ABSTRACT
The aim of the present study was to assess the effects of sprouty homolog 2 (SPRY2) gene regulation by miR-21 on the occurrence, development and tumor metastasis in multiple myeloma (MM). The miR-21 expression lentiviral vector (LV)-anti-miR-21 and a liposome transfection method were used to screen MM cell lines with stable silent SPRY2. Real-time quantitative polymerase chain reaction (PCR) and western blot analyses were used to detect SPRY2 expression and miR-21 protein expression levels. An MTT assay was used to assess cell proliferation. Flow cytometry was used for analysis of cell cycle. A scratch test/wound healing assay was used to detect the cell migration ability. A Transwell assay was used to detect the cell invasion ability. Real-time quantitative PCR and western blot analysis showed that in the MM cell lines with high endogenous miR-21 expression (RPMI8226 and KM3), SPRY2 expression was significantly lower. Conversely, in the U266 cell line with low endogenous miR-21 expression, SPRY2 expression was significantly higher, and the gray values of miR-21 and SPRY2 protein in the respective cell lines showed statistically significant differences (P<0.01). Following transfection of U266 cells, the expression of miR-21 in the U266/LV-anti-miR21 lentiviral multiplicity of infection (MOI) 20 group and -MOI 40 group decreased significantly compared with that in the untransfected U266 group (P<0.05). SPRY2 protein expression in U266 cells transfected with miR-21 mimics was significantly reduced compared with that in the non-transfected (untreated) group and the negative control-transfected group (P<0.01). An MTT assay showed that compared with the non-transfected and negative control groups, the cell growth rate as well as the proliferation rate were significantly decreased in the transfection group 48, 72 and 96 h after transfection (P<0.01). Flow cytometric analysis showed that 48 and 72 h after transfection of U266 cells with miR-21 mimics, the apoptotic rates were (24.7 ± 1.97 and 38.6 ± 1.56%) in the U266 group, (27.3 ± 1.72 and 37.3 ± 1.59%) in the siRNA group and (12.7 ± 1.27 and 22.1 ± 1.63%) in the U266/miR-21 group. Compared with the two control groups, the apoptotic rate in the U266/miR-21 group was significantly decreased and the G0/G1 phase cell population was significantly reduced (P<0.05). Scratch experiments showed that the cell migration ability was significantly reduced in the transfection group 24 and 48 h after transfection (P<0.05). A Transwell invasion assay confirmed that the number of U266 cells which migrated through a Matrigel-covered polyphosphate membrane significantly decreased in the transfection group 24 and 48 h after transfection. The cell-penetrating ability was also significantly decreased (P<0.05). In conclusion, the downregulation of SPRY2 gene expression mediated by miR-21 promotes the proliferation and invasion of MM cells in vitro, suggesting that miR-21 may be a novel potential molecular therapeutic target in the treatment of MM.
Subject(s)
Intracellular Signaling Peptides and Proteins/metabolism , Membrane Proteins/metabolism , MicroRNAs/metabolism , Apoptosis , Cell Line, Tumor , Cell Movement , Cell Proliferation , Down-Regulation , Humans , Intracellular Signaling Peptides and Proteins/antagonists & inhibitors , Intracellular Signaling Peptides and Proteins/genetics , Membrane Proteins/antagonists & inhibitors , Membrane Proteins/genetics , MicroRNAs/antagonists & inhibitors , MicroRNAs/genetics , Multiple Myeloma/metabolism , Multiple Myeloma/pathology , Oligonucleotides, Antisense/metabolism , RNA Interference , RNA, Small Interfering/metabolism , Real-Time Polymerase Chain Reaction , TransfectionABSTRACT
The aim of the present study was to investigate the expression level of microRNA 21 (miR21) in the peripheral blood of patients with multiple myeloma (MM) and to investigate the correlation between miR21 and sprouty homolog 2 (SPRY2) gene expression levels in MM. A total of 30 patients with MM, 15 with monoclonal gammopathy of undetermined significance (MGUS) and 20 normal control (NC) outpatients were selected for the detection of miR21 and SPRY2 expression using reverse transcription-quantitative polymerase chain reaction. In addition, western blot analysis was performed to detect the expression of miR21 and SPRY2 in MM cell lines. The expression of miR21 in U266 cells following lipofectamine transfection of fluorescencelabeled miR21 mimic/inhibitor was observed using a fluorescence microscope and the expression level of SPRY2 in the miR21 mimic/inhibitortransfected U266 cells was detected using western blot analysis. The miR21 expression level in the circulating serum of the MM patient group was significantly higher (P<0.01) than that of the MGUS and NC groups. The MM cell lines with high endogenous miR21 expression exhibited an expression level of SPRY2 that was significantly lower than that in the MM cells with low endogenous miR21 expression. The transfection efficiency of fluorescencelabeled miR21 mimic/inhibitor was >90%. Compared with the miR21 expression level in untreated U266 cells (0.82±0.13), the expression level of miR21 was increased by 120.2fold in miR21 mimictransfected cells (98.6±14.2; P<0.001) and was decreased by 61.9% in the miR21 inhibitortransfected cells (0.37±0.06; P<0.05). The grayscale value of protein bands demonstrated that SPRY2 protein expression significantly decreased in miR21 mimictransfected U266 cells compared with that in the inhibitortransfected, siRNAtransfected and untreated cells (P<0.01). miR21 may represent a negative regulator involved in the downregulation of SPRY2 in MM. miR21 is closely associated with the pathogenesis, progression and prognosis of MM and may thus be used as an indicator of poor MM prognosis.
Subject(s)
Gene Expression Regulation, Neoplastic , Intracellular Signaling Peptides and Proteins/genetics , Membrane Proteins/genetics , MicroRNAs/genetics , Multiple Myeloma/genetics , Adult , Aged , Aged, 80 and over , Cell Line, Tumor , Female , Gene Expression , Humans , Intracellular Signaling Peptides and Proteins/metabolism , Male , Membrane Proteins/metabolism , MicroRNAs/blood , Middle Aged , Multiple Myeloma/pathology , Neoplasm Staging , TransfectionABSTRACT
We conducted the present meta-analysis of relevant cohort studies to evaluate whether promoter methylation of the high in normal-1 (HIN-1) gene contributes to breast cancer. The MEDLINE (1966 ~ 2013), Cochrane Library (Issue 12, 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), Web of Science (1945 ~ 2013), and Chinese Biomedical (CBM) (1982 ~ 2013) databases were searched without any language restrictions. Meta-analyses were conducted using Stata software (version 12.0; Stata Corporation, College Station, TX, USA). Crude odds ratios (ORs) with their 95 % confidence interval (CI) were calculated. Nine clinical cohort studies that enrolled a total of 693 breast cancer patients were included in the meta-analysis. The results of our meta-analysis demonstrated that HIN-1 methylation frequency in cancer tissue was significantly higher than that of normal and benign tissues (cancer tissue vs. normal tissue: OR = 52.60, 95 % CI = 33.77 ~ 81.92, P < 0.001; cancer tissue vs. benign tissue: OR = 2.38, 95 % CI = 1.53 ~ 3.70, P < 0.001; respectively). Ethnicity-stratified analysis indicated that HIN-1 promoter methylation was correlated with the pathogenesis of breast cancer among both Asians and Caucasians (all P < 0.05). Our findings provide empirical evidence that aberrant HIN-1 promoter methylation may contribute to the pathogenesis of breast cancer. Thus, aberrant HIN-1 promoter methylation could be an independent and important biomarker used in predicting the prognosis and progression of breast cancer.