The promise of lentiviral gene therapy for liver cancer

Alarmin augments the antitumor immunity of lentiviral vaccine in ectopic, orthotopic and autochthonous hepatocellular carcinoma mice

It is a daunting therapeutic challenge to completely eradicate hepatocellular carcinoma (HCC) from patients. Alpha-fetoprotein (AFP) -based vaccines appear promising, however the efficacy needs to be improved. Methods: Here, we explore if fusing high-mobility group nucleosome binding protein 1 (HMGN1), a potent immunoadjuvant, to AFP (lenti-HA) can augment the antitumor immunity of AFP-expressing lentiviral vector (lenti-AFP), a vehicle extensively employed for genetic immunization with high transduction efficacy and good safety profiles. The antitumor immunity of Lenti-HA was systemically assessed in ectopic, orthotopic and autochthonous HCC models. Results: Lenti-HA elicited strong anti-HCC effects in mice and amplified the antitumor immunity of lenti-AFP by reducing effective dose 6-fold. Importantly, lenti-HA induced a robust antitumor immune response with prolonged survival rate and improved the immune and tumor microenvironment in mice with carcinogen-induced autochthonous HCC. Lenti-HA localized primarily to lymphoid organs with no preference for specific immune cell types. Activated dendritic cells (DCs), particularly CD103+CD11b- DCs, were also actively recruited to lymph nodes in lenti-HA-treated HCC mice. Moreover, lenti-HA-transduced human DCs elicited stronger immune response than lenti-AFP against HCC cells in vitro. Conclusion: Our study demonstrates that HMGN1 augments the antitumor immunity of AFP-expressing lentiviral vaccines in HCC mice and human cells in vitro and thus provides a new therapeutic strategy for HCC.

Effective Amelioration of Liver Fibrosis Through Lentiviral Vector Carrying Toxoplasma gondii gra15II in Murine Model

Our previous investigations indicated that in vitro polarization of mouse macrophages by Toxoplasma gondii type II strain dense granule protein 15 (GRA15 II ), one of the genotype-associated effectors of T. gondii, induced the phenotypes of classically activated macrophage (M1). Transfusion of the cells to mice may effectively alleviated hepatic fibrosis caused by schistosomiasis. The purpose of the study was to identify whether liver macrophages can be in vivo driven to M1 macrophages by lentiviral vector (LV) carrying GRA15 II gene (LV-gra15 II ) and to explore the potential mechanism by which the LV-gra15 II -activated liver macrophage (LV-gra15 II -M) ameliorates the hepatic fibrosis in schistosomiasis. The mice were treated with LV-gra15 II by hydrodynamic injection via the tail vein followed by challenge of Schistosoma japonicum (S. japonicum). Our experiments showed that LV-gra15 II was successfully delivered to liver macrophages and GRA15II was persistently expressed in the macrophages of mice for at least 2 months. Furthermore, the LV-gra15 II infected macrophages were polarized to M1 macrophages in vivo. Consequently, mice with schistosomiasis receiving LV-gra15 II injection displayed a remarkable amelioration of liver granuloma formation and collagen deposition in association with downregulated expression of transforming growth factor-beta1, arginase 1 (Arg-1), α-smooth muscle actin, and an increased expression of matrix metalloproteinase 13 (MMP13). Simultaneously, no negative effects of liver function and vitality of mice were noted. The in vitro experiments indicated that the C-C motif chemokine ligand 2 and nitric oxide level were elevated in LV-gra15 II -M cultural supernatants; hepatocyte growth factor expression was enhanced in LV-gra15 II -M. In addition, LV-gra15 II -M not only secreted MMP13, which greatly degraded type I collagen, but also induced murine hepatic stellate cell (HSC) line (JS1) apoptosis in the co-culture system. Taken together, we identified for the first time that LV-gra15 II may in vivo drive liver macrophages to M1 macrophage phenotypes, which helps for alteration of the liver fibrotic microenvironment with collagen dissolution, HSC deactivation, apoptosis and hepatocyte protection. Our study gives an insight into the use of gene delivery with parasite-derived immunomodulatory factor as a potential immune cell activating agent to re-equilibrate the other pathogen-induced immune response in some chronic diseases.

CPNE1 silencing inhibits the proliferation, invasion and migration of human osteosarcoma cells

Osteosarcoma (OS) is the most common primary malignancy of the bone affecting children and adolescents. Copine 1 (CPNE1) is a highly conserved calcium-dependent phospholipid-binding protein and may function in regulating signal transduction and membrane trafficking. In the present study, we investigated CPNE1 expression in osteosarcoma tissues and cells, and studied the effects of small interfering RNA (siRNA)-targeting CPNE1 on proliferation, metastasis and chemosensitivity of the osteosarcoma cells. The results demonstrated that CPNE1 was highly expressed in the osteosarcoma tissues and cell lines. Moreover, functional investigations confirmed that CPNE1 knockdown significantly inhibited cell proliferation, colony formation, invasion and metastasis in Saos-2 and HOS cells. Western blot analysis indicated that CPNE1 silencing downregulated the expression of many proteins associated with tumorigenesis and development, including Ras, MEK-1/2, WNT1, β-catenin, cyclin A1, IRAK2 and cIAP2. In addition, CPNE1 downregulation enhanced the sensitivity of Saos-2 cells towards cisplatin and adriamycin. The present study provides deep insight into the clinical use of lentiviral-mediated CPNE1 silencing for osteosarcoma therapy.

