Flubendazole,FDA-approved anthelmintic,targets breast cancer stem-like cells

Cancer stem-like cell (CS-like cell) is considered to be responsible for recurrence and drug resistance events in breast cancer, which makes it a potential target for novel cancer therapeutic strategy. The FDA approved flubendazole, has been widely used in the treatment of intestinal parasites. Here, we demonstrated a novel effect of flubendazole on breast CS-like cells. Flubendazole inhibited breast cancer cells proliferation in dose- and time-dependent manner and delayed tumor growth in xenograft models by intraperitoneal injection. Importantly, flubendazole reduced CD44^high/CD24^low subpopulation and suppressed the formation of mammosphere and the expression of self-renewal related genes including c-myc, oct4, sox2, nanog and cyclinD1. Moreover, we found that flubendazole induced cell differentiation and inhibited cell migration. Consistently, flubendazole reduced mesenchymal markers (β-catenin, N-cadherin and Vimentin) expression and induced epithelial and differentiation marker (Keratin 18) expression in breast cancer cells. Mechanism study revealed that flubendazole arrested cell cycle at G2/M phase and induced monopolar spindle formation through inhibiting tubulin polymerization. Furthermore, flubendazole enhanced cytotoxic activity of conventional therapeutic drugs fluorouracil and doxorubicin against breast cancer cells. In conclusion, our findings uncovered a remarkable effect of flubendazole on suppressing breast CS-like cells, indicating a novel utilization of flubendazole in breast cancer therapy.     

Sclerostin blockade promotes bone metastases of Wnt-responsive breast cancer cells

The secreted protein sclerostin is primarily produced by osteocytes and suppresses osteoblast differentiation and function by inhibiting the canonical Wnt signaling pathway. Genetic and pharmacological inhibition of sclerostin has been shown to increase bone formation and an anti-sclerostin antibody has been clinically approved for the treatment of osteoporosis. Canonical Wnt signaling is also involved in the progression of several types of cancers including breast cancer. Here, we studied the effects of sclerostin inhibition on the development of bone metastases of breast cancer using mouse models. TOPFLASH assay and real-time PCR analysis of AXIN2, a target of canonical Wnt signaling, revealed that, among four cell lines tested, MDA-MB-231 human breast cancer cells responded highly to the canonical Wnt ligand Wnt3a, whereas other cell lines exhibited marginal responses. Consistent with these results, treatment with an anti-sclerostin antibody significantly increased the bone metastases of MDA-MB-231 but not those of other breast cancer cells. Immunohistochemical studies demonstrated that an anti-sclerostin antibody induced intracellular accumulation of β-catenin in bone-colonized MDA-MB-231 cells. Suspension culture assays showed that Wnt3a accelerated the tumorsphere formation of MDA-MB-231 cells, whereas monolayer cell proliferation and migration were not affected. Furthermore, the numbers of osteoclasts and their precursor cells in bone metastases of MDA-MB-231 were significantly increased in mice treated with an anti-sclerostin antibody. These results collectively suggest that sclerostin blockade activates canonical Wnt signaling in ligand-responsive breast cancer cells metastasized to bone, thereby increasing bone metastases, likely to have been mediated at least in part by enhancing stem cell-like properties of cancer cells and osteoclastogenesis.     

OPG‐Fc inhibits ovariectomy‐induced growth of disseminated breast cancer cells in bone

Dormant disseminated tumour cells can be detected in the bone marrow of breast cancer patients several years after resection of the primary tumour. The majority of these patients will remain asymptomatic, however, ～15% will go on to develop overt bone metastases and this condition is currently incurable. The reason why these dormant cells are stimulated to proliferate and form bone tumours in some patients and not others remains to be elucidated. We have recently shown that in an in vivo model, increasing bone turnover by ovariectomy stimulated proliferation of disseminated tumour cells, resulting in formation of bone metastasis. We now show for the first time that osteoclast mediated mechanisms induce growth of tumours from dormant MDA‐MB‐231 cells disseminated in the bone. We also show that disruption of RANK–RANKL interactions following administration of OPG‐Fc inhibits growth of these dormant tumour cells in vivo. Our data support early intervention with anti‐resorptive therapy in a low‐oestrogen environment to prevent development of bone metastases.     

