PET imaging of 11C-labeled thiamine tetrahydrofurfuryl disulfide, vitamin B1 derivative: First-in-human study.

Vitamine B1 thiamine is an essential component for glucose metabolism and energy production. The disulfide derivative, thiamine tetrahydrofurfuryl disulfide (TTFD), is more absorbent compared to readily-available water-soluble thiamine salts since it does not require the rate-limiting transport system required for thiamine absorption. However, the detailed pharmacokinetics of thiamine and TTFD under normal and pathological conditions were not clarified yet. Recently, 11C-labeled thiamine and TTFD were synthesized by our group, and their pharmacokinetics were investigated by PET imaging in normal rats. In this study, to clarify the whole body pharmacokinetics of [11C]TTFD in human healthy volunteers, we performed first-in-human PET imaging study with [11C]TTFD, along with radiation dosimetry of [11C]TTFD in humans. METHODS: Synthesis of [11C]TTFD was improved for clinical study. Dynamic whole-body PET images were acquired on three young male normal subjects after intravenous injection of [11C]TTFD. VOIs were defined for source organs on the PET images to measure time-course of [11C]TTFD uptake as percentage injected dose and the number of disintegrations for each organ. Radiation dosimetry was calculated with OLINDA/EXM. RESULTS: We succeeded in developing the improved synthetic method of [11C]TTFD for the first-in-human PET study. In the whole body imaging, uptake of [11C]TTFD by various tissues was almost plateaued at 10 min after intravenous injection, afterward gradually increased for the brain and urinary bladder (urine). %Injected dose was high in the liver, kidney, urinary bladder, heart, spine, brain, spleen, pancreas, stomach, and salivary glands, in this order. %Injected dose per gram of tissue was high also in the pituitary. By dosimetry, the effective radiation dose of [11C]TTFD calculated was 5.5 µSv/MBq (range 5.2-5.7). CONCLUSION: Novel synthetic method enabled clinical PET study with [11C]TTFD, which is a safe PET tracer with a dosimetry profile comparable to other common 11C-PET tracers. Pharmacokinetics of TTFD in the pharmacological dose and at different nutritional states could be further investigated by future quantitative PET studies. Noninvasive in vivo PET imaging for pathophysiology of thiamine-related function may provide diagnostic evidence of novel information about vitamin B1 deficiency in human tissues.

Prevalence and associated factors of orphan symptoms in advanced cancer patients: a multicenter observational study.

PURPOSE: The aims of this study were to examine the prevalence of myoclonus, sweating, pruritus, hiccup, and vesical and rectal tenesmus, and to explore associated factors in patients with advanced cancer. METHODS: This multicenter prospective cohort study was conducted in 23 inpatient hospices/palliative care units in Japan from January to December 2017. The prevalence and characteristics of each symptom were assessed on admission and in the 3 days before death. We selected factors that might influence the occurrence of each symptom and investigated the association. RESULTS: A total of 1896 patients were enrolled. The prevalence of orphan symptoms rose from admission to the 3 days before death: myoclonus 1.3 to 5.3% (95% CI 0.9-1.9%/4.3-6.5%), sweating 1.8 to 4.1% (95% CI 1.3-2.6%/3.1-5.1%), hiccup 1.1 to 1.8% (95% CI 0.7-1.7%/1.2-2.6%), and tenesmus 0.7 to 0.9% (0.4-1.2%/0.5-1.5%). Prevalence of pruritus fell from 3.5 to 2.5% (95% CI 2.7-4.4%/1.8-3.4%). Sweating, pruritus, and hiccups persisted throughout the day in nearly half of the patients. Myoclonus was significantly associated with brain tumors, sweating with opioids and antipsychotics, pruritus with liver and biliary tract cancer, cholestasis and severe diabetes, hiccup with male gender, digestive tract obstruction, severe diabetes, and renal failure. Vesical tenesmus was associated with urinary cancer, antipsychotics, and anticholinergics and rectal tenesmus with pelvic cavity cancer. CONCLUSION: We found that orphan symptoms occurred in 0.5-5.0% of patients, increased over time except for pruritus, and persisted in half of the patients.

Combined visual and semi-quantitative assessment of 123I-FP-CIT SPECT for the diagnosis of dopaminergic neurodegenerative diseases.

