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Osteoporosis (OP) is the most common skeletal disease, caused by a lack of balance between osteoclast and osteoblast activity. This results in erosion overriding the deposition of new bone matrix, consequently leading to low-quality bone and an increased risk of incurring fragility fractures. Dual energy X-ray absorptiometry is the gold standard for the diagnosis of OP, while anti-osteoporotic drugs are the gold standard for its treatment. However, due to limitations to their use, researchers have turned to epigenetics as a substantial source of molecules that could potentially be used as diagnostic, prognostic, and therapeutic biomarkers for OP. In particular, long non-coding RNAs (lncRNAs) possess special biological properties that could open new horizons in the field of personalized medicine. This mini review seeks to offer an overview of the studies carried out in the last year on the different lncRNAs that could be involved in the pathogenesis of OP and that could pave the way for the development of innovative therapeutic strategies for this disease.

n recent years the endocannabinoid system (ES) has been recognized to play an important role in the regulation of several physiological processes, including pain perception, appetite control, and motor function development. This system has recently been recognized to be present in bone and joint tissues, playing a role in the regulation of bone and joint physiology. The ES seems to play its role mainly by acting on its receptors and thanks to the demonstrated ability of bone cells to synthesize the principal endocannabinoids (i.e., anandamide and 2-arachidonoylglycerol), which can act on bone remodeling and metabolism. Cannabinoids have also been shown to be produced within synovial tissues, and recent studies have shown that cannabinoid receptor ligands are effective in the treatment of inflammatory arthritis. In recent years synthetic endocannabinoid-like compounds and phytocannabinoids, which are the principal components of Cannabis sativa, have also started to be studied as molecules that could play a role not only in bone physiology, but also in the pathogenesis of osteoporosis, the most common bone disease, and in the inflammatory processes underlying osteoarthritis. Accumulating evidence that cannabinoids and their receptors play an important role in bone metabolism and in the regulation of the immune response is now starting to show us the true future therapeutic potential of cannabinoids, and of the phytocannabinoids contained in Cannabis sativa, in the treatment of bone loss and joint diseases. Here we summarize the role of the cannabinoids and their receptors in bone metabolism, osteoporosis, and joint disease.

Osteoporosis is related to dysfunction of the crosstalk between osteoblasts and osteoclasts, the cells involved in the formation and resorption of bone, respectively. Oxidative stress and inflammation are involved in the pathogenesis of osteoporosis. Because of their antioxidant and anti-inflammatory properties, natural compounds such as polyphenols extensively present in fruit, vegetables, wine, tea, extra virgin olive oil, and berries, play an important protective role in disorders of bone metabolism, including osteoporosis. A diet rich in polyphenol-rich fruit and vegetables can reduce bone mineral density loss, decreasing the risk of fracture and preserving lifestyle quality. The aim of the present review is to highlight the principal mechanisms involved in the role played by the main dietary polyphenols in the prevention and/or treatment of osteoporosis.

Diabetes is now one of the most prevalent diseases in the world. Over the next twenty years, the number of affected individuals could reach 693 million. Diabetes is a group of chronic carbohydrate metabolism disorders responsible for increased blood glucose levels. It has several effects on the human body, and over the years can even become disabling, greatly impacting the patient’s quality of life. The most common therapy is based on daily and chronic administration of exogenous insulin, but this is associated with a series of dangerous and potentially fatal complications. Unsurprisingly therefore, over time, studies have explored various alternatives for the treatment of diabetes, not involving the use of insulin, primarily transplantation of the whole pancreas and of the islets of Langerhans. However, neither of these solutions can be applied on a large scale, mainly due to the lack of donors. In recent years, a viable alternative to insulin and to transplantation has emerged through exploration of the use of pluripotent stem cells and their properties. In this review we analyze the state of the art in this field, and the advantages and disadvantages of cell therapies used for reconstruction of the functional unit of the pancreas, the islets of Langerhans.

