Small Interfering RNA Methods Research Articles

Loss of function phenotype in chicken embryonic development using the small interfering RNA method

Loss of function phenotype in chicken embryonic development using the small interfering RNA method

Loss of function phenotype in chicken embryonic development using the small interfering RNA method

Introduction: The present study was based on the microinjection of lentiviruses into chicken embryos in the laboratory to demonstrate loss function phenotype in chicken embryonic development. Method: This study aims primarily to demonstrate that small interfering RNAs can act effectively on chicken embryonic development by decreasing function of the chicken sphingosine 1 phosphate receptor 1/endothelial differentiation gene 1 (S1P1/EDG-1) during embryogenesis. In addition, chicken embryo fibroblasts (CEF) were prepared, plasmid gene 3132/PLL3.7 was used with 2XHBS for transfection, virus titer was determined prior to virus microinjection into chicken embryos to see the loss-of-function phenotype. Results: The results obtained after viral microinjection showed that the function of S1P1/EDG-1 gene was progressively reduced from the second day of egg incubation until the fourth day. After the fifth day of incubation, loss of gene function was more marked by bleeding into the embryo sac.

Regulation of Molecular Targets in Osteosarcoma Treatment.

The most prevalent malignant bone tumor, osteosarcoma, affects the growth plates of long bones in adolescents and young adults. Standard chemotherapeutic methods showed poor response rates in patients with recurrent and metastatic phases. Therefore, it is critical to develop novel and efficient targeted therapies to address relapse cases. In this regard, RNA interference technologies are encouraging options in cancer treatment, in which small interfering RNAs regulate the gene expression following RNA interference pathways. The determination of target tissue is as important as the selection of tissue-specific promoters. Moreover, small interfering RNAs should be delivered effectively into the cytoplasm. Lentiviral vectors could encapsulate and deliver the desired gene into the cell and integrate it into the genome, providing long-term regulation of targeted genes. Silencing overexpressed genes promote the tumor cells to lose invasiveness, prevents their proliferation, and triggers their apoptosis. The uniqueness of cancer cells among patients requires novel therapeutic methods that treat patients based on their unique mutations. Several studies showed the effectiveness of different approaches such as microRNA, drug- or chemotherapy-related methods in treating the disease; however, identifying various targets was challenging to understanding disease progression. In this regard, the patient-specific abnormal gene might be targeted using genomics and molecular advancements such as RNA interference approaches. Here, we review potential therapeutic targets for the RNA interference approach, which is applicable as a therapeutic option for osteosarcoma patients, and we point out how the small interfering RNA method becomes a promising approach for the unmet challenge.

FBXW7 circular RNA regulates proliferation, migration and invasion of colorectal carcinoma through NEK2, mTOR, and PTEN signaling pathways in vitro and in vivo

BackgroundsA number of circular RNAs (circRNAs) have been identified in various cancer including F-box and WD repeat domain containing 7 (FBXW7) circular RNA (circ-FBXW7), which can suppress glioma cell growth. However, the role of circ-FBXW7 in colorectal cancer (CRC) remains unclear. We aimed to investigate the effect and mechanisms of circ-FBXW7 on CRC progression.MethodsThe expression of circ-FBXW7 in CRC patients was detected by PCR. Stably knockdown of circ-FBXW7 (si circ-FBXW7) cell lines and overexpression of circ-FBXW7 (oe circ-FBXW7) cell lines were constructed by small interfering RNA method and plasmids transfection in CRC SW480 and SW620 cells. The functional experiments including cell proliferation, migration and invasion were carried out by cell counting kit-8 (CCK-8) assay, wound healing assay and trans well assay. The xenograft animal models were established to evaluate the effect and the underlying molecular mechanisms of circ-FBXW7 on CRC progression.ResultsCRC samples had a significantly lower level of circ-FBXW7 compared to normal tissue. si circ-FBXW7 notably promoted the proliferation, colony formation, cell migration and invasion of CRC cell in vitro. On contrast, circ-FBXW7 overexpressed significantly suppressed CRC cell proliferation, migration and invasion. Similarly, si circ-FBXW7 stimulated the tumor growth and circ-FBXW7 overexpression repressed the tumor progression in SW480 and SW620 tumor models, which suggested that circ-FBXW7 could serve as a target biomarker of CRC. Further study found that si circ-FBXW7 up-regulated the mRNA and protein expressions of NEK2 and mTOR, and diminished the PTEN expression. Whereas, overexpressed circ-FBXW7 induced the tumor suppression via reversing the expressions of NEK2, mTOR, and PTEN.Conclusioncirc-FBXW7 plays a major role in controlling the progression of CRC through NEK2, mTOR, and PTEN signaling pathways and may be a potential therapeutic target for CRC treatment.Graphical abstractCirc-FBXW7 controls the progression of CRC through NEK2, mTOR, and PTEN signaling pathways and its overexpression inhibits colorectal cancer cell migration and invasion, suggesting the potential therapeutic target for CRC treatment.