乳腺癌骨转移分子机制的研究进展

乳腺癌是女性最易患的恶性肿瘤,且发病率呈逐年上升趋势.大约有70%的患者在晚期发生骨转移,乳腺癌骨转移不仅可导致患者遭受贫血、骨折、截瘫、高血钙、疼痛和恶病质等痛苦,也是导致死亡率上升的重要原因.乳腺癌骨转移可分为若干个步骤,此篇综述介绍癌细胞的骨定向迁移及乳腺癌细胞和骨微环境的交互作用中涉及的重要因子.     

Cardamonin reduces chemotherapy-enriched breast cancer stem-like cells in vitro and in vivo

The failure of cytotoxic chemotherapy in breast cancers has been closely associated with the presence of drug resistant cancer stem cells (CSCs). Thus, screening for small molecules that selectively inhibit growth of CSCs may offer great promise for cancer control, particularly in combination with chemotherapy. In this report, we provide the first demonstration that cardamonin, a small molecule, selectively inhibits breast CSCs that have been enriched by chemotherapeutic drugs. In addition, cardamonin also sufficiently prevents the enrichment of CSCs when simultaneously used with chemotherapeutic drugs. Specifically, cardamonin effectively abolishes chemotherapeutic drug-induced up-regulation of IL-6, IL-8 and MCP-1 and activation of NF-κB/IKBα and Stat3. Furthermore, in a xenograft mouse model, co-administration of cardamonin and the chemotherapeutic drug doxorubicin significantly retards tumor growth and simultaneously decreases CSC pools in vivo. Since cardamonin has been found in some herbs, this work suggests a potential new approach for the effective treatment of breast CSCs by administration of cardamonin either concurrent with or after chemotherapeutic drugs.     

胫骨内接种建立乳腺癌骨转移大鼠模型的特点

目的研究胫骨内接种MRMT-1细胞制作的乳腺癌骨转移大鼠模型在行为学、影像学、核医学、病理学和分子生物学等方面的特点。方法使用雌性SD大鼠,随机分为假手术组和模型组,使用胫骨内注射法制成乳腺癌骨转移模型。造模后第19天时进行疼痛测定;第21天取材,测定肿瘤体积,通过影像技术评估骨质缺损程度,核医学测定骨矿物质含量(BMC)和骨密度(BMD),HE染色观察形态,抗酒石酸酸性磷酸酶(TRAP)染色并计数破骨细胞,免疫组化法测定增殖细胞核抗原(PCNA)、护骨素(OPG)和核因子kB受体活化因子配体(RANKL),荧光实时定量RT-PCR测定甲状旁腺激素相关蛋白(PTHrP)。结果模型组在造模后第19天已出现机械痛觉超敏、机械痛觉过敏和热痛觉过敏(P0.01)。第21天取材后胫骨影像评分升高(P0.01),BMD下降(P0.05);肉眼观察肿瘤生长明显(P0.01),镜下可见溶骨病变为主的混合性骨质破坏;破骨细胞数量和活性增加(P0.01),PTHrP、OPG水平与OPG/RANKL比值均下降(P0.05、P0.01),而RANKL无明显变化。结论乳腺癌骨转移大鼠模型具有疼痛和骨质破坏的表现,但未表现出PTHrP和RANKL升高,其损伤途径是通过抑制OPG破坏了OPG-RANKL-RANK系统的平衡,引起破骨细胞过度激活,造成骨吸收作用亢进。     

乳腺癌骨转移机制研究进展

乳腺癌是一种容易发生骨转移的女性常见恶性肿瘤。乳腺癌细胞的特异性、骨微环境及两者间相互作用是形成骨转移的共同因素。乳腺癌细胞表达的趋化因子受体、整合素、溶骨因子和成骨因子等使肿瘤细胞易于扩散到骨,而骨微环境可以为肿瘤细胞的生长提供丰富的生长因子和细胞因子。一旦乳腺癌细胞侵入骨质,肿瘤细胞分泌的因子就会作用于骨的外在结构和内在结构（如造血干细胞、T细胞、血小板、内皮细胞等）,使骨质破坏且分泌相关因子反作用于癌细胞,从而引起转移的级联反应和恶性循环形成。     

