Ken Shintani

Decorin suppresses bone metastasis in a breast cancer cell line.

Decorin, the prototype of an expanding family of small leucine-rich proteoglycans, is involved in a number of cellular processes including matrix assembly, fibrillogenesis and the control of cell proliferation. In this study, we investigated the role of decorin in suppressing tumor aggressiveness and bone metastases. We used a metastatic breast cancer cell line, MDA-MB-231, to show that decorin causes marked growth suppression bothin vitro and in vivo. A cytomegaloviral vector containing the decorin transgene caused greatly reduced cell growth, motility and observed metastases. Bone metastases were decreased by >90% upon decorin transfection. These results demonstrate a novel role for decorin in the reduction or prevention of tumor metastases in this breast cancer model and could eventually lead to improved therapies for metastatic breast cancer.

Expression of hypoxia-inducible factor (HIF)-1α as a biomarker of outcome in soft-tissue sarcomas

Hypoxia-inducible factor (HIF)-1α is a transcription factor that supports the adaptation of human cancer cells to hypoxia and tumor growth and progression. The overexpression of HIF-1α protein has been reported to be associated with a worse prognosis in various cancers. However, the expression of HIF-1α in soft-tissue sarcomas has not yet been characterized. The expression of HIF-1α protein was immunohistochemically determined in 49 specimens of soft-tissue sarcomas including malignant fibrous histiocytoma (29 patients), synovial sarcoma (12 patients), leiomyosarcoma (four patients), and malignant peripheral nerve sheath tumors (four patients). The 49 samples consisted of 40 primary lesions and nine local recurrences. An immunohistochemical analysis showed the nuclear accumulation of HIF-1α protein in 35 (71.4%) samples. The expression of HIF-1α was negative in 14 (28.6%) cases, weak in nine (18.4%), moderate in 17 (35.4%), and strong in nine (18.4%). The patients with a strong or moderate expression of HIF-1α had a significantly shorter overall survival rate in comparison with those with a weak or negative expression in a univariate analysis (P = 0.029; log-rank test) and multivariate analysis (P = 0.018). This is the first report that demonstrated an overexpression of HIF-1α protein to be an independent prognostic factor for soft-tissue sarcomas.

iNOS-dependent DNA damage in patients with malignant fibrous histiocytoma in relation to prognosis

Malignant fibrous histiocytoma (MFH) is one of the most common soft tissue sarcomas. MFH has been proposed to be a lesion accompanied with inflammatory responses. During chronic inflammation, reactive nitrogen and oxygen species generated from inflammatory cells are considered to participate in carcinogenesis by causing DNA damage. 8‐nitroguanine is a mutagenic nitrative DNA lesion formed during chronic inflammation. We examined whether nitrative DNA damage is related to the prognosis of MFH patients. We performed immunohistochemical analyses to examine the distribution of DNA damage and the expression of inflammation‐related molecules including inducible nitric oxide synthase (iNOS), nuclear factor‐κB (NF‐κB), and cyclooxygenase‐2 (COX‐2) in clinical specimens from 25 patients with MFH. We also analyzed the correlation of DNA damage or the expression of these genes with the prognosis of MFH patients. Immunohistochemical staining revealed that the formation of 8‐nitroguanine and 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine (8‐oxodG), an oxidative DNA lesion, occurred to a much greater extent in MFH tissue specimens from deceased patients than in live patients. iNOS, NF‐κB and COX‐2 were colocalized with 8‐nitroguanine in MFH tissues. It is noteworthy that the statistical analysis using the Kaplan‐Meier method demonstrated strong 8‐nitroguanine staining to be associated with a poor prognosis. In conclusion, 8‐nitroguanine appears to participate in not only the initiation and promotion of MFH, but also in the progression of MFH, and could therefore be used as a promising biomarker to evaluate the prognosis of cancer patients. (Cancer Sci 2007; 98: 163–168)

