Towards fibroid gene therapy: adenovirus-mediated delivery of herpes simplex virus 1 thymidine kinase gene/ganciclovir shrinks uterine leiomyoma in the Eker rat model

Genetic Mechanisms Driving Uterine Leiomyoma Pathobiology, Epidemiology, and Treatment

Uterine leiomyomas (ULs) are the most common benign tumor of the uterus. They can be associated with symptoms including abnormal uterine bleeding, pelvic pain, urinary frequency, and pregnancy complications. Despite the high prevalence of UL, its underlying pathophysiology mechanisms have historically been poorly understood. Several mechanisms of pathogenesis have been suggested, implicating various genes, growth factors, cytokines, chemokines, and microRNA aberrations. The purpose of this study is to summarize the current research on the relationship of genetics with UL. Specifically, we performed a literature review of published studies to identify how genetic aberrations drive pathophysiology, epidemiology, and therapeutic approaches of UL. With regards to pathophysiology, research has identified MED12 mutations, HMGA2 overexpression, fumarate hydratase deficiency, and cytogenetic abnormalities as contributors to the development of UL. Additionally, epigenetic modifications, such as histone acetylation and DNA methylation, have been identified as contributing to UL tumorigenesis. Specifically, UL stem cells have been found to contain a unique DNA methylation pattern compared to more differentiated UL cells, suggesting that DNA methylation has a role in tumorigenesis. On a population level, genome-wide association studies (GWASs) and epidemiologic analyses have identified 23 genetic loci associated with younger age at menarche and UL growth. Additionally, various GWASs have investigated genetic loci as potential drivers of racial disparities in UL incidence. For example, decreased expression of Cytohesin 4 in African Americans has been associated with increased UL risk. Recent studies have investigated various therapeutic options, including ten-eleven translocation proteins mediating DNA methylation, adenovirus vectors for drug delivery, and "suicide gene therapy" to induce apoptosis. Overall, improved understanding of the genetic and epigenetic drivers of UL on an individual and population level can propel the discovery of novel therapeutic options.

Serum-Resistant Ternary DNA Polyplexes for Suicide Gene Therapy of Uterine Leiomyoma

Uterine leiomyoma (UL) is a prevalent benign tumor in women that frequently gives rise to a multitude of reproductive complications. The use of suicide gene therapy has been proposed as a highly promising method for treating UL. To achieve successful gene therapy, it is essential to develop carriers that can efficiently transport nucleic acids into targeted cells and tissues. The instability of polyplexes in blood and other biological fluids is a crucial factor to consider when using non-viral carriers. In this study, we present serum-resistant and cRGD-modified DNA complexes for targeted delivery genes to UL cells. Ternary polyplexes were formed by incorporating cystine-cross-linked polyglutamic acid modified with histidine residues. We employed two techniques in the production of cross-linked polyanionic coating: matrix polymerization and oxidative polycondensation. In this study, we investigated the physicochemical properties of ternary DNA complexes, including the size and zeta-potential of the nanoparticles. Additionally, we evaluated cellular uptake, toxicity levels, transfection efficiency and specificity in vitro. The study involved introducing the HSV-TK gene into primary UL cells as a form of suicide gene therapy modeling. We have effectively employed ternary peptide-based complexes for gene delivery into the UL organtypic model. By implementing in situ suicide gene therapy, the increase in apoptosis genes expression was detected, providing conclusive evidence of apoptosis occurring in the transfected UL tissues. The results of the study strongly suggest that the developed ternary polyplexes show potential as a valuable tool in the implementation of suicide gene therapy for UL.

The Role of Gene Therapy in Premature Ovarian Insufficiency Management

Premature ovarian insufficiency (POI) is a highly prevalent disorder, characterized by the development of menopause before the age of 40. Most cases are idiopathic; however, in some women the cause of this condition (e.g.; anticancer treatment, genetic disorders, and enzymatic defects) could be identified. Although hormone-replacement therapy, the principal therapeutic approach for POI, helps alleviate the related symptoms, this does not effectively solve the issue of fertility. Assisted reproductive techniques also lack efficacy in these women. Thus, an effective approach to manage patients with POI is highly warranted. Several mechanisms associated with POI have been identified, including the lack of function of the follicle-stimulating hormone (FSH) receptor, alterations in apoptosis control, mutations in Sal-like 4 genes, and thymulin or basonuclin-1 deficiency. The above mentioned may be good targets for gene therapy in order to correct defects leading to POI. The goal of this review is to summarize current experiences on POI studies that employed gene therapy, and to discuss possible future directions in this field.

