Chloroethylating nitrosoureas in cancer therapy: DNA damage, repair and cell death signaling.

Chloroethylating nitrosoureas (CNU), such as lomustine, nimustine, semustine, carmustine and fotemustine are used for the treatment of malignant gliomas, brain metastases of different origin, melanomas and Hodgkin disease. They alkylate the DNA bases and give rise to the formation of monoadducts and subsequently interstrand crosslinks (ICL). ICL are critical cytotoxic DNA lesions that link the DNA strands covalently and block DNA replication and transcription. As a result, S phase progression is inhibited and cells are triggered to undergo apoptosis and necrosis, which both contribute to the effectiveness of CNU-based cancer therapy. However, tumor cells resist chemotherapy through the repair of CNU-induced DNA damage. The suicide enzyme O6-methylguanine-DNA methyltransferase (MGMT) removes the precursor DNA lesion O6-chloroethylguanine prior to its conversion into ICL. In cells lacking MGMT, the formed ICL evoke complex enzymatic networks to accomplish their removal. Here we discuss the mechanism of ICL repair as a survival strategy of healthy and cancer cells and DNA damage signaling as a mechanism contributing to CNU-induced cell death. We also discuss therapeutic implications and strategies based on sequential and simultaneous treatment with CNU and the methylating drug temozolomide.

The role of sphingosine kinase isoforms and receptors S1P1, S1P2, S1P3, and S1P5 in primary, secondary, and recurrent glioblastomas.

Sphingosine-1-phosphate (S1P), the corresponding kinases SphK1-2, and receptors S1P1-3 and S1P5 are involved in cell survival and growth. Pathway components are overexpressed in many tumors including glioblastoma. Previous studies showed that the expression of SphK1 influenced survival of glioblastoma patients, yet the roles of SphK1-2 and receptors S1P1-3 and S1P5 have not been investigated in different forms of glioblastoma. Samples from 59 patients (37 males, 22 females, age 55.1 ± 17.1 years) suffering from primary (n = 35), recurrent (n = 18), and secondary (n = 6) glioblastomas were analyzed using quantitative real-time PCR and immunohistochemistry for expression levels of SphK1 and SphK2 and S1P1-3 and S1P5. Sixteen autopsy nontumorous brain specimens were used as controls. Expression data was correlated with clinical data and patient survival. All markers were overexpressed in the glioblastoma specimens compared to the non-neoplastic brain tissue. SphK1 and all S1P receptors were expressed in increasing order of magnitude from primary, up to recurrent and secondary glioblastomas, with values of up to 44-fold compared to normal brain tissue. In contrast, SphK2 levels were highest in primary tumors (25-fold). Expression of the sphingosine signaling pathway components was influenced by radio/radiochemotherapy in distinct ways. Immunohistochemistry for SphK1 and S1P1 confirmed the overexpression in glioblastoma. Uni- and multivariate survival analyses identified S1P5 messenger RNA levels as an independent prognostic factor of survival. The sphingosine pathway is overexpressed in glioma. Its components show distinct expression patterns in the tumor subgroups. S1P5 is identified as an independent prognostic factor in multivariate analysis, and this pathway promises to be a candidate for targeted therapies.

Management options for established chemotherapy-induced peripheral neuropathy.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating condition associated with a variety of chemotherapeutic agents. Clinicians are cognizant of the negative impact of CIPN on cancer treatment outcomes and patients' psychosocial functioning and quality of life. In an attempt to alleviate this problem, clinicians and patients try various therapeutic interventions, despite limited evidence to support efficacy of these treatments. The rationale for such use is mostly based on the evidence for the treatment options in non-CIPN peripheral neuropathy syndromes, as this area is more robustly studied than is CIPN treatment. In this manuscript, we examine the existing evidence for both CIPN and non-CIPN treatments and develop a summary of the best available evidence with the aim of developing a practical approach to the treatment of CIPN, based on available literature and clinical practice experience.

Cerebrospinal fluid ferritin--unspecific and unsuitable for disease monitoring.

