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Self-replicating RNA (repRNA) derived from venezuelan equine encephalitis (VEE) virus is a promising platform for gene therapy and confers prolonged gene expression due to its self-replicating capability, but repRNA suffers from a suboptimal transgene expression level due to its induction of intracellular innate response which may result in inhibition of translation. To improve transgene expression of repRNA, we introduced point mutations in the non-structural protein 1-4 (nsP1-4) coding region of VEE replicon vectors. As a proof of concept, inflammatory cytokines served as genes of interest and were cloned in either their wild type or several mutant replicon vectors, followed by transfection in mammalian cells. Our data show that VEE replicons bearing nsP1GGAC-nsP2T and nsP1GGAC-nsP2AT mutations in the nsP1-4 coding region significantly enhance transgene expression. Thus, the newly discovered mutant VEE replicon vectors could serve as promising gene expression platforms to advance VEE-derived repRNA-based gene therapies.

To study the mechanism of the anti-tumor effect of Morinda citrifolia (noni). The influences of noni juice on cell proliferation, apoptosis, invasion, migration and the activity of AKT/nuclear factor- κ B (NF- κ B) signaling pathway in A549 human lung cancer cells were detected by MTT, cell counting kit-8, colony formation, Annexin V/PI double labeling, transwell, scratch test and immunoblotting assay, respectively. A549 cells were inoculated into the right axilla of nude mice, followed by noni juice treatment. The body weight of the nude mice was weighed, and the tumor volume and weight were measured. Cell proliferation and expression of apoptosis-related proteins were measured by immunohistochemistry, and the activity of NF- κ B signaling pathway was measured by immunoblotting. The in vitro studies showed that noni juice inhibited the A549 cells proliferation, migration and invasion. Noni juice also promoted cells apoptosis in A549 cells. Immunoblotting assay showed that the phosphorylation level of AKT, p50, and STAT3 proteins was inhibited to different extents after noni juice treatment. The in vivo studies showed that noni juice effectively suppressed tumor formation of A549 cells in nude mice. Noni juice treatment inhibited the expression of Ki67, PCNA, and Bcl-2 protein in the tumor; while promoted the expression of caspase-3 protein. Additionally, we also found that noni juice treatment could restrain the activity of AKT/NF- κ B signaling pathway in the tumor tissue. Noni juice inhibited the proliferation of A549 lung cancer cells, induced apoptosis, and inhibited cell invasion and migration via regulating AKT/NF- κ B signaling pathway.

The BCR/ABL fusion gene and its downstream signaling pathways such as Ras/Raf/MAPK, JAK/STAT3, and PI3K/AKT pathways play important roles in malignant transformation of leukemia, especially chronic myelogenous leukemia (CML). Our previous study showed that matrine, an alkaloid extracted from a Chinese herb radix sophorae, significantly inhibited the proliferation of human CML K562cells, induced cell cycle arrest in G0/G1, and promoted cell apoptosis. In the present study, we investigated the molecular mechanism of matrine in the growth inhibition of leukemia cells using K562 and HL-60 cell lines. RT-PCR and Western blot assay demonstrated that the expression of BCR/ABL in K562 and HL-60 cells was significantly inhibited by matrine treatment. Phosphorylation of MEK1, ERK1/2, and their upstream adaptor molecules Shc and SHP2 were significantly downregulated. The protein and mRNA expression of components of the ERK/MAPK signal pathway, and Bcl-xL, Cyclin D1, and c-Myc, were dramatically reduced. Conversely, the expression of p27, a negative regulator of cell cycle progression, increased after matrine treatment. These results indicated that the inhibition of ERK/MAPK and BCR/ABL signaling pathway was associated with matrine’s suppressive effects on the growth of K562 and HL-60 cells. In in vivo study, matrine significantly decreased the mortality rate of tumor-baring mice and suggested that matrine could exert its anti-leukemia effect in vivo.

