Pristimerin enhances recombinant adeno-associated virus vector-mediated transgene expression in human cell lines in vitro and murine hepatocytes in vivo

Reactive oxygen species enhance rAAV transduction by promoting its escape from late endosomes

BACKGROUND

Recent seminal studies have revealed that endosomal reactive oxygen species (ROS) promote rather than inhibit viral infection. Some ROS generators, including shikonin and H₂O₂, have the potential to enhance recombinant adeno-associated virus (rAAV) transduction. However, the impact of ROS on rAAV intracellular trafficking remains unclear.

METHODS

To understand the effects of ROS on the transduction of rAAV vectors, especially the rAAV subcellular distribution profiles, this study systematically explored the effect of ROS on each step of rAAV intracellular trafficking pathway using fluorescently-labeled rAAV and qPCR quantification determination.

RESULTS

The results showed promoted in-vivo and in-vitro rAAV transduction by ROS exposure, regardless of vector serotype or cell type. ROS treatment directed rAAV intracellular trafficking towards a more productive pathway by upregulating the expression of cathepsins B and L, accelerating the rAAV transit in late endosomes, and increasing the rAAV nucleus entry.

CONCLUSIONS

These data support that ROS generative drugs, such as shikonin, have the potential to promote rAAV vector transduction by promoting rAAV's escape from late endosomes, and enhancing its productive trafficking to the nucleus.

The use of miR122 and its target sequence in adeno-associated virus-mediated trichosanthin gene therapy

OBJECTIVE

Plant-derived cytotoxic transgene expression, such as trichosanthin (tcs), regulated by recombinant adeno-associated virus (rAAV) vector is a promising cancer gene therapy. However, the cytotoxic transgene can hamper the vector production in the rAAV producer cell line, human embryonic kidney (HEK293) cells. Here, we explored microRNA-122 (miR122) and its target sequence to limit the expression of the cytotoxic gene in the rAAV producer cells.

METHODS

A miR122 target (122T) sequence was incorporated into the 3' untranslated region of the tcs cDNA sequence. The firefly luciferase (fluc) transgene was used as an appropriate control. Cell line HEK293-mir122 was generated by the lentiviral vector-mediated genome integration of the mir122 gene in parental HEK293 cells. The effects of miR122 overexpression on cell growth, transgene expression, and rAAV production were determined.

RESULTS

The presence of 122T sequence significantly reduced transgene expression in the miR122-enriched Huh7 cell line (in vitro), fresh human hepatocytes (ex vivo), and mouse liver (in vivo). Also, the normal liver physiology was unaffected by delivery of 122T sequence by rAAV vectors. Compared with the parental cells, the miR122-overexpressing HEK293-mir122 cell line showed similar cell growth rate and expression of transgene without 122T, as well as the ability to produce liver-targeting rAAV vectors. Fascinatingly, the yield of rAAV vectors carrying the tcs-122T gene was increased by 77.7-fold in HEK293-mir122 cells. Moreover, the tcs-122T-containing rAAV vectors significantly reduced the proliferation of hepatocellular carcinoma cells without affecting the normal liver cells.

CONCLUSION

HEK293-mir122 cells along with the 122T sequence provide a potential tool to attenuate the cytotoxic transgene expression, such as tcs, during rAAV vector production.

Pristimerin Inhibits Osteoclast Differentiation and Bone Resorption in vitro and Prevents Ovariectomy-Induced Bone Loss in vivo

Introduction

Osteoporosis is a metabolic bone disease characterized by reduced bone quantity and microstructure, typically owing to increased osteoclastogenesis and/or enhanced osteoclastic bone resorption, resulting in uncontrolled bone loss, which primarily affects postmenopausal women. In consideration of the severe side effects of current drugs for osteoporosis, new safe and effective medications are necessary. Pristimerin (Pri), a quinone methide triterpene extracted from Celastraceae and Hippocrateaceae members, exhibits potent antineoplastic and anti-inflammatory effects. However, its effect on osteoclasts remains unknown.

Materials and Methods

We evaluated the anti-osteoclastogenic and anti-resorptive effect of Pri on bone marrow-derived osteoclasts and its underlying mechanism in vitro. In addition, the protective effect of Pri on ovariectomy model was also explored in vivo.

Results

In vitro, Pri inhibited osteoclast differentiation and mature osteoclastic bone resorption in a time- and dose-dependent manner. Further, Pri suppressed the expression of osteoclast-related genes and the activation of key proteins. Pri also inhibited the early activation of ERK, JNK MAPK, and AKT signaling pathways in bone marrow-derived macrophages (BMMs), ultimately inhibiting the induction and activation of the crucial osteoclast transcriptional factor nuclear factor of activated T‐cell cytoplasmic 1 (NFATc1). In vivo, consistent with our in vitro data, Pri clearly prevented ovariectomy-induced bone loss.

Conclusion

Our data showed that Pri inhibits the differentiation and activation of osteoclasts in vitro and in vivo, and could be a promising candidate for treating osteoporosis.

Mechanism for enhanced transduction of hematopoietic cells by recombinant adeno-associated virus serotype 6 vectors

Hematopoietic gene delivery, such as hematopoietic stem/progenitor cells (HSPCs), is a promising treatment for both inherited and acquired diseases, such as hemophilia. Recently, a combined strategy to achieve more than 90% transduction efficiency was documented using recombinant adeno-associated virus serotype 6 (rAAV6) vectors. However, the mechanisms of enhanced vector transduction efficiency in hematopoietic cells are largely unknown. In this manuscript, we first reported that proteasome inhibitors, which are well-known to facilitate rAAV intracellular trafficking in various cell types, are not effective in hematopoietic cells. From the screening of small molecules derived from traditional Chinese medicine, we demonstrated that shikonin, a potential reactive oxygen species (ROS) generator, significantly increased the in vitro and ex vivo transgene expression mediated by rAAV6 vectors in hematopoietic cells, including human cord blood-derived CD34 + HSPCs. Shikonin mainly targeted vector intracellular trafficking, instead of host cell entry or endonuclear single to double strand vector DNA transition, in a vector serotype-dependent manner. Moreover, a ROS scavenger completely prevented the capability of shikonin to enhance rAAV6 vector-mediated transgene expression. Taken together, these studies expand our understanding of rAAV6-mediated transduction in hematopoietic cells and are informative for improving rAAV6-based treatment of blood diseases.

Site-Directed Mutagenesis Improves the Transduction Efficiency of Capsid Library-Derived Recombinant AAV Vectors

Recombinant adeno-associated virus (rAAV) vectors selected from capsid libraries present enormous advantages in high selectivity of tissue tropism and their potential use in human gene therapy applications. For example, rAAV-LK03, was used in a gene therapy trial for hemophilia A (ClinicalTrials.gov: NCT03003533). However, high doses in patients resulted in severe adverse events and subsequent loss of factor VIII (FVIII) expression. Thus, additional strategies are needed to enhance the transduction efficiency of capsid library-derived rAAV vectors such that improved clinical efficacy can be achieved at low vector doses. In this study, we characterized two commonly used library-derived rAAV vectors, rAAV-DJ and rAAV-LK03. It was concluded that rAAV-DJ shared similar transport pathways (e.g., cell surface binding, endocytosis-dependent internalization, and cytoplasmic trafficking) with rAAV serotype 2, while rAAV-LK03 and rAAV serotype 3 shared similar transport pathways. We then performed site-directed mutagenesis of surface-exposed tyrosine (Y), serine (S), aspartic acid (D), and tryptophan (W) residues on rAAV-DJ and rAAV-LK03 capsids. Our results demonstrated that rAAV-DJ-S269T and rAAV-LK03-Y705+731F variants had significantly enhanced transduction efficiency compared to wild-type counterparts. Our studies suggest that the strategy of site-directed mutagenesis should be applicable to other non-natural AAV variants for their optimal use in human gene therapy.