A Differential Hypofunctionality of G\u03b1i Proteins Occurs in Adolescent Idiopathic Scoliosis and Correlates with the Risk of Disease Progression

Adolescent idiopathic scoliosis is the most prevalent spine deformity and the molecular mechanisms underlying its pathophysiology remain poorly understood. We have previously found a differential impairment of melatonin receptor signaling in AIS osteoblasts allowing the classification of patients into three biological endophenotypes or functional groups (FG1, FG2 and FG3). Here, we provide evidence that the defect characterizing each endophenotype lies at the level of Gαi proteins leading to a systemic and generalized differential impairment of Gi-coupled receptor signaling. The three Gαi isoforms exhibited a selective serine phosphorylation patterns for each AIS endophenotype resulting in a differential reduction in Gαi protein activity as determined by cellular dielectric spectroscopy and small interfering RNA methods. We found that one endophenotype (FG2) with phosphorylated Gαi1 and Gαi2 was consistently associated with a significantly high risk of spinal deformity progression when compared to the other two endophenotypes (FG1 and FG3). We further demonstrated that each endophenotype is conserved among affected family members. This study expands our understanding of the mechanism underlying the Gi-coupled receptor signaling dysfunction occurring in AIS and provides the first evidence for its hereditary nature. Collectively, our findings offers a new perspective on Gαi hypofunctionality in a human disease by revealing specific serine phosphorylation signatures of Gαi isoforms that may facilitate the identification of AIS patients at risk of spinal deformity progression.

Down-regulation of vascular GLP-1 receptor expression in human subjects with obesity

It has been thought that incretin signaling prevents arteriosclerosis, and very recently anti-arteriosclerotic effects through GLP-1 receptor were finally demonstrated in clinical human study. The purpose of this study was to investigate how vascular GLP-1 receptor expression is influenced in human subjects. First, we evaluated GLP-1 receptor expression in human arteries in immunostaining. Next, we separated the artery into the intima and media, and evaluated gene expression levels of various factors. We divided the subjects into obesity and non-obesity group and compared their expression levels between them. Finally, we evaluated which factors determine vascular GLP-1 receptor expression. GLP-1 receptor expression in intima and media was lower in obesity group compared to non-obesity group which was correlated with the alteration of TCF7L2 expression. Multiple regression analyses showed that BMI was an independent determining factor for GLP-1 receptor expression in the intima and media. Furthermore, using small interfering RNA method and TCF7L2-EGFP adenovirus, we showed that TCF7L2 was involved in GLP-1 receptor expression in human vascular cells. Taken together, vascular GLP-1 receptor and TCF7L2 expression was significantly down-regulated in human subjects with obesity. In addition, it is likely that TCF7L2 functions as a modulator of vascular GLP-1 receptor expression.

Naringenin reduces oxidative stress and improves mitochondrial dysfunction via activation of the Nrf2/ARE signaling pathway in neurons.

