Jussi Halleen - Profile on Academia.edu (original) (raw)
Papers by Jussi Halleen
Tartrate-resistant acid phosphatase 5B is a specific and sensitive marker of bone resorption
Anticancer research
Bone resorbing osteoclasts contain high amounts of tartrate-resistant acid phosphatase (TRACP) 5b... more Bone resorbing osteoclasts contain high amounts of tartrate-resistant acid phosphatase (TRACP) 5b and secrete it into the blood circulation. Circulating TRACP 5b activity is derived exclusively from osteoclasts. We have developed a TRACP 5b-specific-immunoassay using a monoclonal antibody O1A that was developed using TRACP 5b purified from human osteoclasts as antigen. Serum TRACP 5b activity has a low diurnal variability, and it does not accumulate in the circulation in renal or hepatic failure. It is elevated in 80% of patients with osteoporosis, while decreased 40-50% after antiresorptive therapy with estrogen and the bisphosphonate alendronate. Preliminary results show that serum TRACP 5b activity is normal in breast cancer patients without bone metastases, and elevated in approximately 80% of breast cancer patients with bone metastases. These results suggest that serum TRACP 5b activity may be a useful marker for the early detection of the spreading of breast cancer cells to bone.
Specificity and clinical performance of two commercial TRACP 5b immunoassays
Clinical laboratory
Two forms of tartrate-resistant acid phosphatase (TRACP) circulate in human blood, TRACP 5a deriv... more Two forms of tartrate-resistant acid phosphatase (TRACP) circulate in human blood, TRACP 5a derived from inflammatory macrophages and TRACP 5b derived from osteoclasts. Serum TRACP 5b is a clinically useful marker of osteoclast number and bone resorption. We have studied TRACP 5b specificity of two commercially available immunoassays that are stated to be TRACP 5b specific, the BoneTRAP assay and the MetraTRAP5b assay, and investigated their clinical performance for monitoring the efficacy of alendronate treatment. Both assays bound TRACP 5b equally and had similar cross-reactivity to TRACP 5a. The mean decrease in the alendronate group was higher with the MetraTRAP5b assay, but the clinical performance of the two assays for monitoring alendronate treatment was equal due to higher variability of the MetraTRAP5b assay. We conclude that the BoneTRAP assay and the MetraTRAP5b assay have similar specificity for TRACP 5b, and similar clinical performance for monitoring alendronate treatment.
Anticancer research
Background: The purpose of this cross-sectional study was to evaluate the value of serum tartrate... more Background: The purpose of this cross-sectional study was to evaluate the value of serum tartrate-resistant acid phosphatase 5b (TRACP 5b) and carboxyterminal telopeptide of type I collagen (ICTP) separately and in combination as markers of bone metastases compared to total alkaline phosphatase (tALP) in breast cancer. Materials and Methods: Two groups of patients were studied, one with verified bone metastases (N=46) and one without bone metastases (N=141). Bone marker levels were correlated with the presence or absence of bone metastases. Results: Serum TRACP 5b concentrations exhibited the largest area under the receiver-operating characteristics (ROC) curve (AUC=0.845), followed by ICTP (0.818) and tALP (0.814) when all patients were included in the analysis. With the combination of TRACP 5b and ICTP, the AUC increased to 0.881. In multivariate regression analysis, all three markers were significant predictors of bone metastases. Conclusion: Serum TRACP 5b, ICTP and tALP exhibited equal performances in the detection of bone metastases. The combination of TRACP with ICTP did not significantly improve the detection of bone metastases over tALP.
Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomark... more Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomarkers are indicators of bone metabolic ac- tivity, but their value in predicting bone quality has not been studied in growing girls. Objective: This study examines the association of sex hormones and bone markers with bone geometry and density in pubertal girls. Design:
Biochemical and Biophysical Research Communications
Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed specifically in osteoclasts and... more Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed specifically in osteoclasts and activated macrophages, two phagocytosing cell types originating from the same hematopoietic stem cells. TRAP contains a binuclear iron centre which has been shown to generate reactive oxygen species (ROS). In this study murine macrophage like cell line RAW-264 overexpressing TRAP was shown to produce elevated levels of hydroxyl radicals compared to parental cells. TRAP transfected cells also had reduced growth rate indicating harmful effects of excessive intracellular ROS levels. Using TRAP specific antibody TRAP protein was shown in alveolar macrophages partially colocalize with late endosomal/lysosomal markers Rab7, Lamp 1 and MHC II molecules that bind antigenic peptides. TRAP also colocalized into compartments where Staphylococcus aureus were phagocytosed. These results suggest that TRAP may have an important biological function in the defence mechanism of macrophages by generating ...
Endocrinology
Decreased E2 levels after menopause cause bone loss through increased penetrative resorption. The... more Decreased E2 levels after menopause cause bone loss through increased penetrative resorption. The reversal effect of E2 substitution therapy is well documented in vivo, although the detailed mechanism of action is not fully understood. To study the effects of E2 on bone resorption, we developed a novel in vitro bone resorption assay in which degradation of inorganic and organic matrix could be measured separately. E2 treatment significantly decreased the depth of resorption pits, although the area resorbed was not changed. Electron microscopy further revealed that the resorption pits were filled with nondegraded collagen, suggesting that E2 disturbed the organic matrix degradation. Two major groups of proteinases, matrix metalloproteinases (MMPs) and cysteine proteinases, have been suggested to participate in organic matrix degradation by osteoclasts. We show here that MMP-9 released a cross-linked carboxyl-terminal telopeptide of type I collagen from bone collagen, and cathepsin K ...
Journal of Endocrinology
There are two known estrogen receptors, estrogen receptor-alpha (ER alpha) and estrogen receptor-... more There are two known estrogen receptors, estrogen receptor-alpha (ER alpha) and estrogen receptor-beta (ER beta), which may mediate the actions of estrogen. The aim of the present study was to compare fat content, skeletal growth and adult bone metabolism in female mice lacking ER alpha (ERKO), ER beta (BERKO) or both ERs (DERKO). We demonstrate that endogenous estrogens decrease the fat content in female mice via ER alpha and not ER beta. Interestingly, the longitudinal bone growth was decreased in ERKO, increased in BERKO, but was intermediate in DERKO females, demonstrating that ER alpha and ER beta exert opposing effects in the regulation of longitudinal bone growth. The effects on longitudinal bone growth were correlated with similar effects on serum levels of IGF-I. A complex regulation of the trabecular bone mineral density (BMD), probably caused by a disturbed feedback regulation of estrogen and testosterone, was observed in female ER-inactivated mice. Nevertheless, a partial...
Abstract 3842: Culturing cancer cells on myoma tissue: Development of a novel fully human organotypic 3D invasion model applicable as a preclinical tool for cancer drug development
Cancer Research, 2013
Abstract 2080: Inhibiting androgen receptor-associated Src signaling by VAL201 inhibits prostate cancer metastasis in an orthotopic mouse model
Cancer Research, 2013
Abstract 1803: A new spectrum-selective cathepsin inhibitor, VBY-825, inhibits bone destruction in a syngeneic 5TGM1 multiple myeloma mouse model
Cancer Research, 2014
Abstract 922: Inhibiting androgen receptor associated Src signaling with VAL201 inhibits breast cancer growth in an orthotopic xenograft model
Cancer Research, 2013
Models and screening assays for drug discovery in osteoporosis
Expert opinion on drug discovery, 2010
Osteoporosis affects nearly 100 million people in Europe, Japan and the US, and the number is inc... more Osteoporosis affects nearly 100 million people in Europe, Japan and the US, and the number is increasing due to aging of the population. Preclinical efficacy studies performed according to regulatory guidelines are large, long and expensive, and there is a need for guidance and recommendations on how to perform preliminary studies prior to the regulatory studies. We review research models that can be used for preclinical efficacy testing of new drug candidates for osteoporosis. Our focus is on testing compounds targeted to directly decrease osteoclastic bone resorption or increase osteoblastic bone formation. We provide an overview of in vitro bone cell culture systems and osteoporosis animal models useful for preclinical efficacy studies and a step-by-step approach on how the most interesting compound can be selected from thousands of drug candidates. Different approaches for testing anti-catabolic and anabolic compounds are provided. Efficacy of new osteoporosis drug candidates ca...
Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls
The American journal of clinical nutrition, 2003
Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] ... more Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. The subjects were 10-12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (+/- SD) dietary calcium intake of 733 +/- 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were assessed by using different methods. Thirty-two percent of the girls were vitamin D deficient [serum 25(OH)D < or = 25 nmol/L], and 46% of the girls had an insufficient concentration (26-40 nmol/L). iPTH and TRAP 5b concentrations were significantly higher in the deficient group than in the insufficient and sufficient groups ...
Increased osteoclast activity is associated with aggressiveness of osteosarcoma
International Journal of Oncology, 1992
Osteosarcoma (OS) is a highly malignant primary skeletal tumor with a striking tendency to rapidl... more Osteosarcoma (OS) is a highly malignant primary skeletal tumor with a striking tendency to rapidly destroy the surrounding bone and metastasize, since metastases are frequently present at clinical onset. The basis for the aggressiveness of this tumor is largely unknown. However, recent studies in in vivo models indicate that the anti-osteolytic drugs, bisphosphonates, can inhibit the tumor local expansion and the formation of metastases. We further investigated the association between the presence of active osteoclasts and the aggressiveness of OS. We evaluated the presence of osteoclasts and the mRNA of different osteoclast-related genes in tumor biopsies from 16 OS patients and in three OS cell lines and the serum levels of bone resorption markers in the same series and in 28 other patients. Tumor-associated osteoclasts were found in 63 and 75% of cases by histological and mRNA analysis. Among different serum markers, only MMP-9 was significantly higher in OS cases (p=0.0001), whereas TRACP 5b was significantly higher in metastatic patients compared to nonmetastatic patients (p=0.0509). Serum TRACP 5b was significantly correlated to serum NTX (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001) and cathepsin K mRNA in tumor tissues (p=0.0153). In 8 patients we also analyzed TRACP 5b serum level at follow-up and we verified a significant decrease of TRACP 5b after primary tumor removal (p=0.0117). In conclusion, tumor-infiltrating osteoclasts are frequently found in OS and increased serum TRACP 5b levels and the presence of active osteoclast at primary sites were positively associated with tumor aggressiveness.
Clinical chemistry, 2000
Osteoclasts secrete tartrate-resistant acid phosphatase (TRAP; EC 3.1.3.2) 5b into the circulatio... more Osteoclasts secrete tartrate-resistant acid phosphatase (TRAP; EC 3.1.3.2) 5b into the circulation. We studied the release of TRAP 5b from osteoclasts using a mouse in vitro osteoclast differentiation assay. We developed and characterized a polyclonal antiserum in rabbits, using purified human osteoclastic TRAP 5b as antigen. The antiserum was specific for TRAP in Western analysis of mouse osteoclast culture medium and was used to develop an immunoassay. We cultured mouse bone marrow-derived osteoclast precursor cells for 3-7 days with or without clodronate in the presence of vitamin D and analyzed the number of osteoclasts formed and the amount of TRAP 5b activity released into the culture medium. TRAP 5b activity was not secreted from osteoclast precursor cells. Addition of clodronate-containing liposomes decreased in a dose-dependent manner the number of osteoclasts and TRAP 5b activity released in 6-day cultures. The amount of TRAP 5b activity in the medium detected by the immun...
Intracellular degradation of osteoclast bone resorption products by hydroxyl radicals generated by tartrate-resistant acid phosphatase
Pathophysiology, 1998
Osteoporosis International, 2011
Sagopilone, a fully synthetic epothilone and very potent anti-tumor agent, has proved to be effic... more Sagopilone, a fully synthetic epothilone and very potent anti-tumor agent, has proved to be efficient in inhibiting bone destruction and tumor burden in a mouse model of breast cancer bone metastasis. In addition to its antiproliferative effects, this study shows direct effects of sagopilone on bone resorption and osteoclast activity.
