Aromatase inhibitors are widely used in the treatment of hormone-sensitive breast cancer, but their suppression of estrogen production accelerates bone loss, increases fracture risk, and negatively impacts muscle and fat metabolism. Here, we demonstrate that daily low intensity vibration, serving as a non-drug mimetic for exercise, protects musculoskeletal health in skeletally immature, female mice under complete estrogen deprivation. Subsequent improvements in vertebral bone density are paralleled by greater and leaner skeletal muscle mass and function alongside reduced fat accretion and circulating metabolites. In mature, estrogen deprived mice, vibration enhances weekly bisphosphonate treatment, improving bone density, cortical thickness, and mechanical resistance to fracture. These findings support the proposed hypothesis that low intensity vibration reduces musculoskeletal frailty in estrogen deprived mice, with stronger effects observed in younger cohorts, while in skeletally mature mice combination therapy with anti-resorptive treatment is necessary to suppress cancer-treatment induced musculoskeletal degradation.

Background: Turmeric (Curcuma longa L.) rhizomes, whose secondary metabolites include polyphenols and terpenoids, have been used medicinally for millennia. However, modern scientific inquiry has primarily focused on medicinal effects of turmeric’s polyphenolic curcuminoids, including when evaluating turmeric use to maintain bone health. Methods: Disease-specific biological effects of turmeric’s major secondary metabolites (polyphenols and/or terpenoids), with or without associated turmeric rhizome-derived polysaccharides, were determined in vivo using pre-clinical models of clinically relevant resorptive bone diseases induced by different mechanisms. These included inflammatory arthritis, cancer-driven osteolytic bone metastases, and hormone deficiency-driven post-menopausal osteoporosis. Results: In the arthritis model, the safety profile of curcuminoids alone was superior. However, curcuminoids and terpenoids each had anti-inflammatory effects and prevented bone resorption, with polysaccharide-containing curcuminoid extracts having greater effect than curcuminoids alone. In the human osteolytic breast cancer bone metastases model, curcuminoid extracts containing polysaccharides tended to yield greater effects in reducing bone osteolysis and tumor progression than curcuminoids alone or more complex extracts. In contrast, only purified curcuminoids prevented bone loss in a post-menopausal osteoporosis model, while polysaccharide-containing curcuminoid extracts were without effect. In vitro metabolite effects on disease-specific mechanistic pathways in synoviocytes, osteoclasts, or breast cancer cells were consistent with documented in vivo outcomes and included differential metabolite-specific effects. Conclusions: In summary, these findings suggest that turmeric’s potential medicinal musculoskeletal effects are complex, pathway- and target-specific, and not limited to curcuminoids, with safety concerns potentially limiting certain uses.

Acute, high-dose radiation exposure results in life-threatening acute radiation syndrome (ARS) and debilitating delayed effects of acute radiation exposure (DEARE). The DEARE are a set of chronic multi-organ illnesses that can result in early death due to malignancy and other diseases. Animal models have proven essential in understanding the natural history of ARS and DEARE and licensure of medical countermeasures (MCM) according to the FDA Animal Rule. Our lab has developed models of hematopoietic (H)-ARS and DEARE in inbred C57BL/6J and Jackson Diversity Outbred (JDO) mice of both sexes and various ages and have used these models to identify mechanisms of radiation damage and effective MCMs. Herein, aggregate data from studies conducted over decades in our lab, consisting of 3,250 total-body lethally irradiated C57BL/6J young adult mice and 1,188 H-ARS survivors from these studies, along with smaller datasets in C57BL/ 6J pediatric and geriatric mice and JDO mice, were examined for life- span and development of thymic lymphoma in survivors up to 3 years of age. Lifespan was found to be significantly shortened in H-ARS survivors compared to age-matched nonirradiated controls in all four models. Males and females exhibited similar lifespans except in the young adult C57BL/ 6J model where males survived longer than females after 16 months of age. The incidence of thymic lymphoma was increased in H-ARS survivors from the young adult and pediatric C57BL/ 6J models. Consistent with our findings in H-ARS, geriatric mice appeared more radioresistant than other models, with a lifespan and thymic lymphoma incidence more similar to nonirradiated controls than other models. Increased levels of multiple pro- inflammatory cytokines in DEARE bone marrow and serum correlated with shortened lifespan and malignancy, consistent with other animal models and human data. Of interest, G-CSF levels in bone marrow and serum 8-11 months after irradiation were significantly increased in females. Importantly, treatment with granulopoietic cytokine MCM for radiomitigation of H-ARS did not influence the long-term survival rate or incidence of thymic lymphoma in any model. Taken together, these findings indicate that the lifespan of H-ARS survivors was significantly decreased regardless of age at time of exposure or genetic diversity, and was unaffected by earlier treatment with granulopoietic cytokines for radiomitigation of H-ARS.

