The current state of head and neck cancer gene therapy

In vitro and in vivo anti-tumor activity of Coenzyme Q0 against TWIST1-overexpressing HNSCC cells: ROS-mediated inhibition of EMT/metastasis and autophagy/apoptosis induction

HNSCC (Head and Heck Squamous Cell Carcinoma) is a reasonably prevalent cancer with a high mortality rate. In this study, we tried to examine the anti-metastasis and apoptosis/autophagy actions of Coenzyme Q₀ (CoQ₀, 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a derivative of Antrodia camphorata in HNCC TWIST1 overexpressing (FaDu-TWIST1) cells as well as in vivo tumor xenograft mice model. Using fluorescence based cellular assays, western blot and nude mice tumor xenografts, we determined that CoQ₀ effectively reduced cell viability and displayed rapid morphological changes in FaDu-TWIST1 cells compared to FaDu cells. Non/sub-cytotoxic concentrations of CoQ₀ treatment reduces the cell migration by downregulating TWIST1 and upregulating E-cadherin. Apoptosis produced by CoQ₀ was mostly related with caspase-3 activation, PARP cleavage, and VDAC-1 expression. The FaDu-TWIST1 cells treated with CoQ₀ exhibits autophagy-mediated LC3-II accumulation and acidic vesicular organelles (AVOs) formation. Pre-treatment with 3-MA and CoQ effectively prevented CoQ₀-induced cell death and CoQ₀-triggered autophagy in FaDu-TWIST cells as a death mechanism. CoQ₀ induces ROS production in FaDu-TWIST1 cells and NAC pre-treatment significantly reduces anti-metastasis, apoptosis, and autophagy. Likewise, ROS-mediated AKT inhibition regulates CoQ₀-induced apoptosis/autophagy in FaDu-TWIST1 cells. In vivo studies exhibit, CoQ₀ effectively delays and reduces the tumor incidence and burden in FaDu-TWIST1-xenografted nude mice. Current findings display, CoQ₀ exhibits a novel anti-cancer mechanism hence, it might be appropriate for anticancer therapy, and a new potent drug for HNSCC.

PCR Detection of Epstein-Barr Virus (EBV) DNA in Patients with Head and Neck Squamous Cell Carcinoma, in Patients with Chronic Tonsillitis, and in Healthy Individuals

Epstein-Barr virus (EBV) is a common virus worldwide that is an etiologic agent in the development of many diseases, including cancer. Recent reports have shown the association of EBV with tumorigenesis in head and neck squamous cell carcinoma (HNSCC). Moreover, EBV has been reported to be present in tonsillar tissues, which suggests a close relationship between viral infections and tonsillar diseases, including chronic tonsillitis. The aim of the study was to analyze the prevalence of EBV DNA in 86 patients with HNSCC, in 70 patients with chronic tonsillitis, and in 144 healthy individuals (control group) and the associations between EBV infection and clinicopathological and demographic characteristics and the use of stimulants in all study groups. The objective of this study was also to analyze the prevalence of coinfection with human papillomavirus (HPV). After prior DNA isolation, EBV detection was performed using an EBV kit by real-time polymerase chain reaction. The prevalence of EBV infection in patients with HNSCC, patients with chronic tonsillitis, and the control group was 47.7%, 60%, and 24.3%, respectively. Compared to controls, a significantly higher prevalence of EBV in patients with chronic tonsillitis and HNSCC may suggest that EBV is a potential risk factor. No association was found between EBV infection and demographic or clinical data. Further studies are warranted due to inconclusive reports that were mainly related to geographic distribution, sample type, and detection technique. Considering the prevalence of the virus and the risk of serious diseases, attention should be paid to screening diagnosis and prevention of the infection.

Ultrasound-Targeted Microbubble Destruction Mediated si-CyclinD1 Inhibits the Development of Hepatocellular Carcinoma via Suppression of PI3K/AKT Signaling Pathway

Background and Aim

In our study, we aimed to investigate the effect of ultrasound-targeted microbubble destruction (UTMD)mediated si-CyclinD1 (CCND1) on the growth of hepatocellular carcinoma (HCC) cells.

