Antitumor activity of combined endostatin and thymidine kinase gene therapy in C6 glioma models

Suicide Gene Delivery System Mediated by Ultrasound-Targeted Microbubble Destruction: A Promising Strategy for Cancer Therapy

The treatment of malignant tumors has always been one of the challenges that have plagued researchers and clinicians. The ideal status in cancer treatment is to eliminate tumor cells while avoiding damage to normal tissues. Different approaches have been investigated to achieve such a goal, and suicide gene therapy has emerged as a novel mode of cancer treatment. This approach involves the delivery of genes encoding enzymes that activate non-toxic prodrugs into cytotoxic metabolites that cause the death of transfected cancer cells. Despite promising results obtained both in vitro and in vivo, this innovative approach has long been stalled in the clinic due to the lack of a suitable delivery system to introduce the suicide gene into cancer cells. Ultrasound-targeted microbubble destruction (UTMD) represents a valuable non-viral vector system for site-specific and noninvasive gene therapy. Ultrasound promotes intracellular uptake of therapeutic agents by increasing vascular and cell membrane permeability, especially in the presence of microbubbles. In this scenario, the true potential of suicide genes can be translated into clinically valuable treatments for patients. This review provides background information on suicide gene therapy and UTMD technology, summarizes the current state of knowledge about UTMD-mediated suicide gene delivery in cancer treatment, and presents an outlook on its future development.

Cytochalasin B-induced membrane vesicles from human mesenchymal stem cells overexpressing TRAIL, PTEN and IFN-β1 can kill carcinoma cancer cells

Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) are of interest as a new vector for the delivery of therapeutic agents into the tumor microenvironment. Cell-free EV-based therapy has a number of advantages over cell-based therapy, since the use of EVs allows avoiding potential undesirable transformation associated with MSCs. MSC-derived EVs can transfer natural proteins with immunomodulatory or antitumor properties. The aim of this study was to produce vesicles from mesenchymal stem cells with simultaneous overexpression of TRAIL, PTEN and IFN-β1 and analyze its antitumor and immunomodulatory properties. In this work, a stable line of human adipose tissue-derived mesenchymal stem cells (hADSCs) with simultaneous overexpression of TRAIL, PTEN and IFN-β1 was produced. To obtain this cell line hADSCs were genetically modified with a genetic multicistronic cassette encoding TRAIL, PTEN, and IFN-β1 genes separated with a self-cleaving P2A peptide nucleotide sequence. Membrane vesicles (CIMVs) were obtained from genetically modified hADSCs using cytochalasin B treatment. Antitumor and immunomodulatory properties of the CIMVs were analyzed in vitro. It was shown that CIMVs isolated from genetically modified hADSCs overexpressing TRAIL, PTEN and IFN-β1 genes are able to activate human immune cells and induce apoptosis in various types of carcinomas in vitro. Thus, the immunomodulatory and antitumor properties of CIMVs were shown. However, further studies on animal models in vivo are required.

Current Developments in Targeted Drug Delivery Systems for Glioma

BACKGROUND

Glioma is one of the most commonly observed tumours, representing about 75% of brain tumours in the adult population. Generally, glioma treatment includes surgical resection followed by radiotherapy and chemotherapy. The current chemotherapy for glioma involves the use of temozolomide, doxorubicin, monoclonal antibodies, etc. however, the clinical outcomes in patients are not satisfactory. Primarily, the blood-brain barrier hinders these drugs from reaching the target leading to the recurrence of glioma post-surgery. In addition, these drugs are not target-specific and affect the healthy cells of the body. Therefore, glioma-targeted drug delivery is essential to reduce the rate of recurrence and treat the condition with more reliable alternatives.

METHODS

A literature search was conducted to understand glioma pathophysiology, its current therapeutic approaches for targeted delivery using databases like Pub Med, Web of Science, Scopus, and Google Scholar, etc. Results: This review gives an insight to challenges associated with current treatments, factors influencing drug delivery in glioma, and recent advancements in targeted drug delivery.

