Synergistic targeting of malignant pleural mesothelioma cells by MDM2 inhibitors and TRAIL agonists

Malignant Pleural Mesothelioma (MPM) is a chemoresistant tumor characterized by low rate of p53 mutation and upregulation of Murine Double Minute 2 (MDM2), suggesting that it may be effectively targeted using MDM2 inhibitors. In the present study, we investigated the anticancer activity of the MDM2 inhibitors Nutlin 3a (in vitro) and RG7112 (in vivo), as single agents or in combination with rhTRAIL.

In vitro studies were performed using MPM cell lines derived from epithelioid (ZL55, M14K), biphasic (MSTO211H) and sarcomatoid (ZL34) MPMs. In vivo studies were conducted on a sarcomatoid MPM mouse model.

In all the cell lines tested (with the exception of ZL55, which carries a biallelic loss-of-function mutation of p53), Nutlin 3a enhanced p21, MDM2 and DR5 expression, and decreased survivin expression. These changes were associated to cell cycle arrest but not to a significant induction of apoptosis. A synergistic pro-apoptotic effect was obtained through the association of rhTRAIL in all the cell lines harboring functional p53. This synergistic interaction of MDM2 inhibitor and TRAIL agonist was confirmed using a mouse preclinical model. Our results suggest that the combined targeting of MDM2 and TRAIL might provide a novel therapeutic option for treatment of MPM patients, particularly in the case of sarcomatoid MPM with MDM2 overexpression and functional inactivation of wild-type p53.

Abstract P1-13-02: Withdrawn

This abstract was withdrawn by the authors.

Approaches to modelling radioactive contaminations in forests - Overview and guidance

Modelling the radionuclide cycle in forests is important in case of contamination due to acute or chronic releases to the atmosphere and from underground waste repositories. This article describes the most important aspects to consider in forest model development. It intends to give an overview of the modelling approaches available and to provide guidance on how to address the quantification of radionuclide transport in forests. Furthermore, the most important gaps in modelling the radionuclide cycle in forests are discussed and suggestions are presented to address the variability of forest sites.

MDM2 and HIF1alpha expression levels in different histologic subtypes of malignant pleural mesothelioma: correlation with pathological and clinical data

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis and limited treatment options. Sarcomatoid/biphasic mesotheliomas are characterized by more aggressive behaviour and a poorer prognosis compared with the epithelioid subtype. To date prognostic and tailored therapeutic biomarkers are lacking. The present study analyzed the expression levels of MDM2 and HIF1alpha in different histologic subtypes from chemonaive MPM patients. Diagnostic biopsies of MPM patients from four Italian cancer centers were centrally collected and analyzed. MDM2 and HIF1alpha expression levels were investigated through immunohistochemistry and RT-qPCR. Pathological assessment of necrosis, inflammation and proliferation index was also performed. Molecular markers, pathological features and clinical characteristics were correlated to overall survival (OS) and progression free survival (PFS). Sixty MPM patients were included in the study (32 epithelioid and 28 non-epithelioid). Higher levels of MDM2 (p < 0.001), HIF1alpha (p = 0.013), necrosis (p = 0.013) and proliferation index (p < 0.001) were seen mainly in sarcomatoid/biphasic subtypes. Higher levels of inflammation were significantly associated with epithelioid subtype (p = 0.044). MDM2 expression levels were correlated with HIF1alpha levels (p = 0.0001), necrosis (p = 0.008) and proliferation index (p = 0.009). Univariate analysis showed a significant correlation of non-epithelioid histology (p = 0.04), high levels of necrosis (p = 0.037) and proliferation index (p = 0.0002) with shorter PFS. Sarcomatoid/biphasic and epithelioid mesotheliomas showed different MDM2 and HIF1alpha expression levels and were characterized by different levels of necrosis, proliferation and inflammation. Further studies are warranted to confirm a prognostic and predictive role of such markers and features.