Patients and Methods

Bioinformatics analysis was performed to detect the difference of CCND1 expression of HCC and normal liver tissues. After treatment with UTMDmediated si-CCND1, the growth and apoptosis of HepG2 cells were detected by flow cytometry, MTT, EdU staining, colony formation assay, Hoechst 33,258 staining and Western blot analysis. The growth of HepG2 cells in vivo was also studied via xenograft tumor in nude mice.

Results

CCND1 was highly expressed in HCC tissues and HCC cell lines. UTMDmediated si-CCND1 could inhibit the growth of HepG2 cells and promote apoptosis via suppression of the PI3K/AKT signaling pathway. UTMDmediated si-CCND1 could also suppress the growth of HepG2 cells in vivo.

Conclusion

Our study provided evidence that UTMDmediated si-CCND1 could inhibit the growth of HepG2 cells and promote apoptosis via suppression of the PI3K/AKT signaling pathway.

Suppression of migration, invasion, and metastasis of cisplatin-resistant head and neck squamous cell carcinoma through IKKβ inhibition

We explored the role of the transcription factor, NF-κB, and its upstream kinase IKKβ in regulation of migration, invasion, and metastasis of cisplatin-resistant head and neck squamous cell carcinoma (HNSCC). We showed that cisplatin-resistant HNSCC cells have a stronger ability to migrate and invade, as well as display higher IKKβ/NF-κB activity compared to their parental partners. Importantly, we found that knockdown of IKKβ, but not NF-κB, dramatically impaired cell migration and invasion in these cells. Consistent with this, the IKKβ inhibitor, CmpdA, also inhibited cell migration and invasion. Previous studies have already shown that N-Cadherin, an epithelial-mesenchymal transition (EMT) marker, and IL-6, a pro-inflammatory cytokine, play important roles in regulation of HNSCC migration, invasion, and metastasis. We found that cisplatin-resistant HNSCC expressed higher levels of N-Cadherin and IL-6, which were significantly inhibited by CmpdA. More importantly, we showed that CmpdA treatment dramatically abated cisplatin-resistant HNSCC cell metastasis to lungs in a mouse model. Our data demonstrated the crucial role of IKKβ in control of migration, invasion, and metastasis, and implicated that targeting IKKβ may be a potential therapy for cisplatin-resistant metastatic HNSCC.

Biomarkers in Head and Neck Cancer an Update

The study is aimed at establishing the purpose of tumour markers, their application, classification, diagnostic and therapeutic roles in the management of head and neck cancer. A literature review using Medline, Scopus, Google Scholar, the Cochrane Database of Systematic Reviews and the Cochrane central register of controlled trials for articles published between 1993 and 2016 on tumour markers and their role in head and neck cancer was performed. A broader search of prognostic markers in head and neck cancer was also carried out to avoid missing other pertinent markers. Natural history, tumour biology, stage and prognostic factors influence the outcome of management in patients with Head and Neck Squamous cell carcinoma (HNSCC). Evaluation of the cellular lineage and histogenic origin of diverse neoplasms can be done using tumour biomarkers. Identifying predictive tumour markers can lead to improvement in preventive management of HNSCC. There has been remarkable advancement in molecular technology with gene expression and proteomic profiling. Integration of specific tumour markers into routine clinical practice requires substantiation through well designed clinical trials. The investigation of tumour markers is imperative as they influence the prognosis of HNSCC and provide the potential to improve outcomes of treatment through targeted therapy. We have outlined recent tumour biomarkers in this review which have significant role in diagnosis, screening and prognostication in HNSCC. Recent advancement in clinical applications, therapeutic strategies of tumour markers has been highlighted.

The Evolving Landscape of Gene Therapy in Plastic Surgery

With the rapid rise of personalized genomic sequencing and clustered regularly interspaced short palindromic repeat (CRISPR) technology, previous gaps in gene therapy are beginning to be bridged, paving the way for increasing clinical applicability. This article aims to provide an overview of the fundamentals of gene therapy and discuss future potential interventions relevant to plastic surgeons. These interventions include enhancing tissue regeneration and healing, as well as modifying disease processes in congenital anomalies. Though clinical applications are still on the horizon, a deeper understanding of these new advances will help plastic surgeons understand the current landscape of gene therapy and stay abreast of future opportunities.

Regulation of cisplatin-resistant head and neck squamous cell carcinoma by the SRC/ETS-1 signaling pathway

BACKGROUND

We investigated the role of the ETS-1 transcription factor in Head and Neck Squamous Cell Carcinoma (HNSCC) in multiple cisplatin-resistant HNSCC cell lines.

