Enhancing adenovirus-mediated gene transfer in vitro and in vivo by addition of protamine and hydrocortisone

Mechanisms of unprimed and dexamethasone-primed nonviral gene delivery to human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) are under intense study for applications of cell and gene therapeutics because of their unique immunomodulatory and regenerative properties. Safe and efficient genetic modification of hMSCs could increase their clinical potential by allowing functional expression of therapeutic transgenes or control over behavior and differentiation. Viral gene delivery is efficient, but suffers from safety issues, while nonviral methods are safe, but highly inefficient, especially in hMSCs. Our lab previously demonstrated that priming cells before delivery of DNA complexes with dexamethasone (DEX), an anti‐inflammatory glucocorticoid drug, significantly increases hMSC transfection success. This work systematically investigates the mechanisms of hMSC transfection and DEX‐mediated enhancement of transfection. Our results show that hMSC transfection and its enhancement by DEX are decreased by inhibiting classical intracellular transport and nuclear import pathways, but DEX transfection priming does not increase cellular or nuclear internalization of plasmid DNA (pDNA). We also show that hMSC transgene expression is largely affected by pDNA promoter and enhancer sequence changes, but DEX‐mediated enhancement of transfection is unaffected by any pDNA sequence changes. Furthermore, DEX‐mediated transfection enhancement is not the result of increased transgene messenger RNA transcription or stability. However, DEX‐priming increases total protein synthesis by preventing hMSC apoptosis induced by transfection, resulting in increased translation of transgenic protein. DEX may also promote further enhancement of transgenic reporter enzyme activity by other downstream mechanisms. Mechanistic studies of nonviral gene delivery will inform future rationally designed technologies for safe and efficient genetic modification of clinically relevant cell types.

OvAd1, a Novel, Potent, and Selective Chimeric Oncolytic Virus Developed for Ovarian Cancer by 3D-Directed Evolution

Effective therapeutics for ovarian cancer continue to be urgently needed, particularly for chemotherapy-resistant cases. Here we present both a 3D-Matrigel culture-based expansion of our directed evolution method for generation of oncolytic virotherapies and two promising ovarian-cancer targeted oncolytic viruses, OvAd1 and OvAd2. OvAd1 was developed using Matrigel cell cultures, whereas OvAd2 was developed in parallel using traditional monolayer tissue culture methods. Both viruses are potent against a panel of platinum-resistant ovarian cancer cell lines and are attenuated on normal cells in vitro, resulting in therapeutic windows of ∼200-fold. We observed two benefits of the use of Matrigel-based cultures for directed evolution of these oncolytics: (1) use of Matrigel generated a bioselected pool that was more strongly attenuated on normal cells while retaining its potency against ovarian cancer cells, and (2) in an ovarian carcinomatosis model, the Matrigel-derived virus OvAd1 suppressed all tumor growth while the non-Matrigel-derived virus was 50% effective. Neither virus stimulated formation of peritoneal adhesions as seen for Ad5-based therapies. Consequently, these viruses are novel candidates for development as new effective treatments for aggressive ovarian cancer.

Clinical significance of ADAM10 expression in laryngeal carcinoma

Recent findings suggest that upregulated a disintegrin and metalloproteinase (ADAM)10 expression participates in the progression of multiple types of cancer. However, the expression pattern and clinicopathological significance of ADAM10, and its potential prognostic role in laryngeal carcinoma remains to be explored. The present study firstly determined the significantly elevated expression status of ADAM10 protein and messenger RNA in laryngeal carcinoma tissues compared with that in adjacent non-tumor tissues by western blotting and reverse transcription-quantitative polymerase chain reaction analysis. Next, the expression of ADAM10 and the proliferation marker Ki-67 was examined in 78 laryngeal carcinoma and 35 adjacent non-tumor specimens using immunohistochemistry. Overexpressed ADAM10 in laryngeal carcinoma was detected, which correlated with T classification (P<0.01), clinical stage (P<0.01), pathology (P=0.034) and Ki-67 expression (P<0.01). Furthermore, the expression of ADAM10 was positively correlated with the expression of Ki-67 (R²=0.22; P<0.01). The Kaplan-Meier method revealed that the group with overexpressed ADAM10 exhibited shorter overall survival time compared with those with low ADAM10 expression. Our findings indicated that ADAM10 serves a notable role in the progression and prognosis of laryngeal carcinoma.

