Bone turnover markers in serum and urine as diagnostic, prognostic and monitoring biomarkers of bone metastasis

Bone aging and extracellular vesicles

Bone aging, a major global health concern, is the natural decline in bone mass and strength. Concurrently, extracellular vesicles (EVs), tiny membrane-bound particles produced by cells, have gained recognition for their roles in various physiological processes and age-related diseases. The interaction between EVs and bone aging is of growing interest, particularly their effects on bone metabolism, which become increasingly critical with advancing age. In this review, we explored the biology, types, and functions of EVs and emphasized their regulatory roles in bone aging. We examined the effects of EVs on bone metabolism and highlighted their potential as biomarkers for monitoring bone aging progression. Furthermore, we discussed the therapeutic applications of EVs, including targeted drug delivery and bone regeneration, and addressed the challenges associated with EV-based therapies, including the technical complexities and regulatory issues. We summarized the current research and clinical trials investigating the role of EVs in bone aging and suggested future research directions. These include the potential for personalized medicine using EVs and the integration of EV research with advanced technologies to enhance the management of age-related bone health. This analysis emphasized the transformative potential of EVs in understanding and managing bone aging, thereby marking a significant advancement in skeletal health research.

Bone turnover markers and muscle decay indicator in patients with proximal femur fracture - a case-control study

Introduction

Fracture of the proximal femur is common in elderly patients, in fact threatening their lives. Age-related sarcopenia may be involved in the imbalance resulting in the injury. Handy and readily accessible biochemical tests would be useful to assess the musculoskeletal system condition in daily practice. The aim of the study was to determine whether there is any relation between muscle decay and fracture of the proximal femur and to assess bone quality in elderly patients.

Material and methods

In the study 22 patients who represented the treatment group were hospitalized due to proximal femur fracture. Eighteen patients from the control group with no fracture in their history were admitted to the Internal Medicine Department. Anyone treated for osteoporosis, immune disease affecting protein balance, neoplasm, mental illness, heart failure, or myocardial infarction was excluded from the study. In every case a blood sample from an elbow vein was drawn, collected in EDTA-K2 tubes, and then centrifuged to separate plasma from the whole blood. Subsequently, the concentrations of C-terminal cross-linked telopeptide of type I collagen (CTX-I), sex hormone binding globulin (SHBG) and creatine kinase (CK) in plasma were determined using commercial enzyme-linked immunosorbent assays.

Results

The CK plasma concentration differed between the patient groups (p = 0.011). The SHBG plasma concentration was significantly higher in the treatment group (p = 0.006), whereas a slight difference in CTX-I plasma concentration between the groups was found (p = 0.038). No significant correlations between plasma CK, SHBG or CTX-I were found (p > 0.05).

Conclusions

Creatine kinase is actually not an appropriate marker for the clinical assessment of muscle tissue quality in patients with or at risk of proximal femur fracture. Analyzing the quality of bone tissue, we can conclude it was poorer in patients with proximal femur fracture than in the control group.

MDA-9/Syntenin in the tumor and microenvironment defines prostate cancer bone metastasis

Bone metastasis is a frequent and incurable consequence of advanced prostate cancer (PC). An interplay between disseminated tumor cells and heterogeneous bone resident cells in the metastatic niche initiates this process. Melanoma differentiation associated gene-9 (mda-9/Syntenin/syndecan binding protein) is a prometastatic gene expressed in multiple organs, including bone marrow-derived mesenchymal stromal cells (BM-MSCs), under both physiological and pathological conditions. We demonstrate that PDGF-AA secreted by tumor cells induces CXCL5 expression in BM-MSCs by suppressing MDA-9-dependent YAP/MST signaling. CXCL5-derived tumor cell proliferation and immune suppression are consequences of the MDA-9/CXCL5 signaling axis, promoting PC disease progression. mda-9 knockout tumor cells express less PDGF-AA and do not develop bone metastases. Our data document a previously undefined role of MDA-9/Syntenin in the tumor and microenvironment in regulating PC bone metastasis. This study provides a framework for translational strategies to ameliorate health complications and morbidity associated with advanced PC.

Diagnostic value of alkaline phosphatase and bone-specific alkaline phosphatase for metastases in breast cancer: a systematic review and meta-analysis

PURPOSE

Numerous studies had reported the diagnostic value of alkaline phosphatase (ALP) and its bone-specific isoforms (BAP) in the metastases of breast cancer (BC). The purpose of this meta-analysis was to summarize the diagnostic value of serum ALP and BAP in metastatic BC, especially focused on bone metastases.

METHODS

We searched comprehensively in the PubMed, Cochrane Library, and EMBASE for studies to explore the diagnostic accuracy of serum ALP/BAP level for metastatic BC. Qualities of including studies were assessed and pooled sensitivity, specificity, and summary receiver operating characteristic curve were calculated. Publication bias was assessed and meta-regression was conducted.

RESULTS

We finally included 25 studies with a total of 12,155 BC patients (1681 metastatic cases and 10,474 controls). According to the QUADAS-2 tool to assessment the methodological quality, most of the included studies were judged as high risk of patient selection bias. High serum levels of ALP/BAP in bone metastatic BC patients could be found compared with non-metastatic BC patients. The pooled sensitivity and specificity of ALP for BC bone metastases were 0.62 and 0.86, and the area under the curve (AUC) was 0.80. The pooled sensitivity and specificity of ALP for all site metastases (mainly bone and liver) were 0.56 and 0.91, and the AUC was 0.90. The pooled sensitivity and specificity of BAP for BC bone metastases were 0.66 and 0.92, and the AUC was 0.89.

