Antitumor effect of a combination of 6-methylthioinosine and amphotericin B on mouse leukemia L1210

Synthesis of some novel thiocyanotopurine derivatives and investigation of their antimicrobial activity and DNA interactions

A series of 6-thiocyanatopurine derivatives introduced with different alkyl groups in position 9 was synthesized. The structures of the synthesized compounds were evaluated via spectroscopic methods and elemental methods of analyses. All the synthesized compounds were screened for their antibacterial activities against Gram-positive and Gram-negative bacteria and for their antifungal activities against yeast strains. All the synthesized compounds showed better antibacterial activities against Gram-positive bacteria compared to Gram-negative bacteria. DNA interactions with pBR322 DNA were determined. Most of the compounds caused conformational changes in DNA.

Synthesis and cytostatic activity of substituted 6-phenylpurine bases and nucleosides: application of the Suzuki-Miyaura cross-coupling reactions of 6-chloropurine derivatives with phenylboronic acids

The Suzuki-Miyaura reaction of protected 6-chloropurine and 2-amino-6-chloropurine bases and nucleosides with substituted phenylboronic acids led to the corresponding protected 6-(substituted phenyl)purine derivatives 6-9. Their deprotection yielded a series of substituted 6-phenylpurine bases and nucleosides 10-13. Significant cytostatic activity (IC(50) 0.25-20 micromol/L) in CCRF-CEM, HeLa, and L1210 cell lines was found for several 6-(4-X-substituted phenyl)purine ribonucleosides 12 (X = H, F, Cl, and OR), while the 6-phenylpurine and 2-amino-6-phenylpurine bases 10 and 11, as well as 2-amino-6-phenylpurine ribosides 13, were entirely inactive against these cell lines.

Inhibition of intracellular bleomycin hydrolase activity by E-64 leads to the potentiation of the cytotoxicity of peplomycin against Chinese hamster lung cells

N-(N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl)-agmatine (E-64), a thiol protease inhibitor, potentiated the cytotoxicity of peplomycin against the Chinese hamster lung (V79) cell. After the treatment of the cells with E-64 (50 micrograms/ml) for 12 h, bleomycin hydrolase activity of the cells was almost completely inhibited. V79 cells treated with [3H]peplomycin for 24 h in the presence of E-64 (50 micrograms/ml) accumulated twice as much [3H]peplomycin and five times less [3H]desamidopeplomycin compared with V79 cells treated in the absence of E-64. These results suggest that E-64 increases the sensitivity of V79 cells to peplomycin probably by inhibiting the intracellular bleomycin hydrolase activity.

Activity of a novel carotenoid analog, 4,4'-(3,7,12,16-tetramethyl-1,3,5,7,9,11,13,15,17-octadecanonaen -1,18- diyl) bis(1-ethylpyridinium) dibromide (Y-18598) on mouse leukemia P388

4,4'-(3,7,12,16-Tetramethyl-1,3,5,7,9,11,13,15,17-octadecanonaen-1 ,18-diyl) bis (1-ethylpyridinium) dibromide (Y-18598), a novel carotenoid analog with 1-ethylpyridine rings as terminal groups, was found to be effective against P388 leukemia which was refractory to amphotericin B and retinoic acid used as representatives of polyene-containing drugs. The life span of leukemic mice was increased by 56% over the control following administration of 2.5 mg/kg on days 1-5. Among these polyene-containing compounds, Y-18598 was the most highly cytotoxic to P388 leukemia cells in vitro.

The effect of amphotericin B on 67Ga biodistribution

The effect of Amphotericin B (AMB) on radiogallium biodistribution in mice was studied at various time intervals. Two doses of AMB (1 mg/kg and 10 mg/kg) were administered intraperitoneally into mice bearing EMT-6 mammary sarcomas. The tumor and tissue uptakes of 67Ga were calculated when the radioactivity was administered either as 67Ga-citrate or 67Ga-transferrin (Ga-Tf). The role of transferrin was also investigated by using doubly-labeled 67Ga-125I-Tf. Our results indicate that both the doses of AMB and the chemical form of the radiogallium administered affect the pattern of distribution in some distinct fashion. It was also found that although the administration of AMB results in an increase in tumor-associated transferrin, this does not necessarily result in a concomitant increase in radiogallium uptake. In general, the effects of AMB on various tissues uptake of 67Ga appear to be related to both acute and subacute toxicity.

Potentiation of cytotoxic effects of 5-fluorouracil by inosiplex on cancer cells

The antitumor effect of 5-fluorouracil (5-FU) was significantly enhanced by inosiplex which has been developed as a drug possessing antiviral activity. The enhancement of antitumor effect of 5-FU was demonstrated by experiments both in vitro and in vivo, viz. depression of the colony formation rate in cultures of HeLa cells (an established cell line of human cervical carcinoma), and prolongation of the survival of mice bearing transplanted Ehrlich ascites tumor of murine mammary carcinoma origin. The HeLa cell colony formation was synergistically decreased in the presence of 0.5-2.0 micrograms/ml of 5-FU combined with 100 micrograms/ml of inosiplex. Inosiplex did not cause any appreciable inhibition of cell growth at this concentration when added alone to the culture. The mean duration of survival of tumor-bearing mice was 18.2, 20.3, 31.9 and 47.1 days in the control group and groups receiving inosiplex, 5-FU, or a combination of 5-FU and inosiplex, respectively; hence significantly prolonged in the combined therapy regimen group as compared with the control and the 5-FU treated group (P less than 0.01).