Pilot evaluation of cytokine levels in patients undergoing radiotherapy for brain tumor

Advances in Radiotherapy for Brain Metastases

Radiotherapy remains a cornerstone treatment of brain metastases. With new treatment advances, patients with brain metastases are living longer, and finding solutions for mitigating treatment-related neurotoxicity and improving quality of life is important. Historically, whole-brain radiation therapy (WBRT) was widely used but treatment options such as hippocampal sparing WBRT and stereotactic radiosurgery (SRS) have emerged as promising alternatives. Herein, we discuss the recent advances in radiotherapy for brain metastases including the sparing of critical structures that may improve long-term neurocognitive outcomes (eg, hippocampus, fornix) that may improve long-term neurocognitive outcome, evidence supporting preoperative and fractionated-SRS, and treatment strategies for managing radiation necrosis.

Unraveling the peripheral and local role of inflammatory cytokines in glioblastoma survival

Glioblastoma (GBM) is a life-threatening disease that presents high morbidity and mortality. The standardized treatment protocol results in a global survival of less than three years in the majority of cases. Immunotherapies have gained wide recognition in cancer treatment; however, GBM has an immunosuppressive microenvironment diminishing the possible effectiveness of this therapy. In this sense, investigating the inflammatory settings and the tumoral nature of GBM patients are an important goal to create an individual plan of treatment to improve overall survival rate and quality of life of these patients. Thirty-two patients who underwent surgical resection of GBM were included in this study. Tumor samples and 10 mL of peripheral blood were collected and immediately frozen. TNF-a, IL-1a and IL-4 were evaluated in the tumor and TNF-a, IL-1a and TGF-b in the plasma by Luminex assay. Immunohistochemistry analysis to determine immune celular profile was done, including immunohistochemistry for CD20, CD68 and CD3. Three cases were excluded. Tumor topography, tumor nature, and tumor volume reconstructions were accurately analyzed by T1-weighted, T2-weighted, and FLAIR magnetic resonance imaging. We found that GBM patients with below median peripheral levels of TNF-a and IL-1a had a decreased survival rate when compared to above median patients. On the other hand, patients with below median peripheral levels of TGF-b increased overall survival rate. Intratumoral IL-1a above median was associated with higher number of macrophages and fewer with B cells. Furthermore, plasmatic TNF-a levels were correlated with intratumoral TNF-a levels, suggesting that peripheral cytokines are related to the tumoral microenvironment. Even though tumor size has no difference regarding survival rate, we found a negative correlation between intratumoral IL-4 and tumor size, where larger tumors have less IL-4 expression. Nevertheless, the tumoral nature had a significant effect in overall survival rate, considering that infiltrative tumors showed decreased survival rate and intratumoral TNF-a. Moreover, expansive tumors revealed fewer macrophages and higher T cells. In multiple variation analyzes, we demonstrated that infiltrative tumors and below median peripheral IL-1a expression represent 3 times and 5 times hazard ratio, respectively, demonstrating a poor prognosis. Here we found that peripheral cytokines had a critical role as prognostic tools in a small cohort of GBM patients.

Carbon ion radiotherapy boost in the treatment of glioblastoma: a randomized phase I/III clinical trial

Background

Glioblastoma (GBM) is a highly virulent tumor of the central nervous system, with a median survival < 15 months. Clearly, an improvement in treatment outcomes is needed. However, the emergence of these malignancies within the delicate brain parenchyma and their infiltrative growth pattern severely limit the use of aggressive local therapies. The particle therapy represents a new promising therapeutic approach to circumvent these prohibitive conditions with improved treatment efficacy.

Methods and design

Patients with newly diagnosed malignant gliomas will have their tumor tissue samples submitted for the analysis of the status of O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation. In Phase I, the patients will undergo an induction carbon ion radiotherapy (CIRT) boost followed by 60 GyE of proton irradiation with concurrent temozolomide (TMZ) at 75 mg/m². To determine the maximal dose of safe induction boost, the tolerance, and acute toxicity rates in a dose-escalation manner from 9 to 18 GyE in three fractions will be used. In Phase III, GBM-only patients will be randomized to receive either 60 GyE (2 GyE per fraction) of proton irradiation with concurrent TMZ (control arm) or a CIRT boost (dose determined in Phase I of this trial) followed by 60 GyE of proton irradiation with concurrent TMZ. The primary endpoints are overall survival (OS) and toxicity rates (acute and long-term). Secondary endpoints are progression-free survival (PFS), and tumor response (based upon assessment with C-methionine/fluoro-ethyl-tyrosine positron emission tomography [MET/FET PET] or magnetic resonance imaging [MRI] and detection of serologic immune markers). We hypothesize that the induction CIRT boost will result in a greater initial tumor-killing ability and prime the tumor microenvironment for enhanced immunologic tumor clearance, resulting in an expected 33% improvement in OS rates.

Discussion

The prognosis of GBM remains grim. The mechanism underpinning the poor prognosis of this malignancy is its chronic state of tumor hypoxia, which promotes both immunosuppression/immunologic evasion and radio-resistance. The unique physical and biological properties of CIRT are expected to overcome these microenvironmental limitations to confer an improved tumor-killing ability and anti-tumor immune response, which could result in an improvement in OS with minimal toxicity.

Trial registration number This trial has been registered with the China Clinical Trials Registry, and was allocated the number ChiCTR-OID-17013702.

Bevacizumab for the Treatment of Gammaknife Radiosurgery-Induced Brain Radiation Necrosis

BACKGROUND

Radiation necrosis is one of the complications of Gammaknife radiosurgery. The traditional treatment of radiation necrosis carries a high risk of failure, Bevacizumab is an antiangiogenic monoclonal antibody against vascular endothelial growth factor, a known mediator of cerebral edema. It can be used to successfully treat brain radiation necrosis.

PATIENT DESCRIPTION

Two patients with a history of small cell lung cancer presented with metastatic disease to the brain. They underwent Gammaknife radiosurgery to brain metastases. Several months later, magnetic resonance imaging showed radiation necrosis with significant surrounding edema. The patients had a poor response to treatment with dexamethasone. They were eventually treated with bevacizumab (5 mg/kg every 2 weeks, 7.5 mg/kg every 3 weeks, respectively), and the treatment resulted in significant clinical and radiographic improvement.

CONCLUSION

Bevacizumab can be successfully used to treat radiation necrosis induced by Gammaknife radiosurgery in patients with cerebral metastases. It is of particular benefit in patients with poor reaction to corticosteroids and other medications.