Critical review about MDM2 in cancer: Possible role in malignant mesothelioma and implications for treatment

The tumor suppressor p53 regulates genes involved in DNA repair, metabolism, cell cycle arrest, apoptosis and senescence. p53 is mutated in about 50% of the human cancers, while in tumors with wild-type p53 gene, the protein function may be lost because of overexpression of Murine Double Minute 2 (MDM2). MDM2 targets p53 for ubiquitylation and proteasomal degradation. p53 reactivation through MDM2 inhibitors seems to be a promising strategy to sensitize p53 wild-type cancer cells to apoptosis. Moreover, additional p53-independent molecular functions of MDM2, such as neoangiogenesis promotion, have been suggested. Thus, MDM2 might be a target for anticancer treatment because of its antiapoptotic and proangiogenetic role. Malignant pleural mesothelioma (MPM) is an aggressive asbestos-related tumor where wild-type p53 might be present. The present review gives a complete landscape about the role of MDM2 in cancer pathogenesis, prognosis and treatment, with particular focus on Malignant Pleural Mesothelioma.

Epirubicin plus paclitaxel regimen as second-line treatment of patients with small-cell lung cancer

BACKGROUND/AIM

Most patients with small cell lung cancer (SCLC) experience relapse within one year after first-line treatment. The aim of this study was to describe activity and safety of second-line with epirubicin at 70 mg/m(2) followed by paclitaxel at 135 mg/m(2) on day 1 every three weeks for a maximum of six cycles.

PATIENTS AND METHODS

This is a retrospective review of all patients with SCLC evaluated for second-line treatment between 2003 and 2013 at our Institution.

RESULTS

Sixty-eight patients received the study regimen of epirubicin with paclitaxel. We observed partial response in 19 (30%), stable disease in 22 (34%) and total early failure rate in 23 (36%) patients. Median progression free and overall survival were 21.8 and 26.5 weeks, respectively. Haematological toxicities were as follows: grade 3-4 leukopenia and neutropenia in 18 (31%) and 30 (22%) of patients, respectively; grade 3 anaemia and grade 4 thrombocytopenia were reported in 2 (3%) and 5 (9%) of patients, respectively.

CONCLUSION

Epirubicin with paclitaxel is an active and tolerable second-line regimen in patients with SCLC.

[Psychosocial vulnerability and substance use screening during pregnancy: Evaluation of a composite auto-questionnaire versus usual medical questioning]

AIM

To evaluate auto-questionnaire use for psychosocial vulnerability and substance use (smoking, alcohol consumption, depression, intimate violence) screening during pregnancy versus usual medical report.

MATERIAL AND METHODS

An auto-questionnaire based on validated tests (Fagerström/HSI, T-ACE, EPDS, SSQ6) was proposed to 1977 pregnant patients at their first obstetrical consultation. We compared results of auto-questionnaire and usual medical questioning.

RESULTS

The auto-questionnaire was filled by 1676 pregnant patients (89.4 %). The two Fagerström/HIS questions showed that 20.7 % smoked during pregnancy. T-ACE score was better than usual medical questioning to detect excessive alcohol consumption (4.0 % vs 0.1 %, P<0.05). Drug use before pregnancy was reported by 9.8 % patients in auto-questionnaire, but was only found in 4.9 % of medical files (P<0.001). Seven percent patients reported at least 3 depressive symptoms on 4 purposed in auto-questionnaire. Intimate violence, physical or psychological, was reported in 9.4 %. All of these vulnerability factors were linked together, in auto-questionnaire or in usual medical reports.

CONCLUSION

Using auto-questionnaire based on standardized screening tests could help medical practioneers to detect psychosocial vulnerability and/or substance use during pregnancy.

A fast and simple approach for the estimation of a radiological source from localised measurements after the explosion of a radiological dispersal device

After an explosion of a radiological dispersal device, decision-makers need to implement countermeasures as soon as possible to minimise the radiation-induced risks to the population. In this work, the authors present a tool, which can help providing information about the approximate size of source term and radioactive contamination based on a Gaussian Plume model with the use of available measurements for liquid or aerosolised radioactivity. For two-field tests, the source term and spatial distribution of deposited radioactivity are estimated. A sensitivity analysis of the dependence on deposition velocity is carried out. In case of weak winds, a diffusive process along the wind direction is retained in the model.

