shRNA Plasmid Research Articles

Liposomes co-Loaded with 6-Phosphofructo-2-Kinase/Fructose-2, 6-Biphosphatase 3 (PFKFB3) shRNA Plasmid and Docetaxel for the Treatment of non-small Cell Lung Cancer.

Non-small cell lung cancer is the leading cause of cancer related deaths globally. Considering the side effects and diminishing chemosensitivity to chemotherapy, novel treatment approaches are sought. Hence, we aim to develop a liposomal co-delivery system of pDNA expressing shRNA against PFKFB3 (pshPFKFB3) and docetaxel (DTX). Cationic DTX liposomes complexed with pshPFKFB3 (PSH-DL) were developed. In vitro cell line studies were performed to evaluate transfection, PFKFB3 mRNA silencing, cytotoxicity, pGP inhibition, and protein markers expression. In vivo efficacy study was performed in A549 xenograft nude mice model. Cytotoxicity studies showed significantly enhanced anticancer activity of PSH-DL against individual treatment alone confirming the chemoenhancing effect of pshPFKFB3 on DTX activity. Fluorescence microscopy and RT-PCR showed effective transfection and RNAi by pshPFKFB3. pGP inhibition assay and western blotting revealed that PFKFB3 downregulation caused diminution of pGP activity leading to changes in cell cycle (Cdk2), survival (survivin), apoptosis (Bcl2 and cleaved caspase 3) and stress (p-JNK and p-p38) markers so that induces apoptosis by PSH-DL in NSCLC cells. PSH-DL also showed ~3.8-fold reduction in tumor volume in A549 xenograft model which was significantly higher thanindividual treatments alone. Targeting PFKFB3 through shRNA based RNAi is a promising approach for potentiating activity of DTX in NSCLC.

LKB1 regulates epithelial-mesenchymal transition in Peutz-Jeghers hamartoma and intestinal epithelial cells

To investigate the molecular mechanism by which LKB1 regulates epithelial-mesenchymal transition (EMT) in Peutz-Jeghers hamartoma and intestinal epithelial cells. Immunohistochemistry was used to detect gene expression of LKB1, E-cadherin, and vimentin in 20 hamartoma tissues and 10 normal intestinal tissues, and collagen fiber deposition was analyzed using Masson trichrome staining. Normal intestinal epithelial NCM460 cells were transfected with LKB1 shRNA plasmid or negative control via lentiviral vectors, and the role of LKB1 in cell polarization and migration were determined using CCK8 and Transwell assays. Western blotting, quantitative real-time PCR (qPCR) and immunofluorescence were used to assess the alterations of EMT markers in the cells with LKB1 knockdown. Compared with normal intestinal tissues, hamartoma polyps showed significantly decreased LKB1 and E-cadherin expressions and increased vimentin expression with increased collagen fiber deposition. The cells with LKB1 knockdown exhibited enhanced cell proliferation and migration activities (P<0.01). Western blot analysis, qPCR and immunofluorescence all detected decreased E-cadherin and increased N-cadherin, vimentin, Snail, and Slug expressions in the cells with LKB1 knockdown. s LKB1 deficiency triggers EMT in intestinal epithelial cells and Peutz-Jeghers hamartoma, suggesting that EMT can serve as the therapeutic target for treatment of Peutz-Jeghers syndrome.

Effects of silenced PAR-2 on cell proliferation, invasion and metastasis of esophageal cancer.