Oxidative stress and mitochondrial dysfunction are considered to be major contributing factors in the development and progression of many neurodegenerative diseases. Naringenin (NAR) is an abundant flavanone in the Citrus genus and has been found to exert antioxidant, anticarcinogenic and antimutagenic effects. However, the potential underlying mechanism of its antioxidant effects remains unclear. In the present study, the authors investigated the antioxidant effect of NAR on neurons invitro. Neurons isolated from the brains of Sprague-Dawley rats were randomly divided into a control group, model group, NAR-L group, NAR-M group and NAR-H group. The model group received hypoxia and re-oxygenation treatment, and the NAR-L, NAR-M and NAR-H groups received 20, 40 and 80µM NAR, respectively. The levels of reactive oxygen species (ROS) in each group were detected by chloromethyl-2',7'dichlorodihydro fluorescein diacetate staining, and differences in mitochondrial dysfunction were analyzed through measurement of mitochondrial membrane potential (∆ψm), adenine nucleotide translocase transport activity and adenine nucleotide levels. MTT and flow cytometry assays were also used to analyze cell proliferation and apoptosis, and the effects of NAR on the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) signaling pathway were investigated using small interfering RNA methods. The authors detected an increased accumulation of ROS in the model group, and high-dose NAR could significantly reduce the levels of ROS. Furthermore, NAR could improve mitochondrial dysfunction, as indicated by increased levels of high-energy phosphates, enhanced mitochondrial ANT transport activity and increased mitochondrial membrane potential. Moreover, NAR increased cell viability and decreased the rate of cell apoptosis. NAR also increased the expression of Nrf2 and its downstream target genes. These findings demonstrated that NAR could reduce oxidative stress and improve mitochondrial dysfunction via activation of the Nrf2/ARE signaling pathway in neurons.

Clinical significance and therapeutic potential of prostate cancer antigen-1/ALKBH3 in human renal cell carcinoma.

Prostate cancer antigen-1 (PCA-1)/ALKBH3 has been recently identified in human prostate cancer and its expression is correlated with disease progression and prognosis. However, the precise role and function of PCA-1/ALKBH3 in human malignancies are largely unknown. In the present study, we investigated the clinical significance and therapeutic potential of PCA-1/ALKBH3 in renal cell carcinoma (RCC). PCA-1/ALKBH3 expression was examined by immunohistochemistry in 101 RCC patients who underwent radical or partial nephrectomy. Its expression was positively correlated with advanced pathological T- and M-factors and TNM stage (T, P<0.05; M, P<0.01; TNM, P<0.01, respectively). In the prognostic analysis, PCA-1/ALKBH3-negative patients with RCC had a significantly better prognosis than PCA-1/ALKBH3-positive patients (5-year survival rate, 92.9 vs. 75.9%, respectively; P<0.05). Next, the therapeutic potential of targeting PCA-1/ALKBH3 was further evaluated by small interfering RNA method using a human RCC cell line (CAKI-1). We found that PCA-1/ALKBH3 knockdown significantly inhibited the growth of CAKI-1 cells compared with the control (P<0.001). Furthermore, knockdown of PCA-1 induced apoptosis in CAKI-1 cells, as assessed by poly(ADP-ribose) polymerase-cleavage assays. We demonstrated for the first time that PCA-1/ALKBH3 expression has a significant prognostic impact on patient prognosis in RCC. Furthermore, its knockdown has a therapeutic efficacy on RCC. Taken together, both our clinical and experimental data strongly suggest that PCA-1/ALKBH3 may be functionally important and a novel molecular target for human RCC.

Importance of C/EBPβ Binding and Histone Acetylation Status in the Promoter Regions for Induction of IGFBP-1, PRL, and Mn-SOD by cAMP in Human Endometrial Stromal Cells

Dynamic changes of gene expressions occur in human endometrial stromal cells (ESCs) during decidualization. CCAAT/enhancer-binding proteinβ (C/EBPβ) regulates the expression of a number of decidualization-related genes. In addition to transcription factors, it is important to know the role of epigenetic mechanisms, such as histone modifications in the regulation of decidualization-related genes. This study investigated the molecular and epigenetic mechanisms by which cAMP up-regulates the expression of IGF-binding protein-1 (IGFBP-1), prolactin (PRL), and manganese superoxide dismutase (Mn-SOD) in ESC. ESCs isolated from proliferative phase endometrium were incubated with cAMP to induce decidualization. IGFBP-1, PRL, and Mn-SOD mRNA expressions were determined by real-time RT-PCR. The C/EBPβ binding and histone modification status (acetylation of histone-H3 lysine-27 [H3K27ac]) in the promoter were examined by chromatin immunoprecipitation assay. Knockdowns of C/EBPβ were performed using the small interfering RNA method. cAMP induced mRNA expressions of IGFBP-1 and PRL accompanied by the increases in both C/EBPβ binding activities and H3K27ac levels in the promoters. The stimulatory effects of cAMP on mRNA levels and H3K27ac levels were completely abolished by C/EBPβ knockdown. cAMP increased Mn-SOD mRNA levels and C/EBPβ binding activities in the enhancer region. C/EBPβ knockdown inhibited Mn-SOD mRNA levels. The H3K27ac levels in the enhancer were high before cAMP stimulus but were not further increased by cAMP and were not inhibited by C/EBPβ knockdown. These results show that C/EBPβ regulates the expression of IGFBP-1 and PRL by altering the histone acetylation status of their promoters but differently regulates Mn-SOD gene expression in human ESC during decidualization.

