Long-Term Outcomes for Patients With Atypical or Malignant Meningiomas Treated With or Without Radiation Therapy: A 25-Year Retrospective Analysis of a Single-Institution Experience.

Purpose: Atypical (World Health Organization [WHO] grade 2) and malignant (WHO grade 3) meningiomas have high rates of local recurrence, and questions remain about the role of adjuvant radiation therapy (RT) for patients with WHO grade 2 disease. These patients frequently require salvage therapy, and optimal management is uncertain given limited prospective data. We report on the long-term outcomes for patients with atypical and malignant meningiomas treated with surgery and/or RT at our institution. Methods and Materials: Data were collected through a retrospective chart review for all patients with WHO grade 2 or 3 meningiomas treated with surgery and/or RT at our institution between January 1992 and March 2017. Progression-free survival (PFS) and overall survival (OS) were described using the KaplanMeier estimator. The outcomes in the subgroups were compared with a log-rank test. A Cox proportional hazards model was used for the univariable and multivariable analyses of predictors of PFS. Results: A total of 66 patients were included in this analysis. The median follow-up was 12.4 years overall and 8.6 years among surviving patients. Fifty-two patients (78.8%) had WHO grade 2 meningiomas, and 14 patients (21.2%) had WHO grade 3 disease. Thirty-six patients (54.5%) were treated with surgery alone, 28 patients (42.4%) with surgery and adjuvant RT, and 2 patients (3%) with RT alone. Median PFS and OS were 3.2 years and 8.8 years, respectively. PFS was significantly improved with adjuvant RT compared with surgery alone (hazard ratio, 0.36; 95% confidence interval, 0.18-0.70). Patients with Ki-67 index >10% showed a trend toward worse PFS compared with patients with Ki-67 ≤10% (hazard ratio, 0.51; 95% confidence interval, 0.25-1.04). No significant differences in PFS or OS were observed with respect to Simpson or WHO grade. Conclusions: For patients with atypical or malignant meningiomas, adjuvant RT was associated with significantly improved PFS, and Ki-67 index >10% was associated with a trend toward worse PFS. Given the long-term survival, high recurrence rates, and efficacy of salvage therapy, patients with atypical and malignant meningiomas should be monitored systematically long after initial treatment.

Sensitization of Endothelial Cells to Ionizing Radiation Exacerbates Delayed Radiation Myelopathy in Mice.

Delayed radiation myelopathy is a rare, but significant late side effect from radiation therapy that can lead to paralysis. The cellular and molecular mechanisms leading to delayed radiation myelopathy are not completely understood but may be a consequence of damage to oligodendrocyte progenitor cells and vascular endothelial cells. Here, we aimed to determine the contribution of endothelial cell damage to the development of radiation-induced spinal cord injury using a genetically defined mouse model in which endothelial cells are sensitized to radiation due to loss of the tumor suppressor p53. Tie2Cre; p53FL/+ and Tie2Cre; p53FL/- mice, which lack one and both alleles of p53 in endothelial cells, respectively, were treated with focal irradiation that specifically targeted the lumbosacral region of the spinal cord. The development of hindlimb paralysis was followed for up to 18 weeks after either a 26.7 Gy or 28.4 Gy dose of radiation. During 18 weeks of follow-up, 83% and 100% of Tie2Cre; p53FL/- mice developed hindlimb paralysis after 26.7 and 28.4 Gy, respectively. In contrast, during this period only 8% of Tie2Cre; p53FL/+ mice exhibited paralysis after 28.4 Gy. In addition, 8 weeks after 28.4 Gy the irradiated spinal cord from Tie2Cre; p53FL/- mice showed a significantly higher fractional area positive for the neurological injury marker glial fibrillary acidic protein (GFAP) compared with the irradiated spinal cord from Tie2Cre; p53FL/+ mice. Together, our findings show that deletion of p53 in endothelial cells sensitizes mice to the development of delayed radiation myelopathy indicating that endothelial cells are a critical cellular target of radiation that regulates myelopathy.

Characterization of cardiovascular injury in mice following partial-heart irradiation with clinically relevant dose and fractionation.

