All ETDs from UAB

Advisory Committee Chair

Majd Zayzafoon

Advisory Committee Members

Douglas R Hurst

Joseph G Pressey

Ralph D Sanderson

Kurt R Zinn

Document Type


Date of Award


Degree Name by School

Doctor of Philosophy (PhD) Heersink School of Medicine


Osteosarcoma (OS) is among the most frequently occurring primary bone tumors, primarily affecting adolescents and young adults. Despite improvements in OS treatment, more specific molecular targets are needed. One target of interest is alpha-Ca2+/calmodulin-dependent protein kinase II (α-CaMKII), a ubiquitous mediator of Ca2+-linked signaling, which has been shown to regulate tumor cell proliferation. Here, we show that α-CaMKII is highly expressed in primary OS tissue, and α-CaMKII deletion in human OS cell lines significantly reduces tumor burden in vivo. This inhibition of α-CaMKII results in decreased vascular endothelial growth factor (VEGF) protein secretion. Highly aggressive OS cells express VEGF receptor 2 (VEGFR-2), and respond to exogenous VEGF by increasing intracellular calcium. This response is ameliorated by CBO-P11 (VEGFR inhibitor), suggesting that secreted VEGF results in autocrine stimulated α-CaMKII activation. Moreover, CBO-P11 and the selective CaMKII inhibitor, KN-93, significantly reduce tumor burden in vivo, suggesting that OS tumor growth is controlled by CaMKII-regulated VEGF. We expound on these initial studies and show that the FDA approved drugs tamoxifen and bevacizumab inhibit CaMKII, and decrease in vivo tumor growth. Furthermore, we developed a novel preclinical mouse model to examine the metastasis of human OS. After amputation of the tumor containing hind limb, the incidence of pulmonary metastasis in saline treated mice was 100%, with no detectable metastases when mice are subcutaneously injected daily with tamoxifen (10 mg/kg/day) and twice weekly with bevacizumab (2 mg/kg/day). These results suggest that tamoxifen and bevacizumab may be effective at inhibiting primary tumor growth and preventing metastasis. OS cancer stem cells (CSCs) have been shown to express high levels of c-kit and Stro-1. Using fluorescence-activated cell sorting, we isolated CSCs (CD117+, Stro-1+) and double negative cells (DNCs) (CD117- and Stro-1-) from 143B OS cells. We show that 100% of mice injected with CSCs develop tumors and only 25% of mice injected with DNCs did so. Taken together, our results show a critical role of CaMKII in primary and metastatic tumor growth of human OS.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.