The Anti-tumor Nano-drug Carrier System Modified by theNuclear Localization Signal Peptide / 中国生物化学与分子生物学报

Nano-drug carrier systems, as the controllable and targeting tool to deliver drugs, can effectively improve the drug bioavailability, enhance their therapeutic outcomes and reduce side effects, mainly through protecting drugs from rapid enzymatic degradation and blood clearance and ensuring them to be delivered to the targeting sites. The nano-drug carrier system owns broad application prospects in the biomedical field and attracts increasing attention in both functional materials and anti-tumor research. Recently, functional surface modification with functional biomolecules to improve the biocompatibility and drug bioactivity is a hot topic in nano medicine research. The nucleus is the main site of action for manyanti-tumor substances. And nuclear localization signal (NLS) peptides, as a type of functional peptides with nuclear-targeting activity, can penetrate through biological membranes and target the nucleus and is considered to be a universal tool for constructing nano-drug carrier systems. The use of NLS peptides to construct a functionalized nano-drug carrier system with nuclear targeting ability has important application values in the field of anti-tumor therapy. Although the synthesis process of nuclear-targeted functionalized nano-drug carrier system has been developed, due to the high preparation cost and complex synthesis process, there is still a long research process in the successful translation of nuclear-targeted nanocarriers from the experimental stage to the clinical stage. This review mainly focuses on the composition and construction of the nuclear-targeted functionalized nano-drug carrier system, analyzes its nuclear entry methods and conditions, and prospects the development of the anti-tumor nano-drug carrier system in the future based on the current challenges.

Construction and expression of the eukaryotic expression vector of wild-type p27 and lacking the nuclear localization signal p27 / 西安交通大学学报(医学版)

【Objective】 To construct the eukaryotic expression vector carrying the human wild-type p27 and lacking nuclear localization signal p27△NLS coding sequences， and the express them in HEK293T cells， which may contribute to investigating the different locations and roles of p27 in the cytoplasm and nucleus. 【Methods】 Total RNA was prepared from human breast cancer MCF7 cells， and cDNA was obtained by reverse transcription-polymerase chain reaction （RT-PCR）. After amplification of the p27 CDs and non-NLS fragments by PCR， full length p27WT （CDKN1B， NM_004064.5） and p27△NLS coding regions were obtained. PCR products were then subcloned into the eukaryotic expression vector pCMV-Blank. After identification with bacterial PCR， double restriction enzyme digestion and sequencing， they were defined officially as pCMV-p27WT and pCMV-p27△NLS， respectively. The recombinant plasmids were transfected into HEK293T cells by electroporation. After 48 h， the levels of p27 protein in the cytoplasm and nucleus were detected by Western blotting. 【Results】 The sequencing results showed that the sequences of p27WT and p27△NLS inserted into the plasmids were both correctly consistent with that of NM_004064.5. After transfection with pCMV-p27WT， total p27 protein expression was increased and distributed in both the cytoplasm and nucleus of HEK293T cells. After transfection with pCMV-p27△NLS， p27 protein was significantly increased and almost entirely localized in the cytoplasm of HEK293T cells. 【Conclusion】 The eukaryotic expression plasmids of human p27WT and p27△NLS coding sequences were successfully constructed and overexpressed in HEK293T cells. This research may lay a foundation for investigating the biological function of p27 in the cell cycle progression of tumor cells.

Experimental study of combining ultrasound targeted microbubble destruction with nuclear localization signal peptide to enhance gene transfection in treatment of canines myocardial infarction / 中华超声影像学杂志

