A non-invasive tissue-specific molecular delivery method of cancer gene therapy.

A Japanese word, monozukuri (literally translated "making things") is the philosophy of first having the idea and then the faith in the technical expertise and experience to accomplish the result. We believe that the concept of engineering is monozukuri. Through the process of monozukuri, engineered natural science based on mathematics and physics has been developed. Medicine is the field of study which has been developed for maintaining daily healthy life with diagnosis, treatment, examination, and protection. Biomedical engineering is the interdisciplinary study of engineering and medicine, and should be developed based on monozukuri. In this particular research, we have developed a physical molecular delivery method for cancer gene therapy using nano/microbubbles and ultrasound. First, the behavior of cavitation bubbles and subsequent shock wave phenomena involved in the mechanism of molecular delivery were analyzed, combining theory and computer simulation. In a second step, the methodology was optimized in vitro and in vivo. Finally, the therapeutic potential of the method in pre-clinical models was evaluated using transgenes relevant to cancer gene therapy instead of reporter genes, and whole body, non-invasive imaging using single photon emission computed tomography (SPECT/CT) was used to evaluate the selectivity of gene delivery in vivo.     

The use of molecular imaging of gene expression by radiotracers in gene therapy

Introduction: Progress with gene-based therapies has been hampered by difficulties in monitoring the biodistribution and kinetics of vector-mediated gene expression. Recent developments in non-invasive imaging have allowed researchers and clinicians to assess the location, magnitude and persistence of gene expression in animals and humans. Such advances should eventually lead to improvement in the efficacy and safety of current clinical protocols for future treatments.

Areas covered: The molecular imaging techniques for monitoring gene therapy in the living subject, with a specific highlight on the key reporter gene approaches that have been developed and validated in preclinical models using the latest imaging modalities. The applications of molecular imaging to biotherapy, with a particular emphasis on monitoring of gene and vector biodistribution and on image-guided radiotherapy.

Expert opinion: Among the reporter gene/probe combinations that have been described so far, one stands out, in our view, as the most versatile and easy to implement: the Na/I symporter. This strategy, exploiting more than 50 years of experience in the treatment of differentiated thyroid carcinomas, has been validated in different types of experimental cancers and with different types of oncolytic viruses and is likely to become a key tool in the implementation of human gene therapy.     

The use of molecular imaging of gene expression by radiotracers in gene therapy

INTRODUCTION: Progress with gene-based therapies has been hampered by difficulties in monitoring the biodistribution and kinetics of vector-mediated gene expression. Recent developments in non-invasive imaging have allowed researchers and clinicians to assess the location, magnitude and persistence of gene expression in animals and humans. Such advances should eventually lead to improvement in the efficacy and safety of current clinical protocols for future treatments. AREAS COVERED: The molecular imaging techniques for monitoring gene therapy in the living subject, with a specific highlight on the key reporter gene approaches that have been developed and validated in preclinical models using the latest imaging modalities. The applications of molecular imaging to biotherapy, with a particular emphasis on monitoring of gene and vector biodistribution and on image-guided radiotherapy. EXPERT OPINION: Among the reporter gene/probe combinations that have been described so far, one stands out, in our view, as the most versatile and easy to implement: the Na/I symporter. This strategy, exploiting more than 50 years of experience in the treatment of differentiated thyroid carcinomas, has been validated in different types of experimental cancers and with different types of oncolytic viruses and is likely to become a key tool in the implementation of human gene therapy.     

Targeting molecular mechanisms for cancer therapy

Cancer development is considered by the dysregulated proliferation of transformed cells. In recent years, dramatic and remarkable insight into the molecular mechanisms of this phenomenon have come from basic cancer research. Detailed knowledge of the molecular mechanisms and pathophysiology of cancer allows therapeutic agents to be designed that specifically target aberrant cellular processes. There are currently a number of targeted treatment strategies with less toxicity being evaluated. In the future, it is likely that this mechanistic and targeted approach will have a significant impact on clinical oncology and the diagnostic evaluation of tumors.     

Allosterically controllable maxizymes for molecular gene therapy

Ribozymes are small and versatile nucleic acids that can cleave RNAs at specific sites. These molecules have great potential to be used as effective gene therapeutic agents. However, conventional ribozymes have, in some cases, failed to exhibit precise cleavage specificity because they require cleavable sequences in the target mRNA. Recently, we demonstrated that an allosterically controllable novel ribozyme, designated the maxizyme, is a powerful tool for disruption of an abnormal chimeric RNA target (BCR-ABL (b2a2) mRNA) in cells and in mice. Furthermore, more than five custom-designed maxizymes have demonstrated these allosteric functions in vitro and in vivo. Thus, maxizyme technology is not limited to a specific case but may have broad general applicability in molecular biology and in molecular gene therapy.     

