Stereochemistry Enhances Potency, Efficacy, and Durability of Malat1 Antisense Oligonucleotides In Vitro and In Vivo in Multiple Species.

Purpose: Antisense oligonucleotides have been under investigation as potential therapeutics for many diseases, including inherited retinal diseases. Chemical modifications, such as chiral phosphorothioate (PS) backbone modification, are often used to improve stability and pharmacokinetic properties of these molecules. We aimed to generate a stereopure MALAT1 (metastasis-associated lung adenocarcinoma transcript 1) antisense oligonucleotide as a tool to assess the impact stereochemistry has on potency, efficacy, and durability of oligonucleotide activity when delivered by intravitreal injection to eye. Methods: We generated a stereopure oligonucleotide (MALAT1-200) and assessed the potency, efficacy, and durability of its MALAT1 RNA-depleting activity compared with a stereorandom mixture, MALAT1-181, and other controls in in vitro assays, in vivo mouse and nonhuman primate (NHP) eyes, and ex vivo human retina cultures. Results: The activity of the stereopure oligonucleotide is superior to its stereorandom mixture counterpart with the same sequence and chemical modification pattern in in vitro assays, in vivo mouse and NHP eyes, and ex vivo human retina cultures. Findings in NHPs showed durable activity of the stereopure oligonucleotide in the retina, with nearly 95% reduction of MALAT1 RNA maintained for 4 months postinjection. Conclusions: An optimized, stereopure antisense oligonucleotide shows enhanced potency, efficacy, and durability of MALAT1 RNA depletion in the eye compared with its stereorandom counterpart in multiple preclinical models. Translational Relevance: As novel therapeutics, stereopure oligonucleotides have the potential to enable infrequent administration and low-dose regimens for patients with genetic diseases of the eye.

MicroRNA-15b regulates reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression in human uterine leiomyoma.

BACKGROUND: Human uterine leiomyoma (fibroids; LYO) are the most common benign neoplasms in reproductive-aged women. Dysregulated extracellular matrix and irregular LYO reversion-inducing cysteine-rich protein with Kazal motifs (RECK) expression are thought to be mediated by aberrant microRNA (miR) expression. The relationship of miR-15b and RECK expression in LYO has not been studied. METHODS: The expression levels of miR-15b and RECK were determined by quantitative RT-PCR, Western blot, and immunohistochemistry in cultures derived from commercial primary leiomyoma (cpLYO) and myometrial (cpMYO) cell lines and leiomyoma (pLYO) and myometrium (pMYO) tissue from surgical samples respectively. The relationship between miR-15b and RECK expression in cpLYO and pLYO (compared to their respective myometrial controls) was evaluated following transfection of cell cultures with either miR-15b mimic or inhibitor. RESULTS: Elevated levels of miR-15b were observed in cpLYO (2.82-fold; p = 0.04) and pLYO cell (1.30-fold; p = 0.0001) cultures respectively compared to corresponding MYO cell controls. Following transfection with miR-15b mimic, cpLYO cells (0.62-fold; p < 0.0001) and pLYO cells (0.68-fold; p < 0.0001) demonstrated reduced RECK protein expression. Following transfection with miR-15b inhibitor, cpLYO cells (1.20-fold; p < 0.0001) and pLYO cells (1.31-fold; p = 0.0007) demonstrated elevated RECK protein expression. RECK protein expression was reduced in pLYO tissues (0.73-fold; p < 0.0001) and pLYO (0.47-fold; p = 0.047) cells when compared to the corresponding MYO tissue controls. CONCLUSION: Our findings suggest that miR-15b negatively regulates RECK expression in LYO, and increased miR-15b and decreased RECK expression may contribute to the pathobiology of LYO. The functional significance of miR-15b and RECK expression warrants further investigation as potential therapeutic targets for the treatment of human LYO.

Inhibitors of SCF-Skp2/Cks1 E3 ligase block estrogen-induced growth stimulation and degradation of nuclear p27kip1: therapeutic potential for endometrial cancer.

