Hypoxia/hepatoma dual specific suicide gene expression plasmid delivery using bio-reducible polymer for hepatocellular carcinoma therapy

Utilization of experimental design in the formulation and optimization of hyaluronic acid-based nanoemulgel loaded with a turmeric-curry leaf oil nanoemulsion for gingivitis

Numerous problems affect oral health, and intensive research is focused on essential oil-based nanoemulsions that might treat prevent or these problems. Nanoemulsions are delivery systems that enhance the distribution and solubility of lipid medications to targeted locations. Turmeric (Tur)- and curry leaf oil (CrO)-based nanoemulsions (CrO-Tur-self-nanoemulsifying drug delivery systems [SNEDDS]) were developed with the goal of improving oral health and preventing or treating gingivitis. They could be valuable because of their antibacterial and anti-inflammatory capabilities. CrO-Tur-SNEDDS formulations were produced using the response surface Box-Behnken design with different concentrations of CrO (120, 180, and 250 mg), Tur (20, 35, and 50 mg), and Smix 2:1 (400, 500, and 600 mg). The optimized formulation had a bacterial growth inhibition zone of up to 20 mm, droplet size of less than 140 nm, drug-loading efficiency of 93%, and IL-6 serum levels of between 950 ± 10 and 3000 ± 25 U/ml. The optimal formulation, which contained 240 mg of CrO, 42.5 mg of Tur, and 600 mg of Smix 2:1, was created using the acceptable design. Additionally, the best CrO-Tur-SNEDDS formulation was incorporated into a hyaluronic acid gel, and thereafter it had improved ex-vivo transbuccal permeability, sustained in-vitro release of Tur, and large bacterial growth suppression zones. The optimal formulation loaded into an emulgel had lower levels of IL-6 in the serum than the other formulations evaluated in rats. Therefore, this investigation showed that a CrO-Tur-SNEDDS could provide strong protection against gingivitis caused by microbial infections.

A multi-bioresponsive self-assembled nano drug delivery system based on hyaluronic acid and geraniol against liver cancer

Herein, a multi-bioresponsive self-assembled nano-drug delivery system (HSSG) was constructed by conjugating the anticancer drug Geraniol (GER) to hyaluronic acid (HA) via a disulfide bond. The HSSG NPs displayed a uniform spherical shape with an average diameter of ∼110 nm, maintained high stability, and realized controlled drug release in the tumor microenvironment (pH/glutathione/hyaluronidase). Results of fluorescence microscopy and flow cytometry verified that HSSG NPs were selectively uptaken by human hepatocellular carcinoma cell lines HepG2 and Huh7 via CD44 receptor-mediated internalization. Studies on H22 tumor-bearing mice demonstrate that HSSG NPs could effectively accumulate at the tumor site for a long period. In vitro and in vivo studies show that HSSG NPs significantly promoted the death of cancer cells while reducing the toxicity as compared to GER. Therefore, the HSSG NPs have great potential in the treatment of tumors.

Applications of tissue-specific and cancer-selective gene promoters for cancer diagnosis and therapy

Current treatment of solid tumors with standard of care chemotherapies, radiation therapy and/or immunotherapies are often limited by severe adverse toxic effects, resulting in a narrow therapeutic index. Cancer gene therapy represents a targeted approach that in principle could significantly reduce undesirable side effects in normal tissues while significantly inhibiting tumor growth and progression. To be effective, this strategy requires a clear understanding of the molecular biology of cancer development and evolution and developing biological vectors that can serve as vehicles to target cancer cells. The advent and fine tuning of omics technologies that permit the collective and spatial recognition of genes (genomics), mRNAs (transcriptomics), proteins (proteomics), metabolites (metabolomics), epiomics (epigenomics, epitranscriptomics, and epiproteomics), and their interactomics in defined complex biological samples provide a roadmap for identifying crucial targets of relevance to the cancer paradigm. Combining these strategies with identified genetic elements that control target gene expression uncovers significant opportunities for developing guided gene-based therapeutics for cancer. The purpose of this review is to overview the current state and potential limitations in developing gene promoter-directed targeted expression of key genes and highlights their potential applications in cancer gene therapy.

