Published in Cancer Detection and Prevention 1998; 22(Supplement 1).

Responsiveness of prostate carcinoma bone and prostate tumors to Interleukin 2 therapy

1 GG Hillman PhD, 1 J Triest MD, 1 DJ Grignon MD, 2 CY Wang PhD, 1 RL Maughan PhD, 1 ML Cher MD, 1 JE Pontes MD, 1 JD Forman, 1 SV Kocher

Departments of Urology, Pathology and Radiation Oncology; 1 Wayne State University, Detroit, MI, USA and 2 State University of New York, Syracuse, NY, USA

AIM: We have developed bone and prostate tumor models in nude mice by intrafemoral or intraprostatic injection of PC-3 human prostate carcinoma cells. These models were used to study the effect of interleukin 2 (IL-2) for metastatic prostate carcinoma. METHODS: PC-3 cells were injected in femur cavity (IF) or prostate (PI). Tumors were recultured to produce PC-3/IF or PC-3/PI tumor lines. These cells were implanted IF or PI and on day 6, mice were treated with i.p. IL-2. IL-2 effect on tumor progression was assessed and histological studies were performed on bone and prostate sections. RESULTS: In the bone model, palpable tumors of 0.7cm were observed at the hip joint by day 21 and grew to 2cm by day 40 with inguinal lymph node metastasis. Bone histology showed tumor invading marrow cavity, bone and muscle tissues. In the prostate model, tumors of 0.4cm were obtained by day 16 and grew to 1-1.5cm by day 40 with para-aortic lymph node metastasis. In the bone model, IL-2 inhibited the formation of palpable tumor by 75% at a dose of 25,000 U/day for 5 days. Prostate tumor size also decreased by 94% after 2-3 weekly courses of 25,000-40,000 U/day IL-2. Histology showed multifocal hemorrhages, areas of necrosis with polymorphonuclear and lymphoid infiltrates both in bone and prostate tumors. Lymph nodes were not enlarged in responding mice. CONCLUSIONS: Our findings indicate that IL-2 can induce a systemic anti-tumor response in prostate carcinoma located either in bone or prostate.

KEY WORDS: mouse prostate bone tumors, .

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Paper presented at the International Symposium on the Impact of Biotechnology on Prediction, Prevention and Treatment of Cancer; Nice, France; October 24 - 27, 1998; in the section on Immunotherapy.