Hiroyuki Futani

Interleukin-18 and Interleukin-12 Synergistically Inhibit Osteoclastic Bone-resorbing Activity

The effect of interleukin (IL)-18 on osteoclastic bone-resorbing activity was investigated in vitro. Osteoclast-enriched cells, about 70% of which were tartrate-resistant acid phosphatase (TRAP)-positive, were cultured on dentine slices, and then the total volume of resorption pits on each dentine slice was measured as bone-resorbing activity. When the effects of IL-18 alone at 1, 10, 100, and 1000 ng/mL were examined, bone-resorbing activity was significantly reduced only at 1000 ng/mL, by about 50%. However, IL-18 plus IL-12 (10 ng/mL each) reduced bone-resorbing activity by about 70%, whereas IL-12 alone had no significant effect. When the concentration of interferon (IFN)-gamma in the medium was measured, IL-18 or IL-12 was found to increase it slightly, and the combination of these two cytokines synergistically increased it. The inhibitory effect of the combination of the two cytokines was completely abolished by the addition of an anti-IFN-gamma neutralizing antibody to the medium, but IFN-gamma by itself did not inhibit osteoclastic bone resorption. IL-18 alone or in combination with IL-12 did not affect the number of TRAP-positive cells in culture of osteoclast-enriched cells. Osteoclasts prepared from osteoclast-enriched cells expressed mRNAs of IL-18 receptor, MyD88, and cathepsin K. Furthermore, IL-18 receptor protein was detected on the cell surface of osteoclasts. The present results indicate that the combination of IL-18 and IL-12 synergistically inhibits osteoclastic bone-resorbing activity, suggesting that IFN-gamma participates in the mechanism underlying this inhibition.

Long-term follow-up after limb salvage in skeletally immature children with a primary malignant tumor of the distal end of the femur.

BACKGROUND Skeletally immature children with a primary malignant tumor in the distal end of the femur are candidates for limb-salvage surgery; however, functional impairment due to subsequent limb-length discrepancy must be considered. Our aim was to evaluate the long-term clinical outcome of limb salvage in patients with a sarcoma of the distal end of the femur who were eleven years old or less, focusing on limb-length discrepancy and complications. METHODS The cases of forty children were retrospectively reviewed in a multicenter study based on the responses to a questionnaire. Twenty-eight patients had had endoprosthetic reconstruction, and twelve had had biological reconstruction. Functional evaluation was based on the Musculoskeletal Tumor Society scoring system, with numerical values from 0 to 5 points assigned for each of the following six categories: pain, function, emotional acceptance, use of supports, walking ability, and gait. These values were added, and the functional score was presented as a percentage of the maximum possible score. Limb-length discrepancy was measured with orthoroentgenograms. Complications and their treatment were analyzed. Patient survival and the survival of the reconstructions were analyzed with use of the Kaplan-Meier method. RESULTS Seven patients died and thirty-three remained alive, for a survival rate of 82% at ten years postoperatively. For the surviving patients, the mean follow-up periods (and standard deviations) were similar for the twenty-two who had endoprosthetic reconstruction (13.2 +/- 3.9 years) and the eleven who had biological reconstruction (10.4 +/- 4.4 years). All patients had reached skeletal maturity. The mean final functional score was 74% +/- 18% in the endoprosthetic reconstruction group and 68% +/- 17% in the biological reconstruction group (p = 0.37). For the nineteen patients who underwent limb-lengthening, the mean functional score increased significantly from 65% +/- 21% before the procedure to 81% +/- 11% after the lengthening (p = 0.0016). There were five early and twenty-eight late complications. In the endoprosthetic reconstruction group, the most frequent complications were deep infection and aseptic loosening. In the biological reconstruction group, the most frequent complications were implant breakage and nonunion. Revision surgeries were required in seventeen patients, including five who had an amputation. The rate of survival of the endoprosthetic reconstructions was 77% at five years and 51% at ten years postoperatively, whereas the rate of survival of the biological reconstructions was 46% at both five and ten years postoperatively. CONCLUSIONS Endoprosthetic or biological reconstructions as limb salvage provided good functional outcome in skeletally immature children with a malignant bone tumor of the distal aspect of the femur despite a high rate of revisions and limb-lengthening procedures.

Relation between interleukin-18 and PGE2 in synovial fluid of osteoarthritis: a potential therapeutic target of cartilage degradation.