Modulation of MMP-2 and MMP-9 secretion by cytokines, inducers and inhibitors in human glioblastoma T-98G cells

Brain tumors are highly aggressive, characterized by the secretion of high levels of matrix metalloproteinase (MMP)-2 and MMP-9 that degrade the extracellular matrix and basement membrane, allowing cancer cells to spread to distal organs. Various cytokines, mitogens, growth factors, inducers and inhibitors control MMP activity. We investigated the roles of these in the regulation of MMP-2 and MMP-9 in human glioblastoma T-98G cells. Human T-98G cells were grown in DME supplemented with 15% fetal bovine serum and antibiotics in 24-well tissue culture plates. At near confluence, cells were washed with phosphate-buffered saline and incubated in serum-free media with: phorbol 12-myristate 13-acetate (PMA) at 10, 25, 50 and 100 ng/ml; tumor necrosis factor (TNF)-α and interleukin (IL)-1β at 0.1, 1, 10 and 25 ng/ml; lipopolysaccharide (LPS) at 10, 25, 50 and 100 µg/ml; epigallocatechin gallate (EGCG) and doxycycline (Dox) at 10, 25, 50 and 100 µM without and with PMA; a nutrient mixture (NM) containing lysine, proline, ascorbic acid and green tea extract without and with PMA at 10, 50, 100, 500 and 1,000 µg/ml; actinomycin D and cyclohexamide at 2 and 4 µM; retinoic acid and dexamethasone at 50 µM. After 24 h the media were removed and analyzed for MMP-2 and MMP-9 by zymography and densitometry. Glioblastoma T-98G cells expressed only one band corresponding to MMP-2. PMA treatment showed increased MMP-2 and MMP-9 secretions up to 25 ng/ml and decreased levels of secretions at 50 and 100 ng/ml, with no significant overall effect. TNF-α induced an up and down effect on MMP-2 and a slight induction of MMP-9. IL-1β demonstrated a slight dose-dependent increase in T-98G secretion of MMP-2, but no induction of MMP-9. LPS showed dose-dependent decreased inactive MMP-2 secretion, increased active MMP-2 secretion and no effect on MMP-9. EGCG, Dox and NM, without and with PMA, downregulated the expression of MMP-2 and MMP-9 in a dose-dependent manner. Actinomycin D, cyclohexamide, retinoic acid and dexamethasone also had inhibitory effects on MMP-2. Our results showed that cytokines, mitogens and inhibitors modulated T-98G cell MMP-2 and MMP-9 expression, suggesting the clinical use of MMP inhibitors, particularly such potent and non-toxic ones as the nutrient mixture and its component EGCG in the management of glioblastoma cancers.

Immunological markers that predict radiation toxicity

Radiotherapy is a major modality of cancer treatment responsible for a large proportion of cancer that is cured. Radiation exposure induces an inflammatory response which can be influenced by genetic, epigenetic, tumour, health and other factors which can lead to very different treatment outcomes between individuals. Molecules involved in the immunological response provide excellent potential biomarkers for the prediction of radiation-induced toxicity. The known molecular and cellular immunological responses in relation to radiation and the potential to improve cancer treatment are presented in this review. In particular, immunological biomarkers of radiation-induced fibrosis and pneumonitis in cancer radiotherapy patients are discussed.

Elevated serum IL-17A but not IL-6 in glioma versus meningioma and schwannoma

BACKGROUND

There is a Th1/Th2 cytokine imbalance and expression of IL-17 in patients with brain tumours. We aimed to compare the levels of IL-17A and IL-6 in sera of glioma, meningioma and schwannoma patients as well as in healthy individuals.

MATERIALS AND METHODS

IL-17A and IL-6 levels were measured in sera of 38 glioma, 24 meningioma and 18 schwannoma patients for comparison with 26 healthy controls by commercial ELISA assays.

RESULTS

We observed an increase in the IL-17A in 30% of glioma patients while only 4% and 5.5% of meningioma and schwannoma patients and none of the healthy controls showed elevated IL-17A in their sera (0.29 ± 0.54, 0.03 ± 0.15 and 0.16 ± 0.68 vs. 0.00 ± 0.00 pg/ml; p=0.01, p=0.01 and p=0.001, respectively). There was also a significant decrease in the level of IL-6 in glioma patients compared to healthy controls (2.34 ± 4.35 vs. 4.67 ± 4.32 pg/ml; p=0.01). There was a direct correlation between the level of IL-17A and age in glioma patients (p=0.005). Glioma patients over 30 years of age had higher IL-17A and lower IL-6 in their sera compared to the young patients. In addition, a non-significant grade-specific inverse trend between IL-17A and IL-6 was observed in glioma patients, where high-grade gliomas had higher IL-17A and lower IL-6.

CONCLUSIONS

Our data suggest a Th17 mediated inflammatory response in the pathogenesis of glioma. Moreover, tuning of IL-6 and IL-17A inflammatory cytokines occurs during progression of glioma. IL-17A may be a potential biomarker and/or immunotherapeutic target in glioma cases.

HAb18G/CD147 promotes radioresistance in hepatocellular carcinoma cells: a potential role for integrin β1 signaling

Radiotherapy has played a limited role in the treatment of hepatocellular carcinoma (HCC) due to the risk of tumor radioresistance. A previous study in our laboratory confirmed that CD147 interacts with integrin β1 and plays an important role in modulating the malignant properties of HCC cells. In this study, we further evaluated the role of CD147 in the radioresistance of HCC and as a potential target for improving radiosensitivity. Upon irradiation, the colony formation, apoptosis, cell-cycle distribution, migration, and invasion of SMMC-7721, CD147-knockout SMMC-7721, HepG2, and CD147-knockdown HepG2 cells were determined. A nude mouse xenograft model and a metastatic model of HCC were used to detect the role of CD147 in radioresistance in vivo. Deletion of HAb18G/CD147 significantly enhanced the radiosensitivity of SMMC-7721 and HepG2 cells, and knocking out HAb18G/CD147 in SMMC-7721 cells attenuated irradiation-enhanced migration and invasion. The knockout and antibody blockade of CD147 decreased the tumor growth and metastatic potentials of HCC cells under irradiation. CD147-deleted SMMC-7721 cells showed diminished levels of calpain, cleaved talin, active integrin β1, and decreased p-FAK (Tyr397) and p-Akt (Ser473) levels. FAK and PI3K inhibitors, as well as integrin β1 antibodies, increased the radiation-induced apoptosis of SMMC-7721 cells. Our data provide evidence for CD147 as an important determinant of radioresistance via the regulation of integrin β1 signaling. Inhibition of the HAb18G/CD147 integrin interaction may improve the efficiency of radiosensitivity and provide a potential new approach for HCC therapy.

Pathophysiological mechanisms regulated by cytokines in gliomas

Glioma, a neuroglia originated malignancy, consists of one of the most aggressive primary tumors of the central nervous system with poor prognosis and lack of efficient treatment strategy. Cytokines have been implicated in several stages of glioma progression, participating in tumor onset, growth enhancement, angiogenesis and aggressiveness. Interestingly, cytokines have also the ability to inhibit glioma growth upon specific regulation or interplay with other molecules. This review addresses the dual role of major cytokines implicated in glioma pathology, pointing toward promising therapeutic approaches.