CONCLUSION

Although not promising, serum ALP and BAP could bring useful information for the early detection of BC metastases especially for the bone metastases.

Negative impact on bone homeostasis in postmenopausal women with non-metastatic breast cancer during cytotoxic chemotherapy

INTRODUCTION

The burden and mechanisms of endocrine therapy-related bone loss are well known, while there are limited data on chemotherapy-induced bone resorption. The study aimed to evaluate the effect of cytotoxic chemotherapy on bone homeostasis among postmenopausal women with non-metastatic breast cancer.

MATERIALS AND METHODS

Early and locally advanced postmenopausal non-metastatic breast cancer patients aged 45 to 65 planned for three cycles of anthracycline and four cycles of taxane chemotherapy administered along with dexamethasone (cumulative dose-256 mg) as an antiemetic from June 2018 to December 2021 were included. Bone mineral density (BMD), bone turnover markers, calciotropic hormones, pro-inflammatory cytokines, oxidative stress, and total antioxidant levels (TAS) were measured.

RESULTS

We recruited 109 patients, with early 34 (31.2%) and locally advanced breast cancer 75 (68.8%) with median age 53 (45-65) years. There was a significant decrease in the % BMD at the lumbar spine, neck of the femur, and total hip post-chemotherapy. There was a significant increase in serum C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) levels post-chemotherapy. PINP/CTX ratio significantly decreased post-chemotherapy. Serum 25-OH vitamin D was significantly reduced with a compensatory increase in plasma iPTH levels. The change in CTX, PINP/CTX ratio, 25-OH vitamin D, iPTH, and oxidative stress index was more pronounced during anthracycline as taxane chemotherapy. There were no significant changes in pro-inflammatory cytokine levels.

CONCLUSION

Chemotherapy and dexamethasone as antiemetic resulted in significant bone loss, as evidenced by bone turnover markers. Further studies are required to understand the mechanism of chemotherapy-induced bone loss and the need for bone-strengthening agents during chemotherapy.

Tumor Microenvironment, Clinical Features, and Advances in Therapy for Bone Metastasis in Gastric Cancer

Gastric cancer (GC) is one of the most malignant neoplasms worldwide, accounting for about 770,000 deaths in 2020. The incidence of gastric cancer bone metastasis (GC-BM) is low, about 0.9-13.4%, and GC patients develop GC-BM because of a suitable bone microenvironment. Osteoblasts, osteoclasts, and tumor cells interact with each other, secreting cytokines such as PTHrP, RANK-L, IL-6, and other growth factors that disrupt the normal bone balance and promote tumor growth. The functions and numbers of immune cells in the bone microenvironment are continuously inhibited, resulting in bone balance disorder due to the cytokines released from destroyed bone and growing tumor cells. Patients with GC-BM are generally younger than 65 years old and they often present with a later stage of the disease, as well as more aggressive tumors. They usually have shorter overall survival (OS) because of the occurrence of skeletal-related events (SREs) and undetected bone destruction due to the untimely bone inspection. Current treatments of GC-BM focus mainly on gastric cancer and SRE-related treatment. This article reviews the clinical features, possible molecular pathogeneses, and the most commonly used diagnostic methods and treatments of bone metastasis in gastric cancer.

Deep Learning for the Automatic Diagnosis and Analysis of Bone Metastasis on Bone Scintigrams

OBJECTIVE

To develop an approach for automatically analyzing bone metastases (BMs) on bone scintigrams based on deep learning technology.

METHODS

This research included a bone scan classification model, a regional segmentation model, an assessment model for tumor burden and a diagnostic report generation model. Two hundred eighty patients with BMs and 341 patients with non-BMs were involved. Eighty percent of cases were randomly extracted from two groups as training set. Remaining cases were as testing set. A deep residual convolutional neural network with different structures was used to determine whether metastatic bone lesions existed, regions of lesions were automatically segmented. Bone scan tumor burden index (BSTBI) was calculated; finally, diagnostic report could be automatically generated. The sensitivity, specificity and accuracy of classification model were compared with three physicians with different clinical experience. The Dice coefficient evaluated the effect of segmentation model and compared to the result of nnU-Net model. The correlation between BSTBI and blood alkaline phosphatase (ALP) level was analyzed to verify the efficiency of BSTBI. The performance of report generation model was evaluated by the accuracy of interpretation of report.

RESULTS

In testing set, the sensitivity, specificity and accuracy of classification model were 92.59%, 85.51% and 88.62%, respectively. The accuracy showed no statistical difference with moderately and experienced physicians and obviously outperformed the inexperienced. The Dice coefficient of BMs area was 0.7387 in segmentation stage. Based on the whole model frame, our segmentation model outperformed the nnU-Net. BSTBI value changed as the BMs changed. There was a positive correlation between BSTBI and ALP level. The accuracy of report generation model was 78.05%.

CONCLUSION

Deep learning based on automatic analysis frameworks for BMs can accurately identify BMs, preliminarily realize a fully automatic analysis process from raw data to report generation. BSTBI can be used as a quantitative evaluation indicator to assess the effect of therapy on BMs in different patients or in the same patient before and after treatment.

