Progression of breast cancer to metastatic bone disease is linked to deregulated expression of the transcription factor Runx2. Therefore, our goal was to evaluate the potential for clinical use of ...Runx2-targeting miRNAs to reduce tumor growth and bone metastatic burden. Expression analysis of a panel of miRNAs regulating Runx2 revealed a reciprocal relationship between the abundance of Runx2 protein and two miRNAs, miR-135 and miR-203. These miRNAs are highly expressed in normal breast epithelial cells where Runx2 is not detected, and absent in metastatic breast cancer cells and tissue biopsies that express Runx2. Reconstituting metastatic MDA-MB-231-luc cells with miR-135 and miR-203 reduced the abundance of Runx2 and expression of the metastasis-promoting Runx2 target genes IL11, MMP-13, and PTHrP. In addition, tumor cell viability was decreased and migration suppressed in vitro. Orthotopic implantation of MDA-MB-231-luc cells delivered with miR-135 or miR-203, followed by an intratumoral administration of the synthetic miRNAs, reduced the tumor growth and spontaneous metastasis to bone. Furthermore, intratibial injection of these miRNA-delivered cells impaired tumor growth in the bone environment and inhibited bone resorption. Importantly, reconstitution of Runx2 in MDA-MB-231-luc cells delivered with miR-135 and miR-203 reversed the inhibitory effect of the miRNAs on tumor growth and metastasis. Thus, we have identified that aberrant expression of Runx2 in aggressive tumor cells is related to the loss of specific Runx2-targeting miRNAs and that a clinically relevant replacement strategy by delivery of synthetic miRNAs is a candidate for a therapeutic approach to prevent metastatic bone disease by this route.
Summary Chondrogenic dwarfism in Morquio disease (mucopolysaccharidosis IV) has been suggested to be strongly linked to the abnormal lysosomal storage of cartilaginous extracellular matrix waste ...products within chondrocytes and fibroblasts. The specific genetic defects of enzymes of the keratan sulfate and chondroitin-6-sulfate metabolism have been detected at the molecular level and importantly contributed to the current knowledge on the phenotype of this rare metabolic disorder. However, the pathogenesis of this epiphyseal centered progressive skeletal disease does not seem to be fully explained by the dysfunction of the chondrocyte cytoplasm that presents with vacuolar changes in adult patients. I propose that the accumulation of extracellular matrix degradation product-laden macrophages within epiphyseal cartilage canals during the early postnatal period causes dysregulation in the synchronized process of the neoformation and resorption of the maturing radial growing epiphyses. Similarly, the resorption of pannus tissue following the microtraumatisation of weight-bearing joints and epiphysis-type bones becomes impacted. If the hypothesis is valid, the early pathogenesis in Morquio disease could be because of the inadequate regression of cartilage canals and impaired resorption and restitution of pannus tissue.