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage is sometimes difficult to diagnose radiologically. Cerebrospinal fluid (CSF) ferritin has been proposed to be highly specific and sensitive to detect hemorrhagic central nervous system (CNS) disease. We analyzed here the specificity of CSF ferritin in a large series of various CNS diseases and the influence of serum ferritin. MATERIALS AND METHODS: CSF ferritin, lactate, protein and total cell count were analyzed in 141 samples: neoplastic meningitis (n=62), subarachnoid hemorrhage (n=20), pyogenic infection (n=10), viral infection (n=10), multiple sclerosis (n=10), borreliosis (n=5) and normal controls (n=24). Cerebrospinal fluid ferritin was measured with a microparticle immunoassay. In addition, serum and CSF ferritin were compared in 18 samples of bacterial and neoplastic meningitis. RESULTS: In CNS hemorrhage, median ferritin was 51.55µg/L (sensitivity: 90%) after the second lumbar puncture. In neoplastic meningitis, the median CSF ferritin was 16.3µg/L (sensitivity: 45%). Interestingly, ferritin was higher in solid tumors than that in hematological neoplasms. In 90% of pyogenic inflammation, ferritin was elevated with a median of 53.35µg/L, while only 50% of patients with viral infection had elevated CSF ferritin. In ventricular CSF, median ferritin was 163µg/L, but only 20.6µg/L in lumbar CSF. Ferritin was normal in multiple sclerosis and borreliosis. CONCLUSIONS: Ferritin was elevated not only in hemorrhagic disease, but also in neoplastic and infectious meningitis. Ferritin was not a reliable marker of the course of disease. The influence of serum ferritin on CSF ferritin is negligible. We conclude that elevated CSF ferritin reliably, but unspecifically indicates severe CNS disease.

Artesunate in glioblastoma therapy: Case reports and review of clinical studies.

BACKGROUND: Artesunate, a derivative of the active ingredient artemisinin from Artemisia annua L. used for centuries in the traditional Chinese medicine, is being applied as front-line drug in malaria treatment. As it is cytotoxic for cancer cells, trials are ongoing to include this drug as supplement in cancer therapy. In glioblastoma cells, artesunate was shown to induce oxidative stress, DNA base damage and double-strand breaks (DSBs), apoptosis, and necroptosis. It also inhibits DNA repair functions and bears senolytic activity. Compared to ionizing radiation, DNA damages accumulate over the whole exposure period, which makes the agent unique in its genotoxic profile. Artesunate has been used in adjuvant therapy of various cancers. PURPOSE: As artesunate has been used in adjuvant therapy of different types of cancer and clinical trials are lacking in brain cancer, we investigated its activity in glioma patients with focus on possible side effects. STUDY DESIGN: Between 2014 and 2020, twelve patients were treated with artesunate for relapsing glioma and analyzed retrospectively: 8 males and 4 females, median age 45 years. HISTOLOGY: 4 glioblastomas WHO grade 4, 5 astrocytomas WHO grade 3, 3 oligodendrogliomas grade 2 or 3. All patients were pretreated with radiation and temozolomide-based chemotherapy. Artesunate 100 mg was applied twice daily p.o. combined with dose-dense temozolomide alone (100 mg/m2 day 1-5/7, 10 patients) or with temozolomide (50 mg/m2 day 1-5/7) plus lomustine (CCNU, 40 mg day 6/7). Blood count, C-reactive protein (CRP), liver enzymes, and renal parameters were monitored weekly. RESULTS: Apart from one transient grade 3 hematological toxicity, artesunate was well tolerated. No liver toxicity was observed. While 8 patients with late stage of the disease had a median survival of 5 months after initiation of artesunate treatment, 4 patients with treatment for remission maintenance showed a median survival of 46 months. We also review clinical trials that have been performed in other cancers where artesunate was included in the treatment regimen. CONCLUSIONS: Artesunate administered at a dose of 2 × 100 mg/day was without harmful side effects, even if combined with alkylating agents used in glioma therapy. Thus, the phytochemical, which is also utilized as food supplement, is an interesting, well tolerated supportive agent useful for long-term maintenance treatment. Being itself cytotoxic on glioblastoma cells and enhancing the cytotoxicity of temozolomide as well as in view of its senolytic activity, artesunate has clearly a potential to enhance the efficacy of malignant brain cancer therapy.