IL-4 confers resistance to IL-27–mediated suppression on CD4+ T cells by impairing signal transducer and activator of transcription 1 signaling

TH2 cells play a critical role in the pathogenesis of allergic asthma. Established TH2 cells have been shown to resist reprogramming into TH1 cells. The inherent stability of TH2 cells poses a significant barrier to treating allergic diseases. We sought to understand the mechanisms by which CD4(+) T cells from asthmatic patients resist the IL-27-mediated inhibition. We isolated and cultured CD4(+) T cells from both healthy subjects and allergic asthmatic patients to test whether IL-27 can inhibit IL-4 production by the cultured CD4(+) T cells using ELISA. Culturing conditions that resulted in resistance to IL-27 were determined by using both murine and human CD4(+) T-cell culture systems. Signal transducer and activator of transcription (STAT) 1 phosphorylation was analyzed by means of Western blotting and flow cytometry. Suppressor of cytokine signaling (Socs) mRNA expression was measured by using quantitative PCR. The small interfering RNA method was used to knockdown the expression of Socs3 mRNA. We demonstrated that CD4(+) T cells from asthmatic patients resisted the suppression of IL-4 production mediated by IL-27. We observed that repeated exposure to TH2-inducing conditions rendered healthy human CD4(+) T cells resistant to IL-27-mediated inhibition. Using an invitro murine culture system, we further demonstrated that repeated or higher doses of IL-4 stimulation, but not IL-2 stimulation, upregulated Socs3 mRNA expression and impaired IL-27-induced STAT1 phosphorylation. The knockdown of Socs3 mRNA expression restored IL-27-induced STAT1 phosphorylation and IL-27-mediated inhibition of IL-4 production. Our findings demonstrate that differentiated TH2 cells can resist IL-27-induced reprogramming toward TH1 cells by downregulating STAT1 phosphorylation and likely explain why the CD4(+) T cells of asthmatic patients are resistant to IL-27-mediated inhibition.

Metformin inhibits P‐glycoprotein expression via the NF‐κB pathway and CRE transcriptional activity through AMPK activation

The expression of P-glycoprotein (P-gp), encoded by the multidrug resistance 1 (MDR1) gene, is associated with the emergence of the MDR phenotype in cancer cells. We investigated whether metformin (1,1-dimethylbiguanide hydrochloride) down-regulates MDR1 expression in MCF-7/adriamycin (MCF-7/adr) cells. MCF-7 and MCF-7/adr cells were incubated with metformin and changes in P-gp expression were determined at the mRNA, protein and functional level. Transient transfection assays were performed to assess its gene promoter activities, and immunoblot analysis to study its molecular mechanisms of action. Metformin significantly inhibited MDR1 expression by blocking MDR1 gene transcription. Metformin also significantly increased the intracellular accumulation of the fluorescent P-gp substrate rhodamine-123. Nuclear factor-κB (NF-κB) activity and the level of IκB degradation were reduced by metformin treatment. Moreover, transduction of MCF-7/adr cells with the p65 subunit of NF-κB induced MDR1 promoter activity and expression, and this effect was attenuated by metformin. The suppression of MDR1 promoter activity and protein expression was mediated through metformin-induced activation of AMP-activated protein kinase (AMPK). Small interfering RNA methods confirmed that reduction of AMPK levels attenuates the inhibition of MDR1 activation associated with metformin exposure. Furthermore, the inhibitory effects of metformin on MDR1 expression and cAMP-responsive element binding protein (CREB) phosphorylation were reversed by overexpression of a dominant-negative mutant of AMPK. These results suggest that metformin activates AMPK and suppresses MDR1 expression in MCF-7/adr cells by inhibiting the activation of NF-κB and CREB. This study reveals a novel function of metformin as an anticancer agent.