Objective To improve the canines myocardial infarction curative effect by using ultrasound targeted microbubble destruction (UTMD) combining with nuclear localization signal(NLS) peptide to increase hAng-1 gene transfection efficiency.Methods Forty-six canines were randomly divided into 4 groups (n=10 in each group) after the models of myocardial infarction were prepared.Group A were untreated control;Group B were transfected with hAng-1;Group C were transfected with UTMD+hAng-1;Group D were transfected with UTMD+NLS nuclear localization signal+hAng-1.The therapeutic agents were intravenously injected at one week after myocardial infarction in each group,and the ultrasound were irradiated at the precardium in group C and D.①Echocardiography was used before and at one week after myocardial infarction and 28 days after gene transfection.Two-dimensional echocardiography was used to detect cardiac function,the left ventricular ejection fraction,the left ventricular wall motion and the myocardial contrast echocardiography were used to detect myocardial perfusion of all canines in the four groups.②On twenty-eight days after gene transfection,mRNA and Western Blot were used to detect the expression of hAng-1.Immunohistochemistry was used to detect capillary density of peri-infarct area and microvessel density (MVD).Masson′s trichromatic staining and gross specimen were used to evaluate the degree and the area of myocardial fibrosis.The gene transfection efficiency and the curative effect of all the four groups were evaluated and compared.Results ①Before myocardial infarction,in four groups canine ventricular wall motion and cardiac function were normal,and myocardial filling defect was not showed by myocardial contrast echocardiography.At one week after myocardial infarction,the left ventricular anterior and interval walls motion and the left ventricular ejection fraction in the four groups were significantly decreased.Myocardial contrast echocardiography showed anterior and interval walls myocardial filling defect.There was no significant difference among the four groups(P>0.05);On 28 days after gene transfection the left ventricular ejection fraction in the four group were increased in an order of group A,B,C,D,there was significant difference when comparing group C and D with other groups separately(P<0.05).Myocardial contrast echocardiography showed much contrast filling in the infarction and surrounding area in group D,a little contrast filling in group C and filling defect in group A and group B,there was significant difference when comparing group C and D with other groups separately(P<0.05).②RT-PCR and Western Blot showed the hAng-1 mRNA and protein expression in group D were higher than those in the other group.There was significant difference when comparing group C and group D with other groups separately(P<0.05).③Immunofluorescence showed the capillary densities were(4.7±1.6)/mm2,(11.2±2.8)/mm2,(70.0±6.4)/mm2 and (85.3±7.0)/mm2 in group A,group B,group C and group D.The differences were statistically significant compared group C and group D with other groups (P<0.05).④Masson′s trichromatic staining and cardiac gross specimen showed that the degree and area of myocardial fibrosis were gradually reduced in an order of group A,B,C,D.Conclusions UTMD and NLS peptide could effectively transfect hAng-1 gene and it provided a novel strategy of gene treatment for ischemic heart disease.

Experiment study on the transfection of exogenous genes promoted by ultrasound-targeted microbubbles combined with a peptide nucleic acid binding nuclear localization signal / 中华超声影像学杂志

Objective To increase the transfection of EGFP-N3 plasmids into 293T cells using ultrasound-targeted microbubbles delivery(UTMD) mediated a peptide nucleic acid (PNA) binding nuclear localization signal (NLS).Methods Antibody-targeted microbubbles were used in the experiments which can specifically recognize the SV40T antigen receptor.The SV40T antigen receptors were expressed on the membranes of 293T cells.The PNA containing the NLS were inserted in the EGFP-N3 plasmid DNA,which increased nuclear localization.Ultrasound-targeted microbubble delivery (UTMD) and the PNA binding NLS were utilized to improve the cytoplasmic import of plasmids and the nuclear intake of the plasmid from the cytoplasm,respectively.The study was divided into five groups:Contrast (group A),Common microbubble + DNA (group B),Antibody-targeted microbubbles + DNA (group C),Common microbubbles + NLS-PNA-DNA (group D),Antibody-targeted microbubbles + NLS-PNA-DNA (group E).Fluorescence microscope was used to observe the fluorescent light in each group;flow cytometry to test the transfection;RT-PCR and Western blot to detect genes' mRNA and protein expression level.Results Ultrasound and antibody-targeted microbubble delivery (UTMD) significantly enhanced the cytoplasmic intake of exogenous genes and maintained high cell viability(＞80％).Fluorescent microscope showed that the quantities of green fluorescence in cells were increased successfully.The transfection results of flow cytometry were 0,(9.30 ± 0.46)％,(26.46 ± 2.01)％,(29.54 ± 0.62)％,(45.72 ± 1.86)％,respectively,and the differences were statistically significant(P ＜0.05).The relative mRNA and protein expression in group E were greater than those in group C and D respectively (P ＜0.05).Conclusions UTMD combined with antibody-targeted microbubbles and a PNA binding NLS plasmid can significantly improve transfection efficiency of exogenous genes by enhancing both cytoplasmic and nuclear DNA import.

