Ken Kageyama

Differentiating benign notochordal cell tumors from chordomas: radiographic features on MRI, CT, and tomography.

OBJECTIVE The purpose of this study was to characterize the imaging spectrum of benign notochordal cell tumors (BNCTs) and chondromas and to determine if this helped in differentiating BNCTs from chordomas. MATERIALS AND METHODS Thirty-eight patients pathologically diagnosed with chordomas were reviewed and ultimately diagnosed to have five BNCTs and 33 chordomas. The following radiologic findings were reevaluated by two radiologists by consensus: extraosseous extension, osseous change on CT or conventional tomography, T2-weighted MR signal intensity, T2-weighted signal homogeneity, and contrast-enhanced T1-weighted MR signal intensity. Fishers exact test was performed to determine statistical significance. RESULTS Our study yielded five results. First, four of five BNCTs (80%) were intraosseous, whereas 31 of 33 chordomas (94%) were both intra- and extraosseous (p < 0.0001). Second, all BNCTs showed mild osteosclerosis without bone destruction; all chordomas showed variable osteolysis (p = 0.0092). Third, all BNCTs and 28 of 33 chordomas (85%) showed hyperintensity on T2-weighted images (p > 0.05). Fourth, four of five BNCTs (80%) and 27 of 33 chordomas (82%) were heterogeneous on T2-weighted images (p > 0.05). Fifth, no BNCTs enhanced, whereas all chordomas variably enhanced (p < 0.0001). CONCLUSION Radiologic studies may allow distinction of BNCTs from chordomas.

Radiofrequency Ablation and Immunostimulant OK-432: Combination Therapy Enhances Systemic Antitumor Immunity for Treatment of VX2 Lung Tumors in Rabbits

PURPOSE To evaluate whether antitumor immunity is enhanced systemically by combining radiofrequency ablation (RFA) and local injection of an immunostimulant, OK-432. MATERIALS AND METHODS Experiments were approved by the institutional animal care committee. Experimental Japanese rabbits inoculated with VX2 tumors in the lung and the auricle were randomized into four groups of eight: control (supportive care), RFA (RFA of lung tumor), OK-432 (direct injection of OK-432 into lung tumor), and combination therapy (lung RFA and direct OK-432 injection into lung tumor). All procedures were performed 1 week after implantation of VX2 tumors (week 1). In addition, a VX2 tumor rechallenge test was performed in the RFA and combination therapy groups. Survival time was evaluated by means of the Kaplan-Meier method and by using the log-rank test for intergroup comparison. Mean auricle tumor volumes were calculated every week. Specific growth rates (SGRs) were calculated and compared by using the Mann-Whitney test. RESULTS The median survival times of the control, RFA, OK-432, and combination therapy groups were 23, 36.5, 46.5, and 105 days, respectively. Survival was significantly prolonged in the combination therapy group when compared with the other three groups (P <.05). The mean auricle tumor volume decreased only in the combination therapy group. The mean auricle tumor volumes of the combination therapy group from week 1 to week 7 were 205, 339, 264, 227, 143, 127, and 115 mm(3). SGR in the combination therapy group became significantly smaller than those in the other three groups (P < .05). In the rechallenge test, the volume of all reimplanted tumors decreased. CONCLUSION Combining RFA with local injection of immunostimulant OK-432 may lead to indirectly activation of systemic antitumor immunity.

Paracrine effect of NRG1 and HGF drives resistance to MEK inhibitors in metastatic uveal melanoma

Uveal melanoma patients with metastatic disease usually die within one year, emphasizing an urgent need to develop new treatment strategies for this cancer. MEK inhibitors improve survival in cutaneous melanoma patients but show only modest efficacy in metastatic uveal melanoma patients. In this study, we screened for growth factors that elicited resistance in newly characterized metastatic uveal melanoma cell lines to clinical-grade MEK inhibitors, trametinib and selumetinib. We show that neuregulin 1 (NRG1) and hepatocyte growth factor (HGF) provide resistance to MEK inhibition. Mechanistically, trametinib enhances the responsiveness to NRG1 and sustained HGF-mediated activation of AKT. Individually targeting ERBB3 and cMET, the receptors for NRG1 and HGF, respectively, overcome resistance to trametinib provided by these growth factors and by conditioned medium from fibroblasts that produce NRG1 and HGF. Inhibition of AKT also effectively reverses the protective effect of NRG1 and HGF in trametinib-treated cells. Uveal melanoma xenografts growing in the liver in vivo and a subset of liver metastases of uveal melanoma patients express activated forms of ERBB2 (the coreceptor for ERBB3) and cMET. Together, these results provide preclinical evidence for the use of MEK inhibitors in combination with clinical-grade anti-ERBB3 or anti-cMET monoclonal antibodies in metastatic uveal melanoma.