The pituitary gland is defined as a highly “plastic” gland, capable of adapting to the changing needs of the body over the course of a lifetime. In 1969, the first putative pituitary stem cells were isolated, defined as chromophobe cells because of their inability to secrete/incorporate hormones. Since then, studies have improved and have confirmed the presumed existence of a side population characterized by SOX2 expression in both the anterior and marginal pituitary lobes. From the numerous studies conducted to unravel the biological significance of these stem populations, it is currently believed that these cells, at least in the adult basal gland, are highly quiescent; however, their functions are still not well understood. This review reports the major advances achieved in recent years towards developing protocols for the isolation of pituitary stem cells from healthy tissue and pituitary adenomas, as well as the first studies on their use in regenerative medicine.

Bone health is ensured by coordinated work between osteoclasts and osteoblasts. When this balance is lacking, skeletal diseases, including osteoporosis (OP), arise. The latter is caused by an increase in erosion and a decrease in bone matrix deposition, resulting in low-quality bone that tends to have a higher risk of fracture. To date, despite the use of sophisticated software to diagnose OP, and the use of several drugs to mitigate the effects of this pathology, there are still limitations that drive the scientific community to search for new biomarkers. In recent years, epigenetics has attracted the attention of many researchers as a possible mechanism involved in the onset and progression of OP. In particular they have focused on circular RNAs (circRNAs), a particular class of non-coding RNAs. Precisely because of their properties, these molecules could open up new possibilities in the field of precision medicine. In conclusion, therefore, the aim of this review is to offer an overview on circRNAs, which could potentially become, in the future, useful diagnostic, prognostic and therapeutic biomarkers in OP routine clinical practice.

Wnt signaling and its bone tissue-specific inhibitor sclerostin are key regulators of bone homeostasis. The therapeutic potential of anti-sclerostin antibodies (Scl-Abs), for bone mass recovery and fragility fracture prevention in low bone mass phenotypes, has been supported by animal studies. The Scl-Ab romosozumab is currently used for osteoporosis treatment.Wnt signaling is a key regulator of skeletal development and homeostasis; germinal mutations affecting genes encoding components, inhibitors, and enhancers of the Wnt pathways were shown to be responsible for the development of rare congenital metabolic bone disorders. Sclerostin is a bone tissue-specific inhibitor of the Wnt/β-catenin pathway, secreted by osteocytes, negatively regulating osteogenic differentiation and bone formation, and promoting osteoclastogenesis and bone resorption.Here, we reviewed current knowledge on the role of sclerostin and Wnt pathways in bone metabolism and skeletal disorders, and on the state of the art of therapy with sclerostin-neutralizing antibodies in low-bone-mass diseases.Various in vivo studies on animal models of human low-bone-mass diseases showed that targeting sclerostin to recover bone mass, restore bone strength, and prevent fragility fracture was safe and effective in osteoporosis, osteogenesis imperfecta, and osteoporosis pseudoglioma. Currently, only treatment with romosozumab, a humanized monoclonal anti-sclerostin antibody, has been approved in human clinical practice for the treatment of osteoporosis, showing a valuable capability to increase BMD at various skeletal sites and reduce the occurrence of new vertebral, non-vertebral, and hip fragility fractures in treated male and female osteoporotic patients.Preclinical studies demonstrated safety and efficacy of therapy with anti-sclerostin monoclonal antibodies in the preservation/restoration of bone mass and prevention of fragility fractures in low-bone-mass clinical phenotypes, other than osteoporosis, to be validated by clinical studies for their approved translation into prevalent clinical practice.