Inflammatory cytokines, interleukin-1 beta and tumor necrosis factor-alpha, upregulated in glioblastoma multiforme, raise the levels of CRYAB in exosomes secreted by U373 glioma cells

In the brain, levels of inflammatory cytokines, interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α), are elevated under traumatic brain injury, neuroinflammatory conditions and glioblastoma multiforme (GBM). In GBM, the levels of small heat shock protein, CRYAB (HspB5) are also reported to be elevated, where it has been shown to exert anti-apoptotic activity. Interestingly, CRYAB is secreted via exosomes by various cells. In order to understand the relation between inflammatory cytokines and CRYAB, U373 glioma cells, were stimulated with proinflammatory cytokines, IL-1β and TNF-α, and their effect on CRYAB levels in cells and secreted exosomes was studied. Our results show that U373 cells produce and secrete CRYAB via exosomes and that stimulation with IL-1β and TNF-α significantly increase the levels of CRYAB in not only the cells but also in the secreted exosomes. In addition, cytokine stimulation of U373 cells brings about changes in the secreted exosomal proteome, many of which are involved in cancer progression.

Cytokines: shifting the balance between glioma cells and tumor microenvironment after irradiation

Malignant gliomas invariably recur after irradiation, showing radioresistance. Meanwhile, cranial irradiation can bring some risk for developing cognitive dysfunction. There is increasing evidence that cytokines play their peculiar roles in these processes. On the one hand, cytokines directly influence the progression of malignant glioma, promoting or suppressing tumor progression. On the other hand, cytokines indirectly contribute to the immunologic response against gliomas, exhibiting pro-inflammatory or immunosuppressive activities. We propose that cytokines are not simply unregulated products from tumor cells or immune cells, but mediators finely adjust the balance between glioma cells and tumor microenvironment after irradiation. The paper, therefore, focuses on the changes of cytokines after irradiation, analyzing how these mediate the response of tumor cells and normal cells to irradiation. In addition, cytokine-based immunotherapeutic strategies, accompanied with irradiation, for the treatment of gliomas are also discussed.

Linking the history of radiation biology to the hallmarks of cancer

Hanahan and Weinberg recently updated their conceptual framework of the "Hallmarks of Cancer". The original article, published in 2000, is among the most highly cited reviews in the field of oncology. The goal of this review is to highlight important discoveries in radiation biology that pertain to the Hallmarks. We identified early studies that exemplified how ionizing radiation affects the hallmarks or how radiation was used experimentally to advance the understanding of key hallmarks. A literature search was performed to obtain relevant primary research, and topics were assigned to a particular hallmark to allow an organized, chronological account of the radiobiological advancements. The hallmarks are reviewed in an order that flows from cellular to microenvironmental effects.

Bevacizumab for critical brain metastases in a patient with pulmonary pleomorphic carcinoma

Bevacizumab was initially contraindicated in patients with brain metastases, but several reports have shown the efficacy and safety of bevacizumab for brain metastases. We herein report the case of a patient with pulmonary pleomorphic carcinoma for which bevacizumab plus weekly paclitaxel following whole-brain radiotherapy (WBRT) was effectively and safely administered for critical and refractory brain metastases. Although the 50-year-old male patient received WBRT with anti-edema therapies for progressive brain metastases, his clinical symptoms deteriorated rapidly. After the completion of WBRT, we administered bevacizumab plus weekly paclitaxel, and his neurological symptoms improved dramatically. Brain magnetic resonance imaging demonstrated a marked response by the brain metastases and improved brain edema. This case suggested both synergism between WBRT and bevacizumab, and an anti-edema effect of bevacizumab. Bevacizumab may be therefore a potent therapeutic option for patients with refractory brain metastases.

Radiation enhances the invasiveness of irradiated and nonirradiated bystander hepatoma cells through a VEGF-MMP2 pathway initiated by p53

Recent evidence has shown that irradiation can promote the invasiveness of hepatocellular carcinoma cells and have an impact on the invasive behavior of nonirradiated surrounding cancer cells, which may enhance overall tumor aggressiveness. However, the role of the TP53 tumor suppressor gene in the invasion of irradiated hepatoma cells and their nonirradiated bystanders remain largely unknown. In the present study, we found that irradiation increased the invasiveness of human hepatoma HepG2 cells, and pretreatment of the cells with SU1498 (an inhibitor of vascular endothelial growth factor receptor 2, VEGFR2) and GM6001 (an inhibitor of matrix metalloproteinases 2, MMP2) demonstrated that radiation-enhanced invasiveness is associated with the interplay between MMP2 and VEGF signaling. In addition, while radiation-induced expression and phosphorylation of p53, inhibition of p53 function with pifithrin-α or transfection of cells with p53 siRNA significantly reduced the activation of both MMP2 and VEGF and resulted in a reduction of radiation-induced invasiveness. Interestingly, we also found that the invasiveness of the nonirradiated bystander cells was also elevated after co-culturing with irradiated cells and that bystander invasive potential was regulated paracrine in a manner by MMP2 and VEGF from the irradiated cells through a p53-dependent mechanism. Taken together, our data demonstrate that radiation-induced up-regulation of p53 is responsible for the promotion of VEGF-MMP2 pathway involved in the enhancement of invasiveness of both irradiated and bystander hepatoma cells.

Prognostic importance of markers for inflammation, angiogenesis and apoptosis in high grade glial tumors during temozolomide and radiotherapy

INTRODUCTION

Angiogenesis, inflammation and apoptosis have an important place in the carcinogenesis of high-grade gliomas (HGG). We evaluated the postoperative levels and the prognostic importance of tumor necrosis factor-alpha (TNFα), interleukin 6 (IL6), endoglin (CD105), vascular endothelial growth factor (VEGF), M65 and M30 as markers of inflammation, angiogenesis and apoptosis in patients with HGG.

METHODS AND RESULTS

Postoperative pretreatment sera were collected from 44 newly diagnosed patients with HGG. The control group was also consisted of 44 healthy people. The median age of all patients with HGG was 59 (range: 30-80). Temozolomide concurrent with radiotherapy was given to 37 patients. Thereafter 24 patients received consolidation temozolomide monotherapy. Mean chemotherapy cycle was 4.2. Progression free survival and overall survival were 6 (95% CI; 5.16-6.83) and 16 months (95% CI; 13.07-18.93) respectively in patients treated with concurrent chemoradiotherapy and consolidation chemotherapy. Relative to the control cohort endoglin (p = 0.000) and TNFα (p = 0.000) levels were significantly lower; however VEGF (p = 0.030) levels were higher in the patient group. In contrast, there were no significant change in IL-6 levels and the plasma apoptotic markers M65 (p = 0.085) and M30 (p = 0.292). In separate log rank tests, these biological markers did not correlate with survival.

DISCUSSION AND CONCLUSION

In HGG, a significant decrease in endoglin and TNFα levels was observed, while VEGF levels were significantly increased postoperatively. However, with the power from this patient population, no correlation with survival was observed.

Post-radiation increase in VEGF enhances glioma cell motility in vitro

Background

Glioblastoma multiforme (GBM) is among the most lethal of all human tumors, with frequent local recurrences after radiation therapy (RT). The mechanism accounting for such a recurrence pattern is unclear. It has classically been attributed to local recurrence of treatment-resistant cells. However, accumulating evidence suggests that additional mechanisms exist that involve the migration of tumor or tumor stem cells from other brain regions to tumor bed. VEGFs are well-known mitogens and can be up-regulated after RT. Here, we examine the effect of irradiation-induced VEGF on glioma cell motility.