The present study aimed to investigate the effect of protease-activated receptor 2 (PAR-2) on cell proliferation, invasion and metastasis in the esophageal EC109 cell line. Two short hairpin RNA (shRNA) expression plasmids were constructed based on the PAR-2 mRNA sequence in humans, and they were transfected into the EC109 esophageal cancer cell line, and the stable interference cell line (shRNA-PAR-2 EC109) was obtained by puromycin selection. Following transfection of PAR-2 shRNA-1, PAR-2 expression was significantly downregulated in mRNA level and protein level in EC109 cells (P<0.05). The proliferation of EC109 cells transfected with PAR-2 shRNA was significantly lower than the negative control group (P<0.05). At 24, 48 and 72 h, the ratio of proliferation inhibition was 15.92, 24.89 and 32.28%, respectively. Compared with the control group, S-phase arrest was observed in cells transfected with shRNA-PAR-2. The ratio of cells in the S phase was 32.79±4.06, 26.54±1.37 and 33.45±2.46% at 24, 48 and 72 h, respectively. For invasion, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.05). For metastasis assay, the number of invasive cells was significantly lower in shRNA-PAR2-2 cells compared with the control group (P<0.01). In the present study, the PAR-2 shRNA plasmid was constructed successfully, which can significantly downregulate PAR-2 expression in EC109 cells. Subsequent to silencing of PAR-2, the proliferation of EC109 cells was inhibited and the capabilities of invasion and migration were reduced. It is indicated that PAR-2 may be a potential target in esophageal cancer.

Star-shaped amphiphilic hyperbranched polyglycerol derivatives co-deliver docetaxel and MMP-9 shRNA plasmid to tumors

Star-shaped amphiphilic hyperbranched polyglycerol derivatives co-deliver docetaxel and MMP-9 shRNA plasmid to tumors

TET2 Protects against oxLDL-Induced HUVEC Dysfunction by Upregulating the CSE/H2S System.

Ten-eleven translocation-2 (TET2) protein is a DNA demethylase that regulates gene expression through DNA demethylation and also plays important roles in various diseases including atherosclerosis. Endothelial dysfunction represents an early key event in atherosclerotic disease. The cystathionine-γ-lyase (CSE)/hydrogen sulfide (H2S) is a key endogenous system with protective effects on endothelial functions. In this study, we examined how TET2 regulates oxidized low-density lipoprotein (oxLDL)-induced dysfunction of human umbilical vein endothelial cells (HUVECs) and determined the role of the CSE/H2S system. Treatment with oxLDL resulted in downregulation of both TET2 expression and CSE/H2S system in HUVECs. TET2 was found to have protective effects on oxLDL-induced HUVEC dysfunction, which was confirmed with TET2 overexpression plasmid or TET2 shRNA plasmid. Moreover, TET2 was found to upregulate the CSE/H2S system and inhibit NF-κB activation, leading to decreased expression of ICAM-1 and VCAM-1 and attenuated adhesion of THP-1 cells to oxLDL-activated HUVECs. The protective effect of TET2 was reduced by treatment with CSE siRNA. Further studies revealed that CSE promoter region contains a well-defined CpG island. We also showed that TET2 enhanced 5-hydroxymethylcytosine (5hmC) level and promoted DNA demethylation of CSE gene promoter, leading to an increase in CSE expression. In conclusion, TET2 has protective effects on oxLDL-induced HUVEC dysfunction, likely through upregulating the CSE/H2S system by DNA demethylation of CSE gene promoter. TET2 may become a novel therapeutic target for endothelial dysfunction-associated vascular diseases.

Differences in Zbtb7a expression cause heterogeneous changes in human nasopharyngeal carcinoma CNE3 sublines

The present study aimed to determine the association between changes in Zbtb7a expression levels and heterogeneity of nasopharyngeal carcinoma (NPC) CNE3 sublines. CNE3 sublines were established by screening of serial dilution and continuous passage. Proliferative ability and tumorigenicity of the sublines were analyzed separately by soft-agar colony formation and mouse studies. The NPC tissues from mice were analyzed by histological evaluation and immunohistochemistry. The expression levels of Zbtb7a mRNA and protein were analyzed separately by quantitative reverse transcription polymerase chain reaction and western blotting. According to findings from the soft-agar colony formation and mouse studies, two sublines with increased tumorigenicity compared with other sublines were transfected transiently with Zbtb7a short hairpin RNA (shRNA) recombinant plasmid. The changes in viability, migration and invasion abilities were evaluated separately by MTT, colorimetric focus-formation, Transwell migration and invasion assays. The sublines CNE3-GX6 and CNE3-GX11 were selected for subsequent study due to increased tumorigenicity and increased Zbtb7a expression levels compared with the other sublines. High metastatic potency was not observed in all of the sublines. Zbtb7a expression levels were positively associated with tumorigenic degree of the sublines. The growth, migration and invasion abilities of the sublines transfected with Zbtb7a shRNA plasmid were decreased compared with the cells transfected with empty vector in the negative control group. The findings suggest Zbtb7a expression levels may be associated with heterogeneity of CNE3 sublines. Therefore, Zbtb7a may have an important role in the regulatory mechanism of NPC heterogeneity.