Glucocorticoid Cell Priming Enhances Transfection Outcomes in Adult Human Mesenchymal Stem Cells

Human mesenchymal stem cells (hMSCs) are one of the most widely researched stem cell types with broad applications from basic research to therapeutics, the majority of which require introduction of exogenous DNA. However, safety and scalability issues hinder viral delivery, while poor efficiency hinders nonviral gene delivery, particularly to hMSCs. Here, we present the use of a pharmacologic agent (glucocorticoid) to overcome barriers to hMSC DNA transfer to enhance transfection using three common nonviral vectors. Glucocorticoid priming significantly enhances transfection in hMSCs, demonstrated by a 3-fold increase in efficiency, 4-15-fold increase in transgene expression, and prolonged transgene expression when compared to transfection without glucocorticoids. These effects are dependent on glucocorticoid receptor binding and caused in part by maintenance of normal metabolic function and increased cellular (5-fold) and nuclear (6-10-fold) DNA uptake over hMSCs transfected without glucocorticoids. Results were consistent across five human donors and in cells up to passage five. Glucocorticoid cell priming is a simple and effective technique to significantly enhance nonviral transfection of hMSCs that should enhance their clinical use, accelerate new research, and decrease reliance on early passage cells.

Effects of ADAM10 upregulation on progression, migration, and prognosis of nasopharyngeal carcinoma

A disintegrin and metalloprotease 10 (ADAM10) is a typical member of the ADAMs family, which has been reported to be upregulated in various types of cancers and contribute to cancer progression and metastasis. However, little is known about the role of ADAM10 in nasopharyngeal carcinoma (NPC). The purpose of this study is to explore ADAM10 expression status and its biological functions in NPC. We first examined the expression of ADAM10 in NPC tissues and cell lines by immunohistochemistry, Western blotting, PCR, and immunofluorescence analysis. We observed that ADAM10 was significantly elevated in NPC and its expression level was correlated with T classification (P = 0.044), distant metastasis (P = 0.016), TNM clinical stage (P = 0.013), and proliferation marker Ki‐67 expression (P = 0.001). Patients with NPC with high expression of ADAM10 had shorter overall survival rates. In addition, knockdown of ADAM10 by RNAi was found to inhibit the CNE‐2 cell proliferation and migration. Our findings hinted that overexpression of ADAM10 promotes the progression and migration of NPC, which makes it a potential therapeutic target for the treatment of tumor metastases in NPC.

miR-124 regulates fetal pulmonary epithelial cell maturation

MicroRNAs are a family of small noncoding RNAs that regulate the expression of their target proteins at the posttranscriptional level. Their functions cover almost every aspect of cell physiology. However, the roles of microRNAs in fetal lung development are not completely understood. The objective of this study is to investigate the regulation and molecular mechanisms of alveolar epithelial cell maturation during fetal lung development by miR-124. We discovered that miR-124 was downregulated during rat fetal lung development and predominantly expressed in the epithelial cells at late stage of the lung development. Overexpression of miR-124 with an adenovirus vector led to the inhibition of epithelial maturation in rat fetal lung organ cultures and fetal alveolar epithelial type II cells, as demonstrated by a decrease in the type II cell marker expression and an increase in glycogen content. We further demonstrated by luciferase reporter assays that miR-124 inhibited the NF-κB, cAMP/PKA, and MAPK/ERK pathways. In addition, nuclear factor I/B (NFIB), a critical protein in fetal lung maturation, was validated as a direct target of miR-124. Furthermore, miR-124 expression was induced by the Wnt/β-catenin signaling pathway through a direct interaction of LEF1 and the miR-124 promoter region. We concluded that miR-124 downregulation is critical to fetal lung epithelial maturation and miR-124 inhibits this maturation process at least partially through the inhibition of NFIB.

Knockout of ADAM10 enhances sorafenib antitumor activity of hepatocellular carcinoma in vitro and in vivo

