Baculovirus-mediated miRNA regulation to suppress hepatocellular carcinoma tumorigenicity and metastasis

Antigen Delivery Systems: Past, Present, and Future

The COVID-19 pandemic has increased demand for safe and effective vaccines. Research to develop vaccines against diseases including Middle East respiratory syndrome, Ebolavirus, human immunodeficiency virus, and various cancers would also contribute to global well-being. For successful vaccine development, the advancement of technologies such as antigen (Ag) screening, Ag delivery systems and adjuvants, and manufacturing processes is essential. Ag delivery systems are required not only to deliver a sufficient amount of Ag for vaccination, but also to enhance immune response. In addition, Ag types and their delivery systems determine the manufacturing processes of the vaccine product. Here, we analyze the characteristics of various Ag delivery systems: plasmids, viral vectors, bacterial vectors, nanoparticles, self-assembled particles, natural and artificial cells, and extracellular vesicles. This review provides insight into the current vaccine landscape and highlights promising avenues of research for the development and improvement of Ag delivery systems.

Molecular Targets and Signaling Pathways of microRNA-122 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading global causes of cancer mortality. MicroRNAs (miRNAs) are small interfering RNAs that alleviate the levels of protein expression by suppressing translation, inducing mRNA cleavage, and promoting mRNA degradation. miR-122 is the most abundant miRNA in the liver and is responsible for several liver-specific functions, including metabolism, cellular growth and differentiation, and hepatitis virus replication. Recent studies have shown that aberrant regulation of miR-122 is a key factor contributing to the development of HCC. In this review, the signaling pathways and the molecular targets of miR-122 involved in the progression of HCC have been summarized, and the importance of miR-122 in therapy has been discussed.

Anti-Hepatocellular Carcinoma Biomolecules: Molecular Targets Insights

This report explores the available curative molecules directed against hepatocellular carcinoma (HCC). Limited efficiency as well as other drawbacks of existing molecules led to the search for promising potential alternatives. Understanding of the cell signaling mechanisms propelling carcinogenesis and driven by cell proliferation, invasion, and angiogenesis can offer valuable information for the investigation of efficient treatment strategies. The complexity of the mechanisms behind carcinogenesis inspires researchers to explore the ability of various biomolecules to target specific pathways. Natural components occurring mainly in food and medicinal plants, are considered an essential resource for discovering new and promising therapeutic molecules. Novel biomolecules normally have an advantage in terms of biosafety. They are also widely diverse and often possess potent antioxidant, anti-inflammatory, and anti-cancer properties. Based on quantitative structure-activity relationship studies, biomolecules can be used as templates for chemical modifications that improve efficiency, safety, and bioavailability. In this review, we focus on anti-HCC biomolecules that have their molecular targets partially or completely characterized as well as having anti-cancer molecular mechanisms that are fairly described.

Contemporary Transposon Tools: A Review and Guide through Mechanisms and Applications of Sleeping Beauty, piggyBac and Tol2 for Genome Engineering

Transposons are mobile genetic elements evolved to execute highly efficient integration of their genes into the genomes of their host cells. These natural DNA transfer vehicles have been harnessed as experimental tools for stably introducing a wide variety of foreign DNA sequences, including selectable marker genes, reporters, shRNA expression cassettes, mutagenic gene trap cassettes, and therapeutic gene constructs into the genomes of target cells in a regulated and highly efficient manner. Given that transposon components are typically supplied as naked nucleic acids (DNA and RNA) or recombinant protein, their use is simple, safe, and economically competitive. Thus, transposons enable several avenues for genome manipulations in vertebrates, including transgenesis for the generation of transgenic cells in tissue culture comprising the generation of pluripotent stem cells, the production of germline-transgenic animals for basic and applied research, forward genetic screens for functional gene annotation in model species and therapy of genetic disorders in humans. This review describes the molecular mechanisms involved in transposition reactions of the three most widely used transposon systems currently available (Sleeping Beauty, piggyBac, and Tol2), and discusses the various parameters and considerations pertinent to their experimental use, highlighting the state-of-the-art in transposon technology in diverse genetic applications.