Osteoarthritis (OA) is characterized by articular cartilage degradation and hypertrophic joint changes. Interleukin (IL)-18 is a potent inducer of prostaglandin (PG) E2 in vitro. We determined the relation between IL-18 and PGE2 in synovial fluid (SF) of human OA, and discussed the role of IL-18 in the pathogenesis of OA and also its therapeutic consequences. SF was collected from 30 patients with knee OA. The concentrations of IL-18 and other cytokines including IL-1&bgr;, tumor necrosis factor (TNF)-&agr;, IL-6, and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). The concentration of PGE2 was also assessed by inhibitory ELISA. The average value of IL-18 was 248 ± 310 pg/mL. The average value of PGE2 was 93 ± 103 pg/mL. There was a relatively strong correlation between IL-18 and PGE2 (r = 0.78, p = 0.0001). In contrast, IL-1&bgr; was undetectable (cutoff point of 20 pg/mL), except for one case. TNF-&agr; was also undetectable (cutoff point of 20 pg/mL), except for two cases. The average value of IL-6 was 1,310 ± 2,623 pg/mL (n = 17), whereas IL-8 was 5,208 ± 6,031 pg/mL (n = 5). Furthermore, IL-6 and IL-8 correlated with IL-18 (r = 0.69, p = 0.0024 and r = 0.87, p = 0.0527, respectively). Our results suggest that IL-18 could play a major role in vivo in inducing the production of PGE2, which in turn can cause cartilage degradation in OA pathogenesis. Thus, targeting this cytokine appears to be an important therapeutic approach in OA.

Enhanced suppression of pulmonary metastasis of malignant melanoma cells by combined administration of α-galactosylceramide and interleukin-18

α‐Galactosylceramide (α‐GalCer) shows antitumor effects by activating natural killer (NK) cells indirectly through stimulation of the secretion of cytokines by NKT cells, whereas interleukin (IL)‐18 shows antitumor effects by activating NK cells directly. In the present study, we examined the antitumor effect of the combined administration of α‐GalCer and IL‐18. An injection of NK cell‐sensitive mouse B16 melanoma cells into a mouse tail vein produced pulmonary metastasis. The daily administration of α‐GalCer or IL‐18 alone for 4 days starting 1 day after the injection of B16 melanoma cells markedly suppressed the number of pulmonary metastatic foci, and their combined administration enhanced the antitumor effect compared with single administration. The antitumor effect of their combined administration was completely abolished by treatment of mice with anti‐asialo GM1 serum, which depletes NK cells but not NKT cells. Combined administration of α‐GalCer and IL‐18 enhanced the cytotoxicity of NK cells and increased the number of NK cells in the lung. Analysis of NKT cell‐dependent and NK cell‐independent secretion of cytokines, to which NK cells can respond, showed that the administration of α‐GalCer increased the secretion of IL‐2, IL‐4, interferon‐γ, IL‐12, granulocyte‐macrophage colony‐stimulating factor, tumor necrosis factor‐α, and IL‐10, and the combined administration of α‐GalCer and IL‐18 enhanced the secretion of IL‐2, IL‐4, interferon‐γ, and granulocyte‐macrophage colony‐stimulating factor further but only slightly. These results show that IL‐18 in combination with α‐GalCer exerts an antitumor effect on NK cell‐sensitive tumors primarily by the direct stimulation of NK cells by IL‐18 and the indirect stimulation of NK cells by α‐GalCer through its activation of NKT cells. (Cancer Sci 2008; 99: 113–120)

Valproic acid cooperates with hydralazine to augment the susceptibility of human osteosarcoma cells to Fas- and NK cell-mediated cell death

We investigated the effects of valproic acid (VPA), a histone deacetylase inhibitor, in combination with hydralazine, a DNA methylation inhibitor, on the expression of cell-surface Fas and MHC-class I-related chain molecules A and B (MICA and B), the ligands of NKG2D which is an activating receptor of NK cells, and on production of their soluble forms in HOS, U-2 OS and SaOS-2 human osteosarcoma cell lines. We also examined the susceptibility of these cells to Fas- and NK cell-mediated cell death. VPA did not increase the expression of Fas on the surface of osteosarcoma cells, while hydralazine did, and the combination of VPA with hydralazine increased the expression of cell-surface Fas. In contrast, the combination of VPA with hydralazine did not increase the production of soluble Fas by osteosarcoma cells. Both VPA and hydralazine increased the expression of cell-surface MICA and B in osteosarcoma cells, and their combination induced a greater increase in their expression. VPA inhibited the production of both soluble MICA and MICB by osteosarcoma cells while hydralazine produced no effect. Both VPA and hydralazine enhanced the susceptibility of osteosarcoma cells to Fas- and NK cell-mediated cell death and the combination of VPA with hydralazine further enhanced the effects. The present results suggest that combined administration of VPA and hydrazine is valuable for enhancing the therapeutic effects of immunotherapy for osteosarcomas.

Inhibition by Interleukin-18 of the Growth of Dunn Osteosarcoma Cells

To examine the usefulness of interleukin-18 (IL-18) in the treatment of osteosarcomas, the effect of IL-18 on the growth of Dunn osteosarcoma cells was investigated. Daily intraperitoneal (i.p.) injection of mouse recombinant IL-18 (2 microg/mouse) suppressed the growth of Dunn osteosarcoma cells transplanted subcutaneously (s.c.) into syngeneic C3H mice. This IL-18-induced suppression was not affected by simultaneous treatment with anti-asialo GM1 serum, which inactivates natural killer (NK) cells. However, IL-18 failed to suppress the growth of Dunn osteosarcoma cells transplanted into BALB/c-nude mice devoid of T lymphocytes or C3H-gld/gld mice deficient in functional Fas ligand (FasL). IL-18 also failed to suppress the growth of Dunn osteosarcoma cells in vitro, although expression of IL-18 receptor mRNA and MyD88 mRNA as well as Fas mRNA was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). On the other hand, antimouse Fas antibody showed cytotoxicity against Dunn osteosarcoma cells in a dose-dependent manner in vitro. In addition, treatment of C3H mice with IL-18 enhanced the cytotoxic activity of CD8(+) T lymphocytes against Dunn osteosarcoma cells. These results indicate that IL-18 inhibits the growth of Dunn osteosarcoma cells in vivo by enhancing the cytotoxic activity of CD8(+) T lymphocytes through the FasL-Fas system.

