RESUMO
OBJECTIVE: To study the cytotoxic activity of NK-92 cells irradiated against human ovarian cancer. METHODS: NK-92 cells were exposed to different doses of radiation and assayed for proliferation by a standard (3)H-thymidine incorporation assay and cell count by using trypan blue exclusion. The cytotoxic activity of NK-92 cells against targets was measured in a standard (51)Cr-release assay in vitro. The effectiveness of irradiated NK-92 cells on ovarian cancer was compared with the control group of cancers (without injection of irradiated NK-92 cells). RESULTS: (1) In vitro:The proliferation of NK-92 cells was inhibited by radiation of 4, 8 and 16 Gy, respectively. From the (3)H-thymidine incorporation data, irradiation by 4 Gy reduced cell proliferation to 29% of control, while 8 Gy reduced proliferation to 6%. The cytotoxicity of NK-92 cells at 4 Gy 2 days following irradiation was approximately 42%-62% for ovarian cancer cell HO-8910, while it was 33%-58% at 8 Gy. (2) In vivo: Tumor size in treatment group was (0.047 +/- 0.019) cm(3) on day 30 after inoculation, and (0.167 +/- 0.021) cm(3) on day 40 and (0.343 +/- 0.022) cm(3) on day 50, while the sizes were smaller in treatment group (P < 0.01). In addition, the tumor group animals died between 74-82 days after injection of HO-8910 cells, while the treatment group animals were alive over 120 days (P < 0.01). CONCLUSION: Our study indicates that injection of irradiated NK-92 cells may be a potentially effective treatment for human ovarian carcinoma.