Lentivirus-mediated CD/TK fusion gene transfection neural stem cell therapy for C6 glioblastoma

Combination of microRNA and suicide gene for targeting Glioblastoma: Inducing apoptosis and significantly suppressing tumor growth in vivo

Glioblastoma (GBM), a grade IV brain tumor, presents a severe challenge in treatment and eradication due to its high genetic variability and the existence of stem-like cells with self-renewal potential. Conventional therapies fall short of preventing recurrence and fail to extend the median survival of patients significantly. However, the emergence of gene therapy, which has recently obtained significant clinical outcomes, brings hope. It has the potential to be a suitable strategy for the treatment of GBM. Notably, microRNAs (miRNAs) have been noticed as critical players in the development and progress of GBM. The combined usage of hsa-miR-34a and Cytosine Deaminase (CD) suicide gene and 5-fluorocytosine (5FC) prodrug caused cytotoxicity against U87MG Glioma cells in vitro. The apoptosis and cell cycle arrest rates were measured by flow cytometry. The lentiviral vector generated overexpression of CD/miR-34a in the presence of 5FC significantly promoted apoptosis and caused cell cycle arrest in U87MG cells. The expression level of the BCL2, SOX2, and P53 genes, target genes of hsa-miR-34a, was examined by quantitative real-time PCR. The treatment led to a substantial downregulation of Bcl2 and SOX2 genes while elevating the expression levels of Caspase7 and P53 genes compared to the scrambled control. The hsa-miR-34a hindered the proliferation of GBM cancer cells and elevated apoptosis through the P53-miR-34a-Bcl2 axis. The CD suicide gene with 5FC treatment demonstrated similar results to miR-34a in the apoptosis, cell cycle, and real-time assays. The combination of CD and miR-34a produced a synergistic effect. In vivo, anti-GBM efficacy evaluation in rats bearing intracranial C6 Glioma cells revealed a remarkable induction of apoptosis and a significant inhibition of tumor growth compared with the scrambled control. The simultaneous use of CD/miR-34a with 5FC almost entirely suppressed tumor growth in rat models. The combined application of hsa-miR-34a and CD suicide gene against GBM tumors led to significant induction of apoptosis in U87MG cells and a considerable reduction in tumor growth in vivo.

Potent antifungal agents and use of nanocarriers to improve delivery to the infected site: A systematic review

There are four major classes of antifungals with the predominant mechanism of action being targeting of cell wall or cell membrane. As in other drugs, low solubility of these compounds has led to low bioavailability in target tissues. Enhanced drug dosages have effects such as toxicity, drug-drug interactions, and increased drug resistance by fungi. This article reviews the current state-of-the-art of antifungals, structure, mechanism of action, other usages, and toxic side effects. The emergence of nanoformulations to transport and uniformly release cargo at the target site is a boon in antifungal treatment. The article details research that lead to the development of nanoformulations of antifungals and potential advantages and avoidance of the lacunae characterizing conventional drugs. A range of nanoformulations based on liposomes, polymers are in various stages of research and their potential advantages have been brought out. It could be observed that under similar dosages, test models, and duration, nanoformulations provided enhanced activity, reduced toxicity, higher uptake and higher immunostimulatory effects. In most instances, the mechanism of antifungal activity of nanoformulations was similar to that of regular antifungal. There are possibilities of coupling multiple antifungals on the same nano-platform. Increased activity coupled with multiple mechanisms of action presents for nanoformulations a tremendous opportunity to overcome antifungal resistance. In the years to come, robust methods for the preparation of nanoformulations taking into account the repeatability and reproducibility in action, furthering the studies on nanoformulation toxicity and studies of human models are required before extensive use of nanoformulations as a prescribed drug.