The differentiation and degree of the effects of mineral content and/or morphology on bone quality remain, to a large extent, unanswered due to several microarchitectural particularities in spatial ...measuring fields (e.g., force transfer, trajectories, microcalli). Therefore, as the smallest basic component of cancellous bone, we focused on single trabeculae to investigate the effects of mineralization and structure, both independently and in superposition. Transiliac Bordier bone cores and T12 vertebrae were obtained from 20 females at autopsy for specimen preparation, enabling radiographical analyses, histomorphometry, Bone Mineral Density Distribution (BMDD) analyses, and trabecular singularization to be performed. Evaluated contact X-rays and histomorphometric limits from cases with osteoporotic vertebral fractures generated two subdivisions, osteoporotic (n=12, Ø 78 years) and non-osteoporotic (n=8, Ø 49 years) cases, based on fracture appearance and bone volume (BV/TV). Measurements of trabecular number (Tb.N.), trabecular separation (Tb.Sp.), trabecular thickness (Tb.Th.), trabecular bone pattern factor (TBPf) and eroded surface (ES/BS) were carried out to provide detailed structural properties of the investigated groups. The mechanical properties of 400 rod-like single vertebral trabeculae, assessed by three-point bending, were matched with mineral properties as quantified by BMDD analyses of cross-sectioned rod-like and plate-like trabeculae, both in superposition and independently. Non-osteoporotic iliac crests and vertebrae displayed linear dependency on structure parameters, whereas osteoporotic compartments proved to be non-correlated with bone structure. Independent of trabecular thickness, osteoporotic rod-like trabeculae showed decreases in Young's modulus, fracture load, yield strength, ultimate stress, work to failure and bending stiffness, along with significantly increased mean calcium content and calcium width. Non-osteoporotic trabeculae showed biomechanically beneficial properties due to a homogeneous mineralization configuration, whereas osteoporotic trabeculae predominantly demonstrated various mineralized bone packets, eroded surfaces, highly mineralized cement lines and microcracks. The Young's moduli of single trabeculae exhibited significantly negative linear correlations with trabecular thickness. Because of increased, but inhomogeneously distributed, calcium content, osteoporotic trabeculae may be subject to shear stresses that render bone fragile beyond structure impairment due to cracks and lacunae.
It is widely accepted that the subchondral bone (SCB) plays a crucial role in the physiopathology of osteoarthritis (OA), although its contribution is still debated. Much of the pre-clinical research ...on the role of SCB is concentrated on comparative evaluations of healthy vs. early OA or early OA vs. advanced OA cases, while neglecting how pure maturation could change the SCB's microstructure. To assess the transformations of the healthy SCB from young age to early adulthood, we examined the microstructure and material composition of the medial condyle of the femur in calves (three months) and cattle (18 months) for the calcified cartilage (CC) and the subchondral bone plate (SCBP). The entire subchondral zone (SCZ) was significantly thicker in cattle compared to calves, although the proportion of the CC and SCBP thicknesses were relatively constant. The trabecular number (Tb.N.) and the connectivity density (Conn.D) were significantly higher in the deeper region of the SCZ, while the bone volume fraction (BV/TV), and the degree of anisotropy (DA) were more affected by age rather than the region. The mineralization increased within the first 250 µm of the SCZ irrespective of sample type, and became stable thereafter. Cattle exhibited higher mineralization than calves at all depths, with a mean Ca/P ratio of 1.59 and 1.64 for calves and cattle, respectively. Collectively, these results indicate that the SCZ is highly dynamic at early age, and CC is the most dynamic layer of the SCZ.
Osteosarcoma (OS) is a primary bone tumor that is most prevalent during adolescence. RUNX2, which stimulates differentiation and suppresses proliferation of osteoblasts, is deregulated in OS. Here, ...we define pathological roles of RUNX2 in the etiology of OS and mechanisms by which RUNX2 expression is stimulated. RUNX2 is often highly expressed in human OS biopsies and cell lines. Small interference RNA-mediated depletion of RUNX2 inhibits growth of U2OS OS cells. RUNX2 levels are inversely linked to loss of p53 (which predisposes to OS) in distinct OS cell lines and osteoblasts. RUNX2 protein levels decrease upon stabilization of p53 with the MDM2 inhibitor Nutlin-3. Elevated RUNX2 protein expression is post-transcriptionally regulated and directly linked to diminished expression of several validated RUNX2 targeting microRNAs in human OS cells compared with mesenchymal progenitor cells. The p53-dependent miR-34c is the most significantly down-regulated RUNX2 targeting microRNAs in OS. Exogenous supplementation of miR-34c markedly decreases RUNX2 protein levels, whereas 3′-UTR reporter assays establish RUNX2 as a direct target of miR-34c in OS cells. Importantly, Nutlin-3-mediated stabilization of p53 increases expression of miR-34c and decreases RUNX2. Thus, a novel p53-miR-34c-RUNX2 network controls cell growth of osseous cells and is compromised in OS.