METHODS

We examined its molecular link with SRC and MEK/ERK pathways and determined the efficacy of either MEK/ERK inhibitor PD0325901 or SRC inhibitor Dasatinib on cisplatin-resistant HNSCC inhibition.

RESULTS

We found that ETS-1 protein expression levels in a majority of cisplatin-resistant HNSCC cell types were higher than those in their parental cisplatin sensitive partners. High ETS-1 expression was also found in patient-derived, cisplatin-resistant HNSCC cells. While ETS-1 knockdown inhibited cell proliferation, migration, and invasion, it could still re-sensitize cells to cisplatin treatment. Interestingly, previous studies have shown that MER/ERK pathways could regulate ETS-1 through its phosphorylation at threonine 38 (T38). Although almost all cisplatin-resistant HNSCC cells we tested showed higher ETS-1 phosphorylation levels at T38, we found that inhibition of MEK/ERK pathways with the MEK inhibitor PD0325901 did not block this phosphorylation. In addition, treatment of cisplatin-resistant HNSCC cells with the MEK inhibitor completely blocked ERK phosphorylation but did not re-sensitize cells to cisplatin treatment. Furthermore, we found that, consistent with ETS-1 increase, SRC phosphorylation dramatically increased in cisplatin-resistant HNSCC, and treatment of cells with the SRC inhibitor, Dasatinib, blocked SRC phosphorylation and decreased ETS-1 expression. Importantly, we showed that Dasatinib, as a single agent, significantly suppressed cell proliferation, migration, and invasion, in addition to survival.

CONCLUSIONS

Our results demonstrate that the SRC/ETS-1 pathway plays a crucial role and could be a key therapeutic target in cisplatin-resistant HNSCC treatment.

Folate-Decorated Polyamidoamine Dendrimer Nanoparticles for Head and Neck Cancer Gene Therapy

Gene delivery systems have been developed on the basis of dendrimers and many other types of nanoparticle carriers, but few have been developed for head and neck squamous cell carcinomas (HNSCC). Herein, we describe the design and synthesis of fluorescently labeled, folic acid-decorated polyamidoamine (PAMAM) generation 4 (G4) dendrimer conjugates for HNSCC-targeted gene delivery. This delivery system comprises a dendrimer as the carrier that is conjugated with folic acid (FA) as HNSCC targeting moiety and imaging agents fluorescein isothiocyanate (FITC) or IRDye 800CW (NIR) for in vitro trafficking or bioimaging, respectively. By complexing with plasmid or siRNA, G4-FA/plasmid (or siRNA) significantly enhances gene transfection or knockdown efficiency in HNSCC cells. In a mouse xenograft model of HNSCC, this versatile G4-FA vector shows high biocompatibility, tumor targeting, high uptake, and sustained retention, making it a suitable platform for HNSCC gene therapy.

Co-targeting EGFR and IKKβ/NF-κB signalling pathways in head and neck squamous cell carcinoma: a potential novel therapy for head and neck squamous cell cancer

Background

Epidermal growth factor receptor (EGFR) plays an important role in head and neck squamous cell carcinoma (HNSCC) proliferation and therapy resistance, but the efficacy of targeting of EGFR for therapy has been limited. Here, we explore the molecular link between EGFR and inhibitor of κB kinase β/nuclear factor-κB (IKKβ/NF-κB) signalling pathways in the regulation of HNSCC EGFR inhibitor resistance.

Methods

We performed in vitro experiments in eight human HNSCC cell lines and a patient-derived HNSCC cell line as well as in vivo xenografts in a human HNSCC cell line.

Results

We found that treatment of all HNSCC cells with Gefitinib and Erlotinib, two Food Drug Administration-approved EGFR inhibitors, blocked the activity of Akt/mammalian target of the rapamycin (mTOR) and extracellular signal-regulated kinase, two crucial downstream effectors of EGFR, but up-regulated IKKβ/NF-κB signalling. In addition, induction of IKKβ/NF-κB by EGFR inhibitors required HER2 and HER3 expression. In keeping with these, IKKβ inhibitor CmpdA synergistically enhanced the efficacy of EGFR inhibitors to further inhibit in vitro HNSCC cell growth. Importantly, we demonstrated that the combination of Gefitinib with CmpdA inhibited xenograft tumour formation.