Temozolomide dosing regimens for glioma patients.

Even in modern times of high-precision brain surgery and irradiation, malignant gliomas belong to the deadliest types of cancer. Due to a marked primary and presumably also acquired resistance, the beneficial effects of cytotoxic chemotherapy are limited. Only one randomized clinical trial demonstrated a significant impact on overall survival with temozolomide. Ever since, there have been attempts to improve the efficacy of alkylating chemotherapy by modulating the distribution of dose in time aiming at a better treatment success. Apart from higher cumulative doses per cycle, better efficacy by depletion of the anti-alkylating O6-methylguanine-DNA methyltransferase (MGMT) protein has been a major goal of these regimens. After promising results of single-arm pilot studies, however, randomized studies have been disappointing so far. In this overview, the different strategies of dose-dense temozolomide regimen are highlighted and results of clinical trials put into perspective.

Temozolomide - Just a Radiosensitizer?

Radiation concomitant with the DNA methylating drug temozolomide (TMZ) is the gold standard in the treatment of glioblastoma. In this adjuvant setting, TMZ is regarded to be a radiation sensitizer. However, similar to ionising radiation, TMZ induces DNA double-strand breaks and is itself a potent trigger of apoptosis, cellular senescence and autophagy, suggesting that radiation and TMZ act independently. Although cell culture experiments yielded heterogeneous results, some data indicate that the cytotoxic effect of radiation was only enhanced when TMZ was given before radiation treatment. Based on the molecular mechanism of action of TMZ, the importance of specific TMZ and radiation-induced DNA lesions, their repair as well as their interactions, possible scenarios for an additive or synergistic effect of TMZ and radiation are discussed, and suggestions for an optimal timing of radio-chemical treatments are proposed.

The Emesis Trial: Depressive Glioma Patients Are More Affected by Chemotherapy-Induced Nausea and Vomiting.

PURPOSE: Glioma patients face a limited life expectancy and at the same time, they suffer from afflicting symptoms and undesired effects of tumor treatment. Apart from bone marrow suppression, standard chemotherapy with temozolomide causes nausea, emesis and loss of appetite. In this pilot study, we investigated how chemotherapy-induced nausea and vomiting (CINV) affects the patients' levels of depression and their quality of life. METHODS: In this prospective observational multicentre study (n = 87), nausea, emesis and loss of appetite were evaluated with an expanded MASCC questionnaire, covering 10 days during the first and the second cycle of chemotherapy. Quality of life was assessed with the EORTC QLQ-C30 and BN 20 questionnaire and levels of depression with the PHQ-9 inventory before and after the first and second cycle of chemotherapy. RESULTS: CINV affected a minor part of patients. If present, it reached its maximum at day 3 and decreased to baseline level not before day 8. Levels of depression increased significantly after the first cycle of chemotherapy, but decreased during the further course of treatment. Patients with higher levels of depression were more severely affected by CINV and showed a lower quality of life through all time-points. CONCLUSION: We conclude that symptoms of depression should be perceived in advance and treated in order to avoid more severe side effects of tumor treatment. Additionally, in affected patients, delayed nausea was most prominent, pointing toward an activation of the NK1 receptor. We conclude that long acting antiemetics are necessary totreat temozolomide-induced nausea.

Role of macrophage migration inhibitory factor in primary glioblastoma multiforme cells.