Sodium valproate, a histone deacetylase inhibitor, decreases the secretion of soluble Fas by human osteosarcoma cells and increases their sensitivity to Fas-mediated cell death

PurposeEffects of valproic acid (VPA), a histone deacetylase inhibitor, on the susceptibility to cell death induced by agonistic anti-Fas antibody were examined using four human osteosarcoma cell lines.MethodCell growth, secretion of soluble Fas, expression of cell-surface Fas, and sensitivity to Fas-mediated cell death were examined using cell proliferation assay, flow cytometry, enzyme-linked immunosorbent assay, and agonistic anti-Fas antibody, respectively.ResultsVPA suppressed the growth of all the four osteosarcoma cell lines and the secretion of soluble Fas from these cells. VPA showed no or slight suppressive effect on the expression of cell-surface Fas in the four osteosarcoma cell lines, but increased the sensitivity of three of four osteosarcoma cell lines to Fas-mediated cell death.ConclusionVPA enhances the susceptibility of human osteosarcoma cells to Fas-ligand-induced cell death by decreasing the secretion of soluble Fas and increasing the sensitivity to Fas-mediated cell death.

A rare case of clear cell sarcoma with 4 types of EWSR1-ATF1 fusions detected not in primary site but in metastatic site.

Clear cell sarcoma is a unique tumor which has EWSR1-ATF1 or EWSR1-CREB1 fusion. Several patterns of EWSR1-ATF1 fusion are observed in clear cell sarcoma. Since type 5-7 fusions were reported recently, they are classified as type 1-7. We examined EWSR1-ATF1 and EWSR1-CREB1 fusions in a single case of clear cell sarcoma with lung metastasis in a 36-year-old Japanese man. As a result, we found only type 1 EWSR1-ATF1 fusion in the primary site, but 4 types of EWS-ATF1 fusion (type 1, 2, 5, 6) were detected in the metastatic site. These 4 types of fusion were completely identical to the recent report, but the case had the same fusion patterns in both primary and metastatic sites. In our case, increased splicing activity in the EWSR1-ATF1 fusion might be acquired at the metastatic site. There is another possibility that metastasis might develop through the increased splicing activity in the fusion.

Microgeodic disease affecting the toes in athletes: a report of 2 cases.

Microgeodic disease is a rare clinical condition first described by Maroteaux in 1970. Clinical manifestation of this disease is characterized by spindle-shaped swelling, redness, local heat, tenderness, and pain in the affected phalanx, usually of the fingers, in children. Radiographic examination of the affected phalanx exhibits characteristic and diagnostic findings consisting of small lacunae and cortical irregularity. The disease usually occurs during the wintertime and resolves spontaneously as the climate gets warm. Therefore, it is generally thought that the disease process is self-limiting.2-6 In this report, we present 2 cases of microgeodic disease occurring in association with sports activities. In both cases, initial diagnosis was delayed, resulting in prolonged morbidity and stress fractures. The reported cases illustrate the importance of raising awareness of this disease as a potential sports-related problem in children.

Immunotherapy with Interleukin-18 in Combination with Preoperative Chemotherapy with Ifosfamide Effectively Inhibits Postoperative Progression of Pulmonary Metastases in a Mouse Osteosarcoma Model

The effect of immunotherapy with interleukin-18 (IL-18) in combination with preoperative chemotherapy on the postoperative progression of pulmonary metastasis was examined using a spontaneous pulmonary metastasis model of mouse osteosarcoma. Mice were inoculated subcutaneously with highly metastatic murine osteosarcoma cells (LM8) and then underwent chemotherapy with ifosfamide (30 or 60 mg/kg body weight, days 14–16), immunotherapy with IL-18 (2 μg/mouse, days 18–24) or combined immunotherapy and chemotherapy. Tumors developed in mice were excised 21 days after cell inoculation when microscopic but not macroscopic pulmonary metastasis was observed in mice. Three weeks after the excision of the tumors, macroscopic pulmonary metastasis was observed on the surface of the lung. Administration of ifosfamide or IL-18 alone decreased the number of macroscopic pulmonary metastases, and combined administration of ifosfamide and IL-18 resulted in much greater inhibition of pulmonary metastasis. These results suggest that immunotherapy in combination with preoperative chemotherapy is highly effective in suppressing postoperative progression of pulmonary metastasis.