Adenovirus-mediated p53 tumor suppressor gene therapy of osteosarcoma

The clinical outcome for osteosarcoma (OS) remains discouraging despite efforts to optimize treatment using conventional modalities including surgery, radiotherapy and chemotherapy. Novel therapeutic approaches based on our expanding understanding of the mechanisms of tumor cell killing have the potential to alter this situation. Tumor suppressor gene therapy aims to restore the function of a tumor suppressor gene lost or functionally inactivated in cancer cells. One such molecule, the p53 tumor suppressor gene plays a critical role in safeguarding the integrity of the genome and preventing tumorigenesis. Introduction of wild-type (wt) p53 into transformed cells has been shown to be lethal for most cancer cells in vitro, but clinical trials of p53 gene replacement have had limited success. Analysis of these clinical trials highlighted the insufficient efficacy of current vectors and low proapoptotic activity of wt p53 as a single agent in vivo. In this review, a contemporary summarization of the current status of adenovirus-mediated p53 gene therapy of OS is presented. Advancement in our understanding of p53 tumor suppressor activity, the molecular biology of chemoresistant OS, and recent advances in tumor targeting with adenoviral vectors are also addressed. Based on these parameters, prospects for future investigations are proposed.     

In vivo treatment of tumors using host-guest conjugated nanoparticles functionalized with doxorubicin and therapeutic gene pTRAIL

The combination of gene therapy and chemotherapy may increase the therapeutic efficacy in the treatment of patients. In this work, the anti-cancer drug Dox and therapeutic gene pTRAIL-loaded host−guest co-delivery system was assayed for the possibility of in vivo synergistically treating tumors. The introduced Dox could act as an auxiliary component to human tumor necrosis factor-related apoptosis-inducing ligand-encoding plasmid gene pTRAIL. Such delivery system possessed the good ability of in vivo retention of chemotherapeutic drugs, achieved good therapeutic effects in the inhibition of tumor growth and significantly prolonged the survival time of tumor-bearing mice. With the efficient ability to co-deliver drug and gene, such host−guest assembly should have great potential applications in cancer therapy.     

Dual tumor targeting with pH-sensitive and bioreducible polymer-complexed oncolytic adenovirus

Oncolytic adenoviruses (Ads) have shown great promise in cancer gene therapy but their efficacy has been compromised by potent immunological, biochemical, and specific tumor-targeting limitations. To take full advantage of the innate cancer-specific killing potency of oncolytic Ads but also exploit the subtleties of the tumor microenvironment, we have generated a pH-sensitive and bio-reducible polymer (PPCBA)-coated oncolytic Ad. Ad-PPCBA complexes showed higher cellular uptake at pH 6.0 than pH 7.4 in both high and low coxsackie and adenovirus receptor-(CAR)-expressing cells, thereby demonstrating Ad-PPCBA's ability to target the low pH hypoxic tumor microenvironment and overcome CAR dependence for target cell uptake. Endocytic mechanism studies indicated that Ad-PPCBA internalization is mediated by macropinocytosis instead of the CAR-dependent endocytic pathway that internalizes naked Ad. VEGF-specific shRNA-expressing oncolytic Ad complexed with PPCBA (RdB/shVEGF-PPCBA) elicited much more potent suppression of U87 human brain cancer cell VEGF gene expression in vitro, and human breast cancer MCF7 cell/Matrigel plug vascularization in a mouse model, when cancer cells had been previously infected at pH 6.0 versus pH 7.4. Moreover, intratumorally and intravenously injected RdB/shVEGF-PPCBA nanocomplexes elicited significantly higher therapeutic efficacy than naked virus in U87-tumor mouse xenograft models, reducing IL-6, ALT, and AST serum levels. These data demonstrated PPCBA's biocompatibility and capability to shield the Ad surface to prevent innate immune response against Ad after both intratumoral and systemic administration. Taken together, these results demonstrate that smart, tumor-specific, oncolytic Ad-PPCBA complexes can be exploited to treat both primary and metastatic tumors.     

