Estrogens and androgens inhibit association of RANKL with the pre-osteoblast membrane through post-translational mechanisms

Associations of Hormonal and Metabolic Parameters with Bone Mineralization in Young Adult Females

Osteoporosis is characterized by impaired bone mineralization and microarchitecture. An important protective factor is a high peak bone mass (PBM), attained in the second and third decade of life. The aim of the study was to evaluate the effect of hormonal and metabolic parameters on bone mineralization in young adult female patients. A total of 111 participants qualified for the study. Bone mineral density of the lumbar spine (L1-L4) and whole skeleton was measured using dual-energy X-ray absorptiometry (DXA). Hormonal parameters were determined: the concentrations of androstendione, dihydroepiandrosterone sulphate, testosterone, sex hormone binding protein, 17-OH-progesterone, folliculotropic hormone, estradiol, thyrotropic hormone, free thyroxine and cortisol. Metabolic parameters were also examined. The study showed a statistically significant correlation between bone mineral density and estradiol concentration and a negative relationship between cortisol concentration and the bone mineral density (BMD) Z-score of the lumbar spine. Sclerostin measurements taken during this study were not related to bone mineral density. It has been shown that the concentration of the hormones tested, even within the reference range, may affect bone mineralization. We suggest observing the follow-up of the menstrual cycles, as well as analyzing the results of test patients in an annual examination system. However, each clinical case should be considered individually. The sclerostin test is currently not useful in the clinical evaluation of bone mineralization in young adult women.

Associations of Bone Mineral Density with RANKL and Osteoprotegerin in Arab Postmenopausal Women: A Cross-Sectional Study

Background and objective: There is limited information as to the association of several key bone markers with bone mineral density (BMD) in understudied ethnic groups. This study investigated the relationship between circulating levels of osteoprotegerin (OPG) and receptor activator of nuclear factor kappa-Β ligand (RANKL) with BMD in Arab postmenopausal women. Materials and methods: In this cross-sectional study, a total of 617 Saudi postmenopausal women from the Osteoporosis Registry of the Chair for Biomarkers of Chronic Diseases were included. Anthropometric data, BMD, and biochemical data were retrieved from the registry. Participants were stratified into three groups based on T-score; n = 169 with osteoporosis, n = 282 with osteopenia, and n = 166 normal. Analysis of bone markers including RANKL, OPG, osteocalcin, and N-terminal telopeptide (NTx) was completed using commercially available bioassays. Results: The results suggested that OPG was significantly and positively correlated with age in the osteoporosis group (r = 0.29, p < 0.05), while it was inversely correlated with BMD femoral neck left (r = −0.56, p < 0.001) and BMD femoral neck right (r = −0.37, p < 0.05) in the same group. Moreover, RANKL showed a significant inverse correlation with NTx in the osteopenia group (r = −0.37, p < 0.05). Furthermore, the RANKL/OPG ratio had a positive and significant correlation with BMI (r = 0.34, p < 0.05), BMD femoral neck left (r = 0.36, p < 0.05) and BMD femoral neck right (r = 0.35, p < 0.05) in the osteopenia group. By contrast, it showed a significant inverse correlation with waist to hip ratio in the osteoporosis group (r = −0.38, p < 0.05). Multiple regression analysis showed that OPG contributes to BMD variations in the osteopenia group (p = 0.03). Conclusions: In conclusion, changes in circulating levels of RANKL and OPG might be a protective mechanism contrary to the increased bone loss in postmenopausal women.

