Vitamin E δ-tocotrienol Sensitizes Human Pancreatic Cancer Cells to TRAIL-induced Apoptosis Through Proteasome-Mediated Down-Regulation of c-FLIP

Background: Vitamin E δ-tocotrienol (VEDT), a vitamin E compound isolated from sources such as palm fruit and annatto beans, has been reported to have cancer chemopreventive and therapeutic effects. Methods: We report a novel function of VEDT in augmenting tumor necrosis factor-related apoptosis-inducing ligand- (TRAIL-) induced apoptosis in pancreatic cancer cells. The effects of VEDT were shown by its ability to trigger caspase-8-dependent apoptosis in pancreatic cancer cells. Results: When combined with TRAIL, VEDT significantly augmented TRAIL-induced apoptosis of pancreatic cancer cells. VEDT decreased cellular FLICE inhibitory protein (c-FLIP) levels without consistently modulating the expression of decoy death receptors 1, 2, 3 or death receptors 4 and 5. Enforced expression of c-FLIP substantially attenuated VEDT/TRAIL-induced apoptosis. Thus, c-FLIP reduction plays an important part in mediating VEDT/TRAIL-induced apoptosis. Moreover, VEDT increased c-FLIP ubiquitination and degradation but did not affect its transcription, suggesting that VEDT decreases c-FLIP levels through promoting its degradation. Of note, degradation of c-FLIP and enhanced TRAIL-induced apoptosis in pancreatic cancer cells were observed only with the anticancer bioactive vitamin E compounds δ-, γ-, and β-tocotrienol but not with the anticancer inactive vitamin E compounds α-tocotrienol and α-, β-, γ-, and δ-tocopherol. Conclusions: c-FLIP degradation is a key event for death receptor-induced apoptosis by anticancer bioactive vitamin E compounds in pancreatic cancer cells. Moreover, VEDT augmented TRAIL inhibition of pancreatic tumor growth and induction of apoptosis in vivo. Combination therapy with TRAIL agonists and bioactive vitamin E compounds may offer a novel strategy for pancreatic cancer intervention

Greco-2: A randomized, phase 2 study of stereotactic body radiation therapy (SBRT) in combination with rucosopasem (GC4711) in the treatment of locally advanced or borderline resectable nonmetastatic pancreatic cancer

Background: While treatment of pancreatic cancer has advanced, survival rates remain low. Stereotactic body radiotherapy (SBRT; high dose per fraction radiation) may exhibit improved clinical outcomes in locally advanced pancreatic cancer but carries potential gastrointestinal toxicity risks. Rucosopasem (GC4711) is one of a class of investigational selective dismutase mimetics that rapidly and specifically converts superoxide to hydrogen peroxide. Studies have shown that normal cells tolerate hydrogen peroxide fluxes better than cancer cells. As radiation response modifiers, dismutase mimetics have the potential to increase tumor control of SBRT without compromising radiation safety. In a pilot phase 1/2 trial in patients with pancreatic cancer, avasopasem, a dismutase mimetic related to rucosopasem, nearly doubled median overall survival in patients receiving SBRT vs placebo plus SBRT. Improvements versus placebo were also observed in local tumor control, time to metastases, and progression-free survival. Altogether, these data support the hypothesis that rucosopasem may improve survival and the benefit-risk ratio of SBRT by improving efficacy without increasing gastrointestinal toxicity. Methods: GRECO-2 is a phase 2, multicenter, randomized, double-blind, placebo-controlled study (NCT04698915) to determine the effect of adding rucosopasem to SBRT on overall survival in patients with borderline resectable or locally advanced, unresectable nonmetastatic pancreatic cancer following initial chemotherapy with a FOLFIRINOX-based regimen or a gemcitabine doublet. Approximately 160 patients will be randomized (approximately 35 sites) to receive rucosopasem 100 mg or placebo via IV infusion over 15 minutes, prior to each SBRT fraction (5 x 10 Gy). Patients judged to be resectable will undergo surgical exploration within 8 weeks after SBRT. The primary endpoint is overall survival. Secondary endpoints include progression-free survival, locoregional control, time to metastasis, surgical resection rate, RO resection rate, best overall response, in-field local response, and safety (acute and late toxicities). Exploratory endpoints include PRO-CTCAE and CA19-9 normalization

α-Tocopheryl succinate and TRAIL selectively synergise in induction of apoptosis in human malignant mesothelioma cells

Malignant mesothelioma (MM) is a fatal type of neoplasia with poor therapeutic prognosis, largely due to resistance to apoptosis. We investigated the apoptotic effect of alpha-tocopheryl succinate (alpha-TOS), a strong proapoptotic agent, in combination with the immunological apoptogen TNF-related apoptosis-inducing ligand (TRAIL) on both MM and nonmalignant mesothelial cells, since MM cells show low susceptibility to the clinically intriguing TRAIL. All MM cell lines tested were sensitive to alpha-TOS-induced apoptosis, and exerted high sensitivity to TRAIL in the presence of subapoptotic doses of the vitamin E analogue. Neither TRAIL or alpha-TOS alone or in combination caused apoptosis in nonmalignant mesothelial cells. Isobologram analysis of the cytotoxicity assays revealed a synergistic interaction between the two agents in MM cells and their antagonistic effect in nonmalignant mesothelial cells. TRAIL-induced apoptosis and its augmentation by alpha-TOS were inhibited by the caspase-8 inhibitor Z-IETD-FMK and the pan-caspase inhibitor Z-VAD-FMK. Activation of caspase-8 was required to induce apoptosis, which was amplified by alpha-TOS via cytochrome c release following Bid cleavage, with ensuing activation of caspase-9. Enhancement of TRAIL-induced apoptosis in MM cells by alpha-TOS was also associated with upregulation of the TRAIL cognate death receptors DR4 and DR5. Our results show that alpha-TOS and TRAIL act in synergism to kill MM cells via mitochondrial pathway, and are nontoxic to nonmalignant mesothelial cells. These findings are indicative of a novel strategy for treatment of thus far fatal MM

