Genetic variants related to angiogenesis and apoptosis in patients with glioma / Variantes genéticas relacionadas à angiogênese e apoptose em pacientes com glioma

ABSTRACT Background Glioma, the most common primary malignant brain tumor in adults, is highly aggressive and associated with a poor prognosis. The objectives of this study were to evaluate the association of genetic polymorphisms related to angiogenesis and apoptosis with gliomas, as well as comorbidities, lifestyle, clinical profile, survival and response to treatment (temozolomide [TMZ] and radiotherapy [RT]) in patients with the disease. Methods In a total of 303 individuals, genotypes were performed by real-time PCR, and clinical data, lifestyle and comorbidities were obtained from medical records and questionnaires. The significance level was set at 5%. Results Smoking, alcohol consumption, systemic arterial hypertension, diabetes mellitus and body mass index prevailed among patients, compared to controls (p < 0.05). The heterozygous genotype rs1468727 (T/C) and the homozygous genotype rs2010963 (G/G) (p > 0.05) were observed in both groups. Lifestyle and comorbidities showed independent risk factors for the disease (p < 0.0001, p = 0.0069, p = 0.0394, respectively). Patients with low-grade gliomas had a survival rate of 80.0 ± 1.7% in three years. For the combination of TMZ+RT, survival was 78.7 ± 7.6% in 20 months, compared to TMZ only (21.9 ± 5.1%, p = 0.8711). Conclusions Genetic variants were not associated with gliomas. Specific lifestyle habits and comorbidities stood out as independent risk factors for the disease. Low-grade gliomas showed an increase in patient survival with TMZ+RT treatment.

RESUMO Introdução Glioma, tumor cerebral maligno, é altamente agressivo e associado a mau prognóstico. Os objetivos deste estudo foram avaliar a associação de polimorfismos genéticos relacionados a angiogênese e apoptose em pacientes com glioma, bem como suas comorbidades, hábitos de vida, perfil clínico, sobrevida e resposta ao tratamento (temozolomida [TMZ] e radioterapia [RT]). Métodos 303 indivíduos foram genotipados por PCR em tempo real, e foram coletados dados clínicos, hábitos de vida e comorbidades. Admitiu-se nível de significância para valor p < 0,05. Resultados Tabagismo, elitismo, hipertensão arterial sistêmica, diabetes mellitus e índice de massa corporal prevaleceram entre os pacientes, comprados aos controles (p < 0,05). O genótipo heterozigoto rs1468727 (T/C) e homozigoto rs2010963 (G/G) (p > 0,05) foram observados em ambos os grupos. Tabagismo, elitismo, hipertensão arterial sistêmica, diabetes mellitus e índice de massa corporal apresentaram fatores de risco independentes para a doença (p < 0.0001, p = 0.0069, p = 0.0394, respectivamente). Os pacientes com gliomas de baixo grau apresentaram sobrevida de 80,0 ± 1,7% em três anos. Para a combinação de RT e TMZ, a sobrevida foi de 78,7±7,6% em 20 meses, em comparação com TMZ (21,9 ± 5,1%, p = 0,8711). Conclusões As variantes genéticas não estiveram associadas aos gliomas. Hábitos de vida e comorbidades específicas destacaram-se como fatores de risco independentes para a doença. O tratamento com TMZ + RT mostrou aumento na sobrevida dos pacientes.

retrospective comparative study of concomitant chemoradiotherapy followed by adjuvant temozolomide versus radiotherapy alone in newly diagnosed Glioblastoma multiforme - an experience at Radium institute, Patna medical college and hospital, India

Introduction: Glioblastoma Multiforme [WHO grade IV glioma] still remains a dreadful diagnosis in oncology with the median survival ranging between 12 to 17 months, despite the recent advances in its management[11,12] It is the most common malignant primary tumour in adults[13]. The standard of care is Maximal Safe Resection followed by Concomitant ChemoRadiotherapy

