Search

Angiosarcoma is a clinically aggressive tumor with a high rate of mortality. It can arise in vascular or lymphatic tissues, involve any part of the body, and aggressively spread locally or metastasize. Angiosarcomas spontaneously develop in the tp53 deleted (tp53del/del) zebrafish mutant. However, established protocols for tumor dissection and transplantation of single cell suspensions of angiosarcoma tumors result in inferior implantation rates. To resolve these complications, we developed a new tumor grafting technique for engraftment of angiosarcoma and similar tumors in zebrafish, which maintains the tumor microenvironment and has superior rates of engraftment.

Angiosarcoma is a clinically aggressive tumor with a high rate of mortality. It can arise in vascular or lymphatic tissues, involve any part of the body, and aggressively spread locally or metastasize. Angiosarcomas spontaneously develop in the tp53 deleted (tp53(del/del)) zebrafish mutant. However, established protocols for tumor dissection and transplantation of single cell suspensions of angiosarcoma tumors result in inferior implantation rates. To resolve these complications, we developed a new tumor grafting technique for engraftment of angiosarcoma and similar tumors in zebrafish, which maintains the tumor microenvironment and has superior rates of engraftment.

Zebrafish embryos are well suited as a model system to perform chemical biology experiments effectively in educational settings. We studied the effect of caffeine on heart rate (HR) and other phenotypes of zebrafish embryos using visual microscopy and simple imaging. Acute treatment with millimolar concentrations of caffeine in embryo medium caused a dose-dependent decrease in HR in 2-3-day-old zebrafish embryos, ultimately resulting in complete HR cessation. A characteristic pattern of decrease in HR was observed, with an initial acute drop in HR and a period of stabilization followed by complete cessation. The effects of caffeine were not reversed by cotreatment with ruthenium red and adenosine, agents known to be antagonistic to caffeine, or by changes in calcium concentration in embryo medium. Apparent cardiac arrhythmia and a typical kinking effect in the trunk/tail region were also observed because of caffeine treatment. Our results, taken together with previous reports, raise the possibility that caffeine exerts its effects on embryonic HR of zebrafish by inhibition of ether-a-go-go potassium channels. However, further experimentation is required to dissect the molecular basis of caffeine action. We demonstrate that such experiments can be used to explore the effect of small molecules, such as caffeine, on cardiovascular phenotypes and to encourage experimental design in chemical biology.

Tyrosine kinases have significant roles in cell growth, apoptosis, development, and disease. To explore the use of zebrafish as a vertebrate model for tyrosine kinase signaling and to better understand their roles, we have identified all of the tyrosine kinases encoded in the zebrafish genome and quantified RNA expression of selected tyrosine kinases during early development. Using profile hidden Markov model analysis, we identified 122 zebrafish tyrosine kinase genes and proposed unambiguous gene names where needed. We found them to be organized into 39 nonreceptor and 83 receptor type, and 30 families consistent with human tyrosine kinase family assignments. We found five human tyrosine kinase genes (epha1, bmx, fgr, srm, and insrr) with no identifiable zebrafish ortholog, and one zebrafish gene (yrk) with no identifiable human ortholog. We also found that receptor tyrosine kinase genes were duplicated more often than nonreceptor tyrosine kinase genes in zebrafish. We profiled expression levels of 30 tyrosine kinases representing all families using direct digital detection at different stages during the first 24 hours of development. The profiling experiments clearly indicate regulated expression of tyrosine kinases in the zebrafish, suggesting their role during early embryonic development. In summary, our study has resulted in the first comprehensive description of the zebrafish tyrosine kinome.