Macrophage migration inhibitory factor (MIF) is a protein that is overexpressed in many tumors, such as colon and prostate cancer, melanoma, and glioblastoma multiforme (GBM). In its function as a cytokine, MIF induces angiogenesis, promotes cell cycle progression, and inhibits apoptosis. Recently, the molecular signal transduction has been specified: MIF has been found to be a ligand to the CD74/CD44-receptor complex and to activate the ERK1/2 MAPK cascade. In addition MIF binds to the chemokine receptors CXCR2 and CXCR4. This effects an integrin-dependent leukocyte arrest and mediates leukocyte chemotaxis. Recent work has described a clearer role of MIF in GBM tumor cell lines. The current study used human primary GBM cells. We show that inhibition of MIF with ISO-1, an inhibitor of the D-dopachrome tautomerase site of MIF, reduced the growth rate of primary GBM cells in a dose-dependent manner, and in addition ISO-1 increased protein expression of MIF and its receptors CD74, CXCR2, and CXCR4 in vitro but decreased expression of CD44. Furthermore, hypoxia as cell stressor increases the protein expression of MIF in primary GBM cells. These results underscore the importance of MIF in GBM and show that MIF and its receptors may be a promising target for the treatment of malignant gliomas.

Why Do Our Cancer Patients Sleep So Badly? Sleep Disorders in Cancer Patients: A Frequent Symptom with Multiple Causes.

INTRODUCTION: On the one hand, sleep disorders in cancer patients are reported in 30-50% of cancer patients. On the other hand, specific causes for these sleep disorders are little known. This study was done to evaluate factors which may affect sleep of cancer patients. To our knowledge, this is the first study which includes return to work as one factor of sleep disturbance. METHODS: 107 patients with various types of cancer treated in 2 hospitals were interviewed with a battery of questionnaires after having given informed consent. The questionnaires intended to detect abnormalities of sleep and related pain, breathing disorders, restless legs syndrome, depression, rumination, medication, and psychosocial distress. The study was approved by the ethics committee of the University of Marburg. RESULTS: The analysis of the 6 sleep-related questionnaires indicated a sleep disorder of any kind in 68% of all patients. Insomnia symptoms were present in 48 patients (44.9%). Pain, depression, anxiety, and worries about the workplace were significantly related to sleep disorders. CONCLUSION: Sleep disorders are common in cancer patients. The causes are manifold and should be considered by caregivers during diagnosis, therapy, and aftercare of cancer patients. Tumour patients should actively be asked about sleep disorders. If these are present, they should be addressed, and as they have a large impact on quality of life, treatment options should be offered in cooperation with sleep specialists.

Reduced cortisol levels in cerebrospinal fluid and differential distribution of 11beta-hydroxysteroid dehydrogenases in multiple sclerosis: implications for lesion pathogenesis.

Relapses during multiple sclerosis (MS) are treated by administration of exogenous corticosteroids. However, little is known about the bioavailability of endogenous steroids in the central nervous system (CNS) of MS patients. We thus determined cortisol and dehydroepiandrosterone (DHEA) levels in serum and cerebrospinal fluid (CSF) samples from 34 MS patients, 28 patients with non-inflammatory neurological diseases (NIND) and 16 patients with other inflammatory neurological diseases (OIND). This revealed that MS patients - in sharp contrast to patients with OIND - show normal cortisol concentrations in serum and lowered cortisol levels in the CSF during acute relapses. This local cortisol deficit may relate to poor local activation of cortisone via 11beta-hydroxysteroid dehydrogenase type 1 (11bHSD1) or to inactivation via 11bHSD2. Accordingly, 11bHSD2 was found to be expressed within active plaques, whereas 11bHSD1 was predominantly detected in surrounding "foamy" macrophages. Our study thus provides new insights into the impaired endogenous CNS cortisol regulation in MS patients and its possible relation to MS lesion pathogenesis. Moreover, an observed upregulation of 11bHSD1 in myelin-loaded macrophages in vitro suggests an intriguing hypothesis for the self-limiting nature of MS lesion development. Finally, our findings provide an attractive explanation for the effectivity of high- vs. low-dose exogenous corticosteroids in the therapy of acute relapses.

The role of cytotoxic drugs in the treatment of central nervous system gliomas.