Effects of sulfonylureas on tumor growth: a review of the literature

Type 2 diabetes mellitus patients are at higher cancer risk, probably because of hyperinsulinemia and insulin growth factor 1 pathway activation. The effects of antidiabetic drugs on cancer risk have been described and discussed in several studies suggesting opposite effects of the biguanide metformin and sulfonylureas on cancer incidence and mortality. The anticancer mechanisms of metformin have been clarified, and some clinical studies, particularly in breast cancer patients, have been published or are currently ongoing; however, data about the effects of sulfonylureas on cancer growth are less consistent. The aims of this work are to review preclinical evidence of second-generation sulfonylureas effects on tumor growth, to clarify the potential mechanisms of action, and to identify possible metabolic targets for patient selection. Most evidence is on the adenosine triphosphate-sensitive potassium channels inhibitor glibenclamide, which interacts with reactive oxygen species production thus inducing cancer cell death. Among diarylsulfonylureas, next-generation DW2282 derivatives are particularly promising because of the proapoptotic activity in multidrug-resistant cells.

Modeling of the fate of radionuclides in urban sewer systems after contamination due to nuclear or radiological incidents

After an accidental radioactive contamination by aerosols in inhabited areas, the radiation exposure to man is determined by complex interactions between different factors such as dry or wet deposition, different types of ground surfaces, chemical properties of the radionuclides involved and building development as well as dependence on bomb construction e.g. design and geometry. At short-term, the first rainfall is an important way of natural decontamination: deposited radionuclides are washed off from surfaces and in urban areas the resulting contaminated runoff enters the sewer system and is collected in a sewage plant. Up to now the potential exposure caused by this process has received little attention and is estimated here with simulation models. The commercial rainfall-runoff model for urban sewer systems KANAL++ has been extended to include transport of radionuclides from surfaces through the drainage to various discharge facilities. The flow from surfaces is modeled by unit hydrographs, which produce boundary conditions for a system of 1d coupled flow and transport equations in a tube system. Initial conditions are provided by a map of surface contamination which is produced by geo-statistical interpolation of γ-dose rate measurements taking into account the detector environment. The corresponding methodology is implemented in the Inhabited Area Monitoring Module (IAMM) software module as part of the European decision system JRODOS. A hypothetical scenario is considered where a Radiation Dispersal Device (RDD) with Cs-137 is detonated in a small inhabited area whose drainage system is realistically modeled. The transition of deposited radionuclides due to rainfall into the surface runoff is accounted for by different nuclide-specific entrainment coefficients for paved and unpaved surfaces. The concentration of Cs-137 in water is calculated at the nodes of the drainage system and at the sewage treatment plant. The external exposure to staff of the treatment plant is estimated. For Cs-137 radiation levels in the plant are low since wash-off of cesium from surfaces is an ineffective process.

Serum osteoprotegerin correlates with age and bone mass in postmenopausal, but not in fertile age women

PURPOSE OF INVESTIGATION

Osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) are bone turnover modulators expressed by osteoblasts. The aim of this study was to assess the relationship between the circulating OPG/RANKL system, age and bone mass, in fertile age and postmenopausal women.

METHODS

In this cross-sectional observational study on 48 patients (fertile age, n = 22; postmenopause, n = 26), we investigated the correlation between serum OPG and RANKL, age and bone mineral density (BMD). Serum concentrations of OPG and RANKL were determined by enzyme-linked immunosorbent assay (ELISA); estimate BMD evaluation was performed with heel quantitative ultrasonometry (QUS).

RESULTS

Serum OPG significantly increased (p = 0.003) and serum RANKL significantly decreased (p = 0.002), in the postmenopausal group compared to fertile age women. A significant correlation of serum OPG with age (r(s) = 0.39, p = 0.047) and BMD (r(s) = 0.45, p = 0.023) in postmenopausal women, and between RANKL and BMD (r(s) = 0.48, p = 0.024) in fertile age was found.