Classically, a secosteroid hormone, vitamin D, has been implicated in calcium and phosphate homeostasis and has been associated with the pathogenesis of rickets and osteomalacia in patients with severe nutritional vitamin D deficiency. The spectrum of known vitamin D-mediated effects has been expanded in recent years. However, the mechanisms of how exactly this hormone elicits its biological function are still not fully understood. The interaction of this metabolite with the vitamin D receptor (VDR) and, subsequently, with the vitamin D-responsive element in the region of specific target genes leading to the transcription of genes whose protein products are involved in the traditional function of calcitriol (known as genomic actions). Moreover, in addition to these transcription-dependent mechanisms, it has been recognized that the biologically active form of vitamin D3, as well as its immediate precursor metabolite, calcifediol, initiate rapid, non-genomic actions through the membrane receptors that are bound as described for other steroid hormones. So far, among the best candidates responsible for mediating rapid membrane response to vitamin D metabolites are membrane-associated VDR (VDRm) and protein disulfide isomerase family A member 3 (Pdia3). The purpose of this paper is to provide an overview of the rapid, non-genomic effects of calcifediol and calcitriol, whose elucidation could improve the understanding of the vitamin D3 endocrine system. This will contribute to a better recognition of the physiological acute functions of vitamin D3, and it could lead to the identification of novel therapeutic targets able to modulate these actions.

Osteoporosis is characterized by the alteration of bone homeostasis due to an imbalance between osteoclastic bone resorption and osteoblastic bone formation. Estrogen deficiency causes bone loss and postmenopausal osteoporosis, the pathogenesis of which also involves oxidative stress, inflammatory processes, and the dysregulation of the expression of microRNAs (miRNAs) that control gene expression at post-transcriptional levels. Oxidative stress, due to an increase in reactive oxygen species (ROS), proinflammatory mediators and altered levels of miRNAs enhance osteoclastogenesis and reduce osteoblastogenesis through mechanisms involving the activation of MAPK and transcription factors. The present review summarizes the principal molecular mechanisms involved in the role of ROS and proinflammatory cytokines on osteoporosis. Moreover, it highlights the interplay among altered miRNA levels, oxidative stress, and an inflammatory state. In fact, ROS, by activating the transcriptional factors, can affect miRNA expression, and miRNAs can regulate ROS production and inflammatory processes. Therefore, the present review should help in identifying targets for the development of new therapeutic approaches to osteoporotic treatment and improve the quality of life of patients.

Several recent studies have demonstrated that the direct precursor of vitamin D3, the calcifediol [25(OH)D3], through the binding to the nuclear vitamin D receptor (VDR), is able to regulate the expression of many genes involved in several cellular processes. Considering that itself may function as a VDR ligand, although with a lower affinity, respect than the active form of vitamin D, we have assumed that 25(OH)D3 by binding the VDR could have a vitamin’s D3 activity such as activating non-genomic pathways, and in particular we selected mesenchymal stem cells derived from human adipose tissue (hADMSCs) for the in vitro assessment of the intracellular Ca2+ mobilization in response to 25(OH)D3. Our result reveals the ability of 25(OH)D3 to activate rapid, non-genomic pathways, such as an increase of intracellular Ca2+ levels, similar to what observed with the biologically active form of vitamin D3. hADMSCs loaded with Fluo-4 AM exhibited a rapid and sustained increase in intracellular Ca2+ concentration as a result of exposure to 10−5 M of 25(OH)D3. In this work, we show for the first time the in vitro ability of 25(OH)D3 to induce a rapid increase of intracellular Ca2+ levels in hADMSCs. These findings represent an important step to better understand the non-genomic effects of vitamin D3 and its role in endocrine system.

Tumors of the parathyroid glands are common endocrine diseases almost always characterized by parathyroid hormone hypersecretion that determines the clinical manifestations of primary hyperparathyroidism, such as fatigue, kidney problems, weakness, brittle bones, and other symptoms. Most parathyroid neoplasia are benign adenomas, although rare malignant forms have been described. They are heterogeneous in terms of clinical presentation and the associated signs and symptoms overlap with those of disease and aging. Furthermore, most patients with hypercalcemia are discovered during routine blood tests for other reasons. Surgical removal is considered the main therapeutic option to cure these endocrine tumors and, therefore, innovative therapeutic approaches are actively required. Recently, a growing number of studies have suggested that alterations to the epigenetic mechanisms could play a pivotal role in parathyroid tumorigenesis. Most of the attention has been focused on non-coding RNAs (ncRNAs) (i.e., miRNAs, lncRNAs, and circRNAs) whose expression profile has been found to be deregulated in parathyroid tumors. The aim of the present paper is to give an insight into the ncRNAs involved in parathyroid tumorigenesis, which could be used in the future either as innovative diagnostic biomarkers or as therapeutic targets for the treatment of this endocrine neoplasia.

