Hypoxia-enhanced derivation of iPSCs from human dental pulp cells

Hypoxia enhances the reprogramming efficiency of human dermal fibroblasts to become induced pluripotent stem cells (iPSCs). Because we showed previously that hypoxia facilitates the isolation and maintenance of human dental pulp cells (DPCs), we examined here whether it promotes the reprogramming of DPCs to become iPSCs. Unlike dermal fibroblasts, early and transient hypoxia (3% O2) induced the transition of DPCs to iPSCs by 3.3- to 5.1-fold compared with normoxia (21% O2). The resulting iPSCs closely resembled embryonic stem cells as well as iPSCs generated in normoxia, as judged by morphology and expression of stem cell markers. However, sustained hypoxia strongly inhibited the appearance of iPSC colonies and altered their morphology, and anti-oxidants failed to suppress this effect. Transient hypoxia increased the expression levels of NANOG and CDH1 and modulated the expression of numerous genes, including those encoding chemokines and their receptors. Therefore, we conclude that hypoxia, when optimized for cell type, is a simple and useful tool to enhance the reprogramming of somatic cells to become iPSCs.

Abstract 3320: Combined effect of zoledronic acid and telomerase-specific oncolytic virotherapy for human osteosarcoma cells

Osteosarcoma is the most frequent type of primary malignant bone tumor and common between the ages of 10 to 25. Based on preoperative and postoperative chemotherapy, the prognosis of osteosarcoma patients has improved. However, 30% of osteosarcoma patients who become refractory to chemotherapy still die from tumor or metastasis. We previously reported that telomerase-specific, replication-competent oncolytic adenovirus (Telomelysin, OBP-301), efficiently killed human bone and soft tissue sarcoma cells but not normal human somatic cells. Recently, third-generation bisphosphonates, zoledronic acid (ZOL), is widely used to inhibit bone destruction in metastatic bone tumor through induction of apoptosis in osteoclast cells in the clinical settings. Moreover, ZOL has been shown to induce the antitumor effect synergistically in combination with chemotherapeutic agents in human sarcoma cells. In this study, we investigated the combined antitumor effect of ZOL and OBP-301 in human osteosarcoma cells. Three human osteosarcoma cell lines, HOS, SaOS-2, U2OS, were used. We used XTT assay to examine the antitumor effect of ZOL and OBP-301 individually and combinatory on days 2, 3, 5 after treatment. ZOL was treated at concentration of 0 to 10μM, and OBP-301 was infected at multiplicity of infections (MOI) of 0 to 50 plaque forming units (PFU)/cell. Synergy between ZOL and OBP-301 was analyzed with the CalcuSyn software (BioSoft). XTT assay showed that treatment of ZOL or OBP-301 decreased the cell viability in a time- and dose-dependent manner. Combination treatment of ZOL and OBP-301 showed synergy and additive effects. After calculation of the half maximal (50%) inhibitory concentration (IC50) of ZOL and dose (ID50) of OBP-301 for each cell, cells were treated with ZOL and OBP-301 for 3 days at concentration of IC50 and ID50, respectively. Whole cell lysates were subjected to western blot analysis for the cleaved PARP (C-PARP) and PARP, LC3, p62 and β-actin. Western blot analysis revealed that ZOL induced apoptosis, which was confirmed by increasing of C- PARP, and OBP-301 induced not only apoptosis but also autophagy, which is confirmed by conversion of LC3- I to LC3- II and p62 down-regulation. Combination treatment showed increasing of these effects synergistically or additively in each cell. These results suggest that combination treatment of ZOL and OBP-301 is a promising antitumor strategy for patients with osteosarcomas. We are now planning to investigate the antitumor and bone-protective effects of combination treatment in an orthotopic xenograft tumor model using 3D-CT imaging system.

