Liposomal 2-Methoxyestradiol Nanoparticles for Treatment of Uterine Leiomyoma in a Patient-Derived Xenograft Mouse Model

The Role of Nanomedicine in Benign Gynecologic Disorders

Nanomedicine has revolutionized drug delivery in the last two decades. Nanoparticles appear to be a promising drug delivery platform in the treatment of various gynecological disorders including uterine leiomyoma, endometriosis, polycystic ovarian syndrome (PCOS), and menopause. Nanoparticles are tiny (mean size < 1000 nm), biodegradable, biocompatible, non-toxic, safe, and relatively inexpensive materials commonly used in imaging and the drug delivery of various therapeutics, such as chemotherapeutics, small molecule inhibitors, immune mediators, protein peptides and non-coding RNA. We performed a literature review of published studies to examine the role of nanoparticles in treating uterine leiomyoma, endometriosis, PCOS, and menopause. In uterine leiomyoma, nanoparticles containing 2-methoxyestradiole and simvastatin, promising uterine fibroid treatments, have been effective in significantly inhibiting tumor growth compared to controls in in vivo mouse models with patient-derived leiomyoma xenografts. Nanoparticles have also shown efficacy in delivering magnetic hyperthermia to ablate endometriotic tissue. Moreover, nanoparticles can be used to deliver hormones and have shown efficacy as a mechanism for transdermal hormone replacement therapy in individuals with menopause. In this review, we aim to summarize research findings and report the efficacy of nanoparticles and nanotherapeutics in the treatment of various benign gynecologic conditions.

2-Methoxyestradiol and Hydrogen Peroxide as Promising Biomarkers in Parkinson's Disease

Estrogens function in numerous physiological processes including controlling brain cell growth and differentiation. 2-Methoxestradiol (2-ME2), a 17β-estradiol (E2) metabolite, is known for its anticancer effects as observed both in vivo and in vitro. 2-ME2 affects all actively dividing cells, including neurons. The study aimed to determine whether 2-ME2 is a potentially cancer-protective or rather neurodegenerative agent in a specific tissue culture model as well as a clinical setup. In this study, 2-ME2 activity was determined in a Parkinson's disease (PD) in vitro model based on the neuroblastoma SH-SY5Y cell line. The obtained results suggest that 2-ME2 generates nitro-oxidative stress and controls heat shock proteins (HSP), resulting in DNA strand breakage and apoptosis. On the one hand, it may affect intensely dividing cells preventing cancer development; however, on the other hand, this kind of activity within the central nervous system may promote neurodegenerative diseases like PD. Thus, the translational value of 2-ME2's neurotoxic activity in a PD in vitro model was also investigated. LC-MS/MS technique was used to evaluate estrogens and their derivatives, namely, hydroxy and methoxyestrogens, in PD patients' blood, whereas the stopped-flow method was used to assess hydrogen peroxide (H2O2) levels. Methoxyestrogens and H2O2 levels were increased in patients' blood as compared to control subjects, but hydoxyestrogens were simultaneously decreased. From the above, we suggest that the determination of plasma levels of methoxyestrogens and H2O2 may be a novel PD biomarker. The presented research is the subject of the pending patent application "The use of hydrogen peroxide and 17β-estradiol and its metabolites as biomarkers in the diagnosis of neurodegenerative diseases," no. P.441360.

Oestrogen receptor-independent actions of oestrogen in cancer

Oestrogen, the primary female sex hormone, plays a significant role in tumourigenesis. The major pathway for oestrogen is via binding to its receptor [oestrogen receptor (ERα or β)], followed by nuclear translocation and transcriptional regulation of target genes. Almost 70% of breast tumours are ER + , and endocrine therapies with selective ER modulators (tamoxifen) have been successfully applied. As many as 25% of tamoxifen-treated patients experience disease relapse within 5 years upon completion of chemotherapy. In such cases, the ER-independent oestrogen actions provide a plausible explanation for the resistance, as well as expands the existing horizon of available drug targets. ER-independent oestrogen signalling occurs via one of the following pathways: signalling through membrane receptors, oxidative catabolism giving rise to genotoxic metabolites, effects on mitochondria and redox balance, and induction of inflammatory cytokines. The current review focuses on the non-classical oestrogen signalling, its role in cancer, and its clinical significance.