Insulin-like growth factor-1 positively associated with bone formation markers and creatine kinase in adults with general physical activity

BACKGROUND

The Insulin-like growth factor-1 (IGF-1) is primarily synthesized by hepatocytes in a growth hormone (GH)-dependent manner, it is also produced by bone and muscle. The effects of exercise on the associations between IGF-1 levels and bone turnover markers (BTM) were found in the previous studies. However, the associations between the levels of IGF-1 and BTM, liver function tests, and skeletal muscle markers in adults with general physical activity were not clear.

METHODS

Ninety-four participants were recruited from healthy survey. Blood samples were collected to analyze the levels of IGF-1, total protein (TP), albumin (Alb), total bilirubin (T-Bil), direct bilirubin (D-Bil), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), bone alkaline phosphatase (BALP), lactate dehydrogenase (LDH), creatine kinase (CK), creatinine (CRTN), and glucose. Urine samples were collected to analyze the CRTN and deoxypyridinoline (Dpd) levels.

RESULTS

The positively significant associations were found between the IGF-1 levels and the levels of ALP, BALP, and CK, respectively. No significant associations were found between the IGF-1 levels and the levels of TP, Alb, A/G, T-Bil, D-Bil, AST, ALT, LDH, glucose, urinary CRTN, urinary Dpd, and Dpd/CRTN ratios, respectively.

CONCLUSION

The serum IGF-1 levels associated with the levels of skeletal muscle and bone formation markers (BFM), not the bone resorption markers under general physical activity in the healthy adults. The physician needs to consider the effects of bone formation and skeletal muscle markers on the IGF-1 levels in the management of IGF-1-related disorders.

Bone metastasis: mechanisms, therapies, and biomarkers

Skeletal metastases are frequent complications of many cancers, causing bone complications (fractures, bone pain, disability) that negatively affect the patient's quality of life. Here, we first discuss the burden of skeletal complications in cancer bone metastasis. We then describe the pathophysiology of bone metastasis. Bone metastasis is a multistage process: long before the development of clinically detectable metastases, circulating tumor cells settle and enter a dormant state in normal vascular and endosteal niches present in the bone marrow, which provide immediate attachment and shelter, and only become active years later as they proliferate and alter the functions of bone-resorbing (osteoclasts) and bone-forming (osteoblasts) cells, promoting skeletal destruction. The molecular mechanisms involved in mediating each of these steps are described, and we also explain how tumor cells interact with a myriad of interconnected cell populations in the bone marrow, including a rich vascular network, immune cells, adipocytes, and nerves. We discuss metabolic programs that tumor cells could engage with to specifically grow in bone. We also describe the progress and future directions of existing bone-targeted agents and report emerging therapies that have arisen from recent advances in our understanding of the pathophysiology of bone metastases. Finally, we discuss the value of bone turnover biomarkers in detection and monitoring of progression and therapeutic effects in patients with bone metastasis.

Antipostmenopausal effects of Stauntonia hexaphylla and Vaccinium bracteatum fruit combination in estrogen-deficient rats

Background

Climacterium is a series of physical and mental symptoms occurring in women and men due to decreased levels of sex hormones. Women lose the ability to become pregnant due to decreased ovarian estrogen production; the initial symptom being hot flushes. In addition, urogenital atrophy, sexual dysfunction, mood changes, and osteoporosis occur. Extracts of Stauntonia hexaphylla (SH) and Vaccinium bracteatum (VB) fruits, with a wide range of biological activities, are widely used in traditional herbal medicine.

Objective

The purpose of this study was to investigate the mitigation of menopausal symptoms, such as hot flushes and postmenopausal osteoporosis after combinatorial treatment with SH and VB (SHVB) of ovariectomized (OVX) rats.

Design

We measured the bone regenerative effect of SHVB on receptor activator of nuclear factor-κB (NF-κB) ligand-induced osteoclast differentiation in vitro and on ovariectomy-induced osteoporosis in vivo. We investigated the effect of SHVB in a rat model of menopausal hot flushes, in which the tail skin temperature increases following ovariectomy-induced rapid decline in estrogen levels.

Results

SHVB inhibited osteoclast formation and tartrate-resistant acid phosphatase activity in primary mouse bone marrow-derived cells. In an estrogen deficiency-induced rat model, measurement of serum bone turnover factors showed that treatment with SHVB lowered the increased bone turnover. Additionally, SHVB decreased OVX-induced bone loss of the total femur. SHVB inhibited osteoclast differentiation, prevented bone mass reduction, and improved trabecular bone structure and biochemical markers in OVX-induced osteoporosis. In addition, administration of SHVB significantly ameliorated the changes in skin temperature in OVX rats.

Conclusion

SHVB improved the symptoms of menopause. These results provide the foundation for developing SHVB as a natural substance to replace hormones in the future.

Effects of cabozantinib on bone turnover markers in real-world metastatic renal cell carcinoma

BACKGROUND

Cabozantinib strongly inhibits osteoclast differentiation and bone resorption in vitro. We aimed to evaluate its effect on bone turnover markers (BTMs) in metastatic renal cell carcinoma.

METHODS

This is a monocentric prospective study on patients with mRCC treated with cabozantinib between October 2016 and July 2018. We collected blood samples at baseline and after 3 and 6 months of treatment. We compared sets of data obtained from plasma samples in the whole population with unpaired 2-tailed Student t tests and data for a subset of patients for which all timepoints were available with paired 2-tailed Student t tests. We used the Kaplan-Meier method for survival analyses and the log-rank test to compare the curves.