Visual and semi-quantitative assessments of 123I-FP-CIT single-photon emission computed tomography (SPECT) are useful for the diagnosis of dopaminergic neurodegenerative diseases (dNDD), including Parkinson's disease, dementia with Lewy bodies, progressive supranuclear palsy, multiple system atrophy, and corticobasal degeneration. However, the diagnostic value of combined visual and semi-quantitative assessment in dNDD remains unclear. Among 239 consecutive patients with a newly diagnosed possible parkinsonian syndrome who underwent 123I-FP-CIT SPECT in our medical center, 114 patients with a disease duration less than 7 years were diagnosed as dNDD with the established criteria or as non-dNDD according to clinical judgment. We retrospectively examined their clinical characteristics and visual and semi-quantitative assessments of 123I-FP-CIT SPECT. The striatal binding ratio (SBR) was used as a semi-quantitative measure of 123I-FP-CIT SPECT. We calculated the sensitivity and specificity of visual assessment alone, semi-quantitative assessment alone, and combined visual and semi-quantitative assessment for the diagnosis of dNDD. SBR was correlated with visual assessment. Some dNDD patients with a normal visual assessment had an abnormal SBR, and vice versa. There was no statistically significant difference between sensitivity of the diagnosis with visual assessment alone and semi-quantitative assessment alone (91.2 vs. 86.8%, respectively, p = 0.29). Combined visual and semi-quantitative assessment demonstrated superior sensitivity (96.7%) to visual assessment (p = 0.03) or semi-quantitative assessment (p = 0.003) alone with equal specificity. Visual and semi-quantitative assessments of 123I-FP-CIT SPECT are helpful for the diagnosis of dNDD, and combined visual and semi-quantitative assessment shows superior sensitivity with equal specificity.

Ethnic comparison of pharmacokinetics of (18)F-florbetaben, a PET tracer for beta-amyloid imaging, in healthy Caucasian and Japanese subjects.

PURPOSE: (18)F-Florbetaben is a positron emission tomography (PET) tracer indicated for imaging cerebral beta-amyloid deposition in adult patients with cognitive impairment who are being evaluated for Alzheimer's disease and other causes of cognitive decline. The present study examined ethnic comparability of the plasma pharmacokinetics, which is the input to the brain, between Caucasian and Japanese subjects. METHODS: Two identical phase I trials were performed in 18 German and 18 Japanese healthy volunteers to evaluate the plasma pharmacokinetics of a single dose of 300 MBq (18)F-florbetaben, either of low (≤5 µg, LD) or high (50-55 µg, HD) mass dose. Pharmacokinetic parameters were evaluated based on the total (18)F radioactivity measurements in plasma followed by metabolite analysis using radio-HPLC. RESULTS: The pharmacokinetics of (18)F-florbetaben was characterized by a rapid elimination from plasma. The dose-normalized areas under the curve of (18)F-florbetaben in plasma as an indicator of the input to the brain were comparable between Germans (LD: 0.38 min/l, HD: 0.55 min/l) and Japanese (LD: 0.35 min/l, HD: 0.45 min/l) suggesting ethnic similarity, and the mass dose effect was minimal. A polar metabolite fraction was the main radiolabelled degradation product in plasma and was also similar between the doses and the ethnic groups. CONCLUSION: Absence of a difference in the pharmacokinetics of (18)F-florbetaben in Germans and Japanese has warranted further global development of the PET imaging agent.

[A case of small bowel cancer with positive peritoneal cytology and five-year recurrence-free survival].

Small bowel cancer is frequently detected at an advanced stage and its prognosis is poor. We report on a patient with small bowel cancer with positive peritoneal cytology who survived for 5 years without recurrence after surgery.The case involved a 73-year-old woman who had undergone partial resection of the small intestine and lymphadenectomy for a small bowel tumor with obstruction. Pathological examination confirmed papillary adenocarcinoma with partial serosal invasion. Ascites cytology indicated a class V tumor. Adjuvant chemotherapy with TS-1 was administered for 20 months, and the patient has survived without evidence of disease for over 5 years.In this case, it is possible that TS-1 chemotherapy was effective for prevention against small bowel cancer recurrence.Furthermore , peritoneal cytology in patients with small bowel cancer should be evaluated as a predictor of prognosis.

[Accuracy of Injection Dose of Amyloid PET Agent Using Radiopharmaceutical Activity Suppliers].