Gliomas are the mostfrequent subtype of primary brain tumors. They are lethal tumors, characterized by diffuse infiltration of the brain and a high resistance to conventional cancer therapies. Following maximal neurosurgical resection, bound to the limits of acceptable neurological sequelae, immediate post-operative radiotherapy is indicated in the majority of patients. Chemotherapy with the alkylating agent temozolomide, administered daily concomitantly to radiotherapy, and followed by six adjuvant monthly cycles, significantly improves the survival of newly diagnosed glioblastoma patients and has become the standard of care. Temozolomide is also the most often used chemotherapeutic treatment for recurrent low-grade and anaplastic gliomas after initial surgery and irradiation. The potential role of postoperative temozolomide in the first line treatment for low-grade and anaplastic glioma is currently under investigation in phase III trials. After failure of temozolomide, there is only limited activity of any other cytotoxic agent and the benefit of such second line therapy seems to be limited to a small subgroup of patients with the most chemosensitive gliomas. Abnormal hypermethylation of the promoter of the MGMT gene has been correlated with the response of glioma to alkylating chemotherapy. The loss of chromosomal arms 1p and 19q are genetic markers characteristic for gliomas with oligodendroglial differentiation which are also most sensitive to treatment. The predictive and prognostic value of these molecular markers is currently being determined prospectively in phase III studies. Anti-angiogenic agents and targeted receptor tyrosine kinase inhibitors are new pharmacological classes with activity against malignant gliomas. Phase III clinical studies evaluating combinations of these new agents with classical cytotoxic agents in first and in second line have recently been initiated.

Untreated glioblastoma multiforme: increased myo-inositol and glutamine levels in the contralateral cerebral hemisphere at proton MR spectroscopy.

PURPOSE: To use localized in vivo proton magnetic resonance (MR) spectroscopy of the contralateral hemisphere in patients with glioblastoma multiforme (GBM) to detect alterations in cerebral metabolites as potential markers of infiltrating GBM cells. MATERIALS AND METHODS: The study was approved by the ethics committee, and written informed consent was obtained. Twenty-two patients with newly diagnosed and untreated GBM underwent in vivo single-voxel short echo time proton MR spectroscopy with a 3-T MR imaging system. Absolute metabolite concentrations in the hemisphere contralateral to the tumor were compared with data from five patients with low-grade gliomas (LGGs) and from a group of 14 age-matched control subjects by using analysis of variance and subsequent t tests or corresponding nonparametric tests. RESULTS: In the contralateral hemisphere, MR spectroscopy revealed increased concentrations of myo-inositol and glutamine. Mean myo-inositol levels were significantly increased in patients with GBM (3.6 mmol/L +/- 0.8 [standard deviation]) relative to levels in control subjects (3.1 mmol/L +/- 0.6; P = .03) and tended to be higher relative to levels in patients with LGG (2.7 mmol/L +/- 0.8; P = .09). Mean glutamine concentrations in patients with GBM (3.4 mmol/L +/- 0.9) differed significantly from those in control subjects (2.7 mmol/L +/- 0.7; P = .01); mean concentrations in patients with GBM differed from those in patients with LGG (2.4 mmol/L +/- 0.5; P = .01). There were no significant differences between data in patients with LGG and in control subjects. CONCLUSION: Increased concentrations of myo-inositol and glutamine in the contralateral normal-appearing white matter of GBM patients are consistent with mild astrocytosis and suggest the detectability of early neoplastic infiltration by using proton MR spectroscopy in vivo.

Galectin-1 expression in human glioma cells: modulation by ionizing radiation and effects on tumor cell proliferation and migration.