Methods: During the period 2006 to 2010 at Radium Institute, Patna Medical College and Hospital [PMCH] in India, a study was conducted on 37 newly diagnosed GBM cases in which the control-arm [c-arm] received Conventional Radiotherapy [60Gy/30 number] only whereas the study arm [s-arm] received Concomitant Chemoradiotherapy followed by Adjuvant Temozolomide

Results: The median survival was 15.4 months in the s-arm as compared to 12.4 months in the c-arm. The OS showed a significant improvement with p-value of 0.05 and PFS also showed a benefit with a p-value of 0.005

Conclusion: The results were encouraging with improvement in OS as well as PFS in the s-arm and were at par with the other similar studies conducted in different parts of the world

DNMT1 mediates chemosensitivity by reducing methylation of miRNA-20a promoter in glioma cells

Although methyltransferase has been recognized as a major element that governs the epigenetic regulation of the genome during temozolomide (TMZ) chemotherapy in glioblastoma multiforme (GBM) patients, its regulatory effect on glioblastoma chemoresistance has not been well defined. This study investigated whether DNA methyltransferase (DNMT) expression was associated with TMZ sensitivity in glioma cells and elucidated the underlying mechanism. DNMT expression was analyzed by western blotting. miR-20a promoter methylation was evaluated by methylation-specific PCR. Cell viability and apoptosis were assessed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and TdT-mediated dUTP-biotin nick end labeling assays, respectively. The results showed that compared with parental U251 cells, DNMT1 expression was downregulated, miR-20a promoter methylation was attenuated and miR-20a levels were elevated in TMZ-resistant U251 cells. Methyltransferase inhibition by 5-aza-2\'-deoxycytidine treatment reduced TMZ sensitivity in U251 cells. In U251/TM cells, DNMT1 expression was negatively correlated with miR-20a expression and positively correlated with TMZ sensitivity and leucine-rich repeats and immunoglobulin-like domains 1 expression; these effects were reversed by changes in miR-20a expression. DNMT1 overexpression induced an increase in U251/TM cell apoptosis that was inhibited by the miR-20a mimic, whereas DNMT1 silencing attenuated U251/TM cell apoptosis in a manner that was abrogated by miR-20a inhibitor treatment. Tumor growth of the U251/TM xenograft was inhibited by pcDNA-DNMT1 pretreatment and boosted by DNMT1-small hairpin RNA pretreatment. In summary, DNMT1 mediated chemosensitivity by reducing methylation of the microRNA-20a promoter in glioma cells.

Prediction of Response to Concurrent Chemoradiotherapy with Temozolomide in Glioblastoma: Application of Immediate Post-Operative Dynamic Susceptibility Contrast and Diffusion-Weighted MR Imaging

OBJECTIVE: To determine whether histogram values of the normalized apparent diffusion coefficient (nADC) and normalized cerebral blood volume (nCBV) maps obtained in contrast-enhancing lesions detected on immediate post-operative MR imaging can be used to predict the patient response to concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ). MATERIALS AND METHODS: Twenty-four patients with GBM who had shown measurable contrast enhancement on immediate post-operative MR imaging and had subsequently undergone CCRT with TMZ were retrospectively analyzed. The corresponding histogram parameters of nCBV and nADC maps for measurable contrast-enhancing lesions were calculated. Patient groups with progression (n = 11) and non-progression (n = 13) at one year after the operation were identified, and the histogram parameters were compared between the two groups. Receiver operating characteristic (ROC) analysis was used to determine the best cutoff value for predicting progression. Progression-free survival (PFS) was determined with the Kaplan-Meier method and the log-rank test. RESULTS: The 99th percentile of the cumulative nCBV histogram (nCBV C99) on immediate post-operative MR imaging was a significant predictor of one-year progression (p = 0.033). ROC analysis showed that the best cutoff value for predicting progression after CCRT was 5.537 (sensitivity and specificity were 72.7% and 76.9%, respectively). The patients with an nCBV C99 of < 5.537 had a significantly longer PFS than those with an nCBV C99 of ≥ 5.537 (p = 0.026). CONCLUSION: The nCBV C99 from the cumulative histogram analysis of the nCBV from immediate post-operative MR imaging may be feasible for predicting glioblastoma response to CCRT with TMZ.