Sorafenib (SOR), a vascular endothelial growth factor receptor (VEGFR) inhibitor, is in wide clinical use for the treatment and prevention of liver cancer. However, extended SOR administration for hepatocellular carcinoma (HCC) induces drug resistance thereby limiting its efficacy and highlighting the need for improved therapeutic strategies. It has previously been demonstrated that knockout of a disintegrin and metalloproteinase 10 (ADAM10) via siRNA induced cancer apoptosis and decreased chemotherapy drug resistance. However, whether knockout of ADAM10 is able to decrease SOR resistance remains to be determined. Therefore, in the present study, the effect of siRNA-ADAM10 in combination with SOR was analyzed in HCC cell lines (HepG2) by inhibiting tumor growth and simultaneously reducing doses of SOR. Cell proliferation, apoptosis, migration, invasion and involvement in receptor signaling were determined after siRNA-ADAM10 was applied in combination with SOR treatment. Tumor growth ability in nude mice was also detected. The results showed that siRNA-ADAM10 in combination with SOR treatment in HCC cancer cells significantly suppressed proliferation, migration and invasion, and induced tumor apoptosis in vitro, and suppressed tumor growth in vivo. In addition, the results showed that knockout of ADAM10 by siRNA inhibited the constitutive phosphorylation of PI3K and AKT, which may contribute to the reduction of SOR resistance. Collectively, our experimental results indicate that knockout of ADAM10 by siRNA increased the SOR antitumor activity of liver cancer in vitro and in vivo, and that this additive combination is a promising drug candidate for treatment of HCC.

COX-2 silencing enhances tamoxifen antitumor activity in breast cancer in vivo and in vitro

Tamoxifen (Tam), a selective estrogen receptor modulator, is in wide clinical use for the treatment and prevention of breast cancer. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy and highlighting the need for improved therapeutic strategies. Cyclooxygenase-2 (COX-2) silencing via a replication-incompetent lentivirus (LV-COX-2) induce cancer apoptosis and suppresses VEGF gene expression. In this study, the effect of LV-COX-2 infection, either alone or in combination with TAM, was analyzed in a breast cell lines for suppressing VEGF expression and simultaneously reducing doses of TAM. Cell proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, an receptor signaling were determined after LV-COX-2 combination with TAM treatment. In addition, tumor growth ability in nude mice was detected to define the combination treatment effect in tumorigenesis in vivo. It is found that LV-COX-2 combination with TAM treatment in breast cancer cell significantly suppressed the proliferation and metastasis, and induced tumor apoptosis in vitro, and tumor growth also was suppressed in vivo. In addition, we also found that LV-COX-2 combination with TAM treatment could inhibit angiogenesis and VEGF expression. Taken together, our experimental results indicate that LV-COX-2 combination with TAM has promising outcome in anti-metastatic and apoptotic studies. Furthermore, these results showed that LV-COX-2 combination with TAM is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF.

Protamine sulfate-calcium carbonate-plasmid DNA ternary nanoparticles for efficient gene delivery

Ternary nanoparticles, protamine sulfate-calcium carbonate-plasmid DNA (PS-CaCO3-DNA), were prepared for efficient gene delivery. By adding the cationic polypeptide PS in the co-precipitation system of calcium carbonate and DNA, PS-CaCO3-DNA nanoparticles could be formed by self-assembly facilely. The effect of PS on the properties of the ternary nanoparticles was studied by varying the PS amount in the nanoparticles. The size and ζ-potential measurements indicated that the ternary nanoparticles with an appropriate PS amount exhibited a decreased size and an increased ζ-potential. The in vitro gene transfections mediated by different nanoparticles in 293T cells and HeLa cells were carried out in the presence of 10% fetal bovine serum, using pGL3-Luc and pEGFP-C1 as reporter plasmids. As compared with both PS-DNA nanoparticles and CaCO3-DNA nanoparticles, PS-CaCO3-DNA nanoparticles exhibited significantly enhanced gene delivery efficiency, which was higher than that of Lipofectamine 2000-DNA. Confocal microscopy observation showed that PS-CaCO3-DNA nanoparticles could efficiently deliver DNA to cell nuclei. These results indicated that the ternary PS-CaCO3-DNA nanoparticles prepared in this study have promising applications in gene delivery.

Dual-functionalized calcium carbonate based gene delivery system for efficient gene delivery

Dual-functionalized KALA/PS/CaCO₃/DNA nanoparticles containing a cell penetrating peptide (KALA) and protamine sulfate (PS) could effectively mediate gene transfection at a low DNA concentration.

Adenovector-mediated gene delivery to human umbilical cord mesenchymal stromal cells induces inner ear cell phenotype

Hearing is one of our main sensory systems and having a hearing disorder can have a significant impact in an individual's quality of life. Sensory neural hearing loss (SNHL) is the most common form of hearing loss; it results from the degeneration of inner ear sensory hair cells and auditory neurons in the cochlea, cells that are terminally differentiated. Stem cell-and gene delivery-based strategies provide an opportunity for the replacement of these cells. In recent years, there has been an increasing interest in gene delivery to mesenchymal stem cells. In this study, we evaluated the potential of human umbilical cord mesenchymal stromal cells (hUCMSCs) as a possible source for regenerating inner ear hair cells. The expression of Atoh1 induced the differentiation of hUCMSCs into cells that resembled inner ear hair cells morphologically and immunocytochemically, evidenced by the expression of hair cell-specific markers. The results demonstrated for the first time that hUCMSCs can differentiate into hair cell-like cells, thus introducing a new potential tissue engineering and cell transplantation approach for the treatment of hearing loss.

