Current Gene Therapy (v.14, #2)

Tumor-Specific Delivery of Histidine-Rich Glycoprotein Suppresses Tumor Growth and Metastasis by Anti-angiogenesis and Vessel Normalization by Xiawei Cheng, Xiaoxin Zhang, Wei Cheng, Jianxiang Chen, Cailie Ma, Bingya Yang, Zi-Chun Hua (75-85).
Histidine-proline-rich glycoprotein (HPRG) is a plasma protein of vertebrates, which has potent antiangiogenicand tumor vessel normalization properties. Attenuated Salmonella Typhimurium strain VNP20009 preferentiallyaccumulates and replicates in hypoxic tumor regions. In this study, we engineered VNP20009 to express HPRG underthe control of a hypoxia-induced NirB promoter and evaluated the efficacy of the VNP20009-mediated targeted expressionofHPRG (VNP-pNHPRG) on tumor growth in primary and metastatic tumor models. When VNP-pNHPRG wasadministered to melanoma tumor mice by intraperitoneal injection, the NirB promoter controlled HPRG expression in tumor,which inhibited tumor vessel density and areas as well as regulated vascular normalization. VNP-pNHPRG significantlydelayed tumor growth and enhanced survival time in primary B16F10 mice model and markedly suppressed lungmetastatic tumor growth and prolonged survival time in B16F10 metastatic tumor models. Furthermore, VNP-pNHPRGdown-regulated the HIF-1α-VEGF/Ang-2 signal pathway by altering the hypoxic tumor microenvironment. These resultsshowed that VNP20009-mediated targeted expression of HPRG provides a novel cancer gene therapeutic approach for thetreatment of primary and metastatic cancer.

Basic Biology of Adeno-Associated Virus (AAV) Vectors Used in Gene Therapy by Balaji Balakrishnan, Giridhara R. Jayandharan (86-100).
Adeno-associated virus (AAV) based vectors have emerged as important tools for gene therapy in humans. Therecent successes seen in Phase I/II clinical trials have also highlighted the issues related to the host and vector-related immuneresponse that preclude the universal application of this promising vector system. A fundamental insight into the biologicalmechanisms by which AAV infects the host cell and a thorough understanding of the immediate and long-livedcellular responses to AAV infection is likely to offer clues and help design better intervention strategies to improve thetherapeutic efficiency of AAV vectors. This article reviews the biology of AAV-host cellular interactions and outlinestheir application in the development of novel and improved AAV vector systems.

Atoh1: Landscape for Inner Ear Cell Regeneration by Ren Hongmiao, Liu Wei, Hu Bing, Ding Da Xiong, Ren Jihao (101-111).
Hearing impairment is primarily attributed to inner ear hair cell (HC) defects that subsequently lead to spiralganglion neuron (SGN) loss. The HC loss cannot be self-repaired because of the HCs' limited capacity to regenerate inmammals. Atoh1, also known as Math1, Hath1, and Cath1, is a proneural basic helix-loop-helix (bHLH) transcriptionfactor that played a major role in HC differentiation. Atoh1 activity at various developmental stages can sufficiently driveHC differentiation in the cochlea. Recent issues of a certain publication have identified that Atoh1 is essential for inner eardevelopment, such as cell growth, morphogenesis, differentiation, cellular maintenance, and survival. We summarize thenew findings in Atoh1 research and identify the mechanisms underlying the role of Atoh1 in HC regeneration to launchthe future of Atoh1 therapy.

MicroRNA Pathways: An Emerging Role in Identification of Therapeutic Strategies by Soundararajan Vijayarathna, Chern E. Oon, Subramanion L. Jothy, Yeng Chen, Jagat R. Kanwar, Sreenivasan Sasidharan (112-120).
For years researchers have exerted every effort to improve the influential roles of microRNA (miRNA) in regulatinggenes that direct mammalian cell development and function. In spite of numerous advancements, many facets ofmiRNA generation remain unresolved due to the perplexing regulatory networks. The biogenesis of miRNA, eminentlyendures as a mystery as no universal pathway defines or explicates the variegation in the rise of miRNAs. Early evidencein biogenesis ignited specific steps of being omitted or replaced that eventuate in the individual miRNAs of differentmechanisms. Understanding the basic foundation concerning how miRNAs are generated and function will help with diagnostictools and therapeutic strategies. This review encompasses the canonical and the non-canonical pathways involvedin miRNA biogenesis, while elucidating how miRNAs regulate genes at the nuclear level and also the mechanism that liesbehind circulating miRNAs.