Cholangiocarcinoma: molecular imaging-guided radiofrequency hyperthermia-enhanced intratumoral herpes simplex virus thymidine kinase gene therapy

We investigated the feasibility of using radiofrequency hyperthermia (RFH) to enhance green fluorescent protein (GFP)/herpes simplex virus thymidine kinase (HSV-TK)/ganciclovir (GCV) gene therapy of cholangiocarcinoma. Cholangiocarcinoma cells and mice with cholangiocarcinoma were treated by (i) GFP/HSV-TK/plasmid combined with RFH at 42°C, followed by ganciclovir administration; (ii) HSV-TK alone; (iii) RFH alone; and (iv) saline. The therapeutic effects among different treatments were evaluated by bioluminescent optical imaging and ultrasound imaging. For the technical validation, GFP/HSV-TK/plasmid was intrabiliarily injected into pig common bile duct (CBD) walls using a needle-integrated balloon catheter with or without RFH enhancement. GFP gene expression was evaluated by optical imaging, which was correlated with histology. The results show that combination therapy of HSV-TK plus RFH significantly induced lower cell viabilities and decreased bioluminescence signals compared the other three groups, which were further confirmed by the tumor volume decrease with combination therapy, as measured by ultrasound imaging. Optical imaging of CBD tissues demonstrated an increased GFP expression in the group with RFH enhancement, compared that with non-RFH treatment. We concluded that intratumoral RFH can enhance the therapeutic effect of GFP/HSV-TK/plasmid on cholangiocarcinoma, which may open new avenues for effective treatment of this deadly disease.

Radiofrequency hyperthermia promotes the therapeutic effects on chemotherapeutic-resistant breast cancer when combined with heat shock protein promoter-controlled HSV-TK gene therapy: Toward imaging-guided interventional gene therapy

Objective

Gene therapy is a frontier in modern medicine. In the present study, we explored a new technique for the effective treatment of multidrug-resistant (MDR) breast cancer by combining fully the advantages of multidisciplinary fields, including image-guided minimally invasive interventional oncology, radiofrequency technology, and direct intratumoral gene therapy.

Results

Combination treatment with P_HSP-TK plus RFH resulted in significantly higher TK gene transfection/expression, as well as a lower cell proliferation rate and a higher cell apoptosis index, than those of control groups. In vivo validation experiments with MRI confirmed that combination therapy resulted in a significant reduction of relative tumor volume compared with those of control animals, which was supported by the results of histologic and apoptosis analyses.

Materials and methods

The heat shock protein promoter (P_HSP) was used to precisely control the overexpression of thymidine kinase (TK) (P_HSP-TK). Serial in vitro experiments were performed to confirm whether radiofrequency hyperthermia (RFH) could enhance P_HSP-TK transfection and expression in a MDR breast cancer cell line (MCF7/Adr). Serial in vivo experiments were then carried out to validate the feasibility of the new technique, termed interventional RFH-enhanced direct intratumoral P_HSP-TK gene therapy. The therapeutic effect of combination therapy was evaluated by MRI and confirmed by subsequent laboratory correlation.

Conclusions

This study has established “proof-of-principle” of a new technique, interventional RFH-enhanced local gene therapy for MDR breast cancer, which may open new avenues for the effective management of MDR breast cancers via the simultaneous integration of interventional oncology, RF technology, and direct intratumoral gene therapy.