Safety of glucocorticoids in cancer patients treated with oncolytic adenoviruses

Oncolytic adenoviruses are an emerging treatment option for advanced and refractory cancer. Such patients are often treated with corticosteroids to ameliorate tumor associated symptoms. Thus, it is important to evaluate whether safety is affected by immunosuppression possibly induced by corticosteroids. Concurrent low-dose cyclophosphamide, appealing for its immunomodulatory effects, could also impact safety. In a retrospective case-control study, we evaluated the effect of systemic corticosteroid use in cancer patients receiving oncolytic virotherapy. Four treatment groups were identified: (1) oncolytic adenovirus with oral glucocorticoids, (2) virus alone, (3) virus with glucocorticoids and cyclophosphamide and (4) virus with cyclophosphamide. Adverse events, neutralizing antibody titers, viral DNA in circulation and tumor responses were evaluated. The most common adverse effects were grade 1-2 fatigue, nausea, fever and abdominal pain. Common asymptomatic findings included self-limiting grade 1-3 hyponatremia and aspartate aminotransferase increase. Safety was good and no significant differences were observed between the groups. All patients had an increase in neutralizing antibody titers post-treatment, and no trends for differences between groups were observed. There were fewer post-treatment virus genomes circulating in patients receiving glucocorticoids when compared to their control groups. Overall, glucocorticoid use in cancer patients receiving oncolytic adenovirus, with or without low-dose cyclophosphamide, seems safe.

Combinatorial treatment of non-small-cell lung cancers with gefitinib and Ad.mda-7 enhances apoptosis-induction and reverses resistance to a single therapy

Activation of the epidermal growth factor receptor (EGFR) contributes to the pathogenesis of non-small-cell lung carcinomas (NSCLC) and gefitinib, a selective reversible EGFR inhibitor, is effective in treating patients with NSCLC. However, clinical resistance to gefitinib is a frequent occurrence highlighting the need for improved therapeutic strategies. Melanoma differentiation associated gene-7 (mda-7)/Interleukin-24 (IL-24) (mda-7/IL-24) displays cancer-selective apoptosis induction when delivered via a replication-incompetent adenovirus (Ad.mda-7). In this study, the effect of Ad.mda-7 infection, either alone or in combination with gefitinib, was analyzed in a panel of NSCLC cell lines carrying wild-type EGFR (H-460 and H-2030) or mutant EGFR (H-1650 and H-1975). While H-2030 and H-1650 cells were sensitive, H-460 and H-1975 cells were resistance to growth inhibition by Ad.mda-7, which was reversed by the combination of Ad.mda-7 and gefitinib. This combination increased MDA-7/IL-24 and downstream effector double-stranded RNA-activated protein kinase (PKR) protein expression, promoting apoptosis induction of NSCLC cells. Inhibition of PKR significantly inhibited apoptosis induction by Ad.mda-7 when administered alone but not when used in combination with gefitinib. The combination treatment also augmented inhibition of EGFR signaling. Our findings indicate that a combinatorial treatment with Ad.mda-7 and gefitinib may provide benefit in the treatment of NSCLC, especially in patients displaying resistance to clinically used EGFR inhibitors.

Therapeutic ultrasound optimization for gene delivery: A key factor achieving nuclear DNA localization

When applying therapeutic-ultrasound (TUS) for gene-delivery, there is a great need to understand the contribution of different parameters to the transfection process. The aim of this study is to optimize a wide range of parameters associated with the TUS system concurrent with parameters associated with the transfection, achieving high transfection level and efficiency (total number of cells), while localizing the DNA in the nucleus. Exposure of different cell-types (BHK, LNCaP, BCE) to TUS resulted in high gene expression (1200 fold) and efficiency (28%) with minimal loss in cell viability (<20%). The optimal transfection level and efficiency was achieved using TUS at 2 W/cm2 (0.159 MPa), 30% duty cycle (DC) for 30 min (1080 J/cm2), by placing the transducer above the cells. Long-term TUS application was found to overcome the rate-limiting step of this technology-driving DNA to the cell nucleus. The effect of cell density and DNA concentrations were studied. Increasing DNA concentration contributes to the increase in total gene expression, but not necessarily to transfection efficiency. Our findings support the feasibility of TUS to deliver genes to cells and contribute to the understanding of wide range of parameters that affect the capability of TUS to efficiently deliver genes.