A diphtheria toxin resistance marker for in vitro and in vivo selection of stably transduced human cells

We developed a selectable marker rendering human cells resistant to Diphtheria Toxin (DT). The marker (DT^R) consists of a primary microRNA sequence engineered to downregulate the ubiquitous DPH2 gene, a key enzyme for the biosynthesis of the DT target diphthamide. DT^R expression in human cells invariably rendered them resistant to DT in vitro, without altering basal cell growth. DT^R-based selection efficiency and stability were comparable to those of established drug-resistance markers. As mice are insensitive to DT, DT^R-based selection can be also applied in vivo. Direct injection of a GFP-DT^R lentiviral vector into human cancer cell-line xenografts and patient-derived tumorgrafts implanted in mice, followed by systemic DT administration, yielded tumors entirely composed of permanently transduced cells and detectable by imaging systems. This approach enabled high-efficiency in vivo selection of xenografted human tumor tissues expressing ectopic transgenes, a hitherto unmet need for functional and morphological studies in laboratory animals.

Lentivirus mediated silencing of ubiquitin specific peptidase 39 inhibits cell proliferation of human hepatocellular carcinoma cells in vitro

Background

Ubiquitin Specific Peptidase 39 (USP39) is a 65 kDa SR-related protein involved in RNA splicing. Previous studies showed that USP39 is related with tumorigenesis of human breast cancer cells.

Results

In the present study, we investigated the functions of USP39 in human hepatocellular carcinoma (HCC) cell line SMMC-7721. We knocked down the expression of USP39 through lentivirus mediated RNA interference. The results of qRT-PCR and western blotting assay showed that both the mRNA and protein levels were suppressed efficiently after USP39 specific shRNA was delivered into SMMC-7721 cells. Cell growth was significantly inhibited as determined by MTT assay. Crystal violet staining indicated that colony numbers and sizes were both reduced after knock-down of USP39. Furthermore, suppression of USP39 arrested cell cycle progression at G₂/M phase in SMMC-7721cells. In addition, Annexin V showed that downregulation of USP39 significantly increased the population of apoptotic cells.

Conclusions

All our results suggest that USP39 is important for HCC cell proliferation and is a potential target for molecular therapy of HCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s40659-015-0006-y) contains supplementary material, which is available to authorized users.

Potential Usefulness of Baculovirus-Mediated Sodium-Iodide Symporter Reporter Gene as Non-Invasively Gene Therapy Monitoring in Liver Cancer Cells: An In Vitro Evaluation

Primary liver cancer has one of the highest mortality rates of all cancers, and the main current treatments have a poor prognosis. This study aims to examine the efficiency of baculovirus vectors for transducing target gene into liver cancer cells and to evaluate the feasibility of using baculovirus vectors to deliver the sodium-iodide symporter (NIS) gene as a reporter gene through co-vector administration approach to monitor the expression of the target therapeutic gene in liver cancer gene therapy. We constructed (green fluorescent protein) GFP- and NIS-expressing baculovirus vectors (Bac-GFP and Bac-NIS), and measured the baculovirus transduction efficiency in HepG2 cells and other tumor cells (A549, SW1116 and 8505C), and it showed that the transduction efficiency and target gene expression level rose with increasing viral multiplicity of infection (MOI) in HepG2 cells, and HepG2 cells had a significantly higher transduction efficiency (60.8% at MOI = 200) than other tumor cells. Moreover, the baculovirus transduction was not cytotoxic to HepG2 cells at a higher MOI (MOI = 400). We also performed dynamic iodide uptake trials, and found that Bac-NIS-transduced HepG2 cells exhibited efficient iodide uptake which could be inhibited by sodium perchlorate (NaClO4). And we measured the correlation of fluorescent intensities and 125 I uptake amount in HepG2 cells after co-vector administration with Bac-NIS and Bac-GFP at different MOIs, and found a high correlation coefficient ( r2 = 0.8447), which provides a good basis for successfully evaluating the feasibility of baculovirus-mediated NIS reporter gene monitoring target gene expression in liver cancer therapy. Therefore, this study indicates that baculovirus vector is a potential vehicle for delivering therapeutic genes in studying liver cancer cells. And it is feasible to use a baculovirus vector to deliver NIS gene as a reporter gene to monitor the expression of target genes. It therefore provides an effective approach and a good basis for future baculovirus-mediated therapeutic gene delivering or therapeutic gene expression monitoring in liver cancer cells studies.

