Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0153690 (bone metastases)
 6,382 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The LDL receptor-related protein 5 (LRP5) is a member of the LDL receptor family, which also includes the VLDL receptor and the apolipoprotein E receptor 2. The LRP5 is a co-receptor of Wnt located on the osteoblast membrane between two other receptors, Frizzled and Kremen. Frizzled and LRP5 bind to Wnt, thereby stabilizing beta-catenin and activating bone formation. When the dickkopf protein (Dkk) binds to Kremen and LRP5, this last undergoes internalization and therefore becomes unable to bind Wnt; this leads to degradation of beta-catenin and to inhibition of bone formation. In humans, loss of LRP5 function causes osteoporosis-pseudoglioma syndrome, which is characterized by congenital blindness and extremely severe childhood-onset osteoporosis (lumbar spine Z-score often < -4) with fractures. The G171V mutation prevents Dkk from binding to LRP5, thereby increasing LRP5 function; the result is high bone mass due to uncoupling of bone formation and resorption. The Z-scores in this condition can exceed +6 at the hip and spine. The LRP5 and Wnt/beta-catenin reflect the level of bone formation and play a central role in bone mass accrual and normal distribution. Furthermore, LRP5 may contribute to mediate mechanical loads within bone tissue. Identification of the Wnt/beta-catenin pathway is a breakthrough in the elucidation of pathophysiological mechanisms affecting bone tissue and suggests new treatment targets for patients with osteoporosis or specific malignant conditions such as myeloma and sclerotic bone metastases.
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PMID:LRP5 mutations in osteoporosis-pseudoglioma syndrome and high-bone-mass disorders. 1585 Sep 91

One of the least commonly encountered spindle cell tumors seen on prostatic needle biopsy or transurethral resection (TUR) of the prostate is solitary fibrous tumor (SFT). We studied 13 cases of SFTs identified on either prostate needle biopsy (n=9) or TUR of the prostate (n=4). Mean patient age at diagnosis was 63 years (range: 46 to 75 y; median: 65 y). Twelve men presented with urinary tract symptoms and 1 patient was biopsied during work-up of bone metastases. Ten cases were SFTs originating in the prostate, 2 cases arose between the prostate and rectum extending into the prostate (n=2), and 1 case was a pelvic mass without infiltration of the prostate. In 9 cases, a complete tumor resection was attempted by cystoprostatectomy (n=2), radical prostatectomy (n=4), pelvic exenteration (n=2), or pelvic tumor resection (n=1). Enucleation (n=1) and TUR (n=1) were performed in 2 other cases. Tumor sizes ranged from 8.5 to 15 cm in 7 radically resected cases. Mitotic rates were 3 to 5 per 10 high power fields in 5 cases, with the remaining cases having either rare (n=4) or no mitoses (n=4). Seven cases demonstrated areas of necrosis. Based on a combination of increased cellularity, mitotic activity, necrosis, nuclear pleomorphism, and infiltrativeness, 4 prostatic SFTs were malignant, 4 were benign, and 2 were borderline. Of the 3 non-prostatic SFTs, 1 was malignant and 2 were borderline. All tumors but 1 were immunoreactive for CD34 (n=12). Material for additional immunohistochemistry was available for the majority of cases with positive stains for Bcl-2 (11/11), CD99 (7/10), beta-catenin (5/10), and c-kit (0/11). Three SFTs demonstrated >or=10% p53 immunoreactivity including 1 tumor with 50% positivity; and 3 cases had Ki-67 rates of >or=20%. Although all SFTs were initially clinically considered to be of prostatic origin, some of the cases arose in the pelvis with secondary involvement of the prostate. Approximately 50% of prostatic SFTs were malignant. Even in the prostatic and nonprostatic SFTs with no overt malignant features, sometimes it was necessary to remove the prostate and in some instances the adjacent organs because of the large size of the tumors. SFTs must be differentiated from other spindle cell neoplasms of the prostate especially from gastrointestinal stromal tumors that may arise from the rectal wall with invasion of the prostate or from the region between the rectum and the prostate.
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PMID:Solitary fibrous tumor on needle biopsy and transurethral resection of the prostate: a clinicopathologic study of 13 cases. 1752 73