Magnetic nanoparticles as a new approach to improve the efficacy of gene therapy against differentiated human uterine fibroid cells and tumor-initiating stem cells

OBJECTIVE

To study whether efficient transduction and subsequent elimination of fibroid tumor-initiating stem cells during debulking of tumor cells will aid in completely eradicating the tumor as well as decreasing the likelihood of recurrence.

DESIGN

Case control study.

SETTING

Research laboratory.

PATIENT(S)

None.

INTERVENTION(S)

Magnetic nanoparticles (MNPs) complexed to adenovirus (Ad-GFP) or (Ad-LacZ) used to transfect differentiated human fibroid cells in vitro.

MAIN OUTCOME MEASURE(S)

Rate of transduction and tumor growth inhibition.

RESULT(S)

We have developed a localized nonsurgical adenovirus-based alternative for the treatment of uterine fibroids that combines viral-based gene delivery with nanotechnology for more efficient targeting. Magnetic nanoparticles complexed to adenovirus, in the presence of an external magnetic field, accelerate adenovirus transduction. We observed a statistically significant increase in transduction efficiency among differentiated human fibroid cells at two different multiplicities of infection (MOI), 1 and 10, respectively, with MNPs as compared with adenovirus alone. Human fibroid stem cells transfected with Ad-LacZ expressed β-galactosidaze at a MOI of 1, 10, and 50 at 19%, 62%, and 90%, respectively, which were statistically significantly enhanced with MNPs.

CONCLUSION(S)

When applied with adenovirus herpes simplex thymidine kinase, magnetofection statistically significantly suppressed proliferation and induced apoptosis in both cell types. Through the use of magnetofection, we will prove that a lower viral dose will effectively increase the overall safety profile of suicide gene therapy against fibroid tumors.

Early Life Adverse Environmental Exposures Increase the Risk of Uterine Fibroid Development: Role of Epigenetic Regulation

Uterine Fibroids [UF(s), AKA: leiomyoma] are the most important benign neoplastic threat to women's health. They are the most common cause of hysterectomy imposing untold personal consequences and 100s of billions of healthcare dollars, worldwide. Currently, there is no long term effective FDA-approved medical treatment available, and surgery is the mainstay. The etiology of UFs is not fully understood. In this regard, we and others have recently reported that somatic mutations in the gene encoding the transcriptional mediator subunit Med12 are found to occur at a high frequency (∼85%) in UFs. UFs likely originate when a Med12 mutation occurs in a myometrial stem cell converting it into a tumor-forming stem cell leading to a clonal fibroid lesion. Although the molecular attributes underlying the mechanistic formation of UFs is largely unknown, a growing body of literature implicates unfavorable early life environmental exposures as potentially important contributors. Early life exposure to EDCs during sensitive windows of development can reprogram normal physiological responses and alter disease susceptibility later in life. Neonatal exposure to the EDCs such as diethylstilbestrol (DES) and genistein during reproductive tract development has been shown to increase the incidence, multiplicity and overall size of UFs in the Eker rat model, concomitantly reprogramming estrogen-responsive gene expression. Importantly, EDC exposure represses enhancer of zeste 2 (EZH2) and reduces levels of histone 3 lysine 27 trimethylation (H3K27me3) repressive mark through Estrogen receptor/Phosphatidylinositide 3-kinases/Protein kinase B non-genomic signaling in the developing uterus. Considering the fact that distinct Mediator Complex Subunit 12 (Med12) mutations are detected in different fibroid lesions in the same uterus, the emergence of each Med12 mutation is likely an independent event in an altered myometrial stem cell. It is therefore possible that a chronic reduction in DNA repair capacity eventually causes the emergence of mutations such as Med12 in myometrial stem cells converting them into fibroid tumor-forming stem cells, and thereby leads to the development of UFs. Advancing our understanding of the mechanistic role epigenetic regulation of stem cells plays in mediating risk and tumorigenesis will help in pointing the way toward the development of novel therapeutic options.