BACKGROUND AND PURPOSE: Late cardiac toxicity is a major side effect of radiation therapy (RT) for breast cancer. We developed and characterized a mouse model of radiation-induced heart disease that mimics the dose, fractionation, and beam arrangement of left breast and chest wall RT. MATERIAL AND METHODS: Female wild-type (C57BL6/J) and atherosclerosis-prone apolipoprotein E-deficient (ApoE-/-) mice (on a C57BL/6J background) on regular chow were treated with 2 Gy × 25 fractions of partial-heart irradiation via opposed tangential beams to the left chest wall. The changes in myocardial perfusion and cardiac function of C57BL/6J mice were examined by single-photon emission computed tomography (SPECT) and echocardiography, respectively. In addition to SPECT and echocardiography, the formation of calcified plaques and changes in cardiac function of ApoE-/- mice were examined by dual-energy microCT (DE-CT) and pressure-volume (PV) loop analysis, respectively. The development of myocardial fibrosis was examined by histopathology. RESULTS: Compared to unirradiated controls, irradiated C57BL/6J mice showed no significant changes by SPECT or echocardiography up to 18 months after 2 Gy × 25 partial-heart irradiation even though irradiated mice exhibited a modest increase in myocardial fibrosis. For ApoE-/- mice, 2 Gy × 25 partial-heart irradiation did not cause significant changes by SPECT, DE-CT, or echocardiography. However, PV loop analysis revealed a significant decrease in load-dependent systolic and diastolic function measures including cardiac output, dV/dtmax and dV/dt min 12 months after RT. CONCLUSIONS: Following clinically relevant doses of partial-heart irradiation in C57BL/6J and ApoE-/- mice, assessment with noninvasive imaging modalities such as echocardiography, SPECT, and DE-CT yielded no evidence of decreased myocardial perfusion and cardiac dysfunction related to RT. However, invasive hemodynamic assessment with PV loop analysis indicated subtle, but significant, changes in cardiac function of irradiated ApoE-/- mice. PV loop analysis may be useful for future preclinical studies of radiation-induced heart disease, especially if subtle changes in cardiac function are expected.

Long-term follow-up of patients with multiple myeloma treated with total body irradiation-Melphalan conditioning.

BACKGROUND AND OBJECTIVES: Since a study published in 2002 showed a survival advantage of melphalan-only conditioning for stem cell transplantation (HSCT) over melphalan-total body irradiation (mel-TBI) in patients with multiple myeloma (MM), most centers abandoned mel-TBI. Mel-TBI causes more early toxicity and is more complicated to administer, but we speculated it may result in longer term survival with radiation as an independent treatment modality. Therefore, we analyzed the long-term outcome of patients with MM who received mel-TBI as part of conditioning at our center. PATIENTS AND METHODS: From 1995 to 2013, 50 patients with MM underwent autologous HSCT at Tulane University Medical Center using mel-TBI conditioning. We used Kaplan-Meier survival analysis and compared our patients with data available from the Louisiana Tumor Registry. RESULTS: The mean survival of our patients was 70.98 months from time of transplant and 84.2 months from time of initial diagnosis. No differences were observed according to gender, ethnicity, or age at transplant. The expected median survival in a population-based registry (matched for age and year of treatment) was 27 months (P<.001). CONCLUSIONS: Total body irradiation in conjunction with melphalan as conditioning is feasible and can lead to long-term survival. More research is necessary to determine which patients benefit most. Mel-TBI should also be explored in conjunction with immunotherapy.

Patterns of Failure After Surgery for Non-Small-cell Lung Cancer Invading the Chest Wall.

INTRODUCTION: The patterns of failure after resection of non-small-cell lung cancer (NSCLC) invading the chest wall are not well documented, and the role of adjuvant radiation therapy (RT) is unclear, prompting the present analysis. MATERIALS AND METHODS: The present institutional review board-approved study evaluated patients who had undergone surgery from 1995 to 2014 for localized NSCLC invading the chest wall. Patients with superior sulcus tumors were excluded. The clinical outcomes were estimated using the Kaplan-Meier method and compared using a log-rank test. The prognostic factors were assessed using a multivariate analysis, and the patterns of failure were scored. RESULTS: Seventy-four patients were evaluated. Most patients had undergone lobectomy or pneumonectomy (85%) with en bloc chest wall resection (80%) and had pathologically node negative findings (81%). The surgical margins were positive in 10 patients (14%) and most commonly involved the chest wall (7 of 10). Adjuvant treatment included RT in 21 (28%) and chemotherapy in 28 (38%). A total of 24 local recurrences developed. The chest wall was a component of local disease recurrence in 19 of 24 cases (79%). The local control rate at 5 years for the entire population was 60% (95% confidence interval, 46%-74%). The local control rate was 74% with adjuvant RT versus 55% without RT (P = .43). On multivariate analysis, only resection less than lobectomy or pneumonectomy was associated with worse local control. The overall survival rate was 38% with RT versus 34% without RT (P = .59). CONCLUSION: Positive surgical margins and local disease recurrence were common after resection of NSCLC invading the chest wall. The primary pattern of failure was local recurrence in the chest wall. Adjuvant RT was not associated with improved local control or survival.

Regulation of IkappaB kinase-related kinases and antiviral responses by tumor suppressor CYLD.

The IkappaB kinase (IKK)-related kinases, IKKepsilon and TBK1, participate in the induction of type I interferons (IFNs) during viral infections. Deregulated activation of IKKepsilon and TBK1 also contributes to the abnormal cell survival and transformation. However, how these kinases are negatively regulated remains unclear. We show here that the tumor suppressor CYLD has an essential role in preventing aberrant activation of IKKepsilon/TBK1. CYLD deficiency causes constitutive activation of IKKepsilon/TBK1, which is associated with hyper-induction of IFNs in virus-infected cells. We further show that CYLD targets a cytoplasmic RNA sensor, RIG-I, and inhibits the ubiquitination of this IKKepsilon/TBK1 stimulator. Consistent with the requirement of ubiquitination in RIG-I function, CYLD potently inhibits RIG-I-mediated activation of the IFN-beta promoter. These findings establish CYLD as a key negative regulator of IKKepsilon/TBK1 and suggest a role for CYLD in the control of RIG-I ubiquitination.