PDF file - 429K, Supplemental Figure S1: Lymphocytic and neutrophilic inflammation of canine bladder. Supplemental Figure S2: Characterization of K9TCC#2Dakota and UMUC-3 tumors.

Combination treatment of Low-Intensity Vibration (LIV) with zoledronic acid (ZA) was hypothesized to preserve bone mass and muscle strength while reducing adipose tissue accrual associated with complete estrogen (E 2 )-deprivation in young and skeletally mature mice. Complete E 2 -deprivation (surgical-ovariectomy (OVX) and daily injection of aromatase inhibitor (AI) letrozole) were performed on 8-week-old C57BL/6 female mice for 4 weeks following commencement of LIV administration or control (no LIV), for 28 weeks. Additionally, 16-week-old C57BL/6 female E 2 -deprived mice were administered ±LIV twice daily and supplemented with ±ZA (2.5 ng/kg/week). By week 28, lean tissue mass quantified by dual-energy X-ray absorptiometry was increased in younger OVX/AI+LIV(y) mice, with increased myofiber cross-sectional area of quadratus femorii. Grip strength was greater in OVX/AI+LIV(y) mice than OVX/AI(y) mice. Fat mass remained lower in OVX/AI+LIV(y) mice throughout the experiment compared with OVX/AI(y) mice. OVX/AI+LIV(y) mice exhibited increased glucose tolerance and reduced leptin and free fatty acids than OVX/AI(y) mice. Trabecular bone volume fraction and connectivity density increased in the vertebrae of OVX/AI+LIV(y) mice compared to OVX/AI(y) mice; however, this effect was attenuated in the older cohort of E 2 -deprived mice, specifically in OVX/AI+ZA mice, requiring combined LIV with ZA to increase trabecular bone volume and strength. Similar improvements in cortical bone thickness and cross-sectional area of the femoral mid-diaphysis were observed in OVX/AI+LIV+ZA mice, resulting in greater fracture resistance. Our findings demonstrate that the combination of mechanical signals in the form of LIV and anti-resorptive therapy via ZA improve vertebral trabecular bone and femoral cortical bone, increase lean mass, and reduce adiposity in mice undergoing complete E 2 -deprivation. One Sentence Summary: Low-magnitude mechanical signals with zoledronic acid suppressed bone and muscle loss and adiposity in mice undergoing complete estrogen deprivation.Translational Relevance:Postmenopausal patients with estrogen receptor-positive breast cancer treated with aromatase inhibitors to reduce tumor progression experience deleterious effects to bone and muscle subsequently develop muscle weakness, bone fragility, and adipose tissue accrual. Bisphosphonates (i.e., zoledronic acid) prescribed to inhibit osteoclast-mediated bone resorption are effective in preventing bone loss but may not address the non-skeletal effects of muscle weakness and fat accumulation that contribute to patient morbidity. Mechanical signals, typically delivered to the musculoskeletal system during exercise/physical activity, are integral for maintaining bone and muscle health; however, patients undergoing treatments for breast cancer often experience decreased physical activity which further accelerates musculoskeletal degeneration. Low-magnitude mechanical signals, in the form of low-intensity vibrations, generate dynamic loading forces similar to those derived from skeletal muscle contractility. As an adjuvant to existing treatment strategies, low-intensity vibrations may preserve or rescue diminished bone and muscle degraded by breast cancer treatment.