Conclusion

Our data demonstrated that co-targeting EGFR and IKKβ with Gefitinib and IKKβ inhibitors could provide a potential novel therapy for head and neck squamous cell cancer.

Anti-colorectal cancer effects of anti-p21Ras scFv delivered by the recombinant adenovirus KGHV500 and cytokine-induced killer cells

BACKGROUND

Colorectal cancer (CRC) is the most common type of gastrointestinal cancer. CRC gene therapy mediated by adenovirus holds great promise for the treatment of malignancies. However, intravenous delivery of adenovirus exhibits limited anti-tumor activity in vivo when used alone.

METHODS

In this study, the antitumor activity of the recombinant adenovirus KGHV500 was assessed with the MTT, TUNEL, Matrigel invasion and cell migration assays. To enhance the intravenous delivery of KGHV500 in vivo, cytokine-induced killer (CIK) cells were used as a second vector to carry KGHV500. We explored whether CIK cells could carry the recombinant adenovirus KGHV500 containing the anti-p21Ras single chain fragment variable antibody (scFv) gene into tumors and enhance antitumor potency.

RESULTS

Our results showed that KGHV500 exhibited significant antitumor activity in vitro. In the nude mouse SW480 tumor xenograft model, the combination of CIK cells with KGHV500 could induce higher antitumor activity against colorectal cancer in vivo than that induced by either CIK or KGHV500 alone. After seven days of treatment, adenovirus and scFv were detected in tumor tissue but were not detected in normal tissues by immunohistochemistry. Therefore, KGHV500 replicates in tumors and successfully expresses anti-p21Ras scFv in a colorectal cancer xenograft model.

CONCLUSIONS

Our study provides a novel strategy for the treatment of colorectal cancer by combining CIK cells with the recombinant adenovirus KGHV500 which carried anti-p21 Ras scFv.

Gene Therapy in Head and Neck Cancer

Although overall cancer death rates are decreasing, comparative improvements in head and neck squamous cell cancer are modest. Although new advances targeting immune checkpoints may soon improve these numbers, additional research for new therapeutic options is vital. One potential treatment avenue is the use of gene therapy. This article provides insight into some gene therapy targets and varied techniques being evaluated for patients with head and neck cancer. Techniques include corrective gene therapy, cytoreductive gene therapy, and gene editing, in addition to a discussion on gene therapy vectors.

Survivin-Based Treatment Strategies for Squamous Cell Carcinoma

Survivin, an anti-apoptotic molecule abundantly expressed in most human neoplasms, has been reported to contribute to cancer initiation and drug resistance in a wide variety of human tumors. Efficient downregulation of survivin can sensitize tumor cells to various therapeutic interventions, generating considerable efforts in its validation as a new target in cancer therapy. This review thoroughly analyzes up-to-date information on the potential of survivin as a therapeutic target for new anticancer treatments. The literature dealing with the therapeutic targeting of survivin will be reviewed, discussing specifically squamous cell carcinomas (SCCs), and with emphasis on the last clinical trials. This review gives insight into the recent developments undertaken in validating various treatment strategies that target survivin in SCCs and analyze the translational possibility, identifying those strategies that seem to be the closest to being incorporated into clinical practice. The most recent developments, such as dominant-negative survivin mutants, RNA interference, anti-sense oligonucleotides, small-molecule inhibitors, and peptide-based immunotherapy, seem to be helpful for effectively downregulating survivin expression and reducing tumor growth potential, increasing the apoptotic rate, and sensitizing tumor cells to chemo- and radiotherapy. However, selective and efficient targeting of survivin in clinical trials still poses a major challenge.

hTERT C250T promoter mutation and telomere length as a molecular markers of cancer progression in patients with head and neck cancer

Squamous cell carcinoma of the head and neck (HNSCC) is the sixth leading cause of cancer worldwide, representing over half a million incidents every year. Cancer cells, including HNSCC, are characterized by increased telomerase activity. This enzymatic complex is active in ~90% of all cancer types and is responsible for the lengthening of telomeres. Highly recurrent point mutations in the human telomerase reverse transcriptase (hTERT) promoter have recently been reported in a number of human neoplasms. The aim of the present study was to analyze the prevalence of the hTERT promoter C250T mutation and telomere length in the blood leukocytes of 61 patients with HNSCC and 49 healthy individuals. Quantitative polymerase chain reaction identified the hTERT promoter mutation in 36% of patients with HNSCC. To the best of our knowledge this is first report indicating the presence of shorter telomeres in early stage tumors. In addition, the results suggest that the C250T hTERT promoter mutation and telomere length assessment may serve as important molecular markers of HNSCC progression.

