Hiroshi Urakawa

Inhibition of hyaluronan synthesis in breast cancer cells by 4‐methylumbelliferone suppresses tumorigenicity in vitro and metastatic lesions of bone in vivo

Hyaluronan (HA) has been shown to play crucial roles in the tumorigenicity of malignant tumors. Previous studies demonstrated that inhibition of HA suppressed the tumorigenicity of various malignant tumors including breast cancer. 4‐methylumbelliferone (MU) has been reported to inhibit HA synthesis in several cell types. However, few studies have focused on the effects of HA inhibition in breast cancer cells by MU, nor the effects on bone metastasis. We hypothesized that MU would suppress the progression of bone metastasis via inhibition of HA synthesis. Here, we investigated the effects of MU on HA expression in MDA‐MB‐231 breast cancer cell line in addition to their tumorigenicity in vitro and in vivo. HAS2 mRNA expression was downregulated after 6 and 24 hr treatment with MU. Quantitative analysis of HA revealed that MU significantly inhibited the intracellular and cell surface HA. MU significantly inhibited cell growth and induced apoptosis as determined by cell proliferation and TUNEL assays, respectively. Phosphorylation of Akt was suppressed after 12 and 24 hr treatment with MU. MU treatment also inhibited cell motility as well as cell invasiveness. MU also inhibited cell growth and motility in murine fibroblast cell line NIH3T3. In vivo, administration of MU inhibited the expansion of osteolytic lesions on soft X‐rays in mouse breast cancer xenograft models. HA accumulation in bone metastatic lesions was perturbed peripherally. These data suggest that MU might be a therapeutic candidate for bone metastasis of breast cancer via suppression of HA synthesis and accumulation.

Inhibition of hyaluronan retention by 4-methylumbelliferone suppresses osteosarcoma cells in vitro and lung metastasis in vivo.

Background:Hyaluronan (HA) plays crucial roles in the tumourigenicity of many types of malignant tumours. 4-Methylumbelliferone (MU) is an inhibitor of HA synthesis. Several studies have shown its inhibitory effects on malignant tumours; however, none have focused on its effects on osteosarcoma.Methods:We investigated the effects of MU on HA accumulation and tumourigenicity of highly metastatic murine osteosarcoma cells (LM8) that have HA-rich cell-associated matrix, and human osteosarcoma cell lines (MG-63 and HOS).Results:In vitro, MU inhibited HA retention, thereby reducing the formation of functional cell-associated matrices, and also inhibited cell proliferation, migration, and invasion. Akt phosphorylation was suppressed by MU (1.0u2009mM). In vivo, although MU showed only a mild inhibitory effect on the growth of the primary tumour, it markedly inhibited (75% reduction) the development of lung metastasis. Hyaluronan retention in the periphery of the primary tumour was markedly suppressed by MU.Conclusion:These findings suggested that MU suppressed HA retention and cell-associated matrix formation in osteosarcoma cells, resulting in a reduction of tumourigenicity, including lung metastasis. 4-Methylumbelliferone is a promising therapeutic agent targeting both primary tumours and distant metastasis of osteosarcoma, possibly via suppression of HA retention.

Suppression of Hyaluronan Synthesis Alleviates Inflammatory Responses in Murine Arthritis and in Human Rheumatoid Synovial Fibroblasts

OBJECTIVEnTo clarify the roles of hyaluronan (HA) in joint inflammation and the process of joint destruction, using 4-methylumbelliferone (4-MU), an inhibitor of HA synthesis, in a mouse model of collagen-induced arthritis (CIA) and in a monolayer culture of fibroblast-like synoviocytes (FLS) derived from patients with rheumatoid arthritis.nnnMETHODSnDAB/1J mice were immunized with type II collagen. The effects of 4-MU were evaluated by the physiologic arthritis score, paw swelling, the histologic arthritis score, and expression of matrix metalloproteinase 3 (MMP-3) and MMP-13 in chondrocytes and synovial tissue. In vitro, the effect of 4-MU on messenger RNA and protein expression of MMP-1 and MMP-3 was determined. The effects of 4-MU on HA deposition and on serum/medium concentrations of HA were analyzed using biotinylated HA binding protein staining and an HA binding assay, respectively.nnnRESULTSnTreatment with 4-MU in mice with CIA dramatically decreased the severity of arthritis (based on the arthritis score), paw thickness, and histopathologic changes. MMP-3 and MMP-13 expression in chondrocytes and synovial cells was significantly inhibited by 4-MU in vivo. Treatment with 4-MU also inhibited MMP-1 and MMP-3 expression in tumor necrosis factor α-stimulated FLS, in a dose-dependent manner. The 4-MU-induced decreases in the serum HA concentration in mice with CIA and in medium and pericellular HA concentrations in cultured FLS support the contention that the inhibitory mechanism of 4-MU is mediated by HA suppression.nnnCONCLUSIONnReduced disease activity induced by 4-MU in mice with CIA revealed HA to be a crucial regulator in the course of arthritis. Therefore, 4-MU is a potential therapeutic agent in arthritis, and its inhibitory mechanism is possibly mediated by suppression of HA synthesis.