Characterization of neural stem cells modified with hypoxia/neuron-specific VEGF expression system for spinal cord injury

Spinal cord injury (SCI) is an incurable disease causing an ischemic environment and functional defect, thus a new therapeutic approach is needed for SCI treatment. Vascular endothelial growth factor (VEGF) is a potent therapeutic gene to treat SCI via angiogenesis and neuroprotection, and both tissue-specific gene expression and high gene delivery efficiency are important for successful gene therapy. Here we design the hypoxia/neuron dual-specific gene expression system (pEpo-NSE) and efficient gene delivery platform can be achieved by the combination ex vivo gene therapy with erythropoietin (Epo) enhancer, neuron-specific enolase (NSE) promoter and neural stem cells (NSCs). An in vitro model, NSCs transfected with pEpo-NSE were consistently and selectively overexpressing therapeutic genes in response to neural differentiation and hypoxic conditions. Also, in SCI model, ex vivo gene therapy using pEpo-NSE system with NSCs significantly enhanced gene delivery efficiency compared with pEpo-NSE system gene therapy alone. However, microarray analysis reveals that introducing exogenous pEpo-NSE and VEGF triggers biological pathways in NSCs such as glycolysis and signaling pathways such as Ras and mitogen-activated protein kinase, leading to cell proliferation, differentiation and apoptosis. Collectively, it indicates that the pEpo-NSE gene expression system works stably in NSCs and ex vivo gene therapy using pEpo-NSE system with NSCs improves gene expression efficiency. However, exogenously introduced pEpo-NSE system has an influence on gene expression profiles in NSCs. Therefore, when we consider ex vivo gene therapy for SCI, the effects of changes in gene expression profiles in NSCs on safety should be investigated.

Nanoparticles for death‑induced gene therapy in cancer (Review)

Due to the high toxicity and side effects of the use of traditional chemotherapy in cancer, scientists are working on the development of alternative therapeutic technologies. An example of this is the use of death‑induced gene therapy. This therapy consists of the killing of tumor cells via transfection with plasmid DNA (pDNA) that contains a gene which produces a protein that results in the apoptosis of cancerous cells. The cell death is caused by the direct activation of apoptosis (apoptosis‑induced gene therapy) or by the protein toxic effects (toxin‑induced gene therapy). The introduction of pDNA into the tumor cells has been a challenge for the development of this therapy. The most recent implementation of gene vectors is the use of polymeric or inorganic nanoparticles, which have biological and physicochemical properties (shape, size, surface charge, water interaction and biodegradation rate) that allow them to carry the pDNA into the tumor cell. Furthermore, nanoparticles may be functionalized with specific molecules for the recognition of molecular markers on the surface of tumor cells. The binding between the nanoparticle and the tumor cell induces specific endocytosis, avoiding toxicity in healthy cells. Currently, there are no clinical protocols approved for the use of nanoparticles in death‑induced gene therapy. There are still various challenges in the design of the perfect transfection vector, however nanoparticles have been demonstrated to be a suitable candidate. This review describes the role of nanoparticles used for pDNA transfection and key aspects for their use in death‑induced gene therapy.

Hypoxia-inducible tumour-specific promoters as a dual-targeting transcriptional regulation system for cancer gene therapy

Transcriptional targeting is the best approach for specific gene therapy. Hypoxia is a common feature of the tumour microenvironment. Therefore, targeting gene expression in hypoxic cells by placing transgene under the control of a hypoxia-responsive promoter can be a good strategy for cancer-specific gene therapy. The hypoxia-inducible gene expression system has been investigated more in suicide gene therapy and it can also be of great help in knocking down cancer gene therapy with siRNAs. However, this system needs to be optimised to have maximum efficacy with minimum side effects in normal tissues. The combination of tissue-/tumour-specific promoters with HRE core sequences has been found to enhance the specificity and efficacy of this system. In this review, hypoxia-inducible gene expression system as well as gene therapy strategies targeting tumour hypoxia will be discussed. This review will also focus on hypoxia-inducible tumour-specific promoters as a dual-targeting transcriptional regulation systems developed for cancer-specific gene therapy.