CONCLUSION

The promising results could be seen with nanotechnology-based approaches, like polymeric, lipidbased, and hybrid nanoparticles in the treatment of glioma. Biotechnological developments, such as carrier peptides and gene therapy, are future prospects in glioma therapy. Therefore, these targeted delivery systems will be beneficial in clinical practices for glioma treatment.

rAAV9-UPII-TK-EGFP can precisely transduce a suicide gene and inhibit the growth of bladder tumors

Bladder cancer is a common and widespread cancer of the human urinary system, and its incidence is increasing. Gene therapy is a promising treatment of bladder cancer. In our study, a recombinant adeno-associated virus (rAAV9-UPII-TK-EGFP) driven by a UPII promoter was constructed. The efficacy and safety of infection of bladder cells was tested in vivo and in vitro. The ability of rAAV9-UPII-TK-EGFP to penetrate the glycosaminoglycan (GAG) layer on the surface of bladder cells and to transduce the bladder cells in vivo was very high. Additionally, we confirmed that the TK/GCV system has a powerful cytotoxic effect on bladder tumor cells in vitro and in vivo. Thus, our data indicate that rAAV9-UPII-TK-EGFP is a precise gene drug delivery system for the treatment of bladder cancer, and the TK/GCV therapeutic strategy has a powerful antitumor effect. These findings can be widely used in clinical and scientific studies.

XCHD Inhibits C6 Cell Growth Primarily via the p53/Caspase Pathway

The effects of XCHD on the proliferation of C6 cells and on factors associated with the microRNA-34a (miR-34a)/p53/caspase-3 signaling pathway in vitro were investigated. Methods. XCHD was purchased too much to complete the study. CCK-8 assay was used to measure the XCHD concentration, and qPCR was used to quantify miR-34a expression at the mRNA level. Apoptosis was assessed using TUNEL. Western blots were used to determine the p53, caspase-3, caspase-8, and Bcl-2 expression levels. Results. The optimal XCHD concentration and time effect for C6 cells were observed after 36 h of exposure to a concentration of 100 µg/ml XCHD. miR-34a expression increased 8 and 12 h after the addition of XCHD. The presence of XCHD decreased Bcl-2 expression but increased p53, cleaved caspase-3, Bax, and caspase-8 expression. When p53 was inhibited, miR-34a expression was unaffected by the addition of XCHD, Bcl-2 expression was low, and cleaved caspase-3, Bax, and caspase-8 expression increased. The inhibition of p53 promoted C6 cell growth when compared with C6 cells exposed to XCHD and with no inhibition of p53. Conclusions. XCHD inhibits C6 cell growth which was influenced by the p53/caspase pathway.

MiR-210-3p Inhibits Proliferation and Migration of C6 Cells by Targeting Iscu

Glioma is the most common primary brain tumor and the most malignant type of glioma is glioblastoma with the character of high mortality, high recurrence rate and poor prognosis. MicroRNAs act as an important component in glioma development and thus may be a potential target for the treatment of glioma. There were some researches indicated that miR-210-3p played a role in glioma development, but if it can inhibit glioma growth, as well as the underlying mechanism, is still uncertain. In the present study, we investigated the effects of miR-210-3p and its potential target gene Iscu on glioma (C6) cells proliferation and migration in vitro as well as the influence of miR-210-3p on glioma growth in vivo. The results showed that miR-210-3p inhibited the proliferation and migration of C6 cells by regulating the expression of its target gene Iscu in vitro. We also demonstrated that glioma growth was suppressed in immunodeficient mice when they were implanted with C6 cells overexpressing miR-210-3p. Our data indicated that miR-210-3p played an important role in the prevention of glioma growth by targeting Iscu and so miR-210-3p/Iscu axis might be a potential target for the treatment of glioma.

Detection of lentiviral suicide gene therapy in C6 rat glioma using hyperpolarised [1-13 C]pyruvate

Hyperpolarised [1-¹³ C]pyruvate MRI has shown promise in monitoring therapeutic efficacy in a number of cancers including glioma. In this study, we assessed the pyruvate response to the lentiviral suicide gene therapy of herpes simplex virus-1 thymidine kinase with the prodrug ganciclovir (HSV-TK/GCV) in C6 rat glioma and compared it with traditional MR therapy markers. Female Wistar rats were inoculated with 10⁶ C6 glioma cells. Treated animals received intratumoural lentiviral HSV-TK gene transfers on days 7 and 8 followed by 2-week GCV therapy starting on day 10. Animals were repeatedly imaged during therapy using volumetric MRI, diffusion and relaxation mapping, as well as metabolic [1-¹³ C]pyruvate MRS imaging. Survival (measured as time before animals reached a humane endpoint and were euthanised) was assessed up to day 30 posttherapy. HSV-TK/GCV gene therapy lengthened the median survival time from 12 to 25 days. This was accompanied by an apparent tumour growth arrest, but no changes in diffusion or relaxation parameters in treated animals. The metabolic response was more evident in the case-by-case analysis than in the group-level analysis. Treated animals also showed a 37 ± 15% decrease (P < 0.05, n = 5) in lactate-to-pyruvate ratio between therapy weeks, whereas a 44 ± 18% increase (P < 0.05, n = 6) was observed in control animals. Hyperpolarised [1-¹³ C]pyruvate MRI can offer complementary metabolic information to traditional MR methods to give a more comprehensive picture of the slowly developing gene therapy response. This may benefit the detection of the successful therapy response in patients.

