IL-6 slows progress of prostate cancer tumors

In mice with human prostate cancer cell xenografts, treatment with interleukin-6 inhibits the growth of the tumor.

In the September 10th issue of the International Journal of Cancer, Dr. Qingcai Wang and colleagues at the University of Southern California in Los Angeles, note that the human prostate cancer cell line LNCaP can be permanently differentiated into a noninvasive quiescent neuroendocrine cell type by treatment with interleukin-6. In vivo, the researchers studied mice with xenografts of either LNCaP cells, or DU-145 cells, another human prostate cancer cell line that does not differentiate in response to interleukin-6. Interleukin-6 was administered for 3 weeks, either by injection around the tumor or by systemic administration from implanted pumps.The authors report that both forms of administration of interleukin-6 inhibited the growth of LNCaP xenografts by more than 75% compared to controls. The cytokine treatment had no effect on the DU-145 xenografts. Furthermore, the LNCaP tumors had significantly increased expression of the neuroendocrine markers neuro-specific enolase and beta III tubulin, the investigators said. In addition, more than 90% of the LNCaP tumor cells showed loss of Ki-67 expression, indicating that the interleukin treatment had resulted in G0 cell cycle arrest. The researchers conclude that “agents, like interleukin-6, capable of neuroendocrine transdifferentiation of prostate cancer cells, should be considered as a new therapeutic approach for the treatment of prostate cancer.”(Source: Int J Cancer 2004; 111:508-513: Reuters Health News: Oncolink: October 2004.)