A novel parasite-derived suicide gene for cancer gene therapy with specificity for lung cancer cells

The enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) expressed by the parasite Trypanosoma brucei (Tb) can convert allopurinol, a purine analogue, to corresponding nucleotides with greater efficiency than its human homologue. We have developed a retroviral system that expresses the parasitic enzyme and tested its capacity to activate the prodrug allopurinol to a cytotoxic metabolite. Cytotoxicity assays demonstrated that five non-small cell lung carcinoma cell lines transduced with the construct were sensitized to the prodrug by 2.1- to 7.6-fold compared with control values. This selectivity was not observed in seven other cell lines also expressing the construct, such as breast carcinoma. Assays indicated that enhanced cytotoxicity to allopurinol correlated with induction of apoptosis in lung cancer cells. The selectivity of this suicide gene was not explained either by the TbHGPRT expression or by the allopurinol accumulation. Our study shows that this novel system may represent a therapeutic tool for gene prodrug targeting of lung cancer, considering the fact that allopurinol is well tolerated in humans.     

Parvovirus vectors for cancer gene therapy

Parvoviruses comprise a group of single-stranded DNA viruses with greater potential for gene therapy applications. Unique characteristics of paroviruses, such as non-pathogenicity, antioncogenicity and methods of efficient recombinant vector production, have drawn more attention towards utilising parvovirus-based vectors in cancer gene therapy. Although > 30 different parvoviruses have been identified so far, recombinant vectors derived from adeno-associated virus (AAV), minute virus of mice (MVM), LuIII and parvovirus H1 have been successfully tested in many preclinical models of human diseases, including cancer. The present article will focus on the potential of non-replicating and autonomously replicating parvoviral vectors in cancer gene therapy, including strategies that target tumour cells directly or indirectly.     

Tissue-specific promoters for cancer gene therapy

Adenoviral cancer gene therapy approaches have resulted in promising recent results. Following only a decade of intense development, some of the crucial obstacles are now being overcome. Insufficient transduction has been the main limitation of earlier approaches. A new approach for increasing transduction of tumour cells is utilisation of replication-competent oncolytic agents, such as conditionally replicating adenoviruses (CRADs). The anti-tumour effect is caused by replication of the virus per se and, thus, replication must be restricted to tumour cells to protect normal tissues from damage. Tissue-specific promoters (TSPs) represent a powerful tool for decreasing the toxicity of cancer gene therapy to normal tissues and have previously been utilised for specific mutation compensation or delivery of prodrug-converting enzymes. However, TSPs can also be used for controlling crucial viral replication regulators and consequent restriction of replication to tumour cells. Initial clinical trials have demonstrated the safety and suggested efficacy for TSP-controlled CRADs as a novel approach for cancer gene therapy.     

宫颈癌分子靶向治疗的研究新进展

宫颈癌作为女性最常见的恶性肿瘤,发病率在全球女性肿瘤中占第二位,并且具有年轻化的趋势.传统手术和放化疗在治疗宫颈癌方面非常局限,随着分子生物学和免疫学技术的发展,宫颈癌治疗逐渐向微观方向发展,其中备受关注的是宫颈癌分子靶向治疗,现已进入临床研究阶段.     

Tissue-specific promoters for cancer gene therapy

Adenoviral cancer gene therapy approaches have resulted in promising recent results. Following only a decade of intense development, some of the crucial obstacles are now being overcome. Insufficient transduction has been the main limitation of earlier approaches. A new approach for increasing transduction of tumour cells is utilisation of replication-competent oncolytic agents, such as conditionally replicating adenoviruses (CRADs). The anti-tumour effect is caused by replication of the virus per se and, thus, replication must be restricted to tumour cells to protect normal tissues from damage. Tissue-specific promoters (TSPs) represent a powerful tool for decreasing the toxicity of cancer gene therapy to normal tissues and have previously been utilised for specific mutation compensation or delivery of prodrug-converting enzymes. However, TSPs can also be used for controlling crucial viral replication regulators and consequent restriction of replication to tumour cells. Initial clinical trials have demonstrated the safety and suggested efficacy for TSP-controlled CRADs as a novel approach for cancer gene therapy.     

Development of gene therapy for pancreatic cancer

In order to develop the new therapeutic intervention for pancreatic cancer, we have examined the effect of gene therapy for this miserable pancreatic disease. The transfection of UPRT, a 5-FU converting enzyme, gene resulted in the significant change in sensitivity of pancreatic cancer cells against 5-FU. Anti-angiogenesis gene therapy has been also demonstrated to be a promising strategy for pancreatic cancer. It has been revealed that replication-competent adenoviruses are not only the strong weapon themselves but also useful carriers of genes possessing anti-tumor activities as virus vectors specific to tumors without normal p53 function nor intact Rb pathway. Whether these experimental results are universally true require the clinical trials in future.     