The effect and mechanism of bufalin on regulating hepatocellular carcinoma cell invasion and metastasis via Wnt/β-catenin signaling pathway

Hepatocellular carcinoma (HCC) is a highly malignant tumor with an extremely poor prognosis. Our preliminary study indicated that bufalin could restrain the proliferation of human hepatoma BEL-7402 cells in a time- and dose-dependent manner. In the present study, the colony formation assay, the Transwell invasion assay, the western blot analysis and the immunofluorescence method were respectively used to investigate the effect and mechanism of bufalin against HCC cell invasion and metastasis. We found that: i) bufalin had significant inhibitory effect on the cell proliferation of BEL-7402 cells; ii) bufalin markedly inhibited the migration and invasion of BEL-7402 cells; iii) bufalin could suppress the phosphorylation of GSK-3β Ser9 site in BEL-7402 cells, decrease the expression of β-catenin, cyclin D1, metalloproteinases-7 (MMP-7) and cyclooxygenase-2 (COX-2) in the cytoplasm, and increase the expression of E-cadherin and β-catenin on the cell membrane; and iv) the expression of α-fetoprotein significantly decreased and the expression of albumin increased in BEL-7402 cells after bufalin was used. Our results indicate that: i) bufalin can regulate the expression of associated factors in Wnt/β-catenin signaling pathway of BEL-7402 cells through suppressing the phosphorylation of GSK-3β Ser9 site; ii) bufalin can strengthen intercellular E-cadherin/β-catenin complex to control epithelial-mesenchymal transition; and iii) bufalin can reverse the malignant phenotype and promote the differentiation and maturation by regulating the AFP and ALB expression in BEL-7402 cells. These are very important mechanisms of bufalin on the inhibition of the invasion and metastasis of HCC cells.

DNA Polymerases as targets for gene therapy of hepatocellular carcinoma

Background

Hepatocyte carcinoma (HCC) is one of the most common malignancies worldwide. Despite many achievements in diagnosis and treatment, HCC mortality remains high due to the malignant nature of the disease. Novel approaches, especially for targeted therapy, are being extensively explored. Gene therapy is ideal for such purpose for its specific expression of exogenous genes in HCC cells driven by tissue-specific promoter. However strategies based on correction of mutations or altered expressions of genes responsible for the development/progression of HCC have limitations because these aberrant molecules are not presented in all cancerous cells. In the current work, we adopted a novel strategy by targeting the DNA replication step which is essential for proliferation of every cancer cell.

Methods

A recombinant adenovirus with alpha fetoprotein (AFP) promoter-controlled expressions of artificial microRNAs targeting DNA polymerases α, δ, ε and recombinant active Caspase 3, namely Ad/AFP-Casp-AFP-amiR, was constructed.

Results

The artificial microRNAs could efficiently inhibit the expression of the target polymerases in AFP-positive HCC cells at both RNA and protein levels, and HCC cells treated with the recombinant virus Ad/AFP-Casp-AFP-amiR exhibited significant G0/1 phase arrest. The proliferation of HCC cells were significantly inhibited by Ad/AFP-Casp-AFP-amiR with increased apoptosis. On the contrary, the recombinant adenovirus Ad/AFP-Casp-AFP-amiR did not inhibit the expression of DNA polymerases α, δ or ε in AFP-negative human normal liver cell HL7702, and showed no effect on the cell cycle progression, proliferation or apoptosis.

Conclusions

Inhibition of DNA polymerases α, δ and ε by AFP promoter-driven artificial microRNAs may lead to effective growth arrest of AFP-positive HCC cells, which may represent a novel strategy for gene therapy by targeting the genes that are essential for the growth/proliferation of cancer cells, avoiding the limitations set by any of the individually altered gene.