Most breast cancer metastases in bone form osteolytic lesions, but the mechanisms of tumor-induced bone resorption and destruction are not fully understood. Although it is well recognized that Wnt/beta-catenin signaling is important for breast cancer tumorigenesis, the role of this pathway in breast cancer bone metastasis is unclear. Dickkopf1 (Dkk1) is a secreted Wnt/beta-catenin antagonist. In the present study, we demonstrated that activation of Wnt/beta-catenin signaling enhanced Dkk1 expression in breast cancer cells and that Dkk1 overexpression is a frequent event in breast cancer. We also found that human breast cancer cell lines that preferentially form osteolytic bone metastases exhibited increased levels of Wnt/beta-catenin signaling and Dkk1 expression. Moreover, we showed that breast cancer cell-produced Dkk1 blocked Wnt3A-induced osteoblastic differentiation and osteoprotegerin (OPG) expression of osteoblast precursor C2C12 cells and that these effects could be neutralized by a specific anti-Dkk1 antibody. In addition, we found that breast cancer cell conditioned media were able to block Wnt3A-induced NF-kappaB ligand reduction in C2C12 cells. Finally, we demonstrated that conditioned media from breast cancer cells in which Dkk1 expression had been silenced via RNAi were unable to block Wnt3A-induced C2C12 osteoblastic differentiation and OPG expression. Taken together, these results suggest that breast cancer-produced Dkk1 may be an important mechanistic link between primary breast tumors and secondary osteolytic bone metastases.
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PMID:Breast cancer-derived Dickkopf1 inhibits osteoblast differentiation and osteoprotegerin expression: implication for breast cancer osteolytic bone metastases. 1854 62

To clarify the reciprocal interaction between human-breast cancer metastatic cells and bone microenvironment, we studied the influence of HGF/Met system on a proposed-prognostic marker of aggressiveness, the beta-catenin/Wnt pathway. For in vitro and in vivo experiments we used 1833-bone metastatic clone, derived from human-MDA-MB231 cells. In osteolytic bone metastases and in metastatic cells, Met was expressed in nuclei and at plasma membrane, and abnormally co-localised at nuclear level with beta-catenin and the tyrosine phosphorylated c-Src kinase. Thus, in 1833 cells nuclear-Met COOH-terminal fragment and beta-catenin-TCF were constitutively activated, possibly by receptor and non-receptor tyrosine kinases. The activity of the gene reporter TOPFLASH (containing multiple TCF/LEF-consensus sites) was measured, as index of beta-catenin functionality. In 1833 cells, human and mouse HGF increased Met and beta-catenin tyrosine phosphorylation and expression in nuclear and perinuclear compartments, beta-catenin nuclear translocation via Kank and TOPFLASH transactivation. Human HGF was autocrine/intracrine in bone metastasis, and mouse HGF originating from the adjacent host-bone marrow, was found inside the metastatic nuclei. Parental MDA-MB231 cell nuclei did not show functional beta-catenin, for TCF-transactivating activity, and the regulation by HGF. Our study highlighted the importance of the metastasis-stroma interaction in human-breast cancer metastatisation and first identified the HGF/nuclear Met/phospho-c-Src/beta-catenin-TCF/Wnt pathway as a potential-therapeutic target to delay establishment/progression of bone metastases by affecting the aggressive phenotype.
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PMID:Interaction between human-breast cancer metastasis and bone microenvironment through activated hepatocyte growth factor/Met and beta-catenin/Wnt pathways. 2035 Aug 2

Cell adhesion molecules have been implicated in the colonization of cancer cells to distant organs. Prostate cancer (PCa) has a propensity to metastasize to bone, and cadherin-11, which is an osteoblast cadherin aberrantly expressed in PCa cells derived from bone metastases, has been shown to play a role in the metastasis of PCa cells to bone. However, the mechanism by which cadherin-11 is involved in this process is not known. Here, we show that expression of cadherin-11 in cadherin-11-negative C4-2B4 cells increases their spreading and intercalation into an osteoblast layer and also stimulates C4-2B4 cell migration and invasiveness. The downregulation of cadherin-11 in cadherin-11-expressing metastatic PC3 cells decreases cell motility and invasiveness. Further, both the juxtamembrane (JMD) and beta-catenin binding domains (CBS) in the cytoplasmic tail of cadherin-11 are required for cell migration and invasion, but not spreading. Gene array analyses showed that several invasion-related genes, including MMP-7 and MMP-15, are upregulated in cadherin-11-expressing, but not in cad11-DeltaJMD-expressing or cad11-DeltaCBS-expressing, C4-2B4 cells. These observations suggest that cadherin-11 not only provides a physical link between PCa cells and osteoblasts but also increases PCa cell motility and invasiveness that may facilitate the metastatic colonization of PCa cells in bone.
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PMID:Cadherin-11 increases migration and invasion of prostate cancer cells and enhances their interaction with osteoblasts. 2048 40