Nucleic Acids Research, 1995
Tartrate-resistant acid phosphatase 5B is a specific and sensitive marker of bone resorption
Anticancer research
Bone resorbing osteoclasts contain high amounts of tartrate-resistant acid phosphatase (TRACP) 5b... more Bone resorbing osteoclasts contain high amounts of tartrate-resistant acid phosphatase (TRACP) 5b and secrete it into the blood circulation. Circulating TRACP 5b activity is derived exclusively from osteoclasts. We have developed a TRACP 5b-specific-immunoassay using a monoclonal antibody O1A that was developed using TRACP 5b purified from human osteoclasts as antigen. Serum TRACP 5b activity has a low diurnal variability, and it does not accumulate in the circulation in renal or hepatic failure. It is elevated in 80% of patients with osteoporosis, while decreased 40-50% after antiresorptive therapy with estrogen and the bisphosphonate alendronate. Preliminary results show that serum TRACP 5b activity is normal in breast cancer patients without bone metastases, and elevated in approximately 80% of breast cancer patients with bone metastases. These results suggest that serum TRACP 5b activity may be a useful marker for the early detection of the spreading of breast cancer cells to bone.
Specificity and clinical performance of two commercial TRACP 5b immunoassays
Clinical laboratory
Two forms of tartrate-resistant acid phosphatase (TRACP) circulate in human blood, TRACP 5a deriv... more Two forms of tartrate-resistant acid phosphatase (TRACP) circulate in human blood, TRACP 5a derived from inflammatory macrophages and TRACP 5b derived from osteoclasts. Serum TRACP 5b is a clinically useful marker of osteoclast number and bone resorption. We have studied TRACP 5b specificity of two commercially available immunoassays that are stated to be TRACP 5b specific, the BoneTRAP assay and the MetraTRAP5b assay, and investigated their clinical performance for monitoring the efficacy of alendronate treatment. Both assays bound TRACP 5b equally and had similar cross-reactivity to TRACP 5a. The mean decrease in the alendronate group was higher with the MetraTRAP5b assay, but the clinical performance of the two assays for monitoring alendronate treatment was equal due to higher variability of the MetraTRAP5b assay. We conclude that the BoneTRAP assay and the MetraTRAP5b assay have similar specificity for TRACP 5b, and similar clinical performance for monitoring alendronate treatment.
Anticancer research
Background: The purpose of this cross-sectional study was to evaluate the value of serum tartrate... more Background: The purpose of this cross-sectional study was to evaluate the value of serum tartrate-resistant acid phosphatase 5b (TRACP 5b) and carboxyterminal telopeptide of type I collagen (ICTP) separately and in combination as markers of bone metastases compared to total alkaline phosphatase (tALP) in breast cancer. Materials and Methods: Two groups of patients were studied, one with verified bone metastases (N=46) and one without bone metastases (N=141). Bone marker levels were correlated with the presence or absence of bone metastases. Results: Serum TRACP 5b concentrations exhibited the largest area under the receiver-operating characteristics (ROC) curve (AUC=0.845), followed by ICTP (0.818) and tALP (0.814) when all patients were included in the analysis. With the combination of TRACP 5b and ICTP, the AUC increased to 0.881. In multivariate regression analysis, all three markers were significant predictors of bone metastases. Conclusion: Serum TRACP 5b, ICTP and tALP exhibited equal performances in the detection of bone metastases. The combination of TRACP with ICTP did not significantly improve the detection of bone metastases over tALP.
Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomark... more Context: The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomarkers are indicators of bone metabolic ac- tivity, but their value in predicting bone quality has not been studied in growing girls. Objective: This study examines the association of sex hormones and bone markers with bone geometry and density in pubertal girls. Design:
Biochemical and Biophysical Research Communications
Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed specifically in osteoclasts and... more Tartrate-resistant acid phosphatase (TRAP) is an enzyme expressed specifically in osteoclasts and activated macrophages, two phagocytosing cell types originating from the same hematopoietic stem cells. TRAP contains a binuclear iron centre which has been shown to generate reactive oxygen species (ROS). In this study murine macrophage like cell line RAW-264 overexpressing TRAP was shown to produce elevated levels of hydroxyl radicals compared to parental cells. TRAP transfected cells also had reduced growth rate indicating harmful effects of excessive intracellular ROS levels. Using TRAP specific antibody TRAP protein was shown in alveolar macrophages partially colocalize with late endosomal/lysosomal markers Rab7, Lamp 1 and MHC II molecules that bind antigenic peptides. TRAP also colocalized into compartments where Staphylococcus aureus were phagocytosed. These results suggest that TRAP may have an important biological function in the defence mechanism of macrophages by generating ...
