Zongguang Tai

Reducible self-assembling cationic polypeptide-based micelles mediate co-delivery of doxorubicin and microRNA-34a for androgen-independent prostate cancer therapy.

The co-delivery of chemotherapeutic drugs and microRNAs (miR) represents a promising strategy for tumor therapy due to the synergistic effect achieved. In the present study, hydrophobic doxorubicin (DOX) and negatively charged miR-34a were simultaneously delivered via a reducible self-assembling disulfide cross-linked stearyl-peptide-based micellar system (SHRss) using poly(l-arginine)-poly(l-histidine)-stearoyl as the copolymer building unit. The nanoscale SHRss micelles exhibited a low critical micelle concentration (CMC) with positive surface charge. In addition, the present micellar system facilitated the escape of miR-34a from the endosome and release of DOX into the cell nucleus, leading to the downregulation of silent information regulator 1 (SIRT1) expression and inhibition of DU145 and PC3 androgen-independent prostate cancer cell proliferation. In addition, DOX and miR-34a, delivered by SHRss micelles, passively targeted tumor tissue. Furthermore, a synergistic anti-proliferative effect was observed compared with DOX or miR-34a treatment alone in vivo. Our results demonstrate that the SHRss micelles developed in the present study represent a promising approach for combined delivery of gene agents and hydrophobic chemotherapeutic drugs in cancer therapy.

Biodegradable stearylated peptide with internal disulfide bonds for efficient delivery of siRNA in vitro and in vivo.

RNA-based delivery system for cancer therapy remains a challenge. In this study, a stearyl-peptide (SHR) was synthesized using arginine, histidine, cysteine, and stearyl moieties. Further, the stearyl-peptides were cross-linked by disulfide bonds to obtain cross-linked polypeptides (SHRss) with different molecular weight (SHRss1, SHRss2, SHRss3, SHRss4). The SHRss could effectively condense small interfering RNA (siRNA) into polyplexes with a hydrodynamic size of 100-300 nm and zeta potential of 20-40 mV. Flow cytometry and confocal laser scanning microscope studies revealed high cellular uptake and rapid dissociation behavior of SHRss2/siRNA complexes. Long-lasting high concentration of siRNA in cytoplasm was observed even at 24 h after SHRss2/Cy3-siRNA transfection. Compared with SHR, the SHRss showed much improved siRNA interference efficiency targeting luciferase on Luc-Hela cells. Moreover, SHRss2 exhibited higher interference efficiency and slower decay rate on Luc-Hela cells than Lipofectamine 2000 and SHR. In addition, much weaker expression of red fluorescence protein was also observed on SHRss2/simCh-treated mCherry-HEK293 cells than Lipofectamine 2000 and SHR. The SHRss did not induce cytotoxicity at siRNA concentrations of 25-200 nM under transfection. The in vivo studies demonstrated the gene interference efficiency of SHRss2/siRNA complexes. Our studies indicated that the SHRss are promising and efficient nonviral vectors for siRNA delivery.

Aptamer-mediated delivery of docetaxel to prostate cancer through polymeric nanoparticles for enhancement of antitumor efficacy.

Treatment of aggressive prostate cancer remains a great challenge due to inadequate drug distribution into the cancerous lesions after administration. This study aimed to develop aptamer-anchored nanoparticles (apt-NPs) for systemic delivery of docetaxel (DTX) and to evaluate the tumoricidal activity against the prostate cancer in vitro and in vivo. DTX-loaded apt-NPs (DTX-apt-NPs) were prepared by a solvent diffusion technique using functional PLGA-b-PEG and sodium oleate. DTX-apt-NPs were characterized by in vitro release, antitumor activity, cellular uptake and cytotoxic mechanisms. Pharmacokinetics and tissue distribution studies were performed in rats to investigate the biofate of DTX-apt-NPs. Finally, the in vivo antitumor efficacy was examined on the LNCaP cells xenograft tumor model. The resulting DTX-apt-NPs were 93.6nm in particle size with narrow distribution and possessed a high entrapment efficiency (97.62%) and acceptable drug loading (8.91%). DTX-apt-NPs demonstrated an enhanced in vitro antitumor effect and marked cellular uptake compared with the solution formulation or conventional nanoparticles. The intracellular trafficking of DTX-apt-NPs was shown to be an active transport process involving the clathrin-dependent endocytosis. Anti-PSMA aptamer-mediated delivery was assumed mainly responsible for the enhanced antitumor efficacy. DTX-apt-NPs that can target to PSMA-overexpressed prostate cancer provide a feasible approach for systemic delivery of DTX to the cancerous prostate to achieve a fine prognosis.

