Fractionated irradiation combined with carbogen breathing and nicotinamide of two human glioblastomas grafted in nude mice

Nicotinamide N-Methyltransferase in Head and Neck Tumors: A Comprehensive Review

The head and neck tumors (HNT) are a heterogeneous group of diseases ranging from benign to malignant lesions, with distinctive molecular and clinical behaviors. Several studies have highlighted the presence of an altered metabolic phenotype in HNT, such as the upregulation of nicotinamide N-methyltransferase (NNMT). However, its biological effects have not been completely disclosed and the role of NNMT in cancer cell metabolism remains unclear. Therefore, this comprehensive review aims to evaluate the available literature regarding the biological, diagnostic, and prognostic role of NNMT in HNT. NNMT was shown to be significantly overexpressed in all of the evaluated HNT types. Moreover, its upregulation has been correlated with cancer cell migration and adverse clinical outcomes, such as high-pathological stage, lymph node metastasis, and locoregional recurrences. However, in oral squamous cell carcinoma (OSCC) these associations are still debated, and several studies have failed to demonstrate the prognostic significance of NNMT. The shRNA-mediated gene silencing efficiently suppressed the NNMT gene expression and exhibited a clear inhibitory effect on cell proliferation, promoting the expression of apoptosis-related proteins and modulating the cell cycle. NNMT could represent a new molecular biomarker and a new target of molecular-based therapy, although further studies on larger patient cohorts are needed to explore its biological role in HNT.

Genetic alterations following ionizing radiation in human ovarian cancer-derived endothelial cells

Recent studies have focused on the role of endothelial cells during tumor radiotherapy, and the majority of studies have found that the rate of endothelial cell apoptosis determines the response of the tumor to ionizing radiation treatment. However, gene expression changes in human ovarian cancer-derived endothelial cells in response to X-ray radiation remains poorly understood. The present study was conducted to investigate the radiation-induced gene alterations in human ovarian cancer-derived endothelial cells and to provide novel potential targets for combined anti-angiogenesis and radiation therapy for the treatment of human ovarian cancer. Ovarian cancer-derived endothelial cells, which were harvested from six human ovarian epithelial carcinomas prior to and 4 h after 400 cGy X-ray irradiation, were analyzed using cDNA microarray technology. Significant genes were selected to corroborate the microarray experiments using a quantitative polymerase chain reaction (qPCR). A total of 28 genes common to all the cDNA microarray results were identified, of which 22 genes were found to be consistently upregulated or downregulated. Thirteen genes were upregulated persistently and nine genes downregulated persistently following irradiation with 400 cGy X-ray in comparison with the matched group. The majority of the significantly altered genes (≥2-fold change in expression) were found to have a role in vasculogenesis, cell cycle regulation, inflammation and the immune response, cell growth and apoptosis, nicotinamide metabolism, cell signaling, chemokines and cell adhesion. Eight randomly selected genes were corroborated using qPCR technology. Radiation-induced gene alterations in ovarian cancer-derived endothelial cells and gene-related pathways were associated with vasculogenesis and the radiosensitivity of human ovarian cancer, and may provide promising biomarkers for radiation and anti-angiogenesis treatments against ovarian carcinoma.

Nicotinamide N-methyltransferase overexpression is associated with Akt phosphorylation and indicates worse prognosis in patients with nasopharyngeal carcinoma

