Current Gene Therapy - Volume 18, Issue 4, 2018

Breast cancer continues to be a leading cause of mortality among women. While at an early stage, localized breast cancer is easily treated; however, advanced stages of disease continue to carry a high mortality rate. The discrepancy in treatment success highlights that current treatments are insufficient to treat advanced-stage breast cancer. As new and improved treatments have been sought, one therapeutic approach has gained considerable attention. Oncolytic viruses are uniquely capable of targeting cancer cells through intrinsic or engineered means. They come in many forms, mainly from four major virus groups as defined by the Baltimore classification system. These vectors can target and kill cancer cells, and even stimulate immunotherapeutic effects in patients. This review discusses not only individual oncolytic viruses pursued in the context of breast cancer treatment but also the emergence of combination therapies with current or new therapies, which has become a particularly promising strategy for treatment of breast cancer. Overall, oncolytic virotherapy is a promising strategy for increased treatment efficacy for advanced breast cancer and consequently provides a unique platform for personalized treatments in patients.

Parkinson's Disease (PD) is a frustrating condition characterized by motor and nonmotor deficits majorly caused by the loss of dopaminergic cells in the Substantia Nigra pars compacta (SNc) and destruction of the nigrostriatal pathway. Despite the very respectable advances in cutting-edge approaches for the treatment of PD, there exist numerous challenges that have incapacitated the definitive treatment of this disease. This review emphasized the development of various non-pharmaceutical therapeutic approaches and mainly highlighted the cutting-edge treatments for PD including gene- and stem cell-based therapies, targeted delivery of neurotrophic factors, and brain stimulation techniques such as Transcranial Magnetic Stimulation (TMS), transcranial Direct Current Stimulation (tDCS), and Deep Brain Stimulation (DBS). The review covered various gene therapy strategies including Adeno-Associated Virus-Glutamic Acid Decarboxylase (AAV-GAD), AAV–Aromatic L-Amino Acid Decarboxylase (AAV-AADC), Lenti-AADC/Tyrosine Hydroxylase/Guanosine Triphosphate- Cyclohydrolase I (Lenti-AADC/TH/GTP-CH1), AAV–Neurturin (AAV-NRTN), α-Synuclein silencing, and PRKN gene delivery. Also, the advantages, disadvantages, and the results of trials of these methods were discussed. Finally, reasons for the failure of PD treatment were described, with the hopes separated from hypes.

Erectile Dysfunction (ED) is a common health condition occuring in roughly 50% of aging males (40-70 years old). Recent attention has related gene therapy to ED, and now there is an interest to further implement gene therapy concepts to ED treatment. This review is an attempt to analyze key challenges and emphasize primary areas, including mostly preclinical and a few clinical trials, cellular target(s), and different viral vectors/nanoparticles for gene delivery in ED. While overexpression of target genes can be silenced by RNA interference (RNAi), down-regulation of these mechanisms has been implicated in ED. Although many patients with ED demonstrate efficacy with phosphodiesterase type 5 inhibitors, this therapy is insufficient in approximately 30-40% of patients. Although several preclinical studies for ED treatment provided promising results, gene therapy has not shown success in clinical practice, due in part to technical limitations of gene therapy to address ED pathogenesis. Developments in small RNA, such as small interfering RNA (siRNA) may lead to significant benefit in the management of ED. Also, siRNA delivery into the corpus cavernosum seems a challenging issue and awaits further development. Several safety concerns of gene therapy, gene acquisition, preparation, and delivery are necessary to continue investigation before any widespread application is used in ED treatment.

Background: Insulin-like Growth Factor1 (IGF1) is a powerful neuroprotective molecule. We have previously shown that short-term hypothalamic IGF1 gene therapy restores tuberoinfundibular dopaminergic neuron function in aging female rats. Objective: Our aim was to implement long-term IGF-I gene therapy in pituitary prolactinomas in senile female rats. Methods: Here, we assessed the long-term effect of IGF1 gene therapy in the hypothalamus of young (4 mo.) and aging (24 mo.) female rats carrying spontaneous pituitary prolactinomas. We constructed and injected a Helper-Dependent (HD) adenovector expressing the gene for rat IGF1 or the reporter red fluorescent protein DsRed. Ninety-one days post vector injection, all rats were sacrificed and their brains and pituitaries fixed. Serum prolactin (PRL), Estrogen (E2) and progesterone (P4), as well as hypothalamic IGF1 content, were measured by RIA. Anterior pituitaries were immunostained with an anti-rat PRL antibody and submitted to morphometric analysis. Results: DsRed expression in the Mediobasal Hypothalamus (MBH) was strong after the treatment in the DsRed group while IGF1 content in the MBH was higher in the IGF1 group. The IGF1 treatment affected neither pituitary weight nor PRL, E2 or P4 serum levels in the young rats. In the old rats, IGF1 gene therapy reduced gland weight as compared with intact counterparts and tended to reduce PRL levels as compared with intact counterparts. The treatment significantly rescued the phenotype of the lactotropic cell population in the senile adenomas. Conclusion: We conclude that long-term hypothalamic IGF1 gene therapy is effective to rescue spontaneous prolactinomas in aging female rats.

Duchenne muscular dystrophy is a disorder with variable expression caused by framedisrupting mutations in the dystrophin gene. It is characterized by progressive muscle weakness and dilated cardiomyopathy. In-frame dystrophin mutations cause a clinically moderate disorder named Becker muscular dystrophy. Our aim was to study the clinical and genetic characteristics of a family with inherited cardiomyopathy and Becker muscular dystrophy. The index case was diagnosed with psychomotor retardation at 5 years of age. Asymmetric left ventricular hypertrophy and a long QT interval were evidenced at the age of 12. Mild muscular weakness was developed subsequently. Three genetic variants were identified in the index case: p.Arg891Alafs*160 in the MYBPC3 gene, p.Thr263Met in the KCNJ5 gene, and p.Ser2437_Ile2554delinsPhe in the DMD gene. The latter was expected to generate an in-frame deletion of exons 51 and 52 of the dystrophin gene. A family study revealed that the father and 3 uncles were carriers of the MYBPC3 mutation. The mother and a maternal grandfather were carriers of the other 2 variants. The 80-year-old grandfather, who had the dystrophin mutation, showed no sign of cardiomyopathy or muscular weakness. The deletion of exons 51 and 52 in the DMD gene, which has been proposed as one of the therapeutic strategies for Duchenne, is consistent with a normal life expectancy and the absence of myopathic symptoms in hemizygous males.