Mycoplasma contamination-mediated attenuation of plasmid DNA transfection efficiency is augmented via L-arginine deprivation in HEK-293 cells

Mycoplasma infection is the most prevalent contamination in cell culture. Analysis of cell culture in laboratories from different countries shows that mycoplasma contamination ranges from 15% to 80% and, in some cases, even reaches 100% (Chernov et al., 2014). Whilst mycoplasma infection is not visible to the naked eye in cell culture, the consequences of mycoplasma contamination have been shown to induce a number of cellular changes, for example, increased resistance to chemotherapeutic drugs. Therefore, any results obtained from tissue culture studies, in the presence of mycoplasma contamination, potentially render the data invalid (Kim et al., 2015; Gedye et al., 2016). As such, mycoplasmas are not harmless bystanders and cannot be ignored in in vitro studies.

Mouse γ-Synuclein Promoter-Mediated Gene Expression and Editing in Mammalian Retinal Ganglion Cells

Optic neuropathies are a group of optic nerve (ON) diseases caused by various insults including glaucoma, inflammation, ischemia, trauma, and genetic deficits, which are characterized by retinal ganglion cell (RGC) death and ON degeneration. An increasing number of genes involved in RGC intrinsic signaling have been found to be promising neural repair targets that can potentially be modulated directly by gene therapy, if we can achieve RGC specific gene targeting. To address this challenge, we first used adeno-associated virus (AAV)-mediated gene transfer to perform a low-throughput in vivo screening in both male and female mouse eyes and identified the mouse γ-synuclein (mSncg) promoter, which specifically and potently sustained transgene expression in mouse RGCs and also works in human RGCs. We further demonstrated that gene therapy that combines AAV-mSncg promoter with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing can knock down pro-degenerative genes in RGCs and provide effective neuroprotection in optic neuropathies.SIGNIFICANCE STATEMENT Here, we present an RGC-specific promoter, mouse γ-synuclein (mSncg) promoter, and perform extensive characterization and proof-of-concept studies of mSncg promoter-mediated gene expression and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing in RGCs in vivo To our knowledge, this is the first report demonstrating in vivo neuroprotection of injured RGCs and optic nerve (ON) by AAV-mediated CRISPR/Cas9 inhibition of genes that are critical for neurodegeneration. It represents a powerful tool to achieve RGC-specific gene modulation, and also opens up a promising gene therapy strategy for optic neuropathies, the most common form of eye diseases that cause irreversible blindness.

Babao Dan induces gastric cancer cell apoptosis via regulating MAPK and NF-κB signaling pathways

Objective

The objective was to further investigate apoptosis induction by Babao Dan (BBD), which supports its anti-tumor mechanisms, using two human gastric cancer cell lines (AGS and MGC80-3).

Methods

After treatment with various BBD concentrations, cell viability and cytotoxic effects were investigated using methyl thiazolyl tetrazolium (MTT) and lactate dehydrogenase (LDH) assays, respectively. The following indicators of cell apoptosis were evaluated: Annexin V-APC staining, caspase-3/-8/-9 activation, and mitochondrial membrane potential loss. Apoptosis-related protein levels (including Bcl-2-associated X protein [Bax], B-cell CLL/lymphoma 2 [Bcl-2], factor associated suicide [Fas], and Fas ligand [FasL]) were determined by western blot. The following multi-pathway factors were also assessed: p-ERK1/2, p-JNK, p-p38, and p-NF-κB.

Results

The MTT and LDH assays both demonstrated increased BBD cytotoxicity. BBD induced cell apoptosis by stimulating caspase-3/-8/-9 activity and destroying the mitochondrial membrane potential. BBD also regulated key factor expression levels including Bcl-2, Bax, Fas, and FasL and down-regulated protein phosphorylation via the MAPK and NF-κB pathway.

Conclusions

The possible anti-tumor mechanism is that BBD induces apoptosis via the MAPK and NF-κB signaling pathways.

AKT-dependent and -independent pathways mediate PTEN deletion-induced CNS axon regeneration

Phosphatase and tensin homolog (PTEN) acts as a brake for the phosphatidylinositol 3-kinase–AKT–mTOR complex 1 (mTORC1) pathway, the deletion of which promotes potent central nervous system (CNS) axon regeneration. Previously, we demonstrated that AKT activation is sufficient to promote CNS axon regeneration to a lesser extent than PTEN deletion. It is still questionable whether AKT is entirely responsible for the regenerative effect of PTEN deletion on CNS axons. Here, we show that blocking AKT or its downstream effectors, mTORC1 and GSK3β, significantly reduces PTEN deletion-induced mouse optic nerve regeneration, indicating the necessary role of AKT-dependent signaling. However, AKT is only marginally activated in PTEN-null mice due to mTORC1-mediated feedback inhibition. That combining PTEN deletion with AKT overexpression or GSK3β deletion achieves significantly more potent axonal regeneration suggests an AKT-independent pathway for axon regeneration. Elucidating the AKT-independent pathway is required to develop effective strategies for CNS axon regeneration.

Impact of a Chinese Medicinal Formula, Xiao Liu Fang, on the "3A" Ability of Endometrial Stromal Cells in Patients with Endometriosis

The pathogenesis of endometriosis (EMS) is complicated, and treatment results are unsatisfactory. It has become the focus of gynecological research. Analysis targeting the pathogenesis of EMS is the key to providing more effective treatments. In recent years, the superiority of traditional Chinese medicine in treating EMS has been highlighted, so we investigated the impact of a Chinese medicinal formula (Xiao Liu Fang) on the “3A” ability, in situ, of ectopic endometrial stromal cells in patients with EMS. Primary endometrial stromal cells were isolated using a modified net filtration method, cultured, and identified in different groups. Endometrial cell attachment was measured using the methyl thiazolyl tetrazolium (MTT) colorimetric assay, cell aggression was detected by the transwell cell-invasion assay, and angiogenesis was defined by evaluating the mRNA concentrations of intercellular cell adhesion molecule 1 (ICAM-1), cyclooxygenase 2 (COX-2), matrix metallo peptidase 9 (MMP-9), and vascular endothelial growth factor (VEGF). Attachment, aggression, and angiogenesis (AAA) plays an important role in EMS, and a high dose of the Xiao Liu Fang extract can be used for the treatment of EMS owing to its inhibition of the AAA of endometrial stromal cells. Therefore, in-depth studies targeting the effective mechanisms and targets of traditional Chinese medicine (TCM) are of great significance for the prevention and treatment of EMS.

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

Emerging Issues in AAV-Mediated In Vivo Gene Therapy

In recent years, the number of clinical trials in which adeno-associated virus (AAV) vectors have been used for in vivo gene transfer has steadily increased. The excellent safety profile, together with the high efficiency of transduction of a broad range of target tissues, has established AAV vectors as the platform of choice for in vivo gene therapy. Successful application of the AAV technology has also been achieved in the clinic for a variety of conditions, including coagulation disorders, inherited blindness, and neurodegenerative diseases, among others. Clinical translation of novel and effective "therapeutic products" is, however, a long process that involves several cycles of iterations from bench to bedside that are required to address issues encountered during drug development. For the AAV vector gene transfer technology, several hurdles have emerged in both preclinical studies and clinical trials; addressing these issues will allow in the future to expand the scope of AAV gene transfer as a therapeutic modality for a variety of human diseases. In this review, we will give an overview on the biology of AAV vector, discuss the design of AAV-based gene therapy strategies for in vivo applications, and present key achievements and emerging issues in the field. We will use the liver as a model target tissue for gene transfer based on the large amount of data available from preclinical and clinical studies.