Galectins are evolutionarily conserved beta-galactoside-binding lectins which recognize specific glycoconjugates on the cell surface and the extracellular matrix. Accumulating evidence indicates that these proteins are involved in a variety of physiological and pathological processes including tumor growth and metastasis. Up-regulated expression of galectin-1 is a hallmark of a variety of malignant tumors. Here, we examined the expression of galectin-1 in glioma cell lines, the influence of ionizing irradiation and the intracellular and extracellular effects of this protein on tumor cell proliferation and migration. Galectin-1 was detected in both A172 and U118 glioma cells by immunoblot analysis. Ionizing irradiation induced a statistically significant up-regulation in glioma cell lines. RNA-interference-mediated silencing resulted in a significant suppression of the proliferation of the A172 cells, while the addition of recombinant galectin-1 had no effect. On the other hand, the migratory capacity of both cell lines was reduced after galectin-1 down-regulation, and up-regulated by the addition of exogenous galectin-1. Our results provide evidence of a role for galectin-1 in the regulation of glioma cell proliferation and migration. While an intracellular mechanism seemed to prevail in galectin-1-mediated regulation of tumor cell proliferation, the control of cell migration was exerted by both intracellular and extracellular mechanisms. In addition, this protein was up-regulated by ionizing radiation, indicating that the blockade of this protein should be performed before radiotherapy to avoid any undesired stimulating effects. Given the multifactorial role of galectin-1 in the regulation of tumor escape and metastasis, we conclude that targeting galectin-1 may have therapeutic benefits in the treatment of malignant glioma.

Profiling of metalloprotease activities in cerebrospinal fluids of patients with neoplastic meningitis.

BACKGROUND: Neoplastic invasion into leptomeninges and subarachnoid space, resulting in neoplastic meningitis (NM) is a fatal complication of advanced solid and hematological neoplasms. Identification of malignant involvement of the cerebrospinal fluid (CSF) early in the disease course has crucial prognostic and therapeutic implications, but remains challenging. As indicators of extracellular matrix (ECM) degradation and breakdown of the blood-brain-barrier, Matrix Metalloproteases (MMPs) and A Disintegrin and Metalloproteases (ADAMs) are potential analytes for cerebral pathophysiology and metastatic dissemination of tumor cells into the CSF. METHODS: We compared protease activities in CSF samples from patients with NM and control individuals using FRET-based metalloprotease substrates with distinct enzyme selectivity profiles in a real-time, multiplex approach termed "proteolytic activity matrix assay" (PrAMA). Protease activity dynamics can be tracked by fluorescence changes over time. By simultaneously monitoring a panel of 5 FRET-substrate cleavages, a proteolytic signature can be identified and analyzed to infer the activities of multiple specific proteases. Distinct patterns of substrate cleavage comparing disease vs. control samples allow rapid, reproducible and sensitive discrimination even in small volumes of CSF. RESULTS: Individual substrate cleavage rates were linked to distinct proteases, and PrAMA computational inference implied increased activities of MMP-9, ADAM8 and ADAM17 (4-5-fold on average) in CSF samples from NM patients that were inhibitable by the metalloprotease inhibitor batimastat (BB-94). The activities of these proteases correlated with blood-brain barrier impairment. Notably, CSF cell counts were not found to directly reflect the protease activities observed in CSF samples from NM patients; this may explain the frequent clinical observation of negative cytology in NM patients. CONCLUSION: PrAMA analysis of CSF samples is a potential diagnostic method for sensitive detection of NM and may be suitable for the clinical routine.

Models of monocytic invasion into glioma cell aggregates.

BACKGROUND: In order to investigate why human gliomas are abundantly infiltrated by monocytic cells without signs of antitumor activity, experimental models were established in vitro and in vivo. MATERIALS AND METHODS: Peripheral human blood monocytes were added to A172 or U118 glioma cell spheroids and probes analyzed after 72 h by immunohistochemistry. Fluorescence-labelled peritoneal macrophages were administered to syngeneic RG2-glioma-bearing Fischer rats by intravenous or intracarotid injection. RESULTS: Spheroids of both cell lines were infiltrated by monocytes, which took on a chronic inflammatory phenotype with co-expression of MRP8 and MAC 387/MRP14 and positivity to 25F9, but not to 27E10. After both intra-arterial and intravenous injection, labelled monocytes accumulated within the tumor parenchyma of the rat gliomas, while the surrounding brain was only sparsely infiltrated. CONCLUSION: The experimental models described here allow for further investigation of the interactions between monocytes and glioma cells, both in vitro and in vivo. Moreover, monocytes that infiltrate from the peripheral blood into brain tumors may serve as carriers for targeted therapies.