Citation Format: Yasuaki Yamakawa, Joe Hasei, Hiroshi Tazawa, Shuhei Osaki, Tsuyoshi Sasaki, Toshiyuki Kunisada, Aki Yoshida, Yasuo Urata, Toshifumi Ozaki, Toshiyoshi Fujiwara. Combined effect of zoledronic acid and telomerase-specific oncolytic virotherapy for human osteosarcoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3320. doi:10.1158/1538-7445.AM2013-3320

Abstract 584: Enhanced chemosensitivity of osteosarcoma cells by telomerase-specific oncolytic adenovirus in combination therapy

Osteosarcomas are the most common malignant bone tumors. Although the multi-agent chemotherapy has improved the long-term survival rate of osteosarcoma patients, some patients show a poor response to chemotherapy, leading to recurrence and poor prognosis. Therefore, the enhancement of chemosensitivity is required to cure patients with osteosarcomas. We recently developed a telomerase-specific replication-competent oncolytic adenovirus, Telomelysin (OBP-301), and confirmed the antitumor effect of OBP-301 in human osteosarcoma cells. A phase I clinical trial in US has also shown the safety of OBP-301 in cancer patients. In this study, we investigated whether OBP-301 enhances the antitumor effect of chemotherapeutic agents, doxorubicin and cisplatin, that are used for the treatment of osteosarcomas, and the molecular mechanism of chemotherapy- and OBP-301-mediated cell death pathway, autophagy and apoptosis, in human osteosarcoma cell lines. We used four human osteosarcoma cell lines, HOS, MNNG/HOS, 143B and SaOS2. OBP-301 is an attenuated adenovirus, in which the human telomerase reverse transcriptase (hTERT) promoter element drives expression of E1A and E1B genes, and causes tumor-selective lysis in a variety of human malignant tumor cells with high telomerase activity. OBP-301 infection enhanced the cytotoxic effect of chemotherapeutic agents and the calculation of combination index revealed the synergistic effects in all human osteosarcoma cell lines. To analyze the molecular mechanism in the synergistic effect induced by combination therapy, western blot analysis for apoptosis (PARP) and autophagy (LC3, p62) was performed. Combination of OBP-301 increased both apoptosis (the cleavage of PARP) and autophagy (conversion of LC3-I to LC3-II and p62 downregulation) in the chemotherapeutic agents-treated human osteosarcoma cells. In contrast, the replication of OBP-301 was not suppressed by chemotherapeutic agents. Moreover, combination therapy of chemotherapeutic agents with OBP-301 significantly suppressed tumor growth in a subcutaneous xenograft tumor model compared to monotherapy with chemotherapeutic agents or OBP-301. These results suggest that combination therapy of chemotherapeutic agents with OBP-301 provides a novel therapeutic strategy for human osteosarcomas.

Citation Format: Shuhei Osaki, Tsuyoshi Sasaki, Hiroshi Tazawa, Joe Hasei, Yasuaki Yamakawa, Yuuri Hashimoto, Toshiyuki Kunisada, Yasuo Urata, Toshifumi Ozaki, Toshiyoshi Fujiwara. Enhanced chemosensitivity of osteosarcoma cells by telomerase-specific oncolytic adenovirus in combination therapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 584. doi:10.1158/1538-7445.AM2013-584

[A case of synovial sarcoma with brain metastasis treated with surgical resection and stereotactic radiosurgery]

Synovial sarcomas compromise between 5 to 10% of all soft tissue sarcomas in adults. Synovial sarcoma commonly occurs in the vicinity of the large joints and cranial metastasis is rare. Here, we describe a case with intracranial metastases of a synovial sarcoma. A 41-year-old woman was admitted to our department with sensory aphasia. She had a history of a left inguinal synovial sarcoma and underwent surgery and chemotherapy for primary and metastatic lesions. Head MRI revealed three gadolinium-enhancing lesions in the left frontal, parietal and parietotemporal lobe. Gross total resection was achieved in the left parietotemporal lesion and pathological diagnosis was synovial sarcoma. Two weeks after surgery, she received cyber-knife radiosurgery and her neurological deficit was almost completely resolved. Intracranial metastatic synovial sarcoma is rare. Surgical resection and stereotaxic radiosurgery was very effective in the present case.

Dual programmed cell death pathways induced by p53 transactivation overcome resistance to oncolytic adenovirus in human osteosarcoma cells