PURPOSE: This study aimed to identify disposable items with low amyloid positron emission tomography (PET) agent radioactivity adsorption for accurate injections using a radiopharmaceutical activity supplier. METHODS: First, we investigated disposable items currently used for amyloid PET agent injection. Next, we measured the residual radioactivity rates of amyloid PET agents on three-way stopcocks, extension tubes, butterfly needles, and indwelling needles to identify disposable items with low radioactivity adsorption. Finally, we evaluated the accuracy of amyloid PET agent injection using the selected disposable items and a radiopharmaceutical activity supplier. RESULTS: The polybutadiene extension tube exhibited a significantly lower residual activity rate than that of the polyvinyl chloride extension tube. Similarly, the indwelling needles showed significantly lower residual activity rate than that of butterfly needles. The dose indicated by a radiopharmaceutical activity supplier was 184.1 MBq, while the dose calibrator measured the radioactivity which flowed into the vial as 170.2 MBq, resulting in an administration accuracy of 8.2%. CONCLUSION: To ensure accurate amyloid PET agent injections, we recommend using polybutadiene extension tubes and indwelling needles due to their lower radioactivity adsorption.

Regulatory effects of Spirulina complex polysaccharides on growth of murine RSV-M glioma cells through Toll-like receptor 4.

This study is the first to report that Spirulina complex polysaccharides (CPS) suppress glioma growth by down-regulating angiogenesis via a Toll-like receptor 4 signal. Murine RSV-M glioma cells were implanted s.c. into C3H/HeN mice and TLR4 mutant C3H/HeJ mice. Treatment with either Spirulina CPS or Escherichia coli (E. coli) lipopolysaccharides (LPS) strongly suppressed RSV-M glioma cell growth in C3H/HeN, but not C3H/HeJ, mice. Glioma cells stimulated production of interleukin (IL)-17 in both C3H/HeN and C3H/HeJ tumor-bearing mice. Treatment with E. coli LPS induced much greater IL-17 production in tumor-bearing C3H/HeN mice than in tumor-bearing C3H/HeJ mice. In C3H/HeN mice, treatment with Spirulina CPS suppressed growth of re-transplanted glioma; however, treatment with E. coli LPS did not, suggesting that Spirulina CPS enhance the immune response. Administration of anti-cluster of differentiation (CD)8, anti-CD4, anti-CD8 antibodies, and anti-asialo GM1 antibodies enhanced tumor growth, suggesting that T cells and natural killer cells or macrophages are involved in suppression of tumor growth by Spirulina CPS. Although anti-interferon-γ antibodies had no effect on glioma cell growth, anti-IL-17 antibodies administered four days after tumor transplantation suppressed growth similarly to treatment with Spirulina CPS. Less angiogenesis was observed in gliomas from Spirulina CPS-treated mice than in those from saline- or E. coli LPS-treated mice. These findings suggest that, in C3H/HeN mice, Spirulina CPS antagonize glioma cell growth by down-regulating angiogenesis, and that this down-regulation is mediated in part by regulating IL-17 production.

Evaluation of two- and three-dimensional visualization for endoscopic endonasal surgery using a novel stereoendoscopic system in a novice: a comparison on a dry laboratory model.

BACKGROUND: Three-dimensional (3-D) stereoscopic vision is theoretically superior to two-dimensional (2-D) vision in endoscopic endonasal surgery. However, only few reports have quantitatively compared endoscopic performance under the two visual conditions. We introduced a newly designed stereoendoscopic system with a "dual-lens and single camera" for endoscopic endonasal surgery and objectively compared the performances under 3-D and high-definition 2-D visualizations on a dry laboratory model. METHODS: Thirty subjects without experience performing endoscopic surgery, computer-simulated training or any 3-D video system were recruited and divided into two groups (Group A and Group B) for performing two different tasks. The novel 4.7-mm-diameter stereoendoscope provided high-definition (HD) images. In Task 1, Group A started the task under the 3-D condition followed by the 2-D condition, and Group B vice versa. In Task 2, Group A started the task under the 2-D condition followed by the 3-D condition, and Group B vice versa. The performance accuracy and speed under the two visual conditions were analyzed. RESULTS: Significant improvement in performance accuracy and speed was seen under 3-D conditions in the both "3-D first" and "2-D first" subgroups during both tasks (P < .001). Regardless of order, the inaccuracy rate and performance time under 3-D conditions was significantly lower than that under 2-D conditions in each subject. CONCLUSIONS: We demonstrated the advantage of 3-D visualization over 2-D visualization for inexperienced subjects. Further quantitative clinical studies are required to confirm whether stereoendoscopy actually provides benefits in clinical settings.

[Usefulness of nuclear medicine extension code keeping the integrity with JJ1017].

