A double suicide gene system driven by vascular endothelial growth factor promoter selectively kills human hepatocellular carcinoma cells

Recent advances of engineered oncolytic viruses-based combination therapy for liver cancer

Liver cancer is a major malignant tumor, which seriously threatens human health and increases the economic burden on patients. At present, gene therapy has been comprehensively studied as an excellent therapeutic measure in liver cancer treatment. Oncolytic virus (OV) is a kind of virus that can specifically infect and kill tumor cells. After being modified by genetic engineering, the specificity of OV infection to tumor cells is increased, and its influence on normal cells is reduced. To date, OV has shown its effectiveness and safety in experimental and clinical studies on a variety of tumors. Thus, this review primarily introduces the current status of different genetically engineered OVs used in gene therapy for liver cancer, focuses on the application of OVs and different target genes for current liver cancer therapy, and identifies the problems encountered in OVs-based combination therapy and the corresponding solutions, which will provide new insights into the treatment of liver cancer.

Specific driving of the suicide E gene by the CEA promoter enhances the effects of paclitaxel in lung cancer

Classical chemotherapy for lung cancer needs new strategies to enhance its antitumor effect. The cytotoxicity, nonspecificity, and low bioavailability of paclitaxel (PTX) limits their use in this type of cancer. Suicide gene therapy using tumor-specific promoters may increase treatment effectiveness. We used carcinoembryonic antigen (CEA) as a tumor-specific promoter to drive the bacteriophage E gene (pCEA-E) towards lung cancer cells (A-549 human and LL2 mice cell lines) but not normal lung cells (L132 human embryonic lung cell line), in association with PTX as a combined treatment. The study was carried out using cell cultures, tumor spheroid models (MTS), subcutaneous induced tumors and lung cancer stem cells (CSCs). pCEA-E induced significant inhibition of A-549 and LL2 cell proliferation in comparison to L132 cells, which have lower CEA expression levels. Moreover, pCEA-E induced an important decrease in volume growth of A-549 and LL2 MTS producing intense apoptosis, in comparison to L132 MTS. In addition, pCEA-E enhanced the antitumor effects of PTX when combined, showing a synergistic effect. This effect was also observed in A-549 CSCs, which have been related to the recurrence of cancer. The in vivo study corroborated the effectiveness of the pCEA-E-PTX combined therapy, inducing a greater decrease in tumor volume compared to PTX and pCEA-E alone. Our results suggest that the CEA promoter is an excellent candidate for directing E gene expression specifically towards lung cancer cells, and may be used to enhance the effectiveness of PTX against this type of tumor.

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.

Connexin 43 SUMOylation improves gap junction functions between liver cancer stem cells and enhances their sensitivity to HSVtk/GCV

Connexin 43 (Cx43) can be modified and regulated by small ubiquitin-like modifier (SUMO)1; however, its role in liver cancer stem cells is poorly understood. In this study, we found a significant difference in the expression of Cx43 and SUMO1 between cancer stem cells and non-cancer stem cells in liver cancer. In liver cancer stem cells, Cx43 was almost absent, although the level of SUMO1 was significantly higher than that in non-cancer stem cells. Further experiments confirmed that the conjugated site of Cx43 by SUMO1 was located in Lys-144 and Lys-237, both of which are highly conserved among species. By the co-expression of Cx43 and SUMO1 in cancer stem cells, the gap junction intercellular communication (GJIC) of liver cancer stem cells was obviously improved. Using this feature, we verified whether it could effectively increase the sensitivity of cancer stem cells to the herpes simplex virus 1 thymidine kinase (HSVtk) gene in combination with ganciclovir (GCV), a conventional chemotherapeutic drug, in vitro and in vivo. As expected, increasing the expression of Cx43 SUMOylation in liver cancer stem cells effectively enhanced their sensitivity to HSVtk/GCV. On the whole, this study revealed a novel method which may be used to effectively restore GJIC in cancer stem cells in liver cancer, which enhances their sensitivity to conventional chemotherapeutic drugs.

Can We Predict Gene Expression by Understanding Proximal Promoter Architecture?

We review computational predictions of expression from the promoter architecture - the set of transcription factors that can bind the proximal promoter. We focus on spatial expression patterns in animals with complex body plans and many distinct tissue types. This field is ripe for change as functional genomics datasets accumulate for both expression and protein-DNA interactions. While there has been some success in predicting the breadth of expression (i.e., the fraction of tissue types a gene is expressed in), predicting tissue specificity remains challenging. We discuss how progress can be achieved through either machine learning or complementary combinatorial data mining. The likely impact of single-cell expression data is considered. Finally, we discuss the design of artificial promoters as a practical application.