Clinical Significance of Prostate Stem Cell Antigen Expression in Non-small Cell Lung Cancer

Prostate stem cell antigen was originally identified as an overexpressed gene in prostate cancer and its overexpression correlated with disease progression and prognosis. In this study, we investigated the clinical significance and therapeutic potential of prostate stem cell antigen expression in non-small cell lung cancer. Prostate stem cell antigen expression was examined by immunohistochemistry in 97 primary tumors and 21 metastatic lymph nodes from non-small cell lung cancer patients who underwent curative resection from January 2001 through March 2003. Therapeutic potential of targeting prostate stem cell antigen was further examined by small interfering RNA method using human lung cancer cell line (A549). Prostate stem cell antigen protein expression was detected in 94 of 97 primary lesions (97%) and all metastatic lymph nodes. Prostate stem cell antigen expression intensity was positively correlated with advanced pathological T-factor and stage (T1 vs. T2-4, P = 0.014; Stage I vs. Stages II-IV, P = 0.029, respectively). The prognosis of patients with low prostate stem cell antigen expression was significantly better than those with high prostate stem cell antigen expression (5-year disease-free survival rate; 90% vs. 53%, P = 0.001). Finally, small interfering RNA-mediated knockdown of prostate stem cell antigen resulted in the inhibition of lung cancer cell growth. Prostate stem cell antigen is highly expressed in non-small cell lung cancer and may be functionally important for this fatal disease.

Gp78 Cooperates with RMA1 in Endoplasmic Reticulum-associated Degradation of CFTRΔF508

Misfolded or improperly assembled proteins in the endoplasmic reticulum (ER) are exported into the cytosol and degraded via the ubiquitin-proteasome pathway, a process termed ER-associated degradation (ERAD). Saccharomyces cerevisiae Hrd1p/Der3p is an ER membrane-spanning ubiquitin ligase that participates in ERAD of the cystic fibrosis transmembrane conductance regulator (CFTR) when CFTR is exogenously expressed in yeast cells. Two mammalian orthologues of yeast Hrd1p/Der3p, gp78 and HRD1, have been reported. Here, we demonstrate that gp78, but not HRD1, participates in ERAD of the CFTR mutant CFTRDeltaF508, by specifically promoting ubiquitylation of CFTRDeltaF508. Domain swapping experiments and deletion analysis revealed that gp78 binds to CFTRDeltaF508 through its ubiquitin binding region, the so-called coupling of ubiquitin to ER degradation (CUE) domain. Gp78 polyubiquitylated in vitro an N-terminal ubiquitin-glutathione-S-transferase (GST)-fusion protein, but not GST alone. This suggests that gp78 recognizes the ubiquitin that is already conjugated to CFTRDeltaF508 and catalyzes further polyubiquitylation of CFTRDeltaF508 in a manner similar to that of a multiubiquitin chain assembly factor (E4). Furthermore, we revealed by small interfering RNA methods that the ubiquitin ligase RMA1 functioned as an E3 enzyme upstream of gp78. Our data demonstrates that gp78 cooperates with RMA1 with E4-like activity in the ERAD of CFTRDeltaF508.

1. Neuroscience Series Investigation of Signaling Pathways in Cultured Pituitary Adenoma Cell by Full-length Clone Transfection and Gene Silencing with the Small Interfering RNA Method(5)

1. Neuroscience Series Investigation of Signaling Pathways in Cultured Pituitary Adenoma Cell by Full-length Clone Transfection and Gene Silencing with the Small Interfering RNA Method(5)

A novel gene, RSRC2, inhibits cell proliferation and affects survival in esophageal cancer patients.

