The Oncogene Metadherin Modulates the Apoptotic Pathway Based on the Tumor Necrosis Factor Superfamily Member TRAIL (Tumor Necrosis Factor-related Apoptosis-inducing Ligand) in Breast Cancer.

Metadherin (MTDH), the newly discovered gene, is overexpressed in more than 40% of breast cancers. Recent studies have revealed that MTDH favors an oncogenic course and chemoresistance. With a number of breast cancer cell lines and breast tumor samples, we found that the relative expression of MTDH correlated with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) sensitivity in breast cancer. In this study, we found that knockdown of endogenous MTDH cells sensitized the MDA-MB-231 cells to TRAIL-induced apoptosis both in vitro and in vivo. Conversely, stable overexpression of MTDH in MCF-7 cells enhanced cell survival with TRAIL treatment. Mechanically, MTDH down-regulated caspase-8, decreased caspase-8 recruitment into the TRAIL death-inducing signaling complex, decreased caspase-3 and poly(ADP-ribose) polymerase-2 processing, increased Bcl-2 expression, and stimulated TRAIL-induced Akt phosphorylation, without altering death receptor status. In MDA-MB-231 breast cancer cells, sensitization to TRAIL upon MTDH down-regulation was inhibited by the caspase inhibitor Z-VAD-fmk (benzyloxycarbonyl-VAD-fluoromethyl ketone), suggesting that MTDH depletion stimulates activation of caspases. In MCF-7 breast cancer cells, resistance to TRAIL upon MTDH overexpression was abrogated by depletion of Bcl-2, suggesting that MTDH-induced Bcl-2 expression contributes to TRAIL resistance. We further confirmed that MTDH may control Bcl-2 expression partly by suppressing miR-16. Collectively, our results point to a protective function of MTDH against TRAIL-induced death, whereby it inhibits the intrinsic apoptosis pathway through miR-16-mediated Bcl-2 up-regulation and the extrinsic apoptosis pathway through caspase-8 down-regulation.

Effect of RasGAP N2 fragment-derived peptide on tumor growth in mice.

Peptides that interfere with the natural resistance of cancer cells to genotoxin-induced apoptosis may improve the efficacy of anticancer regimens. We have previously reported that a cell-permeable RasGAP-derived peptide (TAT-RasGAP(317-326)) specifically sensitizes tumor cells to genotoxin-induced apoptosis in vitro. Here, we examined the in vivo stability of a protease-resistant D-form of the peptide, RI.TAT-RasGAP(317-326), and its effect on tumor growth in nude mice bearing subcutaneous human colon cancer HCT116 xenograft tumors. After intraperitoneal injection, RI.TAT-RasGAP(317-326) persisted in the blood of nude mice for more than 1 hour and was detectable in various tissues and subcutaneous tumors. Tumor-bearing mice treated daily for 7 days with RI.TAT-RasGAP(317-326) (1.65 mg/kg body weight) and cisplatin (0.5 mg/kg body weight) or doxorubicin (0.25 mg/kg body weight) displayed reduced tumor growth compared with those treated with either genotoxin alone (n = 5-7 mice per group; P = .004 and P = .005, respectively; repeated measures analysis of variance [ANOVA, two-sided]). This ability of the RI.TAT-RasGAP(317-326) peptide to enhance the tumor growth inhibitory effect of cisplatin was still observed at peptide doses that were at least 150-fold lower than the dose lethal to 50% of mice. These findings provide the proof of principle that RI.TAT-RasGAP(317-326) may be useful for improving the efficacy of chemotherapy in patients.

Prospective study of insulin-like growth factor-I, insulin-like growth factor-binding protein 3, genetic variants in the IGF1 and IGFBP3 genes and risk of coronary artery disease.

Although experimental studies have suggested that insulin-like growth factor I (IGF-I) and its binding protein IGFBP-3 might have a role in the aetiology of coronary artery disease (CAD), the relevance of circulating IGFs and their binding proteins in the development of CAD in human populations is unclear. We conducted a nested case-control study, with a mean follow-up of six years, within the EPIC-Norfolk cohort to assess the association between circulating levels of IGF-I and IGFBP-3 and risk of CAD in up to 1,013 cases and 2,055 controls matched for age, sex and study enrolment date. After adjustment for cardiovascular risk factors, we found no association between circulating levels of IGF-I or IGFBP-3 and risk of CAD (odds ratio: 0.98 (95% Cl 0.90-1.06) per 1 SD increase in circulating IGF-I; odds ratio: 1.02 (95% Cl 0.94-1.12) for IGFBP-3). We examined associations between tagging single nucleotide polymorphisms (tSNPs) at the IGF1 and IGFBP3 loci and circulating IGF-I and IGFBP-3 levels in up to 1,133 cases and 2,223 controls and identified three tSNPs (rs1520220, rs3730204, rs2132571) that showed independent association with either circulating IGF-I or IGFBP-3 levels. In an assessment of 31 SNPs spanning the IGF1 or IGFBP3 loci, none were associated with risk of CAD in a meta-analysis that included EPIC-Norfolk and eight additional studies comprising up to 9,319 cases and 19,964 controls. Our results indicate that IGF-I and IGFBP-3 are unlikely to be importantly involved in the aetiology of CAD in human populations.