Combination hyperbaric oxygen and temozolomide therapy in c6 rat glioma model / Terapia combinada de oxigênio hiperbárico e temozomida no modelo C6 de glioma em ratos

PURPOSE: Temozolomide (TMZ) has anti-tumor activity in patients with malignant glioma. Hyperbaric oxygen (HBO) may enhance the efficacy of certain therapies that are limited because of the hypoxic tumor microenvironment. We examined the combined effects of TMZ-HBO in a rat glioma model. METHODS: After stereotactic injection of C6/LacZ rat glioma cells into the Wistar rats brain, the rats were randomly assigned to three treatment groups [group 1, control treatment; group 2, TMZ alone; group 3, a combination of TMZ and HBO]. Rats were sacrificed 18 days after treatment, and number of intra-/peri-tumoral vessels, microendothelial proliferations, immunohistochemistry and necrotic area were evaluated. RESULTS: Tumoral tissue was stained only sparsely with GFAP. Temozolomide treatment was significantly decreased in tumor tissue intratumoral vessel number / total tumor area level. The level of Ki67 was significantly decreased in the tumor tissue of the group 3. Additionally, the total necrotic area / total tumor volume (%) was decreased significantly in tumor tissue of the group 3 rats compared to group1 and 2. CONCLUSION: The combination of hyperbaric oxygen with temozolomide produced an important reduction in glioma growth and effective approach to the treatment of glioblastoma.

OBJETIVO: A temozolomida (TMZ) tem atividade anti-tumoral em pacientes com glioma maligno. Oxigênio hiperbárico (HBO) pode aumentar a eficácia de terapias que são limitadas devido a um microambiente do tumor hipóxico. Foram examinados os efeitos combinados de TMZ-HBO em um modelo de glioma em rato. MÉTODOS: Após a injeção estereotáxica de células de glioma de rato C6/LacZ no cérebro de ratos Wistar, os ratos foram distribuídos aleatoriamente em três grupos de tratamento: Grupo 1: tratamento de controle. Grupo 2: TMZ sozinho. Grupo 3: uma combinação de TMZ e HBO. Os ratos foram sacrificados 18 dias após o tratamento. Foram avaliados o número de vasos intra-/peri-tumoral, proliferação microendotelial, imunohistoquímica e área necrótica . RESULTADOS: O tecido tumoral foi marcado apenas esparsamente com GFAP. O tratamento com temozolomida diminuiu significativamente o tecido intratumoral e a área total do tumor. O nível de Ki67 foi significativamente diminuído no tecido do tumor do grupo 3. Além disso, a superfície necrótica total / volume total do tumor (%) diminuiu significativamente no tecido do tumor do grupo 3 em comparação com grupo 1 e 2. CONCLUSÃO: A combinação de oxigênio hiperbárico com temozolomida produziu uma redução importante no crescimento do glioma podendo ser abordagem eficaz para o tratamento do glioblastoma.