CRTC1-MAML2 fusion-induced lncRNA LINC00473 expression maintains the growth and survival of human mucoepidermoid carcinoma cells

Mucoepidermoid carcinoma (MEC) arises in many glandular tissues and contributes to the most common malignant salivary gland cancers. MEC is specifically associated with a unique t(11;19) translocation and the resulting CRTC1-MAML2 fusion is a major oncogenic driver for MEC initiation and maintenance. However, the molecular basis underlying the CRTC1-MAML2 oncogenic functions remain very limited. Through gene expression profiling analysis, we observed that LINC00473, a long noncoding RNA (lncRNA), was the top down-regulated target in CRTC1-MAML2-depleted human MEC cells. LncRNAs belong to a new class of non-coding RNAs with emerging roles in tumorigenesis and progression, but remain poorly characterized. In this study, we investigated the role of LINC00473 in mediating CRTC1-MAML2 oncogenic activity in human MEC. We found that LINC00473 transcription was significantly induced in human CRTC1-MAML2-positive MEC cell lines and primary MEC tumors, and was tightly correlated with the CRTC1-MAML2 RNA level. LINC00473 induction was dependent on the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Depletion of LINC00473 significantly reduced the proliferation and survival of human MEC cells in vitro and blocked the in vivo tumor growth in a human MEC xenograft model. RNA in situ hybridization analysis demonstrated a predominantly nuclear localization pattern for LINC00473 in human MEC cells. Furthermore, gene expression profiling revealed that LINC00473 depletion resulted in differential expression of genes important in cancer cell growth and survival. LINC00473 likely regulates gene expression in part through its ability to bind to a cAMP signaling pathway component NONO, enhancing the ability of CRTC1-MAML2 to activate CREB-mediated transcription. Our overall results demonstrate that LINC00473 is a downstream target and an important mediator of the CRTC1-MAML2 oncoprotein. Therefore, LINC00473 acts as a promising biomarker and therapeutic target for human CRTC1-MAML2-positive MECs.

Ubiquitin specific peptidase 21 regulates interleukin-8 expression, stem-cell like property of human renal cell carcinoma

USP family proteins play essential roles in cancer cell proliferation and apoptosis and represent as candidate targets for cancer therapeutics. However, the effects and underlying mechanism of USP21 on renal cell carcinomas (RCC) remain unclear. In the present study, we investigate the effects of USP21 on proliferation, invasion and cancer stem cells (CSCs) property of RCC cell lines. As a result, siRNA-mediated depletion of USP21 inhibits cell proliferation, invasion ability and decreases the CSCs percentage of RCC cell lines. Complementarily, forced expression of USP21 leads to increase of tumorigenic properties. In addition, CSCs properties assessed by sphere formation assays demonstrated that depletion of USP21 impair the self-renewal capability of CSCs. Furthermore, decrease USP21 levels is associated with repression of interleukin 8 (IL-8), a chemokine that regulates CSCs characteristics in RCC. Mechanistically, USP21 binds to the promoter region of IL-8 and mediates transcriptional initiation. These data suggest that USP21/IL-8 could be a pair of the critical molecular targets for the development of therapeutic strategies for RCC.

Cyclin-dependent kinase inhibitor 3 (CDKN3) plays a critical role in prostate cancer via regulating cell cycle and DNA replication signaling

Cyclin-dependent kinase inhibitor 3 (CDKN3) is proved to be associated with the progressing of many cancers. Whereas, its biological effects on prostate cancer (PC) are less understood. To investigate the functional mechanism of CDKN3 in PC, we examined the expression of CDKN3 in PC tissues and analyzed the disease free survival time of patients. We then transfected LNCaP and PC3 cells with siRNA-CDKN3 to silence CDKN3, and transfected 22RV1 and VCaP cells with full length CDKN3 cDNA for CDKN3 over-expression. Cell growth of these transfected cells were analyzed using CCK-8 assay. And transfected LNCaP and PC3 cells were further submitted to cell cycle, apoptosis, invasion and endogenous protein expression assays. We found that CDKN3 was highly expressed in PC and negatively correlated with disease relapse. And CDKN3 positively control the cell proliferation in prostate carcinoma cell lines. Knockdown of CDKN3 significantly promoted G1 phase arrest, elevated apoptosis rates, and suppressed cell invasion in both LNCaP and PC3 cells. Moreover, in vivo data showed that knockdown of CDKN3 expression dramatically inhibited the PC3 tumor growth in nude mouse model. Gene set enrichment analysis (GSEA) showed that cell cycle and DNA replication signaling were related with elevated CDKN3 expression. And results of western blot showed that the depletion of CDKN3 down-regulated the expression levels of cell cycle- and DNA replication-related proteins. In conclusion, our results highlight the importance of CDKN3 in PC and provide new insights into diagnostics and therapeutics of the PC.

Antitumor effects of pristimerin on human osteosarcoma cells in vitro and in vivo

There are very few treatments for musculoskeletal tumors, compared to other cancers; thus, novel therapeutic drugs are needed. Pristimerin (PM) is a triterpene compound isolated from plant extracts that reportedly has antitumor effects on various cancers, such as of the breast and prostate. The purpose of this study was to evaluate the antitumor effects of PM on human osteosarcoma cells. Treatment of the human osteosarcoma cell lines, MNNG and 143B, with PM led to a dose-dependent decrease in cell viability. The effects of PM on apoptosis were evaluated with the Annexin V/propidium iodide assay and analysis of caspases 3, 8, and 9 activities. Western blot analysis showed that PM caused a decrease in the expression of Akt, mTOR, and NF-κB. The volumes and weights of human osteosarcoma xenografts decreased significantly with PM treatment. The results of this study revealed that PM can inhibit human osteosarcoma growth in vitro and in vivo, and may be a novel therapeutic agent for the disease.

Berberine prevents the apoptosis of mouse podocytes induced by TRAF5 overexpression by suppressing NF-κB activation

Berberine (BBR) has previously been found to exert beneficial effects on renal injury in experimental rats. However, the mechanisms underlying these effects are not yet fully understood. Tumor necrosis factor (TNF) receptor-associated factor 5 (TRAF5) has been demonstrated to mediate the activation of nuclear factor-κB (NF-κB), which has been implicated in the pathogenesis of chronic kidney disease (CKD). The aim of this study was to investigate the effects of BBR on kidney injury and the activation of the NF-κB signaling pathway in mouse podocytes. TRAF5 was found to be overexpressed in patients with CKD and chronic renal failure (CRF) (data obtained from the dataset GSE48944, as well as from patients at Shuguang Hospital). TRAF5 overexpression significantly inhibited cell viability and induced the apoptosis of mouse podocytes. However, BBR prevented the decrease in cell viability and the apoptosis induced by TRAF5 overexpression. The NF-κB inhibitor, caffeic acid phenethyl ester (CAPE), mimicked the protective effects of BBR, as evidenced by the increased expression of nephrin and podocin, and the decreased the expression of caspase-3 and the ratio of Bax/Bcl-2. Moreover, BBR prevented the decrease in cell viability decrease and the apoptosis induced by TNF-α, interleukin (IL)-6 and lipopolysaccharide (LPS). Taken together, our data indicate that BBR exerts protective effects against CRF partly through the TRAF5-mediated activation of the NF-κB signaling pathway in mouse podocytes.