Pituitary adenomas (PAs) are one of the most common lesions of intracranial neoplasms, occurring in approximately 15% of the general population. They are typically benign, although some adenomas show aggressive behavior, exhibiting rapid growth, drug resistance, and invasion of surrounding tissues. Despite ongoing improvements in diagnostic and therapeutic strategies, late first diagnosis is common, and patients with PAs are prone to relapse. Therefore, earlier diagnosis and prevention of recurrence are of importance to improve patient care. MicroRNAs (miRNAs) are short non-coding single stranded RNAs that regulate gene expression at the post-transcriptional level. An increasing number of studies indicate that a deregulation of their expression patterns is related with pituitary tumorigenesis, suggesting that these small molecules could play a critical role in contributing to tumorigenesis and the onset of these tumors by acting either as oncosuppressors or as oncogenes, depending on the biological context. This paper provides an overview of miRNAs involved in PA tumorigenesis, which might serve as novel potential diagnostic and prognostic non-invasive biomarkers, and for the future development of miRNA-based therapeutic strategies for PAs.

Osteoporosis, one of the leading causes of bone fractures, is characterized by low bone mass and structural deterioration of bone tissue, which are associated with a consequent increase in bone fragility and predisposition to fracture. Current screening tools are limited in estimating the proper assessment of fracture risk, highlighting the need to discover novel more suitable biomarkers. Genetic and environmental factors are both implicated in this disease. Increasing evidence suggests that epigenetics and, in particular, miRNAs, may represent a link between these factors and an increase of fracture risk. miRNAs are a class of small noncoding RNAs that negatively regulate gene expression. In the last decade, several miRNAs have been associated with the development of osteoporosis and bone fracture risk, opening up new possibilities in precision medicine. Recently, these molecules have been identified in several biological fluids, and the possible existence of a circulating miRNA (c-miRNA) signature years before the fracture occurrence is suggested. The aim of this review is to provide an overview of the c-miRNAs suggested as promising biomarkers for osteoporosis up until now, which could be helpful for early diagnosis and monitoring of treatment response, as well as fracture risk assessment, in osteoporotic patients.

Hypoparathyroidism is an endocrine disorder characterized by low serum calcium levels, high serum phosphorus levels, and by inappropriate or absent secretion of the parathyroid hormone (PTH). The most common therapeutic strategy to treat this condition is hormone replacement therapy with calcium and vitamin D but, unfortunately, in the long term this treatment may not be sufficient to compensate for the loss of endocrine function. Glandular autotransplantation is considered the most effective technique in place of replacement therapy. Although it leads to excellent results in most cases, autotransplantation is not always possible. Allograft is a good way to treat patients who have not been able to undergo autograft, but this technique has limited success due to side effects related to tissue rejection. This therapy is supported by systemic immunosuppression, which leads to the onset of serious side effects in patients, with a risk of endocrine toxicity. Today, research on endocrine disorders is focused on discovering alternative graft therapies that can allow optimal results with the fewest possible side effects. In this review, we will make an update on the current state of the art about the cell and tissue therapy as treatment for hypoparathyroidism, to identify which type of therapeutic strategy could be valid for a future clinical use.