Clinical value of monoclonal antibodies and tyrosine kinase inhibitors in the treatment of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of malignant tumours that affects over 500,000 patients per year. Treatment failure is generally due to the heterogeneity of these tumours and to the serious adverse effects associated with treatment. Immunological system impairment, which is common in HNSCC, further contributes to treatment failure by mediating tumour escape mechanisms. To date, the only clinically approved targeted therapy agent is cetuximab, a monoclonal antibody (mAb) that binds to, and inhibits, epidermal growth factor receptor, which is widely overexpressed in HNSCC. Cetuximab has been proven to induce antibody-dependent cellular cytotoxicity, further magnifying its therapeutic effect. DNA sequencing of HNSCC cells has identified the presence of mutated genes, thus making their protein products potential targets for therapeutic inhibition. Immune mechanisms have been found to have a significant impact on carcinogenesis, thus providing the rationale to support efforts to identify anticancer compounds with immunomodulatory properties. In the context of the rapid development of novel targeted agents, the aim of the present paper is to review our current understanding of HNSCC and to review the novel anticancer agents (mAbs and TKIs) introduced in recent years, including an assessment of their efficacy and mechanisms of action.

A nonviral vector with transfection activity comparable with adenoviral transduction

AIM

Viral vectors are used commonly in gene therapy trials, but their potential toxic effects are a serious concern. Identification of highly efficient nonviral vectors may alleviate these effects. Results & methodology: We compared the abilities of TransfeX, TransIT-LT1 and adenovirus to deliver the firefly luciferase and green fluorescent protein genes into HeLa cervical carcinoma, and HSC-3 and H357 oral squamous cell carcinoma cells. TransfeX mediated fourfold higher gene expression in HeLa cells than adenovirus, even at the highest multiplicity of infection. Flow cytometry indicated that a population of transfected cells expresses higher levels of green fluorescent protein than transduced cells.

CONCLUSION

TransfeX may be useful for gene therapy applications, particularly where the use of adenovirus is contraindicated.

Folic acid-decorated polyamidoamine dendrimer mediates selective uptake and high expression of genes in head and neck cancer cells

AIM

Folic acid (FA)-decorated polyamidoamine dendrimer G4 (G4-FA) was synthesized and studied for targeted delivery of genes to head and neck cancer cells expressing high levels of folate receptors (FRs).

METHODS

Cellular uptake, targeting specificity, cytocompatibility and transfection efficiency were evaluated.

RESULTS

G4-FA competes with free FA for the same binding site. G4-FA facilitates the cellular uptake of DNA plasmids in a FR-dependent manner and selectively delivers plasmids to FR-high cells, leading to enhanced gene expression.

CONCLUSION

G4-FA is a suitable vector to deliver genes selectively to head and neck cancer cells. The fundamental understandings of G4-FA as a vector and its encouraging transfection results for head and neck cancer cells provided support for its further testing in vivo.

RNA interference in head and neck oncology

Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cause of cancer worldwide. The treatment of choice in case of head and neck cancer is surgery, followed by chemo- or/and radiotherapy. A potentially effective instrument to improve the outcome of numerous diseases, including viral infections, diabetes and cancer, is RNA interference (RNAi). It has been demonstrated that small interfering RNA and microRNA molecules are strongly involved in the regulation of various different pathological processes in cancer development. RNAi has become a valuable research tool allowing a better understanding of the mechanisms regulating cancer pathogenesis. Considering those advantages over other current therapeutics (including specificity and high efficacy), RNAi appears to be a potentially useful tool in cancer treatment. The present review discusses the current knowledge about the possibility of using RNAi in HNSCC therapy.