Materials and methods

U251 and LN18 cell lines were used to generate irradiated-conditioned medium (IR-CM). At 72 h after irradiation, the supernatants were harvested. VEGF level in IR-CM was quantified by ELISA, and expression levels for VEGF mRNA were detected by RT-PCR. In vitro cancer cell motility was measured in chambers coated with/without Matrigel and IR-CM as a cell motility enhancer and a VEGF antibody as a neutralizer of VEGF bioactivity. Immunoblots were performed to evaluate the activity of cell motility-related kinases. Proliferation of GBM cells after treatment was measured by flow cytometry.

Results

Irradiation increased the level of VEGF mRNA that was mitigated by pre-RT exposure to Actinomycin D. U251 glioma cell motility (migration and invasion) was enhanced by adding IR-CM to un-irradiated cells (174.9 ± 11.4% and 334.2 ± 46% of control, respectively). When we added VEGF antibody to IR-CM, this enhanced cell motility was negated (110.3 ± 12.0% and 105.7 ± 14.0% of control, respectively). Immunoblot analysis revealed that IR-CM increased phosphorylation of VEGF receptor-2 (VEGFR2) secondary to an increase in VEGF, with a concomitant increase of phosphorylation of the downstream targets (Src and FAK). Increased phosphorylation was mitigated by adding VEGF antibody to IR-CM. There was no difference in the mitotic index of GBM cells treated with and without IR-CM and VEGF.

Conclusions

These results indicate that cell motility can be enhanced by conditioned medium from irradiated cells in vitro through stimulation of VEGFR2 signaling pathways and suggest that this effect involves the secretion of radiation-induced VEGF, leading to an increase in glioma cell motility.

MMP-2 siRNA inhibits radiation-enhanced invasiveness in glioma cells

Background

Our previous work and that of others strongly suggests a relationship between the infiltrative phenotype of gliomas and the expression of MMP-2. Radiation therapy, which represents one of the mainstays of glioma treatment, is known to increase cell invasion by inducing MMP-2. Thus, inhibition of MMP-2 provides a potential means for improving the efficacy of radiotherapy for malignant glioma.

Methodology/Principal Findings

We have tested the ability of a plasmid vector-mediated MMP-2 siRNA (p-MMP-2) to modulate ionizing radiation-induced invasive phenotype in the human glioma cell lines U251 and U87. Cells that were transfected with p-MMP-2 with and without radiation showed a marked reduction of MMP-2 compared to controls and pSV-transfected cells. A significant reduction of proliferation, migration, invasion and angiogenesis of cells transfected with p-MMP-2 and in combination with radiation was observed compared to controls. Western blot analysis revealed that radiation-enhanced levels of VEGF, VEGFR-2, pVEGFR-2, p-FAK, and p-p38 were inhibited with p-MMP-2-transfected cells. TUNEL staining showed that radiation did not induce apoptosis in U87 and U251 cells while a significant increase in TUNEL-positive cells was observed when irradiated cells were simultaneously transfected with p-MMP-2 as compared to controls. Intracranial tumor growth was predominantly inhibited in the animals treated with p-MMP-2 alone or in combination with radiation compared to controls.

Conclusion/Significance

MMP-2 inhibition, mediated by p-MMP-2 and in combination with radiation, significantly reduced tumor cell migration, invasion, angiogenesis and tumor growth by modulating several important downstream signaling molecules and directing cells towards apoptosis. Taken together, our results demonstrate the efficacy of p-MMP-2 in inhibiting radiation-enhanced tumor invasion and progression and suggest that it may act as a potent adjuvant for radiotherapy in glioma patients.

Randomized double-blind placebo-controlled trial of bevacizumab therapy for radiation necrosis of the central nervous system

PURPOSE

To conduct a controlled trial of bevacizumab for the treatment of symptomatic radiation necrosis of the brain.

METHODS AND MATERIALS

A total of 14 patients were entered into a placebo-controlled randomized double-blind study of bevacizumab for the treatment of central nervous system radiation necrosis. All patients were required to have radiographic or biopsy proof of central nervous system radiation necrosis and progressive neurologic symptoms or signs. Eligible patients had undergone irradiation for head-and-neck carcinoma, meningioma, or low- to mid-grade glioma. Patients were randomized to receive intravenous saline or bevacizumab at 3-week intervals. The magnetic resonance imaging findings 3 weeks after the second treatment and clinical signs and symptoms defined the response or progression.

RESULTS

The volumes of necrosis estimated on T(2)-weighted fluid-attenuated inversion recovery and T(1)-weighted gadolinium-enhanced magnetic resonance imaging scans demonstrated that although no patient receiving placebo responded (0 of 7), all bevacizumab-treated patients did so (5 of 5 randomized and 7 of 7 crossover) with decreases in T(2)-weighted fluid-attenuated inversion recovery and T(1)-weighted gadolinium-enhanced volumes and a decrease in endothelial transfer constant. All bevacizumab-treated patients-and none of the placebo-treated patients-showed improvement in neurologic symptoms or signs. At a median of 10 months after the last dose of bevacizumab in patients receiving all four study doses, only 2 patients had experienced a recurrence of magnetic resonance imaging changes consistent with progressive radiation necrosis; one patient received a single additional dose of bevacizumab and the other patient received two doses.

CONCLUSION

The Class I evidence of bevacizumab efficacy from the present study in the treatment of central nervous system radiation necrosis justifies consideration of this treatment option for people with radiation necrosis secondary to the treatment of head-and-neck cancer and brain cancer.

Low-dose X-irradiation promotes mineralization of fracture callus in a rat model

OBJECTIVES

This study investigated the hypothesized beneficial effect of low-dose irradiation (LDI) on fracture callus mineralization in a rat model.

METHODS

Seventy-two male Sprague-Dawley rats were averagely randomized into LDI group (rats treated with LDI) and SHAM group (rats treated with sham irradiation). Right after either LDI or sham irradiation, a standardized closed fracture on the right femur was established. At 2, 3 and 4 weeks postfracture, 12 rats in each group were euthanized. Fracture callus was assessed by using radiography and MicroCT for callus bridging, peripheral quantitative computed tomography (pQCT) for quantifying bone mineral content (BMC) and cross sectional area (CSA), confocal laser scanning microscopy for measuring area fraction of fluorescence labeling (AFFL) and four-point bending test for examining mechanical properties.

RESULTS

The CSA and AFFL were found to be 22 and 33% smaller in the LDI group compared to the SHAM group at 2 weeks (P<0.05 for both), whereas the BMC and AFFL were 15 and 34% higher in the LDI group at 3 weeks (P<0.05 for both). The changing patterns were consistent with the findings in 3-D MicroCT reconstructions. The mechanical parameters (Max-Load, Stiffness and Energy) were also 18, 30 and 24% higher in the LDI group than in the SHAM group at 3 weeks (P<0.05 for all). At 4 weeks, there was no difference found for all assessments between the two groups.

CONCLUSION

The results indicated LDI promoted mineralization at the stage of hard callus formation in a rat fracture model.