Mechanisms and Future of Non-Small Cell Lung Cancer Metastasis

Lung cancer, renowned for its fast progression and metastatic potency, is rising to become a leading cause of death globally. It has been long observed that lung cancer is particularly ept in spawning distant metastasis at its early stages, and it can readily colonize virtually any human organ. In recent years, cancer research has shed light on why lung cancer is endowed with its exceptional ability to metastasize. In this review, we will take a comprehensive look at the current research on lung cancer metastasis, including molecular pathways, anatomical features and genetic traits that make lung cancer intrinsically metastatic, as we go from lung cancer’s general metastatic potential to the particular metastasis mechanisms in multiple organs. We highly concerned about the advanced discovery and development of lung cancer metastasis, indicating the importance of lung cancer specific gene mutations, heterogeneity or biomarker discovery, and discussing potential opportunities and challenges. We will also introduce some current treatments that targets certain metastatic strategies of non-small cell lung cancer (NSCLC). Advances made in these regards could be critical to our current knowledge base of lung cancer metastasis.

Hyaluronic Acid Modified Risedronate and Teriparatide Co-loaded Nanocarriers for Improved Osteogenic Differentiation of Osteoblasts for the Treatment of Osteoporosis

BACKGROUND

Owing to its multifactorial intricate pathogenesis, combined therapeutic regimen is considered appropriate for the treatment of osteoporosis. However, a multi-drug regimen is also associated with adverse effects due to the non-specific distribution of drugs. Therefore, the present study aims for efficient codelivery of risedronate (RDN) (a potent bone anti-resorptive drug) and teriparatide (TPD) (anabolic agent) as hyaluronic acid (HA)-modified chitosan nanoparticles (NPs).

METHODS

RDN/TPD NPs were synthesized using the high- pressure homogenization - solvent evaporation technique. The fabricated NPs were then characterized and optimized for suitable physicochemical characteristics. The optimized NPs were then evaluated for bone remodeling potential via assessment of time-mannered modulation in proliferation, differentiation, and mineralization of osteoblasts.

RESULTS

Results showed that HA-RDN/TPD NPs exhibited excellent physicochemical characteristics (nanoscopic size, stable zeta potential, high entrapment efficiency, and smooth spherical shape) and remained stable upon storage in the refrigerator. Assessment of various aspects of the cell growth cycle (i.e., proliferation, differentiation, and mineralization) evidenced promising bone regeneration efficacy of HA-RDN/TPD NPs.

CONCLUSION

This new strategy of employing simultaneous delivery of anti-resorptive and bone-forming agents would open new horizons for scientists, researchers, and healthcare providers as an efficient pharmacotherapy for the treatment of osteoporosis.

Association Between Urinary Triclosan With Bone Mass Density and Osteoporosis in US Adult Women, 2005‒2010

CONTEXT

Laboratory studies have demonstrated that triclosan (TCS) can cause significant interstitial collagen accumulation and an increase in trabecular bone. However, little is known about the relationship between TCS exposure and human bone health.

METHODS

We used 2005 to 2010 National Health and Nutrition Examination Survey data to examine the association between urinary TCS concentration and bone mineral density (BMD) and osteoporosis in US adult women aged ≥20 years. After inclusion and exclusion, 1848 women were analyzed.

RESULTS

After adjustment for other covariates, we observed significant associations between tertile 3 of TCS concentration and lower BMD in regions of the total femur (β = -0.016; 95% CI = -0.032, -0.000), intertrochanteric region (β = -0.022; 95% CI = -0.042, -0.002), and lumbar spine (β = -0.014; 95% CI = -0.029, 0.001), respectively, relative to tertile 1. Compared with women at tertile 1, those at tertile 3 were more likely to have increased prevalence of osteoporosis in the intertrochanteric region (OR = 2.464; 95% CI = 1.190, 5.105).

CONCLUSION

This epidemiological study investigated the association between urinary TCS concentration and BMD and osteoporosis in US adult women. We found urinary TCS concentration was negatively associated with BMD and was positively associated with the prevalence of osteoporosis. The evidence was stronger in postmenopausal women than in premenopausal women. Future prospective studies are needed to validate these findings.

