Riluzole-induced apoptosis in osteosarcoma is mediated through Yes-associated protein upon phosphorylation by c-Abl Kinase

Abstract

Our lab has previously demonstrated Riluzole to be an effective drug in inhibiting proliferation and inducing apoptosis in both human and mouse osteosarcoma. Yes-associated protein is a transcription co-activator, known to be involved in cell proliferation or apoptosis depending on its protein partner. In the present study we investigated the role of YAP in apoptosis in osteosarcoma, we hypothesized that YAP may be activated by Riluzole to induce apoptosis in osteosarcoma. By knocking down the expression of YAP, we have demonstrated that Riluzole failed to induce apoptosis in YAP deficient osteosarcoma cells. Riluzole caused translocation of YAP from the cytoplasm to the nucleus, indicating YAP’s role in apoptosis. Both Riluzole-induced phosphorylation of YAP at tyrosine 357 and Riluzole-induced apoptosis were blocked by inhibitors of c-Abl kinase. In addition, knockdown of c-Abl kinase prevented Riluzole-induced apoptosis in LM7 cells. We further demonstrated that Riluzole promoted interaction between YAP and p73, while c-Abl kinase inhibitors abolished the interaction. Subsequently, we demonstrated that Riluzole enhanced activity of the Bax promoter in a luciferase reporter assay and enhanced YAP/p73 binding on endogenous Bax promoter in a ChIP assay. Our data supports a novel mechanism in which Riluzole activates c-Abl kinase to regulate pro-apoptotic activity of YAP in osteosarcoma.

Delivery of mGluR5 siRNAs by Iron Oxide Nanocages by Alternating Magnetic Fields for Blocking Proliferation of Metastatic Osteosarcoma Cells

“…Previously, it has been reported that osteosarcoma secretes glutamate and the metabotropic glutamate receptor (mGluR) is highly expressed in osteosarcoma [ 15 , 17 , 18 , 42 ]. mGluR5 is especially involved in glutamate signaling for cell growth; therefore, knockdown of mGluR5 expression in osteosarcoma cells can disrupt the proliferation of the cells [ 15 , 17 , 18 , 43 ].…”

“…Previously, it has been reported that osteosarcoma secretes glutamate and the metabotropic glutamate receptor (mGluR) is highly expressed in osteosarcoma [ 15 , 17 , 18 , 42 ]. mGluR5 is especially involved in glutamate signaling for cell growth; therefore, knockdown of mGluR5 expression in osteosarcoma cells can disrupt the proliferation of the cells [ 15 , 17 , 18 , 43 ]. In this study, we demonstrated the reduction of mGluR5 expression in osteosarcoma by delivering mGluR5 siRNAs via IO-nanocages vehicles, and we observed the inhibition of cell growth when mGluR5 expression was silenced as AMFs were applied.…”

“…The stability of siRNAs, regulation of post-transcriptional gene expression, and ability to distinguish between normal and tumor tissues are potential advantages of using siRNAs as therapeutic agents [ 13 , 14 ]. Osteosarcoma is known to secrete glutamate and express glutamate metabolic receptors that involve autocrine/paracrine glutamate signaling to promote tumor growth [ 15 , 16 , 17 ]. Our previous studies have shown that type 5 metabotropic glutamate receptor (mGluR5) is expressed in LM7 cells.…”

“…Our previous studies have shown that type 5 metabotropic glutamate receptor (mGluR5) is expressed in LM7 cells. Knockdown of mGluR5 expression using Lentivirus ShRNA in the LM7 cells prohibited the formation of colonies, suggesting that mGluR5 plays an important role in glutamate-dependent proliferation of osteosarcoma cells [ 15 , 17 , 18 ]. Regulating mGluR5 expression in the cells that affect the tumor growth by delivering siRNA would be beneficial, since we can improve target-specific treatment and avoid cancer recurrence and tumor progression that is caused by drug resistance occurring in the tumor microenvironment.…”

Implications of a Neuronal Receptor Family, Metabotropic Glutamate Receptors, in Cancer Development and Progression

“…Several investigators have reported on the anti-proliferative activities of riluzole in gliomas; however, no further studies have been performed to examine if, in the presence of riluzole, the cells exhibit DNA damage [ 72 , 73 , 74 ]. A recent report by Mahajan and colleagues demonstrated increased DNA damage in riluzole-treated osteosarcoma cells [ 75 ]. Furthermore, oxidative stress has been proposed to be a component of many neurodegenerative diseases; however, it is not known if in ALS or other neurodegenerative diseases, patients treated with riluzole show elevated levels of DNA damage [ 76 , 77 , 78 ].…”