OBJECTIVE: Working group on JJ1017 nuclear medicine domain extension code in the Japanese Society of Nuclear Medicine has created nuclear medicine extension codes keeping the integrity with JJ1017. The objective of this study was to investigate the usefulness of nuclear medicine extension codes in real clinical settings. METHOD: Nuclear medicine examinations of each institution were extracted from the examination master table and then the target subset of examinations to be coded with JJ1017 were identified. For this subset, working process was conducted, during which the followings compared conformity rate, application rate of representative frequently code set and compliance rate of nuclear medicine extension codes. RESULTS: Without using representative frequently code set, it was difficult to invent the same code for the same examination. By using the representative frequently code set, the same code expression could be invented for the same examination. Furthermore, using nuclear medicine extension codes additionally, these which could not be appropriately coded with representative frequently code set alone. CONCLUSION: Nuclear medicine extension codes keeping the integrity with JJ1017, was proved to be useful to improve the accuracy of coding.

Dosimetry and efficacy of a tau PET tracer [18F]MK-6240 in Japanese healthy elderly and patients with Alzheimer's disease.

OBJECTIVE: A new tau PET tracer [18F]MK-6240 has been developed; however, its dosimetry and pharmacokinetics have been published only for a European population. This study investigated the safety, radiation dosimetry, pharmacokinetics and biodistribution of [18F]MK-6240 in Japanese elderly subjects. Also, the pattern and extent of brain retention of [18F]MK-6240 in Japanese healthy elderly subjects and patients with Alzheimer's disease (AD) were investigated. These Japanese results were compared with previous reports on non-Japanese. METHODS: Three healthy elderly subjects and three AD patients were enrolled. Dynamic whole-body PET scans were acquired for up to 232 min after starting injection of [18F]MK-6240 (370.4 ± 27.0 MBq) for the former, while a dynamic brain scan was performed from 0 to 75 min post injection for the latter. For both groups, brain PET scans were conducted from 90 to 110 min post injection. Sequential venous blood sampling was performed to measure the radioactivity concentration in the whole blood and plasma as well as the percentages of parent [18F]MK-6240 and radioactive metabolites in plasma. Organ doses and effective doses were estimated using the OLINDA Ver.2 software. Standardized uptake value ratios (SUVRs) and distribution volume ratios (DVRs) by Logan reference tissue model (LRTM) were measured in eight brain regions using the cerebellar cortex as the reference. Blood tests, urine analysis, vital signs and electrocardiography were performed for safety assessments. RESULTS: No adverse events were observed. The highest radiation doses were received by the gallbladder (257.7 ± 74.9 µGy/MBq) and the urinary bladder (127.3 ± 11.7 µGy/MBq). The effective dose was 26.8 ± 1.4 µSv/MBq. The parent form ([18F]MK-6240) was metabolized quickly and was less than 15% by 35 min post injection. While no obvious accumulation was found in the brain of healthy subjects, focal accumulation of [18F]MK-6240 was observed in the cerebral cortex of AD patients. Regional SUVRs of the focal lesions in AD patients increased gradually over time, and the difference of SUVRs between healthy subjects and AD patients became large and stable at 90 min after injection. High correlations of SUVR and DVR were observed (p < 0.01). CONCLUSION: The findings supported safety and efficacy of [18F]MK-6240 as a tau PET tracer for Japanese populations. Even though the number of subjects was limited, the radiation dosimetry profiles, pharmacokinetics, and biodistribution of [18F]MK-6240 were consistent with those for non-Japanese populations. TRIAL REGISTRATION: Japan Pharmaceutical Information Center ID, JapicCTI-194972.

Involvement of Akt/NF-κB pathway in antitumor effects of parthenolide on glioblastoma cells in vitro and in vivo.