Recent progress in the research of suicide gene therapy for malignant glioma

Malignant glioma, which is characterized by diffuse infiltration into the normal brain parenchyma, is the most aggressive primary brain tumor with dismal prognosis. Over the past 40 years, the median survival has only slightly improved. Therefore, new therapeutic modalities must be developed. In the 1990s, suicide gene therapy began attracting attention for the treatment of malignant glioma. Some clinical trials used a viral vector for suicide gene transduction; however, it was found that viral vectors cannot cover the large invaded area of glioma cells. Interest in this therapy was recently revived because some types of stem cells possess a tumor-tropic migratory capacity, which can be used as cellular delivery vehicles. Immortalized, clonal neural stem cell (NSC) line has been used for patients with recurrent high-grade glioma, which showed safety and efficacy. Embryonic and induced pluripotent stem cells may be considered as sources of NSC because NSC is difficult to harvest, and ethical issues have been raised. Mesenchymal stem cells are alternative candidates for cellular vehicle and are easily harvested from the bone marrow. In addition, a new type of nonlytic, amphotropic retroviral replicating vector encoding suicide gene has shown efficacy in patients with recurrent high-grade glioma in a clinical trial. This replicating viral capacity is another possible candidate as delivery vehicle to tackle gliomas. Herein, we review the concept of suicide gene therapy, as well as recent progress in preclinical and clinical studies in this field.

Lentivirus-mediated CDglyTK gene-modified free flaps by intra-artery perfusion show targeted therapeutic efficacy in rat model of breast cancer

Background

Free flap-mediated gene therapy in the tumor bed following surgical resection is a promising approach in cancer targeted treatment of residual disease. We investigated the selective killing efficacy of a lentivirus-mediated cytosine deaminase-thymidine kinase (CDglyTK) gene in transplanted breast cancer delivered into a free flap by intra-artery perfusion.

Methods

Proliferation, apoptosis, and cell cycle of rat SHZ-88 breast cancer cells transfected with a lentivirus-mediated CD/TK gene were measured following treatment with ganciclovir and 5-flucytosine in vitro. A model of residual disease of breast cancer in a rat superficial inferior epigastric artery (SIEA) flap model was used to study the therapeutic potential of a double suicide CD/TK and prodrug system in vivo.

Results

Killing efficacy of the double suicide CD/TK and prodrug system on SHZ-88 cells was mediated by increased apoptosis and cell cycle arrest at the G1 phase with significant bystander effect. Following recombinant lentivirus transfection of rat SIEA flap by intra-artery perfusion, CD/TK gene expression was limited to the flap, and the volume and weight of transplanted tumors were significantly reduced without observable toxicity.

Conclusions

SIEA flaps transfected with a lentivirus-mediated CDglyTK gene by intra-artery perfusion effectively suppress transplanted breast tumor growth without obvious systemic toxic effects in rats.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-6111-5) contains supplementary material, which is available to authorized users.

Using the lentiviral vector system to stably express chicken P-gp and BCRP in MDCK cells for screening the substrates and studying the interplay of both transporters

Transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are known to influence the pharmacokinetics and toxicity of substrate drugs. However, no detailed information is as yet available about functional activity and substrate spectra of chicken P-gp and BCRP. In this study, BCRP single and BCRP/P-gp double-transfected MDCK cell lines (named MDCK-chAbcg2 and MDCK-chAbcg2/Abcb1, respectively) were generated using lentiviral vector system to develop reliable systems for screening the substrates for these two transporters and study the interplay between them. The constructed cell lines significantly expressed functional exogenous proteins and expression persisted for at least 50 generations with no decrease. Enrofloxacin, ciprofloxacin, tilmicosin, sulfadiazine, ampicillin and clindamycin were classified as the substrates of chicken P-gp according to the rules suggested by FDA, as their net efflux ratios were greater than two. Similarly, enrofloxacin, ciprofloxacin, tilmicosin, florfenicol, ampicillin and clindamycin were classified as the substrates of BCRP. Among these drugs, enrofloxacin, ciprofloxacin, tilmicosin, ampicillin, and clindamycin were the cosubstrates of P-gp and BCRP, however, chicken BCRP and P-gp exhibit different affinities to the shared substrates at different concentrations by blocking either one or both transport with specific inhibitors in the coexpression system. It was also found that ceftiofur, amoxicillin and doxycycline were not substrates of either chicken BCRP or the substrates of chicken P-gp. These constructed cell models provide useful systems for high-throughput screening of the potential substrates of chicken BCRP and P-gp as well as the drug-drug interaction mediated via chicken BCRP and P-gp.