145例乳腺癌骨转移临床病理分析

目的：探讨乳腺癌骨转移的相关因素及处理对策。方法：本文对１９５４年１月～１９７７年１２月我院收治的２８０３例原发乳腺癌术后发生骨转移的１４５例患者临床资料进行回顾性分析。结果：乳腺癌术后骨转移发生率５．１％,骨转移部位分布较广泛,多数出现在脊柱,术后前５年发生率占７６．４％,腋淋巴结阳性患者较阴性患者较早发生转移。出现转移后经治疗患者较未治疗患者生存期有显著性差异。结论：乳腺癌术后骨转移出现时间与其分布有其规律,综合治疗后乳腺癌患者可延缓出现转移的时间。出现骨转移后,积极治疗,可达到延长生存期改善生存质量的目的。     

Breast cancer stem-like cells and breast cancer therapy

<正>Until the early 1990s,human cancers were considered a morphologically heterogeneous population of cells.In 1997,Bonnet et al[1] demonstrated that a small population of leukemia cells was able to differentiate in vivo into leukemic blasts,indicating that the leukemic clone was organized as a hierarchy;this was subsequently denoted as cancer     

Cellular interactions in the tropism of prostate cancer to bone

At autopsy >or=80% of prostate cancers have established macrometastases in marrow containing bone. The mechanism(s) to explain this remarkable level of bone involvement remain to be elucidated. We examined the adhesive and invasive behavior of prostate cancer cells to osteoblastic and human bone marrow endothelial cells (HBME-1) in an attempt to explain the tropism of prostate cells for bone. We found an inverse relationship between adhesion and prostate cell tumorigenicity and metastatic potential. Relative cell adhesion of P69 between cell lines was 1.74-fold (95% confidence interval [CI] = 1.15-2.64) and 1.58-fold (95% CI = 0.94-2.68) greater at 1 hr and 2 hr, respectively, than LNCaP that was essentially equivalent to C4-2 cells when using an osteoblastic cell line, D1 as the substrate. Similar results were acquired when HBME-1 were used as substratum. There was a marked increase in adhesion of the poorly tumorigenic cell line P69 as compared to the cancer cells to HBME-1. P69 adhesion was 2.78-fold (95% CI = 1.87-4.84) and 2.0-fold (95% CI = 1.43-2.80) greater at 1 hr and 2 hr, respectively when compared to LNCaP or C4-2 cells. D1 cells, a bone homing osteoblastic precursor, behaved contrary to the metastatic, bone-colonizing C4-2 cell line and bound best to other bone cells but not as well as a non-homing fetal bone marrow-derived cell line, D2. Invasion of prostate cancer cells through HBME-1 lawns was examined at 8 hr and 16 hr. In contrast to the adhesion studies, the invasion of the more aggressive C4-2 cells was 3.46-fold (95% CI = 1.18-10.17) and 2.65-fold (95% CI = 1.26-5.56) greater at 8 hr and 16 hr, respectively than LNCaP cells. Similarly, LNCaP cell invasion was 1.73-fold (95% CI = 0.69-4.37) and 2.35-fold (95% CI = 1.41-3.93) greater at 8 hr and 16 hr, respectively than P69 cells at the invasion of HBME-1 monolayers. At 8 hr, C4-2 cells had 6.0-fold (95% CI = 2.63,13.65) higher invasive potential than P69 cells. Phage display biopanning of LNCaP cells versus C4-2 cells in vitro using 4 separate techniques repeatedly identified the same peptide in support of minimal cell surface changes associated with the ability of C4-2 cells to metastasize to bone. As integrins are vital to cell adhesion and migration, we examined the integrin subunit expression in the prostate cell lines. The expression of integrin subunits is much higher in the nontumorigenic cell line, P69, whereas the differences in integrin expression between LNCaP and C4-2 are negligible. Only alpha(2) and beta(5) integrin subunits increase from LNCaP to C4-2. Given that C4-2 cells spontaneously metastasize to bone in vivo and LNCaP cells do not, these studies imply that the ability of a metastatic prostate cancer cell to colonize the bone is not completely dependent upon the ability of the cancer cell to adhere to either osteoblastic cells or to the bone marrow endothelial cell lining. Therefore, the initial interaction between the bone endothelium or stroma and prostate cells is not accurately referred to as a tropic or homing response. The invasion assay results indicate that the invasive potential of the cell more accurately reflects the bone colonizing potential of a prostate cancer cell. It is likely that bidirectional paracrine interactions, subsequent to marrow adhesion, between prostate cancer cells and the bone microenvironment are what determine the successful colonization of the bone by prostate cancer cells. Further, functional changes in surface proteins that are involved in invasion are likely to occur without major changes in levels of cell surface protein expression. Functional integrin association, substratum usage and outside in signaling are more likely to predict metastatic behavior.     

