Enhanced radiation lethality in partially synchronized solid mouse tumors
Todoroki, T.; Koike, S.; Tsunemoto, H.; Watanabe, I.
Cancer Research 42(12): 5231-5235
1982
ISSN/ISBN: 0008-5472 PMID: 7139626 Document Number: 185237
The combined effects of local irradiation on in vivo partially synchronized solid mouse tumors were studied. Syngeneic [NR-FS] fibrosarcoma cells were transplanted s.c. into the thighs of C3H/He mice. When the tumors grew to 179 mm3 in volume, 1-.beta.-D-arabinofuranosylcytosine (ara-C) was repeatedly injected i.p. followed by a single injection of vinblastine sulfate at 5 h after the end of the ara-C treatment. The mitotic indexes increased from 4% in control to 22-23% at 5 h after the ara-C treatment, and the level continued for another 5 h. Further treatment with vinblastine sulfate after the ara-C injections resulted in more effective accumulation of mitotic ells, i.e., 30% at the 6th h. The tumor was locally irradiated with a single dose of 3000 rads of .gamma.-rays at the maximum level of mitotic index. The results indicated a synergistic inhibition of tumor growth and an 84% prolongation of the 50% survival day beyond that of the nontreated control mice.