Blocking Signaling at the Level of GLI Regulates Downstream Gene Expression and Inhibits Proliferation of Canine Osteosarcoma Cells

Abstract

The Hedgehog-GLI signaling pathway is active in a variety of human malignancies and is known to contribute to the growth and survival of human osteosarcoma cells. In this study, we examined the expression and regulation of GLI transcription factors in multiple canine osteosarcoma cell lines and analyzed the effects of inhibiting GLI with GANT61, a GLI-specific inhibitor. Compared with normal canine osteoblasts, real-time PCR showed that GLI1 and GLI2 were highly expressed in two out of three cell lines and correlated with downstream target gene expression of PTCH1and PAX6. Treatment of canine osteosarcoma cells with GANT61 resulted in decreased expression of GLI1, GLI2, PTCH1, and PAX6. Furthermore, GANT61 inhibited proliferation and colony formation in all three canine osteosarcoma cell lines. The finding that GLI signaling activity is present and active in canine osteosarcoma cells suggests that spontaneously arising osteosarcoma in dogs might serve as a good model for future preclinical testing of GLI inhibitors.

Sonic Hedgehog Signaling Affected by Promoter Hypermethylation Induces Aberrant Gli2 Expression in Spina Bifida

“…Taking all these findings into account, we speculate that the epigenetic silencing of gli2 by hypermethylation is an important early event in the course of incomplete closure of the neural tube. GLI2 functions downstream of the Shh pathway and targets gli1 and ptch1, and a high level of GLI protein expression is often indicative of activated Shh signaling [27]. The present results found that inhibition of gli2 expression was accompanied by the decreased expression of gli1 but not ptch1, which is considered to be a repressor of the Shh pathway.…”

BMI1 Is Expressed in Canine Osteosarcoma and Contributes to Cell Growth and Chemotherapy Resistance

“…Three canine OSA cell lines (Abrams, D17, and Moresco) and three human OSA cell lines (U2OS, SAOS-2, and LM7) were used in this study. The Abrams and Moresco cell lines were a gift from Dr. Douglas Thamm and Colorado State University [ 14 – 17 ]. The D17 cell line is derived from an osteosarcoma lung metastasis and was purchased from ATCC (Manassas, VA, Cat# CCL-183) [ 16 , 17 ].…”

“…The Abrams and Moresco cell lines were a gift from Dr. Douglas Thamm and Colorado State University [ 14 – 17 ]. The D17 cell line is derived from an osteosarcoma lung metastasis and was purchased from ATCC (Manassas, VA, Cat# CCL-183) [ 16 , 17 ]. The U20S, SAOS-2, and LM7 cell lines were obtained from the MD Anderson Characterized Cell Line Core Facility [ 18 , 19 ].…”

Hedgehog signaling in the pathogenesis of neuro-oncology diseases

“…Кроме того PTCH1 является геном-мишенью для факторов транскрипции GLI, которые изменяют экспрессию мРНК PTCH1, что наблюдалось в 50% клеточных линий медуллобластомы и астроцитомы [15][16][17].…”