Cytokine and growth factor responses after radiotherapy for localized ependymoma

PURPOSE

To determine the time course and clinical significance of cytokines and peptide growth factors in pediatric patients with ependymoma treated with postoperative radiotherapy (RT).

METHODS AND MATERIALS

We measured 15 cytokines and growth factors (fibroblast growth factor, epidermal growth factor, vascular endothelial growth factor [VEGF], interleukin [IL]-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, interferon-gamma, tumor necrosis factor-alpha, granulocyte-macrophage colony-stimulating factor, monocyte chemoattractant protein-1, and macrophage inflammatory protein-alpha) from 30 patients before RT and 2 and 24 h, weekly for 6 weeks, and at 3, 6, 9, and 12 months after the initiation of RT. Two longitudinal models for the trend of log-transformed measurements were fitted, one during treatment and one through 12 months.

RESULTS

During RT, log IL-8 declined at a rate of -0.10389/wk (p = 0.0068). The rate of decline was greater (p = 0.028) for patients with an infratentorial tumor location. The decline in IL-8 after RT was significant when stratified by infratentorial tumor location (p = 0.0345) and more than one surgical procedure (p = 0.0272). During RT, the decline in log VEGF was significant when stratified by the presence of a ventriculoperitoneal shunt. After RT, the log VEGF declined significantly at a rate of -0.06207/mo. The decline was significant for males (p = 0.0222), supratentorial tumors (p = 0.0158), one surgical procedure (p = 0.0222), no ventriculoperitoneal shunt (p = 0.0005), and the absence of treatment failure (p = 0.0028).

CONCLUSION

The pro-inflammatory cytokine IL-8 declined significantly during RT and the decline differed according to tumor location. The angiogenesis factor VEGF declined significantly during the 12 months after RT. The decline was greater in males, those without a ventriculoperitoneal shunt, and in those with favorable disease factors, including one surgical procedure, supratentorial tumor location, and tumor control.

Practical approaches to proteomic biomarkers within prostate cancer radiotherapy trials

INTRODUCTION

Proteomic biomarkers may be useful for monitoring therapeutic response and to triage cancer patients to best therapy.

OBJECTIVES

In this review, we highlight the importance of specimen acquisition, preparation and analysis in radiotherapy proteomic studies. We also discuss practical approaches for the design and execution of clinical proteomic studies using our recent experience based on specimens accrued during prostate cancer radiation therapy.

DISCUSSION AND CONCLUSIONS

Numerous proteomic methods are being employed, including high-throughput mass spectrometry and immunoassays, and using solid tissues, blood and urine for analysis. Given the potential complexity of cytokine and other protein responses, there is a need to assess proteomic signatures within serial samples as longitudinal studies during a course of fractionated radiotherapy (RT).

Can Serum Markers Be Used to Predict Acute and Late Toxicity in Patients With Lung Cancer?

PURPOSE

To identify factors that are predictive of satisfactory acute and long-term pulmonary tolerance of definitive irradiation and, conversely, factors that are predictive of excessive impairment of pulmonary functions. To determine if there is any correlation between early elevation of biochemical markers obtained in blood of irradiated patients and subsequent pulmonary abnormalities as detected by clinical findings, pulmonary function tests, and/or radiographic findings of pneumonitis/fibrosis.

MATERIALS AND METHODS

This was a multi-institutional prospective trial sponsored by the Radiation Therapy Oncology Group. Eligible patients had surgically unresectable or medically inoperable stage II or III non-small cell lung cancer. Pretreatment evaluation included baseline dyspnea index (BDI) and pulmonary function tests (PFT). Radiation therapy consisted of once-daily treatment with 2 Gy to a total of 60 to 66 Gy. A quantitative nuclear medicine perfusion study was correlated to the radiation therapy portals to assess the proportion of lung irradiated. Blood for serum markers (surfactant apoprotein, procollagen type III, interleukin [IL]-1, interleukin-6, and tumor necrosis factor-alpha) was drawn prior to the beginning of radiation therapy and then weekly during treatment (at 10, 20, 30, 40, 50, and 60 Gy). Post-treatment follow-up included PFT every 3 months for 1 year and then annually. The BDI was reevaluated at the same intervals.

RESULTS

There were 127 analyzable patients. Squamous cell carcinoma was the predominant histology and 93% of the patients had AJCC stage III disease. The median survival time is 10.9 months with 43% of patients living 1 year and 10% living 3 years. Grade >or=2 acute lung toxicity was seen in 18% of patients; patients least likely to develop lung toxicity are those with undetectable levels of IL-6 at 10 Gy and diffusing capacity of the lung for carbon monoxide percent (DLCO%) >54. Patients most likely to develop acute toxicity are those with elevated IL-6 and age >60 years. Grade >or=2 late lung toxicity was seen in 30% of patients. Karnofsky performance status was the only pretreatment factor predictive of late lung toxicity. The proportion of lung within the irradiated field, BDI indices, physician-assessed baseline dyspnea, and baseline PFT were not predictive of pulmonary toxicity. Using grade >or=2 toxicity as an event, age >60 years, gender, and a surfactant level <797 at 20 Gy were predictive of late lung toxicity.

CONCLUSIONS

Elevated levels of serum IL-6 after 10 Gy of lung irradiation appear to predict grade >or=2 acute lung toxicity, and high serum levels of surfactant apoproteins at 20 Gy correlated with grade >or=2 late pulmonary toxicity. These findings need to be confirmed but could be useful in a model to predict risk of pulmonary injury with high doses of radiation. For future studies, it is necessary to evaluate serum markers at multiple time-points during treatment, and quality control is critical during the collection, storage, and analysis of these serum markers.

Recurrent late cerebral necrosis with aggressive characteristics after radiosurgical treatment of an arteriovenous malformation

✓Late cerebral radiation necrosis usually occurs within 3 years of stereotactic radiosurgery. The authors report on a case of recurrent radiation necrosis with rapid clinical deterioration and imaging findings resembling those of a malignant glioma. This 68-year-old man, who had a history of a left posterior temporal and thalamic arteriovenous malformation (AVM) treated with linear accelerator radiosurgery 13 years before presentation and complicated by radiation necrosis 11 years before presentation, exhibited new-onset mixed aphasia, right hemiparesis, and right hemineglect. Imaging studies demonstrated hemorrhage and an enlarging, heterogeneously enhancing mass in the region of the previously treated AVM. The patient was treated medically with corticosteroid agents, and stabilized temporarily. Unfortunately, his condition worsened precipitously soon thereafter, requiring the placement of a shunt for relief of obstructive hydrocephalus. Further surgical intervention was offered, but the patient’s family opted for hospice care instead. The patient died 10 weeks after initially presenting to the authors’ institution, and the results of an autopsy demonstrated radiation necrosis.

Symptomatic radiation necrosis can occur more than a decade after stereotactic radiosurgery, necessitating patient follow up during a longer period of time than currently practiced. Furthermore, there is a need for more careful reporting on the natural history of such cases to clarify the pathogenesis of very late and recurrent radiation necrosis after radiosurgery and to define patient groups with a higher risk for these entities.