BACKGROUND: Glioblastoma is the most common and most aggressive form of malignant glioma and is very difficult to treat. Controlling tumour cell invasion and angiogenesis is essential to improve the prognosis of glioblastoma patients. Since constitutive activation of nuclear factor-κB (NF-κB) is necessary for tumour progression, NF-κB may be an important pharmacological target for this disease. Our study aimed to evaluate the antitumour effects of parthenolide, a NF-κB inhibitor, in two human glioblastoma cell lines (U87MG and U373) and in glioblastoma xenografts. Furthermore, we aimed to investigate the molecular mechanisms underlying these effects. METHODS: The anti-invasive and anti-angiogenic effects of parthenolide were analysed using in vitro invasion and angiogenesis assays. Parthenolide-induced growth inhibition of glioblastoma cells in vitro was determined using the MTT (methyl thiazolyl tetrazolium) assay. In addition, the effect of parthenolide on orthotropic implantation in vivo was evaluated using an intracerebral human glioblastoma xenograft model. RESULTS: We found that parthenolide suppresses proliferation, invasion, and tumour- induced angiogenesis of glioblastoma cells. Molecular studies demonstrated that parthenolide suppresses gene and protein expression of angiogenic factors. Furthermore, parthenolide reduced Akt phosphorylation and activated mitochondrial signalling, suggesting that the antitumour function of parthenolide may be mediated not only by the inhibition of NF-κB but also by the inhibition of Akt signalling and the activation of apoptotic proteins. Parthenolide suppressed neovascularity and tumour growth in glioblastoma xenografts. CONCLUSION: The present study identified parthenolide as a new therapeutic agent for glioblastomas.

Stereoscopic virtual realistic surgical simulation in intracranial aneurysms.

BACKGROUND: Three-dimensional (3D)-computed tomographic angiography (CTA) has been widely used for surgical simulation of intracranial aneurysms. Stereo imaging technology is progressing rapidly in recent years and stereo imaging may make more realistic surgical simulation possible. Therefore, we aimed at the establishment of a technique for stereoscopic viewing of minute volume rendering images while pursuing a low cost. MATERIALS AND METHODS: Between January 2009 and June 2011, 54 patients with ruptured intracranial aneurysms were enrolled in this study. CTA data was transferred to the workstation equipped with image-processing software, and multilayer fusion images were processed by neurosurgeons. Image data for stereoscopic viewing of multilayer fusion image from arbitrary directions were collected form rotational trajectories around an aneurysm and were output to MPEG file. Stereoscopic viewing using MPEG data was achieved by the freeware named Stereo Movie Maker. Stereo viewing method using QuickTime VR format was also tried. RESULTS: Multilayer fusion image created from CTA data displayed clearly the anatomical information about not only the aneurysm but also the surrounding structures, such as parent artery, venous system, brain tissue, skull bone, and scalp. The quality of the resulting multilayer fusion image was suitable for surgical simulation with virtual reality. Virtual realistic surgical simulation became possible by the combination of minute multilayer fusion image and stereoscopic viewing by our method. CONCLUSIONS: Our method for stereo viewing of multilayer fusion images resulted in an improvement in the capability of diagnostic imaging and the image-guided support for neurosurgical procedures in intracranial aneurysm.

HA1077, a Rho kinase inhibitor, suppresses glioma-induced angiogenesis by targeting the Rho-ROCK and the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) signal pathways.

Malignant gliomas are characterized by high invasive potential and strong angiogenic ability. Constitutive activation of Rho and its downstream target Rho-kinase are crucial for tumor progression. We investigated the effect of the Rho-kinase inhibitor HA1077 on tumor-induced angiogenesis of malignant glioma cells and explored the molecular mechanisms underlying the effect of HA1077. Here, we demonstrated that HA1077 suppressed tube formation of endothelial cells in human umbilical vein endothelial cell (HUVEC)-glioma cell co-culture assay. Western blot, RT-PCR, ELISA and zymography demonstrated that HA1077 suppressed gene and protein expressions of vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2 and MMP-9 in glioma cells. Furthermore, HA1077 attenuated the phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and the DNA binding activity of activator protein-1, a key downstream transcriptional factor of ERK1/2. HA1077 also suppressed the migration of HUVEC in vitro. Thus, it is suggested that the anti-angiogenic effect of HA1077 may be due to the combination of ROCK inhibition and mitogen-activated protein kinase kinase (MEK)/ERK pathway inhibition. Moreover, an in vivo intracerebral human glioma cell xenograft mouse model demonstrated that HA1077 suppressed neovascularity and tumor growth. The results of the present study suggest that HA1077 has a therapeutic potential as an anti-angiogenic agent against malignant gliomas.

Identification and functional characterization of glioma-specific promoters and their application in suicide gene therapy.