Cyclooxygenase-2 Overexpression Predicts Poor Survival in Patients with High-grade Extremity Osteosarcoma: A Pilot Study

AbstractSeveral lines of evidence suggest cyclooxygenase-2 (COX-2) overexpression may be a causal factor for tumor growth and metastasis. However, there is no evidence COX-2 expression in a primary tumor correlates with clinical outcome of osteosarcoma. We examined expression levels of COX-2 immunohistochemically in 51 patients with extremity osteosarcoma who completed standard therapy and obtained complete initial regression of the tumor. Correlation of the positivity of staining with prognosis was analyzed. COX-2 was expressed in most of the cases. We found no correlation between COX-2 staining intensity and variables such as gender, age, anatomic site, necrosis after chemotherapy, and surgical stage. Strong COX-2 expression was associated with low metastasis-free survival. Age older than 20xa0years and strong COX-2 expression independently predicted increased risk of metastasis. Among seven patients with resectable lung metastasis, all three with greater COX-2 expression in the metastatic lesion than that in a primary site died of the disease. Our preliminary data suggest COX-2 overexpression in the primary tumor correlates with the occurrence of distant metastasis in patients with osteosarcoma and also may affect postmetastatic survival.n Level of Evidence: Level IV, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Prognostic value of indoleamine 2,3-dioxygenase expression in high grade osteosarcoma

Indoleamine 2,3-dioxygenase (IDO) is a tryptophan-catabolising enzyme inducing immune tolerance. Some reports have noted a clinical correlation between IDO expression and outcome in some malignant tumors. This study aimed to investigate IDO expression as related to prognosis in osteosarcoma. IDO expression was immunohistochemically scored as five grades. IDO was expressed in most of the cases. Univariate analysis revealed no significant correlation between IDO staining intensity and various variables including sex, age, anatomical site, chemotherapy regimen, necrosis after chemotherapy, and surgical stage. Patients with high IDO expression had significantly lower metastasis-free survival (Pxa0=xa00.016) and overall survival (Pxa0=xa00.005). On univariate analysis, age over 20xa0years and high IDO expression were found to be independent risk factors of lower overall survival and metastasis-free survival. On multivariate analysis, there was no significant correlation between high IDO expression and metastasis-free survival (Pxa0=xa00.070) and overall survival (Pxa0=xa00.066). The immune tolerance mediated through IDO may have an important role in the tumorigenesis of osteosarcoma and may exert an impact on the clinical outcome, and thus may lend itself as a therapeutic target of immunotherapy for osteosarcoma.

Therapeutic potential of hyaluronan oligosaccharides for bone metastasis of breast cancer

Hyaluronan (HA) oligosaccharides were reported to have suppressive effects on various malignant tumors via disruption of receptor HA interactions. However, no studies have focused on the effects of HA oligosaccharides on bone metastasis of breast cancer. In this study, we clarified the effective size of HA oligosaccharides required to inhibit cell growth in the highly invasive breast cancer cell line, MDA‐MB‐231 cells. Based on the results of cell growth assay, we subsequently analyzed the effects of HA tetrasaccharides, HA decasaccharides, and high molecular weight HA on the other breast cancer cell behaviors in vitro and breast cancer bone metastasis in vivo. HA decasaccharides significantly inhibited cell growth, motility, and invasion, whereas tetrasaccharides did not. HAS2 mRNA expression was altered after the treatment with both tetrasaccharides and decasaccharides. Phosphorylation of Akt was suppressed after 1u2009h treatment with HA decasaccharides, and the effect was partially reversed by anti‐CD44 monoclonal antibody. In vivo, local application of HA decasaccharides inhibited the expansion of osteolytic lesions in tibia on soft X‐rays using mouse bone metastasis model of breast cancer. Histological analysis revealed HA accumulation in bone metastatic lesions was perturbed by decasaccharides. These results suggest that HA oligosaccharides suppressed progression of bone metastasis in breast cancer via interruption of endogenous HA–CD44 interaction, and as such, can be a novel therapeutic candidate to limit bone metastasis of breast cancer.