The molecular mechanism for nuclear transport and its application / 대한해부학회지

Transportation between the cytoplasm and the nucleoplasm is critical for many physiological and pathophysiological processes including gene expression, signal transduction, and oncogenesis. So, the molecular mechanism for the transportation needs to be studied not only to understand cell physiological processes but also to develop new diagnostic and therapeutic targets. Recent progress in the research of the nuclear transportation (import and export) via nuclear pore complex and four important factors affecting nuclear transport (nucleoporins, Ran, karyopherins, and nuclear localization signals/nuclear export signals) will be discussed. Moreover, the clinical significance of nuclear transport and its application will be reviewed. This review will provide some critical insight for the molecular design of therapeutics which need to be targeted inside the nucleus.

The enhanced effect of nuclear localization signal peptide during the ultrasound targeted microbubbles ;destruction mediated gene transfection / 中华超声影像学杂志

Objective To investigate the transfection efficiency combining ultrasound targeted microbubbles destruction(UTMD)and nuclear localization signal(NLS)peptide for facilitating the plasmid of enhanced green fluorescent protein (pEGFP) into nucleus.Methods This study was divided into 3 groups,group A:UTMD+ pEGFP;group B:UTMD+ NLS + pEGFP;group C:Lipo3000 + pEGFP.The NLS was labeled by FITC and pEGFP was marked by Cy3.The different mole ratio was adjusted between NLS and pEGFP for observing the best ratio of combination.The human umbilical vein endothelial cells (HUVEC) were transfected by the optimum ultrasonic irradiation parameters and the optimal NLS∕pEGFP mole ratio.Six hours after transfection,the rate of Cy3 labeled pDNA into cells and nuclear were detected by flow cytometer and laser confocal microscope respectively.Forty-eight hours after transfection,the transfection efficiency was detected by flow cytometer;the survival rate of cells was measured by CCK8. RT-PCR and Western technology were used to detect the relative expression amount of mRNA and protein. The above indicators were compared among 3 groups,which were used to evaluate the enhanced effect of NLS in UTMD mediated gene transfection.Results ① Six hours after transfection,the NLS with green fluorescence and pEGFP with red fluorescence can show at the same site and signal intensity within the cell, that suggested a combination between them,agarose gel electrophoresis showed that the best molar ratio of NLS∕pEGFP combining was 10 4 ∶1 .②Six hours after transfection,the rates of pEGFP into the cells were (63±12)%,(80±10)% and(92±8)%;the rates of pEGFP into the nucleus were(1 7±3)%,(50±12)%and(35±8)% in 3 groups respectively(P 80% in all groups;the transfection efficiency,relative quantity of mRNA and protein expression were increased gradually.There were significant differences among 3 groups(P <0.05).They were 1 .6,2.3 and 2.4 times in group B than those in group A,still lower than those in group C.Conclusions The UTMD combining NLS can promote the pEGFP into nucleus for improving the transfection efficiency.The NLS peptide can play an enhanced effect as a new strategy of UTMD.

The N-terminal 33 amino acid domain of Siva-1 is sufficient for nuclear localization

Siva-1 induces apoptosis in multiple pathological processes and plays an important role in the suppression of tumor metastasis, protein degradation, and other functions. Although many studies have demonstrated that Siva-1 functions in the cytoplasm, a few have found that Siva-1 can relocate to the nucleus. In this study, we found that the first 33 amino acid residues of Siva-1 are required for its nuclear localization. Further study demonstrated that the green fluorescent protein can be imported into the nucleus after fusion with these 33 amino acid residues. Other Siva-1 regions and domains showed less effect on Siva-1 nuclear localization. By site-mutagenesis of all of these 33 amino acid residues, we found that mutants of the first 1-18 amino acids affected Siva-1 nuclear compartmentalization but could not complete this localization independently. In summary, we demonstrated that the N-terminal 33 amino acid residues were sufficient for Siva-1 nuclear localization, but the mechanism of this translocation needs additional investigation.