Nicotinamide N-methyltransferase (NNMT) is overexpressed in many human cancers and is associated with poor prognosis. Akt (also known as protein kinase B) is an evolutionarily conserved serine/threonine kinase, serving as a downstream effector of the phosphatidylinositol 3-kinase signaling pathway. NNMT was first identified as a differentially upregulated gene in nasopharyngeal cancer tissues through data mining from published transcriptomic databases. Since no prior study has attempted to evaluate the clinical significance of NNMT or phosphorylated Akt (pAkt) expression in nasopharyngeal cancer, this study explores their expression in a large cohort of patients with nasopharyngeal cancer. The study included 124 nasopharyngeal cancer patients who were free of distant metastasis at initial diagnosis. Pathological slides were reviewed and clinical findings collected. We evaluated the expression of NNMT and pAkt immunohistochemically, stratified them into two groups (high and low expression) and examined the correlation with disease-specific survival (DSS), metastasis-free survival (MeFS), local recurrence-free survival (LRFS), and various clinicopathological factors. NNMT expression was significantly positively associated with pAkt expression. The high expression of both markers was significantly associated with an increment of tumor stage (p = 0.006 and p = 0.006, respectively). High expression of NNMT correlated significantly with a more aggressive clinical course and a significantly shorter DSS. Furthermore, NNMT expression and pAkt expression were strongly predictive of MeFS (p = 0.008; p = 0.0063) and LRFS (p = 0.005; p = 0.0125). In multivariate analysis, high expression of NNMT remained as a robust prognosticator for both end points evaluated. It independently portended inferior DSS (p = 0.02, HR = 1.976) and worse MeFS (p = 0.029, HR = 2.022) after tumor stage (p = 0.033, HR = 2.150; p = 0.028, HR = 2.942, for DSS and LRFS, respectively). We found NNMT positively correlated with pAkt expression and was independent adverse prognosticators of patient survival. NNMT therefore has potential utility as an indicator for prognosis, predicting treatment response to chemotherapy or radiation therapy, and even as a therapeutic target in the future.

Response of intracerebral human glioblastoma xenografts to multifraction radiation exposures

PURPOSE

We investigated the effects of fractionated radiation treatments on the life spans of athymic rats bearing intracerebral brain tumors.

METHODS AND MATERIALS

U-251 MG or U-87 MG human glioblastoma cells were implanted into the brains of athymic rats, and the resulting tumors were irradiated once daily with various doses of ionizing radiation for 5 consecutive days or for 10 days with a 2-day break after Day 5.

RESULTS

Five daily doses of 1 and 1.5 Gy, and 10 doses of 0.75 and 1 Gy, cured some U-251 MG tumors. However, five daily doses of 0.5 Gy increased the survival time of animals bearing U-251 MG tumors 5 days without curing any animals of their tumors. Ten doses of 0.3 Gy given over 2 weeks extended the lifespan of the host animals 9 days without curing any animals. For U-87 MG tumors, 5 daily doses of 3 Gy produced an increased lifespan of 8 days without curing any animals, and 10 doses of 1 Gy prolonged lifespan 5.5 days without curing any animals. The differences in extension of life span between the 5- and 10-fraction protocols were minor for either tumor type.

CONCLUSION

The finding that the U-251 MG tumors are more sensitive than U-87 MG tumors, despite the fact that U-251 MG tumors contain many more hypoxic cells than U-87 MG tumors, suggests the intrinsic cellular radiosensitivities of these cell lines are more important than hypoxia in determining their in vivo radiosensitivities.

Radiotherapy and Temozolomide for Newly Diagnosed Glioblastoma: Recursive Partitioning Analysis of the EORTC 26981/22981-NCIC CE3 Phase III Randomized Trial

Purpose

The European Organisation for Research and Treatment of Cancer and National Cancer Institute of Canada trial on temozolomide (TMZ) and radiotherapy (RT) in glioblastoma (GBM) has demonstrated that the combination of TMZ and RT conferred a significant and meaningful survival advantage compared with RT alone. We evaluated in this trial whether the recursive partitioning analysis (RPA) retains its overall prognostic value and what the benefit of the combined modality is in each RPA class.

Patients and Methods

Five hundred seventy-three patients with newly diagnosed GBM were randomly assigned to standard postoperative RT or to the same RT with concomitant TMZ followed by adjuvant TMZ. The primary end point was overall survival. The European Organisation for Research and Treatment of Cancer RPA used accounts for age, WHO performance status, extent of surgery, and the Mini-Mental Status Examination.

