ADM) was selected as cytocidal drug during DNA synthesis of the partially synchronized cells. It was found that the sequential combination of HU and VCR (first HU and 12 h thereafter VCR) caused the greatest alteration of growth pattern compared with other combination protocols. A further statistically significant increase of the degree of synchrony was observed after a second VCR administration -- 22 h after HU. By means of this protocol the EAT was subdivided into two proliferating subpopulations, a diploid and tetraploid one. The tetraploid population resulted from surviving cells being not able to perform dytokinesis correctly, so that polynuclear cells and cells with a large single nucleus containing tetraploid DNA values were created. With respect to therapy, the administation of ADM at the time of DNA synthesis of the partially synchronized cells resulted in a statistically significant prolongation of the mean survival time and in 30% of cures of the animals. The dosage of ADM was 2.6 mg/kg, i.e., a nonlethal dose (50% of the LD10). Other combinations, i.e., simultaneous or reversed sequential combinations, did not show any therapeutic improvement compared to single drug therapy of ADM.

References
1.
Jellinghaus W, Schultze B, Maurer W . The effect of vincristine on mouse jejunal crypt cells of differing cell age: double labelling autoradiographic studies using 3H- and 14C-TdR. Cell Tissue Kinet. 1977; 10(2):147-56. DOI: 10.1111/j.1365-2184.1977.tb00140.x. View

2.
WHEELER G, BOWDON B, Adamson D, VAIL M . Comparison of the effects of several inhibitors of the synthesis of nucleic acids upon the viability and progression through the cell cycle of cultured H. Ep. no. 2 cells. Cancer Res. 1972; 32(12):2661-9. View

3.
Silvestrini R, Gambarucci C, Dasdia T . [Biological activity of adriamycin in vitro]. Tumori. 1970; 56(3):137-48. DOI: 10.1177/030089167005600301. View

4.
Plagemann P, Richey D, Zylka J, Erbe J . Thymidine transport by Novikoff rat hepatoma cells synchronized by double hydroxyurea treatment. Exp Cell Res. 1974; 83(2):303-10. DOI: 10.1016/0014-4827(74)90343-7. View

5.
Singer R, GELFANT S . Continuous inhibition of DNA synthesis in mouse ear epidermis using hydroxyurea. Exp Cell Res. 1972; 73(1):270-1. DOI: 10.1016/0014-4827(72)90135-8. View