In many human cancers, the tumor suppressor, p27(kip1) (p27), a cyclin-dependent kinase inhibitor critical to cell cycle arrest, undergoes perpetual ubiquitin-mediated proteasomal degradation by the E3 ligase complex SCF-Skp2/Cks1 and/or cytoplasmic mislocalization. Lack of nuclear p27 causes aberrant cell cycle progression, and cytoplasmic p27 mediates cell migration/metastasis. We previously showed that mitogenic 17-ß-estradiol (E2) induces degradation of p27 by the E3 ligase Skp1-Cullin1-F-Box- S phase kinase-associated protein2/cyclin dependent kinase regulatory subunit 1 in primary endometrial epithelial cells and endometrial carcinoma (ECA) cell lines, suggesting a pathogenic mechanism for type I ECA, an E2-induced cancer. The current studies show that treatment of endometrial carcinoma cells-1 (ECC-1) with small molecule inhibitors of Skp2/Cks1 E3 ligase activity (Skp2E3LIs) stabilizes p27 in the nucleus, decreases p27 in the cytoplasm, and prevents E2-induced proliferation and degradation of p27 in endometrial carcinoma cells-1 and primary ECA cells. Furthermore, Skp2E3LIs increase p27 half-life by 6 hours, inhibit cell proliferation (IC50, 14.3µM), block retinoblastoma protein (pRB) phosphorylation, induce G1 phase block, and are not cytotoxic. Similarly, using super resolution fluorescence localization microscopy and quantification, Skp2E3LIs increase p27 protein in the nucleus by 1.8-fold. In vivo, injection of Skp2E3LIs significantly increases nuclear p27 and reduces proliferation of endometrial epithelial cells by 42%-62% in ovariectomized E2-primed mice. Skp2E3LIs are specific inhibitors of proteolytic degradation that pharmacologically target the binding interaction between the E3 ligase, SCF-Skp2/Cks1, and p27 to stabilize nuclear p27 and prevent cell cycle progression. These targeted inhibitors have the potential to be an important therapeutic advance over general proteasome inhibitors for cancers characterized by SCF-Skp2/Cks1-mediated destruction of nuclear p27.

Prolonging the female reproductive lifespan and improving egg quality with dietary omega-3 fatty acids.

Women approaching advanced maternal age have extremely poor outcomes with both natural and assisted fertility. Moreover, the incidence of chromosomal abnormalities and birth defects increases with age. As of yet, there is no effective and practical strategy for delaying ovarian aging or improving oocyte quality. We demonstrate that the lifelong consumption of a diet rich in omega-3 fatty acids prolongs murine reproductive function into advanced maternal age, while a diet rich in omega-6 fatty acids is associated with very poor reproductive success at advanced maternal age. Furthermore, even short-term dietary treatment with a diet rich in omega-3 fatty acids initiated at the time of the normal age-related rapid decline in murine reproductive function is associated with improved oocyte quality, while short-term dietary treatment with omega-6 fatty acids results in very poor oocyte quality. Thus, omega-3 fatty acids may provide an effective and practical avenue for delaying ovarian aging and improving oocyte quality at advanced maternal age.

Effect of sunitinib on functional reproductive outcome in a rabbit model.

OBJECTIVE: To determine the effect of sunitinib (Sutent; SU11248; Pfizer), a US Food and Drug Administration-approved receptor tyrosine kinase inhibitor previously shown to reduce de novo pelvic adhesion formation, on reproductive function after surgical uterine abrasion in a rabbit model. DESIGN: Randomized placebo-controlled study. SETTING: Large animal facility within an academic hospital. ANIMAL(S): Thirty New Zealand White adult female rabbits (2.2-3.0 kg). INTERVENTION(S): Administration of 11 doses (one preoperative and 10 postoperative) of oral sunitinib (10 mg/kg/d) or placebo. MAIN OUTCOME MEASURE(S): Effect of short-term postoperative sunitinib administration on reproductive function after surgical uterine abrasion. RESULT(S): All animals were impregnated and survived until designated euthanasia. Sunitinib-treated animals had a larger average litter size (7.7 ± 1.9 vs. 5.6 ± 2.7 kits) and offspring viability (7.1 ± 2.7 vs. 3.5 ± 3.2 kits) compared with placebo-treated animals. There was no difference in gestational length or aberration in the maintenance of fertility. There were no gross abnormalities, detectable birth defects, or growth disparity in offspring from sunitinib versus placebo-treated mothers. The adhesion burden identified at euthanasia after parturition was lower in sunitinib compared with placebo-treated animals (N = 10/group). CONCLUSION(S): Sunitinib ameliorated adhesion-induced reproductive aberrations after surgical uterine abrasion and may be an efficacious strategy to reduce postoperative pelvic adhesions.