Satellite DNA-based artificial chromosomes for use in gene therapy

Satellite DNA-based artificial chromosomes (SATACs) can be made by induced de novo chromosome formation in cells of different mammalian species. These artificially generated accessory chromosomes are composed of predictable DNA sequences and they contain defined genetic information. Prototype human SATACs have been successfully constructed in different cell types from 'neutral' endogenous DNA sequences from the short arm of the human chromosome 15. SATACs have already passed a number of hurdles crucial to their further development as gene therapy vectors, including: large-scale purification; transfer of purified artificial chromosomes into different cells and embryos; generation of transgenic animals and germline transmission with purified SATACs; and the tissue-specific expression of a therapeutic gene from an artificial chromosome in the milk of transgenic animals.     

胰腺癌的基因治疗进展

近年来,胰腺癌的基因治疗作为一种新的治疗手段备受关注,其很多研究已进入临床阶段.胰腺癌基因治疗的研究主要包括：基因信号传导抑制、基因治疗等.本文就近期胰腺癌的基因治疗研究成果与存在的问题作一综述.     

A model for optimizing adenoviral delivery in human cancer gene therapy trials

Optimization of adenoviral delivery to the target volume is required for adenovirus-mediated cancer gene therapy to reach its maximal potential. The purpose of these studies was to develop a model of gene expression to improve adenovirus-mediated cancer gene therapy in the clinic. We measured the distribution of gene expression after a single deposit of a replication-competent adenovirus carrying the human sodium iodide symporter (hNIS) reporter gene was delivered to naive canine prostate and to human tumor xenografts. We generated hypothetical treatment plans for two prospective prostate cancer patients, using standard brachytherapy algorithms. In both models, the gene expression distribution from a single adenoviral deposit could be accurately described by a Gaussian function. In the naive canine prostate, a 0.1-ml deposit of 3 x 10(11) viral particles (VP) resulted in a gene expression volume of 1.14 +/- 0.70 cm(3), indicating that a minimum of 40 adenoviral deposits would be required to cover a 40-cm(3) prostate with therapeutic gene expression. On a viral particle basis, the gene expression volume obtained in human tumor xenografts (7 x 10(-12) cm(3)/VP) was twice that (3.5 x 10(-12) cm(3)/VP) measured in the naive canine prostate. Hypothetical treatment plans for two prostates indicated that 26 and 57 0.1-ml adenoviral deposits would be required to cover, respectively, 24- and 49-cm(3) prostates with gene expression. Although our studies focused on prostate, we believe the methodology to model gene expression presented here has much broader application to optimize treatment plans in other solid tumor sites; this assertion should be confirmed experimentally.     

Breakthroughs in cancer gene therapy

OBJECTIVES: To give oncology nurses an overview on the vectors and selected approaches used in the current clinical trials involving gene transfer to cancer patients. DATA SOURCES: Peer-reviewed scientific papers, review articles, and book chapters. CONCLUSION: Significant progress has been made in the field of cancer gene therapy. Different phases of clinical protocols derived from new generations of vectors and novel approaches are being tested for use in the treatment of patients with cancer. IMPLICATIONS FOR NURSING PRACTICE: Oncology nurses need to be familiar with current advances in the field of cancer gene therapy to expand their role as health care professional, patient educator, and advocate for the treatment of patients with cancer.     

A lentiviral vector expressing a fusogenic glycoprotein for cancer gene therapy

The gibbon ape leukaemia virus envelope fusogenic membrane glycoprotein (GALV FMG) is a highly potent cytotoxic gene with great potential for use in cancer gene therapy. Here, we show that production of a VSV-G pseudotyped lentiviral vector expressing GALV FMG reconciles the requirements of viral production with the cytotoxic effects of GALV in human cells and has high titres on both dividing and quiescent tumour cells. Direct intratumoral injection of these stocks eradicated progressively growing human tumour xenografts. The potent bystander effect of the FMG transgene is a major contributor to the success of this approach but immunological activation may also be a factor. To our knowledge, this is the first demonstration in vivo of the potential both of FMG and lentiviral vectors for cancer gene therapy and highlights the importance of exploring different vector systems to complement the biological properties of the therapeutic transgene.     

Novel angiogenesis inhibitors for molecular target therapy of cancer

Angiogenesis, neovascularization from pre-existing vasculature, is essential to allow growth of primary solid tumors and to enable metastasis. Recent biological studies in both tumor and endothelial cells have begun to present a wide variety of molecular targets for developing angiogenesis inhibitors. Therefore, angiogenesis inhibitors including anti-angiogenic agents as well as anti-vascular targeting agents have become promising drugs in cancer chemotherapy. However current unsolved problems in anti-angiogenic therapy are the lack of surrogate markers for therapeutic efficacy, as well as of establishment of effective combinations with other therapeutic approaches including conventional anticancer therapy, radiotherapy, and immunotherapy. This article focuses on the promising drugs with anti-angiogenic activity and their molecular targets under clinical trials, as well as the significance of clinical evaluation for anti-angiogenic therapies.