Combinations of vascular endothelial growth factor pathway inhibitors with metronomic chemotherapy: Rational and current status.

Chemotherapy given in a metronomic manner can be administered with less adverse effects which are common with conventional schedules such as myelotoxicity and gastrointestinal toxicity and thus may be appropriate for older patients and patients with decreased performance status. Efficacy has been observed in several settings. An opportunity to improve the efficacy of metronomic schedules without significantly increasing toxicity presents with the addition of anti-angiogenic targeted treatments. These combinations rational stems from the understanding of the importance of angiogenesis in the mechanism of action of metronomic chemotherapy which may be augmented by specific targeting of the vascular endothelial growth factor (VEGF) pathway by antibodies or small tyrosine kinase inhibitors. Combinations of metronomic chemotherapy schedules with VEGF pathway targeting drugs will be discussed in this paper.

Glucagon-like peptide-1 increases beta-cell glucose competence and proliferation by translational induction of insulin-like growth factor-1 receptor expression.

Glucagon-like peptide-1 (GLP-1) protects beta-cells against apoptosis, increases their glucose competence, and induces their proliferation. We previously demonstrated that the anti-apoptotic effect was mediated by an increase in insulin-like growth factor-1 receptor (IGF-1R) expression and signaling, which was dependent on autocrine secretion of insulin-like growth factor 2 (IGF-2). Here, we further investigated how GLP-1 induces IGF-1R expression and whether the IGF-2/IGF-1R autocrine loop is also involved in mediating GLP-1-increase in glucose competence and proliferation. We show that GLP-1 up-regulated IGF-1R expression by a protein kinase A-dependent translational control mechanism, whereas isobutylmethylxanthine, which led to higher intracellular accumulation of cAMP than GLP-1, increased both IGF-1R transcription and translation. We then demonstrated, using MIN6 cells and primary islets, that the glucose competence of these cells was dependent on the level of IGF-1R expression and on IGF-2 secretion. We showed that GLP-1-induced primary beta-cell proliferation was suppressed by Igf-1r gene inactivation and by IGF-2 immunoneutralization or knockdown. Together our data show that regulation of beta-cell number and function by GLP-1 depends on the cAMP/protein kinase A mediated-induction of IGF-1R expression and the increased activity of an IGF-2/IGF-1R autocrine loop.

Tumor-necrosis factor can enhance radio-antibody uptake in human colon carcinoma xenografts by increasing vascular permeability.

Marked differences in the tumor uptake of a 125I-labeled monoclonal antibody (MAb) directed against carcinoembryonic antigen (CEA) were observed in 4 serially transplanted human colorectal carcinomas in nude mice. A comparative study showed that elevated values of measurable tumor vascular parameters, such as permeability, blood flow and blood volume, correlated better with high MAb tumor uptake than the concentration of target antigen in the tumor. In an attempt to modify the vascular parameters and to determine if this could increase antibody uptake by the tumor, rhTNF alpha (TNF) was injected i.t. or i.v. and antibody localization experiments were performed immediately thereafter. Results showed that the permeability of the tumor vessels increased 8 to 10 fold 1 hr after i.t. injection of TNF as compared to control tumors injected with saline. Tumor uptake of 125I-labeled anti-CEA MAb, was 3 times higher 2 hr after i.v. injection and still 27% higher 22 hr later, as compared to results from controls. Intravenous injection of TNF simultaneously with the 125I-labeled anti-CEA MAb also resulted in a 2-fold increase in tumor uptake 4 hr after injection, but the increase was no longer significant 24 hr after injection. Interestingly after i.v. injection of TNF, the MAb concentration in the blood and other normal tissues, such as liver, kidneys, lungs and heart was decreased, resulting in significantly higher ratios of tumor to normal tissue. Taken together the results demonstrate that injection of TNF can increase tumor vascular permeability and improve radio-antibody uptake. This raises the possibility of increasing the radiation dose delivered by antibody to the tumor in the course of radioimmunotherapy.