The antitumor efficacy of a novel adenovirus-mediated anti-p21Ras single chain fragment variable antibody on human cancers in vitro and in vivo

Activated ras genes are found in a large number of human tumors, and therefore are one of important targets for cancer therapy. This study investigated the antitumor effects of a novel single chain fragment variable antibody (scFv) against ras protein, p21Ras. The anti-p21Ras scFv gene was constructed by phage display library from hybridoma KGHR1, and then subcloned into replication-defective adenovirus vector to obtain recombinant adenovirus KGHV100. Human tumor cell lines with high expression of p21Ras SW480, MDA-MB‑231, OVCAR-3, BEL-7402, as well as tumor cell line with low expression of p21Ras, SKOV3, were employed to investigate antitumor effects in vitro and in vivo. Fluorescence microscopy demonstrated that KGHV100 was able to express intracellularly anti-p21Ras scFv antibody in cultured tumor cells and in transplantation tumor cells. MTT, Transwell, colony formation, and flow cytometry analysis showed that KGHV100 led to significant growth arrest in tumor cells with high p21Ras expression, and induced G0/G1 cell cycle arrest in the studied tumor cell lines. In vivo, KGHV100 significantly inhibited tumor growth following intratumoral injection, and the survival rates of the mice were higher than the control group. These results indicate that the adenovirus-mediated intracellular expression of the novel anti-p21Ras scFv exerted strong antitumoral effects, and may be a potential method for therapy of cancers with p21Ras overexpression.

Sendai virus-mediated gene transfer of the c-myc suppressor far-upstream element-binding protein-interacting repressor suppresses head and neck cancer

Far-upstream element-binding protein-interacting repressor (FIR) is a transcription factor that inhibits c-Myc expression and has been shown to have antitumor effects in some malignancies. Here, we evaluated the antitumor effects of FIR using fusion gene-deleted Sendai virus (SeV/ΔF) as a nontransmissible vector against head and neck squamous cell carcinoma (HNSCC). Using in vitro and in vivo xenograft mouse models, we observed efficient expression of green fluorescent protein (GFP) following transduction with the SeV/ΔF vector encoding GFP (GFP-SeV/ΔF) into HNSCC cells. In vitro and in vivo studies revealed that administration of the FIR-encoded SeV/ΔF (FIR-SeV/ΔF) vector exerted significant antitumor effects, suppressed c-Myc expression and induced apoptosis in HNSCC. Additionally, the antitumor effects of FIR or the expression of GFP following administration of the FIR- or GFP-SeV/ΔF vector, respectively, were dependent on the multiplicity of infection or titer. Furthermore, the SeV/ΔF vector itself had no cytotoxic effects. Therefore, the SeV/ΔF vector may be safe and useful for the treatment of HNSCC, allowing for high-titer SeV/ΔF vector administration for anticancer gene therapy. In addition, SeV/ΔF vector-mediated FIR gene therapy demonstrated effective tumor suppression in HNSCC, suggesting that this therapy may have the potential for clinical use as a novel strategy for HNSCC treatment.

Gene therapy for cardiovascular disease mediated by ultrasound and microbubbles

Gene therapy provides an efficient approach for treatment of cardiovascular disease. To realize the therapeutic effect, both efficient delivery to the target cells and sustained expression of transgenes are required. Ultrasound targeted microbubble destruction (UTMD) technique has become a potential strategy for target-specific gene and drug delivery. When gene-loaded microbubble is injected, the ultrasound-mediated microbubble destruction may spew the transported gene to the targeted cells or organ. Meanwhile, high amplitude oscillations of microbubbles increase the permeability of capillary and cell membrane, facilitating uptake of the released gene into tissue and cell. Therefore, efficiency of gene therapy can be significantly improved. To date, UTMD has been successfully investigated in many diseases, and it has achieved outstanding progress in the last two decades. Herein, we discuss the current status of gene therapy of cardiovascular diseases, and reviewed the progress of the delivery of genes to cardiovascular system by UTMD.