Emodin alleviates severe acute pancreatitis-associated acute lung injury by decreasing pre-B-cell colony-enhancing factor expression and promoting polymorphonuclear neutrophil apoptosis

The present study aimed to evaluate the protective effects of emodin on severe acute pancreatitis (SAP)‑associated acute lung injury (ALI), and investigated the possible mechanism involved. SAP was induced in Sprague‑Dawley rats by retrograde infusion of 5% sodium taurocholate (1 ml/kg), after which, rats were divided into various groups and were administered emodin, FK866 [a competitive inhibitor of pre‑B‑cell colony‑enhancing factor (PBEF)] or dexamethasone (DEX). DEX was used as a positive control. Subsequently, PBEF expression was detected in polymorphonuclear neutrophils (PMNs) isolated from rat peripheral blood by reverse transcription‑quantitative polymerase chain reaction and western blotting. In addition, histological alterations, apoptosis in lung/pancreatic tissues, apoptosis of peripheral blood PMNs and alterations in the expression of apoptosis‑associated proteins were examined by hematoxylin and eosin staining, terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling assay, Annexin V/propidium iodide (PI) assay and western blotting, respectively. Serum amylase activity and wet/dry (W/D) weight ratios were also measured. An in vitro study was also conducted, in which PMNs were obtained from normal Sprague‑Dawley rats and were incubated with emodin, FK866 or DEX in the presence of lipopolysaccharide (LPS). Apoptosis of PMNs and the expression levels of apoptosis‑associated proteins were examined in cultured PMNs in vitro by Annexin V/PI assay and western blotting, respectively. The results demonstrated that emodin, FK866 and DEX significantly downregulated PBEF expression in peripheral blood PMNs. In addition, emodin, FK866 and DEX reduced serum amylase activity, decreased lung and pancreas W/D weight ratios, alleviated lung and pancreatic injuries, and promoted PMN apoptosis by regulating the expression of apoptosis‑associated proteins: Fas, Fas ligand, B‑cell lymphoma (Bcl)‑2‑associated X protein, cleaved caspase‑3 and Bcl‑extra‑large. In addition, the in vitro study demonstrated that emodin, FK866 and DEX significantly reversed the LPS‑induced decrease of apoptosis in PMNs by regulating the expression of apoptosis‑associated proteins. In conclusion, the present study demonstrated that emodin may protect against SAP‑associated ALI by decreasing PBEF expression, and promoting PMN apoptosis via the mitochondrial and death receptor apoptotic pathways.

Estrogen-related receptor α participates transforming growth factor-β (TGF-β) induced epithelial-mesenchymal transition of osteosarcoma cells

Osteosarcoma patients often exhibit pulmonary metastasis, which results in high patient mortality. Understanding the mechanisms of advanced metastasis in osteosarcoma cell is important for the targeted treatment and drug development. Our present study revealed that transforming growth factor-β (TGF-β) treatment can significantly promote the in vitro migration and invasion of human osteosarcoma MG-63 and HOS cells. The loss of epithelial characteristics E-cadherin (E-Cad) and up regulation of mesenchymal markers Vimentin (Vim) suggested TGF-β induced epithelial-mesenchymal transition (EMT) of osteosarcoma cells. TGF-β treatment obviously increased the expression of Snail, a key EMT-related transcription factor, in both MG-63 and HOS cells. Silencing of Snail markedly attenuated TGF-β induced down regulation of E-cad and up regulation of Vim. TGF-β treatment also significantly increased the expression and nuclear translocation of estrogen-related receptors α (ERRα), while had no obvious effect on the expression of ERα, ERβ, or ERRγ. Knock down of ERRα or its inhibitor XCT-790 significantly attenuated TFG-β induced EMT and transcription of Snail in osteosarcoma cells. Collectively, our present study revealed that TGF-β treatment can trigger the EMT of osteosarcoma cells via ERRα/Snail pathways. Our data suggested that ERRα/Snail pathways might be potential therapeutic targets of metastasis of osteosarcoma cells.

High-Efficiency Transduction of Primary Human Hematopoietic Stem/Progenitor Cells by AAV6 Vectors: Strategies for Overcoming Donor-Variation and Implications in Genome Editing

We have reported that of the 10 commonly used AAV serotype vectors, AAV6 is the most efficient in transducing primary human hematopoietic stem/progenitor cells (HSPCs). However, the transduction efficiency of the wild-type (WT) AAV6 vector varies greatly in HSPCs from different donors. Here we report two distinct strategies to further increase the transduction efficiency in HSPCs from donors that are transduced less efficiently with the WT AAV6 vectors. The first strategy involved modifications of the viral capsid proteins where specific surface-exposed tyrosine (Y) and threonine (T) residues were mutagenized to generate a triple-mutant (Y705 + Y731F + T492V) AAV6 vector. The second strategy involved the use of ex vivo transduction at high cell density. The combined use of these strategies resulted in transduction efficiency exceeding ~90% in HSPCs at significantly reduced vector doses. Our studies have significant implications in the optimal use of capsid-optimized AAV6 vectors in genome editing in HSPCs.

Dioscin inhibits gastric tumor growth through regulating the expression level of lncRNA HOTAIR

Background

As a member of non-coding RNAs family, long non-coding RNAs’ functions in cancer needs to be further investigated. It has been indicated that the functions of Hox transcript antisense intergenic RNA (lncRNA: HOTAIR) include reprogramming chromatin organization and promoting tumor metastasis such as breast and colorectal tumor. The aim of this study is to investigate the functions of Hox in gastric cancer.

Methods

In the present study, the expression level of HOTAIR was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 20 gastric cancer tissues and 20 normal tissues was included. All clinical data were analyzed retrospectively. The CCK-8 and colony formation assay was used to identify if the knockdown of HOTAIR have an influence on gastric cancer cell lines.

Results

Compared with normal tissues, higher expression level of HOTAIR was found in gastric cancer tissues. Dioscin inhibits proliferation of the three gastric cancer cell lines and decrease HOTAIR expression.

Conclusions

The expression of HOTAIR is up regulated in gastric cancer and gastric cancer cell lines, dioscin inhibits the proliferation of three gastric cancer cell lines and the anti-tumor effect of dioscin may partly depend on the down regulation of HOTAIR.

High-Density Recombinant Adeno-Associated Viral Particles are Competent Vectors for In Vivo Transduction

Recombinant adeno-associated viral (rAAV) vectors have recently achieved clinical successes in human gene therapy. However, the commonly observed, heavier particles found in rAAV preparations have traditionally been ignored due to their reported low in vitro transduction efficiency. In this study, the biological properties of regular and high-density rAAV serotype 8 vectors, rAAV^RD and rAAV^HD, were systemically compared. Results demonstrated that both rAAV^RD and rAAV^HD exhibited similar DNA packaging profiles, while rAAV^HD capsids contained fewer VP1 and VP2 proteins, indicating that the rAAV^HD particles contained a higher DNA/protein ratio than that of rAAV^RD particles. Dynamic light scattering and transmission electron microscopy data revealed that the diameter of rAAV^HD was smaller than that of rAAV^RD. In vitro, rAAV^HD was two- to fourfold less efficient in transduction compared with rAAV^RD. However, the transduction performance of rAAV^HD and rAAV^RD was similar in vivo. No significant difference in neutralizing antibody formation against rAAV^RD and rAAV^HD was observed, suggesting that the surface epitopes of rAAV^RD and rAAV^HD are congruent. In summary, the results of this study demonstrate that rAAV^RD and rAAV^HD are equally competent for in vivo transduction, despite their difference in vitro. Therefore, the use of rAAV^HD vectors in human gene therapy should be further evaluated.