Temozolomide in aggressive pituitary adenomas and carcinomas

Temozolomide is an alkylating agent used in the treatment of gliomas and, more recently, aggressive pituitary adenomas and carcinomas. Temozolomide methylates DNA and, thereby, has antitumor effects. O6-methylguanine-DNA methyltransferase, a DNA repair enzyme, removes the alkylating adducts that are induced by temozolomide, thereby counteracting its effects. A Medline search for all of the available publications regarding the use of temozolomide for the treatment of pituitary tumors was performed. To date, 46 cases of adenohypophysial tumors that were treated with temozolomide, including 30 adenomas and 16 carcinomas, have been reported. Eighteen of the 30 (60%) adenomas and 11 of the 16 (69%) carcinomas responded favorably to treatment. One patient with multiple endocrine neoplasia type 1 and an aggressive prolactin-producing adenoma was also treated and demonstrated a good response. No significant complications have been attributed to temozolomide therapy. Thus, temozolomide is an effective treatment for the majority of aggressive adenomas and carcinomas. Evidence indicates that there is an inverse correlation between levels of O6-methylguanine-DNA methyltransferase immunoexpression and therapeutic response. Alternatively, high-level O6-methylguanine-DNA methyltransferase immunoexpression correlates with an unfavorable response. Here, we review the use of temozolomide for treating pituitary neoplasms.

Prognostic significance of concomitant radiotherapy in newly diagnosed glioblastoma multiforme: a multivariate analysis of 116 patients

Currently, radiotherapy with concomitant and adjuvant temozolomide has become the standard treatment for glioblastoma. The purpose of this study was to report our experience with radiation plus concomitant temozolomide in 116 patients with glioblastoma multiforme [GBM] and examine the value of different prognostic factors. Retrospective analysis of 116 patients with newly diagnosed GBM, who were treated at our department between January 1994 and March 2009. Age, gender, Karnofsky performance scale [KPS] score, a preoperative history of seizures, extent of surgery, total radiotherapy dose, and use of concomitant and adjuvant temozolomide were evaluated in uni- and multivariate analyses. Survival was determined using the Kaplan-Meier method, and differences were compared using the log rank test. Cox regression analysis was conducted to identify the independent prognostic factors. The median overall survival time was 9 months, and the 1- and 2-year survival rates were 41.9% and 9.6%, respectively. The univariate analysis revealed that age, KPS score, presence of seizures, radiation doses, and use of concomitant and adjuvant temozolomide were significant prognostic factors. The multivariate analysis confirmed that the age, KPS score, presence of seizures, radiation doses, and use of concomitant and adjuvant temozolomide were independent, significant prognostic factors. The results of our analyses demonstrate that radiation with concomitant and adjuvant temozolomide yields encouraging outcomes in patients with GBM, validating the results published in research papers. In addition, age, KPS score, presence of seizures, and radiation doses were identified as prognostic factors

overview of therapeutic approaches to brain tumor stem cells

Primary and secondary malignant central nervous system [CNS] tumors are devastating invasive tumors able to give rise to many kinds of differentiated tumor cells. Glioblastoma multiform [GBM], is the most malignant brain tumor, in which its growth and persistence depend on cancer stem cells with enhanced DNA damage repair program that also induces recurrence and resists current chemo- and radiotherapies. Unlike non-tumor stem cells, tumor stem cells lack the normal mechanisms that regulate proliferation and differentiation, resulting in uncontrolled production and incomplete differentiation of tumor cells. In current paper recent developments and new researches in the field of brain tumor stem cells have been reviewed

Combination Therapy with Rituximab and Temozolomide for Recurrent and Refractory Primary Central Nervous System Lymphoma

High-dose methotrexate-based chemotherapy has extended survival in patients with primary central nervous system lymphoma (PCNSL). However, although salvage treatment is necessary in recurrent and refractory PCNSL, this has not been standardized. We herein describe the efficacy of a combination of rituximab and temozolomide (TMZ) in two consecutive patients with recurrent and refractory PCNSL. Based on the immunohistochemical study, case 1 had a non-germinal center B-cell-like (non-GCB) subtype, was positive for bcl-2 and negative for O6-methylguanine-DNA methyltransferase (MGMT). Case 2 was GCB subtype, bcl-2-, and MGMT+. Because of the positive expression of MGMT, interferon-beta was additionally given in case 2. Complete responses and partial responses were obtained after the third and fourth cycles of combination therapy, respectively. This was maintained for 12 months, with acceptable toxicity. The combination of rituximab and TMZ was effective in tumors with different immunohistochemical profiles. This combination therapy warrants further study in a larger population.