Targeted Adenoviral Vector Demonstrates Enhanced Efficacy for In Vivo Gene Therapy of Uterine Leiomyoma

BACKGROUND

Gene therapy is a potentially effective non-surgical approach for the treatment of uterine leiomyoma. We demonstrated that targeted adenovirus vector, Ad-SSTR-RGD-TK/GCV, was highly effective in selectively inducing apoptosis and inhibiting proliferation of human leiomyoma cells in vitro while sparing normal myometrial cells.

STUDY DESIGN

An in-vivo study, to compare efficacy and safety of modified adenovirus vector Ad-SSTR-RGD-TK/GCV versus untargeted vector for treatment of leiomyoma.

MATERIALS AND METHODS

Female nude mice were implanted with rat leiomyoma cells subcutaneously. Then mice were randomized into three groups. Group 1 received Ad-LacZ (marker gene), Group 2 received untargeted Ad-TK, and Group 3 received the targeted Ad-SSTR-RGD-TK. Tumors were measured weekly for 4 weeks. Then mice were sacrificed and tissue samples were collected. Evaluation of markers of apoptosis, proliferation, extracellular matrix, and angiogenesis was performed using Western Blot & Immunohistochemistry. Statistical analysis was done using ANOVA. Dissemination of adenovirus was assessed by PCR.

RESULTS

In comparison with the untargeted vector, the targeted adenoviral vector significantly shrank leiomyoma size (P < 0.05), reduced expression of proliferation marker (PCNA) (P < 0.05), induced expression of apoptotic protein, c-PARP-1, (P < 0.05) and inhibited expression of extracellular matrix-related genes (TGF beta 3) and angiogenesis-related genes (VEGF & IGF-1) (P < 0.01). There were no detectable adenovirus in tested tissues other than leiomyoma lesions with both targeted and untargeted adenovirus.

CONCLUSION

Targeted adenovirus, effectively reduces tumor size in leiomyoma without dissemination to other organs. Further evaluation of this localized targeted strategy for gene therapy is needed in appropriate preclinical humanoid animal models in preparation for a future pilot human trial.

Enhancing Adenoviral-Mediated Gene Transfer and Expression to Endometrial Cells

OBJECTIVE

Our aim was to screen a panel of modified adenoviral gene transfer vectors to identify those which can sustain high gene expression in human endometrial cells.

METHODS

Normal endometrial stromal cell cultures were established from endometrial lining of hysterectomy specimens performed for benign gynecologic indications. Human endometrial stromal cells were transfected by modified adenoviruses expressing luciferase reporter gene. Luciferase activity mediated by each virus was expressed as a percentage of adenovirus serotype 5 (Ad5-CMV-luc) activity. The 2-tailed Student t test was used to compare data.

RESULTS

At a multiplicity of infection (MOI) of 10 pfu/cell, of the transductionally modified adenoviruses, adenovirus-RGD (Ad-RGD-luc) mediated highest level of endometrial cell transduction with transgene expression around 4 times higher when compared to Ad5 (P < .001). Of the transcriptionally targeted adenoviruses, adenovirus under secretory leukocyte protease inhibitor promoter (Ad-SLPI-luc) and adenovirus under heparanase promoter (Ad-heparanase-luc)-mediated luciferase activation were 5.8- and 4.3-folds higher than Ad5-CMV-luc, respectively (P = .02 and .03, respectively). At MOI of 50 pfu/cell, Ad-RGD-luc and AD-SLPI-luc mediated significantly higher gene transfer efficiency compared to Ad5-CMV-luc (P values < .001, for each virus). Ad-heparanase-luc achieved higher gene activity, but difference was not significant (P = .1). Ad-SLPI-luc, at low viral dose (10 pfu/ cell), mediated gene expression effect comparable to Ad5-CMV-luc at a high dose (50 pfu/cell), with no significant difference.

CONCLUSIONS

We conclude that when compared to the wild-type adenovirus, Ad-RGD-luc, Ad-SLPI-luc, and Ad-heparanase-luc mediate higher reporter gene activity in endometrial cells and can work as effective gene transfer vectors in gene therapy applications to the endometrium.