Deubiquitinating enzyme CYLD negatively regulates RANK signaling and osteoclastogenesis in mice.

Osteoclastogenesis is a tightly regulated biological process, and deregulation can lead to severe bone disorders such as osteoporosis. The regulation of osteoclastic signaling is incompletely understood, but ubiquitination of TNF receptor-associated factor 6 (TRAF6) has recently been shown to be important in mediating this process. We therefore investigated the role of the recently identified deubiquitinating enzyme CYLD in osteoclastogenesis and found that mice with a genetic deficiency of CYLD had aberrant osteoclast differentiation and developed severe osteoporosis. Cultured osteoclast precursors derived from CYLD-deficient mice were hyperresponsive to RANKL-induced differentiation and produced more and larger osteoclasts than did controls upon stimulation. We assessed the expression pattern of CYLD and found that it was drastically upregulated during RANKL-induced differentiation of preosteoclasts. Furthermore, CYLD negatively regulated RANK signaling by inhibiting TRAF6 ubiquitination and activation of downstream signaling events. Interestingly, we found that CYLD interacted physically with the signaling adaptor p62 and thereby was recruited to TRAF6. These findings establish CYLD as a crucial negative regulator of osteoclastogenesis and suggest its involvement in the p62/TRAF6 signaling axis.

Regulation of early wave of germ cell apoptosis and spermatogenesis by deubiquitinating enzyme CYLD.

Spermatogenesis involves an early wave of germ cell apoptosis, which is required for maintaining the balance between germ cells and supporting Sertoli cells. However, the signaling mechanism regulating this apoptotic event is poorly defined. Here we show that genetic deficiency of Cyld, a recently identified deubiquitinating enzyme, attenuates the early wave of germ cell apoptosis and causes impaired spermatogenesis in mice. Interestingly, the loss of CYLD in testicular cells leads to activation of the transcription factor NF-kappaB and aberrant expression of antiapoptotic genes. We further show that CYLD negatively regulates a ubiquitin-dependent NF-kappaB activator, RIP1. CYLD binds to RIP1 and inhibits its ubiquitination and signaling function. These findings establish CYLD as a pivotal deubiquitinating enzyme (DUB) that regulates germ cell apoptosis and spermatogenesis and suggest an essential role for CYLD in controlling the RIP1/NF-kappaB signaling axis in testis.

Deubiquitinating enzyme CYLD negatively regulates the ubiquitin-dependent kinase Tak1 and prevents abnormal T cell responses.

The deubiquitinating enzyme CYLD has recently been implicated in the regulation of signal transduction, but its physiological function and mechanism of action are still elusive. In this study, we show that CYLD plays a pivotal role in regulating T cell activation and homeostasis. T cells derived from Cyld knockout mice display a hyperresponsive phenotype and mediate the spontaneous development of intestinal inflammation. Interestingly, CYLD targets a ubiquitin-dependent kinase, transforming growth factor-beta-activated kinase 1 (Tak1), and inhibits its ubiquitination and autoactivation. Cyld-deficient T cells exhibit constitutively active Tak1 and its downstream kinases c-Jun N-terminal kinase and IkappaB kinase beta. These results emphasize a critical role for CYLD in preventing spontaneous activation of the Tak1 axis of T cell signaling and, thereby, maintaining normal T cell function.

Deubiquitinating enzyme CYLD regulates the peripheral development and naive phenotype maintenance of B cells.

Deubiquitinating enzymes (DUB) form a family of cysteine proteases that digests ubiquitin chains and reverses the process of protein ubiquitination. Despite the identification of a large number of DUBs, their physiological functions remain poorly defined. Here we provide genetic evidence that CYLD, a recently identified DUB, plays a crucial role in regulating the peripheral development and activation of B cells. Disruption of the CYLD gene in mice results in B cell hyperplasia and lymphoid organ enlargement. The CYLD-deficient B cells display surface markers indicative of spontaneous activation and are hyperproliferative upon in vitro stimulation. When challenged with antigens, the CYLD(-/-) mice develop exacerbated lymphoid organ abnormalities and abnormal B cell responses. Although the loss of CYLD has only a minor effect on B cell development in bone marrow, this genetic deficiency disrupts the balance of peripheral B cell populations with a significant increase in marginal zone B cells. In keeping with these functional abnormalities, the CYLD(-/-) B cells exhibit constitutive activation of the transcription factor NF-kappaB due to spontaneous activation of IkappaB kinase beta and degradation of the NF-kappaB inhibitor IkappaBalpha. These findings demonstrate a critical role for CYLD in regulating the basal activity of NF-kappaB and maintaining the naive phenotype and proper activation of B cells.