RESUMEN
BACKGROUND: Gastric cancer (GC) is a common malignancy with high incidence and mortality, and its pathogenesis involves the regulation of circular RNAs (circRNAs). However, the molecular mechanism of circTMEM87A in GC malignant progression is uncertain. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expressions of circTMEM87A, miR-1276, and solute carrier family 7 membrane 11 (SLC7A11). Western blot was applied to detect protein expression levels of EMT-related proteins (vimentin and E-cadherin) and SLC7A11. Cell counting kit-8 assay (CCK8) and thymidine analog 5-ethynyl-2'-deoxyuridine (EdU) were performed to assess cell proliferation. Apoptosis was investigated using flow cytometry. Transwell assay and wound healing assay were carried out to examine the migration of MKN-7 and AGS cells. The Cellular ROS Assay Kit, Iron Assay Kit, and GSH/GSSG Ratio Detection Assay Kit were utilized to monitor lipid ROS level, iron level, and GSH/GSSG ratio, respectively. The interaction between miR-1276 and circTMEM87A or SLC7A11 was investigated using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. A xenograft mouse model was constructed to explore the function of circTMEM87A in tumor formation in vivo. RESULTS: CircTMEM87A and SLC7A11 were upregulated, while miR-1276 was downregulated in GC tissues and cells. Knockdown of circTMEM87A suppressed the proliferation and migration and promoted apoptosis and ferroptosis of GC cells. CircTMEM87A served as a sponge for miR-1276, and miR-1276 inhibitor relieved the circTMEM87A knockdown-induced effects on GC cell phenotypes. Similarly, SLC7A11, a downstream gene of miR-1276, rescued miR-1276 overexpression-induced effects on GC cell function. Furthermore, circTMEM87A knockdown inhibited GC cell tumor phenotypes in vivo. CONCLUSION: CircTMEM87A promoted the proliferation and migration and inhibited apoptosis and ferroptosis of GC cells by increasing SLC7A11 expression through binding to miR-1276.
Asunto(s)
MicroARNs , Neoplasias Gástricas , Humanos , Animales , Ratones , Neoplasias Gástricas/genética , Disulfuro de Glutatión , Especies Reactivas de Oxígeno , Carcinogénesis/genética , Transformación Celular Neoplásica , Proliferación Celular/genética , Modelos Animales de Enfermedad , Hierro , MicroARNs/genética , Línea Celular Tumoral , Sistema de Transporte de Aminoácidos y+/genéticaRESUMEN
BACKGROUND: Our previous study has demonstrated that knockdown of activated ERK1/2(pERK1/2) sensitizes pancreatic cancer cells to chemotherapeutic drug gemcitabine (Gem) treatment. However, the details of this survival mechanism remain undefined. It has also shown that Bcl-2 confers resistance and Bax sensitizes to gemcitabine-induced apoptosis in pancreatic cancer cells. Furthermore, the extracellular signaling-regulated kinase (ERK) signaling pathway regulates Bcl-2/Bax expression ratio. We therefore tested the hypothesis that pancreatic cancer cells are resistant to gemcitabine and this resistance is due to activation of ERK1/2 and subsequent upregulation of Bcl-2 and downregulation of Bax. METHODS: Pancreatic cancer cell BXPC-3 was used in the study. The effect of pharmacological inhibition of ERK1/2 on resistance of pancreatic cancer cells to apoptosis induced by treatment with gemcitabine was analyzed. The following methods were utilized: TUNEL and ELISA were used to detect apoptosis. Western blot was used to detect the protein expression. RESULTS: Gemcitabine treatment enhanced the activity of ERK1/2 in the BXPC-3 cells. Inhibition of the ERK1/2 by PD98059 could downregulate Bcl-2 and upregulate Bax and was associated with restoration of sensitivity to gemcitabine in BXPC-3 cells. Depletion of endogenous Bcl-2 expression by specific small interfering RNA transfection significantly increased gemcitabine-induced cell apoptosis. Combined treatment with PD98059 and Bax siRNA transfection could decrease gemcitabine-induced ERK1/2 and Bax activation, which subsequently resulted in decreased apoptosis. CONCLUSIONS: The upregulation of ERK1/2-dependent Bcl-2 and downregulation of ERK1/2-dependent Bax can protect human pancreatic cancer cells from gemcitabine-induced apoptosis. Targeting the ERK1/2-Bax/Bcl-2 pathway may in part lead to sensitization of pancreatic cancer to gemcitabine.
Asunto(s)
Apoptosis/efectos de los fármacos , Desoxicitidina/análogos & derivados , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteína Quinasa 1 Activada por Mitógenos/antagonistas & inhibidores , Proteína Quinasa 3 Activada por Mitógenos/antagonistas & inhibidores , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Adenocarcinoma/tratamiento farmacológico , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Antimetabolitos Antineoplásicos/farmacología , Western Blotting , Proliferación Celular/efectos de los fármacos , Desoxicitidina/farmacología , Humanos , Proteína Quinasa 1 Activada por Mitógenos/genética , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/genética , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Neoplasias Pancreáticas/tratamiento farmacológico , Neoplasias Pancreáticas/metabolismo , Fosforilación/efectos de los fármacos , ARN Interferente Pequeño/genética , Células Tumorales Cultivadas , GemcitabinaRESUMEN
The present study aimed to determine the expression levels and biological functions of microRNA-202 (miR-202) in patients with esophageal squamous cell carcinoma (ESCC). A total of 60 patients with ESCC and 30 healthy individuals were enrolled and reverse transcription-quantitative polymerase chain reaction was performed to measure the expression levels of miR-202. In order to investigate the effects of miR-202 expression levels on the proliferative, migratory and invasive abilities of ESCC cells, methylthiazolyl-tetrazolium bromide proliferation, in vitro scratch and Transwell® chamber assays were performed. Expression levels of miR-202 were significantly decreased in the peripheral blood of patients with ESCC, which is associated with the degree of cell differentiation and lymph node metastasis (P<0.05). Following miR-202 transfection, cell proliferation was significantly inhibited (P<0.05). Cell migration and invasion was also significantly inhibited by miR-202 transfection (P<0.05). The results of the present study demonstrated that the expression of miR-202 inhibited the proliferation, migration and invasion of ESCC cells. Furthermore, low expression levels of miR-202 were detected in the peripheral blood of patients with ESCC, which is associated with the development, invasion and metastasis of ESCC.
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Favourable conditions for the existence of the Griffiths phase in the La0.85Ca0.15MnO3 compound are experimentally investigated in terms of electronic and lattice structure by temperature-dependent x-ray absorption spectroscopy, valence band photoemission spectroscopy, and x-ray diffraction experiments. The chemical shifts of Mn L-edge and O K-edge x-ray absorption lines in the Griffiths phase are understood to be related to the hybridization between Mn 3d and O 2p states instead of the variation of Mn valence states. Valence band spectra also indicate that the hybridization of O 2p with Mn 3d is enhanced in the Griffiths phase. From a 2D diluted Ising ferromagnet model, this hybridization between Mn 3d and O 2p orbitals surely enhances the Griffiths phase feature.