The m(6)A Methyltransferase METTL3 Promotes Translation in Human Cancer Cells

METTL3 is an RNA methyltransferase implicated in mRNA biogenesis, decay, and translation control through N(6)-methyladenosine (m(6)A) modification. Here we find that METTL3 promotes translation of certain mRNAs including epidermal growth factor receptor (EGFR) and the Hippo pathway effector TAZ in human cancer cells. In contrast to current models that invoke m(6)A reader proteins downstream of nuclear METTL3, we find METTL3 associates with ribosomes and promotes translation in the cytoplasm. METTL3 depletion inhibits translation, and both wild-type and catalytically inactive METTL3 promote translation when tethered to a reporter mRNA. Mechanistically, METTL3 enhances mRNA translation through an interaction with the translation initiation machinery. METTL3 expression is elevated in lung adenocarcinoma and using both loss- and gain-of-function studies, we find that METTL3 promotes growth, survival, and invasion of human lung cancer cells. Our results uncover an important role of METTL3 in promoting translation of oncogenes in human lung cancer.

mTORC1 is necessary but mTORC2 and GSK3β are inhibitory for AKT3-induced axon regeneration in the central nervous system

Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration.

DOI:http://dx.doi.org/10.7554/eLife.14908.001

The central nervous system consists of the neurons that make up the brain and spinal cord. An important part of a neuron is the long, slender projection along which electrical signals travel, called the axon. In the central nervous system of mammals, damaged axons cannot regrow, which is why spinal injuries or optic nerve injuries can result in life-long neuronal deficits.

Recent studies have found that activating a particular signaling pathway in central nervous system neurons causes their axons to regenerate. A key protein in this pathway is called AKT. Several signaling cascades are triggered by AKT to regulate cell survival and growth, but it was not known how the different branches of the AKT pathway are involved in axon regeneration.

Miao, Yang et al. have now investigated AKT’s role in axon regeneration using a range of approaches to manipulate signaling in damaged mouse neurons. This revealed that a particular form of AKT (called AKT3) causes damaged axons to regenerate to a greater extent than other forms of this protein. This response depends on two parallel pathways: one in which AKT3 activates a protein complex called mTORC1, and one where AKT3 inhibits a protein called GSK3β. In addition, another protein complex called mTORC2, which is closely related to mTORC1, helps to inhibit the activity of AKT3 on GSK3β and hence inhibits axon regeneration.

These findings reveal that a complex balancing mechanism, with AKT at its center, coordinates the many signals that regulate axon regeneration. Future studies into this system could ultimately help to develop new treatments for brain and spinal injuries.

DOI:http://dx.doi.org/10.7554/eLife.14908.002

Histone deacetylase inhibitors suppress mutant p53 transcription via HDAC8/YY1 signals in triple negative breast cancer cells

There is an urgent need to investigate the potential targeted therapy approach for triple-negative breast cancer (TNBC). Our present study reveals that histone deacetylase inhibitors (HDACIs) suberoyl anilide hydroxamic acid (SAHA) and sodium butyrate (NaB) significantly inhibit cell proliferation, arrest cell cycle at G0/G1 phase, and induce mitochondrial related apoptosis of TNBC cells. Further, SAHA and NaB decrease the phosphorylation, protein and mRNA levels of mutant p53 (mtp53) in TNBC cells. While SAHA or NaB has no similar inhibition effect on wild type p53 (wtp53). The inhibition apparently occurs at the level of transcription because the down regulation of precursor p53 transcription is much more rapid (less than 2h) and sharp than that of mature p53. The knockdown of HDAC8, while not HDAC6, inhibits the transcription of mtp53 in TNBC cells. The luciferase assay and ChIP analysis reveal that both SAHA and NaB can reduce the binding of transcription factor Yin Yang 1 (YY1) with the -102 to -96 position of human p53 promoter. Knockdown of YY1 also significantly inhibits the transcription of mtp53 in TNBC cells. Further, SAHA and NaB can inhibit the association of HDAC8 and YY1, increase acetylation of residues 170-200 of YY1, then decrease its transcription activities, and finally suppress YY1 induced p53 transcription. Together, our data establish that SAHA and NaB can be considered as drug candidates for TNBC patients, and HDAC8/YY1/mtp53 signals act as an important target for TNBC treatment.

Improvement of the cytotoxic T lymphocyte response against hepatocellular carcinoma by transduction of cancer cells with an adeno-associated virus carrying the interferon-γ gene

Dendritic cell (DC)-based antigen-targeted immunotherapy may offer effective adjuvant therapy for hepatocellular carcinoma (HCC), in which cytotoxic T lymphocytes (CTLs) are key. However, in a number of cases, the activity of CTLs is completely inhibited due to the downregulated expression of major human leukocyte antigen (HLA) class I molecules by HCC cells. The aim of the present study was to overcome this issue. Hep3B cells were transduced by HCC‑specific recombinant adeno‑associated virus (rAAV) carrying human α‑fetoprotein promoter (AFPp) and the interferon‑γ (IFN‑γ) gene (rAAV/AFPp‑IFN‑γ). rAAV carrying the cytomegalovirus promoter (CMVp) and human α‑fetoprotein (AFP) gene (rAAV/CMVp‑AFP) was used to transduce professional antigen‑presenting DCs for the purpose of stimulating a CTL response. It was observed that transduction of DCs with rAAV/CMVp‑AFP resulted in: (i) AFP and interleukin‑12 expression; (ii) high expression levels of cluster of differentiation (CD)80, CD83, CD86, CD40, HLA‑death receptor and CD1a; (iii) T cell populations with marked IFN‑γ expression; (iv) a high percentage of CD69+/CD8+ T cells; and (v) the activity of CTLs against HLA‑A2‑expressing Hep3B cells. The transduction of Hep3B cells with rAAV/AFPp‑IFN‑γ resulted in: (i) IFN‑γ expression; (ii) upregulated expression of HLA‑A2; and (iii) an improved CTL response against HLA‑A2‑deficient Hep3B cells. rAAV/CMVp‑AFP‑transduced DCs elicited an AFP‑specific and HLA‑class I‑restricted CTL response against Hep3B cells. In conclusion, it was shown that the transduction of Hep3B with rAAV/AFPp-IFN-γ upregulated the expression of HLA-A2 and improved the sensitivity to CTL response.

Efficient and Targeted Transduction of Nonhuman Primate Liver With Systemically Delivered Optimized AAV3B Vectors

Recombinant adeno-associated virus serotype 3B (rAAV3B) can transduce cultured human liver cancer cells and primary human hepatocytes efficiently. Serine (S)- and threonine (T)-directed capsid modifications further augment its transduction efficiency. Systemically delivered capsid-optimized rAAV3B vectors can specifically target cancer cells in a human liver cancer xenograft model, suggesting their potential use for human liver-directed gene therapy. Here, we compared transduction efficiencies of AAV3B and AAV8 vectors in cultured primary human hepatocytes and cancer cells as well as in human and mouse hepatocytes in a human liver xenograft NSG-PiZ mouse model. We also examined the safety and transduction efficacy of wild-type (WT) and capsid-optimized rAAV3B in the livers of nonhuman primates (NHPs). Intravenously delivered S663V+T492V (ST)-modified self-complementary (sc) AAV3B-EGFP vectors led to liver-targeted robust enhanced green fluorescence protein (EGFP) expression in NHPs without apparent hepatotoxicity. Intravenous injections of both WT and ST-modified rAAV3B.ST-rhCG vectors also generated stable super-physiological levels of rhesus chorionic gonadotropin (rhCG) in NHPs. The vector genome predominantly targeted the liver. Clinical chemistry and histopathology examinations showed no apparent vector-related toxicity. Our studies should be important and informative for clinical development of optimized AAV3B vectors for human liver-directed gene therapy.