Peptide micelle-mediated delivery of tissue-specific suicide gene and combined therapy with avastin in a glioblastoma model

Bevacizumab (Avastin) is an angiogenesis inhibitor used as a treatment for various cancers. In this study, the combination therapy of Avastin and glioblastoma-specific thymidine kinase gene [pEpo-NI2-SV-herpes simplex virus thymidine kinase(HSVtk)] was evaluated in a glioblastoma animal model. The R7L10 peptide was used as a gene carrier of pEpo-NI2-SV-HSVtk. Gel retardation assays confirmed that R7L10 formed stable complexes with pEpo-NI2-SV-HSVtk. R7L10 protected DNA from nuclease digestion. R7L10 had lower transfection efficiency than polyethylenimine (PEI; 25 kDa). However, the in vitro and in vivo toxicity assays showed that R7L10 had lower cytotoxicity than PEI, suggesting that R7L10 is safer than PEI. For the combination therapy, Avastin was injected intravenously and the pEpo-NI2-SV-HSVtk/R7L10 complexes were injected intratumorally in the glioblastoma animal model. Tumor growth was most effectively inhibited by the combination therapy of Avastin and the gene. The immunostaining results confirmed that the HSVtk genes were expressed in the groups with the pEpo-NI2-SV-HSVtk/R7L10 complex. The terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed a higher level of apoptotic cells in the combination group than the pEpo-NI2-SV-HSVtk/R7L10 complex or Avastin group. In conclusion, the combination of Avastin and the glioblastoma-specific HSVtk gene has a higher antitumor effect than single therapy of Avastin or HSVtk after intratumoral administration in glioblastoma animal model.

Noninvasive theranostic imaging of HSV-TK/GCV suicide gene therapy in liver cancer by folate-targeted quantum dot-based liposomes

We have successfully developed folate-targeting liposomes for effective and safe HSV-TK suicide gene theranostics.

Luciferase gene-loaded CS-Qdots as self-illuminating probes for specific hepatoma imaging

Luciferase gene-loaded chitosan encapsulated quantum dots (CS-Qdots) can act as wavelength-tunable self-illuminating probes thus holding potential for improved tumor optical molecular imaging.

Gene therapy and imaging in preclinical and clinical oncology: recent developments in therapy and theranostics

In the case of disseminated cancer, current treatment options reach their limit. Gene theranostics emerge as an innovative route in the treatment and diagnosis of cancer and might pave the way towards development of an efficacious treatment of currently incurable cancer. Various gene vectors have been developed to realize tumor-specific nucleic acid delivery and are considered crucial for the successful application of cancer gene therapy. By adding reporter genes and imaging agents, these systems gain an additional diagnostic function, thereby advancing the theranostic paradigm into cancer gene therapy. Numerous preclinical studies have demonstrated the feasibility of combined tumor gene therapy and diagnostic imaging, and clinical trials in human and veterinary oncology have been executed with partly encouraging results.

Magnetic nanoparticles for targeted therapeutic gene delivery and magnetic-inducing heating on hepatoma

Gene therapy holds great promise for treating cancers, but their clinical applications are being hampered due to uncontrolled gene delivery and expression. To develop a targeted, safe and efficient tumor therapy system, we constructed a tissue-specific suicide gene delivery system by using magnetic nanoparticles (MNPs) as carriers for the combination of gene therapy and hyperthermia on hepatoma. The suicide gene was hepatoma-targeted and hypoxia-enhanced, and the MNPs possessed the ability to elevate temperature to the effective range for tumor hyperthermia as imposed on an alternating magnetic field (AMF). The tumoricidal effects of targeted gene therapy associated with hyperthermia were evaluated in vitro and in vivo. The experiment demonstrated that hyperthermia combined with a targeted gene therapy system proffer an effective tool for tumor therapy with high selectivity and the synergistic effect of hepatoma suppression.