Direct and indirect contribution of bone marrow‐derived cells to cancer

Stromal‐epithelial interactions may control the growth and initiation of cancers. Here, we not only test the hypothesis that bone marrow‐derived cells may effect development of cancers arising from other tissue cells by forming tumor stroma but also that sarcomas may arise by transformation of stem cells from the bone marrow and epithelial cancers may arise by transdifferentiation of bone marrow stem cells to epithelial cancers. Lethally irradiated female FVB/N mice were restored with bone marrow (BM) transplants from a male transgenic mouse carrying the polyoma middle T‐oncoprotein under the control of the mouse mammary tumor virus promoter (MMTV‐PyMT) and followed for development of lesions. All of 8 lethally irradiated female FVB/N recipient mice, restored with BM transplants from a male MMTV‐PyMT transgenic mouse, developed Y‐chromosome negative (Y−) cancers of various organs surrounded by Y+ stroma. One of the female FVB/N recipient mice also developed fibrosarcoma and 1, a diploid breast adenocarcinoma containing Y chromosomes. In contrast, only 1 of 12 control female mice restored with normal male BM developed a tumor (lymphoma) during the same time period. These results indicate not only that the transgenic BM‐derived stromal cells may indirectly contribute to development of tumors in recipient mice but also that sarcomas may arise by transformation of BM stem cells and that breast cancers arise by transdifferentiation of BM stem cells, presumably by mesenchymal‐epithelial transition.     

Crucial contribution of GPR56/ADGRG1, expressed by breast cancer cells,to bone metastasis formation

From a mouse triple-negative breast cancer cell line, 4T1, we previously established 4T1.3 clone with a high capacity to metastasize to bone after its orthotopic injection into mammary fat pad of immunocompetent mice. Subsequent analysis demonstrated that the interaction between cancer cells and fibroblasts in a bone cavity was crucial for bone metastasis focus formation arising from orthotopic injection of 4T1.3 cells. Here, we demonstrated that a member of the adhesion G-protein–coupled receptor (ADGR) family, G-protein–coupled receptor 56 (GPR56)/adhesion G-protein–coupled receptor G1 (ADGRG1), was expressed selectively in 4T1.3 grown in a bone cavity but not under in vitro conditions. Moreover, fibroblasts present in bone metastasis sites expressed type III collagen, a ligand for GPR56/ADGRG1. Consistently, GPR56/ADGRG1 proteins were detected in tumor cells in bone metastasis foci of human breast cancer patients. Deletion of GPR56/ADGRG1 from 4T1.3 cells reduced markedly intraosseous tumor formation upon their intraosseous injection. Conversely, intraosseous injection of GPR56/ADGRG1-transduced 4T1, TS/A (mouse breast cancer cell line), or MDA-MB-231 (human breast cancer cell line) exhibited enhanced intraosseous tumor formation. Furthermore, we proved that the cleavage at the extracellular region was indispensable for GPR56/ADGRG1-induced increase in breast cancer cell growth upon its intraosseous injection. Finally, inducible suppression of Gpr56/Adgrg1 gene expression in 4T1.3 cells attenuated bone metastasis formation with few effects on primary tumor formation in the spontaneous breast cancer bone metastasis model. Altogether, GPR56/ADGRG1 can be a novel target molecule to develop a strategy to prevent and/or treat breast cancer metastasis to bone.     

Expression of Preprotachykinin-I （PPT-I）, Neurokinin-1 （NK-1） and Neurokinin-2 （NK-2） in Breast Cancer Cells Improves Tumor Cell Survival in Bone Marrow in the Early Stage of Metastasis