Abstract 1534: The significance of a p53 gain-of-function mutation in the acquisition of metastatic traits in the SW13 cell line

Abstract The therapeutic potential of histone deacetylase inhibitors (HDACi), shown to epigenetically regulate a variety of genes, has yet to be fully realized due to their documented pleiotropic effects in vivo. Currently, four HDACi are FDA-approved for the treatment of hematological malignancies, but their effectiveness against other types of cancers have been shown to be limited at best and, as a result, most of these clinical trials have failed. A comprehensive review of the recent literature has identified that approximately 50% of all cell lines treated with an HDACi demonstrate an increase in metastatic potential as measured by increases in migration and invasion. Of these cell lines that respond with increased metastatic potential to HDACi treatment, 60% have a gain-of-function mutation within p53 (p=0.03). As HDACi have been shown to destabilize mutant p53, they have been used in studies to examine the effects of HDACi treatment on cancers with an identified p53 mutation. This is concerning as the specific p53 mutation in these cancers is not always known, and thus treatment could potentially result in an increase in cancer cell growth. Previous work in our lab demonstrates that the human SW13 adrenal adenocarcinoma cell line, which harbors a homozygous H193Y gain-of-function mutation, does have an HDACi-induced metastatic phenotype; treated cells demonstrate significant increases in MMP activity and ~50% reduction in p53 protein expression compared to untreated cells. To investigate the role that a decrease in mutant p53 expression plays in the acquisition of metastatic characteristics we utilized stable shRNA plasmids to knock-down p53 expression in the SW13 cell line. HeLa cells, which possess a wild-type p53 gene, were used as a positive control. We found that a decrease in p53 expression alone was not sufficient to induce changes in SW13 growth or invasiveness. In fact, even though p53 expression was knocked down by ~70% in the shRNA lines, HDAC inhibition still induced the acquisition of metastatic properties in these cells. Intriguingly, while the DNA binding activity of mutant p53 was correlated with protein expression and was significantly decreased following HDAC inhibition, the same response was not observed in HeLa cells. These findings suggest that p53 status may be an important determinant of therapeutic response to HDAC inhibition. Note: This abstract was not presented at the meeting. Citation Format: McKale Montgomery, Elizabeth Hull. The significance of a p53 gain-of-function mutation in the acquisition of metastatic traits in the SW13 cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1534. doi:10.1158/1538-7445.AM2017-1534

PHLDA1 (pleckstrin homology-like domain, family A, member 1) knockdown promotes migration and invasion of MCF10A breast epithelial cells

ABSTRACTPHLDA1 (pleckstrin homology-like domain, family A, member 1) is a multifunctional protein that plays distinct roles in several biological processes including cell death and therefore its altered expression has been identified in different types of cancer. Progressively loss of PHLDA1 was found in primary and metastatic melanoma while its overexpression was reported in intestinal and pancreatic tumors. Previous work from our group showed that negative expression of PHLDA1 protein was a strong predictor of poor prognosis for breast cancer disease. However, the function of PHLDA1 in mammary epithelial cells and the tumorigenic process of the breast is unclear. To dissect PHLDA1 role in human breast epithelial cells, we generated a clone of MCF10A cells with stable knockdown of PHLDA1 and performed functional studies. To achieve reduced PHLDA1 expression we used shRNA plasmid transfection and then changes in cell morphology and biological behavior were assessed. We found that PHLDA1 downregulation induced marked morphological alterations in MCF10A cells, such as changes in cell-to-cell adhesion pattern and cytoskeleton reorganization. Regarding cell behavior, MCF10A cells with reduced expression of PHLDA1 showed higher proliferative rate and migration ability in comparison with control cells. We also found that MCF10A cells with PHLDA1 knockdown acquired invasive properties, as evaluated by transwell Matrigel invasion assay and showed enhanced colony-forming ability and irregular growth in low attachment condition. Altogether, our results indicate that PHLDA1 downregulation in MCF10A cells leads to morphological changes and a more aggressive behavior.