Doxifluridine-based pharmacosomes delivering miR-122 as tumor microenvironments-activated nanoplatforms for synergistic treatment of hepatocellular carcinoma

A novel kind of anti-cancer pharmacosome (named NPC-D) derived from Doxifluridine (5'-DFUR) was described, which could be activated by tumor microenvironments (TMEs). The NPC-D with H₂O₂-sensitive linker was dispersed well in water and simultaneously interacted with nucleic acids including plasmids encoding miR-122 (p122) and EpCAM-targeted aptamer (ap1) via charge interaction and hydrogen bonding. The integrated nanosystem (p122-ap1@NPC-D) was found to unleash by programmed TMEs (high level of H₂O₂ and low pH) to efficiently transfect miR-122 into MHCC-LM3 cells, followed by the releases of 5-FU. Besides, p122-ap1@NPC-D significantly countered the chemotherapy resistance and played a synergistic effect. These unique nanoparticles dramatically enhanced the anti-proliferation, and modulated the cellular apoptosis by the down-regulation of various signal pathways which imparted a bright application prospect in HCC treatment.

Effect of intramuscular baculovirus encoding mutant hypoxia-inducible factor 1-alpha on neovasculogenesis and ischemic muscle protection in rabbits with peripheral arterial disease

BACKGROUND AIMS

Peripheral arterial disease (PAD) is a progressive, disabling ailment for which no effective treatment exists. Gene therapy-mediated neovascularization has emerged as a potentially useful strategy. We tested the angiogenic and arteriogenic efficacy and safety of a baculovirus (BV) encoding mutant, oxygen-resistant hypoxia-inducible factor 1-alpha (mHIF-1α), in rabbits with PAD.

METHODS

After assessing the transfection efficiency of the BV.mHIF-1α vector and its tubulogenesis potential in vitro, we randomized rabbits with experimental PAD to receive 1 × 10⁹ copies of BV.mHIF-1α or BV.null (n = 6 per group) 7 days after surgery. Two weeks post-treatment, collateralization (digital angiography) and capillary and arteriolar densities (immunohistochemistry) were measured in the posterior limbs. Ischemic damage was evaluated in adductor and gastrocnemius muscle samples. Tracking of viral DNA in injected zones and remote tissues at different time points was performed in additional rabbits using a BV encoding GFP.

RESULTS

Angiographically visible collaterals were more numerous in BV.mHIF-1α-treated rabbits (8.12 ± 0.42 vs 6.13 ± 1.15 collaterals/cm², P < 0.05). The same occurred with arteriolar (27.9 ± 7.0 vs 15.3 ± 4.0 arterioles/mm²) and capillary (341.8 ± 109.9 vs 208.8 ± 87.7 capillaries/mm², P < 0.05) densities. BV.mHIF-1α-treated rabbits displayed less ischemic muscle damage than BV.null-treated animals. Viral DNA and GFP mRNA were detectable only at 3 and 7 days after injection in hind limbs. Neither the virus nor GFP mRNA was detected in remote tissues.

CONCLUSIONS

In rabbits with PAD, BV.mHIF-1α induced neovascularization and reduced ischemic damage, exhibiting a good safety profile at 14 days post-treatment. Complementary studies to evaluate its potential usefulness in the clinic are needed.

BCL-w: apoptotic and non-apoptotic role in health and disease

The BCL-2 family of proteins integrates signals that trigger either cell survival or apoptosis. The balance between pro-survival and pro-apoptotic proteins is important for tissue development and homeostasis, while impaired apoptosis contributes to several pathologies and can be a barrier against effective treatment. BCL-w is an anti-apoptotic protein that shares a sequence similarity with BCL-X_L, and exhibits a high conformational flexibility. BCL-w level is controlled by a number of signaling pathways, and the repertoire of transcriptional regulators largely depends on the cellular and developmental context. As only a few disease-relevant genetic alterations of BCL2L2 have been identified, increased levels of BCL-w might be a consequence of abnormal activation of signaling cascades involved in the regulation of BCL-w expression. In addition, BCL-w transcript is a target of a plethora of miRNAs. Besides its originally recognized pro-survival function during spermatogenesis, BCL-w has been envisaged in different types of normal and diseased cells as an anti-apoptotic protein. BCL-w contributes to survival of senescent and drug-resistant cells. Its non-apoptotic role in the promotion of cell migration and invasion has also been elucidated. Growing evidence indicates that a high BCL-w level can be therapeutically relevant in neurodegenerative disorders, neuron dysfunctions and after small intestinal resection, whereas BCL-w inhibition can be beneficial for cancer patients. Although several drugs and natural compounds can bi-directionally affect BCL-w level, agents that selectively target BCL-w are not yet available. This review discusses current knowledge on the role of BCL-w in health, non-cancerous diseases and cancer.

