Abstract

The screening of new anti-cancer drugs is a long and expensive process with only 5% of drugs showing efficacy in human clinical trials. For a drug to be successful, it requires preclinical studies using animal models which can recapitulate the disease in patients. In vitro and in vivo preclinical experiments with cell lines, organoids and animal models of cancer are used in developing and testing anti-cancer drugs. However, recapitulating the heterogeneity and complexity of human cancer in preclinical models remains a challenge. Here we show that the zebrafish tumor xenograft ZTX model is highly suitable for evaluating efficacy screening of newly developed anti-cancer compounds, providing a powerful tool for in vivo preclinical drug discovery and development with compound lead identification in just a couple of days. Furthermore, the ZTX model can be an ideal complement to mice models with the medium-to-high throughput, cost- and time-effective advantages of in vitro systems. In this study, we used the ZTX platform to screen 9 novel recombinant proteins targeting tumor angiogenesis and CD87. DU145 cancer cell line was used. Tumor cells were labeled with DiL red dye and subcutaneously co-implanted with compounds in two-day-old zebrafish embryos. The potential of compounds to reduce primary tumor size and metastasis was evaluated at 3 days post-tumor implantation. Avastin, and Herceptin positive controls were included.Results showed that, after 3 days of treatment, different anti-tumor efficacy responses from each compound were distinguished, depending on their unique design. It was also observed that most compounds exhibited higher anti-tumor efficacy compared to positive control. Furthermore, after three days of treatment, most of the compounds reduced the number of disseminated cells to the caudal venous plexus; however, this effect did not reach a mathematical significance. The obtained data revealed the most suitable candidate for fu