Maltosylated polyethylenimine-based triple nanocomplexes of human papillomavirus 16L1 protein and DNA as a vaccine co-delivery system

To improve vaccine delivery, we herein designed a co-delivery system using a protein antigen and its encoding plasmid linked in nanocomplexes via maltosylated PEI (mPEI). Cationic mPEI was electrostatically complexed to a plasmid encoding the human papillomavirus (HPV) type 16L1 protein (pHPV16L1), and further complexed to a maltose binding protein (MBP)-fused human papillomavirus type 16L1 fusion protein (HPV16L1-MBP). The HPV16L1-MBP/mPEI/pHPV16L1 complexes were characterized by gel-retardation properties, zeta potentials and sizes. The intracellular co-delivery of protein and plasmid DNA vaccines was significantly higher for mPEI-based triple nanocomplexes than for a simple physical mixture of the proteins and DNA. Moreover, the cellular delivery of plasmid DNA using mPEI-based triple nanocomplexes resulted in higher expression levels comparable to those obtained using dual complexes of mPEI and the plasmid DNA. In vivo, co-immunization of mice with HPV16L1-MBP/mPEI/pHPV16L1 nanocomplexes triggered the highest levels of humoral immune responses among various vaccination groups. Moreover, the mPEI-based nanocomplexes significantly enhanced the number of interferon-γ producing CD8(+) T cells compared with the use of mixed proteins and plasmid DNA. These results suggest that the effective cellular co-delivery of MBP-fused antigen proteins and plasmid DNA using maltosylated PEI-based triple nanocomplexes could enhance the immunogenicity of HPV16L1 vaccines.     

Multifunctional receptor-targeted nanocomplexes for magnetic resonance imaging and transfection of tumours

The efficient targeted delivery of nucleic acids in?vivo provides some of the greatest challenges to the development of genetic therapies. We aim to develop nanocomplex formulations that achieve targeted transfection of neuroblastoma tumours that can be monitored simultaneously by MRI. Here, we have compared nanocomplexes comprising self-assembling mixtures of liposomes, plasmid DNA and one of three different peptide ligands derived from ApoE, neurotensin and tetanus toxin for targeted transfection in?vitro and in?vivo. Neurotensin-targeted nanocomplexes produced the highest levels of transfection and showed a 4.7-fold increase in transfected luciferase expression over non-targeted nanocomplexes in Neuro-2A cells. Transfection of subcutaneous Neuro-2A tumours in?vivo with neurotensin-targeted nanocomplexes produced a 9.3-fold increase in gene expression over non-targeted controls. Confocal microscopy analysis elucidated the time course of DNA delivery with fluorescently labelled nanocomplex formulations in cells. It was confirmed that addition of a gadolinium lipid conjugate contrast agent allowed real time in?vivo monitoring of nanocomplex localisation in tumours by MRI, which was maintained for at least 24?h. The peptide-targeted nanocomplexes developed here allow for the specific enhancement of targeted gene therapy both in?vitro and in?vivo, whilst allowing real time monitoring of delivery with MRI.     

A chitosan-graft-PEI-candesartan conjugate for targeted co-delivery of drug and gene in anti-angiogenesis cancer therapy

A multifunctional copolymer–anticancer conjugate chitosan-graft-polyethyleneimine-candesartan (CPC) containing low molecular weight chitosan (CS) backbone and polyethyleneimine (PEI) arms with candesartan (CD) conjugated via an amide bond was fabricated as a targeted co-delivery nanovector of drug and gene for potential cancer therapy. Here, CD was utilized to specifically bind to overexpressed angiotensin II type 1 receptor (AT₁R) of tumor cells, strengthen endosomal buffering capacity of CPC and suppress tumor angiogenesis. The self-assembled CPC/pDNA complexes exhibited desirable and homogenous particle size, moderate positive charges, superior stability, and efficient release of drug and gene in vitro. Flow cytometry and confocal laser scanning microscopy analyses confirmed that CD-targeted function and CD-enhanced buffering capacity induced high transfection, specific cellular uptake and efficient intracellular delivery of CPC/pDNA complexes in AT₁R-overexpressed PANC-1 cells. In addition, CPC/wt-p53 complexes co-delivering CD and wild type p53 (wt-p53) gene achieved synergistic angiogenesis suppression by more effectively downregulating the expression of vascular endothelial growth factor (VEGF) mRNA and protein via different pathways in vitro, as compared to mono-delivery and mixed-delivery systems. In vivo investigation on nude mice bearing PANC-1 tumor xenografts revealed that CPC/wt-p53 complexes possessed high tumor-targeting capacity and strong anti-tumor activity. Additional analysis of microvessel density (MVD) demonstrated that CPC/wt-p53 complexes significantly inhibited tumor-associated angiogenesis. These findings suggested that CPC could be an ideal tumor-targeting nanovector for simultaneous transfer of drug and gene, and a multifunctional CPC/wt-p53 co-delivery system with tumor-specific targetability, enhanced endosomal buffering capacity and synergistic anti-angiogenesis efficacy might be a new promising strategy for effective tumor therapy.     