Nanoparticle-mediated rhodopsin cDNA but not intron-containing DNA delivery causes transgene silencing in a rhodopsin knockout model

Previously, we compared the efficacy of nanoparticle (NP)-mediated intron-containing rhodopsin (sgRho) vs. intronless cDNA in ameliorating retinal disease phenotypes in a rhodopsin knockout (RKO) mouse model of retinitis pigmentosa. We showed that NP-mediated sgRho delivery achieved long-term expression and phenotypic improvement in RKO mice, but not NP housing cDNA. However, the protein level of the NP-sgRho construct was only 5-10% of wild-type at 8 mo postinjection. To have a better understanding of the reduced levels of long-term expression of the vectors, in the present study, we evaluated the epigenetic changes of subretinal delivering NP-cDNA vs. NP-sgRho in the RKO mouse eyes. Following the administration, DNA methylation and histone status of specific regions (bacteria plasmid backbone, promoter, rhodopsin gene, and scaffold/matrix attachment region) of the vectors were evaluated at various time points. We documented that epigenetic transgene silencing occurred in vector-mediated gene transfer, which were caused by the plasmid backbone and the cDNA of the transgene, but not the intron-containing transgene. No toxicity or inflammation was found in the treated eyes. Our results suggest that cDNA of the rhodopsin transgene and bacteria backbone interfered with the host defense mechanism of DNA methylation-mediated transgene silencing through heterochromatin-associated modifications.

Prevalence of neutralizing antibodies against liver-tropic adeno-associated virus serotype vectors in 100 healthy Chinese and its potential relation to body constitutions

Recombinant adeno-associated virus (rAAV) serotype 2, 3 and 8 vectors are the most promising liver-tropic AAV serotype vectors. Liver diseases are significant problems in China. However, to date, few studies on AAV neutralizing antibodies (Nabs) were working with the Chinese population or with the rAAV3 vectors. The present study aimed to determine the prevalence of Nabs in Chinese population against wild-type AAV2, AAV3 and AAV8 capsids as well as additional two AAV3 variants. In addition, we performed a preliminary analysis to investigate the potential influence of traditional Chinese medicine body constitutions on AAV Nabs. Our work demonstrated that the majority of healthy Chinese subjects were positive for AAV Nabs, with the order of AAV2>AAV3=AAVLK03>AAV8. There was no difference between: 1) AAV3 and its variants; 2) male and female subjects; and 3) different age cohorts (≤35, 36-50, and ≥51 years old). People in the Qi-deficiency constitution had significantly increased AAV8 Nabs than people in the Gentleness constitution. Our studies may have impact on the future clinical design of AAV-based gene therapy in the Chinese population.

Overexpression of HPV16 E6/E7 mediated HIF-1α upregulation of GLUT1 expression in lung cancer cells

High-risk human papillomavirus (HPV) infection may play an important role in non-small cell lung carcinoma (NSCLC) development. However, some recent studies have proved that it was not directly associated with lung cancer. The aim of this study was to evaluate the underlying molecular mechanism that HPV16 regulate the expression of GLUT1 and may promote the development of lung cancer. HPV16, HIF-1α, and GLUT1 were detected in pleural effusions of patients with lung cancer (n = 95) and with benign lung disease (n = 55) by immunocytochemistry. Western blotting and qRT-PCR were used to detect the expression chances of HPV16 E6/E7, HIF-1α, and GLUT1 in lung cancer cells. HPV16, HIF-1α, and GLUT1 were significantly more likely to be expressed in the malignant group than in the benign group as detected by immunocytochemistry (ICC), and HIF-1α was significantly correlated with HPV16 or GLUT1 in the malignant group (P < 0.01). Expression changes of E6 and E7 significantly promoted the protein expression of HIF-1α, the expression of both protein and mRNA of GLUT1, but had no effect on the expression of HIF-1α mRNA in lung cancer cells. After inhibition of HIF-1α, it obviously downregulated the expression of both protein and mRNA of GLUT1 in lung cancer cells. E6 and E7 regulated the expression of GLUT1 may be due to the mediation of HIF-1α in lung cancer cells. These results suggest that both E6 and E7 play the important role in the regulation of Warburg effect and may be a valuable therapeutic target for HPV-related cancer.

Site-Directed Mutagenesis of Surface-Exposed Lysine Residues Leads to Improved Transduction by AAV2, But Not AAV8, Vectors in Murine Hepatocytes In Vivo

The ubiquitin-proteasome pathway plays a critical role in the intracellular trafficking of recombinant adeno-associated virus 2 (AAV2) vectors, which negatively impacts the transduction efficiency of these vectors. Because ubiquitination occurs on lysine (K) residues, we performed site-directed mutagenesis where we replaced each of 10 surface-exposed K residues (K258, K490, K507, K527, K532, K544, K549, K556, K665, and K706) with glutamic acid (E) because of similarity of size and lack of recognition by modifying enzymes. The transduction efficiency of K490E, K544E, K549E, and K556E scAAV2 vectors increased in HeLa cells in vitro up to 5-fold compared with wild-type (WT) AAV2 vectors, with the K556E mutant being the most efficient. Intravenous delivery of WT and K-mutant ssAAV2 vectors further corroborated these results in murine hepatocytes in vivo. Because AAV8 vectors transduce murine hepatocytes exceedingly well, and because some of the surface-exposed K residues are conserved between these serotypes, we generated and tested two single mutants (K547E and K569E), and one double-mutant (K547 + 569E) AAV8 vector. However, no significant increase in the transduction efficiency of any of these mutant AAV8 vectors was observed in murine hepatocytes in vivo. These studies suggest that although targeting the surface-exposed K residues is yet another strategy to improve the transduction efficiency of AAV vectors, phenotypic outcome is serotype specific.

Development of novel AAV serotype 6 based vectors with selective tropism for human cancer cells

Viral vectors-based gene therapy is an attractive alternative to common anti-cancer treatments. In the present studies, AAV serotype 6 vectors were identified to be particularly effective in the transduction of human prostate (PC3), breast (T47D) and liver (Huh7) cancer cells. Next, we developed chimeric AAV vectors with Arg-Gly-Asp (RGD) peptide incorporated into the viral capsid to enable specific targeting of integrin-overexpressing malignant cells. These AAV6-RGD vectors improved transduction efficiency approximately 3-fold compared with wild-type AAV6 vectors by enhancing the viral entry into the cells. We also observed that transduction efficiency significantly improved, up to approximately 5-fold, by the mutagenesis of surface-exposed tyrosine and threonine residues involved in the intracellular trafficking of AAV vectors. Therefore, in our study, the AAV6-Y705-731F+T492V vector was identified as the most efficient. The combination of RGD peptide, tyrosine and threonine mutations on the same AAV6 capsid further increased the transduction efficiency, approximately 8-fold in vitro. In addition, we mutated lysine (K531E) to impair the affinity of AAV6 vectors to heparan sulfate proteoglycan. Finally, we showed a significant increase in both specificity and efficiency of AAV6-RGD-Y705-731F+T492V+K531E vectors in a xenograft animal model in vivo. In summary, the approach described here can lead to the development of AAV vectors with selective tropism to human cancer cells.