Evaluating the quality of psychosocial care in outpatient medical oncology settings using performance indicators

Abstract Objective: An American Psychosocial Oncology Society workgroup has developed indicators of the quality of psychosocial care that can be measured through review of medical records. The present report describes the first large-scale use of these indicators to evaluate psychosocial care in outpatient medical oncology settings. Methods: Medical records of 1660 colorectal, breast and non-small cell cancer patients first seen by a medical oncologist in 2006 at 11 practice sites in Florida were reviewed for performance on indicators of the quality of psychosocial care. Results: Assessment of emotional well-being was significantly less likely to be documented than assessment of pain (52 vs 87%, po0.001). A problem with emotional well-being was documented in 13% of records and evidence of action taken was documented in 58% of these records. Ten of eleven practice sites performed below an 85% threshold on each indicator of psychosocial care. Variability in assessment of emotional-well being was associated (po0.02) with practice site and patient gender and age while variability in assessment of pain was associated (po0.001) with practice site and cancer type. Conclusions: Findings illustrate how use of the psychosocial care indicators permits identification of specific practice sites and processes of care that should be targeted for quality improvement efforts. Additionally, findings demonstrate the extent to which routine assessment of emotional well-being lags behind routine assessment of pain in cancer patients

Deregulation of manganese superoxide dismutase (SOD2) expression and lymph node metastasis in tongue squamous cell carcinoma

<p>Abstract</p> <p>Background</p> <p>Lymph node metastasis is a critical event in the progression of tongue squamous cell carcinoma (TSCC). The identification of biomarkers associated with the metastatic process would provide critical prognostic information to facilitate clinical decision making. Previous studies showed that deregulation of manganese superoxide dismutase (SOD2) expression is a frequent event in TSCC and may be associated with enhanced cell invasion. The purpose of this study is to further evaluate whether the expression level of SOD2 is correlated with the metastatic status in TSCC patients.</p> <p>Methods</p> <p>We first examined the SOD2 expression at mRNA level on 53 TSCC and 22 normal control samples based on pooled-analysis of existing microarray datasets. To confirm our observations, we examined the expression of SOD2 at protein level on an additional TSCC patient cohort (n = 100), as well as 31 premalignant dysplasias, 15 normal tongue mucosa, and 32 lymph node metastatic diseases by immunohistochemistry (IHC).</p> <p>Results</p> <p>The SOD2 mRNA level in primary TSCC tissue is reversely correlated with lymph node metastasis in the first TSCC patient cohort. The SOD2 protein level in primary TSCC tissue is also reversely correlated with lymph node metastasis in the second TSCC patient cohort. Deregulation of SOD2 expression is a common event in TSCC and appears to be associated with disease progression. Statistical analysis revealed that the reduced SOD2 expression in primary tumor tissue is associated with lymph node metastasis in both TSCC patient cohorts examined.</p> <p>Conclusions</p> <p>Our study suggested that the deregulation of SOD2 in TSCC has potential predictive values for lymph node metastasis, and may serve as a therapeutic target for patients at risk of metastasis.</p

Murine Pancreatic Adenocarcinoma Reduces Ikaros Expression and Disrupts T Cell Homeostasis

Background Maintenance of T cell immune homeostasis is critical for adequate anti-tumor immunity. The transcription factor Ikaros is essential for lymphocyte development including T cells. Alterations in Ikaros expression occur in blood malignancies in humans and mice. In this study, we investigated the role of Ikaros in regulating T cell immune balance in pancreatic cancer mouse models. Methodology and Principal Findings Using our Panc02 tumor-bearing (TB) mouse model, western blot analysis revealed a reduction in Ikaros proteins while qRT-PCR showed no differences in Ikaros mRNA levels in TB splenocytes compared to control. Treatment of naïve splenocytes with the proteasomal inhibitor, MG132, stabilized Ikaros expression and prevented Ikaros downregulation by Panc02 cells, in vitro. Western blot analyses showed a reduction in protein phosphatase 1 (PP1) and protein kinase CK2 expression in TB splenocytes while CK2 activity was increased. Immunofluorescence microscopy revealed altered punctate staining of Ikaros in TB splenocytes. Flow cytometry revealed a significant decrease in effector CD4+ and CD8+ T cell percentages but increased CD4+CD25+ regulatory T cells in TB splenocytes. Similar alterations in T cell percentages, as well as reduced Ikaros and CK2 but not PP1 expression, were observed in a transgenic, triple mutant (TrM) pancreatic cancer model. Ikaros expression was also reduced in enriched TB CD3+ T cells. MG132 treatment of naïve CD3+ T cells stabilized Ikaros expression in the presence of Panc02 cells. Western blots showed reduced PP1 and CK2 expression in TB CD3+ T cells. Conclusions/Significance The results of this study suggest that the pancreatic tumor microenvironment may cause proteasomal degradation of Ikaros, possibly via dysregulation of PP1 and CK2 expression and activity, respectively. This loss of Ikaros expression may contribute to an imbalance in T cell percentages. Ikaros may potentially be a therapeutic target to restore T cell homeostasis in pancreatic cancer hosts, which may be critical for effective anti-tumor immunity

Manganese Superoxide Dismutase: Guardian of the Powerhouse

The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component