For a long time, there has been global concern over the environment and energy problems. Recently, the problems, which have brought about serious effect on the global living condition, have been in the “spotlight” and given impetus to the universal’s efforts to head for the same direction: stem the worst warming and strive for the renewable energy source. Hydrogen peroxide (H2O2) is undoubtedly a good choice, which holds the promise as a clean, efficient, safe and transferrable energy carrier. Octahedral coordination polymer, Cd3(C3N3S3)2, was found to be a robust photocatalyst for H2O2 generation under visible light irradiation. To further improve the H2O2 generation efficiency, adhering the octahedron to reduced graphene (rGO) was applied as the strategy herein. The study shows that by adhering Cd3(C3N3S3)2 to rGO, the formation of H2O2 is 2.5-fold enhanced and its deformation is concurrently suppressed. This work not only demonstrates the effectiveness of adhering Cd3(C3N3S3)2 polymer to rGO for the improvement of the polymer’s photocatalytic performance, but also proposes a general way for the fabrication of graphene/coordination compound hybrids for maximizing their synergy.

The tumor suppressor Spred2 (Sprouty-related EVH1 domain-2) induces cell death in a variety of cancers. However, the underlying mechanism remains to be elucidated. Here we show that Spred2 induces caspase-independent but autophagy-dependent cell death in human cervical carcinoma HeLa and lung cancer A549 cells. We demonstrate that ectopic Spred2 increased both the conversion of microtubule-associated protein 1 light chain 3 (LC3), GFP-LC3 puncta formation and p62/SQSTM1 degradation in A549 and HeLa cells. Conversely, knockdown of Spred2 in tumor cells inhibited upregulation of autophagosome maturation induced by the autophagy inducer Rapamycin, which could be reversed by the rescue Spred2. These data suggest that Spred2 promotes autophagy in tumor cells. Mechanistically, Spred2 co-localized and interacted with LC3 via the LC3-interacting region (LIR) motifs in its SPR domain. Mutations in the LIR motifs or deletion of the SPR domain impaired Spred2-mediated autophagosome maturation and tumor cell death, indicating that functional LIR is required for Spred2 to trigger tumor cell death. Additionally, Spred2 interacted and co-localized with p62/SQSTM1 through its SPR domain. Furthermore, the co-localization of Spred2, p62 and LAMP2 in HeLa cells indicates that p62 may be involved in Spred2-mediated autophagosome maturation. Inhibition of autophagy using the lysosomal inhibitor chloroquine, reduced Spred2-mediated HeLa cell death. Silencing the expression of autophagy-related genes ATG5, LC3 or p62 in HeLa and A549 cells gave similar results, suggesting that autophagy is required for Spred2-induced tumor cell death. Collectively, these data indicate that Spred2 induces tumor cell death in an autophagy-dependent manner.

Background Aberrant activation of β-catenin and Yes-associated protein (YAP) signaling pathways has been associated with hepatocellular carcinoma (HCC) progression. The LIM domain protein Ajuba regulates β-catenin and YAP signaling and is implicated in tumorigenesis. However, roles and mechanism of Ajuba expression in HCC cells remain unclear. The E3 ligase Hakai has been shown to interact with other Ajuba family members and whether Hakai interacts and regulates Ajuba is unknown. Methods HCC cell lines stably depleted of Ajuba or Hakai were established using lentiviruses expressing shRNAs against Ajuba or Hakai. The effects of Ajuba on HCC cells were determined by a number of cell-based analyses including anchorage-independent growth, three dimension cultures and trans-well invasion assay. In vivo tumor growth was determined in a xenograft model and Ajuba expression in tumor sections was examined by immunohistochemistry. Co-immunoprecipitation, confocal microscopy and immunoblot assay were used to examine the expression and interaction between Ajuba and Hakai. Results Depletion of Ajuba in HCC cells significantly enhanced anchorage-independent growth, invasion, the formation of spheroids and tumor growth in a xenograft model, suggesting a tumor suppressor function for Ajuba in HCC. Mechanistically, Ajuba depletion triggered E-cadherin loss and β-catenin translocation with increased Cyclin D1 levels. In addition, depletion of Ajuba upregulated the levels of YAP and its target gene CYR61. Furthermore, siRNA-mediated knockdown of either β-catenin or YAP attenuated the pro-tumor effects by Ajuba depletion on HCC cells. Notably, Ajuba stability in HCC cells was regulated by Hakai, an E3 ligase for E-cadherin. Hakai interacted with Ajuba via its HYB domain and induced Ajuba neddylation, which was antagonized by the neddylation inhibitor, MLN4924, but not MG132. We further show that overexpression of Hakai in HCC cells markedly increased anchorage-independent growth, spheroid-formation ability and tumor growth in xenografts whereas Hakai depletion resulted in these opposite effects, indicating an oncogenic role for Hakai in HCC. Hakai also induced β-catenin translocation with increased levels of Cyclin D1. Conclusions Our data suggest a role for Ajuba and Hakai in HCC, and uncover the mechanism underlying the regulation of Ajuba stability. Electronic supplementary material The online version of this article (10.1186/s13046-018-0806-3) contains supplementary material, which is available to authorized users.