Electro-acupuncture exerts beneficial effects against cerebral ischemia and promotes the proliferation of neural progenitor cells in the cortical peri-infarct area through the Wnt/β-catenin signaling pathway

Electro-acupuncture (EA) is a novel therapy based on combining traditional acupuncture with modern electrotherapy, and it is currently being investigated as a treatment for ischemic stroke. In the present study, we aimed to investigate the mechanisms through which EA regulates the proliferation of neural progenitor cells (NPCs) in the cortical peri-infarct area after stroke. The neuroprotective effects of EA on ischemic rats were evaluated by determining the neurological deficit scores and cerebral infarct volumes. The proliferation of the NPCs and the activation of the Wnt/β-catenin signaling pathway in the cortical peri-infarct area were examined. Our results revealed that EA significantly alleviated neurological deficits, reduced the infarct volume and enhanced NPC proliferation [nestin/glial fibrillary acidic protein (GFAP)-double positive] in the cortex of rats subjected to middle cerebral artery occlusion (MCAO). Moreover, the Wnt1 and β-catenin mRNA and protein levels were increased, while glycogen synthase kinase-3 (GSK3) transcription was suppressed by EA. These results suggest that the upregulatory effects of EA on the Wnt/β-catenin signaling pathway may promote NPC proliferation in the cortical peri-infarct area after stroke, consequently providing a therapeutic effect against cerebral ischemia.

Selective in vivo targeting of human liver tumors by optimized AAV3 vectors in a murine xenograft model

Current challenges for recombinant adeno-associated virus (rAAV) vector-based cancer treatment include the low efficiency and the lack of specificity in vivo. rAAV serotype 3 (rAAV3) vectors have previously been shown to be ineffective in normal mouse tissues following systemic administration. In the present study, we report that rAAV3 vectors can efficiently target and transduce various human liver cancer cells in vivo. Elimination of specific surface-exposed serine and threonine residues on rAAV3 capsids results in further augmentation in the transduction efficiency of these vectors, without any change in the viral tropism and cellular receptor interactions. In addition, we have identified a potential chemotherapy drug, shikonin, as a multifunctional compound to inhibit liver tumor growth as well as to significantly enhance the efficacy of rAAV vector-based gene therapy in vivo. Furthermore, we also document that suppression of tumorigenesis in a human liver cancer xenograft model can be achieved through systemic administration of the optimized rAAV3 vectors carrying a therapeutic gene, and shikonin at a dose that does not lead to liver damage. Our research provides a novel means to achieve not only targeted delivery but also the potential for gene therapy of human liver cancer.

Chronic Dietary Administration of the Glycolytic Inhibitor 2-Deoxy-D-Glucose (2-DG) Inhibits the Growth of Implanted Ehrlich's Ascites Tumor in Mice

Background

Dietary energy restriction (DER) has been well established as a potent anticancer strategy. Non-adoption of restricted diet for an extended period has limited its practical implementation in humans with a compelling need to develop agents that mimic effects similar to DER, without reduction in actual dietary intake. Glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has recently been shown to possess potential as an energy restriction mimetic agent (ERMA). In the present study we evaluated the effect of dietary 2-DG administration on a mouse tumor model, with a focus on several potential mechanisms that may account for the inhibition of tumorigenesis.

Methodology/Principal Findings

Swiss albino strain ‘A’ mice were administered with 0.2% and 0.4% w/v 2-DG in drinking water for 3 months prior to tumor implantation (Ehrlich’s ascites carcinoma; EAC) and continued till the termination of the study with no adverse effects on general physiology and animal growth. Dietary 2-DG significantly reduced the tumor incidence, delayed the onset, and compromised the tumor growth along with enhanced survival. We observed reduced blood glucose and serum insulin levels along with decreased proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine positive (BrdU⁺) tumor cells in 2-DG fed mice. Also, reduced levels of certain key players of metabolic pathways such as phosphatidylinositol 3-kinase (PI3K), phosphorylated-Akt and hypoxia inducible factor-1 alpha (HIF-1α) were also noted in tumors of 2-DG fed mice. Further, decrease in CD4⁺/CD8⁺ ratio and T-regulatory cells observed in 2-DG fed mice suggested enhanced antitumor immunity and T cell effector function.

Conclusion/Significance

These results strongly suggest that dietary 2-DG administration in mice, at doses easily achievable in humans, suitably modulates several pleotrophic factors mimicking DER and inhibits tumorigenesis, emphasizing the use of ERMAs as a promising cancer preventive strategy.

Shikonin Induces Apoptosis, Necrosis, and Premature Senescence of Human A549 Lung Cancer Cells through Upregulation of p53 Expression

Shikonin, a natural naphthoquinone pigment isolated from Lithospermum erythrorhizon, has been reported to suppress growth of various cancer cells. This study was aimed to investigate whether this chemical could also inhibit cell growth of lung cancer cells and, if so, works via what molecular mechanism. To fulfill this, A549 lung cancer cells were treated with shikonin and then subjected to microscopic, biochemical, flow cytometric, and molecular analyses. Compared with the controls, shikonin significantly induced cell apoptosis and reduced proliferation in a dose-dependent manner. Specially, lower concentrations of shikonin (1-2.5 μg/mL) cause viability reduction; apoptosis and cellular senescence induction is associated with upregulated expressions of cell cycle- and apoptotic signaling-regulatory proteins, while higher concentrations (5-10 μg/mL) precipitate both apoptosis and necrosis. Treatment of cells with pifithrin-α, a specific inhibitor of p53, suppressed shikonin-induced apoptosis and premature senescence, suggesting the role of p53 in mediating the actions of shikonin on regulation of lung cancer cell proliferation. These results indicate the potential and dose-related cytotoxic actions of shikonin on A549 lung cancer cells via p53-mediated cell fate pathways and raise shikonin a promising adjuvant chemotherapeutic agent for treatment of lung cancer in clinical practice.

Protective effect of tea polyphenol ophthalmic gel on lens epithelial cells in rabbits with silicone oil tamponade after vitrectomy

Purpose. The aim of this study was to investigate the effect of tea polyphenols (TP) ophthalmic gel on lens epithelial cells (LECs) in rabbits with silicone oil tamponade after vitrectomy. Methods. In this study, unilateral vitrectomy with silicone oil tamponade was performed using 2-month-old New Zealand white rabbits (n = 72); meanwhile, age-matched nonoperated rabbits (n = 18) were used as controls. The TP ophthalmic gel was administered topically in the surgical eyes till they were sacrificed. On days 45 and 90 after operation, the levels of reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨm), and apoptosis of LECs were analyzed, respectively. Meanwhile, caspase-3 mRNA and protein levels were also determined. Results. The results indicate that the levels of ROS and apoptosis were elevated for LECs in rabbits after operation, whereas ΔΨm was decreased. Caspase-3 was apparently increased at both mRNA and protein levels. Treatment of TP ophthalmic gel could reduce the generation of ROS, maintain ΔΨm, inhibit the overexpression of caspase-3, and thus decrease the apoptosis of LECs of rabbits after operation. Conclusions. TP ophthalmic gel can efficiently inhibit caspase-3 overexpression, reduce the apoptosis of LECs, and prevent LECs from damage. Our result provides a new approach to prevent the development of complicated cataract after vitrectomy.