Versican V1 isoform regulates cell-associated matrix formation and cell behavior differentially from aggrecan in Swarm rat chondrosarcoma cells

Versican, a large chondroitin sulfate proteoglycan that binds hyaluronan and is composed of large extracellular matrix aggregates, has been shown to correlate with tumor progression. No studies have examined the roles of versican in chondrosarcoma nor compared them to those of aggrecan. In clinical specimens of human chondromatous tumors, versican expression was significantly increased in malignant tumors, moreover, as the tumor grade increased. To clarify the roles of versican in chondrosarcoma, versican splicing variant 1, variant 3 or only GFP was stably transfected to Swarm rat chondrosarcoma cells with Trap‐In System. Forced expression of versican V1 isoform in Swarm rat chondrosarcoma cells induced a marked increase of cell‐associated matrix compared to V3‐, GFP‐ transfected or RCS cells. Versican was immunolocalized in a fashion similar to that of hyaluronan and more diffusively than aggrecan. Anchor‐dependent and ‐independent growth was not affected by versican isoform expression, whereas cell motility and migration were significantly enhanced by V1 isoform transfection. Tumors formed in vivo with V1‐transfected cells exhibited more myxomatous area and included more spindle shaped cells. These results support the concept that versican has the capacity to form more extensive cell‐associated matrix than aggrecan, and the prominent matrix formation alters the cell behavior of chondrosarcoma more aggressively. These observations suggest that versican expression may serve as a marker of tumor grade determination in chondrosarcoma and possibly help to decide on therapeutic targets in higher grades of chondrosarcoma.

Hyaluronan synthesis inhibitor supplements the inhibitory effects of zoledronic acid on bone metastasis of lung cancer

Hyaluronan is known to have pivotal roles in the growth, migration and invasion of malignant tumors. Bone metastases are critical lesions greatly impairing the quality of patients with malignancies. We investigated whether hyaluronan synthesis inhibitor supplements the inhibitory effects of zoledronic acid, which is a conventional therapeutic agent for bone metastasis. We examined the effects of methylumbelliferone, an inhibitor of hyaluronan synthesis and/or ZA on the tumorigenicity of one murine lung carcinoma and two human (A549, SK-MES-1) lung cancer cell lines in vitro. The interaction between methylumbelliferone and zoledronic acid was analyzed using Calcucyn software. With a murine bone metastasis model of lung cancer in vivo, we investigated the inhibitory effects and interaction of the two drugs on the progression of metastatic bone lesions. Methylumbelliferone or zoledronic acid treatment individually suppressed proliferation, migration and invasion of 3 cell lines, and combination treatment showed synergistic effects. Although methylumbelliferone as a single agent did not enhance apoptotic activity, it showed additive effects on apoptotic activity to those of zoledronic acid. Co-localization of CD44 and ezrin, which might be a pathway of hyaluronan signaling, was abrogated by methylumbelliferone treatment. Combination therapy showed additive inhibitory effects on metastatic bone lesions in vivo, which paralleled the inhibition of hyaluronan accumulation by methylumbelliferone, and inhibition of osteoclastogenesis. Although the detailed mechanisms underlying the synergistic or additive inhibitory effects of these two drugs should be further analyzed, inhibition of hyaluronan synthesis by methylumbelliferone is a promising novel therapeutic candidate for bone metastasis of lung cancer in addition to zoledronic acid.

Metastasis of osteosarcoma to stomach made clinically evident by hematemesis: a case report

BackgroundGastric metastasis from osteosarcoma is very rare and its clinical features are not well recognized.Case presentationA 73-year-old man was diagnosed with osteosarcoma and treated with four cycles of preoperative chemotherapy with ifosfamide and doxorubicin followed by wide resection. Two cycles of postoperative chemotherapy with ifosfamide and doxorubicin and ten cycles of chemotherapy with carboplatin and etoposide were administered. Eleven months after the surgery, he vomited fresh blood. Unusual progression of anemia was observed with the hematemesis. A biopsy was performed by gastrointestinal endoscopy, and the stomach tumor was diagnosed as metastasis of osteosarcoma.ConclusionsEven though gastric metastasis from osteosarcoma is very rare, all three previous reports and our case showed the presence of ulcer on the surface of the gastric lesion. We should consider the possibility of gastric metastasis in patients with osteosarcoma in whom progression of anemia or gastric hemorrhage is observed.

Glanzmann thrombasthenia detected because of knee hemarthrosis: a case report.

Glanzmann thrombasthenia (GT) is a rare bleeding syndrome, which is characterized by a lack of platelet aggregation. We report a case of GT that was first detected because of the presence of hemarthrosis of the knee. The patient was an 8-year-old boy who presented with a sudden, painful left knee after outdoor games. Till the first visit to our hospital, he had not been diagnosed with GT despite a history of bleeding tendency, notably purpura in areas of easy bruising and prolonged bleeding time after abrasions and insect stings. Gross blood was found at arthrocentesis of the left knee, and GT was diagnosed on the basis of prolonged bleeding time, lack of platelet aggregation with ADP and collagen, and absence of platelet surface glycoprotein IIb/IIIa. Although hemarthrosis of GT is rare, this disease should be considered in a patient with bleeding tendency and prolonged bleeding time.