Tumor suppressor p53 is a multifunctional transcription factor that regulates diverse cell fates, including apoptosis and autophagy in tumor biology. p53 overexpression enhances the antitumor activity of oncolytic adenoviruses; however, the molecular mechanism of this occurrence remains unclear. We previously developed a tumor-specific replication-competent oncolytic adenovirus, OBP-301, that kills human osteosarcoma cells, but some human osteosarcoma cells were OBP-301-resistant. In this study, we investigated the antitumor activity of a p53-expressing oncolytic adenovirus, OBP-702, and the molecular mechanism of the p53-mediated cell death pathway in OBP-301-resistant human osteosarcoma cells. The cytopathic activity of OBP-702 was examined in OBP-301-sensitive (U2OS and HOS) and OBP-301-resistant (SaOS-2 and MNNG/HOS) human osteosarcoma cells. The molecular mechanism in the OBP-702-mediated induction of two cell death pathways, apoptosis and autophagy, was investigated in OBP-301-resistant osteosarcoma cells. The antitumor effect of OBP-702 was further assessed using an orthotopic OBP-301-resistant MNNG/HOS osteosarcoma xenograft tumor model. OBP-702 suppressed the viability of OBP-301-sensitive and -resistant osteosarcoma cells more efficiently than OBP-301 or a replication-deficient p53-expressing adenovirus (Ad-p53). OBP-702 induced more profound apoptosis and autophagy when compared with OBP-301 or Ad-p53. E1A-mediated miR-93/106b upregulation induced p21 suppression, leading to p53-mediated apoptosis and autophagy in OBP-702-infected cells. p53 overexpression enhanced adenovirus-mediated autophagy through activation of damage-regulated autophagy modulator (DRAM). Moreover, OBP-702 suppressed tumor growth in an orthotopic OBP-301-resistant MNNG/HOS xenograft tumor model. These results suggest that OBP-702-mediated p53 transactivation is a promising antitumor strategy to induce dual apoptotic and autophagic cell death pathways via regulation of miRNA and DRAM in human osteosarcoma cells.

Surgical treatment for congenital kyphosis correction using both spinal navigation and a 3-dimensional model

An 11 year-old girl had 66 degrees of kyphosis in the thoracolumbar junction. For the purpose of planning for kyphosis correction, we created a 3-D, full-scale model of the spine and consulted spinal navigation. Three-dimensional models are generally used as tactile guides to verify the surgical approach and portray the anatomic relations specific to a given patient. We performed posterior fusion from Th10 to L3, and vertebral column resection of Th12 and L1. Screw entry points, directions, lengths and diameters were determined by reference to navigation. Both tools were useful in the bone resection. We could easily detect the posterior element to be resected using the 3D model. During the anterior bony resection, navigation helped us to check the disc level and anterior wall of the vertebrae, which were otherwise difficult to detect due to their depth in the surgical field. Thus, the combination of navigation and 3D models helped us to safely perform surgery for a patient with complex spinal deformity.

Statistical analysis of prognostic factors for survival in patients with spinal metastasis

There are a variety of treatment options for patients with spinal metastasis, and predicting prognosis is essential for selecting the proper treatment. The purpose of the present study was to identify the significant prognostic factors for the survival of patients with spinal metastasis. We retrospectively reviewed 143 patients with spinal metastasis. The median age was 61 years. Eleven factors reported previously were analyzed using the Cox proportional hazards model:gender, age, performance status, neurological deficits, pain, type of primary tumor, metastasis to major organs, previous chemotherapy, disease-free interval before spinal metastasis, multiple spinal metastases, and extra-spinal bone metastasis. The average survival of study patients after the first visit to our clinic was 22 months. Multivariate survival analysis demonstrated that type of primary tumor (hazard ratio [HR] = 6.80, p < 0.001), metastasis to major organs (HR = 2.01, p = 0.005), disease-free interval before spinal metastasis (HR = 1.77, p = 0.028), and extra-spinal bone metastasis (HR = 1.75, p = 0.017) were significant prognostic factors. Type of primary tumor was the most powerful prognostic factor. Other prognostic factors may differ among the types of primary tumor and may also be closely associated with primary disease activity. Further analysis of factors predicting prognosis should be conducted with respect to each type of primary tumor to help accurately predict prognosis.

Segmental pedicle screw fixation for a scoliosis patient with post-laminectomy and post-irradiation thoracic kyphoscoliosis of spinal astrocytoma

Spinal deformity is an important clinical manifestation after surgery for spinal cord tumors. One-third of patients who receive laminectomies and irradiation of the spinal column develop scoliosis, kyphosis, or kyphoscoliosis. Recent reports indicate good results after scoliosis surgery using segmental pedicle screws and a navigation system, but these reported studies have not included surgery for post-laminectomy kyphosis. Hooks and wires are ineffective in such patients who undergo laminectomy, and there are also high perioperative risks with insertion of pedicle screws because landmarks have been lost. Here, we report on the 5-year follow-up of a 13-year-old male patient with post-laminectomy and post-irradiation thoracic kyphoscoliosis after surgical treatment of spinal astrocytoma. Posterior segmental pedicle screw fixation was performed safely using a computer-assisted technique. The authors present the first case report for treatment of this condition using a navigation system.