Influences of Sex and Estrogen in Arterial and Valvular Calcification

Vascular and cardiac valvular calcification was once considered to be a degenerative and end stage product in aging cardiovascular tissues. Over the past two decades, however, a critical mass of data has shown that cardiovascular calcification can be an active and highly regulated process. While the incidence of calcification in the coronary arteries and cardiac valves is higher in men than in age-matched women, a high index of calcification associates with increased morbidity, and mortality in both sexes. Despite the ubiquitous portending of poor outcomes in both sexes, our understanding of mechanisms of calcification under the dramatically different biological contexts of sex and hormonal milieu remains rudimentary. Understanding how the critical context of these variables inform our understanding of mechanisms of calcification-as well as innovative strategies to target it therapeutically-is essential to advancing the fields of both cardiovascular disease and fundamental mechanisms of aging. This review will explore potential sex and sex-steroid differences in the basic biological pathways associated with vascular and cardiac valvular tissue calcification, and potential strategies of pharmacological therapy to reduce or slow these processes.

Estrogens and selective estrogen receptor modulators differentially antagonize Runx2 in ST2 mesenchymal progenitor cells

Estrogens attenuate bone turnover by inhibiting both osteoclasts and osteoblasts, in part through antagonizing Runx2. Apparently conflicting, stimulatory effects in osteoblast lineage cells, however, sway the balance between bone resorption and bone formation in favor of the latter. Consistent with this dualism, 17ß-estradiol (E2) both stimulates and inhibits Runx2 in a locus-specific manner, and here we provide evidence for such locus-specific regulation of Runx2 by E2 in vivo. We also demonstrate dual, negative and positive, regulation of Runx2-driven alkaline phosphatase (ALP) activity by increasing E2 concentrations in ST2 osteoblast progenitor cells. We further compared the effects of E2 to those of the Selective Estrogen Receptor Modulators (SERMs) raloxifene (ral) and lasofoxifene (las) and the phytoestrogen puerarin. We found that E2 at the physiological concentrations of 0.1-1 nM, as well as ral and las, but not puerarin, antagonize Runx2-driven ALP activity. At ≥10 nM, E2 and puerarin, but not ral or las, stimulate ALP relative to the activity measured at 0.1-1 nM. Contrasting the difference between E2 and SERMs in ST2 cells, they all shared a similar dose-response profile when inhibiting pre-osteoclast proliferation. That ral and las poorly mimic the locus- and concentration-dependent effects of E2 in mesenchymal progenitor cells may help explain their limited clinical efficacy.

Icariin stimulates osteogenic differentiation and suppresses adipogenic differentiation of rBMSCs via estrogen receptor signaling

Icariin (ICA) is a major active ingredient in Herba epimedii, which is commonly used as a Chinese herbal medicine for the treatment of osteoporosis. Previous studies have revealed that ICA exerted a protective effect against bone loss and increased bone regeneration; however, the association between ICA and estrogen receptor (ER) signaling remains unclear. The aim of the present study was to determine the effect of ICA on rat bone marrow stromal cells (rBMSCs). Cell Counting Kit‑8 assays were conducted to measure proliferation, alkaline phosphatase (ALP) activity was evaluated to assess osteoblast differentiation, and reverse transcription‑quantitative polymerase chain reaction as well as western blotting were performed to detect the expression of cellular and molecular markers of osteogenic or adipogenic differentiation. The results demonstrated that treatment of rBMSCs with 10‑6 M ICA stimulated rBMSC proliferation and ALP activity. Furthermore, ICA treatment increased the expression of the osteogenic markers runt‑related transcription factor 2, collagen type 1 and bone morphogenetic Protein 2; however, it also decreased the expression of the adipogenic differentiation markers peroxisome proliferator‑activated receptor gamma and CCAAT/enhancer‑binding protein α. Treatment of rBMSCs with ICI182780, an ER antagonist, blocked the effects of ICA. Taken together, these findings indicated that ICA may stimulate osteoblast differentiation and inhibit adipogenic differentiation via the activation of the ER signaling pathway. Therefore, ICA has the potential to serve as a therapeutic alternative for the prevention and treatment of osteoporosis.

