The prognostic role of bone turnover markers in multiple myeloma patients: The impact of their assay. A systematic review and meta-analysis

Phenylalanine deprivation inhibits multiple myeloma progression by perturbing endoplasmic reticulum homeostasis

Amino acid metabolic remodeling is a hallmark of cancer, driving an increased nutritional demand for amino acids. Amino acids are pivotal for energetic regulation, biosynthetic support, and homeostatic maintenance to stimulate cancer progression. However, the role of phenylalanine in multiple myeloma (MM) remains unknown. Here, we demonstrate that phenylalanine levels in MM patients are decreased in plasma but elevated in bone marrow (BM) cells. After the treatment, phenylalanine levels increase in plasma and decrease in BM. This suggests that changes in phenylalanine have diagnostic value and that phenylalanine in the BM microenvironment is an essential source of nutrients for MM progression. The requirement for phenylalanine by MM cells exhibits a similar pattern. Inhibiting phenylalanine utilization suppresses MM cell growth and provides a synergistic effect with Bortezomib (BTZ) treatment in vitro and murine models. Mechanistically, phenylalanine deprivation induces excessive endoplasmic reticulum stress and leads to MM cell apoptosis through the ATF3-CHOP-DR5 pathway. Interference with ATF3 significantly affects phenylalanine deprivation therapy. In conclusion, we have identified phenylalanine metabolism as a characteristic feature of MM metabolic remodeling. Phenylalanine is necessary for MM proliferation, and its aberrant demand highlights the importance of low-phenylalanine diets as an adjuvant treatment for MM.

Disrupted radial and tibial microarchitecture in patients with monoclonal gammopathy of undetermined significance

Patients with monoclonal gammopathy of undetermined significance (MGUS) had abnormalities in volumetric BMD (vBMD), microarchitecture, and stiffness at both the radius and tibia by high-resolution peripheral quantitative CT compared to matched controls. This is the first report demonstrating that patients with MGUS have microarchitectural deficits at multiple skeletal sites.

INTRODUCTION

Fracture risk is elevated in patients with monoclonal gammopathy of undetermined significance (MGUS). However, the pathogenesis of bone disease in these patients is poorly understood. Prior work using high-resolution peripheral CT (HRpQCT) demonstrated abnormal microarchitecture at the radius, with predominantly cortical abnormalities. We hypothesized that patients with MGUS have abnormal microarchitecture at both radius and tibia compared to controls, reflecting global skeletal effects of the disease.

METHODS

This case-control study enrolled 36 subjects; patients with MGUS (n = 12) were matched 1:2 by age, sex, and race to controls (n = 24). Areal BMD (aBMD) was measured by DXA, vBMD, and microarchitecture by HRpQCT, and whole bone stiffness by finite element analysis. Serum was drawn for markers of bone metabolism and inflammation.

RESULTS

By DXA, MGUS patients had lower aBMD at the lumbar spine, femoral neck, and 1/3 radius. Markers of bone metabolism and inflammation did not differ. By HRpQCT at the radius, MGUS patients had lower total, trabecular and cortical density, lower trabecular number, and greater trabecular separation and heterogeneity. At the tibia, MGUS patients had lower total and trabecular density, lower trabecular number, greater separation and heterogeneity, and lower whole bone stiffness.

CONCLUSIONS

Patients with MGUS had lower vBMD, cortical, and trabecular abnormalities at the radius compared to matched controls. At the tibia, trabecular abnormalities predominated. These results suggest that in addition to previously described cortical deficits, deterioration of trabecular bone may contribute to a generalized skeletal fragility in patients with MGUS.

A meta-analysis survey of appropriate bone turnover markers in the detection of bone metastasis in lung cancer

BACKGROUND

A number of studies have investigated the clinical significance of bone turnover markers (BTMs) for the diagnosis of bone metastasis (BM) in lung cancer; however, they led to contradictory results. The aim of this meta-analysis was to investigate whether BTMs differ between lung cancer patients with and without BM.

METHODS

Articles were identified by searching Medline, Embase, Web of Science and Scopus. The studies that were identified were pooled and the weighted mean difference (WMD) and its corresponding 95% confidence interval (CI) were calculated. Subgroup analyses and publication bias detection were also conducted.

RESULTS

A final analysis of 1720 subjects (707 patients with BM and 1013 patients without BM) was performed from 16 cohort studies. From the pooled data in the meta-analysis, the total alkaline phosphatase (TALP) (104.35 U/l [95% CI 33.36-175.34]), bone-specific ALP (BALP) (13.24 μg/l [95% CI 8.50-17.98] or 6.84 U/l [95% CI 2.98-10.70]), C-terminal cross-linked telopeptide of type I collagen (ICTP) (5.07 μg/l [95% CI 3.58-6.56]) and N-terminal cross-linked telopeptide of type I collagen (NTX) (5.08 nM bone collagen equivalent/l [95% CI 2.82-7.33]) were significantly lower among BM patients than non-BM patients. Subgroup analyses detected that the serum level of tartrate-resistant acid phosphatase isoform 5b was significantly reduced in Caucasian patients with BM (-0.64 U/l [95% CI -1.02 to -0.25]), while increased in Asian patients with BM (2.69 U/l [95% CI 0.08-5.31]), compared to patients without BM.

CONCLUSIONS

The present meta-analysis suggested that serum measurement of TALP, BALP, ICTP and NTX might be helpful in detecting BM in lung cancer.

Molecular mechanisms, current management and next generation therapy in myeloma bone disease

Multiple myeloma (MM) bone disease is a major cause of morbidity and mortality in MM patients and persists even in patients in remission. This bone disease is caused by an uncoupling of bone remodeling, with increased osteoclast and decreased osteoblast activity and formation, culminating in lytic bone destruction. Bisphosphonates are the current standard of care but new therapies are needed. As the molecular mechanisms controlling MM bone disease are increasingly well understood, new therapeutic targets are extensively explored in the preclinical setting and initial clinical trials with novel compounds now show promising results. In this review, we will provide a comprehensive overview of the biology of MM bone disease, summarize its current clinical management and discuss preclinical and clinical data on next generation therapies.

Radiological features of experimental staphylococcal septic arthritis by micro computed tomography scan

BACKGROUND

Permanent joint dysfunction due to bone destruction occurs in up to 50% of patients with septic arthritis. Recently, imaging technologies such as micro computed tomography (μCT) scan have been widely used for preclinical models of autoimmune joint disorders. However, the radiological features of septic arthritis in mice are still largely unknown.

METHODS

NMRI mice were intravenously or intra-articularly inoculated with S. aureus Newman or LS-1 strain. The radiological and clinical signs of septic arthritis were followed for 10 days using μCT. We assessed the correlations between joint radiological changes and clinical signs, histological changes, and serum levels of cytokines.

RESULTS

On days 5-7 after intravenous infection, bone destruction verified by μCT became evident in most of the infected joints. Radiological signs of bone destruction were dependent on the bacterial dose. The site most commonly affected by septic arthritis was the distal femur in knees. The bone destruction detected by μCT was positively correlated with histological changes in both local and hematogenous septic arthritis. The serum levels of IL-6 were significantly correlated with the severity of joint destruction.

CONCLUSION

μCT is a sensitive method for monitoring disease progression and determining the severity of bone destruction in a mouse model of septic arthritis. IL-6 may be used as a biomarker for bone destruction in septic arthritis.