Production and Application of Multicistronic Constructs for Various Human Disease Therapies

The development of multicistronic vectors has opened up new opportunities to address the fundamental issues of molecular and cellular biology related to the need for the simultaneous delivery and joint expression of several genes. To date, the examples of the successful use of multicistronic vectors have been described for the development of new methods of treatment of various human diseases, including cardiovascular, oncological, metabolic, autoimmune, and neurodegenerative disorders. The safety and effectiveness of the joint delivery of therapeutic genes in multicistronic vectors based on the internal ribosome entry site (IRES) and self-cleaving 2A peptides have been shown in both in vitro and in vivo experiments as well as in clinical trials. Co-expression of several genes in one vector has also been used to create animal models of various inherited diseases which are caused by mutations in several genes. Multicistronic vectors provide expression of all mutant genes, which allows the most complete mimicking disease pathogenesis. This review comprehensively discusses multicistronic vectors based on IRES nucleotide sequence and self-cleaving 2A peptides, including its features and possible application for the treatment and modeling of various human diseases.

Novel Semi-Replicative Retroviral Vector Mediated Double Suicide Gene Transfer Enhances Antitumor Effects in Patient-Derived Glioblastoma Models

As glioblastomas are mostly localized infiltrative lesions, gene therapy based on the retroviral replicating vector (RRV) system is considered an attractive strategy. Combinations of multiple suicide genes can circumvent the limitations associated with each gene, achieving direct and synergistic cytotoxic effects, along with bystander cell killing. In this study, we constructed a semi-and pseudotyped-RRV (sp-RRV) system harboring two suicide genes—herpes simplex virus type 1 thymidine kinase (TK) and yeast cytosine deaminase (CD)—to verify the dissemination and antitumor efficacy of our sp-RRV system (spRRVe-sEF1α-TK/sRRVgp-sEF1α-CD) in seven patient-derived glioblastoma stem-like cells (GSCs). Flow cytometry and high-content analysis revealed a wide range of transduction efficiency and good correlation between the delivery of therapeutic genes and susceptibility to the prodrugs ganciclovir and 5-fluorocytosine in patient-derived GSCs in vitro. Intra-tumoral delivery of spRRVe-sEF1α-TK/sRRVgp-sEF1α-CD, combined with prodrug treatment, synergistically inhibited cell proliferation and angiogenesis while increasing apoptosis and the depletion of tumor-associated macrophages in orthotopic glioblastoma xenografts. Genomic profiling of patient-derived GSCs revealed that the key genes preventing sp-RRV infection and transmission were associated with cell adhesion, migration, development, differentiation, and proliferation. This is the first report demonstrating that a novel sp-RRV-mediated TK/CD double suicide gene transfer system has high oncolytic power against extremely heterogeneous and treatment-refractory glioblastomas.

The effect of gene therapy on postoperative recurrence of small hepatocellular carcinoma (less than 5cm)

To observe the curative effect of surgery combined with gene therapy on small hepatocellular carcinoma. Seventy-seven patients with small hepatocellular carcinoma (diameter < 5 cm) underwent surgical resection. The tumor located at the edge of the liver was treated by local excision or irregular hepatectomy. The tumor in the center of the liver was resected by hepatic lobectomy in order to ensure at least a 2-cm safety margin. Fifty-four patients underwent gene therapy (gene group) one or two times before operation, whereas 23 patients underwent surgery alone (control group) selected by themselves. The injectable gene was made of ADV-TK (adenovirus containing thymidine kinase suicide gene, with a concentration of 5 × 10¹²/ml). The prognosis of patients was analyzed by imaging twice a year. In the gene group, the 1-, 3-, and 5-year survival rates were 91.4, 63.6, and 52.1%. In the control group, the survival rates were 84.3, 54.4, and 32.6%, respectively. There was a significant difference in the overall survival rates between two groups. Factors associated with overall survival in univariate analysis included bilirubin, prothrombin activity, cirrhosis, and gene therapy (P < 0.05). In the multivariate analysis, it included cirrhosis, gene therapy, and bilirubin. The gene therapy hepatocellular carcinoma patients with a diameter < 5 cm could significantly reduce recurrence after operation. It was worthy of being popularized.

