Curcumin reduces trabecular and cortical bone in naive and lewis lung carcinoma-bearing mice.

The present study investigated the effects of curcumin on bone microstructure in non-tumor-bearing and Lewis lung carcinoma-(LLC)-bearing female C57BL/6 mice. Morphometric analysis showed that dietary supplementation with curcumin (2% or 4%) significantly reduced the bone volume to total volume ratio, connectivity density and trabecular number, and significantly increased the structure model index (an indicator of the plate- and rod-like geometry of trabecular structure) and trabecular separation in vertebral bodies compared to controls in both non-tumor-bearing and LLC-bearing mice. Similar changes in trabecular bone were observed in the femoral bone in curcumin-fed mice. Curcumin significantly reduced the cortical bone area to total area ratio and cortical thickness in femoral mid-shaft, but not in vertebral bodies, in both non-tumor-bearing and LLC-bearing mice. Curcumin feeding reduced plasma concentrations of osteocalcin and increased tartrate-resistant acid phosphate 5b in mice regardless of the presence of LLC, indicating that curcumin disrupts the balance of bone remodeling. Our results demonstrated that curcumin reduced the trabecular bone volume and cortical bone density. The skeleton is a favored site of metastasis for many types of cancers, and curcumin has been investigated in clinical trials in patients with cancer for its chemopreventive effects. Our results suggest the possibility of a combined effect of cancer-induced osteolysis and curcumin-stimulated bone loss in patients using curcumin. The assessment of bone structural changes should be considered for those who participate in curcumin clinical trials to determine its effects on skeleton health, particularly for those with advanced malignancies.

Continuous and intermittent exposure of neonatal rat calvarial cells to PTHrP (1-36) inhibits bone nodule mineralization in vitro by downregulating bone sialoprotein expression via the cAMP signaling pathway.

The development and growth of the skeleton in the absence of parathyroid-hormone-related protein (PTHrP) is abnormal.  The shortening of appendicular bones in PTHrP gene null mice is explained by an effect of PTHrP on endochondral bone growth.  Whether or not PTHrP influences intramembranous ossification is less clear.  The purpose of this study was to determine the effect of exogenous PTHrP on intramembranous ossification in vitro.  Neonatal rat calvarial cells maintained in primary cell culture conditions that permit spontaneous formation of woven bone nodules by intramembranous ossification were studied. The expression of PTHrP, parathyroid hormone 1 receptor (PTH1R), and alkaline phosphatase (AP) by osteogenic cells in developing nodules and the effects of PTHrP (1-36) on nodule development was determined over 3-18 days. PTHrP and PTH1R were detected colonies of osteogenic cells on culture day three, and AP was detected on day six. PTHrP and its receptor were localized in pre-osteoblasts, osteoblasts, and osteocytes, and AP activity was detected in pre-osteoblasts and osteoblasts but not osteocytes. Continuous and intermittent exposure to PTHrP (1-36) decreased the number of mineralized bone nodules and bone sialoprotein (BSP) mRNA and protein, but had no effect on the number of AP-positive osteogenic cell colonies, cell proliferation, apoptosis, or osteopontin (OPN) mRNA. These results demonstrate that osteogenic cells that participate in the formation of woven bone nodules in vitro exhibit PTHrP and PTH1R before they demonstrate AP activity. Exogenous PTHrP (1-36) inhibits the mineralization of woven bone deposited during bone nodule formation in vitro, possibly by reducing the expression of BSP.

Biphasic effects of interleukin-1beta on osteoblast differentiation in vitro.

A rat calvarial cell model of osteoblast differentiation using the formation of bone nodules in vitro as an endpoint was used to assess the effects of IL-1beta on osteoblast differentiation. Short-term treatment (2 days) with IL-1beta early in culture resulted in increased nodule number and size as well as calcium content in contrast to long-term treatment (6 days) in cultures assessed at 10-12 days. This increase in bone formation was blocked by IL-1 receptor antagonists. Short-term treatment increased COX-2, prostaglandin (PGE(2)), and iNOS production. Exogenous PGE(2) with IL-1beta enhanced this effect. COX-2 inhibitors, indomethacin and N-39, blocked 50% of nodule formation. NO donor did not modify effects of IL-1beta, but iNOS inhibitor (1400W) partially blocked the effects. However, PGE(2) and NO donors could not rescue the decreased nodule number resulting from long-term IL-1beta treatment. The results of this study suggest a biphasic effect of IL-1beta on bone nodule formation activated by IL-1beta binding with IL-1 receptors, and the anabolic effect of early short-term treatment with IL-1beta is likely mediated by PGE without ruling out nitric oxide.

Dietary supplementation with high-selenium soy protein reduces pulmonary metastasis of melanoma cells in mice.