Arterial Blood, Rather Than Venous Blood, is a Better Source for Circulating Melanoma Cells

Background CTCs provide prognostic information and their application is under investigation in multiple tumor types. Of the multiple variables inherent in any such process, none is more important to outcome than the appropriateness of the sample source. To address this question, we investigated CTCs in paired peripheral venous and arterial blood specimens obtained from stage IV uveal melanoma patients. Methods Blood specimens were obtained from both common femoral arteries and antecubital veins in 17 uveal melanoma patients with multiple hepatic metastases for CTC measurements. Finding CTCs were detectable with greater frequency (100%) and in larger numbers (median 5, range 1 to 168) in all arterial blood specimens than in venous samples (52.9%; median 1, range 0 to 8). Patients with hepatic as well as extra-hepatic metastasis showed higher number of arterial CTCs, compared to patients with liver-only metastasis (p = 0.003). There was no significant association between the number of arterial CTCs and the tumor burden within the liver in patients who had liver-only metastases. Interpretation Our data indicate that arterial blood specimens might be a better source of circulating uveal melanoma cells. Although less conveniently processed, perhaps arterial blood should be evaluated as sample source for measurement of CTCs.

Co-targeting HGF-cMET signaling with MEK inhibitors in metastatic uveal melanoma

Patients with metastatic uveal melanoma usually die within 1 year of diagnosis, emphasizing an urgent need to develop new treatment strategies. The liver is the most common site of metastasis. Mitogen-activated protein kinase kinase (MEK) inhibitors improve survival in V600 BRAF–mutated cutaneous melanoma patients but have limited efficacy in patients with uveal melanoma. Our previous work showed that hepatocyte growth factor (HGF) signaling elicits resistance to MEK inhibitors in metastatic uveal melanoma. In this study, we demonstrate that expression of two BH3-only family proteins, Bim-EL and Bmf, contributes to HGF-mediated resistance to MEK inhibitors. Targeting HGF/cMET signaling with LY2875358, a neutralizing and internalizing anti-cMET bivalent antibody, and LY2801653, a dual cMET/RON inhibitor, overcomes resistance to trametinib provided by exogenous HGF and by conditioned medium from primary hepatic stellate cells. We further determined that activation of PI3Kα/γ/δ isoforms mediates the resistance to MEK inhibitors by HGF. Combination of LY2801653 with trametinib decreases AKT phosphorylation and promotes proapoptotic PARP cleavage in metastatic uveal melanoma explants. Together, our data support the notion that selectively blocking cMET signaling or PI3K isoforms in metastatic uveal melanoma may break the intrinsic resistance to MEK inhibitors provided by factors from stromal cells in the liver. Mol Cancer Ther; 16(3); 516–28. ©2017 AACR.

Combination Radiofrequency Ablation and Local Injection of the Immunostimulant Bacillus Calmette–Guérin Induces Antitumor Immunity in the Lung and at a Distant VX2 Tumor in a Rabbit Model

PURPOSE To evaluate whether the combination of radiofrequency (RF) ablation and local injection of the immunostimulant Mycobacterium bovis bacillus Calmette-Guérin (BCG) induces systemic antitumor immunity. MATERIALS AND METHODS Japanese White rabbits with lung and auricle VX2 tumors were randomized into three groups: control (n = 8; no treatment), RF ablation only (n = 8; RF ablation to the lung tumor), and RF ablation with local BCG injection into the lung tumor (n = 8). Treatments were performed 1 week after tumor implantation. Survival was evaluated with Kaplan-Meier method and log-rank test. Weekly mean volume and specific growth rate (SGR) of auricle tumors were calculated, and comparisons were made by Mann-Whitney test. RESULTS Median survival of control, RF-only, and RF/BCG groups were 23, 41.5, and 103.5 days, respectively. Survival was significantly prolonged in the RF-only and RF/BCG groups compared with the control group (P = .034 and P =.003, respectively), but no significant difference was found between the RF-only and RF/BCG groups (P = .279). Only in the RF/BCG group was mean auricle tumor volume decreased 5 weeks after implantation. No significant difference in SGR was found between the control and RF-only groups (P = .959), but SGR in the RF/BCG group was significantly lower than in the control group (P = .005). CONCLUSIONS The combination of RF ablation and local injection of BCG resulted in distant tumor suppression compared with the control group, whereas RF ablation alone did not produce this effect. Therefore, the combination of RF ablation and local injection of BCG may induce systemic antitumor immunity.