Construction of a novel vector expressing Survivin-shRNA and fusion suicide gene yCDglyTK and its application in inhibiting proliferation and migration of colon cancer cells

Despite progress achieved in cancer chemotherapy in recent decades, adverse effects remain a limiting factor for a number of patients with colorectal cancer, suggesting the requirement for novel therapeutic strategies. Gene therapy appears to be a promising strategy for treating cancer. The present study aimed to investigate the anti-tumor effect of a combined gene therapy, using Survivin downregulation by RNAi and a fusion suicide gene yCDglyTK therapy system. A triple-gene vector expressing Survivin-targeted small hairpin RNA (Survivin-shRNA) and fusion suicide gene yCDglyTK was constructed, and administered to HCT116 cells. Survivin expression decreased significantly and yCDglyTK fusion gene expression was confirmed by both reverse transcription-quantitative polymerase chain reaction and western blot analysis. Introduction of Survivin-shRNA into yCDglyTK/prodrug system eradicated colon cancer cells and induced apoptosis more effectively. Furthermore, this therapeutic system is able to inhibit the migration of HCT116 cells. These results indicate that the recombinant plasmid may serve as a novel gene therapy approach to treat colorectal carcinoma.

All-trans retinoic acid enhances bystander effect of suicide gene therapy in the treatment of breast cancer

All-trans retinoic acid (ATRA) has been shown to enhance the expression of connexin 43 (Cx43) and the bystander effect (BSE) in suicide gene therapy. These in turn improve effects of suicide gene therapies for several tumor types. However, whether ATRA can improve BSE remains unclear in suicide gene therapy for breast cancer. In the present study, MCF-7, human breast cancer cells were treated with ATRA in combination with a VEGFP-TK/CD gene suicide system developed by our group. We found that this combination enhances the efficiency of cell killing and apoptosis of breast cancer by strengthening the BSE in vitro. ATRA also promotes gap junction intercellular communication (GJIC) in MCF-7 cells by upregulation of the connexin 43 mRNA and protein in MCF-7 cells. These results indicate that enhancement of GJIC by ATRA in suicide gene system might serve as an attractive and cost-effective strategy of therapy for breast cancer cells.

Combined enzyme/prodrug treatment by genetically engineered AT-MSC exerts synergy and inhibits growth of MDA-MB-231 induced lung metastases

Background

Metastatic spread of tumor cells remains a serious problem in cancer treatment. Gene-directed enzyme/prodrug therapy mediated by tumor-homing genetically engineered mesenchymal stromal cells (MSC) represents a promising therapeutic modality for elimination of disseminated cells. Efficacy of gene-directed enzyme/prodrug therapy can be improved by combination of individual systems. We aimed to define the combination effect of two systems of gene therapy mediated by MSC, and evaluate the ability of systemically administered genetically engineered mesenchymal stromal cells to inhibit the growth of experimental metastases derived from human breast adenocarcinoma cells MDA-MB-231/EGFP.

Methods

Human adipose tissue-derived mesenchymal stromal cells (AT-MSC) were retrovirally transduced with fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (CD::UPRT) or with Herpes simplex virus thymidine kinase (HSVtk). Engineered MSC were cocultured with tumor cells in the presence of prodrugs 5-fluorocytosin (5-FC) and ganciclovir (GCV). Combination effect of these enzyme/prodrug approaches was calculated. SCID/bg mice bearing experimental lung metastases were treated with CD::UPRT-MSC, HSVtk-MSC or both in combination in the presence of respective prodrug(s). Treatment efficiency was evaluated by EGFP-positive cell detection by flow cytometry combined with real-time PCR quantification of human cells in mouse organs. Results were confirmed by histological and immunohistochemical examination.

Results

We demonstrated various extent of synergy depending on tested cell line and experimental setup. The strongest synergism was observed on breast cancer-derived cell line MDA-MB-231/EGFP. Systemic administration of CD::UPRT-MSC and HSVtk-MSC in combination with 5-FC and GCV inhibited growth of MDA-MB-231 induced lung metastases.

Conclusions

Combined gene-directed enzyme/prodrug therapy mediated by MSC exerted synergic cytotoxic effect and resulted in high therapeutic efficacy in vivo.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-015-0149-2) contains supplementary material, which is available to authorized users.