The Nucleocytoplasmic Transport of Viral Proteins / 中国病毒学·英文版

Molecules can enter the nucleus by passive diffusion or active transport mechanisms, depending on their size. Small molecules up to size of 50-60 kDa or less than 10 nm in diameter can diffuse passively through the nuclear pore complex (NPC), while most proteins are transported by energy driven transport mechanisms. Active transport of viral proteins is mediated by nuclear localization signals (NLS), which were first identified in Simian Virus 40 large T antigen and had subsequently been identified in a large number of viral proteins. Usually they contain short stretches of lysine or arginine residues. These signals are recognized by the importin super-family (importin α and β) proteins that mediate the transport across the nuclear envelope through Ran-GTP. In contrast, only one class of the leucine-rich nuclear export signal (NES) on viral proteins is known at present. Chromosome region maintenance 1 (CRM1) protein mediates nuclear export of hundreds of viral proteins through the recognition of the leucine-rich NES.

Identification and Characterization of Nuclear Localization Signals within the Nucleocapsid Protein VP15 of White Spot Syndrome Virus / 中国病毒学·英文版

The nucleocapsid protein VP15 of white spot syndrome virus (WSSV) is a basic DNA-binding protein. Three canonical bipartite nuclear localization signals (NLSs), called NLS1 (aa 11-27), NLS2 (aa 33-49) and NLS3 (44-60), have been detected in this protein, using the ScanProsite computer program. To determine the nuclear localization sequence of VP15, the full-length open reading frame, or the sequence of one of the three NLSs, was fused to the green fluorescent protein (GFP) gene, and transiently expressed in insect Sf9 cells. Transfection with full-length VP15 resulted in GFP fluorescence being distributed exclusively in the nucleus. NLS 1 alone could also direct GFP to the nucleus, but less efficiently. Neither of the other two NLSs (NLS2 and 3) was functional when expressed alone, but exhibited similar activity to NLS1 when they were expressed as a fusion peptide. Furthermore, a mutated VP15, in which the two basic amino acids (11RR12) of NLSI were changed to two alanines (11AA12), caused GFP to be localized only in the cytoplasm of Sf9 cells. These results demonstrated that VP15, as a nuclear localization protein, needs cooperation between its three NLSs, and that the two residues (11RR12) of NLS1 play a key role in transporting the protein to the nucleus.

Through The Door to The Nucleus:Progress on Nuclear Translocation Mechanism / 生物化学与生物物理进展

DNA replication and RNA biogenesis happen in the cell nucleus,while protein synthesis occurs in the cytoplasm. Integration of these activities depends on function proteins′ selective transport between the two sub-dimensions. It is a signal mediated process, which needs energy and the participation of soluble factors. By introduction of progress on function protein regulated nuclear translocation, its potential medical application has been explored. With deeper investigation in this field, it will significantly promote the design of anti-virus and gene vector therapy.

Expression and Purification of a hbFGF Lacking Nuclear Localization Signal / 中国药科大学学报

AIM:To study the mechanism of the unique export of one of human basic fibroblast growth factor (hbFGF) forms lacking the N-terminal nuclear localization signal (NLS),we high expressed and purified this hbFGF form in E.coli strain BL21(DE3).METHODS:The cDNA fragment of the hbFGF amplified by polymerase chain reaction (PCR) was cloned into the expression vector pET3c and expressed in BL21(DE3) by IPTG induction.The expressed hbFGF was purified by ionic exchange and heparin affinity chromatography from the supernatant of bacteria lysate.The mitogenic activity was measured by MTT.RESULTS:The expression level of hbFGF in E.coli was about 20% of the total cellular protein.The appreciable mitogenic activity of the purified hbFGF was comparable to that of hbFGF standard.CONCLUSION:The BL21(DE3)/ pET3c expression system could be used to high express hbFGF lacking NLS.The purified recombinant hbFGF was prepared and sufficient for further study.