RESUMEN
Multidrug resistance (MDR) significantly restricts the clinical efficacy of gastric cancer (GC) chemotherapy, and it is critical to search novel targets to predict and overcome MDR. Leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) has been proved to be correlated with drug resistance in several cancers. The present study revealed that LRIG1 was overexpressed in chemosensitive GC tissues and decreased expression of LRIG1 predicted poor survival in GC patients. We observed that upregulation of LRIG1 enhanced chemosensitivity in GC cells. Interestingly, miR-20a, which was overexpressed in GC MDR cell lines and tissues, was identified to regulate LRIG1 expression by directly targeting its 3' untranslated region. We also found that inhibition of miR-20a suppressed GC MDR, and upregulation showed opposite effects. Moreover, we demonstrated that the miR-20a/LRIG1 axis regulated GC cell MDR through epidermal growth factor receptor (EGFR)-mediated PI3K/AKT and MAPK/ERK signaling pathways. Finally, LRIG1 expression in human GC tissues is inversely correlated with miR-20a and EGFR. Taken together, the newly identified miR-20a/LRIG1/EGFR link provides insight into the MDR process of GC, and targeting this axis represents a novel potential therapeutic strategy to block GC chemoresistance.
Asunto(s)
Regulación hacia Abajo/genética , Resistencia a Múltiples Medicamentos/genética , Resistencia a Antineoplásicos/genética , Leucina/genética , Glicoproteínas de Membrana/genética , MicroARNs/genética , Neoplasias Gástricas/genética , Regiones no Traducidas 3'/genética , Línea Celular Tumoral , Proliferación Celular/genética , Receptores ErbB/genética , Regulación Neoplásica de la Expresión Génica/genética , Humanos , Fosfatidilinositol 3-QuinasasRESUMEN
Epigenetic changes play significant roles in cancer development. UHRF1, an epigenetic regulator, has been shown to be overexpressed and to coordinate tumor suppressor gene (TSG) silencing in several cancers. In a previous study, we found that UHRF1 promoted gastric cancer (GC) invasion and metastasis. However, the role and underlying mechanism of UHRF1 in GC carcinogenesis remain largely unknown. In the present study, we investigated UHRF1 expression and function in GC proliferation and explored its downstream regulatory mechanism. The results demonstrated that UHRF1 overexpression was an independent and significant predictor of GC prognosis. Downregulation of UHRF1 suppressed GC proliferation and growth in vitro and in vivo, and UHRF1 upregulation showed opposite effects. Furthermore, downregulation of UHRF1 reactivated 7 TSGs, including CDX2, CDKN2A, RUNX3, FOXO4, PPARG, BRCA1 and PML, via promoter demethylation. These results provide insight into the GC proliferation process, and suggest that targeting UHRF1 represents a new therapeutic approach to block GC development.
Asunto(s)
Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Genes Supresores de Tumor , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Anciano , Animales , Proteínas Potenciadoras de Unión a CCAAT/genética , Línea Celular Tumoral , Metilación de ADN , Epigénesis Genética , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Estimación de Kaplan-Meier , Masculino , Ratones Endogámicos BALB C , Ratones Desnudos , Persona de Mediana Edad , Pronóstico , Regiones Promotoras Genéticas , Neoplasias Gástricas/mortalidad , Ubiquitina-Proteína Ligasas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Previous studies have indicated that heat shock protein 27 (HSP27) had high correlation with the development and progression in several tumors. However, the roles of HSP27 in esophageal squamous cell carcinoma (ESCC) were uncertain. The aim in this study is to investigate the potential roles of HSP27 in the metastasis of ESCC. The expression of HSP27 in ESCC tissues and four human esophageal cancer cell lines were examined by immunohistochemistry and Western blotting, respectively. Wound healing assays, transwell assays, and in vivo assays were used to identify the differences of metastasis potential between normal and HSP27 overexpressed cells. HSP27 expression was downregulated in cancer tissue compared to the matched normal tissue. And the positive staining was mainly located in the cytoplasm. Statistical analyses showed that the expression of HSP27 in ESCC was significantly correlated with the tumor differentiation (P = 0.023), the patient's TNM stage (P = 0.013), lymph metastasis (P = 0.020), and distant metastasis (P = 0.017). HSP27 expression was significantly lower in highly metastatic cells than the less ones. The metastatic potentials of EC9706-H and EC109-H cells were higher than EC9706-L and EC109-L cells. In vitro and in vivo assays showed that overexpression of HSP27 in highly metastatic cells dramatically decreased their metastatic capacity. This study indicated that the expression level of HSP27 may be inversely correlated with the metastasis behavior of ESCC, and HSP27 may play an important role in this progression. HSP27 may be a potential molecular target for the therapy and prognosis of patients with ESCC.