Validation of miR-20a as a Tumor Suppressor Gene in Liver Carcinoma Using Hepatocyte-Specific Hyperactive piggyBac Transposons

We established a semi-high-throughput in vivo screening platform using hyperactive piggyBac (hyPB) transposons (designated as PB-miR) to identify microRNAs (miRs) that inhibit hepatocellular carcinoma (HCC) development in vivo, following miR overexpression in hepatocytes. PB-miRs encoding six different miRs from the miR-17-92 cluster and nine miRs from outside this cluster were transfected into mouse livers that were chemically induced to develop HCC. In this slow-onset HCC model, miR-20a significantly inhibited HCC. Next, we developed a more aggressive HCC model by overexpression of oncogenic Harvey rat sarcoma viral oncogene homolog (HRASG12V) and c-MYC oncogenes that accelerated HCC development after only 6 weeks. The tumor suppressor effect of miR-20a could be demonstrated even in this rapid-onset HRASG12V/c-MYC HCC model, consistent with significantly prolonged survival and decreased HCC tumor burden. Comprehensive RNA expression profiling of 95 selected genes typically associated with HCC development revealed differentially expressed genes and functional pathways that were associated with miR-20a-mediated HCC suppression. To our knowledge, this is the first study establishing a direct causal relationship between miR-20a overexpression and liver cancer inhibition in vivo. Moreover, these results demonstrate that hepatocyte-specific hyPB transposons are an efficient platform to screen and identify miRs that affect overall survival and HCC tumor regression.

Long Non-Coding RNA NEAT1 Promoted Hepatocellular Carcinoma Cell Proliferation and Reduced Apoptosis Through the Regulation of Let-7b-IGF-1R Axis

Background and aim

Long non-coding RNA nuclear-enriched abundant transcript 1 (NEAT1) is abnormally expressed in various human malignancies, including hepatocellular carcinoma (HCC). Let-7b is a miRNA with the effect of a tumor suppressor gene, and its expression level in various tumor tissues is lower than that in normal tissues. Studies have found that IGF-1R can be abnormally activated in the process of hepatocyte deterioration, and the expression level of IGF-1R in HCC is significantly up-regulated. The aim of this study was to investigate the functional mechanism of NEAT1/let-7b-IGF-1R axis in HCC.

Methods

The expressions of NEAT1 and microRNA (miR)-let-7b in HCC tissues and cell lines were quantified by quantitative real-time PCR (qRT-PCR). The effect of NEAT1 on tumor growth was observed in a mice model of transplanted hepatoma. The effects of down-regulation or up-regulation of NEAT1 expression in HCC cell lines were analysed from the perspectives of cell viability and apoptosis. The binding sites of NEAT1 and miR-let-7b were predicted by biological software. The expression of the miR-let-7b target molecules IGF-1R was detected by Western blotting.

Results

The results showed that the expressions of NEAT1 were significantly increased, while the expressions of miR-let-7b were decreased in the HCC tissues and cell lines. Additionally, it was found that the expressions of NEAT1 and miR-let-7b showed a negative correlation in HCC tissues. The mouse model experiments confirmed that the interference with NEAT1 expression inhibited the tumor growth. Meanwhile, the cell viability of HepG2/Huh7 cell lines was significantly decreased via the downregulation of NEAT1, whereas the corresponding rates of apoptosis were significantly increased. It was further proven that there was a certain negative regulatory mechanism between NEAT1 and miR-1et-7b, which was related to the expression of IGF-1R.

Conclusion

The over-expression of NEAT1 could promote the proliferation of HCC cells by inhibiting the expression of the miR-let-7b regulated by IGF-1R.

Stage-dependent involvement of ADAM10 and its significance in epileptic seizures

The prevalence of epileptic seizures in Alzheimer's disease (AD) has attracted an increasing amount of attention in recent years, and many cohort studies have found several risk factors associated with the genesis of seizures in AD. Among these factors, young age and severe dementia are seemingly contradictory and independent risk factors, indicating that the pathogenesis of epileptic seizures is, to a certain extent, stage‐dependent. A disintegrin and metalloproteinase domain‐containing protein 10 (ADAM10) is a crucial α‐secretase responsible for ectodomain shedding of its substrates; thus, the function of this protein depends on the biological effects of its substrates. Intriguingly, transgenic models have demonstrated ADAM10 to be associated with epilepsy. Based on the biological effects of its substrates, the potential pathogenic roles of ADAM10 in epileptic seizures can be classified into amyloidogenic processes in the ageing stage and cortical dysplasia in the developmental stage. Therefore, ADAM10 is reviewed here as a stage‐dependent modulator in the pathogenesis of epilepsy. Current data regarding ADAM10 in epileptic seizures were collected and reviewed for potential pathogenic roles (ie amyloidogenic processes and cortical dysplasia) and regulatory mechanisms (ie transcriptional and posttranscriptional regulation). These findings are then discussed in terms of the significance of the stage‐dependent functions of ADAM10 in epilepsy. Several potential targets for seizure control, such as candidate transcription factors and microRNAs that regulate ADAM10, as well as potential genetic screening tools for the early recognition of cortical dysplasia, have been suggested but must be studied in more detail.

