RESUMEN
Many studies have shown that mesenchymal stromal cells (MSCs) and their secreted factors may modulate the biology of tumor cells. However, how these interactions happen in vivo remains unclear. In the present study, we investigated the effects of rat adipose-derived stromal cells (ADSCs) and their conditioned medium (ADSC-CM) in glioma tumor growth and malignancy in vivo. Our results showed that when we co-injected C6 cells plus ADSCs into the rat brains, the tumors generated were larger and the animals exhibited shorter survival, when compared with tumors of the animals that received only C6 cells or C6 cells pre-treated with ADSC-CM. We further showed that the animals that received C6 plus ADSC did not present enhanced expression of CD73 (a gene highly expressed in ADSCs), indicating that the tumor volume observed in these animals was not a mere consequence of the higher density of cells administered in this group. Finally, we showed that the animals that received C6 + ADSC presented tumors with larger necrosis areas and greater infiltration of immune cells. These results indicate that the immunoregulatory properties of ADSCs and its contribution to tumor stroma can support tumor growth leading to larger zones of necrosis, recruitment of immune cells, thus facilitating tumor progression. Our data provide new insights into the way by which ADSCs and tumor cells interact and highlight the importance of understanding the fate and roles of MSCs in tumor sites in vivo, as well as their intricate crosstalk with cancer cells.
Asunto(s)
Glioblastoma , Tejido Adiposo/metabolismo , Animales , Medios de Cultivo Condicionados/metabolismo , Medios de Cultivo Condicionados/farmacología , Glioblastoma/genética , Glioblastoma/terapia , Necrosis , Ratas , Células del Estroma/metabolismoRESUMEN
BACKGROUND: Gliomas are the most aggressive malignant tumors of the central nervous system. The diphenyl diselenide [(PhSe)2] is an organoselenium compound that has multiple pharmacological properties. Previous reports showed that (PhSe)2 nanoencapsulation potentiates its in vitro antitumoral action and reduces its toxicity. OBJECTIVE: In this sense, the current study was designed to further evaluate the (PhSe)2 antitumoral effect by a set of in vitro techniques using a glioma cell line as well as by an animal model of gliobastoma. METHODS: For the in vitro tests, the cell viability, propidium iodide uptake and nitrite levels of rat glioma C6 cells were determined after incubation with free (PhSe)2 or (PhSe)2-loaded nanocapsules (NC). The glioblastoma model was induced by implantation of C6 glioma cells in the right striatum of rats. Following, animals were submitted to a repeated intragastric administration treatment with (PhSe)2 or NC (PhSe)2 (1â¯mg/kg/day for 15 days) to assess the possible antitumor effect. MAIN FINDINGS: Both compound forms decreased the C6 glioma cells viability without causing any effect in astrocytes cells (healthy control). Importantly, the NC (PhSe)2 had superior cytotoxic effect than its free form and increased the nitrite content. Independent of the (PhSe)2 forms, the intragastric treatment reduced brain tumor size and caused neither alteration in the plasma renal and hepatic markers of function nor in the parameters of oxidative balance in brain, liver and kidneys. PRINCIPAL CONCLUSIONS: The (PhSe)2 nanoencapsulation improved its cytotoxic effect against C6 glioma cells and both compound forms attenuated the tumor development.