OBJECTIVE To study the potential relationship between the expression of PPT-I, NK-1, NK2 and the development of breast cancer cells in bone marrow stroma and to provide evidence of potential molecular mechanisms of breast cancer patients. of bone metastasis in early stage METHODS The cocultures of breast cancer cell line T-47D and marrow-derived mesenchymal stem cells （MSC） were established with equal numbers. T-47D cells were separated from the coculture system at 48 h and 96 h after coculture by MACS magnetic cell sorting （MicroBeads）. The expression of PPT-I, NK-1, NK-2 in T-47D was then examined before and after coculture by real-time PCR and by Western blot. Alterations in cellular ultrastructure of T-47D cells were detected before and after coculture under electron microscope. Finally, changes in cell cycle distribution were examined by flow cytometry, and growth curves from before and after coculture were drawn and analyzed. RESULTS Following coculture of T-47D and MSC, the expression of PPT-I mRNA and protein was significantly upregulated, while the expression of NK-1 and NK-2 mRNA and protein was greatly downregulated. The analysis of cell cycle distribution by flow cytometry showed that the proportion of T-47D during S phase was increased, and the duration of the G2/M phase was sharply decreased. Under electron microscope, we observed that the synthesis of hereditary material was increased, but the hepatin granules were shown prominent stacking in T-47D cells. These results suggest that although the synthesis of DNA was increased, the proliferation of cells was inhibited after coculture. The cell growth curve confirmed the findings from the observation under the electron microscope and flow cytometry. CONCLUSION Tumor cells could survive through the upregulation in expression of preprotachykinin-I gene during early bone metastasis in breast cancer. The phenomenon of growth suppression in breast cancer cells after coculture in the current study could be induced by downregulation in expression of NK-1 and NK-2.     

Increased Dickkopf-1 expression in breast cancer bone metastases

The aim of this study was to determine whether Dickkopf-1 (Dkk-1) expression in breast cancer was associated with bone metastases. We first analysed Dkk-1 expression by human breast cancer cell lines that induce osteolytic or osteoblastic lesions in animals. Dickkopf-1 levels were then measured in the bone marrow aspirates of hind limbs from eight NMRI mice inoculated with breast cancer cells that induced bone metastases and 11 age-matched non-inoculated control animals. Finally, Dkk-1 was measured in the serum of 17 women with breast cancer in complete remission, 19 women with breast cancer and bone metastases, 16 women with breast cancer and metastases at non-bone sites and 16 healthy women. Only breast cancer cells that induce osteolytic lesions in animals produced Dkk-1. There was a six-fold increase in Dkk-1 levels in the bone marrow from animals inoculated with MDA-B02 cells when compared with that of control non-inoculated animals (P=0.003). Median Dkk-1 levels in the serum of patients with breast cancer and bone metastases were significantly higher than levels of patients in complete remission (P=0.016), patients with breast cancer having metastases at non-bone sites (P<0.0001) and healthy women (P=0.047), although there was a large overlap in individual levels between the different groups. In conclusion, Dkk-1 is secreted by osteolytic human breast cancer cells lines and increased circulating levels are associated with the presence of bone metastases in patients with breast cancer. Measurements of circulating Dkk-1 levels may be useful for the clinical investigation of patients with breast cancer and bone metastases.     

Evaluating the link between stem cells and breast cancer

Mammary stem cells have recently been identified and purified on the basis of surface antigens and transplantation assays. In addition, recent reports have identified a small sub-population of highly tumorigenic cells within primary and metastatic breast tumors and in a number of breast cancer cell lines. This suggests that, similarly to its normal physiological counterpart, a cancer stem cell may be at the origin of breast cancer. These observations have dramatic biological and clinical implications, as they dictate a revision of our understanding of breast cancer and of our therapeutic strategies. The aim of this article is to review recent data regarding normal mammary epithelial stem cells and evidence in support of the cancer stem cell hypothesis in the breast, and to provide further insight into how taking this subpopulation of cells into account may affect the way we treat epithelial cancers in the future.     

Characterization of a rat model with site-specific bone metastasis induced by MDA-MB-231 breast cancer cells and its application to the effects of an antibody against bone sialoprotein