A short hairpin RNA-based adjuvant targeting NF-κB repressor IκBα promotes migration of dermal dendritic cells to draining lymph nodes and antitumor CTL responses induced by DNA vaccination

DNA vaccination is an attractive approach to elicit tumor-specific cytotoxic CD8+ T lymphocytes (CTL), which can mediate protective immunity against tumors. To initiate CTL responses, antigen-encoding plasmids employed for DNA vaccination need to activate dendritic cells (DC) through the stimulation of DNA-sensing innate immune receptors that converge in the activation of the master transcription factor NF-κB. To this end, NF-κB repressor IκBα needs to be degraded, allowing NF-κB to translocate to the nucleus and transcribe proinflammatory target genes, as well as its repressor IκBα. Therefore, NF-κB activation is self-limited by de novo synthesis of IκBa, which sequesters NF-κB in the cytosol. Hence, we tested whether co-delivering a shRNA-based adjuvant able to silence IκBα expression would further promote DNA-induced NFκB activation, DC activation and tumor-protective CTL responses induced by DNA vaccination in a preclinical model. First, an IκBα-targeting shRNA plasmid (shIκBα) was shown to reduce IκBα expression and promote NFκB-driven transcription in vitro, as well as up-regulate inflammatory target genes in vivo. Then, we showed that intradermal DNA electroporation induced the migration of skin migratory dendritic cells to draining lymph nodes and maturation of dermal dendritic cells (dDC). Interestingly, shIκBα further promoted the migration of mature skin migratory dendritic cells, in particular dDC, which are specialized in antigen cross-presentation and activation of CD8+ T cells. Consistently, mice vaccinated with a plasmid encoding the melanoma-associated antigen tyrosinase-related protein 2 (TRP2) in combination with shIκBα enhanced TRP2-specific CTL responses and reduced the number of lung melanoma foci in mice challenged with intravenous injection of B16F10 cells. Moreover, therapeutic vaccination with pTRP2 and shIκBα delayed the growth of B16F10 melanoma subcutaneous tumors. Our data suggest that adjuvants promoting NF-κB activation represent an attractive strategy to boost DC activation and promote the generation of tumor-protective CTL responses elicited by DNA vaccines.

Irreversible electroporation-mediated shRNA knockdown of the HPV18 E6 gene suppresses cervical cancer growth in vitro and in vivo.

Irreversible electroporation (IRE) is a physical, non-thermal cancer therapy, which leads to cell death via permanent membrane permeability. This differs from reversible electroporation (RE), which is used to transfer macromolecules into target cells via transient membrane permeability. Given the electrical impedance of the electric field, RE co-exists outside the central zone of IRE ablation. In the present study, the feasibility of using IRE at a therapeutic dose to mediate short hairpin RNA (shRNA) knockdown of human papillomavirus (HPV)18 E6 in HeLa cervical cancer cells in vitro and in vivo was investigated. Experimental results indicated that the HeLa cells survived the combined treatment with IRE and shRNA plasmid transfection. Additionally, residual tumor tissue in a nude mouse model demonstrated green fluorescence. Subsequent studies showed that the combined treatment inhibited the growth of HeLa cells and tumors. Western blotting analysis showed marked changes in the growth-associated proteins between the combined treatment group and the control. It was concluded that a therapeutic dose of IRE was able to mediate the transfection of HPV18 E6 shRNA into HeLa cervical cancer cells in vitro and in vivo. This combined treatment strategy has promising implications in cancer treatment for the ablation of tumors, and in eliminating microscopic residual tumor tissue.