The effect of high-selenium (Se) soy protein on pulmonary metastasis of murine B16BL6 melanoma cells was investigated in male C57BL6 mice. Isolated soy proteins (ISP) from soybeans grown with and without Se foliar application during seed development were compared. Five diets were studied, a basal AIN-93G diet or a basal diet containing 10% low-Se ISP, 5% low-Se + 5% high-Se ISP, 10% high-Se ISP, or 10% low-Se ISP supplemented with Se equivalent to that of the 10% high-Se ISP diet. The Se concentrations of the 5 diets were 0.13, 0.13, 1.9, 3.6, and 3.0 microg/g, respectively. Mice were fed the diet for 2 wk before and 2 wk after an i.v. injection of 5 x 10(4) viable cells. At necropsy, the number and size of tumors that had developed in the lungs were determined. In the control group, 13/18 mice exhibited > or = 50 tumors. The numbers of mice with > or = 50 tumors were 8/18, 7/18, 3/18, and 6/17 in the ISP-fed groups, respectively. The differences between the 10% high-Se ISP group, the Se-supplemented 10% low-Se group, and the control were significant (P < 0.05). Dietary supplementation with 10% low-Se ISP significantly decreased the mean number of tumors per group and the tumor size compared with the control. A greater reduction in these variables occurred in mice fed the 10% high-Se ISP diet. The inhibition by the Se-supplemented 10% low-Se ISP diet was similar to that by the 10% high-Se ISP diet. The whole-blood Se concentration was inversely related to the tumor number (R = -0.87, P = 0.052), tumor cross-sectional area (R = -0.91, P < 0.05), and tumor volume (R = -0.93, P < 0.05). These findings suggest that Se is responsible for the greater antimetastatic effect of the high-Se ISP. We conclude that the high-Se soy protein has a greater inhibitory effect than the low-Se soy protein on pulmonary metastasis of melanoma cells in mice.

Dietary supplementation with isolated soy protein reduces metastasis of mammary carcinoma cells in mice.

The present study investigated the effect of dietary supplementation with isolated soy protein (ISP) on pulmonary metastasis of carcinoma cells from primary mammary tumors induced by orthotopic injection of 4526 murine mammary carcinoma cells in female BALB/c mice. Three diets were compared: a basal AIN-93G diet and the basal diet supplemented with 10% or 20% ISP. After three weeks on the experimental diets, each mouse was injected 4 x 10(5) carcinoma cells into the right inguinal mammary fat pad. The primary tumors were excised when they reached a size of 1.0 cm in diameter. After surgery, mice were maintained on their respective diets for another three weeks. At necropsy, the incidence of metastasis, the number and size of macroscopic tumors, and the number of microscopic tumors in the lungs were determined. The incidence of mice with macroscopically visible tumors was 93%, 76%, and 67%, and the median number of macroscopic tumor was 5, 2, and 1 for the control, 10%, and 20% ISP groups (P < or = 0.05, 20% ISP vs. control). The median cross-sectional area of the macroscopic tumors was 0.93 mm2, 0.80 mm2, and 0.31 mm2, and the median volume was 0.73 mm3, 0.56 mm3, and 0.14 mm3 for the control, 10%, and 20% ISP groups (P < or = 0.01, 20% ISP vs. control). Histological examination revealed fewer microscopically detectable tumors in the ISP groups compared with the control. These results demonstrated that dietary supplementation with ISP reduced pulmonary metastasis of carcinoma cells from primary mammary tumors in BALB/c mice.

Expression of parathyroid hormone-related peptide (PthrP) and its receptor (PTH1R) during the histogenesis of cartilage and bone in the chicken mandibular process.

The purpose of this study was to examine the expression and actions of parathyroid hormone-related protein (PTHrP) when skeletal histogenesis occurs in the chicken mandible. Prior to the appearance of skeletal tissues, PTHrP and PTH1R were co-expressed by cells in the ectoderm, skeletal muscle, peripheral nerve and mesenchyme. Hyaline cartilage was first observed at HH stage 27 when many but not all chondroblasts expressed PTHrP and PTH1R. By stage 34, PTHrP and PTH1R were not detected in chondrocytes but were expressed in the perichondrium. Alkaline phosphatase (AP)-positive preosteoblasts and woven bone appeared at stages 31 and 34, respectively. Preosteoblasts, osteoblasts and osteocytes co-expressed PTHrP and PTH1R. Treatment with chicken PTHrP (1-36) increased cAMP in mesenchyme from stage 26 embryos. Continuous exposure to chicken PTHrP (1-36) for 14 days increased cartilage nodule number and decreased AP while intermittent exposure did not affect cartilage nodule number and increased AP in cultures of stage 26 mesenchymal cells. Adding a neutralizing anti-PTHrP antibody to the cultures reduced cartilage nodule number and did not affect AP. These findings show that PTHrP and PTH1R are co-expressed by extraskeletal and skeletal cells before and during skeletal tissue histogenesis, and that PTHrP may influence skeletal tissue histogenesis by affecting the differentiation of mandibular mesenchymal cells into chondroblasts and osteoblasts.