Identification of medical countermeasures (MCM) to mitigate radiation damage and/or protect first responders is a compelling unmet medical need. The prostaglandin E2 (PGE2) analog, 16,16 dimethyl-PGE2 (dmPGE2), has shown efficacy as a radioprotectant and radiomitigator that can enhance hematopoiesis and ameliorate intestinal mucosal cell damage. In this study, we optimized the time of administration of dmPGE2 for protection and mitigation against mortality from the hematopoietic acute radiation syndrome (H-ARS) in young adult mice, evaluated its activity in pediatric and geriatric populations, and investigated potential mechanisms of action. Windows of 30-day survival efficacy for single administration of dmPGE2 were defined as within 3 h prior to and 6–30 h after total-body γ irradiation (TBI). Radioprotective and radio-mitigating efficacy was also observed in 2-year-old geriatric mice and 6-week-old pediatric mice. PGE2 receptor agonist studies suggest that signaling through EP4 is primarily responsible for the radioprotective effects. DmPGE2 administration prior to TBI attenuated the drop in red blood cells and platelets, accelerated recovery of all peripheral blood cell types, and resulted in higher hematopoietic and mesenchymal stem cells in survivor bone marrow. Multiplex analysis of bone marrow cytokines together with RNA sequencing of hematopoietic stem cells indicated a pro-hematopoiesis cytokine milieu induced by dmPGE2, with IL-6 and G-CSF strongly implicated in dmPGE2-mediated radioprotective activity. In summary, we have identified windows of administration for significant radio-mitigation and radioprotection by dmPGE2 in H-ARS, demonstrated survival efficacy in special populations, and gained insight into radioprotective mechanisms, information useful towards development of dmPGE2 as a MCM for first responders, military personnel, and civilians facing radiation threats.

BACKGROUND:Neuropsychiatric symptoms and CSF cytokine, chemokine, and SARS-COV-2 antibody profiles are unknown in pediatric patients with COVID-19 or multisystem inflammatory syndrome (MIS-C), (NP-COVID-19). METHODS:Children at a single pediatric institution quaternary referral center with laboratory-confirmed COVID-19 or MIS-C and neuropsychiatric symptoms were included in this retrospective case series. Clinical symptoms, ancillary testing data, treatments and outcomes are described. Multiplexed electrochemiluminescence assays for cytokines, chemokines and SARS-CoV-2 antibodies were tested in the CSF NP-COVID-19 patients compared to five controls and were analyzed using the Student's t-test. RESULTS:Three of five NP-COVID-19 patients had psychiatric symptoms, and two patients had encephalopathy and seizures. All patients had full or near resolution of neuropsychiatric symptoms by discharge. One patient received intravenous steroids for treatment for psychiatric symptoms; 3/5 other patients received immunotherapy for MIS-C, including IVIG, high-dose steroids, anakinra, and tocilizumab. Pro-inflammatory chemokines, including MIG, MPC, MIP-1β, and TARC were significantly elevated in NP-COVID-19 patients compared to controls. Two of five patients had elevated CSF neurofilament light chain. CSF SARS-CoV-2 antibody titers to the full-length spike, receptor binding domain and N-terminal domain were significantly elevated. SARS-CoV-2 antibody titers strongly correlated with pro-inflammatory chemokines/cytokines, including IL-1β, IL-2, IL-8, TNF-α, and IFN-γ (P≤0.05 for all). CONCLUSIONS:A spectrum of neuropsychiatric clinical manifestations can occur in children with SARS-CoV-2 infection. CSF pro-inflammatory chemokines and SARS-CoV-2 antibodies may serve as biomarkers of SARS-CoV-2 mediated NP-COVID-19. Additional study is required to understand the pathophysiologic mechanisms of neuroinflammation in children with COVID-19 and MIS-C.