Synthetic switch-based baculovirus for transgene expression control and selective killing of hepatocellular carcinoma cells

Baculovirus (BV) holds promise as a vector for anticancer gene delivery to combat the most common liver cancer-hepatocellular carcinoma (HCC). However, in vivo BV administration inevitably results in BV entry into non-HCC normal cells, leaky anticancer gene expression and possible toxicity. To improve the safety, we employed synthetic biology to engineer BV for transgene expression regulation. We first uncovered that miR-196a and miR-126 are exclusively expressed in HCC and normal cells, respectively, which allowed us to engineer a sensor based on distinct miRNA expression signature. We next assembled a synthetic switch by coupling the miRNA sensor and RNA binding protein L7Ae for translational repression, and incorporated the entire device into a single BV. The recombinant BV efficiently entered HCC and normal cells and enabled cis-acting transgene expression control, by turning OFF transgene expression in normal cells while switching ON transgene expression in HCC cells. Using pro-apoptotic hBax as the transgene, the switch-based BV selectively killed HCC cells in separate culture and mixed culture of HCC and normal cells. These data demonstrate the potential of synthetic switch-based BV to distinguish HCC and non-HCC normal cells for selective transgene expression control and killing of HCC cells.

Therapeutic effects of serum extracellular vesicles in liver fibrosis

The lack of approved therapies for hepatic fibrosis seriously limits medical management of patients with chronic liver disease. Since extracellular vesicles (EVs) function as conduits for intercellular molecular transfer, we investigated if EVs from healthy individuals have anti-fibrotic properties. Hepatic fibrogenesis or fibrosis in carbon tetrachloride (CCl₄)- or thioacetic acid-induced liver injury models in male or female mice were suppressed by serum EVs from normal mice (EVN) but not from fibrotic mice (EVF). CCl₄-treated mice undergoing EVN therapy also exhibited reduced levels of hepatocyte death, inflammatory infiltration, circulating AST/ALT levels and hepatic or circulating pro-inflammatory cytokines. Hepatic histology, liver function tests or circulating proinflammatory cytokine levels were unaltered in control mice receiving EVN. As determined using PKH26-labelled EVN, principal target cells included hepatic stellate cells (HSC; a normally quiescent fibroblastic cell that undergoes injury-induced activation and produces fibrosis during chronic injury) or hepatocytes which showed increased EVN binding after, respectively, activation or exposure to CCl₄. In vitro, EVN decreased proliferation and fibrosis-associated molecule expression in activated HSC, while reversing the inhibitory effects of CCl₄ or ethanol on hepatocyte proliferation. In mice, microRNA-34c, -151-3p, -483-5p, -532-5p and -687 were more highly expressed in EVN than EVF and mimics of these microRNAs (miRs) individually suppressed fibrogenic gene expression in activated HSC. A role for these miRs in contributing to EVN actions was shown by the ability of their corresponding antagomirs to individually and/or collectively block the therapeutic effects of EVN on activated HSC or injured hepatocytes. Similarly, the activated phenotype of human LX-2 HSC was attenuated by serum EVs from healthy human subjects and contained higher miR-34c, -151-3p, -483-5p or -532-5p than EVs from hepatic fibrosis patients. In conclusion, serum EVs from normal healthy individuals are inherently anti-fibrogenic and anti-fibrotic, and contain microRNAs that have therapeutic actions in activated HSC or injured hepatocytes.

Abbreviations: ALT: alanine aminotransferase; AST: aspartate aminotransferase; CCl₄: carbon tetrachloride; CCN2: connective tissue growth factor; E: eosin; EGFP: enhanced green fluorescent protein; EVs: extracellular vesicles; EVF: serum EVs from mice with experimental hepatic fibrosis; EVN: serum EVs from normal mice; H: hematoxylin; HSC: hepatic stellate cell; IHC: immunohistochemistry; IL: interleukin; MCP-1: monocyte chemotactic protein-1; miR: microRNA; mRNA: messenger RNA; NTA: nanoparticle tracking analysis; PCNA: proliferating cell nuclear antigen; qRT-PCR: quantitative real-time polymerase chain reaction; SDS-PAGE: sodium dodecyl sulphate – polyacrylamide gel electrophoresis; αSMA: alpha smooth muscle actin; TAA: thioacetic acid; TG: transgenic; TGF-β: transforming growth factor beta; TEM: transmission electron microscopy; TNFα: tumour necrosis factor alpha.