Injectable cell scaffold restores impaired cell-based therapeutic angiogenesis in diabetic mice with hindlimb ischemia

The clinical success of cell-based therapeutic angiogenesis has been limited in diabetic patients with critical limb ischemia. We previously reported that an injectable cell scaffold (ICS), which is a nano-scaled hydroxyapatite (HAp)-coated polymer microsphere, enhances therapeutic angiogenesis. Subsequently, we developed a modified ICS for clinical use, measuring 50 μm in diameter using poly(l-lactide-co-ε-caprolactone) as a biodegradable polymer, which achieved appropriately accelerated absorption in vivo. The aim of the present study was to evaluate the effectiveness of this practical ICS in diabetic hindlimb ischemia. Bone-marrow mononuclear cells (BMNCs) were intramuscularly injected, without or with a practical ICS, into the ischemic hindlimbs of mice (BMNCs or ICS+BMNCs group, respectively). Kaplan-Meier analysis demonstrated that the beneficial effects of BMNC transplantation for limb salvage after ischemic surgery were almost entirely abrogated in streptozotocin-induced diabetic mice. In contrast, injection of ICS+BMNCs revealed significant limb salvage in diabetic mice to a similar extent as in non-diabetic mice. The number of apoptotic transplanted BMNCs was 1.8-fold higher in diabetic mice 10 days after transplantation compared to non-diabetic mice, while that in the ICS+BMNCs group was markedly lower (8.3% of that in the BMNCs group) even in diabetic mice. The proangiogenic factors VEGF and FGF2, also known as antiapoptotic factors, mostly co-localized with transplanted GFP-positive BMNCs that were closely aggregated around the ICS in ischemic tissue. In conclusion, the practical ICS significantly augmented cell-based therapeutic angiogenesis even in diabetic animals, through local accumulation of proangiogenic factors and antiapoptotic effects in transplanted cells.

Prediction for Improvement of Liver Function after Balloon-Occluded Retrograde Transvenous Obliteration for Gastric Varices to Manage Portosystemic Shunt Syndrome.

PURPOSE To investigate predictive factors and cutoff value of transient elastography (TE) measurements for assessing improvement in liver function after balloon-occluded retrograde transvenous obliteration (BRTO) for gastric varices (GV). MATERIALS AND METHODS Retrospective analysis was performed of 50 consecutive patients followed for > 3 months after BRTO, who had undergone TE before BRTO between January 2011 and February 2015. The correlation between change in liver function (total bilirubin, albumin, and prothrombin time) and baseline liver function values and liver stiffness measurement (LSM) by TE was evaluated by Pearson correlation test. Receiver operating characteristic curves were used to determine cutoff values for discriminating between patients who had improved liver function and patients who did not. The time interval from BRTO to aggravation of esophageal varices (EV) (worsening morphology, development of new varices, or variceal rupture) grouped by cutoff values was also analyzed. RESULTS Serum albumin was significantly improved at 3 months after BRTO (3.57 g/dL vs 3.74 g/dL, P < .001). There was a significant negative correlation between change in albumin and baseline LSM (r = -0.50, P < .001). The best cutoff point for LSM was ≤ 22.9 kPa, with sensitivity and specificity of 78.4% and 69.2%, respectively, for predicting which patients would have improved albumin after BRTO. Among 33 patients, 29 (88%) patients had improved albumin. The 1-year progression rate of EV after BRTO was 13.6% in patients with LSM ≤ 22.9 kPa. CONCLUSIONS The predictive factor for improvement in albumin after BRTO was lower LSM (≤ 22.9 kPa) using TE.