A hydroxytyrosol (HTyr)-enriched fraction containing HTyr 6% w/w, derived from Olea europaea L. byproducts and obtained using an environmentally and economically sustainable technology, was lipophilized under green chemistry conditions. The effects of three fractions containing hydroxytyrosyl butanoate, octanoate, and oleate, named, respectively, lipophilic fractions 5, 6, and 7, and unreacted HTyr on the human colon cancer cell line HCT8-β8 engineered to overexpress estrogen receptor β (ERβ) were evaluated and compared to those of pure HTyr. The experimental data demonstrated that HTyr and all fractions showed an antiproliferative effect, as had been observed by the evaluation of the cellular doubling time under these different conditions (mean control, 32 ± 4 h; HTyr 1, 65 ± 9 h; fraction 5, 64 ± 11 h; fraction 6, 62 ± 14 h; fraction 7, 133 ± 30 h). As evidenced, fraction 7 containing hydroxytyrosyl oleate showed the highest activity. These results were related to the link with ER-β, which was assessed through simultaneous treatment with an inhibitor of ERβ.

The increasing interest on microRNAs (miRNAs), small non-coding RNA molecules containing about 22 nucleotides, about their biological functions led researchers to discover that they are actively involved in several biological processes. In the last decades, miRNAs become one of the most topic of cancer research. miRNAs, thanks to their function, are the perfect molecules to modulate multiple signaling pathways and gene expression in cancer, with the consequent capacity to modulate cancerous processes, such as cellular proliferation, invasion, metastasis and chemoresistance in various tumours. In the last years, several studies have demonstrated the role of miRNAs in their pathophysiology, but little we know about the underlying mechanism that lead to bone tumours like chondrosarcoma (COS), giant cell tumour of bone (GCTB) and Ewing sarcoma (EWS) to still be highly aggressive and resistant tumours. An exploration of the role of miRNAs in the biology of them will permit to researchers to find new molecular mechanisms that can be used to develop new and more effective therapies against these bone tumours. Here we present a comprehensive study of the latest discoveries which have been performed in relation to the role of miRNAs in the neoplastic processes which characterize COS, EWS and GCTB, demonstrating how these tiny molecules can act as tumour promoters or as tumour suppressors and how they can be used for improving therapeutic approaches.

Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited tumor syndrome, characterized by the development of multiple neuroendocrine tumors (NETs) in a single patient. Major manifestations include primary hyperparathyroidism, gastro-entero-pancreatic neuroendocrine tumors, and pituitary adenomas. In addition to these main NETs, various combinations of more than 20 endocrine and non-endocrine tumors have been described in MEN1 patients. Despite advances in diagnostic techniques and treatment options, which are generally similar to those of sporadic tumors, patients with MEN1 have a poor life expectancy, and the need for targeted therapies is strongly felt. MEN1 is caused by germline heterozygous inactivating mutations of the MEN1 gene, which encodes menin, a tumor suppressor protein. The lack of a direct genotype–phenotype correlation does not permit the determination of the exact clinical course of the syndrome. One of the possible causes of this lack of association could be ascribed to epigenetic factors, including microRNAs (miRNAs), single-stranded non-coding small RNAs that negatively regulate post-transcriptional gene expression. Some miRNAs, and their deregulation, have been associated with MEN1 tumorigenesis. Recently, an extracellular class of miRNAs has also been identified (c-miRNAs); variations in their levels showed association with various human diseases, including tumors. The aim of this review is to provide a general overview on the involvement of miRNAs in MEN1 tumor development, to be used as possible targets for novel molecular therapies. The potential role of c-miRNAs as future non-invasive diagnostic and prognostic biomarkers of MEN1 will be discussed as well.

Osteoporosis is a multifactorial skeletal disease that is associated with both bone mass decline and microstructure damage. The fragility fractures—especially those affecting the femur—that embody the clinical manifestation of this pathology continue to be a great medical and socioeconomic challenge worldwide. The currently available diagnostic tools, such as dual energy X-ray absorptiometry, Fracture Risk Assessment Tool (FRAX) score, and bone turnover markers, show limited specificity and sensitivity; therefore, the identification of alternative approaches is necessary. As a result of their advantageous features, such as non-invasiveness, biofluid stability, and easy detection, circulating cell-free miRs are promising new potential biomarkers for the diagnosis of osteoporosis and low-traumatic fracture risk assessment. However, due to the absence of both standardized pre-analytical, analytical, and post-analytical protocols for their measurement and universally accepted guidelines for diagnostic use, their clinical utility is limited. The aim of this review was to record all the data currently available in the literature concerning the use of circulating microRNAs as both potential biomarkers for osteoporosis diagnosis and fragility fracture risk evaluation, and group them according to the experimental designs, in order to support a more conscious choice of miRs for future research in this field.