miR-223-3p Inhibits Human Osteosarcoma Metastasis and Progression by Directly Targeting CDH6

Cadherin-6 (CDH6) is aberrantly expressed in cancer and closely associated with tumor progression. However, the functions of CDH6 in human osteosarcoma and the molecular mechanisms underlying CDH6 in osteosarcoma oncogenesis remain poorly understood. In this work, we assessed the role of CDH6 in human osteosarcoma and identified that the expression of CDH6 was closely related with the overall survival and poor prognosis of osteosarcoma patients. MicroRNAs (miRNAs) have been implicated as important epigenetic regulators during the progression of osteosarcoma. Using dual-luciferase reporter assays, we showed that miR-223-3p suppresses CDH6 expression by directly binding to the 3' UTR of CDH6. miR-223-3p overexpression significantly inhibited cell invasion, migration, growth, and proliferation by suppressing the CDH6 expression in vivo and in vitro. Besides, CDH6 overexpression in the miR-223-3p-transfected osteosarcoma cells effectively rescued the inhibition of cell invasion, migration, growth, and proliferation mediated by miR-223-3p. Additionally, Kaplan-Meier analysis suggests that the expression of miR-223-3p predicts favorable clinical outcomes for osteosarcoma patients. Moreover, the expression of miR-223-3p was downregulated in osteosarcoma patients and was negatively associated with the expression of CDH6. Collectively, these data highlight that miR-223-3p/CDH6 axis is an important novel pleiotropic regulator and could early predict the metastatic potential in human osteosarcoma treatments.

Inflammatory-Related P62 Triggers Malignant Transformation of Mesenchymal Stem Cells through the Cascade of CUDR-CTCF-IGFII-RAS Signaling

Inflammatory and autophagy-related gene P62 is highly expressed in most human tumor tissues. Herein, we demonstrate that P62 promotes human mesenchymal stem cells' malignant transformation via the cascade of P62-tumor necrosis factor alpha (TNF-α)-CUDR-CTCF-insulin growth factor II (IGFII)-H-Ras signaling. Mechanistically, we reveal P62 enhances IGFII transcriptional activity through forming IGFII promoter-enhancer chromatin loop and increasing METTL3 occupancy on IGFII 3' UTR and enhances H-Ras overexpression by harboring inflammation-related factors, e.g., TNFR1, CLYD, EGR1, NFκB, TLR4, and PPARγ. Furthermore, the P62 cooperates with TNF-α to promote malignant transformation of mesenchymal stem cells. These findings, for the first time, provide insight into the positive role that P62 plays in malignant transformation of mesenchymal stem cells and reveal a novel link between P62 and the inflammation factors in mesenchymal stem cells.

MiR-122 modification enhances the therapeutic efficacy of adipose tissue-derived mesenchymal stem cells against liver fibrosis

Mesenchymal stem cell (MSC) transplantation alone may be insufficient for treatment of liver fibrosis because of complicated histopathological changes in the liver. Given that miR‐122 plays an essential role in liver fibrosis by negatively regulating the proliferation and transactivation of hepatic stellate cells (HSCs), this study investigated whether miR‐122 modification can improve the therapeutic efficacy of adipose tissue‐derived MSCs in treating liver fibrosis. MiR‐122‐modified AMSCs (AMSC‐122) were constructed through lentivirus‐mediated transfer of pre‐miR‐122. MiR‐122‐modified AMSCs expressed high level of miR‐122, while they retained their phenotype and differentiation potential as naïve AMSCs. AMSC‐122 more effectively suppressed the proliferation of and collagen maturation in HSCs than scramble miRNA‐modified AMSCs. In addition, AMSC‐derived exosomes mediated the miR‐122 communication between AMSCs and HSCs, further affecting the expression levels of miR‐122 target genes, such as insulin‐like growth factor receptor 1 (IGF1R), Cyclin G(1) (CCNG1) and prolyl‐4‐hydroxylase α1 (P4HA1), which are involved in proliferation of and collagen maturation in HSCs. Moreover, miR‐122 modification enhanced the therapeutic efficacy of AMSCs in the treatment of carbon tetrachloride (CCl₄)‐induced liver fibrosis by suppressing the activation of HSCs and alleviating collagen deposition. Results demonstrate that miR‐122 modification improves the therapeutic efficacy of AMSCs through exosome‐mediated miR‐122 communication; thus, miR‐122 modification is a new potential strategy for treatment of liver fibrosis.

Efficacy and safety of the glycine transporter type-1 inhibitor AMG 747 for the treatment of negative symptoms associated with schizophrenia

OBJECTIVE

To determine the safety and efficacy of AMG 747, an oral inhibitor of glycine transporter type-1 (GlyT1), as an add-on to antipsychotic therapy in clinically stable people with schizophrenia with enduring negative symptoms.