Abstract 5651: p53-mediated apoptotic signaling overcomes the resistance to oncolytic adenovirus in human osteosarcoma cells

Despite major advances in the treatment of bone and soft tissue sarcomas, about one fourth of the patients show a poor response to conventional therapy, resulting in subsequent recurrence and leading to a poor prognosis. Therefore, the development of a novel therapeutic strategy is required to cure patients with bone and soft tissue sarcomas. We previously developed an oncolytic adenovirus, OBP-301, in which human telomerase reverse transcriptase (hTERT) gene promoter drives viral E1 gene for replication. OBP-301 induces tumor-specific oncolytic cell death in a telomerase-dependent manner. Recently, we revealed that OBP-301 shows cytopathic activity in human bone and soft tissue sarcoma cells. However, some human osteosarcoma cells were less sensitive to cytopathic activity of OBP-301. To enhance the cytopathic activity of OBP-301, we recently developed a novel telomerase-specific oncolytic adenovirus, OBP-702, which expresses tumor suppressor p53 gene. In this study, we investigated the antitumor effect of OBP-702 in OBP-301-sensitive (OST, HOS and U2OS) and OBP-301-resistant (MNNG/HOS and SaOS-2) human osteosarcoma cells. We compared the antitumor effects of OBP-702 and OBP-301 using XTT assay. The 50% inhibiting dose (ID50) value of OBP-702 and OBP-301 for each cell was calculated using cell viability data obtained on day 5 after virus infection. We further evaluated the expression of p53, p21 and cleaved poly (ADP-ribose) polymerase (PARP) proteins using western blot analysis in both OBP-301-sensitive and OBP-301-resistant osteosarcoma cells after infection with OBP-702 or Ad-p53, which is a p53-expressing replication-defective adenovirus. OBP-702 showed more cytopathic activity compared to OBP-301 in both OBP-301-sensitive and OBP-301-resistant osteosarcoma cells. The ID50 value of OBP-702 was lower than that of OBP-301 in all cell lines. OBP-702 induced not only oncolysis, but also apoptotic cell death with the cleavage of PARP. OBP-702 infection induced more profound p53 expression than Ad-p53. However, p53-downstream target p21 proteins were not activated by OBP-702. Taken together, we demonstrated that the p53-expressing oncolytic adenovirus OBP-702 has a much stronger antitumor effect than OBP-301 in human osteosarcoma cells. Oncolytic adenovirus-mediated p53 gene transduction would induce profound apoptosis through p53 upregulation without p21 activation, resulting in the enhancement of antitumor effect by OBP-301. OBP-702 would be a promising antitumor reagent for the treatment of OBP-301-resistant human osteosarcoma cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5651. doi:1538-7445.AM2012-5651

Reconstruction with ipsilateral fibula transfer with pasteurized bone after excision of bone sarcoma of the tibia

We report a technique of implantation of the ipsilateral vascularized fibula with pasteurized recycled bone after excision of tibia sarcoma in two cases. Plate and screws were used for osteosynthesis of the tibia or talus, vascularized fibula, and pasteurized bone. Microsurgery is not necessary for this reconstruction technique. Two patients who underwent this technique have obtained good functional results without tumor relapse 5 and 6 years after operation. The technique produced excellent results with regard to tibial reconstruction in these cases. We found it to be simple, speedy, safe, and a low cost technique by use of recycled bone.

Preclinical evaluation of telomerase-specific oncolytic virotherapy for human bone and soft tissue sarcomas

PURPOSE

Tumor-specific replication-selective oncolytic virotherapy is a promising antitumor therapy for induction of cell death in tumor cells but not of normal cells. We previously developed an oncolytic adenovirus, OBP-301, that kills human epithelial malignant cells in a telomerase-dependent manner. Recent evidence suggests that nonepithelial malignant cells, which have low telomerase activity, maintain telomere length through alternative lengthening of telomeres (ALT). However, it remains unclear whether OBP-301 is cytopathic for nonepithelial malignant cells. Here, we evaluated the antitumor effect of OBP-301 on human bone and soft tissue sarcoma cells.

