The use of doxorubicine at low doses for elevation of LAK-activity toward explants and cells of MC-rhabdomyosarcoma and B16 melanoma resistant to doxorubicin.

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 57BL/6 mice bearing 16 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.