The use of doxorubicine at low doses for elevation of LAK-activity toward explants and cells of MC-rhabdomyosarcoma and В16 melanoma resistant to doxorubicin

Berezhnaya N.M., Vinnichuk Yu.D., Belova O.B.

Aim: To study the influence of doxorubicin at low doses on antitumor action of activated (LAK) and non-activated lymphocytes from lymph nodes toward tumor cells of mice bearing doxorubicin-resistant and doxorubicin-sensitive transplantable MC-rhabdomyosarcoma and B16 melanoma. Materials and Methods: The study was carried out on BALB/c mice bearing MC-rhabdomyosarcoma and С57BL/6 mice bearing В16 melanoma. Explants, tumor cells and lymphocytes were cultivated in diffusion chambers, filters were stained with hematoxylin by Karachi, and morphology of preparations was examined. Results: At the day 7 of tumor growth in mice bearing resistant MC-rhabdomyosarcoma, non-activated lymphocytes pretreated with low-dose doxorubicin possess the highest antitumor activity, and in mice bearing doxorubicin-resistant B16 melanoma the highest antitumor activity was detected for lymphocytes after combined cultivation with IL-2 and doxorubicin. At the day 14 of tumor growth, LAK obtained from lymphocytes pretreated with doxorubicin possess the highest cytotoxic activity toward resistant tumor cells both of MC-rhabdomyosarcoma and B16 melanoma. There was no such effect in the case of sensitive tumors. Conclusion: To elevate antitumor activity of LAK toward MC-rhabdomyosarcoma and B16 melanoma cells, low doses of doxorubicin could be used at certain conditions of LAK generation.