Osteoporosis and cancer

Acute myeloid leukemia transforms the bone marrow niche into a leukemia-permissive microenvironment through exosome secretion

Little is known about how leukemia cells alter the bone marrow (BM) niche to facilitate their own growth and evade chemotherapy. Here, we provide evidence that acute myeloid leukemia (AML) blasts remodel the BM niche into a leukemia growth-permissive and normal hematopoiesis-suppressive microenvironment through exosome secretion. Either engrafted AML cells or AML-derived exosomes increased mesenchymal stromal progenitors and blocked osteolineage development and bone formation in vivo. Preconditioning with AML-derived exosomes ‘primed’ the animals for accelerated AML growth. Conversely, disruption of exosome secretion in AML cells through targeting Rab27a, an important regulator involved in exosome release, significantly delayed leukemia development. In BM stromal cells, AML-derived exosomes induced the expression of DKK1, a suppressor of normal hematopoiesis and osteogenesis, thereby contributing to osteoblast loss. Conversely, treatment with a DKK1 inhibitor delayed AML progression and prolonged survival in AML-engrafted mice. In addition, AML-derived exosomes induced a broad downregulation of hematopoietic stem cell-supporting factors (for example, CXCL12, KITL and IGF1) in BM stromal cells and reduced their ability to support normal hematopoiesis. Altogether, this study uncovers novel features of AML pathogenesis and unveils how AML cells create a self-strengthening leukemic niche that promotes leukemic cell proliferation and survival, while suppressing normal hematopoiesis through exosome secretion.

Falls in older adults with cancer: a systematic review of prevalence, injurious falls, and impact on cancer treatment

PURPOSE

The purpose of this systematic review was to update and expand the existing systematic review with the aim to answer the following questions: (1) How often do older adults (OA)s with cancer fall? (2) What are the predictors of falls in OA with cancer? (3) What is the rate of injurious falls and predictors of injurious falls in OA with cancer? (4) What are the circumstances and outcomes of falls in this population? (5) How do falls in cancer patients affect subsequent cancer treatment?

METHODS

Medline, Pubmed, Embase, and CINAHL were searched. Eligible studies included clinical trials, cross-sectional, cohort, case-control, and qualitative studies in which the entire sample or a sub-group of the sample were OA aged 60 and above, had cancer, in which falls were examined as a primary or secondary outcome and published in English.

RESULTS

Twenty-seven studies met our inclusion criteria with most involving the outpatient setting. Fall rates and injurious fall rates varied widely. Consistent predictors of falls were prior falls among outpatients and cognitive impairment among inpatients. There were no data on impact of falls on cancer treatment. Data on circumstances of falls were limited.

CONCLUSION

Falls and fall-related injuries are common in older cancer patients. However, little is known about circumstances of falls and impact of falls on cancer treatment. Many known fall predictors in community-dwelling OA have not been explored in oncology. More research is needed to address gaps in these areas.

ZIP4 silencing improves bone loss in pancreatic cancer

Metabolic bone disorders are associated with several types of human cancers. Pancreatic cancer patients usually suffer from severe nutrition deficiency, muscle wasting, and loss of bone mass. We have previously found that silencing of a zinc transporter ZIP4 prolongs the survival and reduces the severity of the cachexia in vivo. However, the role of ZIP4 in the pancreatic cancer related bone loss remains unknown. In this study we investigated the effect of ZIP4 knockdown on the bone structure, composition and mechanical properties of femurs in an orthotopic xenograft mouse model. Our data showed that silencing of ZIP4 resulted in increased bone tissue mineral density, decreased bone crystallinity and restoration of bone strength through the RANK/RANKL pathway. The results further support the impact of ZIP4 on the progression of pancreatic cancer, and suggest its potential significance as a therapeutic target for treating patients with such devastating disease and cancer related disorders.