Study on the prostate cancer-targeting mechanism of aptamer-modified nanoparticles and their potential anticancer effect in vivo

Ligand-mediated prostate cancer (PCa)-targeting gene delivery is one of the focuses of research in recent years. Our previous study reported the successful preparation of aptamer-modified nanoparticles (APT-NPs) in our laboratory and demonstrated their PCa-targeting ability in vitro. However, the mechanism underlying this PCa-targeting effect and their anticancer ability in vivo have not yet been elucidated. The objective of this study was to assess the feasibility of using APT-NPs to deliver micro RNA (miRNA) systemically to PCa cells, to testify their tumor-targeting efficiency, and to observe their biodistribution after systemic administration to a xenograft mouse model of PCa. In addition, the effect of APT depletion and endocytosis inhibitors on cellular uptake was also evaluated quantitatively in LNCaP cells to explore the internalization mechanism of APT-NPs. Finally, blood chemistry, and renal and liver function parameters were measured in the xenograft mouse model of PCa to see whether APT-NPs had any demonstrable toxicity in mice in vivo. The results showed that APT-NPs prolonged the survival duration of the PCa tumor-bearing mice as compared with the unmodified NPs. In addition, they had a potential PCa-targeting effect in vivo. In conclusion, this research provides a prototype for the safe and efficient delivery of miRNA expression vectors to PCa cells, which may prove useful for preclinical and clinical studies on the treatment of PCa.

Reduction-responsive cross-linked stearyl peptide for effective delivery of plasmid DNA.

Low efficiency and significant toxicity are the main obstacles to successful gene delivery. We have developed a cationic reduction-responsive vector based on a disulfide cross-linked stearylated polyarginine peptide modified with histidine (C-SHR) for DNA delivery. The structure of the C-SHR was characterized, and the in vitro and in vivo transfection efficiency and cytotoxicity of C-SHR/plasmid DNA complexes were examined. Compared with non-cross-linked stearylated polyarginine peptide (SHR), C-SHR increased the intracellular uptake and dissociation behavior of the complexes. In addition, the gene transfection efficiency of C-SHR/plasmid DNA complexes in HEK293 and HeLa cells was improved and was comparable with that of bPEI-25K/plasmid DNA complexes, and the cytotoxicity of C-SHR was significantly less than that of bPEI-25K. Importantly, the in vivo gene transfection efficiency of C-SHR/plasmid DNA complexes was five fold higher than that of SHR/plasmid DNA complexes, suggesting that C-SHR is an efficient non-viral vector for DNA delivery.

Reducible chimeric polypeptide consisting of octa-d-arginine and tetra-l-histidine peptides as an efficient gene delivery vector

Cationic oligopeptide as a nonviral gene delivery vector has aroused much research interest recently, but its further application is limited by its low transfection efficiency. In the present study, we have created a high-efficiency gene vector by using octa-d-arginine and tetra-l-histidine to form a disulfide cross-linked chimeric polypeptide and used this vector to deliver the therapeutic gene tumor-necrosis-factor-related apoptosis-inducing ligand (TRAIL) to see whether the gene could be transferred and could exert antitumor effects in vitro and in vivo. The result showed that the newly designed vector was able to condense DNA into nanosized polyplexes effectively, thus facilitating its transmembrane transport, promoting its endosomal escape, and finally enabling degradation within the cell. Our study has demonstrated that this chimeric polypeptide is an effective gene carrier in cancer therapy.

Current Status of Gene Therapy for Hepatocellular Carcinoma, with a Focus on Gene Delivery Approaches

Hepatocellular carcinoma (HCC) is a malignancy with high morbidity and mortality rates, especially in East Asia. Gene therapy is a potential approach for treating HCC. An efficient and safe gene delivery method is a crucial factor for HCC gene therapy. In recent years, gene delivery systems, including viral and non-viral gene vectors, bacteria, and physical methods, have undergone substantial development. Among them, various non-viral vectors have been studied widely and in detail because they are relatively safe and have a high capacity. In this review, we focus on current and emerging HCC delivery techniques and address the challenges involved in the use and improvement of non-viral vectors.