EXPERIMENTAL DESIGN

The cytopathic activity of OBP-301, coxsackie and adenovirus receptor (CAR) expression, and telomerase activity were examined in 10 bone (OST, U2OS, HOS, HuO9, MNNG/HOS, SaOS-2, NOS-2, NOS-10, NDCS-1, and OUMS-27) and in 4 soft tissue (CCS, NMS-2, SYO-1, and NMFH-1) sarcoma cell lines. OBP-301 antitumor effects were assessed using orthotopic tumor xenograft models. The fiber-modified OBP-301 (termed OBP-405) was used to confirm an antitumor effect on OBP-301-resistant sarcomas.

RESULTS

OBP-301 was cytopathic for 12 sarcoma cell lines but not for the non-CAR-expressing OUMS-27 and NMFH-1 cells. Sensitivity to OBP-301 was dependent on CAR expression and not on telomerase activity. ALT-type sarcomas were also sensitive to OBP-301 because of upregulation of human telomerase reverse transcriptase (hTERT) mRNA following virus infection. Intratumoral injection of OBP-301 significantly suppressed the growth of OST and SYO-1 tumors. Furthermore, fiber-modified OBP-405 showed antitumor effects on OBP-301-resistant OUMS-27 and NMFH-1 cells.

CONCLUSIONS

A telomerase-specific oncolytic adenovirus is a promising antitumor reagent for the treatment of bone and soft tissue sarcomas.

Minimally invasive plate osteosynthesis for osteofibrous dysplasia of the tibia: a case report

Osteofibrous dysplasia occurs most frequently in the tibia and may result in deformity and pathological fracture. We report one such case in a 6-year-old girl who underwent minimally invasive plate osteosynthesis using a locking compression plate. The varus deformity of the tibia was manually corrected, and the plate was inserted without extensive surgical exposure. At 20-week follow-up, the fracture had healed completely, and she had returned to normal daily living. At 3-year follow-up, radiographs showed no progression of the varus deformity. Minimally invasive plate osteosynthesis is useful for treatment of pathological fractures caused by osteofibrous dysplasia. It preserves blood flow at the fracture site, leading to good bone healing and stability to prevent further deformity and an early return to daily activity.

Dental pulp cells for induced pluripotent stem cell banking

Defined sets of transcriptional factors can reprogram human somatic cells to induced pluripotent stem (iPS) cells. However, many types of human cells are not easily accessible to minimally invasive procedures. Here we evaluated dental pulp cells (DPCs) as an optimal source of iPS cells, since they are easily obtained from extracted teeth and can be expanded under simple culture conditions. From all 6 DPC lines tested with the conventional 3 or 4 reprogramming factors, iPS cells were effectively established from 5 DPC lines. Furthermore, determination of the HLA types of 107 DPC lines revealed 2 lines homozygous for all 3 HLA loci and showed that if an iPS bank is established from these initial pools, the bank will cover approximately 20% of the Japanese population with a perfect match. Analysis of these data demonstrates the promising potential of DPC collections as a source of iPS cell banks for use in regenerative medicine.

Operative treatment for pincer type femoroacetabular impingement:a case report

Femoroacetabular impingement (FAI) is a condition characterized by the impingement of the femur and acetabulum. In Japan, this disorder has become recognized gradually. Here we report a rare case of surgically treated FAI, associated with an osseous protrusion on the acetabulum of a 30-year-old female. Plain computed tomography (CT) and reconstructive 3D-CT images clearly demonstrated an anterolateral bony protrusion. Hip arthroscopy showed no degeneration of the cartilage on either the femoral or acetabular side, but degeneration at the edge of labrum was observed in the region of the bony protrusion. The complete removal of the bony protrusion under hip arthroscopy was thus considered impracticable, and a small skin incision was therefore made anteriorly to approach the acetabulum. The Short-Form 36-Item Health Survey (SF-36) revealed improvement in all scores.