RESULTS

Our analysis included 39 patients. At month 3, the mean C-terminal cross-linked telopeptides of type I collagen (CTx) and the mean N-terminal propeptide of type 1 collagen (PINP) levels were significantly decreased in the whole population (p = 0.013 and p < 0.0001, respectively), as well as at paired analysis (p = 0.015 and p = 0.045, respectively). No differences were observed between baseline and 6 months (p = 0.053 and p = 0.087, respectively). After 3 months, the mean parathyroid hormone (PTH) levels significantly increased in the whole population (p = 0.004), as well as at paired analysis; the mean PTH levels increased significantly at 3 and 6 months, respectively (p = 0.019 and p = 0.041, respectively). Changes in BTM levels were not associated with outcome.

CONCLUSIONS

Cabozantinib significantly reduced bone resorption as demonstrated by the decrease of CTx and showed a transient secondary increase of PTH.

An Update on the Prognostic and Predictive Serum Biomarkers in Metastatic Prostate Cancer

Serum biomarkers are molecules produced by normal and abnormal cells. Prostate specific antigen (PSA) is an example of a serum biomarker used widely in the diagnosis and prognostication of prostate cancer. PSA has its limitations as it is organ- but not cancer-specific. The aim of this review is to summarize the current published data on the potential prognostic and predictive biomarkers in metastatic prostate cancer (mPC) that can be used in conjunction with PSA. These biomarkers include microRNAs, androgen receptor variants, bone metabolism, neuroendocrine and metabolite biomarkers, and could guide treatment selection and sequence in an era where we strive to personalized therapy.

Current and Emerging Biomarkers Predicting Bone Metastasis Development

Bone is one of the preferential sites of distant metastases from malignant tumors, with the highest prevalence observed in breast and prostate cancers. Patients with bone metastases (BMs) may experience skeletal-related events, such as severe bone pain, pathological fractures, spinal cord compression, and hypercalcemia, with negative effects on the quality of life. In the last decades, a deeper understanding of the molecular mechanisms underlying the BM onset has been gained, leading to the development of bone-targeting agents. So far, most of the research has been focused on the pathophysiology and treatment of BM, with only relatively few studies investigating potential predictors of risk for BM development. The ability to select such "high-risk" patients could allow early identification of those most likely to benefit from interventions to prevent or delay BM. This review summarizes several evidences for the potential use of specific biomarkers able to predict early the BM development.

Skeletal Metastases of Unknown Primary: Biological Landscape and Clinical Overview

Skeletal metastases of unknown primary (SMUP) represent a clinical challenge in dealing with patients diagnosed with bone metastases. Management of these patients has improved significantly in the past few years. however, it is fraught with a lack of evidence. While some patients have achieved impressive gains, a more systematic and tailored treatment is required. Nevertheless, in real-life practice, the outlook at the beginning of treatment for SMUP is decidedly somber. An incomplete translational relevance of pathological and clinical data on the mortality and morbidity rate has had unsatisfactory consequences for SMUP patients and their physicians. We examined several approaches to confront the available evidence; three key points emerged. The characterization of the SMUP biological profile is essential to driving clinical decisions by integrating genetic and molecular profiles into a multi-step diagnostic work-up. Nonetheless, a pragmatic investigation plan and therapy of SMUP cannot follow a single template; it must be adapted to different pathophysiological dynamics and coordinated with efforts of a systematic algorithm and high-quality data derived from statistically powered clinical trials. The discussion in this review points out that greater efforts are required to face the unmet needs present in SMUP patients in oncology.

Membrane-Based Microwave-Mediated Electrochemical Immunoassay for the In Vitro, Highly Sensitive Detection of Osteoporosis-Related Biomarkers

Highly sensitive and multiplexed in vitro detection of osteoporosis-related biochemical markers were carried out based on the membrane-based microwave-mediated electrochemical immunoassay (MMeEIA), where we can dramatically reduce the sample preparation time by shortening the incubation time of conjugation to obtain sensitive detection based on three dimensional conjugation of antibodies with target antigens in nylon membrane disk. C-terminal cross-linked telopeptide of type I collagen (CTx), Osteocalcin (OC), parathyroid hormone (PTH), and N-terminal propeptide of type I collagen (P1NP), which can be utilized to monitor the progress of osteoporosis, were quantified using their corresponding antibody immobilized in membranes. Coefficient of variations in this intra- and inter-assays were within 8.0% for all markers. When compared with data obtained from clinically used standard equipment (Roche modular E170), their coefficients of determination, R² values, are mostly more than 0.9. They show that the results obtained from MMeEIA are in good agreement with that from the conventional clinical instruments.

Breast Cancer Recurrence Risk Assessment: Is Non-Invasive Monitoring an Option?

BACKGROUND

Metastatic breast cancer (MBC) represents a life-threatening disease with a median survival time of 18-24 months that often can only be treated palliatively. The majority of women suffering from MBC are those who had been previously diagnosed with locally advanced disease and subsequently experienced cancer recurrence in the form of metastasis. However, according to guidelines, no systemic follow-up for monitoring purposes is recommended for these women. The purpose of this article is to review current methods of recurrent risk assessment as well as non-invasive monitoring options for women at risk for distant disease relapse and metastasis formation.

METHODS

We used PubMed and national guidelines, such as the National Comprehensive Cancer Network (NCCN), to find recently published studies on breast cancer recurrence risk assessment and systemic monitoring of breast cancer patients through non-invasive means.

