The inhibitory effect of 4-hydroxyphenyl retinamide (4-HPR) on metastasis of prostate adenocarinoma-III cells in Lobund-Wistar rats

Abstract

Tumor cells of transplanted prostate adenocarcinoma-III (PA-III) spread with very high frequency from the extravascular implant site through ipselateral lymphatic channels to the lungs in which they produce visible focal tumors. The latter enlarge, coalesce and eventually kill the host. This system was used to demonstrate the effect of a retinoid on metastasis. Lobund-Wistar (L-W) rats were administered 1 mmol 4-HPR/kg diet L-485, and control rats received the same diet without 4-HPR. After an interval, all rats were in-oculated subcutaneously with PA-III cells. When examined at autopsy, all rats had developed an anticipated tumor at the implant site. However, the numbers of focal PA-III tumors in the lungs were significantly reduced among the 4-HPR-treated rats compared to the control rats (P = 0.002).