METHOD

Analysis of pooled data from two phase 2 studies. Adults diagnosed with schizophrenia stabilized on antipsychotic medication randomized (2:2:2:3) to orally receive daily AMG 747 (5mg, 15mg, or 40mg) or placebo. Primary endpoint was Negative Symptom Assessment (NSA)-16 total score change from baseline to week 12.

RESULTS

Studies were terminated early after a report of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN) in one participant (40-mg AMG 747). At termination, 232 participants had enrolled and 153 completed 12weeks of treatment. At week 12, change from baseline NSA-16 total score showed no differences between groups. Mean decrease in Positive and Negative Syndrome Scale (PANSS) Negative Symptom Factor Score (NSFS) and NSA-16 global score were greater with 15-mg AMG 747 than placebo (p<0.05). Changes in PANSS-Positive Symptom Factor Scale were not significantly different for any group. Changes in patient-reported outcomes (Sheehan Disability Scale and Quality of Life Enjoyment and Satisfaction Questionnaire) showed trends consistent with greater efficacy of 15-mg AMG 747 compared with placebo (p≤0.1). Adverse event rates were similar among all groups, with no clear differences observed.

CONCLUSIONS

Significant treatment effects of 15-mg AMG 747, but not higher or lower doses, were observed on secondary endpoints but not on the primary outcome. These results replicate previous reports of an inverted-U dose response curve and suggest further evaluation of GlyT1 inhibitors in schizophrenia negative symptoms is warranted.

TRIAL REGISTRATION

Clinicaltrials.govNCT01568216 (https://clinicaltrials.gov/ct2/show/NCT01568216) and NCT01568229 (https://clinicaltrials.gov/ct2/show/NCT01568229?term=NCT01568229&rank=1); EudraCT number 2011-004844-23 and 2011-004845-42.

Role of Rho-specific guanine nucleotide dissociation inhibitor α regulation in cell migration

Cell migration is a vital process for many physiological and pathological events, and Rho GTPases have been confirmed as key factors in its regulation. The most studied negative regulator of Rho GTPases, Rho-specific guanine nucleotide dissociation inhibitor α (RhoGDIα), mediates cell migration through altering the overall expression and spatiotemporal activation of Rho GTPases. The RhoGDIα-Rho GTPases dissociation can be mediated by signal pathways targeting RhoGDIα directly. This review summarizes the research about the regulation of RhoGDIα during cell migration, which can be in a Rho GTPases association independent manner. Non-kinase proteins regulation, phosphorylation, SUMOylation and extracellular environmental factors are classified to discuss their direct signal regulations on RhoGDIα, which provide varied signal pathways for selective activation of Rho GTPases in cell migration.

Improved calvarial bone repair by hASCs engineered with Cre/loxP-based baculovirus conferring prolonged BMP-2 and MiR-148b co-expression

Repairing large calvarial bone defects remains a challenging task. Previously, it was discovered that that miR-148b, when acting in concert with bone morphogenetic protein 2 (BMP-2), enhanced the osteogenesis of human adipose-derived stem cells (hASCs) and improved calvarial bone healing in nude mice. However, the molecular target of miR-148b remained elusive. Here it is revealed that miR-148b directly targets NOG, whose gene product (noggin) is an antagonist to BMPs and negatively regulates BMP-induced osteogenic differentiation and bone formation. A new Cre/loxP-based baculovirus system was employed to drive prolonged BMP-2 and miR-148b overexpression in hASCs, wherein the BMP-2 overexpression induced noggin expression but the concurrent miR-148b expression downregulated noggin, thus relieving the negative regulatory loop and ameliorating hASC osteogenesis without hindering hASC proliferation or triggering appreciable cytotoxicity. Implantation of the engineered hASCs coexpressing BMP-2 and miR-148b into nude mice enabled substantial repair of critical-size calvarial bone defects (4 mm diameter) at 12 weeks post-transplantation, filling 83% of the defect area, 75% of bone volume and restoring the bone density to 89% of the original bone density. Such superior healing effects indicate the potential of the Cre/loxP-based baculovirus-mediated BMP-2/miR-148b expression for calvarial bone repair. Copyright © 2016 John Wiley & Sons, Ltd.