Tumor targeting RGD conjugated bio-reducible polymer for VEGF siRNA expressing plasmid delivery

Targeted delivery of therapeutic genes to the tumor site is critical for successful and safe cancer gene therapy. The arginine grafted bio-reducible poly (cystamine bisacrylamide-diaminohexane, CBA-DAH) polymer (ABP) conjugated poly (amido amine) (PAMAM), PAM-ABP (PA) was designed previously as an efficient gene delivery carrier. To achieve high efficacy in cancer selective delivery, we developed the tumor targeting bio-reducible polymer, PA-PEG1k-RGD, by conjugating cyclic RGDfC (RGD) peptides, which bind αvβ3/5 integrins, to the PAM-ABP using polyethylene glycol (PEG, 1 kDa) as a spacer. Physical characterization showed nanocomplex formation with bio-reducible properties between PA-PEG1k-RGD and plasmid DNA (pDNA). In transfection assays, PA-PEG1k-RGD showed significantly higher transfection efficiency in comparison with PAM-ABP or PA-PEG1k-RAD in αvβ3/5 positive MCF7 breast cancer and PANC-1 pancreatic cancer cells. The targeting ability of PA-PEG1k-RGD was further established using a competition assay. To confirm the therapeutic effect, the VEGF siRNA expressing plasmid was constructed and then delivered into cancer cells using PA-PEG1k-RGD. PA-PEG1k-RGD showed 20-59% higher cellular uptake rate into MCF7 and PANC-1 than that of non-targeted polymers. In addition, MCF7 and PANC-1 cancer cells transfected with PA-PEG1k-RGD/pshVEGF complexes had significantly decreased VEGF gene expression (51-71%) and cancer cell viability (35-43%) compared with control. These results demonstrate that a tumor targeting bio-reducible polymer with an anti-angiogenic therapeutic gene could be used for efficient and safe cancer gene therapy.

Bioreducible polymers for therapeutic gene delivery

Most currently available cationic polymers have significant acute toxicity concerns such as cellular toxicity, aggregation of erythrocytes, and entrapment in the lung capillary bed, largely due to their poor biocompatibility and non-degradability under physiological conditions. To develop more intelligent polymers, disulfide bonds are introduced in the design of biodegradable polymers. Herein, the sustained innovations of biomimetic nano-sized constructs with bioreducible poly(disulfide amine)s demonstrate a viable clinical tool for the treatment of cardiovascular disease, anemia, diabetes, and cancer.

Suicide Gene Therapy for Cancer - Current Strategies

Current cancer treatments may create profound iatrogenic outcomes. The adverse effects of these treatments still remain, as the serious problems that practicing physicians have to cope with in clinical practice. Although, non-specific cytotoxic agents constitute an effective treatment modality against cancer cells, they also tend to kill normal, quickly dividing cells. On the other hand, therapies targeting the genome of the tumors are both under investigation, and some others are already streamlined to clinical practice. Several approaches have been investigated in order to find a treatment targeting the cancer cells, while not affecting the normal cells. Suicide gene therapy is a therapeutic strategy, in which cell suicide inducing transgenes are introduced into cancer cells. The two major suicide gene therapeutic strategies currently pursued are: cytosine deaminase/5-fluorocytosine and the herpes simplex virus/ganciclovir. The novel strategies include silencing gene expression, expression of intracellular antibodies blocking cells' vital pathways, and transgenic expression of caspases and DNases. We analyze various elements of cancer cells' suicide inducing strategies including: targets, vectors, and mechanisms. These strategies have been extensively investigated in various types of cancers, while exploring multiple delivery routes including viruses, non-viral vectors, liposomes, nanoparticles, and stem cells. We discuss various stages of streamlining of the suicide gene therapy into clinical oncology as applied to different types of cancer. Moreover, suicide gene therapy is in the center of attention as a strategy preventing cancer from developing in patients participating in the clinical trials of regenerative medicine. In oncology, these clinical trials are aimed at regenerating, with the aid of stem cells, of the patients' organs damaged by pathologic and/or iatrogenic factors. However, the stem cells carry the risk of neoplasmic transformation. We discuss cell suicide inducing strategies aimed at preventing stem cell-originated cancerogenesis.