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Es gibt 6 Arten länglicher Mineralpartikel (EMP), die bestimmten dimensionalen und morphologischen Kriterien entsprechen und als Asbest bekannt sind. Da Asbest für Gesundheitsprobleme wie die Asbestose und das maligne Mesotheliom verantwortlich ist, wurde er gut erforscht. Trotzdem kommt es weltweit weiterhin zu einer erheblichen Exposition, die möglicherweise 125 Millionen Menschen am Arbeitsplatz betrifft und jährlich Tausende von Todesfällen durch Exposition in Haushalten verursacht. Es gibt jedoch andere EMP, wie z.B. faserigen/asbestiformen Erionit, die als Karzinogene eingestuft sind und in Gebieten, in denen sie in lokale Baumaterialien eingebaut oder durch Erdbewegungen in die Umwelt freigesetzt wurden, mit Krebs in Verbindung gebracht wurden. Erionit ist ein stärkeres Karzinogen als Asbest, da es aber selten für kommerzielle Zwecke verwendet wird, wurden die Expositionswege weniger gut untersucht. Trotz der offensichtlichen Ähnlichkeiten zwischen Asbest und faserigem Erionit unterscheiden sich ihre Gesundheitsrisiken und Expositionspfade erheblich. Dieser Artikel untersucht die Gefahren, die von EMP ausgehen, mit besonderem Schwerpunkt auf Erionitfasern. Er umfasst eine Diskussion der globalen Standorte von Erionit und ähnlichen gefährlichen Mineralien, einen Vergleich der vielfältigen Expositionspfade für Asbest und faserigen Erionit, eine kurze Diskussion der verwirrenden Nomenklatur im Zusammenhang mit EMP und Überlegungen zur Zunahme globaler Mesotheliomfälle.

Malignant mesothelioma (MM) is an incurable cancer of the serosal lining that is often caused by exposure to asbestos. Therefore, novel agents for the prevention and treatment of this disease are urgently needed. Asbestos induces the release of pro-inflammatory cytokines such as IL-1β and IL-6, which play a role in MM development. IL-6 is a component of the JAK-STAT3 pathway that contributes to inflammation-associated tumorigenesis. Glycoprotein 130 (gp130), the signal transducer of this signaling axis, is an attractive drug target because of its role in promoting neoplasia via the activation of downstream STAT3 signaling. The anticancer drug, SC144, inhibits the interaction of gp130 with the IL-6 receptor (IL6R), effectively blunting signaling from this inflammatory axis. To test whether the inflammation-related release of IL-6 plays a role in the formation of MM, we evaluated the ability of SC144 to inhibit asbestos-induced carcinogenesis in a mouse model. The ability of sulindac and anakinra, an IL6R antagonist/positive control, to inhibit MM formation in this model was tested in parallel. Asbestos-exposed Nf2+/−;Cdkn2a+/− mice treated with SC144, sulindac or anakinra showed significantly prolonged survival compared to asbestos-exposed vehicle-treated mice. STAT3 activity was markedly decreased in MM specimens from SC144-treated mice. Furthermore, SC144 inhibited STAT3 activation by IL-6 in cultured normal mesothelial cells, and in vitro treatment of MM cells with SC144 markedly decreased the expression of STAT3 target genes. The emerging availability of newer, more potent SC144 analogs showing improved pharmacokinetic properties holds promise for future trials, benefitting individuals at high risk of this disease.

PDF file - 425K, Supplementary Figure 2. Blockade of TNF-α-induced NF-κB signaling by bortezomib and IKKβ inhibitor.

Supplementary Table 1 and 2 - PDF file 42K, Supplemental Table 1. Phospho-mTOR and Rictor immunoreactivity in CCCs and SACs. Supplemental Table 2. Effects of AZD8055 or RAD001 on cell cycle progression

PDF file - 196K, Immunoblot analysis of P-PAK1/2/3, total PAK1/2/3, P-AKT, AKT, P-ERK1/2, ERK1/2 and beta actin levels 24-hr post-nucleofection of pcDNA or pcDNA-PID in Me12 cells (left panels); pcDNA and increasing concentrations of pcDNA-PID in Meso 22 cells (right panels)

S2. ASXL structure and evolution

Conflict of Interest Form from Inflammation-Related IL1β/IL1R Signaling Promotes the Development of Asbestos-Induced Malignant Mesothelioma

PDF file - 32K, IHC analysis of murine MM tissues with the P-PAK1,2,3 (Ser 141) antibody with and without pre-treatment with lambda phosphatase (lamdaPPtase)

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Supplementary Figure 1 - PDF file 46K, Establishment of RAD001-resistant variant cell lines

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Top, Scatter plot showing difference in MM incidence between asbestos-exposed wild-type (WT, Asc +/+), Asc+/-, and Asc-/- mice. Bottom, summary showing statistically significant difference in MM incidence between WT mice and Asc-/- mice (p < 0.05), but not between WT and Asc+/- mice.