Surgical treatment of metastatic vertebral tumors

Surgical treatment of metastatic spinal cord compression is controversial. The purpose of this study was to investigate the effectiveness of our current surgical treatments and the use of spinal instrumentation. In this retrospective study covering the years between 1990 and 2006, 100 patients with spinal metastases which were secondary to various cancers underwent posterior and/or anterior decompression with spinal stabilization for the purposes of reduction of pain, and/or to help correct or improve neurological deficits. The group was made up of 60 men and 40 women whose ages ranged from 16 to 83 years (average of 60 years), and the average follow-up period was 14 months. The effect of treatment upon pain relief and neural deficits was assessed, and the cumulative survival rate was calculated by the Kaplan-Meier method. The average surgical time was 185 min. This was calculated based on the following times, listed here with the surgery type: 178 min for posterior surgery; 245 min for anterior surgery;465 min for combined surgery;and 475 min for total en bloc spondylectomy. Average blood loss during surgery was 1,630 ml for posterior surgery, 1,760 ml for anterior surgery, 1,930 ml for combined surgery, and 3,640 ml for total en bloc spondylectomy. Preoperative pain and paralysis were improved by 88% and 53%, respectively. In regards to surgical complications, postoperative epidural hematoma was observed in 2 patients, and instrumentation-related infection was observed in 1. Only 2 patients died within 2 months of surgery. In conclusion, posterior and/or anterior decompression with spinal stabilization is a safe and effective treatment for patients with spinal metastases, and can improve their quality of life.

Characterization of dental pulp stem cells of human tooth germs

In previous studies, human dental pulp stem cells (hDPSCs) were mainly isolated from adults. In this present study, we characterized hDPSCs isolated from an earlier developmental stage to evaluate the potential usage of these cells for tissue-regenerative therapy. hDPSCs isolated at the crown-completed stage showed a higher proliferation rate than those isolated at a later stage. When the cells from either group were cultured in medium promoting differentiation toward cells of the osteo/odontoblastic lineage, both became alkaline-phosphatase-positive, produced calcified matrix, and were also capable of forming dentin-like matrix on scaffolds in vivo. However, during long-term passage, these cells underwent a change in morphology and lost their differentiation ability. The results of a DNA array experiment showed that the expression of several genes, such as WNT16, was markedly changed with an increasing number of passages, which might have caused the loss of their characteristics as hDPSCs.

X-ray dark field imaging of human articular cartilage: possible clinical application to orthopedic surgery

Despite its convenience and non-invasiveness on daily clinical use, standard X-ray radiography cannot show articular cartilage. We developed a novel type of X-ray dark field imaging (DFI), which forms images only by a refracted beam with very low background illumination. We examined a disarticulated distal femur and a shoulder joint with surrounding soft tissue and skin, both excised from a human cadaver at the BL20B2 synchrotron beamline at SPring-8. The field was 90 mm wide and 90 mm high. Articular cartilage of the disarticulated distal femur was obvious on DFI, but not on standard X-ray images. Furthermore, DFI allowed visualization in situ of articular cartilage of the shoulder while covered with soft tissue and skin. The gross appearance of the articular cartilage on the dissected section of the proximal humerus was identical to the cartilage shown on the DFI image. These results suggested that DFI could provide a clinically accurate method of assessing articular cartilage. Hence, DFI would be a useful imaging tool for diagnosing joint disease such as osteoarthritis.

Photodynamic therapy with ATX-S10.Na(II) inhibits synovial sarcoma cell growth

Photodynamic therapy (PDT) is an effective cancer treatment modality that allows selective destruction of malignant tumor cells. We asked whether PDT could inhibit in vivo and in vitro growth of synovial sarcoma cells. We analyzed PDT using ATX-S10.Na(II) and a diode laser for a synovial sarcoma cell line (SYO-1). Photodynamic therapy with ATX-S10.Na(II) showed an in vitro cytotoxic effect on the cultured SYO-1 cells. The in vitro effect of PDT depended on the treatment concentration of ATX-S10.Na(II) and the laser dose of irradiation. ATX-S10.Na(II) was detected in the tumor tissue specimens that were excised from nude mice bearing SYO-1 within 6 hours after intravenous injection, but it was eliminated from the tumor 12 hours after injection. Photodynamic therapy suppressed the tumor growth of nude mice bearing SYO-1, and high-dose irradiation induced no viable tumor cells in histologic specimens. Photodynamic therapy performed after marginal resection of the tumor of nude mice bearing SYO-1 reduced the rate of local recurrence of the tumor. Our results suggest PDT using ATX-S10.Na(II) and laser irradiation may be a potentially useful treatment for synovial sarcoma, especially to reduce the surgical margin and preserve critical anatomic structures adjacent to the tumor.

