RESUMEN
The mTOR pathway is a central control of cell growth, proliferation, metabolism, and survival, and is deregulated in most cancers. Cancer cells are addicted to increased activity of mTOR kinase-mediated signaling pathways, leading to numerous inhibitors of mTOR signaling in preclinic and clinical trials for cancer therapy. Phosphorus-containing sirolimus (FIM-A), which targets mTOR signaling, inhibits cancer cell growth in vitro. Here we report that FIM-A reduces the angiogenesis and proliferation of osteosarcoma both in vitro and in vivo. In cultured osteosarcoma cell lines, FIM-A inhibited cell proliferation and arrested cells in the G1 phase of the cell cycle, accompanied with reduction of VEGF and HIF-1alpha. With in vivo mouse osteosarcoma xenografts, FIM-A treatment resulted in the inhibition of mTORC1 signaling as demonstrated by the decreased phosphorylation of p70S6K1 and 4E-BP1. Consistent with this finding, FIM-A significantly decreased the average tumor volume, nuclei staining of PCNA, and the number of intratumoral microvessels. Our data demonstrated that targeting mTORC1 by FIM-A inhibited the growth of osteosarcoma in vitro and in vivo, providing the basis for further development of FIM-A as a therapy for osteosarcoma patients.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias Óseas/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Neovascularización Patológica/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico , Sirolimus/análogos & derivados , Inhibidores de la Angiogénesis/farmacología , Animales , Línea Celular Tumoral , Femenino , Humanos , Diana Mecanicista del Complejo 1 de la Rapamicina , Ratones , Ratones Endogámicos BALB C , Complejos Multiproteicos/antagonistas & inhibidores , Fósforo , Sirolimus/química , Sirolimus/farmacología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Transplantation of neural stem cells (NSCs) holds great potential for the treatment of spinal cord injury (SCI). However, transplanted NSCs poorly survive in the SCI environment. We injected NSCs into tibial nerve and transplanted tibial nerve into a hemisected spinal cord and investigated the effects of lithium chloride (LiCl) on the survival of spinal neurons, axonal regeneration, and functional recovery. Our results show that most of the transplanted NSCs expressed glial fibrillary acidic protein, while there was no obvious expression of nestin, neuronal nuclei, or acetyltransferase found in NSCs. LiCl treatment produced less macrosialin (ED1) expression and axonal degeneration in tibial nerve after NSC injection. Our results also show that a regimen of LiCl treatment promoted NSC differentiation into NF200-positive neurons with neurite extension into the host spinal cord. The combination of tibial nerve transplantation with NSCs and LiCl injection resulted in more host motoneurons surviving in the spinal cord, more regenerated axons in tibial nerve, less glial scar area, and decreased ED1 expression. We conclude that lithium may have therapeutic potential in cell replacement strategies for central nervous system injury due to its ability to promote survival and neuronal generation of grafted NSCs and reduced host immune reaction.
Asunto(s)
Cloruro de Litio/uso terapéutico , Células-Madre Neurales/fisiología , Células-Madre Neurales/trasplante , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/terapia , Animales , Antígenos CD/metabolismo , Antígenos de Diferenciación Mielomonocítica/metabolismo , Movimiento Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Femenino , Proteína Ácida Fibrilar de la Glía/metabolismo , Inmunohistoquímica , Degeneración Nerviosa/tratamiento farmacológico , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/terapia , Regeneración Nerviosa/efectos de los fármacos , Neurogénesis/efectos de los fármacos , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Ratas , Traumatismos de la Médula Espinal/metabolismo , Nervio Tibial/efectos de los fármacosRESUMEN
The current study was performed to evaluate the mechanisms and therapeutic effects of overexpressing neuroglobin (Ngb) on spinal cord injury (SCI). Adeno-associated virus (AAV) was injected in the T12 section 7 days before SCI. Animals were randomly divided into four groups: a sham group, a vehicle group, an AAV-EGFP group and an AAV-Ngb group. Recovery of hind limb locomotor function was determined during the 3-week post operation period by the Basso, Beattie and Bresnahan locomotor rating scale. At 24 h after SCI and at the end of the study, the segments of spinal cord, centered with the lesion site were harvested for histopathological analysis. Immunofluorescence was performed using antibodies to recognize neuN in the lesion sections. At 24 h after SCI, the spinal cord tissue samples were removed to analyze tissue concentrations of superoxide dismutase (SOD) and malondialdehyde (MDA). Apoptotic cells were assessed using a terminal deoxynucleotidyl transferase, dUTP nick end labeling (TUNEL) kit. The expression of bcl-2, bax, cytochrome c, and cleaved caspase-3, were determined by Western blot assay and immunostaining analysis. The results showed that animals overexpressing Ngb had significantly greater recovery of locomotor function, less neuronal loss and fewer apoptotic cells. In addition, overexpressing Ngb significantly increased bcl-2 expression and SOD level, decreased bax expression, attenuated the release of cytochrome c from mitochondria to the cytosol fraction, and reduced the activity of caspase-3 and MDA level after SCI. These findings suggest, that overexpressing Ngb can significantly improve the recovery of locomotor function. This neuroprotective effect may be associated with the inhibition of neural apoptosis via the mitochondrial pathway.