Clinical Outcome of a Novel Photodynamic Therapy Technique Using Acridine Orange for Synovial Sarcomas

Abstract Synovial sarcoma (SS) is one of common malignant soft-tissue tumors and is encountered most commonly in children and young adults. It frequently involves or invades major neurovascular structures and bones, and its local recurrence rate after simple resection has been reported to be as high as up to 80%. Because major nerves and vessels, as well as an adequate amount of bone, must be preserved to restore excellent limb function in cases of SS, a surgical technique entailing a low risk of local recurrence is needed. Based on the findings of recent experimental studies conducted by us using a mouse osteosarcoma model, we developed a novel therapeutic technique for SS, consisting of reduction surgery followed by photodynamic therapy using acridine orange (AO-PDT), with or without X-ray irradiation at 5 Gy. A preliminary study revealed that low-dose X-rays also excite AO like photons. After an initial study on cell cultures, this novel technique was applied to six cases of SS. A follow-up of the subjects to determine the clinical outcome revealed that none of the cases treated by AO-PDT, including the four cases treated by additional 5 Gy irradiation and the two cases not receiving any radiation, showed any evidence of recurrence or local/systemic complications during the follow-up period of 19–51 months after the surgery. Therefore, we believe that AO-PDT with 5 Gy irradiation may be an excellent novel therapeutic modality with reduction surgery to salvage excellent limb function in SS involving major nerves and vessels or bones.

Extracorporeal Photodynamic Image Detection of Mouse Osteosarcoma in Soft Tissues Utilizing Fluorovisualization Effect of Acridine Orange

Various imaging methods have been employed for the extracorporeal detection of malignant tumors in the human body, such as scintigraphy and PET; however, none is sufficiently accurate and all are also very expensive. To resolve these issues, we attempted to develop a new imaging technique of photodynamic diagnosis (PDD) with acridine orange (AO). AO has the ability to rapidly and specifically accumulate in malignant tumors and emit brilliant green fluorescence after blue light excitation. In this study, we investigated the feasibility of PDD utilizing the fluorovisualization effect of AO, for the extracorporeal detection of mouse osteosarcoma inoculated into the soft tissues. At 2 h after intravenous administration of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 mg/kg AO, the tumor and the surrounding normal tissues were illuminated by blue light. The visual fluorescence contrast and ratio (X) of the difference in fluorescence intensity between the tumor and the surrounding normal tissues were evaluated using a high-resolution digital camera equipped with an absorption filter. In addition, the fluorescence contrast was also detected sequentially at 0.5, 1, 2, 3, 6 and 12 h after intravenous administration of AO at 1.0 mg/kg. The results revealed that the optimal condition for clear detection of the tumor was evaluation 2 h after intravenous injection of AO at 0.1 mg/kg, because it provided the best visual contrast on the digital images, and the fluorescence intensity as well as the value of X were higher as compared to the values under other conditions of dose and timing. Based on the results of an acute toxicity study of AO, the estimated LD50 of this substance following intravenous administration was 27.30 mg/kg. In conclusion, we believe that PDD using AO administered intravenously may be feasible for the detection of human musculoskeletal sarcomas in the soft tissues at extremities, and this technique might be a less invasive, less expensive, quicker and more accurate imaging modality than other previously reported imaging methods for this purpose.

Histiocytic Osteolysis Secondary to Hyperbilirubinaemia: A Case Report

A 6-year-old boy with Alagille syndrome, characterised by marked hyperbilirubinaemia, presented with malunion of a pathological fracture of the femur with local bone atrophy and insufficient callus formation. During corrective osteotomy, it was noted that the femur was stained dark green, suggestive of bilirubin deposition. Histology of the resected bone revealed the presence of many histiocytes and osteoclast-like multinucleate giant cells containing bilirubin particles in the cytoplasm causing bone resorption. These findings suggest that bilirubin may activate macrophages to form osteoclast-like multinucleate giant cells, resulting in histiocytic osteolysis.