Synergistic effect of reduced polypeptide micelle for co-delivery of doxorubicin and TRAIL against drug-resistance in breast cancer

Cationic peptides as a non-viral gene vector have become a hotspot of research because of their high transfection efficcacy and safety. Based on our previous study, we synthesized a cationic reduction-responsive vector based on disulfide cross-linked L-arginine, L-histidine and lipoic acid (LHRss) as the co-carrier of both doxorubicin (DOX) and the necrosis factor-related apoptosis-inducing ligand (pTRAIL). The LHRss/DOX/TRAIL construct has reduction-sensitive behavior and an enhanced endosomal escape ability to increase the cytotoxicity of DOX and the transfection efficiency. Further, the LHRss/DOX/TRAIL construct increased the accumulation of DOX and promoted the expression of pTRAIL, thus increasing cellular apoptosis by 83.7% in MCF-7/ADR cells. In addition, the in vivo biodistribution results showed that the LHRss/DOX/TRAIL construct could target tumors well. The in vivo anti-tumor effect study demonstrated that the LHRss/DOX/TRAIL construct inhibited tumor growth markedly, with a tumor inhibitory rate of 94.0%. The co-delivery system showed a significant synergistic anti-tumor effect. The LHRss/DOX/TRAIL construct may prove to be a promising co-delivery vector for the effective treatment of drug resistant breast cancer.

MicroRNA delivery system inhibits proliferation of androgen-independent prostate cancer

Objective To prepare a microRNA(miRNA)delivery system using the branched polyethyleneimine(BPEI),linear polyethylenimine(LPEI)and polyamidoamine dendrimers(PAMAM)loaded with miRNA-15 aand miRNA-16-1,which can inhibit prostate cancer PC3 cell proliferation,and to examine the zeta potential,intracellular uptake,and the inhibition effect on PC3 cells of the three constructed nano-complexes.Methods Particle size analyzer was used to determine the size and potential of the three kinds of nano-complexes,and the miRNA affinity capability of them was determined by agarose gel electrophoresis retardation assay.The uptake efficiency of the nano-complexes by PC3 cells was examined by NC-miRNA labeled with FAM.CCK8 method was used to determine the inhibitory effect of the nano-complexes loaded with miRNA-15 a and miRNA-16-1against PC3 cells,and PCR was used to analyze their inhibitory effect on expression of Bcl-2,Cylin D1 and Wnt3agene in PC3 cells.Results BPEI,LPEI and PAMAM loaded with miRNA could form stable nano-complexes.When N/P=5,the intracellular uptake of BPEI/miRNA-FAM by PC3 cells was significantly higher than that of LPEI/miRNA-FAM and PAMAM/miRNA-FAM(P0.05).BPEI,LPEI and PAMAM could all carry miRNA-15 aand miRNA-16-1into PC3 cells and block Bcl-2,Cylin D1 and Wnt3aexpression in PC3 cells.Conclusion BPEI,LPEI and PAMAM loaded with miRNA-15 aand miRNA-16-1can suppress proliferation of prostate cancer PC3 cells and block Bcl-2,Cylin D1 and Wnt3aexpression.

Preparation of polyethylene glycol-modified polyarginine for gene delivery and in vitro evaluation

Objective To modify polyargine(PLR)with polyethylene glycol(PEG)and to observe the effect of PEG modification on PLR cytotoxicity and efficiency of PLR-mediated RNA interference.Methods 1 HNMR was used to characterize PLR-PEG and gel electrophoresis was adopted to determine the siRNA-packing capacity of PLR-PEG.The cytotoxicity of PLRPEG,cellular uptake and RNA interference efficiency of PLR-PEG/siRNA complexes were investigated using prostate cancer stem-like cells(RC-92a/hTERT).Results 1 HNMR results showed the successful synthesis of PLR-PEG.It was found that PEG modification decreased cytotoxicity of PLR and reduced cellular uptake of PLR/siRNA complexes,but the reduction of cellular uptake was limited when N/P was high.The modification also inhibited the efficiency of PLR-mediated RNA interference,but the influence of PEG modification was not notable within a certain range.Conclusion PEG-modified PLR may be a promising vector for gene therapy targeting prostate cancer stem cells.