JAK2 variations and functions in lung adenocarcinoma.

Lung cancer ranks as the first most common cancer and the first leading cause of cancer-related death in China and worldwide. Due to the difficulty in early diagnosis and the onset of cancer metastasis, the 5-year survival rate of lung cancer remains low. JAK2 has emerged as pivotal participant in biological processes, often dysregulated in a range of cancers. Recently our study found that JAK2 might play an important role in lung cancer pathogenesis. While our understanding of JAK2 in the onset and progression of lung cancer is still in its infancy, there is no doubt that understanding the variations and functions of JAK2 will certainly secure strong biomarkers and improve treatment options for lung cancer patients. The expression level of JAK2 mRNA was assayed using RT-PCR. JAK2 mutations and amplification were detected using next-generation sequencing (NGS). The shRNA and overexpression plasmids of JAK2 were conducted. MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazoliumbromide) assay, Trans-well migration and Matrigel invasion assay were conducted to study the proliferation, migration and invasion abilities of lung adenocarcinoma cells independently. We found that JAK2 mRNA was up-regulated in lung adenocarcinoma tissues when compared with their adjacent non-tumor tissues, and was associated with lymph node metastasis ( p < 0.05). JAK2 V617F and N30S mutations and JAK2 amplification were detected by NGS in plasmid samples in patients with lung adenocarcinoma. Downregulation of JAK2 inhibited the proliferation, migration and invasion abilities of lung adenocarcinoma A549 cells. Moreover, overexpression of JAK2 induced the proliferation, migration and invasion abilities of A549 cells. Thus, the up-regulation, mutation and amplification of JAK2 detected in lung adenocarcinoma may participate in lung cancer progression by regulating cancer cells' proliferation, migration and invasion.

JAK2 variations and functions in lung adenocarcinoma.

e23181 Background: Lung cancer ranks as the first most common cancer and the first leading cause of cancer-related death in China and worldwide. Due to the difficulty in early diagnosis and the onset of cancer metastasis, the 5-year survival rate of lung cancer remains extremely low. JAK2 has emerged as pivotal participant in biological processes, often dysregulated in a range of cancers, including lung cancer. Recently we found that JAK2 might play an important role in lung cancer pathogenesis as an oncogene. While our understanding of JAK2 in the onset and progression of lung cancer is still in its infancy, there is no doubt that understanding the activities of JAK2 will certainly secure strong biomarkers and improve treatment options for lung cancer patients. Methods: The expression level of JAK2 mRNA was assayed using RT-PCR. JAK2 mutations and amplification were detected using next-generation sequencing (NGS). MTT assay, Transwell migration and invasion assay were conducted to study the proliferation, migration and invasion abilities of lung adenocarcinoma cells independently. The shRNA and overexpression plasmids of JAK2 were conducted. Results: JAK2 is up-regulated in lung adenocarcinoma tissues when compared with their adjacent non-tumor tissues, and was associated with lymph node metastasis ( p&lt; 0.05). JAK2 V617F and N30S mutations and JAK2 amplification were detected by NGS in lung adenocarcinoma patient samples. Downregulation of JAK2 inhibits the proliferation, migration and invasion abilities of lung cancer cells. Moreover, overexpression of JAK2 induced the proliferation, migration and invasion abilities of lung cancer cells. Conclusions: These findings demonstrate that JAK2, whose expression is up-regulated in lung adenocarcinoma, whose mutation and amplification were detected in lung adenocarcinoma, may participate in lung cancer progression by regulating cancer cells proliferation, migration and invasion.

Tafazzin (TAZ) promotes the tumorigenicity of cervical cancer cells and inhibits apoptosis.