RESULTS

The options for recurrence risk assessment of locally invasive breast cancer has improved due to diverse genetic tests, such as Oncotype DX, MammaPrint, the PAM50 (now known as the "Prosigna Test") assay, EndoPredict (EP), and the Breast Cancer Index (BCI), which evaluate a women's risk of relapse according to certain cancer-gene expression patterns. Different promising non-invasive urinary protein-based biomarkers with metastasis surveillance potential that have been identified are MMP-2, MMP-9, NGAL, and ADAM12. In particular, ααCTX, ββCTX, and NTX could help to monitor bone metastasis.

CONCLUSION

In times of improved recurrence risk assessment of women with breast cancer, non-invasive biomarkers are urgently needed as potential monitoring options for women who have an increased risk of recurrence. Urine as a bioliquid of choice provides several advantages - it is non-invasive, can be obtained easily and frequently, and is economical. Promising biomarkers that could help to follow up women with increased recurrence risk have been identified. In order for them to be implemented in clinical usage and national guideline recommendations, further validation in larger independent cohorts will be needed.

[Risk Factors of Non-small Cell Lung Cancer with Bone Metastasis after Therapy]

背景与目的

肺癌目前是死亡率最高的肿瘤, 非小细胞肺癌(non-small cell lung cancer, NSCLC)患者在手术后通常会发生远处转移, 如骨转移、脑转移、肺转移等。本研究旨在探究NSCLC患者术后发生骨转移的危险因素。

方法

选择本院于2009年5月-2011年5月确诊收治的NSCLC患者176例, 按照是否发生骨转移将患者分为两组, 即骨转移组和无骨转移组。对比两组患者的一般临床病理资料, 并通过多因素分析对比发生骨转移的独立危险因素。

结果

NSCLC患者的一般临床病理资料中血栓与否, 肿瘤-淋巴结-转移(tumor-node-metastasis, TNM)分期与是否发生骨转移关系密切, 有统计学意义(均P < 0.01);在两组患者的凝血功能指标中发现凝血酶原时间、活化部分凝血酶活酶时间、纤维蛋白原、凝血酶时间、血小板计数、D-二聚体以及碱性磷酸酶之间存在明显的差异性, 有统计学意义(均P < 0.05);Logistic回归分析发现纤维蛋白原、碱性磷酸酶、T4期、N3期和D-二聚体为NSCLC患者发生骨转移的独立危险因素。

结论

纤维蛋白原、活化部分凝血酶活酶时间、碱性磷酸酶、T3期、N2期和D-二聚体为NSCLC患者发生骨转移的独立危险因素。

Bone Cell Activity in Clinical Prostate Cancer Bone Metastasis and Its Inverse Relation to Tumor Cell Androgen Receptor Activity

Advanced prostate cancer frequently metastasizes to bone and induces a mixed osteoblastic/osteolytic bone response. Standard treatment for metastatic prostate cancer is androgen-deprivation therapy (ADT) that also affects bone biology. Treatment options for patients relapsing after ADT are limited, particularly in cases where castration-resistance does not depend on androgen receptor (AR) activity. Patients with non-AR driven metastases may, however, benefit from therapies targeting the tumor microenvironment. Therefore, the current study specifically investigated bone cell activity in clinical bone metastases in relation to tumor cell AR activity, in order to gain novel insight into biological heterogeneities of possible importance for patient stratification into bone-targeting therapies. Metastasis tissue obtained from treatment-naïve (n = 11) and castration-resistant (n = 28) patients was characterized using whole-genome expression analysis followed by multivariate modeling, functional enrichment analysis, and histological evaluation. Bone cell activity was analyzed by measuring expression levels of predefined marker genes representing osteoclasts (ACP5, CTSK, MMP9), osteoblasts (ALPL, BGLAP, RUNX2) and osteocytes (SOST). Principal component analysis indicated a positive correlation between osteoblast and osteoclast activity and a high variability in bone cell activity between different metastases. Immunohistochemistry verified a positive correlation between runt-related transcription factor 2 (RUNX2) positive osteoblasts and tartrate-resistant acid phosphatase (TRAP, encoded by ACP5) positive osteoclasts lining the metastatic bone surface. No difference in bone cell activity was seen between treatment-naïve and castration-resistant patients. Importantly, bone cell activity was inversely correlated to tumor cell AR activity (measured as AR, FOXA1, HOXB13, KLK2, KLK3, NKX3-1, STEAP2, and TMPRSS2 expression) and to patient serum prostate-specific antigen (PSA) levels. Functional enrichment analysis indicated high bone morphogenetic protein (BMP) signaling in metastases with high bone cell activity and low tumor cell AR activity. This was confirmed by BMP4 immunoreactivity in tumor cells of metastases with ongoing bone formation, as determined by histological evaluation of van Gieson-stained sections. In conclusion, the inverse relation observed between bone cell activity and tumor cell AR activity in prostate cancer bone metastasis may be of importance for patient response to AR and/or bone targeting therapies, but needs to be evaluated in clinical settings in relation to serum markers for bone remodeling, radiography and patient response to therapy. The importance of BMP signaling in the development of sclerotic metastasis lesions deserves further exploration.

An in vitro 3D bone metastasis model by using a human bone tissue culture and human sex-related cancer cells

One of the main limitations, when studying cancer-bone metastasis, is the complex nature of the native bone environment and the lack of reliable, simple, inexpensive models that closely mimic the biological processes occurring in patients and allowing the correct translation of results. To enhance the understanding of the mechanisms underlying human bone metastases and in order to find new therapies, we developed an in vitro three-dimensional (3D) cancer-bone metastasis model by culturing human breast or prostate cancer cells with human bone tissue isolated from female and male patients, respectively. Bone tissue discarded from total hip replacement surgery was cultured in a rolling apparatus system in a normoxic or hypoxic environment. Gene expression profile, protein levels, histological, immunohistochemical and four-dimensional (4D) micro-CT analyses showed a noticeable specificity of breast and prostate cancer cells for bone colonization and ingrowth, thus highlighting the species-specific and sex-specific osteotropism and the need to widen the current knowledge on cancer-bone metastasis spread in human bone tissues. The results of this study support the application of this model in preclinical studies on bone metastases and also follow the 3R principles, the guiding principles, aimed at replacing/reducing/refining (3R) animal use and their suffering for scientific purposes.