Endocrinology
Decreased E2 levels after menopause cause bone loss through increased penetrative resorption. The... more Decreased E2 levels after menopause cause bone loss through increased penetrative resorption. The reversal effect of E2 substitution therapy is well documented in vivo, although the detailed mechanism of action is not fully understood. To study the effects of E2 on bone resorption, we developed a novel in vitro bone resorption assay in which degradation of inorganic and organic matrix could be measured separately. E2 treatment significantly decreased the depth of resorption pits, although the area resorbed was not changed. Electron microscopy further revealed that the resorption pits were filled with nondegraded collagen, suggesting that E2 disturbed the organic matrix degradation. Two major groups of proteinases, matrix metalloproteinases (MMPs) and cysteine proteinases, have been suggested to participate in organic matrix degradation by osteoclasts. We show here that MMP-9 released a cross-linked carboxyl-terminal telopeptide of type I collagen from bone collagen, and cathepsin K ...
Journal of Endocrinology
There are two known estrogen receptors, estrogen receptor-alpha (ER alpha) and estrogen receptor-... more There are two known estrogen receptors, estrogen receptor-alpha (ER alpha) and estrogen receptor-beta (ER beta), which may mediate the actions of estrogen. The aim of the present study was to compare fat content, skeletal growth and adult bone metabolism in female mice lacking ER alpha (ERKO), ER beta (BERKO) or both ERs (DERKO). We demonstrate that endogenous estrogens decrease the fat content in female mice via ER alpha and not ER beta. Interestingly, the longitudinal bone growth was decreased in ERKO, increased in BERKO, but was intermediate in DERKO females, demonstrating that ER alpha and ER beta exert opposing effects in the regulation of longitudinal bone growth. The effects on longitudinal bone growth were correlated with similar effects on serum levels of IGF-I. A complex regulation of the trabecular bone mineral density (BMD), probably caused by a disturbed feedback regulation of estrogen and testosterone, was observed in female ER-inactivated mice. Nevertheless, a partial...
Abstract 3842: Culturing cancer cells on myoma tissue: Development of a novel fully human organotypic 3D invasion model applicable as a preclinical tool for cancer drug development
Cancer Research, 2013
Abstract 2080: Inhibiting androgen receptor-associated Src signaling by VAL201 inhibits prostate cancer metastasis in an orthotopic mouse model
Cancer Research, 2013
Abstract 1803: A new spectrum-selective cathepsin inhibitor, VBY-825, inhibits bone destruction in a syngeneic 5TGM1 multiple myeloma mouse model
Cancer Research, 2014
Abstract 922: Inhibiting androgen receptor associated Src signaling with VAL201 inhibits breast cancer growth in an orthotopic xenograft model
Cancer Research, 2013
Models and screening assays for drug discovery in osteoporosis
Expert opinion on drug discovery, 2010
Osteoporosis affects nearly 100 million people in Europe, Japan and the US, and the number is inc... more Osteoporosis affects nearly 100 million people in Europe, Japan and the US, and the number is increasing due to aging of the population. Preclinical efficacy studies performed according to regulatory guidelines are large, long and expensive, and there is a need for guidance and recommendations on how to perform preliminary studies prior to the regulatory studies. We review research models that can be used for preclinical efficacy testing of new drug candidates for osteoporosis. Our focus is on testing compounds targeted to directly decrease osteoclastic bone resorption or increase osteoblastic bone formation. We provide an overview of in vitro bone cell culture systems and osteoporosis animal models useful for preclinical efficacy studies and a step-by-step approach on how the most interesting compound can be selected from thousands of drug candidates. Different approaches for testing anti-catabolic and anabolic compounds are provided. Efficacy of new osteoporosis drug candidates ca...
Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early pubertal and prepubertal Finnish girls
The American journal of clinical nutrition, 2003
Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] ... more Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. The subjects were 10-12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (+/- SD) dietary calcium intake of 733 +/- 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were assessed by using different methods. Thirty-two percent of the girls were vitamin D deficient [serum 25(OH)D < or = 25 nmol/L], and 46% of the girls had an insufficient concentration (26-40 nmol/L). iPTH and TRAP 5b concentrations were significantly higher in the deficient group than in the insufficient and sufficient groups ...
Increased osteoclast activity is associated with aggressiveness of osteosarcoma
International Journal of Oncology, 1992
Osteosarcoma (OS) is a highly malignant primary skeletal tumor with a striking tendency to rapidl... more Osteosarcoma (OS) is a highly malignant primary skeletal tumor with a striking tendency to rapidly destroy the surrounding bone and metastasize, since metastases are frequently present at clinical onset. The basis for the aggressiveness of this tumor is largely unknown. However, recent studies in in vivo models indicate that the anti-osteolytic drugs, bisphosphonates, can inhibit the tumor local expansion and the formation of metastases. We further investigated the association between the presence of active osteoclasts and the aggressiveness of OS. We evaluated the presence of osteoclasts and the mRNA of different osteoclast-related genes in tumor biopsies from 16 OS patients and in three OS cell lines and the serum levels of bone resorption markers in the same series and in 28 other patients. Tumor-associated osteoclasts were found in 63 and 75% of cases by histological and mRNA analysis. Among different serum markers, only MMP-9 was significantly higher in OS cases (p=0.0001), whereas TRACP 5b was significantly higher in metastatic patients compared to nonmetastatic patients (p=0.0509). Serum TRACP 5b was significantly correlated to serum NTX (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.0001) and cathepsin K mRNA in tumor tissues (p=0.0153). In 8 patients we also analyzed TRACP 5b serum level at follow-up and we verified a significant decrease of TRACP 5b after primary tumor removal (p=0.0117). In conclusion, tumor-infiltrating osteoclasts are frequently found in OS and increased serum TRACP 5b levels and the presence of active osteoclast at primary sites were positively associated with tumor aggressiveness.
Clinical chemistry, 2000
Osteoclasts secrete tartrate-resistant acid phosphatase (TRAP; EC 3.1.3.2) 5b into the circulatio... more Osteoclasts secrete tartrate-resistant acid phosphatase (TRAP; EC 3.1.3.2) 5b into the circulation. We studied the release of TRAP 5b from osteoclasts using a mouse in vitro osteoclast differentiation assay. We developed and characterized a polyclonal antiserum in rabbits, using purified human osteoclastic TRAP 5b as antigen. The antiserum was specific for TRAP in Western analysis of mouse osteoclast culture medium and was used to develop an immunoassay. We cultured mouse bone marrow-derived osteoclast precursor cells for 3-7 days with or without clodronate in the presence of vitamin D and analyzed the number of osteoclasts formed and the amount of TRAP 5b activity released into the culture medium. TRAP 5b activity was not secreted from osteoclast precursor cells. Addition of clodronate-containing liposomes decreased in a dose-dependent manner the number of osteoclasts and TRAP 5b activity released in 6-day cultures. The amount of TRAP 5b activity in the medium detected by the immun...
Intracellular degradation of osteoclast bone resorption products by hydroxyl radicals generated by tartrate-resistant acid phosphatase
Pathophysiology, 1998
Osteoporosis International, 2011
Sagopilone, a fully synthetic epothilone and very potent anti-tumor agent, has proved to be effic... more Sagopilone, a fully synthetic epothilone and very potent anti-tumor agent, has proved to be efficient in inhibiting bone destruction and tumor burden in a mouse model of breast cancer bone metastasis. In addition to its antiproliferative effects, this study shows direct effects of sagopilone on bone resorption and osteoclast activity.
Nucleic Acids Research, 1995