Classical cannabinoid receptors as target in cancer-induced bone pain: a systematic review, meta-analysis and bioinformatics validation.

To test the hypothesis that genetic and pharmacological modulation of the classical cannabinoid type 1 (CB) and 2 (CB) receptors attenuate cancer-induced bone pain, we searched Medline, Web of Science and Scopus for relevant skeletal and non-skeletal cancer studies from inception to July 28, 2022. We identified 29 animal and 35 human studies. In mice, a meta-analysis of pooled studies showed that treatment of osteolysis-bearing males with the endocannabinoids AEA and 2-AG (mean difference [MD] - 24.

TRAF6 as a potential target in advanced breast cancer: a systematic review, meta-analysis, and bioinformatics validation.

TRAF6 has emerged as a key regulator of breast cancer (BCa). However, the TRAF family constitutes of seven members that exhibit distinct and overlapping functions. To explore which TRAF represents a potential druggable target for BCa treatment, we searched Medline, Web of Science and Scopus for relevant studies from inception to June 27, 2021.

Anti-inflammatory, but not osteoprotective, effect of the TRAF6/CD40 inhibitor 6877002 in rodent models of local and systemic osteolysis.

NFκB plays a key role in inflammation and skeletal disorders. Previously, we reported that pharmacological inhibition of NFκB at the level of TRAF6 suppressed RANKL, CD40L and IL1β-induced osteoclastogenesis and attenuated cancer-induced bone disease. TNFα is also known to regulate TRAF6/NFκB signalling, however the anti-inflammatory and osteoprotective effects associated with inhibition of the TNFα/TRAF6/NFκB axis have not been investigated.

Association of cannabinoid receptor modulation with normal and abnormal skeletal remodelling: A systematic review and meta-analysis of in vitro, in vivo and human studies.

To address the inconsistent findings from studies that used different models to explore the role of classical cannabinoid type 1 (CB1) and 2 (CB2) receptors in skeletal remodelling, we searched Medline, Web of Science and Embase for relevant studies from inception to June 23, 2020. We identified 38 in vitro, 34 in vivo and 9 human studies. A meta-analysis of in vitro studies showed that exposure to the inverse-agonists AM251 (mean difference [MD]:-26.

Combined administration of a small-molecule inhibitor of TRAF6 and Docetaxel reduces breast cancer skeletal metastasis and osteolysis.

Tumour necrosis factor receptor-associated factor 6 (TRAF6) has been implicated in breast cancer and osteoclastic bone destruction. Here, we report that 6877002, a verified small-molecule inhibitor of TRAF6, reduced metastasis, osteolysis and osteoclastogenesis in models of osteotropic human and mouse breast cancer. First, we observed that TRAF6 is highly expressed in osteotropic breast cancer cells and its level of expression was higher in patients with bone metastasis.

JZL184, A Monoacylglycerol Lipase Inhibitor, Induces Bone Loss in a Multiple Myeloma Model of Immunocompetent Mice.

Multiple myeloma (MM) patients develop osteolysis characterised by excessive osteoclastic bone destruction and lack of osteoblast bone formation. Pharmacological manipulation of monoacylglycerol lipase (MAGL), an enzyme responsible for the degradation of the endocannabinoid 2-arachidonoyl glycerol (2-AG), reduced skeletal tumour burden and osteolysis associated with osteosarcoma and advanced breast and prostate cancers. MM and hematopoietic, immune and bone marrow cells express high levels of type 2 cannabinoid receptor and osteoblasts secrete 2-AG.

Paradoxical effects of JZL184, an inhibitor of monoacylglycerol lipase, on bone remodelling in healthy and cancer-bearing mice.

Background: Cancer-associated bone disease is a serious complication in bone sarcomas and metastatic carcinomas of breast and prostate origin. Monoacylglycerol lipase (MAGL) is an enzyme of the endocannabinoid system, and is responsible for the degradation of the most abundant endocannabinoid in bone, 2-arachidonoyl glycerol (2AG).

Methods: The effects of the verified MAGL inhibitor on bone remodelling were assessed in healthy mice and in mouse models of bone disease caused by prostate and breast cancers and osteosarcoma.

Pharmacological Inhibition of NFκB Reduces Prostate Cancer Related Osteoclastogenesis In Vitro and Osteolysis Ex Vivo.