Despite the availability of multimodal and aggressive therapies, currently patients with skeletal sarcomas, including osteosarcoma and chondrosarcoma, often have a poor prognosis. In recent decades, advances in sequencing technology have revealed the presence of RNAs without coding potential known as non-coding RNAs (ncRNAs), which provides evidence that protein-coding genes account for only a small percentage of the entire genome. This has suggested the influence of ncRNAs during development, apoptosis and cell proliferation. The discovery of microRNAs (miRNAs) in 1993 underscored the importance of these molecules in pathological diseases such as cancer. Increasing interest in this field has allowed researchers to study the role of miRNAs in cancer progression. Regarding skeletal sarcomas, the research surrounding which miRNAs are involved in the tumourigenesis of osteosarcoma and chondrosarcoma has rapidly gained traction, including the identification of which miRNAs act as tumour suppressors and which act as oncogenes. In this review, we will summarize what is new regarding the roles of miRNAs in chondrosarcoma as well as the latest discoveries of identified miRNAs in osteosarcoma.

Osteosarcoma (OSA) is the most common primary malignant bone tumor, usually arising in the long bones of children and young adults. There are different subtypes of OSA, among which we find the conventional OS (also called medullary or central osteosarcoma) which has a high grade of malignancy and an incidence of 80%. There are different subtypes of high grade OS like chondroblastic, fibroblastic, osteoblastic, telangiectatic, and the small cell osteosarcoma (SCO). In this study, for the first time, we have isolated, established, and characterized a cell line of cancer stem cells (CSCs) from a human SCO. First of all, we have established a primary finite cell line of SCO, from which we have isolated the CSCs by the sphere formation assay. We have proved theirin vitromesenchymal and embryonic stem phenotype. Additionally, we have showed their neoplastic phenotype, since the original tumor bulk is a high grade osteosarcoma. This research demonstrates the existence of CSCs also in human primary SCO and highlights the establishment of this particular stabilized cancer stem cell line. This will represent a first step into the study of the biology of these cells to discover new molecular targets molecules for new incisive therapeutic strategies against this highly aggressive OSA.

The current improvements in therapy against osteosarcoma (OS) have prolonged the lives of cancer patients, but the survival rate of five years remains poor when metastasis has occurred. The Cancer Stem Cell (CSC) theory holds that there is a subset of tumor cells within the tumor that have stem-like characteristics, including the capacity to maintain the tumor and to resist multidrug chemotherapy. Therefore, a better understanding of OS biology and pathogenesis is needed in order to advance the development of targeted therapies to eradicate this particular subset and to reduce morbidity and mortality among patients. Isolating CSCs, establishing cell cultures of CSCs, and studying their biology are important steps to improving our understanding of OS biology and pathogenesis. The establishment of human-derived OS-CSCs from biopsies of OS has been made possible using several methods, including the capacity to create 3-dimensional stem cell cultures under nonadherent conditions. Under these conditions, CSCs are able to create spherical floating colonies formed by daughter stem cells; these colonies are termed "cellular spheres". Here, we describe a method to establish CSC cultures from primary cell cultures of conventional OS obtained from OS biopsies. We clearly describe the several passages required to isolate and characterize CSCs.