Investigation of Vitamin D-Binding Protein Polymorphism Impact on Coronary Artery Disease and Relationship with Longevity: Own Data and a Review

The aim of the study was to assess the effect of vitamin D-binding protein (DBP) polymorphism on coronary artery disease (CAD). DBP phenotypes were identified in the groups: control (n = 306), men suffering from CAD (n = 154), and long-lived individuals (n = 108). Isoelectric focusing of DBP phenotypes in serum was performed on polyacrylamide gel. Distribution of DBP phenotypes in the study groups was found to be in Hardy-Weinberg equilibrium. Gc1s-1s phenotype and Gc1s allele frequency in CAD groups were significantly higher than in control, and Gc1s allele frequency was found significantly more often in CAD compared with long-lived group (p < 0.05). The Gc2 allele frequency in control was higher as compared with Gc2 frequency in CAD group (p < 0.05). The Gc2-2 phenotype was more frequent in long-lived survivors than in the CAD group (p < 0.05). It was found that the Gc1s allele significantly increased the risk of CAD with the odds ratio (OR) equal to 1.45 (p < 0.02) and showed Gc2 to be related with a decreased risk of CAD (OR = 0.69; p < 0.03). Authors review the role of DBP in resistance to atherosclerosis and cancer as the main longevity determinants.

Geriatric assessment as an aide to understanding falls in older adults with cancer

PURPOSE

In older adults, falls are a common cause of functional decline, institutionalization, and reduced quality of life. This study (1) investigates the prevalence of falls in a large sample of community-dwelling older adults with a cancer diagnosis and (2) evaluates the association of falls with domains of comprehensive geriatric assessment (CGA) that pertain to falls risk.

METHODS

Patients completed a CGA that includes a self-reported measure of number of falls in the past 6 months. Summary statistics are used to describe prevalence of falls and associations with hypothesized risk factors using Fisher's exact tests and multivariable logistic regression.

RESULTS

A total of 1172 patients were enrolled, mean age 73 (65-99), 74 % female, and 89 % Caucasian. Two hundred fifty-six (22 %) reported one or more falls within the last 6 months. Patients with at least one instrumental activities of daily living (IADL) or physical function deficit had more falls as compared those with no deficits identified (p ≤ 0.001). The number of daily medications, comorbidities, Timed Up and Go score >14 s, and poor vision were also associated with increased falls (p ≤ 0.001). Reduced physical function, poor vision, and low performance status had the highest adjusted odds ratio (3.6, 3.4, and 3.0, respectively) for falls.

CONCLUSIONS

There is a high prevalence of falls in community-dwelling older patients with a cancer diagnosis. Falls are significantly associated with several measures of geriatric assessment including IADL, physical function, comorbidities, medications, and vision. Timely identification and management of risk factors for falls are important considerations in the care of older cancer patients.

unveiling skeletal fragility in patients diagnosed with MGUS: no longer a condition of undetermined significance?

Monoclonal gammopathy of undetermined significance (MGUS) is a common finding in clinical practice, affecting greater than 3% of adults aged 50 years and older. As originally described, the term MGUS reflected the inherent clinical uncertainty of distinguishing patients with a benign stable monoclonal plasma cell disorder from subjects destined to progress to malignancy. There is now clear epidemiologic evidence, however, that patients with MGUS suffer from a significantly increased fracture risk and that the prevalence of MGUS is increased in patients with osteoporosis. Despite this relationship, no clinical care guidelines exist for the routine evaluation or treatment of the skeletal health of patients with MGUS. Recent work has demonstrated that circulating levels of at least two cytokines (CCL3/MIP-1α and DKK1) with well-recognized roles in bone disease in the related monoclonal gammopathy multiple myeloma are also increased in patients with MGUS. Further, recent imaging studies using high-resolution peripheral quantitative CT have documented that patients with MGUS have substantial skeletal microarchitectural deterioration and deficits in biomechanical bone strength that likely underlie the increased skeletal fragility in these patients. Accordingly, this Perspective provides evidence that the "undetermined significance" portion of the MGUS acronym may be best replaced in favor of the term "monoclonal gammopathy of skeletal significance" (MGSS) in order to more accurately reflect the enhanced skeletal risks inherent in this condition.