LE3 .A278 2018

2018

Easy, Russell
Berman, Jason N.

Acadia University

Bachelor of Science

Honours

Biology

Biology

Anthracyclines are potent anticancer drugs that play a prominent role in the modern era of chemotherapy. Unfortunately, the utility of these drugs, like doxorubicin, is limited by anthracycline-induced cardiotoxicity (ACT). Our collaborators have previously determined that a genetic mutation resulting in decreased activity of the retinoic acid receptor-γ (RARγ) leads to increased susceptibility to ACT; thus, the current study aims to investigate whether all-transretinoic acid (ATRA) and CD1530, known RARγ-agonists, can prevent ACT in zebrafish, whilst maintaining the chemotherapeutic effects of doxorubicin. The previously established zebrafish larval doxorubicin-induced pericardial edema phenotype was employed as a preclinical model using 125μM doxorubicin. These larvae were then co-treated for 72 hours with ATRA and CD1530. CD1530 was not lethal at low doses (0.1-1nM) but induced pericardial edema, while low doses (4-5nM) of ATRA protected against the pericardial phenotype, with significantly (p<0.001) reduced pericardial edema at 3 days post treatment (dpt). To determine expression patterns of both zebrafish RARγ gene homologs (RARγ-a and RARγ-b), whole-mount and fluorescence in situ hybridization (WISH and FISH) was completed at 24,48 and 72 hours post-fertilization (hpf) zebrafish using RNA probes. WISH and FISH were inconclusive based on their qualitative nature but there appeared to be low RARγ-b expression levels near the heart and publicly available databases suggest low expression levels of RARγ-a in developing zebrafish hearts (Chen et al., 2008). Current efforts include using the zebrafish xenotransplantation model, with K562 chronic myeloid leukemia cell line, to determine if ATRA impedes the anticancer effects of doxorubicin. Future studies will employ RISPR/Cas9 technology to create a RARγ-mutant zebrafish line for both pharmacogenomic and drug screening studies, with the ultimate goal of clinical translation and personalized medicine.

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https://scholar.acadiau.ca/islandora/object/theses:2691