Hypercalcemia of malignancy treated with cinacalcet

Hypercalcemia of malignancy is the most common cause of hypercalcemia in hospitalized patients. It is associated with a poor prognosis, since it reflects an advanced cancer stage. Among all cancer in females, breast cancer is the most common malignancy, and it has the highest prevalence of hypercalcemia. Approximately 70% of patients with breast cancer have bone metastases and 10% of them will have hypercalcemia as a complication at some point in the disease. Herein, we report a 69-year-old female patient with metastatic breast cancer, who developed severe hypercalcemia in the course of her disease and was diagnosed with humoral hypercalcemia of malignancy (HHM). Intense hydration along with corticoisteroids and antiresorptive medication (calcitonin, bisphosphonates and denosumab) were administered to the patient. Despite the above treatment, serum calcium levels remain elevated and calcimimetic cinacalcet was added. Upon discontinuation of cinacalcet, calcium levels were raised and returned back to the normal levels following re-initiation of the calcimimetic. Her calcium level restored to normal, and she was discharged with the following medical treatment: denosumab monthly, and cinacalcet at a titrated dose of 90 mg per day. The patient is followed as an outpatient and 11 months later, her calcium level remained within the normal range.

Learning points

Hypercalcemia of malignancy is the most common cause of hypercalcemia in hospitalized patients.Breast cancer has the highest prevalence of hypercalcemia.The cornerstone of therapy remains the intense hydration and intravenous bisphosphonates (preferably zoledronic acid).In case of persistent hypercalcemia of malignancy, the administration of calcimimetic cinacalcet could be an additional effective therapeutic option.

High uric acid (UA) downregulates bone alkaline phosphatase (BALP) expression through inhibition of its promoter activity

Bone metastases often occur in prostate cancers, lung cancers and breast cancers. Bone alkaline phosphatase (BALP) is one of the most commonly used serological markers for clinical evaluation of bone metabolism. Here, we reported that high concentrations of uric acid (UA) caused decrease of BALP levels and revealed that the effect of high concentrations of UA on the BALP expression was through inhibition of its promoter activity. Our results suggested physicians to think about serum UA status of patients with advanced cancer to avoid misdiagnosis when BALP was used to diagnose or assess the extent of bone metastases.

Changes of Bone Turnover Markers in Long Bone Nonunions Treated with a Regenerative Approach

In this clinical trial, we investigated if biochemical bone turnover markers (BTM) changed according to the progression of bone healing induced by autologous expanded MSC combined with a biphasic calcium phosphate in patients with delayed union or nonunion of long bone fractures. Bone formation markers, bone resorption markers, and osteoclast regulatory proteins were measured by enzymatic immunoassay before surgery and after 6, 12, and 24 weeks. A satisfactory bone healing was obtained in 23 out of 24 patients. Nine subjects reached a good consolidation already at 12 weeks, and they were considered as the “early consolidation” group. We found that bone-specific alkaline phosphatase (BAP), C-terminal propeptide of type I procollagen (PICP), and beta crosslaps collagen (CTX) changed after the regenerative treatment, BAP and CTX correlated to the imaging results collected at 12 and 24 weeks, and BAP variation along the healing course differed in patients who had an “early consolidation.” A remarkable decrease in BAP and PICP was observed at all time points in a single patient who experienced a treatment failure, but the predictive value of BTM changes cannot be determined. Our findings suggest that BTM are promising tools for monitoring cell therapy efficacy in bone nonunions, but studies with larger patient numbers are required to confirm these preliminary results.

Postmenopausal Iron Overload Exacerbated Bone Loss by Promoting the Degradation of Type I Collagen

117 postmenopausal women were divided into Normal, Bone loss (BL), and Osteoporosis group. Compared with Normal group (120.96 ± 43.18 μg/L), the serum ferritin (Fer) in BL (223.37 ± 130.27 μg/L) and Osteoporosis group (307.50 ± 161.48 μg/L) was significantly increased (p < 0.05). Fer level was negatively correlated with BMD (p < 0.01). TRACP levels in Osteoporosis group (4.37 ± 1.69 U/L) were significantly higher than Normal group (4.10 ± 1.60 U/L, p < 0.05). ALP levels in Osteoporosis group (112.06 ± 62.05 U/L) were significantly upregulated compared with Normal group (80.22 ± 14.94 U/L, p < 0.05). β-CTX and PINP were the degradation products of type I collagen. β-CTX levels in Osteoporosis group (667.90 ± 316.55 ng/L) were significantly increased compared with Normal group (406.06 ± 112.12 ng/L, p < 0.05). PINP levels in Osteoporosis group (78.03 ± 37.31 μg/L) were significantly higher than Normal group (37.60 ± 13.17 μg/L, p < 0.01). More importantly, there was a positive correlation between serum Fer and PINP (p < 0.01). Serum Fer showed a positive correlation of serum β-CTX (p < 0.01). The overloaded iron improved the degradation of type I collagen.