Uterine fibroids: clinical manifestations and contemporary management

Uterine fibroids (leiomyomata) are extremely common lesions that are associated with detrimental effects including infertility and abnormal uterine bleeding. Fibroids cause molecular changes at the level of endometrium. Abnormal regulation of growth factors and cytokines in fibroid cells may contribute to negative endometrial effects. Understanding of fibroid biology has greatly increased over the last decade. Although the current armamentarium of Food and Drug Administration-approved medical therapies is limited, there are medications approved for use in heavy menstrual bleeding that can be used for the medical management of fibroids. Emergence of the role of growth factors in pathophysiology of fibroids has led researchers to develop novel therapeutics. Despite advances in medical therapies, surgical management remains a mainstay of fibroid treatment. Destruction of fibroids by interventional radiological procedures provides other effective treatments. Further experimental studies and clinical trials are required to determine which therapies will provide the greatest benefits to patients with fibroids.

The role of angiogenic factors in fibroid pathogenesis: potential implications for future therapy

BACKGROUND

It is well established that tumors are dependent on angiogenesis for their growth and survival. Although uterine fibroids are known to be benign tumors with reduced vascularization, recent work demonstrates that the vasculature of fibroids is grossly and microscopically abnormal. Accumulating evidence suggests that angiogenic growth factor dysregulation may be implicated in these vascular and other features of fibroid pathophysiology.

METHODS

Literature searches were performed in PubMed and Google Scholar for articles with content related to angiogenic growth factors and myometrium/leiomyoma. The findings are hereby reviewed and discussed.

RESULTS

Multiple growth factors involved in angiogenesis are differentially expressed in leiomyoma compared with myometrium. These include epidermal growth factor (EGF), heparin-binding-EGF, vascular endothelial growth factor, basic fibroblast growth factor, platelet-derived growth factor, transforming growth factor-β and adrenomedullin. An important paradox is that although leiomyoma tissues are hypoxic, leiomyoma feature down-regulation of key molecular regulators of the hypoxia response. Furthermore, the hypoxic milieu of leiomyoma may contribute to fibroid development and growth. Notably, common treatments for fibroids such as GnRH agonists and uterine artery embolization (UAE) are shown to work at least partly via anti-angiogenic mechanisms.

CONCLUSIONS

Angiogenic growth factors play an important role in mechanisms of fibroid pathophysiology, including abnormal vasculature and fibroid growth and survival. Moreover, the fibroid's abnormal vasculature together with its aberrant hypoxic and angiogenic response may make it especially vulnerable to disruption of its vascular supply, a feature which could be exploited for treatment. Further experimental studies are required in order to gain a better understanding of the growth factors that are involved in normal and pathological myometrial angiogenesis, and to assess the potential of anti-angiogenic treatment strategies for uterine fibroids.

Targeting adenoviral vectors for enhanced gene therapy of uterine leiomyomas

STUDY QUESTION

Is targeted adenovirus vector, Ad-SSTR-RGD-TK (Adenovirus -human somatostatin receptor subtype 2- arginine, glycine and aspartate-thymidine kinase), given in combination with ganciclovir (GCV) against immortalized human leiomyoma cells (HuLM) a potential therapy for uterine fibroids?

SUMMARY ANSWER

Ad-SSTR-RGD-TK/GCV, a targeted adenovirus, effectively reduces cell growth in HuLM cells and to a significantly greater extent than in human uterine smooth muscle cells (UtSM).

WHAT IS KNOWN ALREADY

Uterine fibroids (leiomyomas), a major cause of morbidity and the most common indication for hysterectomy in premenopausal women, are well-defined tumors, making gene therapy a suitable and potentially effective non-surgical approach for treatment. Transduction of uterine fibroid cells with adenoviral vectors such as Ad-TK/GCV (herpes simplex virus thymidine kinase gene) decreases cell proliferation.

