Efeito dos imunossupressores ciclosporina microemulsão, micofenolato mofetil e rapamicina no desenvolvimento do tumor de Walker

Abstract

Purpose: The purpose of this study was to investigate the effect of 3 immunosupressive drugs on Walker's tumor development and to evaluate a novel isolation technique of these tumoral cells using a ficoll-hypaque gradient. Methods and Results, one million of tumoral cells were inoculated by sc. injection in the right axilary region in forty male Wistar rats, 4-8 weeks-age. Tumor volume (TV), % tumor growth/inhibition (Tl), and tumor weight (TW) were assessed and analysed by ANOVA multivariate and univariate assays. Experiment I: 1-Control (n=10), mineral water; 2-Rapamycin, 1.5mg/kg/day (Rapa, n=10); 3-Cyclosporin microemulsion, 10mg/kg/d, (CsA, n=10); 4-Mycophenolate mofetil, 10mg/kg/d (MMF, n=10). All drugs were introduced one day before tumor inoculation and administered p.o. over 10 days. On day 10, TV was smaller in Rapa than in Control (6.8±2.7cm3 vs. 14.9±4.2cm3, p<0.001) in opposition to CsA (13.9±3.0cm3, p=0.89). TV was lower in MMF than in Control (10.3±2.8cm3, p<0.05) and similar to CsA and Rapa Tl was -49.3% in Rapa and -28.3% in MMF. TW was also significantly lower in Rapa (3.7±1.2g), MMF (5.2±2.0g) as compared to CsA (8.8±2.1g) and Control (7.3±2.0g). Experiment II: Control (n=9); Rapa (n=8); Rapa+CsA (n=9); Rapa+MMF (n=9). All drugs were started 24 hr. before tumor inoculation and adiministered over 10 days. On day 10, TV was lower in Rapa, Rapa+CsA and Rapa+MMF as compared to Control (3.8±1.5cm3; 3.1±1.2cm3 and 4.6±2.7cm3 vs. 10.9±3.8cm ; p<0.0001). TW was also lower in theses groups than in Control (3.5±1.2g; 2.3±0.4g; and 2.7±1.1g vs. 7.3±1.4g; p<0.0001). Tl was -52.1% in Rapa, -68.5% in Rapa+CsA and -63% in Rapa+MMF. Experiment III: Control (n=7); CsA (n=9); MMF+CsA (n=8). Drugs were given p. o. over 10 days beginning 24 hr. before tumor inoculation. On day 10, TV was similar (p=0.435) in MMF+CsA (19.7±3.7cm3) as compared to CsA (18.3±3.4cmá) and Control (19.1±3.5cm''). TW was similar in theses groups (CsA=11.2±2.1g; MMF+CsA=9.9±2.8g; and Control=9.7±3.1g; p=0.457). Experiment IV: Control (n=7); Rapa (n=10); MMF (n=9). All drugs were started on Day 4 after tumor implant and administered over 7 days. On day 10, TV in Rapa and MMF were similar to Control (Rapa=13.2±3.2cm3and MMF=12.3±5.5cm3vs Control=14.9±7.4cm3; p=0.831) as well as TW (Rapa=5.2±1.6g and MMF=6.9±2.4g vs. Control=6.3±3.2g; p=0.229). Experiment V: Isolation Technique of Tumoral cells Using a Ficoll-Hvpaaue Gradient. The tumoral cells were centrifuged on a Ficolt-Hypaque gradient and one million cells tumoral were implanted in the right axilary region (n=10) and TV, Tl, and TW were compared with technique without the Ficoll-Hypaque gradient (n=10). On day 10, no differences were observed in TV (without ficoll=17.9±3.8 and with ficoll=17.214.4cm ; p=0.190) and TW (without ficoll=7.0±1.8g; with ficoll =7.3±2.8g, p=0.569). Experiment VI: the effect of Rapa on tumor growth was assessed using the tumor cell suspension obtained by a ficoll-hypaque gradient. Control (n=10) olive oil; Rapa (n=10). Treatment was started on Day 4 after tumor implant and administered p. o. over 10 days. On day 13, TV in Rapa (21.1 ±6.0 cm3) was similar to Control (24.9±6.4cm3; p=0.831). as well as TW on day 14 (Rapa=9.3±4.0g vs. Control=10.0±2.6g; p=0.445). Conclusions: A Ficoll-Hypaque gradient can provide more adequate isolation of Walker's carcinossarcoma cells. Rapamycin greatly inhibited tumor growth when used alone or in association with cyclosporin micro-emulsion or MMF. MMF when used alone in this model attenuated Walker's carcinossarcoma growth but this inhibitory effect was lost when MMF is used in combination with CsA. There was no synergism in the association Rapa + MMF in the inhibition of tumor growth The antiproliferative effect of Rapa or MMF was lost when either drug was administered in presence of a established tumor.