Effects of three different anti-ErbB2 antibodies on prostate tumors

Abstract

Prostate cancer is the most commonly diagnosed malignancy in men in developed countries. ErbB2 contributes to prostate cancer progression by activating the androgen receptor in a steroid poor environment, thus promoting androgen-independent cell growth and survival. The consequent development of hormone refractory tumors is a major obstacle in prostate cancer therapy. The inhibition of ErbB2 signal transduction pathways by the use of human antibodies has been considered as a valuable alternative strategy for cancer therapy. Herein we report a comparative analysis of the antitumor effects of three different antibodies targeting different epitopes of ErbB2: Herceptin (Trastuzumab), 2C4 (Pertuzumab), and Erb-hcAb, a novel fully human compact antibody produced in our laboratory. We demonstrate that the in vitro and in vivo growth of both androgen- dependent and –independent prostate cancer cells is efficiently inhibited by Erb-hcAb, which shows antitumor effects on some cell lines more potent than those observed for either Herceptin or 2C4