New approach for assessing vascular distribution within bone tumors using dynamic contrast-enhanced MRI

PURPOSE

To differentiate benign from malignant bone tumors by analyzing the vascular distribution within bone tumors with dynamic contrast-enhanced MRI.

METHODS

We studied dynamic contrast-enhanced MRI for 49 bone tumors (22 malignant and 27 benign tumors). Seven small regions of interest (ROI) were set inside the largest portion of each tumor. Four ROI were placed evenly on the periphery and three ROI were placed evenly on the line of the longest breadth within the tumor. The slope of the curve (%Slope) was calculated on the time-intensity curves of the whole tumor and of each ROI. The variance values for the %Slope of the ROI were calculated to assess the dispersion of the intensity change at each ROI within the tumor.

RESULTS

Mean value of the %Slopes of whole tumor regions for malignant bone tumors (70.4 +/- 60.3%) was significantly higher than that for benign bone tumors (37.6 +/- 52.9%) (P = 0.015), although giant cell tumor (GCT), a locally aggressive tumor, had a relatively higher %Slope. Mean value of the variance of %Slopes for malignant bone tumors (3485.9 +/- 5942.5) was significantly higher than that for all benign tumors (470.4 +/- 583.9) (P = 0.012), indicating that the %Slope values of seven ROI within malignant bone tumors varied more widely compared with the ROI inside benign bone tumors. GCT also demonstrated a lower value.

CONCLUSION

Our method of analyzing the signal intensity change at seven separate regions that evaluates the vascular distribution within a tumor could be a useful tool for differentiating between benign and malignant bone tumors.

Endothelin receptor B2 (EDNRB2) is associated with the panda plumage colour mutation in Japanese quail

The panda mutant in Japanese quail (Coturnix japonica) displays spots of wild-type plumage on a white background and is controlled by an autosomal recessive allele (s). The dotted white is controlled by a third allele (s(dw)) of the s locus with s(dw)/s(dw) quail having less pigmentation than s/s quail. We mapped the s locus to the Japanese quail chromosome 4 (CJA04) in a previous study. The orthologous region of the chicken (Gallus gallus) genome includes endothelin receptor B2 (EDNRB2), an avian-specific paralog of endothelin receptor B (EDNRB). EDNRB mutations in mammals retard the migration of neural crest cells (NCCs), which results in a spotted coat colour and an enteric nervous defect. In the present study, we investigated the association between the s locus and EDNRB2 in Japanese quail. Sequence comparison among transcripts from livers of wild-type, panda and dotted white quail revealed a nucleotide substitution (c.995G>A) leading to a p.R332H amino acid change that was specific to panda, whereas no amino acid substitution was found in dotted white birds. The amino acid position 332 is located in the sixth transmembrane domain and is highly conserved in both avian and mammalian endothelin receptors. The A allele at nucleotide position 995 was specific to panda (s/s) birds among 10 strains, and was mapped to the same chromosomal region as the s locus. Quantitative RT-PCR revealed that EDNRB2 transcripts were reduced in both panda and dotted white mutants compared with wild-type. However, there was no difference between the early embryos of wild-type and panda with respect to the migration of NCCs. The genetic association of EDNRB2 with plumage colour in birds was found for the first time in this study.

Highly frequent allelic loss of chromosome 6q16-23 in osteosarcoma: involvement of cyclin C in osteosarcoma

The molecular pathogenesis of osteosarcoma is very complicated and associated with chaotic abnormalities on many chromosomal arms. We analyzed 12 cases of osteosarcomas with comparative genomic hybridization (CGH) to identify chromosomal imbalances, and detected highly frequent chromosomal alterations in chromosome 6q, 8p, 10p and 10q. To define the narrow rearranged region on chromosome 6 with higher resolution, loss of heterozygosity (LOH) analysis was performed with 21 microsatellite markers. Out of 31 cases, 23 cases (74%) showed allelic loss at least with one marker on chromosome 6q. We identified two distinct commonly deleted regions on chromosome 6 using markers D6S1565 located at 6q16 and 6q23MS1 at 6q23. The expression analysis of genes located at the deleted region was performed, and the decreased mRNA expression of the CCNC gene, one of the regulators of cell cycle, was detected. Growth of osteosarcoma cell line was significantly suppressed after the CCNC cDNA transfection. Fine mapping of the deleted region containing a possible tumor suppressor gene and the transfection assay suggest that the CCNC is a candidate tumor suppressor gene.