Intelligent gene delivery systems based on physiologically triggered reversible shielding technology have evinced enormous interest due to their potential in vivo applications. In the present work, an acid-labile block copolymer consisting of poly(ethylene glycol) and poly(2-(dimethylamino)ethyl methacrylate) segments connected through a cyclic ortho ester linkage (PEG- a-PDMAEMA) was synthesized by atom transfer radical polymerization of DMAEMA using a PEG macroinitiator with an acid-cleavable end group. PEG- a-PDMAEMA condensed with plasmid DNA formed polyplex nanoparticles with an acid-triggered reversible PEG shield. The pH-dependent shielding/deshielding effect of PEG chains on the polyplex particles were evaluated by zeta potential and size measurements. At pH 7.4, polyplexes generated from PEG- a-PDMAEMA exhibited smaller particle size, lower surface charge, reduced interaction with erythrocytes, and less cytotoxicity compared to PDMAEMA-derived polyplexes. At pH 5.0, zeta potential of polyplexes formed from PEG- a-PDMAEMA increased, leveled up after 2 h of incubation and gradual aggregation occurred in the presence of bovine serum albumin (BSA). In contrast, the stably shielded polyplexes formed by DNA and an acid-stable block copolymer, PEG- b-PDMAEMA, did not change in size and zeta potential in 6 h. In vitro transfection efficiency of the acid-labile copolymer greatly increased after 6 h incubation at pH 5.0, approaching the same level of PDMAEMA, whereas there was only slight increase in efficiency for the stable copolymer, PEG- b-PDMAEMA.

AR-23 is a melittin-related peptide with 23 residues. Like melittin, its high α-helical amphipathic structure results in strong bactericidal activity and cytotoxicity. In this study, a series of AR-23 analogues with low amphipathicity were designed by substitution of Ala1, Ala8 and Ile17 with positively charged residues (Arg or Lys) to study the effect of positively charged residue distribution on the biological viability of the antimicrobial peptide. Substitution of Ile17 on the nonpolar face with positively charged Lys dramatically altered the hydrophobicity, amphipathicity, helicity and the membrane-penetrating activity against human cells as well as the haemolytic activity of the peptide. However, substitution on the polar face only slightly affected the peptide biophysical properties and biological activity. The results indicate that the position rather than the number of positively charged residue affects the biophysical properties and selectivity of the peptide. Of all the analogues, A(A1R, A8R, I17K), a peptide with Ala1-Arg, Ala8-Arg and Ile17-Lys substitutions, exhibited similar bactericidal activity and anti-biofilm activity to AR-23 but had much lower haemolytic activity and cytotoxicity against mammalian cells compared with AR-23. Therefore, the findings reported here provide a rationalization for peptide design and optimization, which will be useful for the future development of antimicrobial agents.

acrylamide (tNEA), was synthesized. Atom transfer radical polymerization of tNEA using a poly(ethylene glycol) (PEG) macroinitiator afforded three acid-labile thermoresponsive block copolymers: PEG-b-PtNEA 27 , PEG-b-PtNEA 56 , and PEG-b-PtNEA 73 . These block copolymers are water-soluble at low temperatures (<13 °C). Thermally induced phase transition behaviors, including the critical aggregation temperatures (CATs), of these polymers were investigated by light scattering and 1 H NMR. The results indicated that the longer the PtNEA chain length, the lower the CAT. Upon heating above the CATs, all the three polymers underwent a phase transition and formed polymeric micelles or micelle-like nanoparticles with PEG as the shell and PtNEA block as the core. Both the sizes and morphologies of the micelles were found to be affected by the heating rate and the salt concentration in the buffers. The micelles, formed through a fast heating procedure in the buffer with a relatively high salt concentration, have a smaller size and a more compacted structure. pH-dependent destabilization of the polymeric micelles prepared from PEG-b-PtNEA 73 was studied by using light scattering and Nile Red fluorescence. The results demonstrated that hydrophobic Nile Red could be loaded in the micelles that were stable at pH 7.4, but destabilized in mildly acidic media. The dissociation of the micelles and the subsequent release of Nile Red were induced by the acid-triggered hydrolysis of the orthoester groups, which was proved by the 1 H NMR spectra.

BackgroundThe nucleosome binding protein 1 (HMGN5/NSBP1) is a member of the HMGN protein family and is highly expressed in several kinds of cancer. Nevertheless, the role of NSBP1 in clear cell renal cell carcinoma (ccRCC) remains unclear. This study aimed to confirm the oncogenic role of NSBP1 in ccRCC using in vitro and in vivo models and explore the mechanism by which NSBP1 contributes to ccRCC tumorigenesis.MethodsNSBP1 expression was detected in renal tissues from 152 ccRCC patients by immunohistochemistry, and examined in ccRCC cell lines by RT-PCR and Western blot analysis. ccRCC cells were transfected by NSBP1 RNAi and cell viability, apoptosis and invasion were detected by cell vitality test, flow cytometry and transwell assay in vitro. Xenograft in nude mice was also employed to examine the tumorigenesis of ccRCC cells depleted of NSBP1.ResultsImmunohistostaining showed strong immunoreactivity of NSBP1 in all ccRCC tissues and NSBP1 expression level was associated with tumor grade (p = 0.04). NSBP1 expression at mRNA and protein levels was high in ccRCC cell lines. Knockdown of NSBP1 induced cell cycle arrest and apoptosis, and inhibited invasion in 786-O cells. Western blot analysis demonstrated increased expression of Bax and decreased expression of Bcl-2, CyclinB1, VEGF, VEGFR-2, MMP-2, MMP-9, c-fos and c-jun in 786-O cells depleted of NSBP1. In vivo study further showed that knockdown of NSBP1 affected the tumorigenesis of ccRCC cells in nude mice.ConclusionsNSBP1 plays oncogenic role in ccRCCs by promoting cell proliferation and invasion, and could be exploited as a target for ccRCC treatment.