Glioblastoma multiforme of the cerebellum

Glioblastoma multiforme [GBM] is a highly malignant glial tumor seen commonly in the cerebral hemispheres, but rarely encountered in the cerebellum. It may occur at any age, but is seen more often in adult age groups. Despite its rarity, GBM should be considered in patients with a ring-enhancing lesion in the cerebellum. No consensus regarding the best management has yet been established. However, multimodal treatment is currently available to deal with these lesions: wide excision with radiochemotherapy may improve and prolong the patient's life. Although the outcome remains dismal, we emphasize that timely multi modal treatment may provide the patient a better outcome and longer life. Herein, we report 2 new cases of cerebellar GBM and discuss their outcome and present a review of the relevant literature

Optimizing radiotherapy of brain tumours by a combination of temozolomide & lonidamine.

BACKGROUND & OBJECTIVE: Temozolomide (TMZ), a second generation alkylating drug, an effective cytotoxic agent as well as radiosensitizer for malignant brain tumours, has side effects like myelosuppression. Lonidamine (LND) increases the effectiveness of several experimental multiple chemotherapy protocols, without increasing bone marrow toxicities and is effective in brain tumour patients. The objective of the present studies was to investigate whether combining clinically relevant doses of LND and TMZ could increase the proliferation and radiation response of malignant human brain tumour cells in vitro. METHODS: A malignant human glioma (U373MG) cell line was used in these studies. TMZ (20, 40 or 60 microM) or LND (100, 150 or 200 microM), or the combination of both (20 and 100 microM, respectively) in 0.1 per cent dimethyl sulphoxide (DMSO) were added three days after setting up cultures, in six well plates (5 x 10(4) cells/ well). The effects of continuous treatment for two days on proliferation response and cytotoxicity were studied after trypsinization; by cell counts and the uptake of trypan blue dye (0.5%). For the study of radiation (60Co-Gamma-rays, 2 Gy) response, drugs were removed 4 h after irradiation and cultures were grown further in drug free, normal growth medium for another 20 h or 44 h. RESULTS: Continuous presence of TMZ or LND for two days significantly inhibited cell proliferation in a concentration dependent manner. The frequencies of non viable cells increased significantly only at higher concentrations of LND. Combination of 20 microM TMZ with 100 microM LND had additive effects on proliferation response, without affecting cell viability. Short-term drug treatments without irradiation did not induce micronuclei formation. Cell proliferation and viability were also not affected. However, post-irradiation presence of either of these drugs for 4 h significantly reduced the proliferation response, 24 and 48 h after treatments. It was further inhibited by the combination treatment. On the contrary, radiation induced micronuclei formation was enhanced by either of the drugs; which was significantly increased by the combined treatment, 24 h as well as 48 h after irradiation. No effects on cell viability were observed, immediately after these treatments as well as at later time points. INTERPRETATION & CONCLUSION: Our findings showed that combination of TMZ and LND at clinically achievable, low plasma concentrations could inhibit tumour growth, and lonidamine could reduce the dose of temozolomide required for radiosensitization of brain tumours.

A multivariate analysis of patients with glioma: a treatment outcome and prognostic factor for survival.

OBJECTIVE: To evaluate the treatment outcome and to examine the influence of factors on survival of patients with glioma. MATERIAL AND METHOD: One hundred and eighty-nine patients were included. Data on the patient's age, sex, KPS score, tumor location and survival time were collected and analyzed. RESULTS: Tumor grade and age had effect on survival of the patients. The median survival time (MST) of patients with grade II-IV glioma was 80.0, 20.0 and 9 months, respectively. Only the tumor site had influence on survival of patients with grade II glioma. In patients with grade III glioma, only KPS score had an impact on survival. In patients with grade IV glioma, none of the factors had an effect on survival. CONCLUSION: The treatment outcome of the patients in Chulalongkorn University is comparable to other series. Multivariate analysis identified factors that had influence on survival of the patients.