RESUMO
BACKGROUND: As an oncogene, long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) can promote tumor metastasis. Hyperexpression of MALAT1 has been observed in many malignant tumors, including hepatocellular carcinoma (HCC). However, the role and mechanism of MALAT1 in HCC remain unclear. METHODS: Thirty human HCC and paracancerous tissue specimens were collected, and the human hepatoma cell lines Huh7 and HepG2 were cultured according to standard methods. MALAT1 and Snail family zinc finger (Slug) expression were measured by real-time PCR, immunohistochemistry, and western blotting. Luciferase reporter assay and RNA immunoprecipitation (RIP) assay verified the direct interaction between miR-124-3p and Slug(SNAI2) or MALAT1. Wound healing and transwell assays were performed to examine invasion and migration, and a subcutaneous tumor model was established to measure tumor progression in vivo. RESULTS: MALAT1 expression was upregulated in HCC tissues and positively correlated with Slug expression. MALAT1 and miR-124-3p bind directly and reversibly to each other. MALAT1 silencing inhibited cell migration and invasion. miR-124-3p inhibited HCC metastasis by targeting Slug. CONCLUSIONS: MALAT1 regulates Slug through miR-124-3p, affecting HCC cell metastasis. Thus, the MALAT1/miR-124-3p/Slug axis plays an important role in HCC.
Assuntos
Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , MicroRNAs/genética , RNA Longo não Codificante/genética , Fatores de Transcrição da Família Snail/genética , Adulto , Idoso , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Técnicas de Silenciamento de Genes , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Pessoa de Meia-Idade , Metástase Neoplásica , Estadiamento de Neoplasias , Prognóstico , Interferência de RNA , Curva ROC , Fatores de Transcrição da Família Snail/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Gastric cancer is the fourth most common cancer type and the second leading cause of cancerassociated mortality worldwide. Metastasis is a crucial feature of its progression. DNA methylation provides a key epigenetic signature in the epigenetic regulation pathway, and is implicated in transcriptional regulation. CpG sites, which are associated with gene transcriptional activity, are underrepresented in the mammalian genome and tend to be clustered within CpG islands (CGIs) located in the vicinity of the transcription start sites of the majority of the proteincoding genes in humans. The DNA methylation inhibitor, decitabine (DAC), has been demonstrated to be active in hematological disorders. The majority of previous studies in cancer cells demonstrated that DAC inhibits cell proliferation and the motility of the cells. However, since demethylation across the entire genome alters the expression of a large number of genes, the effects of DAC in different tumor cell types are difficult to accurately predict. Neural precursor cellexpressed, developmentally downregulated (NEDD)41, a member of the NEDD4 family, which belongs to the E3ubiquitin ligase family, was reported to be highly expressed in a wide range of tumor types, and it activates the phosphoinositide 3kinase/Akt pathway by degrading phosphatase and tensin homolog. NEDD41 promotes the migration and invasion of glioma cells via the ubiquitination and subsequent degradation of cyclic nucleotideRas guanine nucleotide exchange factors (CNrasGEFs). In gastric cardia adenocarcinoma, NEDD41 acts as an exceptional prognostic biomarker. In the present study, DAC was revealed to promote the invasive properties of MGC803 gastric cancer cells. NEDD41 targeted the CNrasGEFmediated DAC invasionpromoting activity in MGC803 cells, and CGI methylation in neither the NEDD4 promoter nor the first intron was demonstrated to be associated with this effect. The results of the present study revealed that DAC exerts variable effects in different gastric cancer cell lines and may provide a reference for DAC administration in the clinic.
Assuntos
Azacitidina/análogos & derivados , Movimento Celular/efeitos dos fármacos , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Neoplasias Gástricas/genética , Ubiquitina-Proteína Ligases/genética , Regulação para Cima , Azacitidina/farmacologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Metilação de DNA/efeitos dos fármacos , Decitabina , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/fisiologia , Humanos , Ubiquitina-Proteína Ligases Nedd4 , Invasividade Neoplásica/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/fisiologiaRESUMO
OCT4 is an essential transcription factor for maintaining the self-renewal and the pluripotency of embryonic stem cells (ESCs). The human OCT4 gene can generate three mRNA isoforms (OCT4A, OCT4B and OCT4B1) by alternative splicing. OCT4A protein is a transcription factor for the stemness of ESCs, while the function of OCT4B isoforms remains unclear. Most types of cancer express a relatively low level of OCT4 protein, particularly the OCT4B isoforms. In the present study, we found that OCT4A and OCT4B mRNA were co-expressed in several types of tumor cell lines and tumor samples, and we demonstrated that OCT4B functioned as a non-coding RNA, modulating OCT4A expression in an miRNA-dependent manner [competing endogenous RNA (ceRNA) regulation] at the post-transcription level in the tumor cell lines. This is the first time that ceRNA regulation was observed among spliced isoforms of one gene, and may pave the way for identification of new targets for cancer treatment.
Assuntos
Fator 3 de Transcrição de Octâmero/genética , RNA Mensageiro/genética , RNA não Traduzido/genética , Processamento Alternativo/genética , Linhagem Celular Tumoral , Células HCT116 , Humanos , Isoformas de Proteínas/genética , Processamento Pós-Transcricional do RNA/genética , Fatores de Transcrição/genéticaRESUMO
The unique CX3C chemokine CX3CL1 and its cognate receptor CX3CR1 have been implicated in organ-specific metastasis of various types of tumors. Hypoxia, a common phenomenon in solid tumors, is associated with a malignant cancer phenotype. Previous studies have proved that hypoxia facilitates cancer cell metastasis through upregulation of specific chemokine receptors. We hypothesized that hypoxia could upregulate CX3CR1 expression and lead to an increased chemotactic response to CX3CL1 in prostate cancer cells. In the present study, we found that CX3CR1 expression was significantly increased in androgen-independent prostate cancer cells, including DU145, PC-3 and PC-3M, following exposure to hypoxia. This upregulation of CX3CR1 corresponded to a significant increase in migration and invasion of prostate cancer cells under hypoxic conditions, which was attenuated after knocking down CX3CR1 expression. In addition, we examined the possible role of HIF-1 and NF-κB in the process of hypoxia-induced CX3CR1 expression and hypoxia-mediated metastasis. Attenuation of HIF-1 and NF-κB transcriptional activity by siRNAs or pharmacological inhibitors, abrogated hypoxia-induced upregulation of CX3CR1, and also prevented the migration and invasion of DU145 cells under a hypoxic environment. In summary, our study demonstrated that HIF-1 and NF-κB are essential for hypoxia-regulated CX3CR1 expression, which is associated with increased migratory and invasive potential of prostate cancer cells. CX3CR1 signaling is a potential therapeutic target in the adjuvant treatment of prostate cancer.