Apoptotic effects of ε-viniferin in combination with cis-platin in C6 cells

Glioblastoma (GBM) is one of the most common and lethal forms of primary brain tumors in human adults. Treatment options are limited, and in most cases ineffective. Natural products are sources of novel compounds endowed with therapeutic properties in many human diseases like cancer. ε-viniferin is a resveratrol dimer and well known for having antiproliferative and apoptotic effects on cancer cells. Cisplatin is a platinum containing anti-cancer drug. In this study, we aimed to investigate antiproliferative and apoptotic effects of using cis-platin and ε-viniferin alone or in combined treatment of C6 cells. Cell proliferation was detected by WST-1. Mitochondrial membrane potential changes in the cells (ΔΨm) were evaluated using cationic dye JC1. Apoptotic index which is a hallmark of late apoptosis was detected by using Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method and apoptotic alterations were observed by transmission electron microscope (TEM). Activation of caspase-8, -9, -3 in C6 cells at various incubation periods was measured by flow cytometer. Apoptotic index increased at highest level in only combined treatment cells (91.6%) after 48 h incubation. These results were supported by TEM images. Caspase-8 activation in C6 cells increased to a maximum (12.5%) after 6 h by using combined cis-platin/ε-viniferin treatment (13.25/95 μM). Caspase-9 was activated at 44.5% after combined treatment for 24 h. This rate is higher than using cis-platin (14.2%) or ε-viniferin (43.3%) alone. The combined 13.25 μM/cisplatin and 95 μM ε-viniferin treatment caused maximum caspase-3 activation in C6 cells (15.5%) at the end of the 72 h incubation. In conclusion, it was observed that caspase-8, -9, -3 activation which was determined in vitro, trigerred apoptotic mechanism in C6 cells by using low concentrations of combined cis-platin and ε-viniferin.

Extracellular Matrix, a Hard Player in Angiogenesis

The extracellular matrix (ECM) is a complex network of proteins, glycoproteins, proteoglycans, and polysaccharides. Through multiple interactions with each other and the cell surface receptors, not only the ECM determines the physical and mechanical properties of the tissues, but also profoundly influences cell behavior and many physiological and pathological processes. One of the functions that have been extensively explored is its impingement on angiogenesis. The strong impact of the ECM in this context is both direct and indirect by virtue of its ability to interact and/or store several growth factors and cytokines. The aim of this review is to provide some examples of the complex molecular mechanisms that are elicited by these molecules in promoting or weakening the angiogenic processes. The scenario is intricate, since matrix remodeling often generates fragments displaying opposite effects compared to those exerted by the whole molecules. Thus, the balance will tilt towards angiogenesis or angiostasis depending on the relative expression of pro- or anti-angiogenetic molecules/fragments composing the matrix of a given tissue. One of the vital aspects of this field of research is that, for its endogenous nature, the ECM can be viewed as a reservoir to draw from for the development of new more efficacious therapies to treat angiogenesis-dependent pathologies.

Antitumor activity of combined endostatin and thymidine kinase gene therapy in C6 glioma models

The combination of Endostatin (ES) and Herpes Simplex Virus thymidine kinase (HSV‐TK) gene therapy is known to have antitumor activity in bladder cancer. The potential effect of ES and TK therapy in glioma has not yet been investigated. In this study, pTK‐internal ribosome entry site (IRES), pIRES‐ES, and pTK‐IRES‐ES plasmids were constructed; pIRES empty vector served as the negative control. The recombinant constructs were transfected into human umbilical vein endothelial cells (HUVECs) ECV304 and C6 rat glioma cell line. Ganciclovir (GCV) was used to induce cell death in transfected C6 cells. We found that ECV304 cells expressing either ES or TK‐ES showed reduced proliferation, decreased migration capacity, and increased apoptosis, as compared to untransfected cells or controls. pTK‐IRES‐ES/GCV or pTK‐IRES/GCV significantly suppressed cell proliferation and induced cell apoptosis in C6 cells, as compared to the control. In addition, the administration of pIRES‐ES, pTK‐IRES/GCV, or pTK‐IRES‐ES/GCV therapy improved animal activity and behavior; was associated with prolonged animal survival, and a lower microvessel density (MVD) value in tumor tissues of C6 glioma rats. In comparison to others, dual gene therapy in form of pTK‐IRES‐ES/GCV had a significant antitumor activity against C6 glioma. These findings indicate combined TK and ES gene therapy was associated with a superior antitumor efficacy as compared to single gene therapy in C6 glioma.