Treatment of severe hypocalcaemia due to osteoblastic metastases in a patient with post-thyroidectomy hypoparathyroidism with 153Sm-EDTMP

Symptomatic hypocalcaemia is an uncommon finding in patients with malignant tumours. We describe a patient with advanced metastatic breast cancer who developed severe hypocalcaemia caused by the combination of osteoblastic metastases and a permanent postoperative hypoparathyroidism. The patient failed to be treated with the conventional replacement therapy and was submitted effectively to radionucleotide therapy with ¹⁵³Sm.

Bone remodeling and regulating biomarkers in women at the time of breast cancer diagnosis

PURPOSE

The majority of breast cancer patients receive endocrine therapy, including aromatase inhibitors known to cause increased bone resorption. Bone-related biomarkers at the time of breast cancer diagnosis may predict future risk of osteoporosis and fracture after endocrine therapy.

METHODS

In a large population of 2,401 female breast cancer patients who later underwent endocrine therapy, we measured two bone remodeling biomarkers, TRAP5b and BAP, and two bone regulating biomarkers, RANKL and OPG, in serum samples collected at the time of breast cancer diagnosis. We analyzed these biomarkers and their ratios with patients' demographic, lifestyle, clinical tumor characteristics, as well as bone health history.

RESULTS

The presence of bone metastases, prior bisphosphonate (BP) treatment, and blood collection after chemotherapy had a significant impact on biomarker levels. After excluding these cases and controlling for blood collection time, several factors, including age, race/ethnicity, body mass index, physical activity, alcohol consumption, smoking, and hormonal replacement therapy, were significantly associated with bone biomarkers, while vitamin D or calcium supplements and tumor characteristics were not. When prior BP users were included in, recent history of osteoporosis and fracture was also associated.

CONCLUSIONS

Our findings support further investigation of these biomarkers with bone health outcomes after endocrine therapy initiation in women with breast cancer.

High serum ALP level is associated with increased risk of denosumab-related hypocalcemia in patients with bone metastases from solid tumors

Metastatic bone disease is one of the most common complications of advanced cancers. Pathological fractures, spinal cord compression, and radiotherapy or surgery to the bone are collectively called skeletal-related events (SREs), which cause severe pain, increase hospitalization rates, and impair the quality of life (QOL) of patients with bone metastases. The receptor activator of nuclear factor-kB ligand (RANKL)/RANK pathway is critical in the progression of bone metastases. Previous studies have demonstrated that an anti-RANKL antibody (denosumab) was superior to zoledronic acid in prolonging time to first SRE in patients with bone metastases from prostate and breast cancers. However, severe hypocalcemic events occur more frequently after treatment with denosumab compared with zoledronic acid. In this study, 368 administrations of denosumab in 219 patients with metastatic bone disease from solid tumors were analyzed to clarify the risk factors for developing hypocalcemia. The results showed that grade 2/3 hypocalcemia was observed in 10.4% of the total number of denosumab administrations. Patients with higher baseline serum ALP, higher performance status (PS), or gastric cancer were at higher risk for developing hypocalcemia. The cut-off value for ALP to predict denosumab-related hypocalcemia was 587 U/L with a sensitivity of 0.77 and a specificity of 0.81. Close monitoring of serum calcium, especially after the first treatment with denosumab, is strongly recommended in these patients.

Detection of inflammatory biomarkers in saliva and urine: Potential in diagnosis, prevention, and treatment for chronic diseases

Inflammation is a part of the complex biological response of inflammatory cells to harmful stimuli, such as pathogens, irritants, or damaged cells. This inflammation has been linked to several chronic diseases including cancer, atherosclerosis, rheumatoid arthritis, and multiple sclerosis. Major biomarkers of inflammation include tumor necrosis factor, interleukins (IL)-1, IL-6, IL-8, chemokines, cyclooxygenase, 5-lipooxygenase, and C-reactive protein, all of which are regulated by the transcription factor nuclear factor-kappaB. Although examining inflammatory biomarkers in blood is a standard practice, its identification in saliva and/or urine is more convenient and non-invasive. In this review, we aim to (1) discuss the detection of these inflammatory biomarkers in urine and saliva; (2) advantages of using salivary and urinary inflammatory biomarkers over blood, while also weighing on the challenges and/or limitations of their use; (3) examine their role(s) in connection with diagnosis, prevention, treatment, and drug development for several chronic diseases with inflammatory consequences, including cancer; and (4) explore the use of innovative salivary and urine based biosensor strategies that may permit the testing of biomarkers quickly, reliably, and cost-effectively, in a decentralized setting.

The best of both worlds - managing the cancer, saving the bone

In the context of breast cancer, the importance of the skeleton in the regulation of primary tumour development and as a site for subsequent metastasis is well characterized. Our understanding of the contributions made by the host bone and bone marrow cells increasingly demonstrates the extent of the interaction between tumour cells and normal host cells. As a result, the need to develop and utilize therapies that can impede the growth and/or function of tumour cells while sparing normal host bone and bone marrow cells is immense and expanding. The need for these new treatments is, however, superimposed on the orthopaedic management of patients' quality of life, where pain control and continued locomotion are paramount. Indeed, the majority of the anticancer therapies used to date often result in direct or indirect damage to bone. Thus, although the bone microenvironment regulates tumour cell growth in bone, cells within the bone marrow niche also mediate many of the orthopaedic consequences of tumour progression as well as resistance to the antitumour effects of existing therapies. In this Review, we highlight the effects of existing cancer treatments on bone and the bone marrow microenvironment as well as the mechanisms mediating these effects and the current utility of modern orthopaedic interventions.