Enhanced transgene expression from recombinant single-stranded D-sequence-substituted adeno-associated virus vectors in human cell lines in vitro and in murine hepatocytes in vivo

We have previously reported that the removal of a 20-nucleotide sequence, termed the D sequence, from both ends of the inverted terminal repeats (ITRs) in the adeno-associated virus serotype 2 (AAV2) genome significantly impairs rescue, replication, and encapsidation of the viral genomes (X. S. Wang, S. Ponnazhagan, and A. Srivastava, J Mol Biol 250:573-580, 1995; X. S. Wang, S. Ponnazhagan, and A. Srivastava, J Virol 70:1668-1677, 1996). Here we describe that replacement of only one D sequence in either ITR restores each of these functions, but DNA strands of only single polarity are encapsidated in mature progeny virions. Since most commonly used recombinant AAV vectors contain a single-stranded DNA (ssDNA), which is transcriptionally inactive, efficient transgene expression from AAV vectors is dependent upon viral second-strand DNA synthesis. We have also identified a transcription suppressor sequence in one of the D sequences, which shares homology with the binding site for the cellular NF-κB-repressing factor (NRF). The removal of this D sequence from, and replacement with a sequence containing putative binding sites for transcription factors in, single-stranded AAV (ssAAV) vectors significantly augments transgene expression both in human cell lines in vitro and in murine hepatocytes in vivo. The development of these genome-modified ssAAV vectors has implications not only for the basic biology of AAV but also for the optimal use of these vectors in human gene therapy.

IMPORTANCE

The results of the studies described here not only have provided novel insights into some of the critical steps in the life cycle of a human virus, the adeno-associated virus (AAV), that causes no known disease but have also led to the development of novel recombinant AAV vectors which are more efficient in allowing increased levels of gene expression. Thus, these studies have significant implications for the potential use of these novel AAV vectors in human gene therapy.

Yiqi formula enhances the antitumor effects of erlotinib for treatment of triple-negative breast cancer xenografts

Yiqi formula (YF), a traditional herbal prescription, has long been used to treat triple-negative breast cancer (TNBC) patients. The present study aims to investigate the effects and the related mechanism of YF for treatment of TNBC xenografts. MDA-MB-231 (human TNBC) cells were subcutaneously injected into the second mammary fat pad of 40 female nude mice, which were divided into four groups: control, erlotinib (an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor), YF, and combination (YF plus erlotinib). All treatments were administered orally for 30 days. Inhibition rate of tumor weight by erlotinib, YF, and the combination was 26.47%, 17.24%, and 39.15%, respectively. Western blotting showed that YF, erlotinib, and the combination downregulated p-EGFR (P < 0.01) and p-Akt1 (pT308) (P < 0.05) and upregulated PTEN compared with control, and the combination was more efficacious than erlotinib alone (P < 0.05). Similar results were detected by immunohistochemistry. Real-time quantitative PCR showed that YF, erlotinib, and the combination increased PTEN mRNA (P < 0.05, P < 0.01) compared with control, and the combination was more efficacious than erlotinib alone (P < 0.05). In conclusion, YF can regulate the main components of the PI3K/Akt pathway in TNBC xenografts. When YF was used in combination with erlotinib, it enhanced the antitumor effects of erlotinib on TNBC xenografts. These findings suggest that YF is suitable to use for the treatment of TNBC patients.

The Effects of Uygur Herb Hyssopus officinalis L. on the Process of Airway Remodeling in Asthmatic Mice

It has been proved that Uygur herb Hyssopus offcinalis L. could affect the levels of some cytokines (such as IL-4, IL-6, IL-17, and IFN-γ) in asthmatic mice. By detection of the expressions of MMP-9 and TIMP-1 and the morphological changes, the aim of this research is to reveal the mechanism of Uygur herb Hyssopus offcinalis L. in the process of airway remodeling. It was observed that the expressions of MMP-9 and TIMP-1 increased, but the ratio of MMP-9/TIMP-1 decreased in airway remodeling group. However, the expression of both MMP-9 and TIMP-1 decreased after being treated with dexamethasone and Hyssopus offcinalis L., accompanied by the relieved pathological changes, including collagen deposition, mucus secretion, and smooth muscle proliferation. It is suggested that Uygur herb Hyssopus offcinalis L. could inhibit airway remodeling by correcting imbalance of MMP-9/TIMP-1 ratio.

Pristimerin, a naturally occurring triterpenoid, protects against autoimmune arthritis by modulating the cellular and soluble immune mediators of inflammation and tissue damage

Rheumatoid arthritis (RA) is a chronic autoimmune disorder affecting the synovial joints. The currently available drugs for RA are effective only in a proportion of patients and their prolonged use is associated with severe adverse effects. Thus, new anti-arthritic agents are being sought. We tested Pristimerin, a naturally occurring triterpenoid, for its therapeutic activity against rat adjuvant arthritis. Pristimerin effectively inhibited both arthritic inflammation and cartilage and bone damage in the joints. Pristimerin-treated rats exhibited a reduction in the pro-inflammatory cytokines (IL-6, IL-17, IL-18, and IL-23) and the IL-6/IL-17-associated transcription factors (pSTAT3 and ROR-γt), coupled with an increase in the immunomodulatory cytokine IL-10. Also increased was IFN-γ, which can inhibit IL-17 response. In addition, the Th17/Treg ratio was altered in favor of immune suppression and the RANKL/OPG ratio was skewed towards anti-osteoclastogenesis. This is the first report on testing Pristimerin in arthritis. We suggest further evaluation of Pristimerin in RA patients.

Development and Challenges of Nanovectors in Gene Therapy

In recent years, hundreds of genes have been linked to a variety of human diseases, and the field of gene therapy has emerged as a way to treat this wide range of diseases. The main goal of gene therapy is to find a gene delivery vehicle that can successfully target diseased cells and deliver therapeutic genes directly to their cellular compartment. The two main types of gene delivery vectors currently being investigated in clinical trials are recombinant viral vectors and synthetic nonviral vectors. Recombinant viral vectors take advantage of the evolutionarily optimized viral mechanisms to deliver genes, but they can be hard to specifically target in vivo and are also associated with serious side effects. Synthetic nonviral vectors are made out of highly biocompatible lipids or polymers, but they are much less efficient at delivering their genetic payload due to the lack of any active delivery mechanism. This mini review will introduce the current state of gene delivery in clinical trials, and discuss the specific challenges associated with each of these vectors. It will also highlight some specific gaps in knowledge that are limiting the advancement of this field and touch on the current areas of research being explored to overcome them.

The Ginkgo biloba Extract EGb 761 Modulates Proteasome Activity and Polyglutamine Protein Aggregation

The standardized Ginkgo biloba extract EGb 761 has well-described antioxidative activities and effects on different cytoprotective signaling pathways. Consequently, a potential use of EGb 761 in neurodegenerative diseases has been proposed. A common characteristic feature of a variety of such disorders is the pathologic formation of protein aggregates, suggesting a crucial role for protein homeostasis. In this study, we show that EGb 761 increased the catalytic activity of the proteasome and enhanced protein degradation in cultured cells. We further investigated this effect in a cellular model of Huntington's disease (HD) by employing cells expressing pathologic variants of a polyglutamine protein (polyQ protein). We show that EGb 761 affected these cells by (i) increasing proteasome activity and (ii) inducing a more efficient degradation of aggregation-prone proteins. These results demonstrate a novel activity of EGb 761 on protein aggregates by enhancing proteasomal protein degradation, suggesting a therapeutic use in neurodegenerative disorders with a disturbed protein homeostasis.