Gene Therapy: The Role of Cytoskeleton in Gene Transfer Studies Based on Biology and Mathematics by Maria G. Notarangelo, Roberto Natalini, Emanuela Signori (121-127).
Gene therapy is a promising approach for treating a wide range of human pathologies such as genetic disordersas well as diseases acquired over time. Viral and non-viral vectors are used to convey sequences of genes that can be expressedfor therapeutic purposes. Plasmid DNA is receiving considerable attention for intramuscular gene transfer due toits safety, simplicity and low cost of production. Nevertheless, strategies to improve DNA uptake into the nucleus of cellsfor its expression are required. Cytoskeleton plays an important role in the intracellular trafficking. The mechanism regulatingthis process must be elucidated. Here, we propose a new methodological approach based on the coupling of biologyassays and predictive mathematical models, in order to clarify the mechanism of the DNA uptake and its expression intothe cells. Once these processes are better clarified, we will be able to propose more efficient therapeutic gene transfer protocolsfor the treatment of human patients.

Effects of Angiopoietin-1 on Inflammatory Injury in Endothelial Progenitor Cells and Blood Vessels by Yi-Qing Wang, Jing-Jin Song, Xiao Han, Yi-Ye Liu, Xi-Huang Wang, Zhi-ming Li, Chi-Meng Tzeng (128-135).
Endothelial progenitor cells (EPCs) and angiopoietin-1 (Ang-1) play important roles in vasculogenesis and angiogenesis,respectively. Thus, targeting both aspects of cardiovascular tissue regeneration may offer promising therapeuticoptions for cardiovascular disorders. To this end, we constructed a lentiviral vector (pNL) with the Ang-1 gene andtransfected EPCs with it (Ang-1-EPCs) to investigate vasculogenesis in both cellular and animal models. Compared tocontrols, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) increased significantlyin both untreated EPCs and in the pNL vector group. After Ang-1 transcription, ICAM-1 and VCAM-1 decreasedconsiderably in those treatment groups. Ang-1-modified EPCs alleviated inflammatory responses induced by tumornecrosisfactor-α (TNF-α) in vitro. Moreover, Ang-1-EPC implantation inhibited neointimal hyperplasia after ballooncatheter injury in rats, dramatically diminishing the intimal-media (I/M) ratio and decreasing the neointimal area. Proliferatingcell nuclear antigen expression in the Ang-1-EPC group was lower than the EPC non-treatment group as well, suggestingthat Ang-1-EPC improved cell survival during inflammation and promoted endothelialization in damaged bloodvessels.

Purpose: Magnetic resonance imaging (MRI) has been used to track magnetically labeled human bone marrowderivedmesenchymal stem cells (hBMSCs) in vivo after COX-2 silencing and transplantation into nude rats via tail veininjection. Methods: In the present study, we knocked down COX-2 expression in hBMSCs through lentivirus transduction.The COX-2 knockdown was confirmed by real-time PCR and Western blotting analyses. Subsequently, we labeledcells with the novel reagent SPIO-Molday ION Rhodamine-B™ (MIRB). The viability, proliferation and differentiation ofthese cells were assessed in vitro. Labeled lenti-shCOX2 hBMSCs, unlabeled hBMSCs and phosphate-buffered saline(PBS) were individually injected into the tail veins of nude rat models, forming three treatment groups. All nude rats underwentGRE T2*-weighted MRI at 1 h, 7 days and 14 days post-injection. After MRI examination, the animals were sacrificed,and the brain and liver were examined by fluorescence microscopy and Prussian Blue staining. Results: Our resultsconfirmed the successful down-regulation of COX-2 at the mRNA and protein levels in hBMSCs by lentivirus transduction.The viability and differentiation of hBMSCs were not affected by MIRB labeling. After 7 days, hypointense signalvoid areas in the rat livers were observed on MRI. After 14 days, iron particles were detected in the blood vessels, sinusoids,interlobular septum and capsule tissues of the liver. Conclusion: The MIRB-labeled lenti-shCOX2 hBMSCstransplanted into nude rat models via tail vein injection can be detected and monitored in vivo using 3.0 T clinical MRI forup to 14 days after cell transplantation.