Current status of gene therapy for brain tumors

Glioblastoma (GBM) is the most common and deadliest primary brain tumor in adults, with current treatments having limited impact on disease progression. Therefore the development of alternative treatment options is greatly needed. Gene therapy is a treatment strategy that relies on the delivery of genetic material, usually transgenes or viruses, into cells for therapeutic purposes, and has been applied to GBM with increasing promise. We have included selectively replication-competent oncolytic viruses within this strategy, although the virus acts directly as a complex biologic anti-tumor agent rather than as a classic gene delivery vehicle. GBM is a good candidate for gene therapy because tumors remain locally within the brain and only rarely metastasize to other tissues; the majority of cells in the brain are post-mitotic, which allows for specific targeting of dividing tumor cells; and tumors can often be accessed neurosurgically for administration of therapy. Delivery vehicles used for brain tumors include nonreplicating viral vectors, normal adult stem/progenitor cells, and oncolytic viruses. The therapeutic transgenes or viruses are typically cytotoxic or express prodrug activating suicide genes to kill glioma cells, immunostimulatory to induce or amplify anti-tumor immune responses, and/or modify the tumor microenvironment such as blocking angiogenesis. This review describes current preclinical and clinical gene therapy strategies for the treatment of glioma.

MEN1 gene replacement therapy reduces proliferation rates in a mouse model of pituitary adenomas

Multiple endocrine neoplasia type 1 (MEN1) is characterized by the combined occurrence of pituitary, pancreatic, and parathyroid tumors showing loss of heterozygosity in the putative tumor suppressor gene MEN1. This gene encodes the protein menin, the overexpression of which inhibits cell proliferation in vitro. In this study, we conducted a preclinical evaluation of MEN1 gene therapy in pituitary tumors of Men1(+/-) mice, using a recombinant nonreplicating adenoviral serotype 5 vector that contained the murine Men1 cDNA under control of a cytomegalovirus promoter (Men1.rAd5). Pituitary tumors in 55 Men1(+/-) female mice received a transauricular intratumoral injection of Men1.rAd5 or control treatments, followed by 5-bromo-2-deoxyuridine (BrdUrd) in drinking water for four weeks before magnetic resonance imaging (MRI) and immunohistochemical analysis. Immediate procedure-related and 4-week mortalities were similar in all groups, indicating that the adenoviral gene therapy was not associated with a higher mortality. Menin expression was higher in the Men1.rAd5-treated mice when compared with other groups. Daily proliferation rates assessed by BrdUrd incorporation were reduced significantly in Men1.rAd5-injected tumors relative to control-treated tumors. In contrast, apoptotic rates, immune T-cell response, and tumor volumes remained similar in all groups. Our findings establish that MEN1 gene replacement therapy can generate menin expression in pituitary tumors, and significantly reduce tumor cell proliferation.

A feasibility study on gene therapy of pancreatic carcinoma with Ad-PUMA

Pancreatic cancer is one of the most malignant tumors with high mortality and poor prognosis even with the aggressive conventional therapies. Biotherapy based on the understanding of tumorigenesis mechanism is ongoing to improve the outcomes of cancer patients. We sought here to evaluate the therapeutic potential of a proapoptotic gene, PUMA, in pancreatic cancer. We found that PUMA was differently expressed in a series of pancreatic ductal adenocarcinoma cancer cell lines, and adenovirus-mediated expression of PUMA (Ad-PUMA) in these cells resulted in massive apoptosis. PUMA was more potent than p53 in suppressing growth of cancer cells. RT-PCR and Western Blot revealed that exogenous PUMA was expressed 6 h after Ad-PUMA infection. Furthermore, we assessed the efficacy of Ad-PUMA combining anticancer drugs (5-fluorouracil, cisplatin, gemcitabine hydrochloride, respectively) in these pancreatic cancer cell lines. Data revealed that PUMA significantly sensitized pancreatic carcinoma cell lines to chemotherapeutics, which may be resulted from abundant apoptosis induction. In nude mice with PANC-1 xenografts, Ad-PUMA treatment significantly inhibited the tumor growth. These results suggest that PUMA is a potent molecular tool in suppressing tumor growth sensitizing pancreatic carcinoma cells to chemical drugs. PUMA plays roles in negatively regulating cancer cell growth and may be a promising tool for cancer biotherapy, with or without combination with chemotherapeutic agents.

