New models to define factors determining the growth and spread of human prostate cancer

The incidence of many cancers shows a sharp increase with age. This is particularly true of prostate cancer, which arises in many older males. Little or no morbidity is observed as the tumor develops in situ in the prostate. However, once malignant cells escape from the primary lesion and metastasize, the disease assumes a much more serious course. Here we report on the activity of human prostate cancer cells in culture as well as their behavior when transplanted into nude mice. In vitro, several lines of prostate carcinoma cells obtained from metastatic lesions were embedded in reconstituted basement membrane proteins (Matrigel) and found to exhibit highly invasive activity as observed with malignant cells from other types of tumors. Also, we report an improved method for obtaining an increased growth of human prostate cancer cells in nude mice by injecting these cells in Matrigel. Since there are no adequate animal models of prostate cancer, the systems described here may prove useful in defining events underlying the development and progression of the tumor cells to malignant status, as well as facilitate the analyses of novel therapeutic agents to prevent the growth and the spread of this cancer.