Metformin therapy in a hyperandrogenic anovulatory mutant murine model with polycystic ovarian syndrome characteristics improves oocyte maturity during superovulation.

BACKGROUND: Metformin, an oral biguanide traditionally used for the treatment of type 2 diabetes, is widely used for the management of polycystic ovary syndrome (PCOS)-related anovulation. Because of the significant prevalence of insulin resistance and glucose intolerance in PCOS patients, and their putative role in ovulatory dysfunction, the use of metformin was touted as a means to improve ovulatory function and reproductive outcomes in PCOS patients. To date, there has been inconsistent evidence to demonstrate a favorable effect of metformin on oocyte quality and competence in women with PCOS. Given the heterogeneous nature of this disorder, we hypothesized that metformin may be beneficial in mice with aberrant metabolic characteristics similar to a significant number of PCOS patients. The aim of this study was to gain insight into the in vitro and in vivo effects of metformin on oocyte development and ovulatory function. METHODS: We utilized metformin treatment in the transgenic ob/ob and db/db mutant murine models which demonstrate metabolic and reproductive characteristics similar to women with PCOS. RESULTS: Metformin did not improve in vitro oocyte maturation nor did it have an appreciable effect on in vitro granulosa cell luteinization (progesterone production) in any genotype studied. Although both mutant strains have evidence of hyperandrogenemia, anovulation, and hyperinsulinemia, only db/db mice treated with metformin had a greater number of mature oocytes and total overall oocytes compared to control. There was no observed impact on body mass, or serum glucose and androgens in any genotype. CONCLUSIONS: Our data provide evidence to suggest that metformin may optimize ovulatory performance in mice with a specific reproductive and metabolic phenotype shared by women with PCOS. The only obvious difference between the mutant murine models is that the db/db mice have elevated leptin levels raising the questions of whether their response to metformin is related to elevated leptin levels and/or if a subset of PCOS women with hyperleptinemia may be responsive to metformin therapy. Further study is needed to better define a subset of women with PCOS that may be responsive to metformin.

Cables1 protects p63 from proteasomal degradation to ensure deletion of cells after genotoxic stress.

The p63 gene product regulates epithelial morphogenesis and female germline integrity. In this study, we show that cyclin-dependent kinase 5 and Abl enzyme substrate 1 (Cables1) interacts with the trans-activating (TA) p63alpha isoform to protect it from proteasomal degradation. Using the female germline of Cables1-null mice as an in vivo model, we demonstrate further that oocytes lacking Cables1 exhibit lower basal levels of TAp63alpha and reduced accumulation of phosphorylated TAp63alpha in response to genotoxic stress. This in turn enhances the survival of these cells after ionizing radiation exposure. Thus, Cables1 modulates p63 protein stability and function during genotoxic stress.

Expression and distribution of cytokeratin 8/18 intermediate filaments in bovine antral follicles and corpus luteum: an intrinsic mechanism of resistance to apoptosis?

Apoptosis is a mechanism of cell elimination during follicular atresia and luteal regression. Recent evidence suggests sensitivity to apoptosis in some cell types is partly dependent upon cytokeratin-containing intermediate filaments. Specifically, cytokeratin 8/18 (CK8/18) filaments are thought to impart resistance to apoptosis. Here, cytokeratin filament expression within bovine ovarian follicles and corpora lutea (CL) was characterized and the potential relationship between cell-specific CK8/18 expression and apoptosis explored. Immunoprecipitation and western blot analysis confirmed CK8 associates with CK18 to form CK8/18 heterodimeric filaments within bovine ovarian cells. Immunostaining revealed populations of CK18-positive (CK18+) cells in healthy growing follicles that increased in postovulatory follicles. Atretic follicles at all stages of atresia also contained some CK18+ cells. However, no CK18+ cells were detected in primordial or primary follicles. In CL, developing CL contained a higher proportion of CK18+ cells (approximately 35%, range 30-70%) than mature CL (approximately 16%) and regressing CL (approximately 5%; P<0.05, n = 3-5 CL/stage), suggesting CK8/18 filament expression diminishes over time, as luteal cells become more susceptible to apoptosis. Dual-fluorescence labeling for CK18 and a cell death marker (TUNEL labeling) confirmed this view, demonstrating less death of CK18+ than CK18- luteal cells throughout the estrous cycle (P<0.05). The results indicate differential expression of CK8/18 filaments occurs in cells of bovine ovarian follicles and CL throughout the estrous cycle. The prevalence and cell-specific pattern of cytokeratin expression in these structures is consistent with the concept these filaments might impart resistance to apoptosis in ovarian cells as is seen in other cell types.