Advanced renal cell carcinoma (RCC) is an invariably fatal cancer. Currently, small-molecule inhibitors that target cell growth, angiogenesis, or nutrient-sensing pathways represent the primary pharmacologic interventions for this disease, but these inhibitors only delay tumor progression and are not curative. The cytokine IFN-γ showed the potential to provide lasting remission in several phase I/II trials for advanced RCCs, but subsequent trials, including a multicenter phase III study using IFN-γ as a monotherapy for RCCs, were less promising. Notably, these trials were designed to exploit the indirect immunomodulatory effects of IFN-γ, whereas its direct antitumor properties—including its ability to trigger programmed cell death in tumors—remain mostly untapped. Here, we show that the proteasome inhibitor bortezomib (PS-341, Velcade) sensitizes otherwise resistant RCC cells to direct necrotic death by IFN-γ. Mechanistically, we show that bortezomib functions, at least in part, by inhibiting prosurvival NF-κB signaling. In the absence of this signal, IFN-γ triggers programmed necrosis (or “necroptosis”) dependent on the kinase RIP1. When taken together with the observation that NF-κB signaling is elevated in RCCs, these results provide rationale for the combined use of IFN-γ and bortezomib in the treatment of metastatic RCCs. Mol Cancer Ther; 12(8); 1568–78. ©2013 AACR.

Supplementary Data from Inactivation of p21-Activated Kinase 2 (Pak2) Inhibits the Development of Nf2-Deficient Tumors by Restricting Downstream Hedgehog and Wnt Signaling

PDF file - 27K, Expression of PID inhibits PAK phosphorylation, cell viability (MTS assay) and G418-resistant colony formation in Meso-17 cells

The goal of this study was to examine the role of mTOR complex 2 (mTORC2) as a therapeutic target in ovarian clear cell carcinoma (CCC), which is regarded as an aggressive, chemoresistant histologic subtype. Using tissue microarrays of 98 primary ovarian cancers [52 CCCs and 46 serous adenocarcinomas (SAC)], activation of mTORC2 was assessed by immunohistochemistry. Then, the growth-inhibitory effect of mTORC2-targeting therapy, as well as the role of mTORC2 signaling as a mechanism for acquired resistance to the mTOR complex 1 (mTORC1) inhibitor RAD001 in ovarian CCC, were examined using two pairs of RAD001-sensitive parental (RMG2 and HAC2) and RAD001-resistant CCC cell lines (RMG2-RR and HAC2-RR). mTORC2 was more frequently activated in CCCs than in SACs (71.2% vs. 45.7%). Simultaneous inhibition of mTORC1 and mTORC2 by AZD8055 markedly inhibited the proliferation of both RAD001-sensitive and -resistant cells in vitro. Treatment with RAD001 induced mTORC2-mediated AKT activation in RAD001-sensitive CCC cells. Moreover, increased activation of mTORC2–AKT signaling was observed in RAD001-resistant CCC cells compared with the respective parental cells. Inhibition of mTORC2 during RAD001 treatment enhanced the antitumor effect of RAD001 and prevented CCC cells from acquiring resistance to RAD001. In conclusion, mTORC2 is frequently activated, and can be a promising therapeutic target, in ovarian CCCs. Moreover, mTORC2-targeted therapy may be efficacious in a first-line setting as well as for second-line treatment of recurrent disease developing after RAD001-treatment. Mol Cancer Ther; 12(7); 1367–77. ©2013 AACR.