New developments and opportunities in oral mucosal drug delivery for local and systemic disease

The oral mucosa's accessibility, excellent blood supply, by-pass of hepatic first-pass metabolism, rapid repair and permeability profile make it an attractive site for local and systemic drug delivery. Technological advances in mucoadhesives, sustained drug release, permeability enhancers and drug delivery vectors are increasing the efficient delivery of drugs to treat oral and systemic diseases. When treating oral diseases, these advances result in enhanced therapeutic efficacy, reduced drug wastage and the prospect of using biological agents such as genes, peptides and antibodies. These technologies are also increasing the repertoire of drugs that can be delivered across the oral mucosa to treat systemic diseases. Trans-mucosal delivery is now a favoured route for non-parenteral administration of emergency drugs and agents where a rapid onset of action is required. Furthermore, advances in drug delivery technology are bringing forward the likelihood of transmucosal systemic delivery of biological agents.

Vesicular stomatitis virus matrix protein (VSVMP) inhibits the cell growth and tumor angiogenesis in oral squamous cell carcinoma

The purpose of this study was to investigate the anticancer property of vesicular stomatitis virus matrix protein (VSVMP) in oral squamous cell carcinoma (OSCC) via in vitro and in vivo approaches. In this study, we found that OSCC cells treated with VSVMP showed retarded cell growth in vitro. The percentage of apoptotic cells in VSVMP group was much higher than that of the control groups. Moreover, our in vivo experiments showed that the growth of tumor xenografts was significantly suppressed by VSVMP treatment without any obvious side effects. Further studies revealed that the suppression of tumor growth may be caused by the synergistic effect of VSVMP related cell apoptosis enhancing and tumor angiogenesis suppression, and the latter is most likely correlated with the suppression of VEGF pathway. This study indicated that VSVMP treatment can effectively inhibited the cell growth and tumor angiogenesis in OSCC without obvious adverse effects. Therefore, VSVMP might be a potential and efficient strategy for OSCC treatment.

Transient alteration of cellular redox buffering before irradiation triggers apoptosis in head and neck carcinoma stem and non-stem cells

Background

Head and neck squamous cell carcinoma (HNSCC) is an aggressive and recurrent malignancy owing to intrinsic radioresistance and lack of induction of apoptosis. The major focus of this work was to design a transient glutathione depleting strategy during the course of irradiation of HNSCC in order to overcome their radioresistance associated with redox adaptation.

Methodology/Principal Findings

Treatment of SQ20B cells with dimethylfumarate (DMF), a GSH-depleting agent, and L-Buthionine sulfoximine (BSO), an inhibitor of GSH biosynthesis 4 h before a 10 Gy irradiation led to the lowering of the endogenous GSH content to less than 10% of that in control cells and to the triggering of radiation-induced apoptotic cell death. The sequence of biochemical events after GSH depletion and irradiation included ASK-1 followed by JNK activation which resulted in the triggering of the intrinsic apoptotic pathway through Bax translocation to mitochondria.

Conclusions

This transient GSH depletion also triggered radiation-induced cell death in SQ20B stem cells, a key event to overcome locoregional recurrence of HNSCC. Finally, our in vivo data highlight the relevance for further clinical trials of endogenous redox modulation to enhance the cytotoxic effects of radiotherapy.

Spliceosome-mediated RNA trans-splicing facilitates targeted delivery of suicide genes to cancer cells

Patients suffering from recessive dystrophic epidermolysis bullosa (RDEB), a hereditary blistering disease of epithelia, show susceptibility to develop highly aggressive squamous cell carcinoma (SCC). Tumors metastasize early and are associated with mortality in the 30th-40th years of life in this patient group. So far, no adequate therapy is available for RDEB SCC. An approach is suicide gene therapy, in which a cell death-inducing agent is introduced to cancer cells. However, lack of specificity has constrained clinical application of this modality. Therefore, we used spliceosome-mediated RNA trans-splicing technology, capable of replacing a tumor-specific transcript with one encoding a cell death-inducing peptide/toxin, to provide tumor-restricted expression. We designed 3' pre-trans-splicing molecules (PTM) and evaluated their efficiency to trans-splice an RDEB SCC-associated target gene, the matrix metalloproteinase-9 (MMP9), in a fluorescence-based test system. A highly efficient PTM was further adapted to insert the toxin streptolysin O (SLO) of Streptococcus pyogenes into the MMP9 gene. Transfection of RDEB SCC cells with the SLO-PTM resulted in cell death and induction of toxin function restricted to RDEB SCC cells. Thus, RNA trans-splicing is a suicide gene therapy approach with increased specificity to treat highly malignant SCC tumors.