Investigating fibroblast growth factor and its role in canine osteosarcoma

fibroblast growth factor;canine osteosarcoma;differentiation

Camero, Corrine Michelle ; Stewart, Matthew, ; ,Selmic, Laura ; Fan ; Timothy M.

关键词: fibroblast growth factor;    canine osteosarcoma;    differentiation;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99310/CAMERO-THESIS-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Canine osteosarcoma (OS) is a malignant neoplasia of the osteoblast, most often identified in the appendicular skeleton, which is both locally aggressive and highly metastatic. The standard of care treatment of amputation and adjuvant chemotherapy yields a median survival time of 10-12 months, an improvement in which has not been noted despite active research. The biologic behavior of cancers seems to be correlated to the state of differentiation of the tumor cell population. Differentiation is taken into account when a histopathologic grade is assigned to a particular tumor; poorly differentiated tumors acquire a higher grade and are expected to behave more aggressively. The tumor microenvironment contains many cells and signaling molecules such as cytokines, chemokines and growth factors. Investigating these factors may identify a stimulus for a less differentiated and more aggressive neoplasia. This is even more compelling if the stimulus is a druggable target.Fibroblast growth factors (FGFs) interact with fibroblast growth factor receptors (FGFRs) to initiate cell signaling that is important in embryonic development, wound healing, and angiogenesis. FGF2, also termed basic FGF (bFGF), plays an important role in osteoblast proliferation and maintaining osteoblasts in an undifferentiated state.We hypothesize that 1) canine OS cells will express FGFRs and FGF2, 2) FGF signaling blockade will attenuate pro-tumorigenic properties in OS cells, 3) FGF signaling blockade will cause enhanced differentiation of the OS cell lines, and 4) circulating FGF2 will be increased in canine OS patients compared to healthy controls and increased in dogs with osteoblastic OS compared to those with osteolytic OS.We investigated FGFR gene expression with reverse transcriptase polymerase chain reaction (RT-PCR) and FGF2 secretion via ELISA. The effects of FGF signaling attenuation on OS cell pro-tumorigenic properties were evaluated by colorimetric proliferation assay and scratch migration assay. The effects of FGF signaling blockade with pan-FGFR inhibitor BGJ398 on OS cell differentiation were evaluated with Alizarin Red staining and quantification, alkaline phosphatase (ALP) bio-activity, and quantitative real time reverse transcription polymerase chain reaction (qRT-PCR) for osteogenic genes alkaline phosphatase (ALP), osterix(OSTX), osteonectin (OSN), and runt-related transcription factor 2 (RUNX2). Circulating FGF2 levels were quantified in the plasma of dogs with naturally occurring OS (determined to be osteoblastic or osteolytic based on relative bone mineral density obtained via DEXA scan)and healthy controls via ELISA.FGFR gene expression was noted in OS cell lines. FGF2 secretion was identified in all cell lines with secretion noted in a clear cell density-dependent manner in 2 of 3 cell lines. FGFR signaling attenuation inhibited OS cell migration while not affecting cell proliferation. FGFR signaling blockade increased differentiation in 1 of 2 cell lines evaluated, with a trend toward increased differentiation in the other cell line. The presence of naturally-occurring OS did not alter the level of circulating FGF2 in dogs. This study is the first to identify a link between FGF signaling attenuation and OS cell differentiation and migration in a cell line-dependent manner.These findings indicate that FGF blockade could be beneficial in some dogs with OS.