Background: Osteosarcoma (OS) is associated with loss of tumor suppressor p53 and increased Runx2.
Results: Runx2 and p53 levels are inversely correlated in OS. miR-34c, which targets Runx2, is absent in OS and elevated by p53.
Conclusion: p53, miR-34c, and Runx2 form a regulatory loop that is compromised in OS.
Significance: RUNX2 could be targeted by miR-34c to prevent OS growth.
Successful treatment of acute radiation syndromes relies on immediate supportive care. In patients with limited hematopoietic recovery potential, hematopoietic stem cell (HSC) transplantation is the ...only curative treatment option. Because of time consuming donor search and uncertain outcome we propose MSC treatment as an alternative treatment for severely radiation-affected individuals.
Mouse mesenchymal stromal cells (mMSCs) were expanded from bone marrow, retrovirally labeled with eGFP (bulk cultures) and cloned. Bulk and five selected clonal mMSCs populations were characterized in vitro for their multilineage differentiation potential and phenotype showing no contamination with hematopoietic cells. Lethally irradiated recipients were i.v. transplanted with bulk or clonal mMSCs. We found a long-term survival of recipients with fast hematopoietic recovery after the transplantation of MSCs exclusively without support by HSCs. Quantitative PCR based chimerism analysis detected eGFP-positive donor cells in peripheral blood immediately after injection and in lungs within 24 hours. However, no donor cells in any investigated tissue remained long-term. Despite the rapidly disappearing donor cells, microarray and quantitative RT-PCR gene expression analysis in the bone marrow of MSC-transplanted animals displayed enhanced regenerative features characterized by (i) decreased proinflammatory, ECM formation and adhesion properties and (ii) boosted anti-inflammation, detoxification, cell cycle and anti-oxidative stress control as compared to HSC-transplanted animals.
Our data revealed that systemically administered MSCs provoke a protective mechanism counteracting the inflammatory events and also supporting detoxification and stress management after radiation exposure. Further our results suggest that MSCs, their release of trophic factors and their HSC-niche modulating activity rescue endogenous hematopoiesis thereby serving as fast and effective first-line treatment to combat radiation-induced hematopoietic failure.
Activation of osteoclasts and their acidification-dependent resorption of bone is thought to maintain proper serum calcium levels. Here we show that osteoclast dysfunction alone does not generally ...affect calcium homeostasis. Indeed, mice deficient in Src, encoding a tyrosine kinase critical for osteoclast activity, show signs of osteopetrosis, but without hypocalcemia or defects in bone mineralization. Mice deficient in Cckbr, encoding a gastrin receptor that affects acid secretion by parietal cells, have the expected defects in gastric acidification but also secondary hyperparathyroidism and osteoporosis and modest hypocalcemia. These results suggest that alterations in calcium homeostasis can be driven by defects in gastric acidification, especially given that calcium gluconate supplementation fully rescues the phenotype of the Cckbr-mutant mice. Finally, mice deficient in Tcirg1, encoding a subunit of the vacuolar proton pump specifically expressed in both osteoclasts and parietal cells, show hypocalcemia and osteopetrorickets. Although neither Src- nor Cckbr-deficient mice have this latter phenotype, the combined deficiency of both genes results in osteopetrorickets. Thus, we find that osteopetrosis and osteopetrorickets are distinct phenotypes, depending on the site or sites of defective acidification.
Paget's Disease of Bone: Histologic Analysis of 754 Patients Seitz, Sebastian; Priemel, Matthias; Zustin, Jozef ...