Increased concentrations of transforming growth factor β1 and β2 in the plasma of patients with glioblastoma

Recently, several in vitro studies have demonstrated production of the potent immunosuppressive cytokine transforming growth factor beta (TGF-beta)2 in glioblastoma cell lines. Systematic studies of the concentration of TGF-beta isoforms in the plasma of patients harboring intracerebral tumors do not exist. In the present study, the concentrations of TGF-beta1 and TGF-beta2 in platelet-poor plasma of 21 patients with glioblastoma before and after extensive resection were measured by specific ELISA systems and related to survival. The plasma concentrations of latent TGF-beta1 of patients with glioblastoma prior to surgery were significantly higher in comparison to healthy control probands, but not to patients with multiple sclerosis (MS). Furthermore, latent TGF-beta2 was found to be significantly increased in the plasma of patients with glioblastoma in comparison to healthy control probands and patients with MS. After extensive resection of the tumor, the value of latent TGF-beta2 evidently decreased. Interestingly, the concentration of latent TGF-beta2 prior to surgery was correlated with survival and a strong relationship was found between the survival and the difference of latent TGF-beta2 levels prior to surgery minus the TGF-beta2 concentrations 7 days after surgery. A higher difference in these plasma concentrations >6 ng/ml vs. <6 ng/ml clearly correlates with a longer survival time. In conclusion, this study suggests that glioblastoma does secret TGF-beta2 in vivo and that TGF-beta2 may play an important role in glioblastoma patients.

Radiation-enhanced vascular endothelial growth factor (VEGF) secretion in glioblastoma multiforme cell lines--a clue to radioresistance?

OBJECTIVE

Postoperative radiotherapy is standard treatment for patients with a glioblastoma multiforme (GBM). However, a GBM is radioresistant and almost always recurs, even after a high dose of radiation. A GBM is characterized by its extensive neo-angiogenesis, which can be attributed to the high levels of vascular endothelial growth factor (VEGF). The scope of this study is to investigate the VEGF secretion by GBM cells with different radiosensitivity after irradiation.

METHODS

Three human GBM cell lines (U251, U251-NG2 and U87) were irradiated with single doses of 0, 5, 10 and 20 Gy of gamma-rays from a (137)Cs source. VEGF levels in medium were measured by ELISA at 24, 48 and 72 h after radiation. Cell survival was measured by the XTT assay 7 days after irradiation.

RESULTS

Following single dose radiation, the VEGF levels showed a dose dependent increase in U251, U251-NG2 and U87 glioma cells. Both base-line and radiation-enhanced VEGF levels were about 10-fold higher in U87 compared to U251 and U251-NG2 cells. In addition, in the XTT assay, the U87 was more radioresistant than both U251 and U251-NG2 cell lines (dose modifying factor (DMF) = 1.6 and 1.7 resp).

CONCLUSION

Irradiation enhanced VEGF secretion in all three tested glioma cell lines (up to eight times basal levels). It is tempting to associate the radiation-enhanced VEGF secretion with an increased angiogenic potential of the tumor, which may be a factor in radioresistance.

Anti-angiogenic Therapy in Pediatric Neuro-oncology

In order to grow, tissues require additional nutrients and oxygen as well as removal of waste products. Tumors achieve this by up-regulating angiogenic cytokines and/or down-regulating natural inhibitory proteins that allow neovascularization to proceed. Brain tumors continue to account for significant morbidity and mortality, in spite of significant advances in neurosurgical and radiation techniques and new chemotherapy combinations. As such, there is a real and immediate need for novel biologic therapies that can target these tumors. A number of new drugs that target different aspects of the angiogenic cascade have been identified and are now in clinical trials in children with primary brain tumors. In many of these pre-clinical and clinical studies, anti-angiogenic therapy has been well tolerated, has lacked many of the traditional toxicities of radiation and chemotherapy, does not require blood-brain barrier penetration, and targets a critical pathway in central nervous system tumor development. This review will discuss what angiogenesis is, how pediatric brain tumors regulate angiogenesis to obtain a vascular supply, what types of inhibitors are available, how different classes of inhibitors work, the types of resistance possible, how rapidly these inhibitors may work, and what surrogate markers of activity are available to follow response.

Time course of serum cytokines in patients receiving proton or combined photon/proton beam radiation for resectable but medically inoperable non-small-cell lung cancer

PURPOSE

We prospectively measured the levels of basic fibroblast growth factor (bFGF), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-10, and procollagen III peptide (P III P) in serum from non-small-cell lung cancer patients treated with photons combined with protons or protons alone. These factors were quantified because they may be extremely important in the development of side effects, and the treated volume integral dose may be crucial in inducing them.

METHODS

Of the 12 participating patients, 6 with squamous cell carcinoma (SCC) and 3 with adenocarcinoma received combined photon/proton beam radiation, whereas 2 with SCC and 1 with large-cell carcinoma (LCC) received only proton radiation. Mean age was 73.6 years. There were 4 male and 8 female patients with a mean smoking history of 87.0 packyears. Nine patients had Stage I, 2 had Stage II, and 1 had stage IIIA lung cancer. Serum samples were obtained at baseline and on Days 15, 30, 45, 60, 90, 120, 150, 180, and 210 after initiation of radiation therapy. Injury scores for pneumonitis and fibrosis based on computed tomography (CT) scans were assigned.

RESULTS

The percentage of lung volume irradiated was significantly less for patients treated with protons alone compared with those receiving photon plus proton therapy (p < 0.001). Injury scores were also lower for proton only treatment (p = 0.039). When evaluated collectively, bFGF, TNF-alpha, and IL-6 concentrations were significantly higher in the photon/proton group (p < 0.05 or less); radiation regimen, but not time after treatment initiation, was a significant factor in their levels. P III P level was also higher in the photon/proton patients (p < 0.001) and both radiation regimen (p = 0.027) and time after treatment (p = 0.019) had an impact.

CONCLUSIONS

Although significant changes occurred in some of the measured cytokines and P III P, it was the difference in the volume integral dose that occurred when protons were used alone vs. mixed photon/proton therapy that correlated with the incidence of pneumonitis and/or fibrosis. However, it cannot be ruled out that differences in cytokine levels before radiotherapy initiation may have contributed to the outcome.

p38 MAPK mediates gamma-irradiation-induced endothelial cell apoptosis, and vascular endothelial growth factor protects endothelial cells through the phosphoinositide 3-kinase-Akt-Bcl-2 pathway

Therapeutic radiation is widely used in cancer treatments. The success of radiation therapy depends not only on the radiosensitivity of tumor cells but also on the radiosensitivity of endothelial cells lining the tumor vasculature. Vascular endothelial growth factor (VEGF) plays a critical role in protecting endothelial cells against a number of antitumor agents including ionizing radiation. Strategies designed to overcome the survival advantage afforded to endothelial cells by VEGF might aid in enhancing the efficacy of radiation therapy. In this report we examined the signaling cascade(s) involved in VEGF-mediated protection of endothelial cells against gamma-irradiation. gamma-Irradiation-induced apoptosis of human dermal microvascular endothelial cells (HDMECs) was predominantly mediated through the p38 MAPK pathway as an inhibitor of p38 MAPK (PD169316), and dominant negative mutants of p38 MAPK could significantly enhance HDMEC survival against gamma-irradiation. Inhibition of the PI3K and MAPK pathways markedly up-regulated gamma-irradiation-mediated p38 MAPK activation resulting in enhanced HDMEC apoptosis. In contrast, VEGF-treated HDMECs were protected from gamma-irradiation-induced apoptosis predominantly through the PI3K/Akt pathway. Bcl-2 expression was markedly elevated in VEGF-treated HDMECs, and it was significantly inhibited by the PI3K inhibitor LY294002. HDMECs exposed to irradiation showed a significant decrease in Bcl-2 expression. In contrast, VEGF-stimulated HDMECs, when irradiated, maintained higher levels of Bcl-2 expression. Taken together our results suggest that gamma-irradiation induces endothelial cell apoptosis predominantly via the activation of p38 MAPK, and VEGF protects endothelial cells against gamma-irradiation predominantly via the PI3K-Akt-Bcl-2 signaling pathway.