Sulindac enhances adenoviral vector expressing mda-7/IL-24–mediated apoptosis in human lung cancer

Several studies have shown antitumor activities of the melanoma differentiation–associated gene 7 (mda-7) and the nonsteroidal anti-inflammatory drug sulindac when used as a monotherapies against a wide variety of human cancers. However, the combined effects of mda-7 and sulindac have not previously been tested. Therefore, we tested the antitumor activity of an adenoviral vector expressing mda-7 (Ad-mda7) in combination with sulindac against non–small cell lung cancer cells in vitro and in vivo. When treated with Ad-mda7 in combination with sulindac, human lung cancer cells (A549 and H1299) underwent growth suppression resulting in apoptosis. The growth inhibition induced by Ad-mda7 in combination with sulindac was significantly greater than that observed with Ad-mda7 or sulindac alone. Furthermore, the degree of growth inhibition induced using this combination was dose-dependent for sulindac. Treatment with Ad-mda7 in combination with sulindac had no growth inhibitory effects on human normal lung (CCD-16) fibroblasts. We then investigated the mechanism by which sulindac enhances Ad-mda7-mediated apoptosis. Sulindac increased expression of ectopic MDA-7 protein in tumor cells, thereby increasing the expression of downstream effectors RNA-dependent protein kinase, p38MAPK, caspase-9, and caspase-3 and enhancing apoptosis of non–small cell lung cancer cells. Pulse-chase experiments showed that the increased expression of MDA-7 protein in sulindac-treated cells was due to increased half-life of the MDA-7 protein. Finally, treatment of human lung tumor xenografts in nude mice with Ad-mda7 plus sulindac significantly suppressed growth (P = 0.001) compared with Ad-mda7 or sulindac alone. Our results show for the first time that combined treatment with Ad-mda7 plus sulindac enhances growth inhibition and apoptosis of human lung cancer cells. The increased antitumor activity observed with the combination treatment is a result of increased half-life of MDA-7 protein. Regulation of protein turnover is a heretofore-unrecognized mechanism of this nonsteroidal anti-inflammatory drug.

Gene silencing in alveolar type II cells using cell-specific promoter in vitro and in vivo

RNA interference (RNAi) is a sequence-specific post-transcriptional gene silencing process. Although it is widely used in the loss-of-function studies, none of the current RNAi technologies can achieve cell-specific gene silencing. The lack of cell specificity limits its usage in vivo. Here, we report a cell-specific RNAi system using an alveolar epithelial type II cell-specific promoter--the surfactant protein C (SP-C) promoter. We show that the SP-C-driven small hairpin RNAs specifically depress the expression of the exogenous reporter (enhanced green fluorescent protein) and endogenous genes (lamin A/C and annexin A2) in alveolar type II cells, but not other lung cells, using cell and organ culture in vitro as well as in vivo. The present study provides an efficient strategy in silencing a gene in one type of cell without interfering with other cell systems, and may have a significant impact on RNAi therapy.

Combination of TRAIL gene therapy and chemotherapy enhances antitumor and antimetastasis effects in chemosensitive and chemoresistant breast cancers

We recently found that breast cancer cell lines that are resistant to chemotherapy or to the recombinant TRAIL protein are susceptible to TRAIL gene therapy. However, it is unclear whether a combination of TRAIL gene therapy and chemotherapy will have enhanced antitumor activity or can be used for the treatment of metastasis. In this study, we investigated the combined effect of TRAIL gene therapy and chemotherapeutic agents, including doxorubicin, paclitaxel, vinorelbine, gemcitabine, irinotecan, and floxuridine, in different breast cancer cell lines. In all the cell lines tested, including a breast cancer cell line that is resistant to chemotherapy, the combination of TRAIL gene therapy and cytotoxic agents had either a synergistic or an additive effect. An in vivo study showed that aerosolized administration of an adenovector expressing the GFP-TRAIL fusion protein from the human telomerase reverse transcriptase promoter (designated Ad/gTRAIL) also decreased the number of lung metastases from both doxorubicin-sensitive and doxorubicin-resistant breast cancer cell lines. The combination of TRAIL gene therapy and chemotherapy resulted in a further reduction of lung metastatic nodules with minimal toxicity. These results suggest that a combination of TRAIL gene therapy and chemotherapy is effective in the treatment of metastatic diseases.