Upregulation of MUC4 in cervical squamous cell carcinoma: pathologic significance.

MUC4 is a transmembrane glycoprotein more highly expressed in cervical dysplasia than benign cervical epithelium. We sought to determine whether MUC4 expression differs between benign and malignant cervical tissue. Fifty-eight patients with benign, dysplastic, or malignant cervical pathology were identified retrospectively, and representative sections were stained with a mouse monoclonal anti-MUC4 antibody. Semiquantitative analysis was performed on benign, dysplastic, and malignant regions by scoring staining intensity (0: negative, 1: weak, 2: moderate, and 3: strong) and distribution (focal <10%, multifocal=10%-60%, diffuse > or =60%). In samples with benign glycogenated squamous epithelium, only the parabasal cells had MUC4 staining, and 48.5% had an intensity of 2 or 3. All samples with immature squamous metaplasia were positive through the entire epithelial thickness. Cervical intraepithelial neoplasia (CIN) 1 samples had variable staining with an intensity similar to glycogenated squamous epithelium but distribution similar to squamous metaplasia. All CIN 3 (n=21) and invasive squamous cell carcinomas (n=17) had increased MUC4 staining intensity (P<0.001 and P<0.001) and increased diffuse staining (P<0.001 and P<0.001) compared with the limited staining in glycogenated squamous epithelium. In contrast, no differences in staining were observed between benign endocervical glands, adenocarcinoma in situ, and invasive adenocarcinoma. These expression patterns suggest that MUC4 is a lineage marker in benign cervical tissue that may have aberrant expression in squamous dysplasia and carcinoma. Further studies may elucidate the role of MUC4 in the development of squamous cell cervical cancer.

Mechanisms of Cables 1 gene inactivation in human ovarian cancer development.

Cables 1, a cyclin-dependent kinase binding protein, is primarily involved in cell cycle regulation. Loss of nuclear Cables 1 expression is observed in human colon, lung and endometrial cancers. We previously reported that loss of nuclear Cables 1 expression was also observed with high frequency in a limited sample set of human ovarian carcinomas, although the mechanisms underlying loss of nuclear Cables 1 expression remained unknown. Our present objective was to examine Cables 1 expression in ovarian cancer in greater detail, and determine the predominant mechanisms of Cables 1 loss. We assessed potential genetic and epigenetic modifications of the Cables 1 locus through analyses of mutation, polymorphisms, loss of heterozygosity and DNA methylation. We observed a marked loss of nuclear Cables 1 expression in serous and endometrioid ovarian carcinomas that correlated with decreased Cables 1 mRNA levels. Although we detected no Cables 1 mutations, there was evidence of LOH at the Cables 1 locus and epigenetic modification of the Cables 1 promoter region in a subset of ovarian carcinomas and established cancer cell lines. From a functional perspective, over-expression of Cables 1 induced apoptosis, whereas, knockdown of Cables 1 negated this effect. Together these findings suggest that multiple mechanisms underlie the loss of Cables 1 expression in ovarian cancer cells, supporting the hypothesis that Cables 1 is a tumor suppressor in human ovarian cancer.

High-throughput gene discovery in the rat.

The rat is an important animal model for human diseases and is widely used in physiology. In this article we present a new strategy for gene discovery based on the production of ESTs from serially subtracted and normalized cDNA libraries, and we describe its application for the development of a comprehensive nonredundant collection of rat ESTs. Our new strategy appears to yield substantially more EST clusters per ESTs sequenced than do previous approaches that did not use serial subtraction. However, multiple rounds of library subtraction resulted in high frequencies of otherwise rare internally primed cDNAs, defining the limits of this powerful approach. To date, we have generated >200,000 3' ESTs from >100 cDNA libraries representing a wide range of tissues and developmental stages of the laboratory rat. Most importantly, we have contributed to approximately 50,000 rat UniGene clusters. We have identified, arrayed, and derived 5' ESTs from >30,000 unique rat cDNA clones. Complete information, including radiation hybrid mapping data, is also maintained locally at http://genome.uiowa.edu/clcg.html. All of the sequences described in this article have been submitted to the dbEST division of the NCBI.