PEGylated Polymeric Nanoparticles Loaded with 2-Methoxyestradiol for the Treatment of Uterine Leiomyoma in a Patient-Derived Xenograft Mouse Model

Leiomyomas, the most common benign neoplasms of the female reproductive tract, currently have limited medical treatment options. Drugs targeting estrogen/progesterone signaling are used, but side effects and limited efficacy in many cases are major limitation of their clinical use. Previous studies from our laboratory and others demonstrated that 2-methoxyestradiol (2-ME) is promising treatment for uterine fibroids. However, its poor bioavailability and rapid degradation hinder its development for clinical use. The objective of this study is to evaluate the in vivo effect of biodegradable and biocompatible 2-ME-loaded polymeric nanoparticles in a patient-derived leiomyoma xenograft mouse model. PEGylated poly(lactide-co-glycolide) (PEG-PLGA) nanoparticles loaded with 2-ME were prepared by nanoprecipitation. Female 6-week age immunodeficient NOG (NOD/Shi-scid/IL-2Rγnull) mice were used. Estrogen-progesterone pellets were implanted subcutaneously. Five days later, patient-derived human fibroid tumors were xenografted bilaterally subcutaneously. Engrafted mice were treated with 2-ME-loaded or blank (control) PEGylated nanoparticles. Nanoparticles were injected intraperitoneally and after 28 days of treatment, tumor volume was measured by caliper following hair removal, and tumors were removed and weighed. Up to 99.1% encapsulation efficiency was achieved, and the in vitro release profile showed minimal burst release, thus confirming the high encapsulation efficiency. In vivo administration of the 2-ME-loaded nanoparticles led to 51% growth inhibition of xenografted tumors compared to controls (P < 0.01). Thus, 2-ME-loaded nanoparticles may represent a novel approach for the treatment of uterine fibroids.

Oxidative Stress Inducers in Cancer Therapy: Preclinical and Clinical Evidence

Reactive oxygen species (ROS) are metabolic byproducts that regulate various cellular processes. However, at high levels, ROS induce oxidative stress, which in turn can trigger cell death. Cancer cells alter the redox homeostasis to facilitate protumorigenic processes; however, this leaves them vulnerable to further increases in ROS levels. This paradox has been exploited as a cancer therapeutic strategy with the use of pro-oxidative drugs. Many chemotherapeutic drugs presently in clinical use, such as cisplatin and doxorubicin, induce ROS as one of their mechanisms of action. Further, various drugs, including phytochemicals and small molecules, that are presently being investigated in preclinical and clinical studies attribute their anticancer activity to ROS induction. Consistently, this review aims to highlight selected pro-oxidative drugs whose anticancer potential has been characterized with specific focus on phytochemicals, mechanisms of ROS induction, and anticancer effects downstream of ROS induction.

Pre-clinical models to study abnormal uterine bleeding (AUB)

Abnormal Uterine Bleeding (AUB) is a common debilitating condition that significantly reduces quality of life of women across the reproductive age span. AUB creates significant morbidity, medical, social, and economic problems for women, their families, workplace, and health services. Despite the profoundly negative effects of AUB on public health, advancement in understanding the pathophysiology of AUB and the discovery of novel effective therapies is slow due to lack of reliable pre-clinical models. This review discusses currently available laboratory-based pre-clinical scientific models and how they are used to study AUB. Human and animal in vitro, ex vivo, and in vivo models will be described along with advantages and limitations of each method.

Preparation of 2-Methoxyestradiol Self-emulsified Drug Delivery System and the Effect on Combination Therapy with Doxorubicin Against MCF-7/ADM Cells

Due to the poor solubility and bioavailability of 2-methoxyestradiol (2-ME), 2-ME emulsified drug delivery system (2-ME-SEDDS) was designed and characterized. After dilution with 5% glucose, 2-ME-SEDDS formed fine emulsions with mean diameter of 171 ± 14 nm and zeta potential of - 7.4 ± 0.6 mV. The cytotoxicity of 2-ME-SEDDS against MCF-7 and MCF-7/ADM cells was considerable to that of free 2-ME, and the half maximal inhibitory concentration ran up to 195 µg/mL on MCF-7/ADM cells. In order to gain a satisfactory inhibition effect on MCF-7/ADM cells, 2-ME-SEDDS combined with doxorubicin was used. It is worth noting that the combination of 2-ME-SEDDS and doxorubicin displayed a superior synergistic effect with a combined index of 0.62. And the cellular uptake of doxorubicin by MCF-7/ADM cells in the combination group was significantly higher than that of doxorubicin treatment group. The study preliminarily suggested that 2-ME-SEDDS could increase the cellular uptake of doxorubicin by MCF-7/ADM cells and the synergistic effect may be attributed to the increased cellular uptake of doxorubicin under the influence of 2-ME-SEDDS. In conclusion, SEDDS was an alternative and promising formulation for 2-ME. The combination therapy with synergistic effect by the combination of 2-ME-SEDDS and doxorubicin seems to be a promising strategy to potentiate anti-tumor efficiency against MCF-7/ADM, even other multidrug resistance tumors.