STUDY DESIGN, SIZE, DURATION

An in vitro cell culture method was set up to compare and test the efficacy of a modified adenovirus vector with different multiplicities of infection in two human immortalized cell lines for 5 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Immortalized human leiomyoma cells and human uterine smooth muscle cells were infected with different multiplicities of infection (MOI) (5-100 plaque-forming units (pfu)/cell) of a modified Ad-SSTR-RGD-TK vector and subsequently treated with GCV. For comparison, HuLM and UtSM cells were transfected with Ad-TK/GCV and Ad-LacZ/GCV. Cell proliferation was measured using the CyQuant assay in both cell types. Additionally, western blotting was used to assess the expression of proteins responsible for regulating proliferation and apoptosis in the cells.

MAIN RESULTS AND THE ROLE OF CHANCE

Transduction of HuLM cells with Ad-SSTR-RGD-TK/GCV at 5, 10, 50 and 100 pfu/cell decreased cell proliferation by 28, 33, 45, and 84%, respectively (P < 0.05) compared with untransfected cells, whereas cell proliferation in UtSM cells transfected with the same four MOIs of Ad-SSTR-RGD-TK/GCV compared with that of untransfected cells was decreased only by 8, 23, 25, and 28%, respectively (P < 0.01). Western blot analysis showed that, in comparison with the untargeted vector Ad-TK, Ad-SSTR-RGD-TK/GCV more effectively reduced expression of proteins that regulate the cell cycle (Cyclin D1) and proliferation (PCNA, Proliferating Cell Nuclear Antigen), and it induced expression of the apoptotic protein BAX, in HuLM cells.

LIMITATIONS, REASONS FOR CAUTION

Results from this study need to be replicated in an appropriate animal model before testing this adenoviral vector in a human trial.

WIDER IMPLICATIONS OF THE FINDINGS

Effective targeting of gene therapy to leiomyoma cells enhances its potential as a non-invasive treatment of uterine fibroids.

Towards non-surgical therapy for uterine fibroids: catechol-O-methyl transferase inhibitor shrinks uterine fibroid lesions in the Eker rat model

BACKGROUND

Uterine leiomyomas (fibroids) are the most common pelvic tumors in women. We assessed the potential therapeutic utility of Ro 41-0960, a synthetic catechol-O-methyl transferase inhibitor (COMTI), in the Eker rat.

METHODS

We randomized uterine fibroid-bearing Eker rats for treatment with Ro 41-0960 (150 mg/kg/12 h) versus vehicle for 2 and 4 weeks. The fibroids were measured by caliper and subjected to histological evaluation. Urinary levels of 2-hydroxy estrogen (E(2)), 16-hydroxy E2 and DPD (osteoporosis marker) and serum liver enzymes were evaluated. Expressions of Cyclin D1, proliferating cell nuclear antigen (PCNA), Poly [ADP-ribose] polymerase1 (PARP1), tumor suppressor gene (P53) and transforming growth factor (TGFβ3) were assessed in fibroids using immunohistochemical analysis or RT-PCR. Apoptosis was confirmed using terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling (TUNEL).

RESULTS

Ro 41-0960-treated rats exhibited fibroid volumes of 86 ± 7% and 105 ± 12% of initial burden, at 2 and 4 weeks post-treatment, respectively, significantly lower than control group (240 ± 15% and 300 ± 18%; P< 0.01). Ro 41-0960 increased the urinary 2-hydroxy E2/16-hydroxy E(2) ratio, level of p53 mRNA and TUNEL positivity (P< 0.05) and decreased PARP1, PCNA and cyclin D1 proteins and TGFβ3 mRNA (P< 0.05). Ro 41-0960 did not change normal tissue histology, liver functions or urinary DPD level.

CONCLUSIONS

Ro 41-0960 (COMTI) arrested growth/shrunk uterine fibroids in Eker rats. This result may be related to modulation of estrogen-dependent genes involved in apoptosis, proliferation and extracellular matrix deposition via accumulation of 2-hydroxy estrogen. The efficacy and safety of Ro 41-0960 in rats suggest its candidacy for treatment of uterine fibroids.

Proceedings from theNational Institute of Child Health and Human Development conference on the Uterine Fibroid Research Update Workshop

The purpose of the National Institutes of Health conference Fibroid Research Workshop in September 2007 was to bring Eunice Kennedy Shriver National Institute of Child Health and Human Development-funded fibroid investigators together to discuss basic science and clinical research advances on uterine leiomyomata. General topics included advances in epidemiology, etiology, therapeutic approaches, and clinical trial challenges; suggestions for advancement of basic understanding, clinical intervention, clinical trials, and future directions were highlighted.