Acquired resistance to first-line chemotherapeutics, including paclitaxel (PTX), is a primary factor contributing to chemotherapy failure in non-small cell lung cancer (NSCLC) patients. Previous studies have identified that targeting NEDD8-activating enzyme (NAE) with MLN4924 effectively overcomes platinum resistance in preclinical models of ovarian cancer. However, the underlying mechanisms are yet to be fully elucidated. The present study demonstrates that the inhibition of the neddylation pathway with MLN4924 an NAE inhibitor inhibited protein neddylation, inactivated cullin-RING E3 ligase and exhibited a potent antiproliferative effect on PTX-resistant A549 and H460 cells (A549/PTX and H460/PTX). The application of MLN4924 promotes apoptosis and DNA damage in A549/PTX and H460/PTX cells. Additionally, MLN4924 abrogated the 3-dimensional growth potential of these cells and inhibited the formation of the A549/PTX and H460/PTX spheroids. Notably, combining MLN4924 with PTX did not exhibit synergy in PTX-resistant NSCLC cells. Taken together, the results of the current study suggest that MLN4924 may be utilized as an effective strategy for the treatment of PTX-resistant NSCLC.

A flat and broadband optical frequency comb generator based on two cascaded intensity modulators is proposed and experimentally demonstrated. In this scheme, we first use even or odd harmonic sidebands to generate optical frequency comb, so the bandwidth can be improved. By adjusting the power of the microwave signals and the direct current bias applied to the modulators, a flat and broadband optical frequency comb can be achieved. The scheme is relatively simple and adjustable, where the frequencies spacing vary with microwave frequency applied on modulators. 15 and 20 comb lines with the comb flatness within 1 dB can be generated. The generated spectrums can meet the requirement of OFDM modulation, and can be used for high capacity optical transmission systems in the future.

A novel scheme to optically generate a microwave signal with frequency sextupling is proposed. The proposed scheme is based on cascading an intensity modulator (IM) and a dual-parallel Mach-Zehnder modulator (DPMZM), without any optical or electrical filter. The low frequency local oscillator signal is divided into two paths, with one path driving the IM at the minimum transmission point and the other path driving the upper arm of the DPMZM. By controlling the three dc biases of the DPMZM, the third-order sidebands are generated, with other sidebands well suppressed. A 20-dB electrical spurious suppression ratio is demonstrated in the experiment. The phase noise measurements show that the phase noise performance of the generated microwave signal is not deteriorated by the optical system. The proposed scheme has no strict requirements for the modulation indexes and the generated signal exhibits advantages of high frequency tunability and purity.

We proposed a scheme based on two cascaded lithium niobate intensity modulators to generate an optical frequency comb with very high flatness. Single-drive multi-RF waveforms are used for driving the first intensity modulator, and 9 lines within 1 dB power variation can be obtained. When cascading with another intensity modulator, by specially adjusting the DC bias and the drive amplitudes of the RF signals of the two intensity modulators, 27 or 45 comb lines with a spectral power variation about 1 dB are obtained. The scheme is relatively simple and adjustable, and the frequency interval of the OFC varies with microwave frequency applied on modulators.

An optical frequency comb generator based on two-cascade intensity modulators is proposed and experimentally demonstrated. By carefully adjusting direct current biases and drive amplitudes of radio frequency signals of the two intensity modulators, the combs consisting of 3, 5, 9, 15, or 25 lines with the relative amplitude flatness within 1 dB can be generated. The scheme is relatively simple and adjustable, where the frequency spacing varies with microwave frequency applied on modulators.

A simple scheme based on two cascaded intensity modulators to generate a flat optical frequency comb (OFC) is proposed and experimentally demonstrated. By setting the two controllable parameters of the intensity modulation (RF amplitude and DC bias), five comb lines with a comb flatness within 0.6 dB are generated. When cascaded with another intensity modulator, 25 comb lines with a spectral power variation of less than 0.9 dB are obtained. The scheme, with a high unwanted-mode suppression ratio 13.1 dB and very low RF signals 0.58V π, is relatively simple, cost-efficient and adjustable, with the frequency interval of the OFC varying with the microwave frequency applied to the modulators.