BackgroundThe tumor acidic microenvironment, a common biochemical event in solid tumors, offers evolutional advantage for tumors cells and even enhances their aggressive phenotype. However, little is known about the molecular mechanism underlying the acidic microenvironment-induced invasion and metastasis.MethodsWe examined the expression of the acid-sending ion channel (ASIC) family members after acidic exposure using RT-PCR and immunofluoresence. Gene manipulation was applied to reveal the potential of ASIC2 on invasion, proliferation, colony formation of colorectal cancer (CRC). We assessed the in vivo tumor growth by subcutaneous transplantation and metastasis by spleen xenografts. Chromatin immunoprecipitation-sequencing was used to uncover the binding sites of NFAT1. Finally, we examined the expression of ASIC2 in CRC tissues using immunohistochemistry.ResultsAcidic exposure led to up-regulation of the acid-sensing ion channel, ASIC2, in colorectal cancer (CRC) cells. ASIC2 overexpression in CRC cell lines, SW480 and HCT116, significantly enhanced cell proliferation in vitro and in vivo, while ASIC2 knockdown had the reverse effect. Importantly, ASIC2 promoted CRC cell invasion under acidosis in vitro and liver metastasis in vivo. Mechanistically, ASIC2 activated the calcineurin/NFAT1 signaling pathway under acidosis. Inhibition of the calcineurin/NFAT pathway by cyclosporine A (CsA) profoundly attenuated ASIC2-induced invasion under acidosis. ChIP-seq assay revealed that the nuclear factor, NFAT1, binds to genes clustered in pathways involved in Rho GTPase signaling and calcium signaling. Furthermore, immunohistochemistry showed that ASIC2 expression is increased in CRC samples compared to that in adjacent tissues, and ASIC2 expression correlates with T-stage, distant metastasis, recurrence, and poor prognosis.ConclusionASIC2 promotes metastasis of CRC cells by activating the calcineurin/NFAT1 pathway under acidosis and high expression of ASIC2 predicts poor outcomes of patients with CRC.Electronic supplementary materialThe online version of this article (10.1186/s13046-017-0599-9) contains supplementary material, which is available to authorized users.

MicroRNA-145-5p (miR-145-5p) is found to be involved in tumor development and progression. However, there are few studies on the effects of miR-145-5p on bladder cancer (BC). The role of miR-145-5p in BC was predicted by analysis of cell proliferation and migration in this study. The miR-145-5p and transgelin-2 (TAGLN2) expressions were evaluated via reverse transcription-quantitative PCR (RT-qPCR) or western blot analysis. The MTT and Transwell assay assessed cell proliferation and migration. TAGLN2 targeted to miR-145-5p was determined using luciferase assays. The results showed that the miR-145-5p downregulation was found in BC. miR-145-5p overexpression inhibited cell proliferation and migration in BC. Moreover, miR-145-5p directly targeted TAGLN2, and TAGLN2 expression was increased in BC. In addition, the high expression of TAGLN2 promoted cell proliferation and migration in BC. miR-145-5p appeared to regulate TAGLN2 in BC, and it also inhibited the cell proliferation and migration. The novel miR-145-5p/TAGLN2 axis may provide new therapeutic implications for BC.

Linear reduction-degradable cationic polymers with different secondary amine densities (S2 and S3) and their nonreducible counterparts (C2 and C3) were synthesized by Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) step-growth polymerization of the dialkyne-oligoamine monomers and the diazide monomers. These polymers were studied with a goal of developing a set of new gene carriers. The buffering capacity and DNA binding ability of these polymers were evaluated by acid-base titration, gel retardation, and ethidium bromide (EB) exclusion assay. The polymers with lower amine density exhibit a weaker DNA-binding ability but a stronger buffering capacity in the range of pH 5.1 and 7.4. Particle size and zeta-potential measurements demonstrate that the polymers with higher amine density condense pDNA to form polyplexes with smaller sizes, while the disulfide bond in the backbone shows a negative effect on the condensing capability of the polymers, resulting in the formation of polyplexes with large size and nearly neutral surface. The reduction-sensitive polyplexes formed by polymer S2 or S3 can be disrupted by dithiothreitol (DTT) to release free DNA, which has been proven by the combination of gel retardation, EB exclusion assay, particles sizing, and zeta potential measurements. Cell viability measurements by MTT assay demonstrate that the reduction-degradable polymers (S2 and S3) have little cytotoxicity while the nonreducible polymers (C2 and C3) show obvious cytotoxicity, in particular, at high N/P ratios. In vitro transfection efficiencies of these polymers were evaluated using EGFP and luciferase plasmids as the reporter genes. Polymers S3 and S2 show much higher efficiencies than the nonreducible polymers C3 and C2 in the absence of 10% serum; unexpectedly, the lowest transfection efficiency has been observed for polymer S3 in the presence of serum.

The Cistanche species (“Rou Cong Rong” in Chinese) is an endangered wild species growing in arid or semi-arid areas. The dried fleshy stem of Cistanches has been used as a tonic in China for many years. Modern pharmacological studies have since demonstrated that Herba Cistanches possesses broad medicinal functions, especially for use in anti-senescence, anti-oxidation, neuroprotection, anti-inflammation, hepatoprotection, immunomodulation, anti-neoplastic, anti-osteoporosis and the promotion of bone formation. This review summarizes the up-to-date and comprehensive information on Herba Cistanches covering the aspects of the botany, traditional uses, phytochemistry and pharmacology, to lay ground for fully elucidating the potential mechanisms of Herba Cistanches’ anti-aging effect and promote its clinical application as an anti-aging herbal medicine.