Toward gene therapy of premature ovarian failure: intraovarian injection of adenovirus expressing human FSH receptor restores folliculogenesis in FSHR(-/-) FORKO mice

A homozygous missense mutation, C566T, in the follicle stimulation hormone receptor (FSHR) gene has been linked to premature ovarian failure. The disease leads to infertility in a normal karyotype female with an elevated follicle stimulating hormone (FSH) and decreased serum estrogen level. Female mice carrying mutated FSHR gene, called follitropin receptor knockout (FORKO), display similar phenotype and are sterile because of a folliculogenesis block at a primary stage. We investigated the effects of bilateral intra-ovarian injection of an adenovirus expressing a normal copy of human FSHR on the reproductive system of 6-10 weeks female FORKO mice. Ad-LacZ was injected directly into each ovary of the control group. Animals were sacrificed at 2, 4, 8 and 12 weeks post-injection and tissues collected for evaluation. Treated mice showed estrogenic changes in daily vaginal smear whereas control animals remained fixated in the diestrus stage. Histological evaluation showed on average 26 +/- 4 follicles/ovary in treated group with 8 +/- 2 follicles at the antral stage compared with only 5 +/- 2 with zero follicles at antral stage in Ad-LacZ control mice. There was no significant change in serum level of progesterone, however, estrogen level increased 2-3-fold (P < 0.02) and FSH decreased by up to 50% (P < 0.04) in treated animals. FSHR mRNA was detected in the ovaries of the treated group. In conclusion, intra-ovarian injection of an adenovirus expressing human FSHR gene is able to restore FSH responsiveness and reinitiate ovarian folliculogenesis as well as resume estrogen production in female FORKO mice. Ad-LacZ injections indicate the absence of systemic viral dissemination or germ line transmission of adenovirus DNA to offspring.

Distribution of CPP-Protein Complexes in Freshly Resected Human Tissue Material

Interest in cell-penetrating peptides (CPPs) as delivery agents has fuelled a large number of studies conducted on cultured cells and in mice. However, only a few studies have been devoted to the behaviour of CPPs in human tissues. Therefore, we performed ex vivo tissue-dipping experiments where we studied the distribution of CPP-protein complexes in samples of freshly harvested human tissue material. We used the carcinoma or hyperplasia-containing specimens of the uterus and the cervix, obtained as surgical waste from nine hysterectomies. Our aim was to evaluate the tissue of preference (epithelial versus muscular/connective tissue, carcinoma versus adjacent histologically normal tissue) for two well-studied CPPs, the transportan and the TAT-peptide. We complexed biotinylated CPPs with avidin--galactosidase (ABG), which enabled us to apply whole-mount X-gal staining as a robust detection method. Our results demonstrate that both peptides enhanced the tissue distribution of ABG. The enhancing effect of the tested CPPs was more obvious in the normal tissue and in some specimens we detected a striking selectivity of CPP-ABG complexes for the normal tissue. This unexpected finding encourages the evaluation of CPPs as local delivery agents in non-malignant situations, for example in the intrauterine gene therapy of benign gynaecological diseases.

Gene therapy of benign gynecological diseases

Gene therapy is the introduction of genetic material into patient's cells to achieve therapeutic benefit. Advances in molecular biology techniques and better understanding of disease pathogenesis have validated the use of a variety of genes as potential molecular targets for gene therapy based approaches. Gene therapy strategies include: mutation compensation of dysregulated genes; replacement of defective tumor-suppressor genes; inactivation of oncogenes; introduction of suicide genes; immunogenic therapy and antiangiogenesis based approaches. Preclinical studies of gene therapy for various gynecological disorders have not only shown to be feasible, but also showed promising results in diseases such as uterine leiomyomas and endometriosis. In recent years, significant improvement in gene transfer technology has led to the development of targetable vectors, which have fewer side-effects without compromising their efficacy. This review provides an update on developing gene therapy approaches to treat common gynecological diseases such as uterine leiomyoma and endometriosis.