Metastasis into the skeleton is a serious complication of certain neoplastic diseases such as breast, prostate and lung cancer, but the reasons for this osteotropism are poorly understood. Our aim was to establish a physiologically relevant animal model that is characterized by osteolytic lesions confined to the hind leg of nude rats. For this purpose, we injected 1x10(5) MDA-MB-231 human breast cancer cells transfected with GFP into the superficial epigastric artery, which is an anastomosing vessel between the femoral and iliac arteries. As assessed with the aid of X-rays, computed tomography and immunohistochemisty, osteolytic lesions occurred exclusively in the femur, tibia and fibula of the animals. The tumor take rate was 93% in a series of 96 rats and the increase in lesion size was observed up to 110 days after tumor cell inoculation. When applying this animal model to the effects of an antibody against bone sialoprotein (BSP), a significantly reduced osteolytic lesion size was observed after preincubation of cells (2 hr, 600 microg/ml anti-BSP) prior to intra-arterial tumor cell injection resulting in 19 T/C% at day 60 after tumor implantation (p < 0.05). In addition, the osteolytic lesion size was also significantly reduced after s.c. treatment of the animals with the antibody (20 mg/kg anti-BSPx3 within 5 days after tumor implantation), resulting in 30 T/C% at day 60 after tumor cell implantation (p < 0.05). In conclusion, the novel rat model for site-specific osteolytic lesions provides in vivo evidence that preincubation of MDA-MB-231GFP cells and treatment of rats after tumor implantation with an antibody against BSP significantly reduces the size of lytic lesions in bone.     

乳腺癌骨转移疼痛的综合治疗

目的　探讨缓解乳腺癌骨转移疼痛 ,恢复患者活动能力的方法。方法　 31例乳腺癌骨转移患者采用以CMFP或CAFP方案化疗为主 ,辅以放射性同位素或双磷酸盐类药物综合治疗 ,观察治疗后疼痛缓解、活动能力恢复及骨外转移灶的变化情况。结果　全组骨痛缓解率为 87.1 % (2 7/ 31 ) ,功能活动恢复 85 .7% (6/ 7) ,骨外转移灶的有效率为 67.9% (1 9/ 2 8)。结论　以化疗为主的综合治疗 ,不仅能较好地控制骨外转移灶的发展 ,而且能显著地缓解骨痛 ,恢复患者的活动能力     

乳腺癌研究及治疗新靶点—乳腺癌干细胞的研究进展

随着人们对乳腺癌发生、发展机制的深入研究,乳腺癌干细胞日益受到研究者们的重视,研究表明,乳腺癌干细胞是一群未分化、具有自我更新及多系分化潜能的细胞。这些细胞具有化疗、放疗及缺氧抵抗性,同时具有高致瘤性、高侵袭转移性和在乳腺癌的发生﹑发展乃至转移﹑复发中起着极其重要作用。深入研究乳腺癌干细胞相关信号转导通路和微环境的调控,为临床靶向治疗乳腺癌具有重要的指导意义。因此,本文对乳腺癌干细胞在乳腺癌研究及治疗中的最新进展作一综述。     

Efficacy of YM-175, a new bisphosphonate,in the treatment of metastatic bone tumor from breast cancer and its effect on scintigraphy

Background Bisphosphonates are powerful inhibitors of osteoclast-mediated bone resorption. They are effective in the treatment of Paget's disease of the bone, tumor-associated hypercalcemia, and osteoporosis. They are also used to treat metastatic bone disease. YM-175 is a new highly potent bisphosphonate. Bisphosphonates are also used as radiopharmaceuticals in bone scintigraphy. The data remain unclear as to whether or not the administration of large amounts of bisphosphonate interferes with the bone scintigraphy process. Methods We have treated 8 patients with bone metastases from breast cancer with 10 mg IV, once a week for 5 weeks. The monitoring of bone pain, laboratory analysis with bone metabolic markers, and bone imaging including x-ray and bone scintigraphy, was performed for 8 weeks. A quantitative method was employed to evaluate serial bone scintigraphy. Results Bone pain improved in 5 out of 8 cases at 2 and 4 weeks post-treatment without serious adverse effects, but the duration of pain relief was short. Markers of osteoclast activity were decreased significantly to a minimum at 2 weeks. No significant changes were shown in markers of osteoblast activity or in serum calcium levels. Intact parathyroid hormone (PTH) was elevated at 2 and 4 weeks. It appears that YM-175 suppressed osteoclast activity, however, its effect was negated by a PTH elevation response. No changes were detected in either x-ray findings or serial bone scintigraphy by use of visual images and quantitative methods. Conclusion YM-175, a new bisphosphonate, was a safe and promising drug for the treatment of metastatic bone pain from breast cancer. Osteoclast activity was suppressed by bisphosphonate treatment, but, the PTH response negated the osteoclast suppression. Furthermore, YM-175 treatment did not alter bone scintigraphic images.