Rhabdomyosarcoma (RMS) is a muscle-derived tumor. In both pre-clinical and clinical studies Temozolomide (TMZ) has been recently tested against RMS; however, the precise mechanism of action of TMZ in RMS remains unclear. Here we demonstrate that TMZ decreases the cell viability of the RH30 RMS and C2C12 cell line, where cells display evidence of mitochondrial outer membrane permeability. Interestingly, the C2C12 mouse myoblast line was relatively more resistant to TMZ-induced apoptosis. Moreover, we observed that TMZ activated biochemical and morphological markers of autophagy in both cell lines. Autophagy inhibition in both RH30 and C2C12 cells significantly increased TMZ-induced cell death. In RH30 cells, TMZ increased Mcl-1 and Bax protein expression compared to corresponding time match controls while in C2C12 Mcl-1, Bcl-2, Bcl-XL, and Bax protein expression were not changed. Baf-A1 co-treatment with TMZ significantly decrease Mcl-1 expression compared to TMZ while increase Bax expression in C2C12 cells (Bcl2 and Bcl-XL do not significantly change in Baf-A1/TMZ co-treatment). Using a three-dimensional (3D) C2C12 and RH30 culture model we demonstrated that TMZ is significantly more toxic in RH30 cells (live/dead assay). Additionally, we have observed in our 3D culture model that TMZ induced both apoptosis (cleavage of PARP) and autophagy (LC3-puncta and localization of LC3/p62). Therefore, our data demonstrate that TMZ induces simultaneous autophagy and apoptosis in both RH30 and C2C12 cells in 2D and 3D culture model, where RH30 cells are more sensitive to TMZ-induced death. Furthermore, autophagy serves to protect RH30 cells from TMZ-induced death.
Current treatment strategies for Glioblastoma (GBM)-including surgery, radiotherapy, and chemotherapy with oral administration of temozolomide (TMZ)-still lead to poor survival rates, making the development of more effective therapeutic methods an urgent need. This study presents a new approach for the treatment of GBM patients using a 3D-printed hydrogel-based mesh (GlioMesh), loaded with TMZ-releasing microparticles, that is capable of delivering TMZ over several weeks at the tumor site. Given the challenges associated with loading the amphiphilic TMZ in polymeric substrates, a novel encapsulation strategy is developed using an oil-in-oil emulsion method that improves the encapsulation efficiencies of TMZ in poly(lactic-co-glycolic acid) (PLGA) from <7% to about 61%. The cytotoxic effects of GlioMesh on GBM cells are evaluated in vitro by investigating the resultant levels of DNA break, autophagic activity, and mitochondrial damage. It is shown that GlioMesh produces significantly higher susceptibility to the drug in comparison with free TMZ by maintaining the level of autophagic activity and inducing larger degrees of mitochondrial damage. Sustained delivery of TMZ holds promise for suppressing chemoresistance to TMZ that is normally developed in GBM cells in systemic administration of the drug due to the induction of autophagy.
This is a first attempt to use an averaged MSE error surface (obtained from the prediction of different patients' tumor trajectories) to determine the parameters of a generalized neural network. This network could be deployed as a plug-and-play predictor for tumor trajectory during treatment delivery, eliminating the need for optimizing individual networks with pretreatment patient data.
Statins are some of the most widely used drugs worldwide, but one of their major side effects is myotoxicity. Using mouse myoblast (C2C12) and human alveolar rhabdomyosarcoma cell lines (RH30) in 2-dimensional (2D) and 3-dimensional (3D) culture, we investigated the mechanisms of simvastatin's myotoxicity. We found that simvastatin significantly reduced cell viability in C2C12 cells compared to RH30 cells. However, simvastatin induced greater apoptosis in RH30 compared to C2C12 cells. Simvastatin-induced cell death is dependent on Geranylgeranyl pyrophosphate (GGPP) in C2C12 cells, while in RH30 cells it is dependent on both Farnesyl pyrophosphate (FPP) and GGPP. Simvastatin inhibited autophagy flux in both C2C12 and RH30 cells and inhibited lysosomal acidification in C2C12 cells, while autophagy inhibition with Bafilomycin-A1 increased simvastatin myotoxicity in both cell lines. Simvastatin induced more cell death in RH30 cells compared to C2C12 in 3D culture model with similar effects on autophagy flux as in 2D culture. Overall our results suggest that simvastatin-induced myotoxicity involves both apoptosis and autophagy, where autophagy serves a pro-survival role in both cell lines. The sensitivity to simvastatin myotoxicity is different in 2D versus 3D culture, demonstrating that the cellular microenvironment is a critical factor in regulating simvastatininduced cell death in myoblasts.
Systemic hypoxia is a common element in most perinatal emergencies and is a known driver of Bnip3 expression in the neonatal heart. Bnip3 plays a prominent role in the evolution of necrotic cell death, disrupting ER calcium homeostasis and initiating mitochondrial permeability transition (MPT). Emerging evidence suggests a cardioprotective role for the prostaglandin E1 analog misoprostol during periods of hypoxia, but the mechanisms for this protection are not completely understood. Using a combination of mouse and cell models, we tested if misoprostol is cardioprotective during neonatal hypoxic injury by altering Bnip3 function. Here we report that hypoxia elicits mitochondrial-fragmentation, MPT, reduced ejection fraction, and evidence of necroinflammation, which were abrogated with misoprostol treatment or Bnip3 knockout. Through molecular studies we show that misoprostol leads to PKA-dependent Bnip3 phosphorylation at threonine-181, and subsequent redistribution of Bnip3 from mitochondrial Opa1 and the ER through an interaction with 14-3-3 proteins. Taken together, our results demonstrate a role for Bnip3 phosphorylation in the regulation of cardiomyocyte contractile/metabolic dysfunction, and necroinflammation. Furthermore, we identify a potential pharmacological mechanism to prevent neonatal hypoxic injury.
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