NFκB is implicated in cancer and bone remodelling, and we have recently reported that the verified NFκB inhibitor Parthenolide (PTN) reduced osteolysis and skeletal tumour growth in models of metastatic breast cancer. Here, we took advantage of in vitro and ex vivo bone cell and organ cultures to study the effects of PTN on the ability of prostate cancer cells and their derived factors to regulate bone cell activity and osteolysis. PTN inhibited the in vitro growth of a panel of human, mouse and rat prostate cancer cells in a concentration-dependent manner with a varying degree of potency.

Pharmacological inhibition of the IKKε/TBK-1 axis potentiates the anti-tumour and anti-metastatic effects of Docetaxel in mouse models of breast cancer.

IκB kinase subunit epsilon (IKKε), a key component of NFκB and interferon signalling, has been identified as a breast cancer oncogene. Here we report that the IKKε/TBK1 axis plays a role in the initiation and progression of breast cancer osteolytic metastasis. Cancer-specific knockdown of IKKε in the human MDA-MB-231-BT cells and treatment with the verified IKKε/TBK1 inhibitor Amlexanox reduced skeletal tumour growth and osteolysis in mice.

Raman spectroscopy as a predictive tool for monitoring osteoporosis therapy in a rat model of postmenopausal osteoporosis.

Pharmacological therapy of osteoporosis reduces bone loss and risk of fracture in patients. Modulation of bone mineral density cannot explain all effects. Other aspects of bone quality affecting fragility and ways to monitor them need to be better understood.

Ovariectomy/Orchiectomy in Rodents.

This chapter describes the surgical procedures for ovariectomy and orchiectomy in mice and rats. In addition to providing technical details of the surgical techniques, details of anesthesia options and pre-, peri-, and postoperative care are also included.

Analysis of Signaling Pathways by Western Blotting and Immunoprecipitation.

This chapter describes the analysis of signaling pathways in bone cells by the use of western blotting and immunoprecipitation, including a step-by-step guide to cell culture techniques, cellular and subcellular fractionation, protein isolation, purification, measurement, electrophoretic transfer, and detection.

Bidirectional regulation of bone formation by exogenous and osteosarcoma-derived Sema3A.

Semaphorin 3A (Sema3A), a secreted member of the Semaphorin family, increases osteoblast differentiation, stimulates bone formation and enhances fracture healing. Here, we report a previously unknown role of Sema3A in the regulation of ectopic bone formation and osteolysis related to osteosarcoma. Human recombinant (exogenous) Sema3A promoted the expression of osteoblastic phenotype in a panel of human osteosarcoma cell lines and inhibited the ability of these cells to migrate and enhance osteoclastogenesis in vitro.

Regulation of breast cancer induced bone disease by cancer-specific IKKβ.

NFκB is implicated in breast cancer bone metastasis and skeletal remodelling. However, the role of IKKβ, a key component of the canonical NFκB pathway, in the regulation of breast cancer osteolytic metastasis has not been investigated. Here, we describe the cancer-specific contribution of IKKβ to bone metastasis, skeletal tumour growth and osteolysis associated with breast cancer.

Pharmacological Inhibition of the Skeletal IKKβ Reduces Breast Cancer-Induced Osteolysis.

IKKβ has previously been implicated in breast cancer bone metastasis and bone remodelling. However, the contribution of IKKβ expressed by bone cells of the tumour microenvironment to breast cancer-induced osteolysis has yet to be investigated. Here, we studied the effects of the verified selective IKKβ inhibitors IKKβ or IKKβ on osteoclast formation and osteoblast differentiation in vitro and in vivo, human and mouse breast cancer cells' support for osteoclast formation and signalling in vitro and osteolysis ex vivo and in immunocompetent mice after supracalvarial injection of human MDA-MB-231 conditioned medium or intra-cardiac injection of syngeneic 4T1 breast cancer cells.

TRAF2 in osteotropic breast cancer cells enhances skeletal tumour growth and promotes osteolysis.

NFκB plays an important role in inflammation and bone remodelling. Tumour necrosis factor receptor associated factor 2 (TRAF2), a key component of NFκB signalling, has been identified as an oncogene, but its role in the regulation of breast cancer osteolytic metastasis remains unknown. Here, we report that stable overexpression of TRAF2 in parental and osteotropic sub-clones of human MDA-MB-231 (MDA-231) breast cancer cells increased cell growth and motility in vitro, whereas TRAF2 knockdown was inhibitory.