miR675 upregulates long noncoding RNA H19 through activating EGR1 in human liver cancer

microRNAs (miRNAs) are short non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miR675, embedded in H19's first exon, had been linked to the development of human cancers. Herein, we demonstrate miR675 overexpression promotes and silencing miR675 attenuated liver cancer cell growth in vitro and in vivo. Mechanistically, miR675 inhibits the heterochromatin1 isoform HP1α expression in human liver cancer cells which causes a dramatically decrease of the total histone H3 lysine 9 trimethylation (H3K9me3) , histone H3 lysine 27 trimethylation (H3K27me3) and a increase of histone H3 lysine 27 acetylation(H3K27Ac).Notably, a significant reduction of the H3K9me3 and H3K27me3 and the increment of H3K27Ac occupancy on the promoter region of EGR1 triggers EGR1 transcription, translation, sumoylation and activation which upregulates lincRNA H19. Strikingly, H19 may induce and activate tumor-specific pyruvate kinase M2 (PKM2) which is essential for the Warburg effect in its dimer and for gene expression in its teramer during tumorigenesis. Our results imply that miR675 is involved in the epigenetic regulation of H3K9me3, H3k27me3 and H3K27Ac for gene expression and function during hepatocarcinogenesis (e.g.C-myc,Pim1,Ras,CyclinD1,RB1).These findings sheds light on the significance of miR675-HP1α-EGR1-H19-PKM2 cascade signaling pathway in liver cancer.

Topoisomerase II Inhibitors Can Enhance Baculovirus-Mediated Gene Expression in Mammalian Cells through the DNA Damage Response

BacMam is an insect-derived recombinant baculovirus that can deliver genes into mammalian cells. BacMam vectors carrying target genes are able to enter a variety of cell lines by endocytosis, but the level of expression of the transgene depends on the cell line and the state of the transduced cells. In this study, we demonstrated that the DNA damage response (DDR) could act as an alternative pathway to boost the transgene(s) expression by BacMam and be comparable to the inhibitors of histone deacetylase. Topoisomerase II (Top II) inhibitor-induced DDR can enhance the CMV-IE/enhancer mediated gene expression up to 12-fold in BacMam-transduced U-2OS cells. The combination of a Top II inhibitor, VM-26, can also augment the killing efficiency of a p53-expressing BacMam vector in U-2OS osteosarcoma cells. These results open a new avenue to facilitate the application of BacMam for gene delivery and therapy.

Elevated MTSS1 expression associated with metastasis and poor prognosis of residual hepatitis B-related hepatocellular carcinoma

Background

Hepatectomy generally offers the best chance of long-term survival for patients with hepatocellular carcinoma (HCC). Many studies have shown that hepatectomy accelerates tumor metastasis, but the mechanism remains unclear.

Methods

An orthotopic nude mice model with palliative HCC hepatectomy was performed in this study. Metastasis-related genes in tumor following resection were screened; HCC invasion, metastasis, and some molecular alterations were examined in vivo and in vitro. Clinical significance of key gene mRNA expression was also analyzed.

Results

Metastasis suppressor 1 (MTSS1) located in the central position of gene function net of residual HCC. MTSS1 was up-regulated in residual tumor after palliative resection. In hepatitis B-related HCC patients undergone palliative hepatectomy, those with higher MTSS1 mRNA expression accompanied by activation of matrix metalloproteinase 2 (MMP2) in residual HCC, had earlier residual HCC detection after hepatectomy and poorer survival when compared to those with lower MTSS1. In different cell lines, the levels of MTSS1 mRNA increased in parallel with metastatic potential. MTSS1 down regulation via siRNA decreased MMP2 activity, reduced invasive potentials of HCC by 28.9 % in vitro, and averted the deteriorated lung metastatic extent in vivo.

Conclusions

The poor prognosis of hepatitis B-related HCC patients following palliative hepatectomy associates with elevated MTSS1 mRNA expression; therefore, MTSS1 may provide a new research field for HCC diagnosis and treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0361-8) contains supplementary material, which is available to authorized users.

miR-122 inhibits cancer cell malignancy by targeting PKM2 in gallbladder carcinoma

Gallbladder cancer (GBC) is one of the lethal diseases of digestive system. Increasing evidence prompt that microRNAs (miRs) might provide a novel therapeutical target for malignant disease. The antitumor effect of miR-122 to GBC is worth to be investigated. miR-122 expression level in GBC tissue sample and cell lines were assayed by qRT-PCR. miR-122 mimics were transfected for upregulation of miR-122 expression. Cell function was assayed by CCK8, flow cytometry, wound healing assay, migration assay, and invasion assay. The target genes of miR-122 were predicated by TargetScan online program and verified by western blot and luciferase report gene assay. miR-122 was decreased in GBC tissue and cell lines. The exogenous introduction of miR-122 exhibits multiple antitumor effect in GBC cell proliferation, invasion, and metastasis. Further studies revealed that the PKM2 was a regulative target of miR-122 in GBC cell. miR-122 also inhibits TGF-β-induced epithelium mesenchymal transformation of GBC cell by downregulating PKM2 expression. These findings suggest that miR-122 plays an important role in tumorigenesis of GBC through interfering PKM2, highlighting its usefulness as a potential therapeutic agent in GBC.