CONCLUSION

These data demonstrate in vivo that the OPG/RANKL system is significantly associated with menopausal status and could play a role in postmenopausal osteoporosis.

Sublethal concentrations of the platinum(II) complex [Pt(O,O'-acac)(gamma-acac)(DMS)] alter the motility and induce anoikis in MCF-7 cells

BACKGROUND AND PURPOSE

We showed previously that a new Pt(II) complex ([Pt(O,O'-acac)(gamma-acac)(DMS)]) exerted high and fast apoptotic processes in MCF-7 cells. The objective of this study was to investigate the hypothesis that [Pt(O,O'-acac)(gamma-acac)(DMS)] is also able to exert anoikis and alter the migration ability of MCF-7 cells, and to show some of the signalling events leading to these alterations.

EXPERIMENTAL APPROACH

Cells were treated with sublethal doses of [Pt(O,O'-acac)(gamma-acac)(DMS)], and the efficiency of colony initiation and anchorage-independent growth was assayed; cell migration was examined by in vitro culture wounding assay. Gelatin zymography for MMP-2 and -9 activities, Western blottings of MMPs, MAPKs, Src, PKC-epsilon and FAK, after [Pt(O,O'-acac)(gamma-acac)(DMS)] treatment, were also performed.

KEY RESULTS

Sub-cytotoxic drug concentrations decreased the: (i) anchorage-dependent and -independent growth; (ii) migration ability; and (iii) expression and activity of MMP-2 and MMP-9. [Pt(O,O'-acac)(gamma-acac)(DMS)] provoked the generation of reactive oxygen species (ROS), and the activation of p38MAPK, Src and PKC-epsilon. p38MAPK phosphorylation, cell anoikis and migration due to [Pt(O,O'-acac)(gamma-acac)(DMS)] were blocked by PKC-epsilon inhibition. Furthermore, Src inhibition blocked the [Pt(O,O'-acac)(gamma-acac)(DMS)]-provoked activation of PKC-epsilon, while ROS generation blockage inhibited the activation of Src, and also the decrement of phosphorylated FAK observed in detached [Pt(O,O'-acac)(gamma-acac)(DMS)]-treated cells.

CONCLUSIONS AND IMPLICATIONS

Sublethal concentrations of [Pt(O,O'-acac)(gamma-acac)(DMS)] induced anoikis and prevented events leading to metastasis via alterations in cell migration, anchorage independency, stromal interactions and MMP activity. Hence, [Pt(O,O'-acac)(gamma-acac)(DMS)] may be a promising therapeutic agent for preventing growth and metastasis of breast cancer.

miR-212 increases tumor necrosis factor-related apoptosis-inducing ligand sensitivity in non-small cell lung cancer by targeting the antiapoptotic protein PED

PED/PEA-15 (PED) is a death effector domain family member of 15 kDa with a broad antiapoptotic function found overexpressed in a number of different human tumors, including lung cancer. To date, the mechanisms that regulate PED expression are unknown. Therefore, we address this point by the identification of microRNAs that in non-small cell lung cancer (NSCLC) modulate PED levels. In this work, we identify miR-212 as a negative regulator of PED expression. We also show that ectopic expression of this miR increases tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced cell death in NSCLC cells. In contrast, inhibition of endogenous miR-212 by use of antago-miR results in increase of PED protein expression and resistance to TRAIL treatment. Besides, in NSCLC, we show both in vitro and in vivo that PED and miR-212 expressions are inversely correlated, that is, PED is upregulated and miR-212 is rarely expressed. In conclusion, these findings suggest that miR-212 should be considered as a tumor suppressor because it negatively regulates the antiapoptotic protein PED and regulates TRAIL sensitivity.