Tafazzin (TAZ) is often aberrantly expressed in some cancers, including rectal cancer and thyroid neoplasms. However, the function of TAZ in cervical cancer cells remains unknown. This study aims to explore the expression and function of TAZ in cervical cancer cells. Here, we determined the expression of TAZ protein in normal cervical tissue (NC, n = 27), high-grade squamous intraepithelial lesions (HSIL, n = 26) and squamous cervical carcinoma (SCC, n = 41) by immunohistochemistry, the expression of TAZ protein gradually increased from NC to HSIL to SCC. TAZ was overexpressed or down-regulated in cervical cancer cells by stably transfecting a TAZ-expressing plasmid or a shRNA plasmid targeting TAZ. In vitro, the cell growth curves and MTT assays showed that TAZ may promote the growth and viability of cervical cancer cells. In vivo, xenografts experiment showed that TAZ may increase tumor-forming ability. The percentage of apoptosis cells analyzed by FACS and TUNEL assays consistently showed that TAZ inhibits apoptosis in cervical cancer cells. Furthermore, the Cleaved Caspase 9 and Cleaved Caspase 3 were down-regulated by TAZ in cervical cancer cells. Taken together, this study demonstrated that TAZ is overexpressed in cervical cancer and may promote tumorigenicity of cervical cancer cells and inhibit apoptosis.

HIF-1\u03b1 promoted vasculogenic mimicry formation in hepatocellular carcinoma through LOXL2 up-regulation in hypoxic tumor microenvironment

BackgroundThe incidence and mortality rates of hepatocellular carcinoma (HCC) have steadily increased in recent years. A hypoxic microenvironment is one of the most important characteristics of solid tumors which has been shown to promote tumor metastasis, epithelial-mesenchymal transition and angiogenesis. Epithelial-mesenchymal transition and vasculogenic mimicry have been regarded as crucial contributing factors to cancer progression. HIF-1α functions as a master transcriptional regulator in the adaptive response to hypoxia. Lysyl oxidases like 2 (LOXL2) is a member of the lysyl oxidase family, which main function is to catalyze the covalent cross-linkages of collagen and elastin in the extracellular matrix. Recent work has demonstrated that HIF-1α promotes the expression of LOXL2, which is believed to amplify tumor aggressiveness. LOXL2 has shown to promote metastasis and is correlated with poor prognosis in hepatocellular carcinoma. The purpose of our study is to explore the role of HIF-1α in progression and metastasis of hepatocellular carcinoma by promoting the expression of LOXL2 as well as the potential regulatory mechanism.MethodsHIF-1α, LOXL2 expression and CD31/periodic acid-Schiff double staining in HCC patient samples were examined by immunohistochemical staining. shRNA plasmids against HIF-1α was used to determine whether LOXL2 been increased by HIF-1α. We monitored a series of rescue assays to demonstrate our hypothesis that LOXL2 is required and sufficient for HIF-1α induced EMT and VM formation, which mediates cellular transformation and takes effect in cellular invasion. Then we performed GeneChip® Human Transcriptome Array (HTA) 2.0 in HepG2 cells, HepG2 cells overexpressed LOXL2 and HepG2 cells treated with CoCl2.ResultsIn clinical HCC tissues, it confirmed a positive relationship between HIF-1α and LOXL2 protein. Importantly, HIF-1α and LOXL2 high expression and the presence of vasculogenic mimicry were correlated to poor prognosis. HIF-1α was found to induce EMT, HCC cell migration, invasion and VM formation by regulating LOXL2. The results of microarray assays were analyzed.ConclusionHIF-1α plays an important role in the development of HCC by promoting HCC metastasis, EMT and VM through up-regulating LOXL2. This study highlights the potential therapeutic value of targeting LOXL2 for suppression of HCC metastasis and progression.

MiR-302b inhibits cancer-related inflammation by targeting ERBB4, IRF2 and CXCR4 in esophageal cancer.