脂质体介导的p53基因对肝癌细胞生长的抑制作用

目的 观察外源野生型ｐ５３基因在肝癌基因治疗方面的可行性。方法 将载有人野生型ｐ５３－ｃＤＮＡ的真核表达质粒ｐ５３－ｐｃＤＮＡ３,用阳离子脂质体介导转染人肝癌细胞系ＨｅｐＧ２,用流式细胞仪检测ｐ５３－ｐｃＤＮＡ３对ＨｅｐＧ２细胞生长的影响。结果 通过观察细胞生长曲线与流式细胞仪检测细胞周期和细胞的凋亡指数发现,ＨｅｐＧ２细胞生长受到明显的抑制。结论 脂质体介导的ｐ５３基因可在Ｈ细胞中表达,且明显抑     

p53基因与顺铂联合作用对人卵巢癌细胞的杀伤效果

目的 :探讨外源性p5 3基因转染对人卵巢癌细胞系SKOV 3的生物学行为影响及与顺铂联合作用后对人卵巢癌细胞的杀伤效果。方法 :用脂质体介导的转染技术 ,将p5 3基因的真核细胞表达载体 (PcDNA p5 3)导入不表达p5 3的人卵巢癌SKOV 3细胞中 ,经G4 18筛选 ,Northernblot及Westernblot鉴定后 ,观察其对细胞生物学行为的影响及与顺铂联合作用后对细胞集落形成的影响。结果 :转染后获得稳定表达p5 3的转染克隆。外源性p5 3基因的表达明显抑制了卵巢癌细胞的生长及集落形成能力 ,使细胞阻滞于G1 期 ,并增加了卵巢癌细胞对顺铂的敏感性。结论 :外源性野生型p5 3基因能抑制卵巢癌细胞的生长 ,与顺铂联合作用后增强了对人卵巢癌细胞的杀伤效果。     

Use of macrophages to deliver therapeutic and imaging contrast agents to tumors

Drug targeting to tumors with limited toxicity and enhanced efficacy of drug is one of the important goals for cancer treatment pharmaceutics. Monocytes/macrophages are able to migrate to tumor sites across the blood barriers by acting as Trojan horses carrying drug cargoes. Taking this advantage, we have intended to develop an efficient administration system using a biologically active carrier of mouse peritoneal macrophage bearing liposomal doxorubicin (macrophage-LP-Dox). We expect that this system could improve the cancer therapeutic efficacy through deeper penetration into tumor even hypoxic region behind tumor blood vessel. We first confirmed that macrophages containing iron oxides could migrate and infiltrate into tumors effectively by MR imaging. Next, we showed that doxorubicin (Dox) encapsulated with liposomes (LP-Dox) was successfully loaded into macrophages, in which the biological activity of macrophage and cytotoxicity of Dox against tumor cells were well preserved. Delivery of Dox into tumor tissue by systemic administration of macrophage-LP-Dox was verified in both subcutaneous and metastasis xenograft tumor models. Importantly, the effective inhibition of in vivo tumor growth was proved with this system. Our results provide the feasibility of macrophages-LP-drug as an active biocarrier for the enhancement of therapeutic effects in cancer treatment and open new perspectives for the active delivery of drugs.     

Adenoviral-mediated gene therapy with Ad5CMVp53 and Ad5CMVp21 in combination with standard therapies in human breast cancer cell lines

Our objective was to determine the efficacy of adenoviral-mediated gene therapy with wild-type p53 or p21 in human breast cancer cells and investigate interactions with radiation and chemotherapy. Two human breast cancer cell lines, MDA-MB-231 and MDA-MB-435, both with p53 mutations, were transduced with adenoviral vectors containing wild-type p53 (Ad5CMV-p53) or p21/WAF1/Cip1 (Ad5CMV-p21), and the effects on growth were determined. Infection was combined with low-dose (1.4 - 3.7 Gy) irradiation to see if this would improve transduction efficiency and enhance numbers of cells killed. Transduction with either vector resulted in expression of p21WAF1/cip1 and growth inhibition, although Ad5CMV-p53 transduction produced greater growth inhibition than did Ad5CMV-p21. The cell lines differed in sensitivity to the vectors. The Ad5CMV-p53 vector in a multiplicity of infection (MOI) of 125 resulted in 50% to 80% inhibition of MDA-MB-231, while MOI 250 of the same vector resulted in 27% inhibition of MDA-MB-435. Infection with Ad5CMV-p21 produced modest growth inhibition in both cell lines (< or = 40% at MOI 200), although protein expression was detected at lower viral doses. Low dose gamma-irradiation (1.4 to 3.7 Gy) was used to try and improve the rate of gene transfer. Modest increases in transduction efficiency and duration of expression of a vector containing beta-galactosidase occurred in irradiated breast cancer cells. Radiation 24 hr before transduction with Ad5CMV-p53 increased the proportions of apoptotic MDA-MB-231 cells. The cells transduced with Ad5CMV-p21 were arrested in G1, yet when they were irradiated before adenoviral transduction, the overexpression of p21 protected the cells from the cytotoxic effects of the radiation. Clonogenic assays showed that Ad5CMV-p21 reduced the sensitivity of MDA-MB-231 to VP-16 and paclitaxel. Combining these drugs with Ad5CMV-p53 did not consistently or significantly decrease clonogenic survival.     