Hypoxia induces proliferation via NOX4-Mediated oxidative stress and TGF-β3 signaling in uterine leiomyoma cells

Uterine leiomyomas, the most common tumors of the female reproductive system, are known to have a hypoxic microenvironment. However, the role of such environment in leiomyoma pathobiology remains unknown. The objective was to determine the effects of hypoxia on leiomyoma cells, and the mechanisms. We found that hypoxia induces proliferation and inhibits apoptosis in human leiomyoma cells. This pro-proliferative effect was accompanied by an increase in reactive oxygen species (ROS) generation and the expression of NADPH oxidase 4 (NOX4). The specific NOX4 inhibitor GLX351322 abrogated this hypoxia-induced ROS generation, cellular proliferation, and apoptosis inhibition. To further investigate the mechanism of NOX4-mediated proliferation, we treated leiomyoma cells grown in normoxia with media from leiomyoma cells cultured under hypoxia. This resulted in increased ROS generation and NOX4 expression, suggesting the hypoxia-induced effects are mediated by an autocrine mechanism. We worked to identify the nature of this autocrine factor. We found that the expression of TGF-β3 and its downstream signaling target pSmad3, are increased in hypoxic leiomyoma cells. To examine the hypothesis that TGF-β3 is, at least, a part of this autocrine mechanism, we treated hypoxic leiomyoma cells with the HIF-1α inhibitor KC7F2 which we discovered to ameliorate the hypoxia-induced TGF-β3 expression. Furthermore, pharmacologic inhibition with the TGF-β/Smad inhibitor SB431542 reduced hypoxia-induced NOX4 expression and ROS generation and attenuated cell proliferation. Thus, we have identified a novel mechanism by which hypoxia induces proliferation in leiomyoma cells. This finding adds to our understanding of leiomyoma pathobiology and can help in identifying new therapeutic targets.

Development and In Vitro Evaluation of 2-Methoxyestradiol Loaded Polymeric Micelles for Enhancing Anticancer Activities in Prostate Cancer

The present study aimed to formulate and optimize 2ME-loaded PMs (2ME-PMs) for enhancing the anticancer activity of 2ME in prostate cancer (PC). The 2ME-PMs were formulated using PEG-PLGA (PL), Tween 80 (TW80), and alpha-lipoic acid (ALA). The optimization was carried out using a Box-Behnken design with the PL, TW80, and ALA as the independent variables and particle size (PS) as the response. The formulation was optimized for the lowest possible PS, and the software suggested optimum formula with 100.282 mg, 2%, and 40 mg for PL, TW80, and ALA, respectively. The optimized PMs had spherical morphology with PS of 65.36 ± 2.2 nm, polydispersity index (PDI) of 0.273 ± 0.03, and entrapment efficiency of 65.23 ± 3.5%. The in vitro drug release was 76.3 ± 3.2% after 24 h. The cell line studies using PC-3 cells showed IC50 values of 18.75 and 54.41 µmol for 2ME-PM and 2ME, respectively. The estimation of tumor biomarkers was also carried out. The tumor biomarkers caspase-9 (17.38 ± 1.42 ng/mL), tumor protein P53 (p53) (1050.0 ± 40.9 pg/mL), nitric oxide (NO) (0.693 ± 0.03 pg/mL), interleukin-1β (IL-1β) (25.84 ± 2.23 pg/mL), nuclear factor kappa B (NF-kB) (0.719 ± 0.07 pg/mL), interleukin-6 (IL-6) (2.53 ± 0.16 folds), and cyclooxygenase-2 (COX-2) (3.04 ± 0.5 folds) were determined for 2ME-PMs and the results showed that these values changed significantly compared to those of 2ME. Overall, the results showed that the formulation of 2ME to 2ME-PMs enhances the anticancer effect. The exploration of the combined advantages of PEG, PLGA, ALA, and PMs in cancer therapy and the delivery of 2ME is the major importance of this research work. PEG reduces the elimination of 2ME, PLGA enhances 2ME loading, ALA has an inherent apoptotic effect, and PMs can efficiently target tumor cells.

Regulation of Mitochondrial Dynamics in Parkinson's Disease-Is 2-Methoxyestradiol a Missing Piece?

Mitochondria, as "power house of the cell", are crucial players in cell pathophysiology. Beyond adenosine triphosphate (ATP) production, they take part in a generation of reactive oxygen species (ROS), regulation of cell signaling and cell death. Dysregulation of mitochondrial dynamics may lead to cancers and neurodegeneration; however, the fusion/fission cycle allows mitochondria to adapt to metabolic needs of the cell. There are multiple data suggesting that disturbed mitochondrial homeostasis can lead to Parkinson's disease (PD) development. 2-methoxyestradiol (2-ME), metabolite of 17β-estradiol (E2) and potential anticancer agent, was demonstrated to inhibit cell growth of hippocampal HT22 cells by means of nitric oxide synthase (NOS) production and oxidative stress at both pharmacologically and also physiologically relevant concentrations. Moreover, 2-ME was suggested to inhibit mitochondrial biogenesis and to be a dynamic regulator. This review is a comprehensive discussion, from both scientific and clinical point of view, about the influence of 2-ME on mitochondria and its plausible role as a modulator of neuron survival.