Low-Molecular Weight Polyethylenimine Modified with Pluronic 123 and RGD- or Chimeric RGD-NLS Peptide: Characteristics and Transfection Efficacy of Their Complexes with Plasmid DNA.

To solve the problem of transfection efficiency vs. cytotoxicity and tumor-targeting ability when polyethylenimine (PEI) was used as a nonviral gene delivery vector, new degradable PEI polymers were synthesized via cross-linking low-molecular-weight PEI with Pluronic P123 and then further coupled with a targeting peptide R4 (RGD) and a bifunctional R11 (RGD-NLS), which were termed as P123-PEI-R4 and P123-PEI-R11, respectively. Agarose gel electrophoresis showed that both P123-PEI-R4 and P123-PEI-R11 efficaciously condense plasmid DNA at a polymer-to-pDNA w/w ratio of 3.0 and 0.4, respectively. The polyplexes were stable in the presence of serum and could protect plasmid DNA against DNaseI. They had uniform spherical nanoparticles with appropriate sizes around 100-280 nm and zeta-potentials about +40 mV. Furthermore, in vitro experiments showed that these polyplexes had lower cytotoxicity at any concentration compared with PEI 25 kDa, thus giving promise to high transfection efficiency as compared with another P123-PEI derivate conjugated with trifunctional peptide RGD-TAT-NLS (P123-PEI-R18). More importantly, compared with the other polymers, P123-PEI-R11 showed the highest transfection efficiency with relatively lower cytotoxicity at any concentration, indicating that the new synthetic polymer P123-PEI-R11 could be used as a safe and efficient gene deliver vector.

SiRNA-circFARSA-loaded porous silicon nanomaterials for pancreatic cancer treatment via inhibition of CircFARSA expression.

Novel functions and involvement of circFARSA have not been reported in pancreatic cancer; in addition, its inhibitor screening has not yet been conducted. The purpose of this study was to (1) verify circFARSA as a novel anti-cancer target for pancreatic cancer and (2) to prepare a novel anti-pancreatic cancer agent targeting circFARSA. In this study, we designed and synthesized a small interfering RNA (siRNA, named siRNA-circFARSA), which specifically inhibits circFARSA expression. Using liposomes and porous silicon nanoparticles (pSiNPs) as siRNA delivery system, we prepared liposome-siRNA-circFARSA and pSiNP-PEI-siRNA-circFARSA and investigated their anti-cancer mechanism by quantitative real-time PCR and western blotting. Cell proliferation curves and transwell migration assays were performed to investigate the effect of siRNAs proliferation and migration capabilities of cancer cells. Patient-derived tumor xenograft mouse models were used to investigate the anti-cancer effects in vivo. The data showed that both liposome-siRNA-circFARSA and pSiNP-PEI-siRNA-circFARSA (Si: 0.7 µg/mL) significantly inhibited the proliferation and migration of pancreatic cancer cells in vitro. However, the biological safety and in vivo anti-cancer effects of pSiNP-PEI-siRNA-circFARSA (Si: 22.4 µg/mL) were higher than those of liposome-siRNA-circFARSA. The results showed that siRNA-circFARSA could inhibit the expression of circFARSA and then BCL-2 protein expression, thereby leading to pancreatic cancer cell apoptosis after transportation into pancreatic cancer cells. Therefore, this study provides tools for pancreatic cancer treatment in the future, as it (1) verified circFARSA as a novel target for pancreatic cancer treatment, and (2) prepared a novel anti-pancreatic cancer agent (pSiNP-PEI-siRNA-circFARSA).

In Vivo Ovarian Cancer Gene Therapy Using CRISPR-Cas9.

Clustered regularly interspaced short palindromic repeats (CRISPR)-caspase 9 (Cas9) genome editing technology holds great promise for the field of human gene therapy. However, a lack of safe and effective delivery systems restricts its biomedical application. Here, a folate receptor-targeted liposome (F-LP) was used to deliver CRISPR plasmid DNA co-expressing Cas9 and single-guide RNA targeting the ovarian cancer-related DNA methyltransferase 1 (DNMT1) gene (gDNMT1). F-LP efficiently bound the gDNMT1 plasmid and formed a stable complex (F-LP/gDNMT1) that was safe for injection. F-LP/gDNMT1 effectively mutated endogenous DNMT1 in vitro, and then expressed the Cas9 endonuclease and downregulated DNMT1 in vivo. The tumor growth of both paclitaxel-sensitive and -resistant ovarian cancers were inhibited by F-LP/gDNMT1, which shows fewer adverse effects than paclitaxel injection. Therefore, CRISPR-Cas9-targeted DNMT1 manipulation may be a potential therapeutic regimen for ovarian cancer, and lipid-mediated delivery systems represent promising delivery vectors of CRISPR-Cas9 technology for precise genome editing therapeutics.

A Biodegradable Polyethylenimine-Based Vector Modified by Trifunctional Peptide R18 for Enhancing Gene Transfection Efficiency In Vivo.

Lack of capacity to cross the nucleus membrane seems to be one of the main reasons for the lower transfection efficiency of gene vectors observed in vivo study than in vitro. To solve this problem, a new non-viral gene vector was designed. First, a degradable polyethylenimine (PEI) derivate was synthesized by crosslinking low-molecular-weight (LMW) PEI with N-octyl-N-quaternary chitosan (OTMCS), and then adopting a designed trifunctional peptide (RGDC-TAT-NLS) with good tumor targeting, cell uptake and nucleus transport capabilities to modify OTMCS-PEI. The new gene vector was termed as OTMCS-PEI-R18 and characterized in terms of its chemical structure and biophysical parameters. Gene transfection efficiency and nucleus transport mechanism of this vector were also evaluated. The polymer showed controlled degradation and remarkable buffer capabilities with the particle size around 100-300 nm and the zeta potential ranged from 5 mV to 40 mV. Agraose gel electrophoresis showed that OTMCS-PEI-R18 could effectively condensed plasmid DNA at a ratio of 1.0. Besides, the polymer was stable in the presence of sodium heparin and could resist digestion by DNase I at a concentration of 63U DNase I/DNA. OTMCS-PEI-R18 also showed much lower cytotoxicity and better transfection rates compared to polymers OTMCS-PEI-R13, OTMCS-PEI and PEI 25 KDa in vitro and in vivo. Furthermore, OTMCS-PEI-R18/DNA complexes could accumulate in the nucleus well soon and not rely on mitosis absolutely due to the newly incorporated ligand peptide NLS with the specific nuclear delivery pathway indicating that the gene delivery system OTMCS-PEI-R18 could reinforce gene transfection efficiency in vivo.