Suicide gene therapy has been shown to be effective in inducing tumor regression. In this study, a human brain tumor-specific promoter was identified and used to develop transcriptionally targeted gene therapy. We searched for genes with brain tumor-specific expression. By in silico and reverse-transcription polymerase chain reaction screening, MAGE-A3 and SSX4 were found to be expressed in a tumor-specific manner. SSX4 gene promoter activity was high in human brain tumor cells but not in normal human astrocyte cells, whereas the MAGE-A3 promoter showed activity in both tumor and normal cells. A retrovirus vector carrying a suicide gene, the herpes simplex virus thymidine kinase gene controlled by the SSX4 promoter, was constructed to evaluate the efficacy of the promoter in tumor-specific gene therapy. Glioma and human telomerase catalytic subunit-immortalized fibroblast BJ-5ta cell lines transduced with retrovirus vectors were assayed for killing activity by ganciclovir. Glioma cell lines were effectively killed by ganciclovir in a concentration-dependent manner, whereas BJ-5ta cells were not. By contrast, MAGE-A3 promoter failed to induce cytotoxicity in a brain tumor-specific manner. In addition, mouse glioma RSV-M cells transduced with retrovirus vector also showed suppressed tumor formation activity in syngeneic mice in response to ganciclovir administration. Therefore, the SSX4 promoter is a candidate for brain tumor-specific gene therapy and supports the efficacy and safety of suicide gene therapy for malignant brain tumors.

Sea-blue histiocytosis in a patient with acute myeloid leukemia with myelodysplasia-related changes harboring isolated trisomy 9: pathognomonic or a coincidence?

Although isolated trisomy 9, a form of chromosome aneuploidy, is rare in acute myeloid leukemia (AML), up to 30 cases of AML involving isolated trisomy 9 have been reported to date. We report the case of a 77-year-old female with AML, in which trisomy 9 was detected as an isolated aberration. In addition, the patient's bone marrow displayed so-called sea-blue histiocytosis. The accumulation of further cases of isolated trisomy 9-harboring AML involving sea-blue histiocytosis is necessary to determine whether the coexistence of these findings is pathognomonic or a coincidence.

Enhanced expression of cancer testis antigen genes in glioma stem cells.

Cancer stem cells are an important target for effective therapy, since they show tumorigenicity, chemoresistance, and radioresistance. We isolated cancer stem cells from glioma cell lines and tissues and examined the expression of cancer testis antigen (CTA) genes as potential target molecules for cancer vaccine therapy. CTA genes were highly and frequently expressed in cancer stem cells compared with differentiated cells. In addition, histone acetylation levels in the promoter regions of CTA genes were high in cancer stem cells and low in differentiated cells, while DNA methylation analysis of the promoter regions revealed hypomethylation in cancer stem cells. This epigenetic difference between cells leads to heterogeneous expression of CTA genes in the tumor mass, which consists of cells at various levels of differentiation. Moreover, the expression level of HLA class I antigens was not affected by the differentiation status, suggesting that CTA genes may present as surface antigens in cancer stem cells. Taken together, these findings suggest that CTA genes may be attractive candidates for targeted vaccine therapy against cancer stem cells in glioma patients.

Anti-invasive and antiangiogenic effects of MMI-166 on malignant glioma cells.

BACKGROUND: The constitutive overexpression of matrix metalloproteinases (MMPs) is frequently observed in malignant tumours. In particular, MMP-2 and MMP-9 have been reported to be closely associated with invasion and angiogenesis in malignant gliomas. Our study aimed to evaluate the antitumour effects of MMI-166 (Nalpha-[4-(2-Phenyl-2H- tetrazole-5-yl) phenyl sulfonyl]-D-tryptophan), a third generation MMP inhibitor, on three human glioma cell lines (T98G, U87MG, and ONS12) in vitro and in vivo. METHODS: The effects of MMI-166 on the gelatinolytic activity was analysed by gelatine zymography. The anti-invasive effect of MMI-166 was analysed by an in vitro invasion assay. An in vitro angiogenesis assay was also performed. In vitro growth inhibition of glioma cells by MMI-166 was determined by the MTT assay. The effect of MMI-166 on an orthotropic implantation model using athymic mice was also evaluated. RESULTS: Gelatine zymography revealed that MMP-2 and MMP-9 activities were suppressed by MMI-166. The invasion of glioma cells was suppressed by MMI-166. The angiogenesis assay showed that MMI-166 had a suppressive effect on glioma cell-induced angiogenesis. However, MMI-166 did not suppress glioma cell proliferation in the MTT assay. In vivo, MMI-166 suppressed tumour growth in athymic mice implanted orthotropically with T98G cells and showed an inhibitory effect on tumour-induced angiogenesis and tumour growth. This is the first report of the effect of a third generation MMP inhibitor on malignant glioma cells. CONCLUSIONS: These results suggest that MMI-166 may have potentially suppressive effects on the invasion and angiogenesis of malignant gliomas.