RESUMEN

INTRODUCTION: Gliomas are the most seen tumours in adults in the central nervous system, and high grade of gliomas cause the worse prognose of patients with a shorter survival period. Ubiquitin-specific protease 38 (USP38) has been regarded as the negative regulator of type I interferon signalling; it regulates the ubiquitination process of TANK binding kinase 1 (TBK1). Further study revealed that USP38 also stabilizes the protein lysine-specific histone demethylase 1A (LSD1) via cleaving the ubiquitin chain. However, the effect of USP38 in colorectal cancer was not fully understood. MATERIAL AND METHODS: USP38 overexpression and knockdown vector were constructed using the molecular clone method. The viability rate of U-87MG and U-138MG cells were detected using the Cell Counting Kit-8 (CCK-8) method.The expression and secretion of metastasis-related molecules were detected using the qPCR and ELISA method. The expression of metastasis-related molecules and JAK2/STAT3 signalling pathway was detected using western blotting analysis. RESULTS: In this study, we firstly constructed a USP38 overexpression and inhibition model in 2 cell lines and found that overexpression of USP38 inhibits the viability rate and migration ability of glioma cells. We further noticed that elevated expression of USP38 reduced the expression and secretion of cell adhesion-related molecules with the elevation in expression of pro-apoptotic proteins, and these effects might be mediated by inhibition of JAK2/STAT3 signalling pathway as USP38 is the upstream regulator of STAT3 and inhibition of cellular adhesion process. CONCLUSIONS: USP38 might be a new therapeutic target for glioma.

Asunto(s)

Glioma , Proteasas Ubiquitina-Específicas , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Glioma/genética , Humanos , Janus Quinasa 2 , Metástasis de la Neoplasia , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Proteasas Ubiquitina-Específicas/genética , Proteasas Ubiquitina-Específicas/metabolismo , Ubiquitinación

RESUMEN

INTRODUCTION: Bufalin is a component of Chinese traditional medicine, Chansu, which is reported to induce cell death among various kinds of tumors. Apoptosis evasion is a common problem of cancer treatment. MATERIALS AND METHODS: The proliferation of U-87 and U-373 treated by bufalin combined with or without apoptosis inhibitor was detected by MTT assay. The protein levels related to apoptosis and necroptosis were measured by Western blotting. Immunoprecipitation (IP) was applied for monitoring the formation of necrosome. The gene knockdown by CRISPR/Cas9 was applied to determine the roles of the proteins in apoptosis and necroptosis. RESULTS: In this study, we found that bufalin could induce apoptosis or necroptosis when U-87 and U-373 escaped from apoptosis. Bufalin triggered cell death by upregulating tumor necrosis factor (TNF) -α, TNF receptor 1 (TNFR1) and receptor-interacting protein 1 (RIPK1). Antagonizing cellular inhibitor of apoptosis 1 (cIAP1) and cIAP2 were also contributory. Caspase-8 activation led to apoptosis. When caspase-8 was functionally lost, necrosome consisted of RIPK1, receptor-interacting protein 3 (RIPK3) and mixed lineage kinase domain-like protein (MLKL) formed and necroptosis happened. The knockdown of above genes or the drug treatment confirmed the mechanism of bufalin-induced cell death. Cytotoxicity of bufalin to caspase-8 knockdown cell lines made control cell lines more sensitive to bufalin in their mixture. DISCUSSION: The cytotoxicity of bufalin to U-87 and U-373 was by inducing apoptosis or necroptosis when they were sensitive to apoptosis or not. The results indicated that seeking for treatments that could induce apoptosis and necroptosis was a good solution for the tumor evasion of apoptosis.