Abstract
Abstract Small molecules that inhibit angiogenesis are attractive drug candidates for cancer, retinopathies, and age-related macular degeneration. In vivo, phenotypic screening in zebrafish (Danio rerio) emerges as a powerful methodology to identify and optimize novel compounds with pharmacological activity. Zebrafish provides several advantages for in vivo phenotypic screens especially for angiogenesis, since it develops rapidly, externally, and does not rely on a functional cardiovascular system to survive for several days during development. In this study, we utilize a transgenic line that allows the noninvasive monitoring of angiogenesis at a cellular level. The inhibition of angiogenesis can be observed under a fluorescent stereoscope and quantified. To exemplify the versatility and robustness of the zebrafish screen, we have employed a series of 60 novel compounds that were designed based on a potent VEGFR2 inhibitor. Herein, we report their structure-based design, synthesis, and in vivo zebrafish screening for optimal activity, toxicity, and off-target effects, which revealed six reversible inhibitors of angiogenesis.