Cellular mechanisms underlying the regulation of dendritic development by hepatocyte growth factor.

Acquisition of a mature dendritic morphology is critical for neural information processing. In particular, hepatocyte growth factor (HGF) controls dendritic arborization during brain development. However, the cellular mechanisms underlying the effects of HGF on dendritic growth remain elusive. Here, we show that HGF increases dendritic length and branching of rat cortical neurons through activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Activation of MAPK by HGF leads to the rapid and transient phosphorylation of cAMP response element-binding protein (CREB), a key step necessary for the control of dendritic development by HGF. In addition to CREB phosphorylation, regulation of dendritic growth by HGF requires the interaction between CREB and CREB-regulated transcription coactivator 1 (CRTC1), as expression of a mutated form of CREB unable to bind CRTC1 completely abolished the effects of HGF on dendritic morphology. Treatment of cortical neurons with HGF in combination with brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family that regulates dendritic development via similar mechanisms, showed additive effects on MAPK activation, CREB phosphorylation and dendritic growth. Collectively, these results support the conclusion that regulation of cortical dendritic morphology by HGF is mediated by activation of the MAPK pathway, phosphorylation of CREB and interaction of CREB with CRTC1.

BAFF binds to the tumor necrosis factor receptor-like molecule B cell maturation antigen and is important for maintaining the peripheral B cell population.

The tumor necrosis factor (TNF) family member B cell activating factor (BAFF) binds B cells and enhances B cell receptor-triggered proliferation. We find that B cell maturation antigen (BCMA), a predicted member of the TNF receptor family expressed primarily in mature B cells, is a receptor for BAFF. Although BCMA was previously localized to the Golgi apparatus, BCMA was found to be expressed on the surface of transfected cells and tonsillar B cells. A soluble form of BCMA, which inhibited the binding of BAFF to a B cell line, induced a dramatic decrease in the number of peripheral B cells when administered in vivo. Moreover, culturing splenic cells in the presence of BAFF increased survival of a percentage of the B cells. These results are consistent with a role for BAFF in maintaining homeostasis of the B cell population.

Fluence plays a critical role on the subsequent distribution of chemotherapy and tumor growth delay in murine mesothelioma xenografts pre-treated by photodynamic therapy.

BACKGROUND: The pre-conditioning of tumor vessels by low-dose photodynamic therapy (L-PDT) was shown to enhance the distribution of chemotherapy in different tumor types. However, how light dose affects drug distribution and tumor response is unknown. Here we determined the effect of L-PDT fluence on vascular transport in human mesothelioma xenografts. The best L-PDT conditions regarding drug transport were then combined with Lipoplatin(®) to determine tumor response. in vivo. Lasers Surg. Med. 47:323-330, 2015. © 2015 Wiley Periodicals, Inc. METHODS: Nude mice bearing dorsal skinfold chambers were implanted with H-Meso1 cells. Tumors were treated by Visudyne(®) -mediated photodynamic therapy with 100 mW/cm(2) fluence rate and a variable fluence (5, 10, 30, and 50 J/cm(2) ). FITC-Dextran (FITC-D) distribution was assessed in real time in tumor and normal tissues. Tumor response was then determined with best L-PDT conditions combined to Lipoplatin(®) and compared to controls in luciferase expressing H-Meso1 tumors by size and whole body bioluminescence assessment (n = 7/group). RESULTS: Tumor uptake of FITC-D following L-PDT was significantly enhanced by 10-fold in the 10 J/cm(2) but not in the 5, 30, and 50 J/cm(2) groups compared to controls. Normal surrounding tissue uptake of FITC-D following L-PDT was significantly enhanced in the 30 J/cm(2) and 50 J/cm(2) groups compared to controls. Altogether, the FITC-D tumor to normal tissue ratio was significantly higher in the 10 J/cm(2) group compared others. Tumor growth was significantly delayed in animals treated by 10 J/cm2-L-PDT combined to Lipoplatin(®) compared to controls. CONCLUSIONS: Fluence of L-PDT is critical for the optimal distribution and effect of subsequently administered chemotherapy. These findings have an importance for the clinical translation of the vascular L-PDT concept in the clinics. Lasers Surg. Med. 47:323-330, 2015.

RasGAP Shields Akt from Deactivating Phosphatases in Fibroblast Growth Factor Signaling but Loses This Ability Once Cleaved by Caspase-3.