SOST Inhibits Prostate Cancer Invasion

Inhibitors of Wnt signaling have been shown to be involved in prostate cancer (PC) metastasis; however the role of Sclerostin (Sost) has not yet been explored. Here we show that elevated Wnt signaling derived from Sost deficient osteoblasts promotes PC invasion, while rhSOST has an inhibitory effect. In contrast, rhDKK1 promotes PC elongation and filopodia formation, morphological changes characteristic of an invasive phenotype. Furthermore, rhDKK1 was found to activate canonical Wnt signaling in PC3 cells, suggesting that SOST and DKK1 have opposing roles on Wnt signaling in this context. Gene expression analysis of PC3 cells co-cultured with OBs exhibiting varying amounts of Wnt signaling identified CRIM1 as one of the transcripts upregulated under highly invasive conditions. We found CRIM1 overexpression to also promote cell-invasion. These findings suggest that bone-derived Wnt signaling may enhance PC tropism by promoting CRIM1 expression and facilitating cancer cell invasion and adhesion to bone. We concluded that SOST and DKK1 have opposing effects on PC3 cell invasion and that bone-derived Wnt signaling positively contributes to the invasive phenotypes of PC3 cells by activating CRIM1 expression and facilitating PC-OB physical interaction. As such, we investigated the effects of high concentrations of SOST in vivo. We found that PC3-cells overexpressing SOST injected via the tail vein in NSG mice did not readily metastasize, and those injected intrafemorally had significantly reduced osteolysis, suggesting that targeting the molecular bone environment may influence bone metastatic prognosis in clinical settings.

Advanced Oxidation Protein Products as a Novel Marker of Oxidative Stress in Postmenopausal Osteoporosis

BACKGROUND

Advanced oxidation protein products (AOPPs) are acknowledged as a novel marker of oxidation-mediated protein damage. This study aimed to investigate the plasma levels of AOPPs in postmenopausal osteoporotic women, and to determine the relationship between AOPPs accumulation and lumbar bone mineral destiny (BMD) or bone turnover markers.

MATERIAL AND METHODS

Lumbar BMD was measured by dual-energy X-ray absorptiometry. Plasma AOPPs levels as a marker of protein oxidation damage and malondialdehyde (MDA) levels as a marker of lipid peroxidation were measured by spectrophotometry. The concentrations of 2 specific markers of bone turnover, bone-specific alkaline phosphatase (BALP) and tartrate-resistant acid phosphatase5b, (TRACP 5b) were quantified using ELISA kits.

RESULTS

We recruited 60 postmenopausal women meeting osteoporosis (OP) diagnostic criteria of World Health Organization (WHO) and 60 postmenopausal women without OP. Plasma levels of AOPPs (P<0.001), BALP (P<0.001) and TRACP 5b (P<0.001) were statistically significantly increased in the postmenopausal osteoporotic women compared with controls, but there was no statistically significant difference in MDA (P=0.124) between the 2 groups. Plasma AOPPs levels were negatively correlated with lumbar BMD and positively correlated with bone turnover markers both in postmenopausal osteoporotic women and in all subjects. However, plasma MDA levels were not correlated with lumbar BMD or bone turnover markers.

CONCLUSIONS

In postmenopausal osteoporotic women elevated AOPPs is associated with reduced BMD and increased bone turnover markers. Because AOPPs is stable and easy to detect it may be used as a simple plasma marker to predict the severity of postmenopausal OP.

Bone remodeling markers and bone metastases: From cancer research to clinical implications

Bone metastasis is a frequent finding in the natural history of several types of cancers. However, its anticipated risk, diagnosis and response to therapy are still challenging to assess in clinical practice. Markers of bone metabolism are biochemical by-products that provide insight into the tumor-bone interaction, with potential to enhance the clinical management of patients with bone metastases. In fact, these markers had a cornerstone role in the development of bone-targeted agents; however, its translation to routine practice is still unclear, as reflected by current international guidelines. In this review, we aimed to capture several of the research and clinical translational challenges regarding the use of bone metabolism markers that we consider relevant for future research in bone metastasis.

Metastatic tumors to the jaws and mouth

Metastatic dissemination to the oral cavity is rare and is usually the evidence of a wide spread disease with an average survival rate of 7 months. In almost a quarter of the cases, oral metastasis was found to be the first indication of an occult malignancy at a distant site. Metastatic lesions can be found anywhere in the oral cavity, however, the jaw bones with the molar area is the most frequently involved site. In the oral soft tissues, the gingiva is the most common site, suggesting the possible role of inflammation in the attraction of metastatic deposits. The most common primary malignancies presenting oral metastases were the lung, kidney, liver, and prostate for men, and breast, female genital organs, kidney, and colo-rectum for women. Most patients with jawbone metastasis complain of swelling, pain, and paresthesia. An exophytic lesion is the most common clinical presentation of metastatic lesions in the oral soft tissues. Early lesions, mainly those located in the gingiva, may resemble a hyperplastic or reactive lesion. Once a lesion is recognized as metastasis, the primary tumor site should be identified following clinical, radiological and histopathological investigations. If standardized diagnostic workup fails to detect the site of origin, then the term carcinoma of unknown primary is applied. Personalized medicine tools such as tissue-of-origin assays should be applied, either by immunohistochemical testing or by molecular-profiling methods as these may lead to a more favorable outcome.