MicroRNA-214 enriched exosomes from human cerebral endothelial cells (hCEC) sensitize hepatocellular carcinoma to anti-cancer drugs

Hepatocellular carcinoma (HCC) is the most common primary liver tumor worldwide. Current medical therapy for HCC has limited efficacy. The present study tests the hypothesis that human cerebral endothelial cell-derived exosomes carrying elevated miR-214 (hCEC-Exo-214) can amplify the efficacy of anti-cancer drugs on HCC cells. Treatment of HepG2 and Hep3B cells with hCEC-Exo-214 in combination with anti-cancer agents, oxaliplatin or sorafenib, significantly reduced cancer cell viability and invasion compared with monotherapy with either drug. Additionally, the therapeutic effect of the combination therapy was detected in primary tumor cells derived from patients with HCC. The ability of hCEC-Exo-214 in sensitizing HCC cells to anti-cancer drugs was specific, in that combination therapy did not affect the viability and invasion of human liver epithelial cells and non-cancer primary cells. Furthermore, compared to monotherapy with oxaliplatin and sorafenib, hCEC-Exo-214 in combination with either drug substantially reduced protein levels of P-glycoprotein (P-gp) and splicing factor 3B subunit 3 (SF3B3) in HCC cells. P-gp and SF3B3 are among miR-214 target genes and are known to mediate drug resistance and cancer cell proliferation, respectively. In conclusion, the present in vitro study provides evidence that hCEC-Exo-214 significantly enhances the anti-tumor efficacy of oxaliplatin and sorafenib on HCC cells

Arabidopsis Ovate Family Proteins, a Novel Transcriptional Repressor Family, Control Multiple Aspects of Plant Growth and Development

, AtOFP4 has been shown to regulate secondary cell wall formation by interact with KNOTTED1-LIKE HOMEODOMAIN PROTEIN 7 (KNAT7), and AtOFP5 has been shown to regulate the activity of a BEL1-LIKEHOMEODOMAIN 1(BLH1)-KNAT3 complex during early embryo sac development, but little is known about the function of other AtOFPs. genes may also have diverse functions in regulating plant growth and development. Further analysis suggested that AtOFP1 regulates cotyledon development in a postembryonic manner, and global transcript profiling revealed that it suppress the expression of many other genes.Our results showed that AtOFPs function as transcriptional repressors and they regulate multiple aspects of plant growth and development. These results provided the first overview of a previously unknown transcriptional repressor family, and revealed their possible roles in plant growth and development

The GCR2 Gene Family Is Not Required for ABA Control of Seed Germination and Early Seedling Development in Arabidopsis

BACKGROUND: The plant hormone abscisic acid (ABA) regulates diverse processes of plant growth and development. It has recently been proposed that GCR2 functions as a G-protein-coupled receptor (GPCR) for ABA. However, the structural relationships and functionality of GCR2 have been challenged by several independent studies. A central question in this controversy is whether gcr2 mutants are insensitive to ABA, because gcr2 mutants were shown to display reduced sensitivity to ABA under one experimental condition (e.g. 22 degrees C, continuous white light with 150 micromol m(-2) s(-1)) but were shown to display wild-type sensitivity under another slightly different condition (e.g. 23 degrees C, 14/10 hr photoperiod with 120 micromol m(-2) s(-1)). It has been hypothesized that gcr2 appears only weakly insensitive to ABA because two other GCR2-like genes in Arabidopsis, GCL1 and GCL2, compensate for the loss of function of GCR2. PRINCIPAL FINDINGS: In order to test this hypothesis, we isolated a putative loss-of-function allele of GCL2, and then generated all possible combinations of mutations in each member of the GCR2 gene family. We found that all double mutants, including gcr2 gcl1, gcr2 gcl2, gcl1 gcl2, as well as the gcr2 gcl1 gcl2 triple mutant displayed wild-type sensitivity to ABA in seed germination and early seedling development assays, demonstrating that the GCR2 gene family is not required for ABA responses in these processes. CONCLUSION: These results provide compelling genetic evidence that GCR2 is unlikely to act as a receptor for ABA in the context of either seed germination or early seedling development