Effects of cisplatin on matrix metalloproteinase-2 in transformed thyroid cells

We investigated the effects of cisplatin (cisPt) on matrix metalloproteinase-2 (MMP-2) gelatinolitic activity in transformed PC E1Araf rat thyroid cells. Cells incubated with increasing cisPt concentrations showed dose- and time-dependent decrease of the MMP-2 protein and activity. CisPt provoked the translocation from the cytosol to the plasma membrane of atypical protein kinase C-zeta (PKC-zeta) and the activation of PKB/AKT. The effect of cisPt on MMP-2 was dependent on PKC-zeta activation since it was potentiated by a myristoylated PKC-zeta pseudo substrate peptide or by PKC-zeta down-regulation by siRNA. Moreover, MMP-2 activity modulation by cisPt was also dependent on PKB/AKT activation since it was decreased by PKB/AKT down-regulation by siRNA or by pharmacological inhibition of PI3K, thus indicating the importance of the balance of PKB/AKT and PKC-zeta in regulating the cisPt effect on MMP-2 activity. The PC E1Araf cells displayed a migratory capacity that was blocked by MMP-2 down-regulation using siRNA or pharmacological inhibition. The inhibition of cell migration was also obtained with cisPt; in cisPt-treated cells the administration of MMP-2 active protein was able to restore cell migration capacity. In conclusion, the decrease of MMP-2 secretion after cisPt was allowed by PKB/AKT and counteracted by PKC-zeta; the cisPt-provoked inhibition of MMP-2 secretion ended in reduction of cell migration.

Cisplatin reduces endothelial cell migration via regulation of type 2-matrix metalloproteinase activity

AIMS

In this study we investigated the effect of cisplatin on endothelial cell migration, an essential process for vascular remodeling and regeneration in several physiological and pathological situations.

MATERIAL AND METHODS

Human umbilical vein endothelial cells (HUVEC) were treated with cisplatin and endothelial cell migration analyzed by fluorescence and scratch-wound migration assay. MMP2 and MMP9 activity were determined by zymographic assay, and MAPK activation by Western blotting analysis.

RESULTS

We demonstrated that cisplatin provoked a time- and dose-dependent decrease of HUVEC migration; this effect was clearly independent from its well known cytotoxic activity. In addition, cisplatin markedly reduced MMP2 activity in both conditioned media and cell lysates, increased p38 MAPK and JNK phosphorylation, but did not affect ERK phosphorylation. Endothelial cell migration was attenuated by treatment of cells with GM6001, a non-specific inhibitor of MMPs, or by a selective anti-MMP2 antibody. However, treatment of cells with SB202190 or SP600125, inhibitors of p38 MAPK and JNK respectively, did not affect HUVEC migration.

CONCLUSION

These results suggested that cisplatin induced a reduction of endothelial cell migration through an inhibition of MMP2 activity by downstream signal transduction pathways independent of JNK and p38 MAPK activation.

Anti-apoptotic effects of protein kinase C-delta and c-fos in cisplatin-treated thyroid cells

BACKGROUND AND PURPOSE

We showed previously that cisplatin inititates a signalling pathway mediated by PKC-delta/extracellular signal-regulated kinase (ERK), important for maintaining viability in PC Cl3 thyroid cells. The studies described herein examined whether c-fos was associated with cisplatin resistance and the signalling link between c-fos and PKC-delta/ERK.

EXPERIMENTAL APPROACH

Cells were treated with various pharmacological inhibitors of PKCs and ERK, or were depleted of c-fos, PKC-delta, PKC-epsilon and caspase-3 by small interfering RNA (siRNA), then incubated with cisplatin and cytotoxicity assessed.

KEY RESULTS

Cisplatin provokes the induction of c-fos and the activation of conventional PKC-beta, and novel PKC-delta and -epsilon. The cisplatin-provoked c-fos induction was decreased by Gö6976, a PKC-beta inhibitor; by siRNA for PKC-delta- but not that for PKC-epsilon or by PD98059, a mitogen-activated protein kinase/ERK kinase inhibitor. Expression of c-fos was abolished by GF109203X, an inhibitor of all PKC isoforms, or by PD98059 plus Gö6976 or by PKC-delta-siRNA plus Gö6976. When c-fos expression was blocked by siRNA, cisplatin cytotoxicity was strongly enhanced with increased caspase-3 activation. In PKC-delta-depleted cells treated with cisplatin, caspase-3 activation was increased and cell viability decreased. In these PKC-delta-depleted cells, PD98059 did not affect caspase-3 activation.