Raman spectroscopy predicts the link between claw keratin and bone collagen structure in a rodent model of oestrogen deficiency.

Osteoporosis is a common disease characterised by reduced bone mass and an increased risk of fragility fractures. Low bone mineral density is known to significantly increase the risk of osteoporotic fractures, however, the majority of non-traumatic fractures occur in individuals with a bone mineral density too high to be classified as osteoporotic. Therefore, there is an urgent need to investigate aspects of bone health, other than bone mass, that can predict the risk of fracture.

Pharmacological evidence for the bone-autonomous contribution of the NFκB/β-catenin axis to breast cancer related osteolysis.

The NFκB signaling pathway is implicated in breast cancer and bone metastasis. However, the bone-autonomous contribution of NFκB to breast cancer-induced osteolysis is poorly understood. Here, we report that pretreatment of osteoblasts with the sesquiterpene lactone Parthenolide (PTN), a verified NFκB inhibitor, prior to exposure to conditioned medium from human and mouse breast cancer cell lines enhanced osteoblast differentiation and reduced osteoblast ability to stimulate osteoclastogenesis.

Combined deficiency of the Cnr1 and Cnr2 receptors protects against age-related bone loss by osteoclast inhibition.

The endocannabinoid system plays a role in regulating bone mass and bone cell activity and inactivation of the type 1 (Cnr1) or type 2 (Cnr2) cannabinoid receptors influences peak bone mass and age-related bone loss. As the Cnr1 and Cnr2 receptors have limited homology and are activated by different ligands, we have evaluated the effects of combined deficiency of Cnr1 and 2 receptors (Cnr1/2 ) on bone development from birth to old age and studied ovariectomy induced bone loss in female mice. The Cnr1/2 mice had accelerated bone accrual at birth when compared with wild type littermates, and by 3 months of age, they had higher trabecular bone mass.

Emerging therapeutic targets in cancer induced bone disease: A focus on the peripheral type 2 cannabinoid receptor.

Skeletal complications are a common cause of morbidity in patients with primary bone cancer and bone metastases. The type 2 cannabinoid (Cnr2) receptor is implicated in cancer, bone metabolism and pain perception. Emerging data have uncovered the role of Cnr2 in the regulation of tumour-bone cell interactions and suggest that agents that target Cnr2 in the skeleton have potential efficacy in the reduction of skeletal complications associated with cancer.

Bone Cell-autonomous Contribution of Type 2 Cannabinoid Receptor to Breast Cancer-induced Osteolysis.

The cannabinoid type 2 receptor (CB2) has previously been implicated as a regulator of tumor growth, bone remodeling, and bone pain. However, very little is known about the role of the skeletal CB2 receptor in the regulation of osteoblasts and osteoclasts changes associated with breast cancer. Here we found that the CB2-selective agonists HU308 and JWH133 reduced the viability of a variety of parental and bone-tropic human and mouse breast cancer cells at high micromolar concentrations.

Rodent models of osteoporosis.

The aim of this protocol is to provide a detailed description of male and female rodent models of osteoporosis. In addition to indications on the methods of performing the surgical procedures, the choice of reliable and safe anaesthetics is also described. Post-operative care, including analgesia administration for pain management, is also discussed.

Modulation of strain-specific differences in gene expression by cannabinoid type 2 receptor deficiency.

Previous studies have shown that the skeletal consequences of cannabinoid receptor deficiency differ in different strains of mice. In order to explore the mechanisms responsible, we analysed global gene expression in bone from wild-type CD1 mice and littermates with targeted inactivation of the type 2 cannabinoid receptor (Cnr2 (-/-)) and compared the results with those obtained from a similar analysis of wild-type and Cnr2 (-/-) C57BL/6 mice. Trabecular bone volume was increased in Cnr2 (-/-) CD1 mice compared with wild-type littermates but decreased in Cnr2 (-/-) C57BL/6 mice.

Genetic background modifies the effects of type 2 cannabinoid receptor deficiency on bone mass and bone turnover.

Cannabinoid receptors and their ligands play significant roles in regulating bone metabolism. Previous studies of type 1 cannabinoid receptor-deficient mice have shown that genetic background influences the skeletal phenotype. Here, we investigated the effects of genetic background on the skeletal phenotype of mice with type 2 cannabinoid receptor deficiency (Cnr2 (-/-)).