A new G6PD knockdown tumor-cell line with reduced proliferation and increased susceptibility to oxidative stress

Glucose-6-phosphate dehydrogenase (G6PD) has been implicated in the regulation of cellular antioxidative mechanisms. Tumor cells often lose the balance of oxidation and antioxidation, but the role of G6PD in such an imbalance is still largely unknown. To investigate the related function of G6PD in tumor cells, we established a stable line of A375 human melanoma cells with G6PD gene knockdown by a shRNA lentiviral cloning and expression system. The A375-G6PDDelta cells displayed the stable GFP coexpression after repeated freeze-thaw cycles and multiple passages, accompanied by an 88.83% suppression of the endogenous G6PD expression and a 78.47% decrease in G6PD activity. In comparison with the A375-WT cells, they were characterized by a reduced proliferation with the MTT proliferation assay, a 25% decrease in colony-forming efficiency, and an up to 40% increase of apoptotic rate with flow cytometry analysis. When further challenged by diamide-induced oxidative stress, these cells showed that a median lethal dose (LD(50)) of 1.2 mM decreased from that of the A375-WT cells (1.8 mM), and levels of NADPH and GSH decreased by 2.4-, 8.8-fold, respectively, with a 7.3-fold increase of H(2)O(2), as those of A375-WT cells. These results demonstrated that A375-G6PDDelta is a new, stable G6PD-deficient human tumor cell line, and that silencing G6PD expression decreased tumor-cell proliferation and enhanced apoptosis. In addition, G6PD gene knockdown rendered tumor cells more susceptible to diamide-induced oxidative stress. Together, our data support the important functions of G6PD in the regulation of cell growth and antioxidative capacity of tumor cells.

Biotinylated disulfide containing PEI/avidin bioconjugate shows specific enhanced transfection efficiency in HepG2 cells

Targeting of non-viral gene vectors to liver cells could offer the opportunity to cure liver diseases. In this paper, disulfide-containing polyethylenimine (PEI-SS) was synthesized from low molecular weight branched PEI and cystamine bisacrylamide (CBA), and then grafted with biotin. The obtained biotinylated PEI-SS was bioconjugated with avidin via the biotin-avidin interaction to form a novel gene vector, biotinylated PEI-SS/avidin bioconjugate (ABP-SS). Characteristics of ABP-SS and its pDNA complexes were evaluated in terms of acid-base titration, agarose gel electrophoresis, SEM morphology observation, particle size and zeta-potential measurements, and PEI-SS was used as the control. The acid-base titration results showed that ABP-SS exhibited comparable buffer capability to 25 kDa PEI. The results of gel electrophoresis indicated that ABP-SS was able to condense pDNA efficiently at an N/P ratio of 6 and could be degraded by reducing agent DTT. The ABP-SS/pDNA complexes had a mean particle size of 226 +/- 40 nm and surface charges of 25 mV. The SEM images showed that the complexes had compact structures with spherical or quadrate shapes. In vitro cell viability and transfection of ABP-SS and PEI-SS were compared in HepG2, 293T and H446 cells. Among the three different cell lines, compared with PEI-SS, ABP-SS exhibited much lower cytotoxicity and higher transfection efficacy in HepG2 cells due to the biocompatibility of avidin and the specific interactions between avidin and HepG2 cells. Molecular probes were used to reveal the cellular uptake of complexes, and the results demonstrated that ABP-SS contributes to more cellular uptake of complexes in HepG2 cells, which was consistent with the transfection results.

Blockage of HGF/c-Met system by gene therapy (adenovirus-mediated NK4 gene) suppresses hepatocellular carcinoma in mice

BACKGROUND/AIMS

Hepatocyte growth factor promotes cancer development through cell motility-promoting and angiogenic effects. NK4, a fragment of hepatocyte growth factor, acts as its receptor antagonist. We assessed effects of NK4 gene therapy against human hepatocellular carcinoma cells (HUH7) transplanted into mice.

METHODS

NK4 gene transduction was mediated by adenovirus (AdCMV.NK4). LacZ expression adenovirus (AdCMV.LacZ) was used as a control. NK4 effects on HUH7 cells first were studied in vitro. Subcutaneous HUH7 tumors established in athymic nude mice were injected with AdCMV.NK4 (n=6) or AdCMV.Lacz (n=6). Finally, after HUH7 cells were injected into the portal vein in mice with severe combined immunodeficiency to establish hepatic tumors, mice systemically were injected with AdCMV.NK4 (n=6) or AdCMV.LacZ (n=6).

RESULTS

NK4 inhibited hepatocyte growth factor-induced phosphorylation of c-Met in HUH7 cells. Invasion and migration of HUH7 cells were inhibited by NK4 transfection, which also suppressed growth of transplanted subcutaneous and liver tumors (p<0.001, p<0.01 respectively), and improved mouse survival (p<0.05). Angiogenesis assessed by small vessel density was significantly decreased in the NK4-treated group.

CONCLUSIONS

NK4 inhibited tumor cell motility and angiogenesis, greatly suppressing growth of HUH7 tumors transplanted into mouse liver. NK4 gene therapy thus showed apparent promise for treatment of hepatocellular carcinoma.