Results

Overall survival was statistically different among RPA classes III, IV, and V, with median survival times of 17, 15, and 10 months, respectively, and 2-year survival rates of 32%, 19%, and 11%, respectively (P < .0001). Survival with combined TMZ/RT was higher in RPA class III, with 21 months median survival time and a 43% 2-year survival rate, versus 15 months and 20% for RT alone (P = .006). In RPA class IV, the survival advantage remained significant, with median survival times of 16 v 13 months, respectively, and 2-year survival rates of 28% v 11%, respectively (P = .0001). In RPA class V, however, the survival advantage of RT/TMZ was of borderline significance (P = .054).

Conclusion

RPA retains its prognostic significance overall as well as in patients receiving RT with or without TMZ for newly diagnosed GBM, particularly in classes III and IV.

Radiotherapy and chemotherapy with or without carbogen and nicotinamide in inoperable biopsy-proven glioblastoma multiforme

BACKGROUND

Nicotinamide and carbogen have been shown to enhance the radiation effect in tumour models.

PURPOSE

Prospective evaluation of the toxicity and efficacy of carbogen and nicotinamide with external beam radiotherapy in the management of inoperable glioblastoma.

PATIENTS AND METHODS

From April 1995 to December 1997, 33 patients with inoperable biopsy-proven glioblastoma multiforme (GBM) were enrolled in a phase II trial, to undergo radiotherapy (59.4 Gy in 1.8 Gy/fraction), intra-arterial cerebral chemotherapy (ACNU 100 mg/m(2), three cycles), carbogen breathing (15 l/min), and nicotinamide (85 mg/kg). This experimental group was compared to a control group of 38 patients with inoperable GBM treated with radiotherapy and three cycles of nitrosourea-based chemotherapy from January 1990 to March 1995, in our institution.

RESULTS

In the experimental group, carbogen breathing was well tolerated, but only 51.5% of patients completed daily nicotinamide over the 6.5-week treatment period. Nausea and vomiting were the most frequent side effects of nicotinamide. No significant difference in overall survival was observed among the two treatment groups: median survival times were 36.7 and 35.3 weeks for patients treated with carbogen and nicotinamide, and for those treated in the control group, respectively.

CONCLUSION

The association of carbogen and nicotinamide with radiotherapy is feasible, but tolerable only in 51.5% of patients with GBM. Carbogen and nicotinamide did not appear to modify the evolution of glioblastoma.

A potential role of heat shock proteins and nicotinamide N-methyl transferase in predicting response to radiation in bladder cancer

The use of definitive radiotherapy for treatment of invasive bladder cancer has the advantage of preserving bladder function, but tumour regression is only achieved in approximately 40-50% of patients. Knowledge of the molecular basis of sensitivity to ionizing radiation and identification of potential molecular predictors will provide useful information regarding patient response and thus help clinicians to individualize treatment. The recent application of cDNA expression array technology provides a useful tool to investigate hundreds or even thousands of genes in a single experiment. In our study, we have used the Atlas human stress cDNA array trade mark to investigate the expression profile of stress-related and DNA repair genes in a radioresistant bladder carcinoma cell line (MGH-U1) and its radiosensitive subclone (S40b). This provides an ideal situation to study genes related to radiation because the genotypes of both cell lines are basically similar and differential changes detected are likely to be related to the different radiosensitivity phenotype. Of 234 genes blotted on the array, 3 genes (Heat shock protein 90, Heat shock protein 27 and Nicotinamide N-methyl transferase) showed consistent downregulation in the radiosensitive clone in 2 independent experiments. These results were further confirmed for HSP27 and NNMT using Sybr Green I-based real-time QRT-PCR. The role of heat shock proteins (HSPs) in response to radiation remains to be determined; however, the results of our present work suggest a possible role of HSP27 in determining radiosensitivity. Our study also opens avenues for the investigation of genes, such as NNMT, which has not previously been linked to response to radiation.