Enhanced angiogenesis in ischemic skeletal muscle after transplantation of cell sheets from baculovirus-transduced adipose-derived stromal cells expressing VEGF165

Introduction

Cell therapy using adipose-derived stromal cells (ADSC) is an intensively developing approach to promote angiogenesis and regeneration. Administration technique is crucial and among others minimal constructs - cell sheets (CS) have certain advantages. Delivery of CS allows transplantation of cells along with matrix proteins to facilitate engraftment. Cells’ therapeutic potential can be also increased by expression of proangiogenic factors by viral transduction. In this work we report on therapeutic efficacy of CS from mouse ADSC transduced to express human vascular endothelial growth factor 165 a/a isoform (VEGF165), which showed potency to restore perfusion and protect tissue in a model of limb ischemia.

Methods

Mouse ADSC (mADSC) isolated from C57 male mice were expanded for CS formation (10⁶cells per CS). Constructs were transduced to express human VEGF165 by baculoviral (BV) system. CS were transplanted subcutaneously to mice with surgically induced limb ischemia and followed by laser Doppler perfusion measurements. At endpoint animals were sacrificed and skeletal muscle was evaluated for necrosis and vessel density; CS with underlying muscle was stained for apoptosis, proliferation, monocytes and blood vessels.

Results

Using BV system and sodium butyrate treatment we expressed human VEGF165 in mADSC (production of VEGF165 reached ≈ 25-27 ng/ml/10⁵ cells) and optimized conditions to ensure cells’ viability after transduction. Implantation of mock-transduced CS resulted in significant improvement of limb perfusion, increased capillary density and necrosis reduction at 2 weeks post-surgery compared to untreated animals. Additional improvement of blood flow and angiogenesis was observed after transplantation of VEGF165-expressing CS indicating enhanced therapeutic potential of genetically modified constructs. Moreover, we found delivery of mADSC as CS to be superior to equivalent dose of suspended cells in terms of perfusion and angiogenesis. Histology analysis of extracted CS detected limited proliferation and approximately 10 % prevalence of apoptosis in transplanted mADSC. Significant vascularization of CS and infiltration by monocytes were found in both – BV-transduced and control CS indicating graft and host interaction after transplantation.

Conclusions

Delivery of ADSC by subcutaneous transplantation of CS is effective for stimulation of angiogenesis and tissue protection in limb ischemia with a potential for efficacy improvement by BV transduction to express VEGF165.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0199-6) contains supplementary material, which is available to authorized users.

Cartilage tissue engineering: recent advances and perspectives from gene regulation/therapy

Diseases in articular cartilages affect millions of people. Despite the relatively simple biochemical and cellular composition of articular cartilages, the self-repair ability of cartilage is limited. Successful cartilage tissue engineering requires intricately coordinated interactions between matrerials, cells, biological factors, and phycial/mechanical factors, and still faces a multitude of challenges. This article presents an overview of the cartilage biology, current treatments, recent advances in the materials, biological factors, and cells used in cartilage tissue engineering/regeneration, with strong emphasis on the perspectives of gene regulation (e.g., microRNA) and gene therapy.

Baculovirus-mediated gene delivery and RNAi applications

Baculoviruses are widely encountered in nature and a great deal of data is available about their safety and biology. Recently, these versatile, insect-specific viruses have demonstrated their usefulness in various biotechnological applications including protein production and gene transfer. Multiple in vitro and in vivo studies exist and support their use as gene delivery vehicles in vertebrate cells. Recently, baculoviruses have also demonstrated high potential in RNAi applications in which several advantages of the virus make it a promising tool for RNA gene transfer with high safety and wide tropism.

Sponging of cellular proteins by viral RNAs

Viral RNAs accumulate to high levels during infection and interact with a variety of cellular factors including miRNAs and RNA-binding proteins. Although many of these interactions exist to directly modulate replication, translation and decay of viral transcripts, evidence is emerging that abundant viral RNAs may in certain cases serve as a sponge to sequester host non-coding RNAs and proteins. By effectively reducing the ability of cellular RNA binding proteins to regulate host cell gene expression, viral RNAs can alter the response to infection and favor viral replication. This review focuses on the potential contribution that sequestration of cellular proteins by viral RNAs makes to viral replication and cytopathology.