Cancer related inflammation (CRI) plays an important role in the development of esophageal cancer (EC), and the target gene analysis shows that miR-302b potential target genes closely correlated to CRI important signaling pathways. The present study was to evaluate the inhibition of miR-302b on CRI in EC and its mechanism. We found that the expression levels of miR-302b in EC cells were lower than that in Het-1A cells, while TE11 with the lowest expression and OE33 with the highest. Inflammatory stimuli at 48 h significantly reduced expression of miR-302b in EC cells, but had no effect in Het-1A. After up-regulation of miR-302b in TE11 and down-regulation of miR-302b in OE33, it was found that miR-302b reduced CRI key transcription factors and representative cytokines. Then, over-expressed of miR-302b significantly altered potential target genes protein expressions and there was a negative correlation between miR-302b and potential target genes protein expressions (ERBB4, IRF2 and CXCR4) in EC tissues. Then reporter gene analysis revealed that miR-302b post-transcriptionally regulated expression of target genes by specific area of 3′-UTR. Transfected by target genes shRNA plasmids together could get the same effects of miR-302b on protein expression of CRI key transcription factors. Furthermore, miR-302b was able to repress tumor growth and transcription factors protein expression in vivo. These finding suggests that miR-302b inhibits key transcription factors and cytokines by targeting ERBB4, IRF2 and CXCR4, implicating its role in the inhibition of CRI in EC.

In vivo inhibition of influenza A virus replication by RNA interference targeting the PB2 subunit via intratracheal delivery.

BackgroundInfluenza virus infection is a major threat to human health. Small interfering RNA (siRNA) is a promising approach for the prevention and treatment of viral infections. In this study, we constructed a series of DNA vector-based short hairpin RNAs (shRNAs) that target various genes of the influenza A virus using the polymerase III U6-RNA promoter to prevent influenza virus infection in vitro and in a mouse model.ResultsThree sets of DNA vector-based shRNA, two targeting genes encoding the polymerase acidic protein (PA) and one targeting polymerase basic protein 2 (PB2), efficiently inhibited the replication of influenza virus A/WSN/33(H1N1) in vitro. We also successfully prevented influenza virus A/WSN/33(H1N1) infection in a C57BL/6 mouse model by intratracheal delivery of anti-PB2 shRNA.ConclusionsOur findings suggest that the PB2-targeting shRNA plasmid showed potential for use as an RNAi-based therapeutic for influenza virus infection.

Effect of TGF-β/smad signaling pathway blocking on expression profiles of miR-335, miR-150, miR-194, miR-27a, and miR-199a of hepatic stellate cells (HSCs).

The aim of this study was to determine the effect of inhibition of TGF-β/smad signaling on the expression profiles of miR-335, miR-150, miR-194, miR-27a, miR-199a of hepatic stellate cells (HSCs). Liver fibrosis is excessive deposition of extracellular matrix proteins due to ongoing inflammation and HSC activation that occurs in most types of chronic liver diseases. Recent studies have shown the importance of microRNAs in the pathogenesis of chronic liver diseases. In this study, for inhibition of TGF-β smad-signaling pathway, expressing Smad4 shRNA plasmids were transfected into HSCs. Subsequently, using Real Time-PCR, we measured the expression levels of miR-335, miR-150, miR-194, miR-27a and miR-199a. Gene expression analysis showed that downregulation of Smad4 by vector Smad4shRNA significantly increased the expression levels of miR-335 (P<0.01) and miR-150 (P<0.001) and decreased the expression level of miR-27a (P<0.05). The results of this study suggest that blocking TGF-β smad-signaling can also differentially modulate microRNA expression in support of activation and fibrogenesis of HSCs.

Downregulation of Bmi1 in breast cancer stem cells suppresses tumor growth and proliferation.

Targeting cancer stem cells during initial treatment is important to reduce incidence of recurrent disease. Bmi1 has been associated with cancer stem cell self-renewal and aggressive disease. The purpose of this study was to determine the effects of downregulation of Bmi1 in breast cancer stem cells in order to target and eliminate the stem cell population in the tumor mass. Bmi1 was downregulated using two approaches in the mouse breast cancer stem cell line FMMC 419II—a small molecule inhibitor (PTC 209) and stable transfection with a Bmi1 shRNA plasmid. The functional effect of Bmi1 downregulation was tested in vitro and in vivo. Each approach led to decreased Bmi1 expression that correlated with an inhibition of cancer stem cell properties in vitro including cell cycle arrest and reduced mammosphere forming potential, and a decrease in tumor mass in vivo after either intra-tumoral or systemic nanoparticle-targeted delivery of anti-Bmi1. These results show that inhibiting Bmi1 expression in breast cancer stem cells could be important for the complete elimination of tumor and potentially preventing disease relapse.