SUMMARYZoledronic acid (ZA) prevents muscle weakness in mice with bone metastases; however, its role in muscle weakness in non-tumor-associated metabolic bone diseases and as an effective treatment modality for the prevention of muscle weakness associated with bone disorders, is unknown. We demonstrate the role of ZA-treatment on bone and muscle using a mouse model of accelerated bone remodeling, which represents the clinical manifestation of non-tumor associated metabolic bone disease. ZA increased bone mass and strength and rescued osteocyte lacunocanalicular organization. Short-term ZA treatment increased muscle mass, whereas prolonged, preventive treatment improved muscle mass and function. In these mice, muscle fiber-type shifted from oxidative to glycolytic and ZA restored normal muscle fiber distribution. By blocking TGFβ release from bone, ZA improved muscle function, promoted myoblast differentiation and stabilized Ryanodine Receptor-1 calcium channel. These data demonstrate the beneficial effects of ZA in maintaining bone health and preserving muscle mass and function in a model of metabolic bone disease.Context and significanceTGFβ is a bone regulatory molecule which is stored in bone matrix, released during bone remodeling, and must be maintained at an optimal level for the good health of the bone. Excess TGFβ causes several bone disorders and skeletal muscle weakness. Reducing excess TGFβ release from bone using zoledronic acid in mice not only improved bone volume and strength but also increased muscle mass, and muscle function. Progressive muscle weakness coexists with bone disorders, decreasing quality of life and increasing morbidity and mortality. Currently, there is a critical need for treatments improving muscle mass and function in patients with debilitating weakness. Zoledronic acid’s benefit extends beyond bone and could also be useful in treating muscle weakness associated with bone disorders.

Exercise benefits the musculoskeletal system and reduces the effects of cancer. The effects of exercise are multifactorial, where metabolic changes and tissue adaptation influence outcomes. Mechanical signals, a principal component of exercise, are anabolic to the musculoskeletal system and restrict cancer progression. We examined the mechanisms through which cancer cells sense and respond to low-magnitude mechanical signals introduced in the form of vibration. Low-magnitude, high-frequency vibration was applied to human breast cancer cells in the form of low-intensity vibration（LIV）. LIV decreased matrix invasion and impaired secretion of osteolytic factors PTHLH, IL-11, and RANKL. Furthermore, paracrine signals from mechanically stimulated cancer cells,reduced osteoclast differentiation and resorptive capacity. Disconnecting the nucleus by knockdown of SUN1 and SUN2 impaired LIV-mediated suppression of invasion and osteolytic factor secretion. LIV increased cell stiffness; an effect dependent on the LINC complex. These data show that mechanical vibration reduces the metastatic potential of human breast cancer cells, where the nucleus serves as a mechanosensory apparatus to alter cell structure and intercellular signaling.

Osteoporosis, a condition of skeletal decline that undermines quality of life, is treated with pharmacological interventions that are associated with poor adherence and adverse effects. Complicating efforts to improve clinical outcomes, the incidence of obesity is increasing, predisposing the population to a range of musculoskeletal complications and metabolic disorders. Pharmacological management of obesity has yet to deliver notable reductions in weight and debilitating complications are rarely avoided. By contrast, exercise shows promise as a non-invasive and non-pharmacological method of regulating both osteoporosis and obesity. The principal components of exercise — mechanical signals — promote bone and muscle anabolism while limiting formation and expansion of fat mass. Mechanical regulation of bone and marrow fat might be achieved by regulating functions of differentiated cells in the skeletal tissue while biasing lineage selection of their common progenitors — mesenchymal stem cells. An inverse relationship between adipocyte versus osteoblast fate selection from stem cells is implicated in clinical conditions such as childhood obesity and increased marrow adiposity in type 2 diabetes mellitus, as well as contributing to skeletal frailty. Understanding how exercise-induced mechanical signals can be used to improve bone quality while decreasing fat mass and metabolic dysfunction should lead to new strategies to treat chronic diseases such as osteoporosis and obesity.