Role of Cancer Stem-like Cells in the Process of Invasion and Mesenchymal Transformation by a Reconstituted Triple-negative Breast Cancer Cell Population Resistant to p53-induced Apoptosis

We investigated the role of cancer stem cells (CSCs) in a population of triple-negative breast cancer (TNBC) cells that are resistant to apoptosis. A human breast cancer cell population capable of inducing p53 expression with doxycycline (Dox) was created and used as an untreated control (UT). After the addition of Dox to UT for 5 days, the cell population reconstituted with cells showing resistance to apoptosis was named RE. Fluorescence-activated cell sorting (FACS) and immunostaining revealed that after the addition of Dox, the ratio of cells in the S and G2/M phases decreased in UT as apoptosis proceeded, but did not markedly change in apoptosis-resistant RE. CSC-like cells in RE exhibited a cell morphology with a larger ratio of the major/minor axis than UT. FACS showed that RE had a higher proportion of CSC-like cells and contained more CD44⁺CD24⁻ mesenchymal CSCs than ALDH1A3⁺ epithelial-like CSCs. In a Matrigel invasion assay, UT was more likely to form a three-dimensional cell population, whereas RE exhibited a planar population, higher migration ability, and the up-regulated expression of epithelial-mesenchymal transition-related genes. These results provide insights into the mechanisms by which TNBC cells acquire treatment resistance at the time of recurrence.     

乳腺癌中p53基因丢失与p53 mRNA高表达相关性研究

为探讨乳腺癌组织中ｐ５３基因丢失与ｐ５３ ｍＲＮＡ表达的相关性，应用Ｓｏｕｔｈｅｒｎ杂交及反转录－定量ＰＣＲ技术对４７例乳腺癌组织进行了检测。结果发现：ｐ５３基因杂合性缺失率为３４．０％；在乳腺正常腺体中有中度ｐ５３ＲＮＡ表达，面 肿瘤组织中有４０．０％，患者伴ｐ５３ ｍＲＮＡ高表达。ｐ５３基因与ｐ５３ ｍＲＮＡ高表达之间呈显著性相关。     

人野生型p53 cDNA的克隆、表达和意义

目的：为探讨肿瘤细胞ｗｔ ｐ５３蛋白功能失活机制的研究,检测肿瘤患者血清抗ｐ５３抗体辅助临床诊断提供人ｗｔ ｐ５３蛋白。方法 将人ｗｔ ｐ５３基因ｃＤＮＡ片段插入到大肠杆菌表达载体ｐＱＥ－３０中,得到重组表达质粒ｐＱＥ３０－ｐ５３,用ｐＱＥ３０－ｐ５３重组质粒转化大肠杆菌Ｍ１５细胞,转化菌落经ＰＣＲ扩增和ＢａｍＨⅠ、Ｘｂａ Ｉ酶切证实ｐ５３基因插入。ＩＰＴＧ诱导大肠杆菌表达ｗｔ ｐ５３蛋白,通过Ｎ     

p53 mediated apoptosis by reduction sensitive shielding ternary complexes based on disulfide linked PEI ternary complexes