Communication between genomic and non-genomic signaling events coordinate steroid hormone actions

Steroid hormones are lipophilic molecules produced in one cell that can travel great distances within the body to elicit biological effects in another cell. In the canonical pathway, steroid hormone binding to a nuclear receptor (NR), often in the cytoplasm, causes the receptor to undergo a conformational change and translocate to the nucleus, where it interacts with specific sequences of DNA to regulate transcription. In addition to the classical genomic mechanism of action, alternate mechanisms of steroid activity have emerged that involve rapid, non-genomic signaling. The distinction between these two major mechanisms of action lies in the subcellular location of the initiating steroid hormone action. Importantly, the mechanisms of action are not exclusive, in that each can affect the activity of the other. Here, we describe the different types of genomic and non-genomic steroid hormone signaling mechanisms and how they can influence one another to ultimately regulate biology. Further, we discuss the approaches being used to study the non-genomic signaling events and address important caveats to be considered when designing new experiments. Thus, this minireview can serve as an introduction to the diverse signaling mechanisms of steroid hormones and offers initial, experimental guidance to those entering the field.

miR-539 inhibits human colorectal cancer progression by targeting RUNX2

Emerging evidence has shown that microRNAs (miRNAs) such as miR-539 play critical roles in carcinogenesis and progression in many types of cancer, including human colorectal cancer (CRC). However, the roles and underlying mechanism of miR-539 in CRC have not been well identified. The aims of this study were, therefore, to investigate the regulatory role and potential mechanism of miR-539 in human CRC. Here, we show that miR-539 expression is downregulated in CRC tissues and cell lines. The expression level of miR-539 is inversely associated with advanced clinical stage and lymph node metastasis. In vitro studies reveal that overexpression of miR-539 inhibits CRC cell proliferation and colony formation as well as migration and invasion; in vivo results demonstrate that overexpression of miR-539 dramatically reduces CRC xenograft tumor growth. Moreover, runt-related transcription factor 2 (RUNX2), a known oncogene, was identified as a target transcript of miR-539 in CRC by bioinformatic analysis, luciferase reporter assay, qPCR, and western blotting. RUNX2 expression levels were upregulated and inversely correlated with miR-539 expression in CRC tissues. Importantly, overexpression of RUNX2 without the 3'-untranslated region that is targeted by miR-539 partially reversed the inhibitory effect of miR-539 on CRC cell proliferation, migration, and invasion. Collectively, these findings demonstrate that miR-539 functions as a tumor suppressor in CRC, at least in part, by targeting RUNX2, supporting the targeting of the novel miR-539 as a potentially effective therapeutic approach for treatment of CRC.

MiR-23a targets RUNX2 and suppresses ginsenoside Rg1-induced angiogenesis in endothelial cells

Rg1 is a predominant protopanaxatriol-type of ginsenoside found in Panax ginseng, and it has been shown to have anti-cancer effects in multiple types of cancer cells. However, Rg1 also induces the expression of proangiogenic factors, such as vascular endothelial growth factor (VEGF-A), in endothelial cells. Unfortunately, angiogenesis positively correlates with cancer development. In this study, we identified RUNX2 as a regulator of ginsenoside Rg1-induced angiogenesis for the first time. We found that RUNX2 was directly targeted and regulated by miR-23a. Additionally, miR-23a was shown to inhibit angiogenesis in both human umbilical vein endothelial cells (HUVECs) and in zebrafish. Furthermore, a decrease in RUNX2 expression resulted in translational repression of VEGF-A in HUVECs. Taken together, this study identified a MiR-23a/RUNX2/VEGF-A pathway in angiogenesis and shed light on the molecular mechanism of Rg1-induced angiogenesis. Thus, RUNX2 might be a potential therapeutic target in Rg1-mediated angiogenesis in cancer.