Background and Hypothesis: Previously thought to be inert, bone marrow adipose tissue (BMAT) has emerged as a significant fat depot that increases with age, radiation, estrogen deficiency, and high fat diet. Because bone is a preferred site for breast cancer metastasis, the lack of understanding regarding the effects of BMAT accrual on tumor cell migration and proliferation represents a significant knowledge gap in the cancer field. We hypothesized that exposure to adipokines secreted from BMAT-enriched bone marrow would induce changes in the tumor cell transcriptome. Experimental Design or Project Methods: Twenty-week female C57Bl/6 mice were randomized and treated with control diet (5% kcal% fat) or high fat diet (HFD; 60% kcal% fat) for nine weeks. Relative to control mice, HFD mice had increased body weight, peripheral fat mass, BMAT volume, and circulating adipokines. Bone marrow was flushed and cultured for 24 hours, and control or BMAT-enriched conditioned media was collected. The adipokines leptin and MCP-1 were assayed by ELISA and found to be increased in media obtained from BMAT-enriched cultures. Human MDA-MB-231 breast cancer cells were then cultured in bone marrow conditioned media for 24 hours and tumor cells were processed for RNA sequencing.Results: Exposure to soluble factors derived from BMAT-enriched cultures resulted in significant increase in the expression of genes associated with cancer cell motility and neovascularization, including SEMA4C, PLXNA1, and VEGFA. Conclusion and Potential Impact: These data indicate that BMAT contributes to the tumor microenvironment and may drive the progression of breast cancer bone metastases.

Endoxifen, the predominant CYP2D6 metabolite of the selective estrogen receptor modulator (SERM) tamoxifen, is currently being developed as a novel anti-estrogen therapy for the treatment of estrogen receptor (ER)+ breast cancer. Genetic polymorphism of CYP2D6 is a predictor of response to tamoxifen in patients, implicating endoxifen as one of the most active and relevant tamoxifen metabolites. Breast cancer patients treated with adjuvant endocrine therapies including aromatase inhibitors (AIs) and SERMs often report unmanageable musculoskeletal toxicities that can result in treatment discontinuation. While ER binding affinity and anti-tumor effects have been established in preclinical models, the effects of endoxifen on the musculoskeletal system are not fully known. Twenty-week female C57BL/6 mice underwent sham surgery or ovariectomy (OVX) and were treated daily with vehicle, the AI letrozole, or the SERM endoxifen. Body composition was assessed prospectively by DXA. Bone indices and marrow adipose tissue volume were measured by μCT and muscle contractility of the extensor digitorum longus (EDL) was measured ex vivo. After eight weeks, trabecular bone volume fraction (BV/TV) decreased by 50% in OVX-vehicle and OVX-letrozole mice, whereas BV/TV increased threefold in endoxifen mice relative to sham-vehicle. Despite the presence of significantly more trabecular bone following endoxifen treatment, cortical bone analyses revealed impaired periosteal and endosteal expansion of bone, resulting in reduced polar moment of inertia, which is a measure of resistance to fracture. Uterine weight increased significantly in endoxifen-treated mice relative to all OVX groups, similar to what is observed with tamoxifen treatment. Peripheral body fat, bone marrow adipose tissue, and circulating leptin were reduced by endoxifen, suggesting that the drug may elicit positive systemic metabolic effects. At the termination of the study, muscle-specific force was reduced in OVX-endoxifen mice relative to sham-vehicle, OVX-vehicle, and OVX-AI mice, despite no change in muscle mass. While endoxifen shows promise as a potent anti-estrogen therapy for the treatment of ER+ breast cancer, it may be important to monitor patients for endometrial proliferation, morphological changes in bone that increase fracture risk, and for musculoskeletal side effects that could reduce drug compliance. Citation Format: Laura Wright, Khalid Mohammad, Theresa Guise. The anti-estrogen endoxifen altered bone morphology and reduced muscle function in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1808.