Puromycin-resistant lentiviral control shRNA vector, pLKO.1 induces unexpected cellular differentiation of P19 embryonic stem cells

RNA silencing is used as a common method for investigating loss-of-function effects of genes of interest. In mammalian cells, RNA interference (RNAi) or RNA silencing can be achieved by transient siRNA (small or short interfering RNA) transfection or by stable shRNA (short hairpin RNA) systems. Various vectors are used for efficient delivery of shRNA. Lentiviral vectors offer an efficient delivery system for stable and long-term expression of the shRNA in mammalian cells. The widely used lentiviral pLKO.1 plasmid vector is very popular in RNAi studies. A large RNAi database, a TRC (the RNAi Consortium) library, was established based on the pLKO.1-TRC plasmid vector. This plasmid (also called pLKO.1-puro) has a puromycin-resistant gene for selection in mammalian cells along with designs for generating lentiviral particles as well for RNA silencing. While using the pLKO.1-puro TRC control shRNA plasmid for transfection in murine P19 embryonic stem (ES) cells, it was unexpectedly discovered that this plasmid vector induced robust endodermal differentiation. Since P19 ES cells are pluripotent and respond to external stimuli that have the potential to alter the phenotype and thus its stemness, other cell types used in RNA silencing studies do not display the obvious effect and therefore, may affect experiments in subtle ways that would go undetected. This study for the first time provides evidence that raises concern and warrants extreme caution while using the pLKO.1-puro control shRNA vector because of its unexpected non-specific effects on cellular integrity.

Contribution of guanine nucleotide exchange factor Vav2 to NLRP3 inflammasome activation in mouse podocytes during hyperhomocysteinemia

NADPH oxidase (NOX)-derived reactive oxygen species (ROS) have been demonstrated to mediate the activation of NOD-like receptor protein 3 (NLRP3) inflammasomes in podocytes in response to elevated levels of homocysteine (Hcys). However, it remains unknown how NLRP3 inflammasome activation is triggered by NOX. The present study tested whether the guanine nucleotide exchange factor Vav2 mediates Rac1-mediated NOX activation in response to elevated Hcys leading to NLRP3 inflammasome activation in podocytes and consequent glomerular injury. In a mouse model of hyperhomocysteinemia (hHcys), we found that mice with hHcys (on the FF diet) or oncoVav2 (a constitutively active form of Vav2) transfection in the kidney exhibited increased colocalization of NLRP3 with apoptosis-associated speck-like protein (ASC) or caspase-1 and elevated IL-1β levels in glomeruli, indicating the formation and activation of the NLRP3 inflammasome. This glomerular NLRP3 inflammasome activation was accompanied by podocyte dysfunction and glomerular injury, even sclerosis. Local transfection of Vav2 shRNA plasmids significantly attenuated hHcys-induced NLRP3 inflammasome activation, podocyte injury, and glomerular sclerosis. In cultured podocytes, Hcys treatment and oncoVav2 transfection were also found to increase NLRP3 inflammasome formation and activation, which were all inhibited by Vav2 shRNA. Furthermore, Vav2 shRNA prevented Hcys-induced podocyte damage as shown by restoring Hcys-impaired VEGF secretion and podocin production. This inhibitory action of Vav2 shRNA on Hcys-induced podocyte injury was associated with reduction of Rac1 activity and ROS production. These results suggest that elevated Hcys levels activate Vav2 and thereby increase NOX activity leading to ROS production, which triggers NLRP3 inflammasome activation, podocyte dysfunction and glomerular injury.