Thrombospondin-1 treatment prevents growth of dormant lung micrometastases after surgical resection and curative radiation therapy of the primary tumor in human melanoma xenografts

PURPOSE

Intradermal D-12 human melanoma xenografts develop pulmonary micrometastases in BALB/c nu/nu mice, and these metastases are kept dormant for prolonged times, because the primary tumor secretes thrombospondin-1 (TSP-1) into the blood circulation of the host. In this study, we report on the development of macroscopic metastases after surgical resection and curative radiation treatment of the primary tumor, the mechanisms involved, and the effects of treating the host with exogenous TSP-1 after the eradication of the primary tumor.

METHODS AND MATERIALS

Xenografted tumors of the D-12 human melanoma were used as tumor model. Macroscopic metastases were scored by using a stereomicroscope. Micrometastases were detected by histologic examinations. Angiogenesis was studied by using an intradermal angiogenesis assay. Apoptotic endothelial cells were detected by immunohistochemistry by using an in situ apoptosis detection kit.

RESULTS

Surgical resection as well as curative radiation treatment of the primary tumor resulted in accelerated growth of dormant micrometastases. This growth could be prevented by treating the host with exogenous TSP-1 after the surgery or the irradiation. Endogenous and exogenous TSP-1 prevented metastatic growth by suppressing angiogenesis, i.e., by inducing apoptosis in activated endothelial cells adjacent to dormant micrometastases.

CONCLUSIONS

TSP-1 has antiangiogenic and antimetastatic effects that should be investigated further in clinical studies. Cancer patients with TSP-1-producing primary tumors may benefit from combined local treatment and antiangiogenic/antimetastatic treatment with TSP-1.

Analysis of Interleukin-1β-induced Cell Signaling Activation in Rat Hippocampus following Exposure to Gamma Irradiation

Among the many reported effects of irradiation in cells is activation of the stress-activated protein kinase, c-Jun N-terminal kinase (JNK), which has been shown to result in apoptotic cell death. The trigger that leads to JNK activation has not been identified, although, in rat hippocampus at least, irradiation-induced apoptosis has been coupled with increased accumulation of reactive oxygen species (ROS). Significantly, irradiation-induced changes in hippocampus are abrogated by treatment of rats with the polyunsaturated fatty acid, eicosapentaenoic acid (EPA). A close coupling between ROS accumulation and concentration of the pro-inflammatory cytokine, interleukin-1 beta (IL-1 beta) in hippocampus has been reported, and the evidence suggests that IL-1 beta may be responsible for the enhanced ROS production. Here we set out to assess the possibility that whole body gamma-irradiation increases IL-1 beta concentration in hippocampus and to investigate the consequences of such a change. We present evidence that reveals that the irradiation-induced increase in IL-1 beta concentration in hippocampus is accompanied by increased expression of IL-1 type I receptor and IL-1 accessory protein and increased activation of IL-1 receptor-activated kinase. These changes, which were coupled with increased activation of JNK and evidence of apoptotic cell death, were absent in hippocampus of rats that received EPA treatment. Significantly, EPA treatment enhanced hippocampal IL-10 concentration that was inversely correlated with IL-1 beta concentration. The data are consistent with the idea that EPA exerts anti-inflammatory and neuroprotective effects in the central nervous system.

The effect of ST2 gene product on anchorage-independent growth of a glioblastoma cell line, T98G

The ST2 gene, which is specifically induced by growth stimulation in fibroblasts, encodes interleukin-1 receptor-related proteins and is widely expressed in hematopoietic, helper T, and various cancer cells. However, the physiological as well as pathological functions of the ST2 gene products are not yet fully understood. In this study, we analyzed the expression of the ST2 gene in human glioma cell lines and human brain tumor samples with real-time polymerase chain reaction method, the results of which revealed that the expression level of the ST2 gene in glioma cell lines and glioblastoma samples is significantly lower than that in a fibroblastic cell line, TM12, and benign brain tumors, suggesting the reverse relationship between malignancy and ST2 expression. As we could not detect the soluble ST2 protein in the culture fluid of the T98G glioblastic cell line by ELISA, we established stable transformants of T98G that continuously produce and secrete the ST2 protein, in order to study the effect of the ST2 protein on malignancy. Although we could not detect a remarkable difference in proliferation between transformants and control cells in conventional tissue culture dishes, the efficiency of colony formation in soft agar was significantly decreased in the case of cells that continuously produce the ST2 protein. Furthermore, inhibition of colony formation in soft agar was observed in wild-type T98G cells when purified soluble ST2 protein was added to the culture, in a dose-dependent manner. Taken together, the results suggest that the expression of ST2 suppressed the anchorage-independent growth and malignancy.

The impact of TNF-alpha induction on therapeutic efficacy following high dose spatially fractionated (GRID) radiation

A variety of cytokines especially TNF-alpha and TGF-beta are known to be released in response to high dose radiation of tumors. However, these are not normally measurable in systemic circulation unless high levels of these cytokines are produced by tumor cells. This study was undertaken to see if circulating levels of these cytokines could be measured in the serum of patients treated with high dose spatially fractionated (GRID) radiation and to correlate the finding of these cytokines with clinical response to treatment. Thirty-four patients (31 patients had single treatment site and 3 patients had 2 treatment sites) treated with spatially fractionated (GRID) radiation were entered in this study. Serum samples were collected before treatment and at 24, 48 and 72 hours after GRID radiation. Sandwich enzyme linked immunosorbent assay (ELISA) was performed to estimate the levels of TNF-alpha and activated TGF-beta1 proteins. Seven of 37 patients studied had no TNF-alpha protein before treatment but showed induction of TNF-alpha after GRID radiation. Three patients showed faint basal level of TNF-alpha protein before treatment and these levels were induced after treatment. Three patients showed a basal level of TNF-alpha protein before treatment and these levels decreased after treatment. In 21 cases no TNF-alpha protein was detected before or after treatment at the time points measured. In the case of TGF-beta1 protein, 2 patients showed no TGF-beta1 protein before GRID radiation and an induction of TGF-beta1 protein was observed after treatment. Seven patients showed basal level of TGF-beta1 protein prior to treatment and these levels were induced after treatment. Seventeen patients showed a basal level of TGF-beta1 protein before treatment and these levels decreased after treatment. In 8 cases no TGF-beta1 protein was detected before or after treatment. Complete clinical response (CR) to GRID therapy was seen in 12/37 (32%) treatment sites and partial response (PR) in 18/37 (49%) treatment sites. A strong correlation was observed between clinical CR rate and TNF-alpha induction. The rate of CR was 6/10 (60%) in patients where TNF-alpha was induced as compared to 6/27 (23%) treatment sites in patients where TNF-alpha induction was not seen (p = 0.029). No significant correlation with CR rate and TGF-beta1 induction (44% vs. 28%, p = 0.36) was observed. High dose spatially fractionated (GRID) radiation results in significant induction of TNF-alpha that can be measured in serum of some patients 24 72 hours after radiation. Complete tumor response strongly correlated with the induction of TNF-alpha levels in the serum.