CONCLUSIONS AND IMPLICATIONS

In PC Cl3 cells, in the cell signalling pathways that lead to cisplatin resistance, PKC-delta controls ERK activity and, together with PKC-beta, also the induction of c-fos. Hence, the protective role of c-fos in thyroid cells has the potential to provide new opportunities for therapeutic intervention.

Angiotensin II induces MMP 2 activity via FAK/JNK pathway in human endothelial cells

Matrix metalloproteinases (MMPs) play an important role in the pathogenesis of cardiovascular diseases and are modified in response to a variety of stimuli such as bioactive peptides, cytokines and/or grown factors. In this study, we demonstrated that angiotensin II (Ang II) induces a time- and dose-dependent increase in the activity of metalloproteinase 2 (MMP 2) in human umbilical vein endothelial cells (HUVEC). The effect of Ang II was markedly attenuated in cells pretreated with wortmannin and LY294002, two selective inhibitors of phosphatidylinositol-3-kinase (PI3K), indicating that PI3K plays a key role in regulating MMP 2 activity. Similar results were observed when HUVEC were pretreated with genistein, a non-selective tyrosine kinases inhibitor, or with the specific Src-family tyrosine kinase inhibitor PP2, demonstrating the involvement of protein tyrosine kinases, and particularly Src-family tyrosine kinases on the downstream signaling pathway of Ang II receptors. Furthermore, Ang II-induced MMP 2 activation was markedly blocked by SP600125, a selective c-Jun N-terminal kinase (JNK) inhibitor, or pre-treatment of cells with antisense oligonucleotide to focal adhesion kinase (FAK), indicating that both molecules were important for the activation of MMP 2 by Ang II receptor stimulation. In conclusion, these results suggest that Ang II mediates an increase in MMP 2 activity in macrovascular endothelial cells through signal transduction pathways dependent on PI3K and Src-family tyrosine kinases activation, as well as JNK and FAK phosphorylation.

PKC-epsilon-dependent cytosol-to-membrane translocation of pendrin in rat thyroid PC Cl3 cells

We studied the expression and the hormonal regulation of the PDS gene product, pendrin, which is, in thyrocytes, responsible for the iodide transport out of the cell. We show that PC Cl3 cells, a fully differentiated thyroid cell line, grown without TSH and insulin, express very low level of PDS mRNA; such expression is greatly increased after stimulation with insulin or TSH. (125)I pre-loaded cells showed an (125)I efflux accelerated in chloride-containing buffer with respect to chloride-free buffer, suggesting that this efflux is chloride dependent. By immunoblotting, pendrin was found in agonists-stimulated cells, whereas it was barely detectable in un-stimulated cells. An increase in both PDS mRNA and protein was also obtained using phorbol ester PMA, or using 8-Br-cAMP and forskolin. Stimulation with insulin (1 microg/ml; 0-40 min) provoked the cytosol-to-membrane translocation of pendrin and a decrease of intracellular I(-) content in (125)I pre-loaded cells. Insulin- or PMA-treated cells also showed a cytosol-to-membrane translocation of PKC-delta and -epsilon. Inhibition of both PKC-delta and -epsilon activities by GF109203X blocked pendrin translocation, whilst the inhibition of PKA did not. The selective inhibition of PKC-delta by rottlerin did not affect the insulin-provoked translocation of pendrin whilst it was inhibited by a PKC-epsilon translocation inhibitor peptide and also by PKC-epsilon downregulation using the small interfering RNA, thus indicating that such translocation was due to PKC-epsilon activity. In conclusion, our study demonstrates that, in PC Cl3 cells, pendrin expression and localisation are regulated by insulin and influenced by a PKC-epsilon-dependent intracellular pathway.