Chest wall temperature during radiofrequency ablation in a normal rabbit lung model

PurposeThe aim of this study was to examine the actual temperature during lung radiofrequency ablation (RFA) and pathological changes due to thermal damage in the pleural tissue of the chest wall in a rabbit model.Material and methodsThe study was conducted on 14 Japanese white rabbits with normal lungs. Under computed tomography guidance, the electrode with a 2-cm expandable tip was inserted into the lower lung lobe and positioned so the tip of the needle touched the thoracic wall upon expansion. A thermometer was inserted 5 mm lateral to the point of electrode insertion. RFA was applied at 30 W (n = 7) or 15 W (n = 7) until maximum impedance (i.e., roll-off) or for 4 min at the longest. Local tissue temperature was recorded. The chest wall was dissected out immediately after RFA for histological examination.ResultsThe mean (± SD) maximum tissue temperature at 30 W (86.7° ± 10.0°C) was not significantly different from that at 15 W (82.1° ± 6.2°C). The mean ablation time to increase tissue temperature to 50°, 60°, and 70°C was faster at 30 W (13, 27, and 49 s, respectively) than at 15 W (13, 56, and 115 s, respectively) (P < 0.05). Histological examination showed pleural sloughing at the point of needle insertion and ring-shaped thermal injury in the chest wall.ConclusionWith rabbit lung RFA near the chest wall, ablation immediately below the pleura resulted in a rise of local tissue temperature to >80°C and thermal injury.

Abstract 623: Feasibility of surgical orthotopic implantation for establishment of patient-derived liver metastatic uveal melanoma xenograft model in NSG mouse

The prognosis of metastatic uveal melanoma (UM) is extremely poor. Approximately 90% of patients with metastatic UM die from hepatic metastasis. Controlling hepatic metastases has been a rational approach to extend survival. This raises an urgent need to develop a novel mouse model for further investigation. Patient-derived tumor xenograft (PDX) mouse model provides potential benefit through a personalized medicine approach. This model may be useful for predictions of clinical outcomes, drug efficacy and biomarker identification. Most PDX models, including UM PDX models, are made by ectopic subcutaneous implantation. Subcutaneous PDX models have some obstacles in translational research due to differences in anatomic microenvironment from tumor origin, low engraftment rate, and slow tumor growth. Our goal was to develop an orthotopic PDX model of liver metastatic UM which would overcome these difficulties. In developing our model, we first compared the differences in growth in a liver with a subcutaneous site using two UM cell lines (UM001 and UM004) in NSG mice, to ascertain which site is a more suitable tumor microenvironment. Second, we investigated the feasibility of surgical orthotopic implantation (SOI) of tumor masses to develop a practical liver tumor xenograft mouse model with UM cell lines in 20 mice. Finally, we tried to establish an orthotopic PDX mouse model of liver metastatic UM in 5 mice. We also evaluated concordance for tumor characteristics between pre-implant and post-implant tumors. Our results showed that the liver was a more suitable microenvironment to grow the two UM cell lines compared to the subcutaneous site. UM001 engrafted in the liver, whereas it did not engraft in the subcutaneous site. UM004 displayed more rapid growth in the liver compared to the subcutaneous site. A new SOI of tumor chunk was created to develop a practical liver tumor xenograft model. Donor tumors, which were generated in the liver after injecting UM cell lines, were surgically transplanted into the liver of recipient mice. The new SOI was successfully performed in all 20 mice without adverse events. Recipient mice formed tumors in the liver after SOI. For comparison, the tumor chunks of UM cell lines were also implanted subcutaneously, in which we were able to show that the growth was more rapid in the liver. Both donor and recipient tumors had matching tumor characteristics in histological and proteomic analysis. We established an orthotopic PDX mouse model of liver metastatic UM with a new SOI method. The success rate of engraftment was 80% (4/5) within 6 months. Tumor characteristics of both patient9s original tumors and xenograft mouse tumors matched in histological, genomic and proteomic analysis. This new SOI method can establish a patient-derived liver metastatic uveal melanoma xenograft model in NSG mouse at a highly successful rate. Citation Format: Ken Kageyama, Masahiro Ohara, Kengo Saito, Shinji Ozaki, Mizue Terai, Andrew E. Aplin, Michael J. Mastrangelo, Takami Sato. Feasibility of surgical orthotopic implantation for establishment of patient-derived liver metastatic uveal melanoma xenograft model in NSG mouse. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 623.