In Japan and China, esophageal cancer is common and more than 90% of esophageal cancers are squamous cell carcinoma. Esophageal squamous cell carcinoma (ESCC) shows a poor prognosis, but the mechanism of ESCC and target genes for treatment remains unclear. We searched for genes related to ESCC, and identified a novel gene, FLJ11021, which was designated arginine/serine-rich coiled-coil 2 (RSRC2). We sought to determine the role of RSRC2 in the proliferation of esophageal cell lines and to examine the relationship between RSRC2 and clinicopathologic factors and ESCC prognosis. Expression of RSRC2 was quantified by real-time reverse transcription polymerase chain reaction (RT-PCR) in 70 primary ESCCs and paired noncancerous esophageal mucosa. To determine the role of RSRC2 in ESCC cell proliferation, we used vector-based transfection and small interfering RNA methods. Our results show that RSRC2mRNA levels in all ESCC cell lines (TE1-15, excluding TE7) were lower than those in a human esophageal squamous epithelial cell line (Het-1A). Cell proliferation of an ESCC cell line was inhibited by overexpression of RSRC2, while reduced expression was accompanied by tumor progression. RSRC2 expression levels were significantly correlated with depth of invasion, lymph node metastasis, lymphatic invasion and vascular invasion. Moreover, ESCC patients with low RSRC2mRNA expression had significantly shorter post-operative survival time than those with high expression. In vitro study revealed that RSRC2 might play a role in cell proliferation. Our study demonstrated that RSRC2 expression may be a novel tumor suppressor of esophageal cancer cell growth and a prognostic factor in ESCC.

Evaluation of anti-Fas ligand-induced apoptosis and neural differentiation of PC12 cells treated with nerve growth factor using small interfering RNA method and sampling by microdialysis

The small interfering RNA (siRNA) method is an effective technique for silencing gene expression and is a useful tool for screening the gene functions in drug discovery. Our study found that nerve growth factor (NGF) can increase the cell viability of PC12 cells and that NGF induction up-regulates the expression of Bcl-2 detected by real-time reverse transcription–polymerase chain reaction (RT–PCR). To further investigate the role of Bcl-2 expression in NGF-treated PC12 cells, the plasmid of Bcl-2 siRNA was then transfected into PC12 cells. Moreover, to investigate and continuously monitor the real-time dynamic neurotransmitter release, and to compare with the time course of Bcl-2 expression, a liquid chromatography coupled with electrochemical detection (LC–ED) and with a microdialysis device was used. After 6 h of NGF being added to the PC12 cell culture medium, the dopamine (DA) concentrations were significantly increased ( P < 0.05). This result is simultaneously compatible with the up-regulated messenger RNA (mRNA) expressions of tyrosine hydroxylase (TH), aromatic acid decarboxylase (AADC), and Bcl-2 by RT–PCR. Using the Bcl-2 siRNA method, our data revealed that NGF can inhibit Fas ligand (FasL)-induced apoptosis in PC12 cells through the activation of Bcl-2. The in vitro observation further demonstrated that NGF can stimulate the neurite development in PC12 cells through the activation of Bcl-2. Moreover, the DA concentrations of NGF induction were decreased specifically by Bcl-2 siRNA ( P < 0.05). In sum, our data support that NGF prevents Fas-induced apoptosis, facilitates neural differentiation, promotes dendritic formation, and increases DA release in PC12 cells through activation of Bcl-2.

P53‐mediated enhancement of radiosensitivity by selenophosphate synthetase 1 overexpression

Selenium has been associated with cancer prevention. Despite vast knowledge of selenium effect on various health conditions, functional characterization of selenium metabolic enzymes on cellular physiology has been limited. Therefore, to gain insight into the mechanisms underlying cancer prevention by selenium, we investigated sps1, one of the two human selenophosphate synthetase genes for its role in cancer cell's response to ionizing radiation. Although stable expression of Sps1 protein per se had little effect on cell proliferation, concurrent irradiation decreased viability of the sps1 cell line. The increased sensitivity of the cell lines to ionizing radiation was correlated with increased p53 activity as well as with simultaneous up- and downregulation of Bax and Bcl2, respectively. Knockdown of sps1 and p53 by small interfering RNA method revealed that the level of p53 was proportional to that of Sps1 and that the increased radiosensitivity was dependent upon p53. Sps1 cell lines displayed decreased level of reactive oxygen species (ROS) with concomitant increase of certain redox enzymes. Furthermore, p53 activity was regulated by cellular redox via Ref1 in sps1 cell lines. Collectively, our results demonstrated that sps1 was able to affect cell viability upon ionizing radiation via modulation of p53 activity. They further suggest that Sps1 and its reaction product selenophosphate might be involved in cancer prevention in a p53-dependent manner and could be applied to development of a novel cancer therapy.