Fibroblast growth factor receptors (FGFRs) are involved in proliferative and differentiation physiological responses. Deregulation of FGFR-mediated signaling involving the Ras/PI3K/Akt and the Ras/Raf/ERK MAPK pathways is causally involved in the development of several cancers. The caspase-3/p120 RasGAP module is a stress sensor switch. Under mild stress conditions, RasGAP is cleaved by caspase-3 at position 455. The resulting N-terminal fragment, called fragment N, stimulates anti-death signaling. When caspase-3 activity further increases, fragment N is cleaved at position 157. This generates a fragment, called N2, that no longer protects cells. Here, we investigated in Xenopus oocytes the impact of RasGAP and its fragments on FGF1-mediated signaling during G2/M cell cycle transition. RasGAP used its N-terminal Src homology 2 domain to bind FGFR once stimulated by FGF1, and this was necessary for the recruitment of Akt to the FGFR complex. Fragment N, which did not associate with the FGFR complex, favored FGF1-induced ERK stimulation, leading to accelerated G2/M transition. In contrast, fragment N2 bound the FGFR, and this inhibited mTORC2-dependent Akt Ser-473 phosphorylation and ERK2 phosphorylation but not phosphorylation of Akt on Thr-308. This also blocked cell cycle progression. Inhibition of Akt Ser-473 phosphorylation and entry into G2/M was relieved by PHLPP phosphatase inhibition. Hence, full-length RasGAP favors Akt activity by shielding it from deactivating phosphatases. This shielding was abrogated by fragment N2. These results highlight the role played by RasGAP in FGFR signaling and how graded stress intensities, by generating different RasGAP fragments, can positively or negatively impact this signaling.

Efficacy of tumor necrosis factor inhibitors in patients with ankylosing spondylitis

Objectives: This study aims to investigate the efficacy of tumor necrosis factor-alpha blockers such as infliximab, etanercept, and adalimumab in the treatment of ankylosing spondylitis. Patients and methods: The outcome of tumor necrosis factor-alpha blocker treatment was analyzed retrospectively in 59 patients with ankylosing spondylitis who were being treated in our clinic during last nine years. The patients' Assessment of SpondyloArthritis International Society (ASAS) 20 and ASAS 40 response rates, adverse drugs effects, and treatment compliance were evaluated. Results: ASAS 20 response was achieved by 89.8% of the patients in the third month, and by 93.2% in the sixth month. ASAS 40 response was achieved by 61% of the patients in the third and sixth month. No statistically significant difference was detected between the three tumor necrosis factor-alpha blockers with regards to the ASAS 40 response rates. Mild infections, observed in 31 of the patients, were the most common side effects. Serious side effect was observed in only one patient. The number of patients who withdrew from the treatment for various reasons was six.

Brain metastases in gastro-oesophageal adenocarcinoma: insights into the role of the human epidermal growth factor receptor 2 (HER2).

BACKGROUND: Gastro-oesophageal adenocarcinomas rarely metastasize to the central nervous system (CNS). The role of the human epidermal growth factor receptor 2 (HER2) in patients with these cancers and CNS involvement is presently unknown. PATIENTS AND METHODS: A multicentre registry was established to collect data from patients with gastro-oesophageal adenocarcinomas and CNS involvement both retrospectively and prospectively. Inclusion in the study required a predefined clinical data set, a central neuro-radiological or histopathological confirmation of metastatic CNS involvement and central assessment of HER2 by immunohistochemistry (IHC) and in situ hybridisation (ISH). In addition, expression of E-cadherin and DNA mismatch repair (MMR) proteins were assessed by IHC. RESULTS: One hundred patients fulfilled the inclusion criteria. The population's median age was 59 years (interquartile range: 54-68), of which 85 (85%) were male. Twenty-five patients were of Asian and 75 of Caucasian origin. HER2 status was positive in 36% (95% CI: 26.6-46.2) of cases. Median time from initial diagnosis to the development of brain metastases (BMets) or leptomeningeal carcinomatosis (LC) was 9.9 months (95% CI: 8.5-15.0). Median overall survival from diagnosis was 16.9 months (95% CI: 14.0-20.7) and was not related to the HER2 status. E-cadherin loss was observed in 9% of cases and loss of expression in at least one DNA MMR proteins in 6%. CONCLUSIONS: The proportion of a positive HER2 status in patients with gastro-oesophageal adenocarcinoma and CNS involvement was higher than expected. The impact of anti-HER2 therapies should be studied prospectively.