The metalloprotease-disintegrin ADAM8 contributes to temozolomide chemoresistance and enhanced invasiveness of human glioblastoma cells.

BACKGROUND: Despite multimodal treatment, glioblastoma (GBM) therapy with temozolomide (TMZ) remains inefficient due to chemoresistance. Matrix metalloproteinase (MMP) and a disintegrin and metalloprotease (ADAM), increased in GBM, could contribute to chemoresistance and TMZ-induced recurrence of glioblastoma. METHODS: TMZ inducibility of metalloproteases was determined in GBM cell lines, primary GBM cells, and tissues from GBM and recurrent GBM. TMZ sensitivity and invasiveness of GBM cells were assessed in the presence of the metalloprotease inhibitors batimastat (BB-94) and marimastat (BB-2516). Metalloprotease-dependent effects of TMZ on mitochondria and pAkt/phosphatidylinositol-3 kinase (PI3K) and phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) pathways were analyzed by fluorescence activated cell sorting, morphometry, and immunoblotting. Invasiveness of GBM cells was determined by Matrigel invasion assays. Potential metalloprotease substrates were identified by proteomics and tested for invasion using blocking antibodies. RESULTS: TMZ induces expression of MMP-1, -9, -14, and ADAM8 in GBM cells and in recurrent GBM tissues. BB-94, but not BB-2516 (ADAM8-sparing) increased TMZ sensitivity of TMZ-resistant and -nonresistant GBM cells with different O(6)-methylguanine-DNA methyltransferase states, suggesting that ADAM8 mediates chemoresistance, which was confirmed by ADAM8 knockdown, ADAM8 overexpression, or pharmacological inhibition of ADAM8. Levels of pAkt and pERK1/2 were increased in GBM cells and correlated with ADAM8 expression, cell survival, and invasiveness. Soluble hepatocyte growth factor (HGF) R/c-met and CD44 were identified as metalloprotease substrates in TMZ-treated GBM cells. Blocking of HGF R/c-met prevented TMZ-induced invasiveness. CONCLUSIONS: ADAM8 causes TMZ resistance in GBM cells by enhancing pAkt/PI3K, pERK1/2, and cleavage of CD44 and HGF R/c-met. Specific ADAM8 inhibition can optimize TMZ chemotherapy of GBM in order to prevent formation of recurrent GBM in patients.

Time course of the effect of a bolus dose of intrathecal baclofen on severe cerebral spasticity.

Continuous intrathecal administration of baclofen with implanted programmable pump systems is recommended in the treatment of severe spasticity of cerebral origin. Prior to pump implantation, a baclofen bolus test (BBT) is used to assess the effectiveness of intrathecal baclofen using clinical scales such as the Modified Ashworth Scale (MAS). In the literature, the time and period of maximum effect of a bolus dose of intrathecally administered baclofen in patients with cerebral spasticity is variously reported. The aim of the study was, therefore, to reveal the time course of the effect of a BBT on severe cerebral spasticity by the use of a recently described spasticity measurement method. Spasticity in knee joints of 13 patients with severe cerebral spasticity was repeatedly assessed using the MAS and also continuously recorded by the measurement of force under circular fibreglass casts. Force was recorded as nettorque by multiplying the force by the distance between sensor and joint axis, thus allowing inter-individual comparison. Half-hour time integrals (TI) of net-torque were determined 9 hours before and 22 hours after intrathecal baclofen administration. Post-BBT half-hour time integrals (TI(+0), TI(+0.5), to TI(+22)) were compared with the mean of 17 pre-BBT half-hour time integrals. Significantly lower post-BBT half-hour time integrals compared with were found between TI(+2) and TI(+8) (Dunnett adjusted p < 0.05). The median lowest TI after BBT of the 13 patients was TI(+4). The lowest mean MAS scores were found 4 hours after BBT. The findings suggest that the greatest effect of BBT on cerebral spasticity occurs between 2 and 8.5 hours, with a maximal effect at 4 hours after intrathecal baclofen injection. Clinical scales used to determine the effect of BBT should thus be carried out during this period-ideally at 4 hours after baclofen injection.