Dissecting mitogen-activated protein kinase cascades involving arabidopsis MKK6

Mitogen-activated protein (MAP) kinase cascades act as critical components in the signalling pathways of all eukaryotic cells. They play a pivotal role in the transduction of extra- and intra-cellular stimuli and regulate cell growth, proliferation, differentiation and cell death, through sequential activation of MAP kinase kinase kinases (MAPKKKs), MAP kinase kinases (MKKs), and MAP kinases (MPKs). These three components form modules that control the phosphorylation of various substrates including transcription factors, enzymes, and cytoskeleton-associated proteins. In the Arabidopsis genome, over 60 MAPKKKs (AtMKKK), 10 MAPKKs (AtMKK), and 20 MAPKs (AtMPK) have been identified. The smaller number of AtMKKs suggests that diverse signals may converge and be integrated at the level of AtMKK. Among the ten AtMKKs, MKK6 has been proposed to play a role in regulating cytokinesis. However, little is known about the hierarchal phosphorylation system containing MKK6. In this Ph.D. project, I aimed to dissect the MAP kinase cascades involving MKK6 in Arabidopsis. I investigated potential targets of MKK6. Four MAP kinases were identified to interact with, and be phosphorylated by, MKK6, namely, MPK4, MPK6, MPK11, and MPK13. Among them, MPK13 is developmentally co-expressed with MKK6, and both MPK13 and MKK6 display high PromoterScience, Faculty ofBotany, Department ofGraduat

Remote Control Techniques to the Digital Storage Oscilloscope by GPIB and VISA

Some techniques of controlling remotely the digital storage oscilloscope were proposed including VISA, VXIplug&play drivers, TVC and IVI-COM drivers. By means of GPIB and VISA, several application development environments could be used to develop remote control techniques to the digital storage oscilloscope. The programming language of Visual C++ was used to develop software. With the help of VISA and the dynamic link library, remote control to the digital storage oscilloscope through network was completed. All operations to the digital storage oscilloscope including parameters setup, data acquisition, waveform acquisition and storage, data processing were implemented in a remote place. The results show that the techniques of remote control are convenient and efficient and fit for experiments of scientific research and practical projects. DOI: http://dx.doi.org/10.11591/telkomnika.v11i4.233

GIGANTEA is a co-chaperone which facilitates maturation of ZEITLUPE in the Arabidopsis circadian clock

Circadian clock systems help establish the correct daily phasing of the behavioral, developmental, and molecular events needed for the proper coordination of physiology and metabolism. The circadian oscillator comprises transcription-translation feedback loops but also requires post-translational processes that regulate clock protein homeostasis. GIGANTEA is a unique plant protein involved in the maintenance and control of numerous facets of plant physiology and development. Through an unknown mechanism GIGANTEA stabilizes the F-box protein ZEITLUPE, a key regulator of the circadian clock. Here, we show that GIGANTEA has general protein chaperone activity and can act to specifically facilitate ZEITLUPE maturation into an active form in vitro and in planta. GIGANTEA forms a ternary complex with HSP90 and ZEITLUPE and its co-chaperone action synergistically enhances HSP90/HSP70 maturation of ZEITLUPE in vitro. These results identify a molecular mechanism for GIGANTEA activity that can explain its wide-ranging role in plant biology

Involvement of Arabidopsis RACK1 in Protein Translation and Its Regulation by Abscisic Acid1[C][W][OA]

Earlier studies have shown that RACK1 functions as a negative regulator of abscisic acid (ABA) responses in Arabidopsis (Arabidopsis thaliana), but the molecular mechanism of the action of RACK1 in these processes remains elusive. Global gene expression profiling revealed that approximately 40% of the genes affected by ABA treatment were affected in a similar manner by the rack1 mutation, supporting the view that RACK1 is an important regulator of ABA responses. On the other hand, coexpression analysis revealed that more than 80% of the genes coexpressed with RACK1 encode ribosome proteins, implying a close relationship between RACK1’s function and the ribosome complex. These results implied that the regulatory role for RACK1 in ABA responses may be partially due to its putative function in protein translation, which is one of the major cellular processes that mammalian and Saccharomyces cerevisiae RACK1 is involved in. Consistently, all three Arabidopsis RACK1 homologous genes, namely RACK1A, RACK1B, and RACK1C, complemented the growth defects of the S. cerevisiae cross pathway control2/rack1 mutant. In addition, RACK1 physically interacts with Arabidopsis Eukaryotic Initiation Factor6 (eIF6), whose mammalian homolog is a key regulator of 80S ribosome assembly. Moreover, rack1 mutants displayed hypersensitivity to anisomycin, an inhibitor of protein translation, and displayed characteristics of impaired 80S functional ribosome assembly and 60S ribosomal subunit biogenesis in a ribosome profiling assay. Gene expression analysis revealed that ABA inhibits the expression of both RACK1 and eIF6. Taken together, these results suggest that RACK1 may be required for normal production of 60S and 80S ribosomes and that its action in these processes may be regulated by ABA