Development of tools to be used forin vivobone tissue regeneration focuses on cellular models and differentiation processes. In searching for all the optimal sources, adipose tissue-derived mesenchymal stem cells (hADSCs or preadipocytes) are able to differentiate into osteoblasts with analogous characteristics to bone marrow mesenchymal stem cells, producing alkaline phosphatase (ALP), collagen, osteocalcin, and calcified nodules, mainly composed of hydroxyapatite (HA). The possibility to influence bone differentiation of stem cells encompasses local and systemic methods, including the use of drugs administered systemically. Among the latter, strontium ranelate (SR) represents an interesting compound, acting as an uncoupling factor that stimulates bone formation and inhibits bone resorption. The aim of our study was to evaluate thein vitroeffects of a wide range of strontium (Sr2+) concentrations on proliferation, ALP activity, and mineralization of a novel finite clonal hADSCs cell line, named PA20-h5. Sr2+promoted PA20-h5 cell proliferation while inducing the increase of ALP activity and gene expression as well as HA production duringin vitroosteoinduction. These findings indicate a role for Sr2+in supporting bone regeneration during the process of skeletal repair in general, and, more specifically, when cell therapies are applied.

AIM: To investigate the effects of quercetin and genistein on colon cancer cell proliferation and their estrogen receptor β (ERβ) expression. METHODS: Colon cancer cells were stably transfected with a mammalian expression vector to overexpress ERβ (HCT8-β8-expressing cells) or a control vector (HCT8-pSV2neo-expressing cells). The proliferation of these cells was examined after treatment with quercetin or genistein (5-100 μmol/L), or 10 nmol/L 17β-estradiol (17β-E2). Cell viability was examined by acridine orange staining following treatments for 48 or 144 h. Effects of quercetin and genistein on ERβ transcriptional transactivation were examined by luciferase activity in HCT8-β8-expressing cells transiently transfected with a pEREtkLUC reporter vector. In addition, the regulation of ERβ transcription by phytoestrogens and 17β-E2 was examined by quantitative polymerase chain reaction. RESULTS: Proliferation of HCT8-β8-expressing cells was not reduced low doses (5 μmol/L) of quercetin and genistein, while it was reduced at 25-50 μmol/L with an effect similar to 10 nmol/L 17β-E2. Treatment with doses of phytoestrogens ≥ 75 μmol/L completely blocked cell growth and reduced overall cell counts, however no effects at any dose were observed in HCT8-pSV2neo-expressing cells. These results were supported by viability staining that revealed acridine orange-stained lysosomes with high doses or extended treatment periods. Genistein and quercetin (50 μmol/L) significantly increased ER-responsive luciferase activity similar to 10 nmol/L 17β-E2 (P < 0.05). Furthermore, genistein and quercetin (50 μmol/L), as well as 10 nmol/L 17β-E2 significantly increased ERβ mRNA levels in HCT8-β8-expressing cells (P < 0.05). In addition, treatment of HCT8-pSV2neo-expressing cells with 50 µmol/L quercetin or 10 nmol/L 17β-E2 significantly increased ERβ mRNA levels compared to untreated controls (P < 0.05), though the absolute levels were much lower than in HCT8-β8-expressing cells. CONCLUSION: The antitumorigenic effects of the phytoestrogenic compounds quercetin and genistein on colon cancers cells occur through ERβ activity and expression.

Skeletal muscle has an outstanding capacity for regeneration in response to injuries, but there are disorders in which this process is seriously impaired, such as sarcopenia. Pharmacological treatments to restore muscle trophism are not available, therefore, the identification of suitable therapeutic targets that could be useful for the treatment of skeletal reduced myogenesis is highly desirable. In this in vitro study, we explored the expression and function of the calcium-sensing receptor (CaSR) in human skeletal muscle tissues and their derived satellite cells. The results obtained from analyses with various techniques of gene and protein CaSR expression and of its secondary messengers in response to calcium (Ca2+) and CaSR drugs have demonstrated that this receptor is not present in human skeletal muscle tissues, neither in the established satellite cells, nor during in vitro myogenic differentiation. Taken together, our data suggest that, although CaSR is a very important drug target in physiology and pathology, this receptor probably does not have any physiological role in skeletal muscle in normal conditions.