Effect of preoperative radiotherapy on matrilysin gene expression in rectal cancer

Matrilysin, a member of matrix metalloproteinase family, is believed to play a significant role in the growth and proliferation of colon cancer cells. Overexpression of the matrilysin gene has been shown to correlate with Dukes' stage and increased metastatic potential in colorectal cancer. The aim of this study was to evaluate the effect of preoperative high-dose radiotherapy (25 Gy in five fractions over 5 days) on matrilysin (MMP-7) gene expression, in patients with resectable rectal cancer, by a quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Biopsy samples of tumour (n=30) and distant normal mucosa (n=12) from 15 patients were obtained pre- and post-radiotherapy. Messenger (m)RNA was extracted from all of the tissue samples and reverse transcribed to double-stranded cDNA. Quantitative RT-PCR was performed to study the effect of preoperative radiotherapy on matrilysin gene expression in both the tumour and normal mucosal specimens. Matrilysin mRNA values were expressed relative to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) for each sample. In 14 out of 15 cases, matrilysin mRNA was detected in the cancerous tissue. Although all six normal mucosal specimens expressed matrilysin mRNA, the levels were approximately 10-fold lower compared with those seen in the paired tumour samples. Preoperative radiotherapy led to a significant 6- to 7-fold increase (P=0.001) in the expression of matrilysin mRNA in rectal cancer tissue. In contrast, there was no significant change in the matrilysin mRNA expression of normal mucosal specimens post-radiotherapy. Preoperative high-dose radiotherapy upregulates matrilysin gene expression in rectal cancer. Matrilysin inhibition may be a useful preventive or therapeutic adjunct to radiotherapy in rectal cancer.

Fulminant radiation-induced necrosis after stereotactic radiation therapy to the posterior fossa. Case report and review of the literature

The problem of radiation-induced necrosis of normal brain surrounding the target area has been a major catalyst for the development of stereotactically focused radiation therapy. According to current opinion, the effects of stereotactic irradiation are confined to the region targeted. The authors present a case in which the administration of a conventional dose of stereotactically focused irradiation for treatment of a pilocytic astrocytoma produced fulminant necrosis that necessitated a combination of intensive surgical and medical management, after which the patient improved over the course of 1 year. Concomitant with his improvement, the initially remarkable findings on magnetic resonance imaging gradually resolved. In this presentation the authors emphasize the need to evaluate alternatives carefully before a decision is made to administer therapeutic irradiation. Furthermore, they explore the roles that target, host, and dosage factors play in hypersensitivity to radiation injury, the detection of these factors before treatment, and the administration of radioprotective agents. With the growing use of stereotactically focused irradiation as a primary treatment modality for a variety of neurosurgical conditions, it is important to be cognizant of its uncommon but potentially lethal side effects. A cooperative multicenter database in which the outcomes and morbidity following stereotactic irradiation are recorded is essential to the detection of relatively uncommon but severe complications such as those observed in this case.

Increased serum levels of basic fibroblast growth factor in lung cancer patients: relevance to response of therapy and prognosis

Angiogenesis is controlled by inhibitors and angiogenic factors. Among these, basic fibroblast growth factor (bFGF) is closely involved in cancer proliferation and has been related to progression and prognosis of various cancers, including lung cancer. To evaluate the role of bFGF, we measured serum levels of bFGF from healthy controls (Ctrl) and 106 patients with lung cancer, including 31 adenocarcinomas (AD), 29 squamous cell carcinomas (SQ), and 46 small cell carcinomas (SCLC), by enzyme-linked immunosorbent assays. Moreover, we evaluated the relationship between serum levels of bFGF and clinical outcome. Serum levels of bFGF in AD, SQ, SCLC, and Ctrl were 7.6 (0.5-32.5) (median (range)), 7.4 (0.5-36.7), 7.1 (0.5-34.8) and 3.0 (1.5-6.0) pg/ml, respectively (P<0.05). Serum bFGF levels did not differ between clinical stages in non-small cell lung cancer (NSCLC; AD+SQ). In SCLC, we found a significant difference in serum levels of bFGF between chemotherapy (and/or radiotherapy) responders (complete response+partial response) and non-responders (no change+progressive disease) (9.2 (0.6-34.8), 4.4 (0.5-17.4) pg/ml, respectively (P=0.018)), whereas there was no difference in NSCLC. Moreover, serum bFGF levels in SCLC patients had significant impact in prognosis by uni and multivariate analysis (P=0.014, 0.018, respectively). We concluded that bFGF has an important role in the prognosis of patients with SCLC.

Assessment of alterations in gene expression in recurrent malignant glioma after radiotherapy using complementary deoxyribonucleic acid microarrays

OBJECTIVE

We used complementary deoxyribonucleic acid expression microarrays to assess the effects of radiotherapy on gene expression in glioblastoma multiforme. We hypothesized that postradiation recurrent tumors may demonstrate alterations in gene expression from the primary tumor specimen.

METHODS

Patients were diagnosed with glioblastoma multiforme at resection of the initial tumor, and they received 60 Gy of fractionated radiotherapy before recurrence. Ribonucleic acid samples from both the primary and the postradiation recurrent tumor in each patient were screened and compared using complementary deoxyribonucleic acid expression arrays and Northern blot analysis.

RESULTS

Messenger ribonucleic acid levels of growth factors participating in paracrine loops, such as vascular endothelial growth factor and platelet-derived growth factor receptor beta, were decreased in postradiation recurrent tumors as compared with primary tumors in three of four patients. However, messenger ribonucleic acid levels of growth factors involved in autocrine loops, such as epidermal growth factor receptor, platelet-derived growth factor alpha, platelet-derived growth factor A, and basic fibroblast growth factor, were decreased in two of four, two of four, three of four, and three of four patients' recurrent tumors, respectively. Microvessel counts demonstrated that blood vessel growth was decreased significantly in postradiation recurrent tumor specimens.

CONCLUSION

After radiotherapy of glioblastoma multiforme, levels of paracrine-acting growth factors are diminished in correspondence with the reduction in vascular density. In contrast, growth factors that participate in autocrine loops demonstrate elevated levels of gene expression. These results suggest that maintenance of autocrine loops may be important in tumor regrowth after radiotherapy.