Reduction-sensitive hyaluronic acid derivatives (HA–SS–COOH) were shielded on the DNA/polyethylenimine (PEI) to construct ternary complexes (DNA/PEI/HA–SS–COOH, DPS ternary complexes) with efficient gene transfection. Details studied were conducted to investigation of factors influencing transfection efficiency, including the gene compression by fluorescence resonance energy transfer (FRET) spectrum and the intracellular fate of fluorescent labeled complexes by the confocal laser scanning microscope (CLSM). In the FRET study, DPS complexes were found to enhance condensation of DNA in preparation, while timely loosen gene under exposure to reductive reagent. Similar cellular uptake levels were observed for the designed reduction sensitive complexes and the stable one (DNA/PEI/HA, DPH ternary complexes), but the intracellular process was strikingly different for the two types of complexes. Only DPS showed obvious desired intracellular deshielding and endosomal escape, which contributed to highly efficient gene delivery. After loading with p53 plasmid, DPS complexes achieved significantly up-regulated p53 tumor suppressor gene expression at both mRNA and protein levels, as revealed by quantitative polymerase chain reaction (qPCR) and western blot investigations. Transgene induced apoptosis was evaluated by propidium iodide staining and flow cytometry analysis of cell cycle. Tumor cells transfected by DPS complexes containing p53 gene displayed almost 50% higher suppression in proliferation compared to those untreated cells, accompanied with a 46% elevation in the number of cells at sub-G1 phase and remarkable p53 dependent cell cycle perturbations prior to apoptosis. These results demonstrated that targeted delivery of p53 gene via reduction-sensitive DPS ternary complexes enabled up-regulated cellular p53 mRNA level through the exogenous p53 gene, inducing a significant p53-dependent anti-proliferative effect on tumor cells, which could be effective means of cancer treatment.     

Multifunctional PEG-GO/CuS nanocomposites for near-infrared chemo-photothermal therapy

The synergistic therapy, the combination of photothermal therapy and chemotherapy, has become a potential treatment in the battles with cancer. Here, we developed a synergistic therapy tool that based on CuS nanoparticles-decorated graphene oxide functionalized with polyethylene glycol (PEG-GO/CuS) for cervical cancer treatment. The as-synthesized PEG-GO/CuS nanocomposites with excellent biocompatibility was revealed to have high storage capacity for anticancer drug of doxorubicin (Dox) and high photothermal conversion efficiency, and were effectively employed for the ablation of tumor. In addition, the therapeutic efficacy of Dox-loaded PEG-GO/CuS (PEG-GO/CuS/Dox) nanocomposites was evaluated in vitro and in vivo for cervical cancer therapy. In vitro cell cytotoxicity tests of PEG-GO/CuS/Dox demonstrate about 1.3 and 2.7-fold toxicity than PEG-GO/CuS and free Dox under 5 min irradiation with NIR laser at 1.0 W/cm², owing to both PEG-GO/CuS-mediated photothermal ablation and cytotoxicity of light-triggered Dox release. In mouse models, mouse cervical tumor growth was found to be significantly inhibited by the chemo-photothermal effect of PEG-GO/CuS/Dox nanocomposites, resulting in effective tumor reduction. Overall, compared with chemotherapy or photothermal therapy alone, the combined treatment demonstrates better therapeutic efficacy of cancer in vitro and in vivo. These findings highlight the promise of the highly versatile multifunctional nanoparticles in biomedical application.     

P53-binding protein 1: a new player for tumorigenesis and a new target for breast cancer treatment

Breast cancer remains the most common and fatal cancer in women and has been recognized as a genetic disease. Recently, accumulating evidences have showed that p53-binding protein 1 (53BP1) plays an important role in DNA double-strand breaks (DSBs) repair induced by radiation. In vitro experiments have indicated its interaction with many other genes or proteins for tumor suppression or tumorigenesis via pathways associated with DNA repair, cell-cycle control, apoptosis and cell senescence. In vivo studies also showed suppressive effect of 53BP1 on tumor initiation and progression. Therefore, we hypothesize that 53BP1 has a profound effect on suppressing breast cancer as a tumor suppressor and will be an important new biomarker for breast cancer prognosis. Furthermore, 53BP1 gene therapy will be a potential therapeutic strategy for breast cancer.     

Suppression of UV-induced mutations by wild-type p53 protein in human osteosarcoma cells

We have examined whether the tumour suppressor p53 protein suppressedUV-induced mutations in the hypoxathine-guanine phosphoribosyltransferase (HPRT) gene and in the supF gene of the shuttlevector plasmid pMY189. We used human osteosarcoma Saos-LP12cells, in which wild type (wt) p53 protein was induced by treatmentwith isopopyl-(ß-D-thiogalactopyranoside. The inductionof wt p53 protein suppressed UV-induced mutations but not spontaneousmutations in the HPRT gene. The frequency of UV-induced mutationsinduced by UV-irradiation of the plasmid was also significantlylower in cells with induced wt p53 protein than in the uninducedcells. In addition, we found that frequency of G : C to A :T transition mutations which occurred at the 3' base pair ofdipyrimidine sites were significantly lower in the cells withinduced wt p53 protein than in the uninduced cells. These findingssuggestthat wt p53 protein may play roles in modulating DNArepair pathway, resulting in the suppression of UV-induced mutations. ¹To whom correspondence should be addressed