Journal of bone and mineral research,
January 2009, 2009, 2009-Jan, 2009-01-01, 20090101, Letnik:
24, Številka:
1
Journal Article
Recenzirano
Although Paget's disease of bone (PDB) is the second most common metabolic bone disease, to our knowledge, there is only one quantitative analysis on the histological and especially on the ...histomorphometric level. Therefore, the aim of this study was to analyze, on the basis of the Hamburg Bone Register, PBD in terms of incidence, skeletal distribution, malignant transformation, and histological and histomorphometric characteristics. Bone biopsies and patient files of 754 cases with histologically proven PDB were reviewed in a retrospective study. Quantitative static histomorphometry was performed on a representative subgroup of 247 biopsies derived from patients with manifestation of PDB at the iliac crest and compared with an age‐ and sex‐matched control group. The peak incidence of PDB was between 70 and 80 yr of age. The majority of monostotic skeletal manifestation was localized at the os ilium, followed by the spine and femur. Histomorphometric results showed a high bone turnover with a significant increase in bone resorption and bone formation indices leading to an increased bone volume. Paget sarcoma was diagnosed in 6 of 754 patients, indicating a malignant transformation in 0.8% of the affected patients. Taken together, our study characterizes PDB in Germany on the basis of one of the largest cohorts of patients with histologically proven PDB. Moreover, for the first time, a quantitative histomorphometric approach was taken for >200 cases, where we could show local high bone mass lesions as a result of an increase of both osteoclast and osteoblast indices.
Mucopolysaccharidosis IVA (MPS IVA; Morquio A syndrome) is a lysosomal storage disorder caused by deficiency of N-acetylgalactosamine-6-sulfate sulfatase, which results in systemic accumulation of ...glycosaminoglycans (GAGs), keratan sulfate and chondroitin-6-sulfate. Accumulation of these GAGs causes characteristic features as disproportionate dwarfism associated with skeletal deformities, genu valgum, pigeon chest, joint laxity, and kyphoscoliosis. However, the pathological mechanism of systemic skeletal dysplasia and involvement of other tissues remain unanswered in the paucity of availability of an autopsied case and successive systemic analyses of multiple tissues.
We report here a 20-year-old male autopsied case with MPS IVA, who developed characteristic skeletal features by the age of 1.5years and died of acute respiratory distress syndrome five days later after occipito-C1–C2 cervical fusion. We pathohistologically analyzed postmortem tissues including trachea, lung, thyroid, humerus, aorta, heart, liver, spleen, kidney, testes, bone marrow, and lumbar vertebrae.
The postmortem tissues relevant with clinical findings demonstrated 1) systemic storage materials in multiple tissues beyond cartilage, 2) severely vacuolated and ballooned chondrocytes in trachea, humerus, vertebrae, and thyroid cartilage with disorganized extracellular matrix and poor ossification, 3) appearance of foam cells and macrophages in lung, aorta, heart valves, heart muscle, trachea, visceral organs, and bone marrow, and 4) storage of chondrotin-6-sulfate in aorta.
This is the first autopsied case with MPS IVA whose multiple tissues have been analyzed pathohistologically and these pathological findings should provide a new insight into pathogenesis of MPS IVA.
Radiotherapy (RT) is a standard treatment for patients with advanced prostate cancer (PCa). Previous preclinical studies showed that SDF1α/CXCR4 axis could mediate PCa metastasis (most often to the ...bones) and cancer resistance to RT. We found high levels of expression for both SDF1α and its receptor CXCR4 in primary and metastatic PCa tissue samples. In vitro analyses using PCa cells revealed an important role of CXCR4 in cell invasion but not radiotolerance. Pharmacologic inhibition of CXCR4 using AMD3100 showed no efficacy in orthotopic primary and bone metastatic PCa models. However, when combined with RT, AMD3100 potentiated the effect of local single-dose RT (12 Gy) in both models. Moreover, CXCR4 inhibition also reduced lymph node metastasis from primary PCa. Notably, CXCR4 inhibition promoted the normalization of bone metastatic PCa vasculature and reduced tissue hypoxia. In conclusion, the SDF1α/CXCR4 axis is a potential therapeutic target in metastatic PCa patients treated with RT.
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