PDF file - 187K, Immunoblot analysis of MM cells (Me12) treated with siRNA against PAK1 and PAK2 revealing that the slower migrating band is PAK1 and the faster migrating band is PAK2

Supplemental Figures S1-S4 + two supp. tables

Exposure to asbestos is causally associated with the development of malignant mesothelioma, a cancer of cells lining the internal body cavities. Malignant mesothelioma is an aggressive cancer resistant to all current therapies. Once inhaled or ingested, asbestos causes inflammation in and around tissues that come in contact with these carcinogenic fibers. Recent studies suggest that inflammation is a major contributing factor in the development of many types of cancer, including malignant mesothelioma. The NALP3/NLRP3 inflammasome, including the component ASC, is thought to be an important mediator of inflammation in cells that sense extracellular insults, such as asbestos, and activate a signaling cascade resulting in release of mature IL1β and recruitment of inflammatory cells. To determine if inflammasome-mediated inflammation contributes to asbestos-induced malignant mesothelioma, we chronically exposed Asc-deficient mice and wild-type littermates to asbestos and evaluated differences in tumor incidence and latency. The Asc-deficient mice showed significantly delayed tumor onset and reduced malignant mesothelioma incidence compared with wild-type animals. We also tested whether inflammation-related release of IL1β contributes to tumor development in an accelerated mouse model of asbestos-induced malignant mesothelioma. Nf2+/−;Cdkn2a+/− mice exposed to asbestos in the presence of anakinra, an IL1 receptor (IL1R) antagonist, showed a marked delay in the median time of malignant mesothelioma onset compared with similarly exposed mice given vehicle control (33.1 weeks vs. 22.6 weeks, respectively). Collectively, these studies provide evidence for a link between inflammation-related IL1β/IL1R signaling and the development of asbestos-induced malignant mesothelioma. Furthermore, these findings provide rationale for chemoprevention strategies targeting IL1β/IL1R signaling in high-risk, asbestos-exposed populations. Cancer Prev Res; 9(5); 406–14. ©2016 AACR.

PDF file - 5653K, Supplementary Figure 1. Genomic copy number analysis of HRC cell lines.

PDF file - 48K, 2-dimensional immunoblot analysis of PAK1, PAK1/2/3 and P PAK1/2/3 levels in four different human MM cell lines

Expression of RIPK3 induced activation of MLKL and cell death, which was rescued by treatment with GSK'872. Transduction of M12 cells (C) and M22 cells (D) with lentivirus expressing shMLKL or shGFP and then selected for 72 h with puromycin. Stable cells expressing shMLKL or shGFP were then infected with WPI or WPI expressing RIPK3. Immunoblotting and cell viability were performed after 48 h to detect the activation of MLKL. Expression of RIPK3 induced necroptosis, which was rescued by MLKL knockdown.

Analysis of The Cancer Genome Atlas (TCGA) mesothelioma cases.

Assay IDs for quantitative RT-PCR analysis to validate genes differentially expressed between malignant mesotheliomas (MMs) derived from triple-CKO mice versus those from double-CKO mice.

Drug sensitivity differences between 12 RIPK3-negative and 3 RIPK3-positive human MM cell lines as assessed by MTS assay. Treatment of MM cell lines with three different doses of doxorubicin. First three bars in each bar graph represent viability of RIPK3-positive (+) MM cell lines, M49, M29 and M217, respectively. The bars shown to the right in each graph represent the viability of each of the 12 RIPK3-negative (-) MM lines. All drug treatments were for 72 h.

Re-expression of RIPK3 expression triggers necroptosis in RIPK3-negative MM cell lines, and RIPK3 inhibition rescues the cell death caused by necroptosis. A, RIPK3-negative MM cell lines M12 and M22 were transduced with WPI lentivirus expressing RIPK3 WT or empty vector and treated with the apoptosis inhibitor zVAD and/or the RIPK3 inhibitor GSK'872 for 1-4 d. Results of immunoblot analysis (24 h) and clonogenic assay (4 d) are shown. B, Cell viability determined with hemocytometer and trypan blue dye exclusion test.

Efficiency of infection of MM cell lines infected with a pWPI lentivirus that expresses GFP marker alone (pWPI, control) or with a pWPI lentivirus that expresses both GFP and either RIPK3 WT or RIPK3-KD. Representative images indicate efficiency of infection of RIPK3-negative MM cell lines M12 and MSTO211H. Photographs of GFP fluorescence and combined GFP plus brightfield were taken 24 h after the initiation of infection. Note that most cells infected with pWPI-RIPK3 WT were floating, dead cells.

Characterization of malignant mesothelioma (MM) from Bap1f/f mouse, which was detected 45 weeks after intrathoracic injection of Adeno-Cre virus. A, Immunoblot confirming loss of Bap1 expression in MM from Bap1 conditional knockout mouse 526, with tumor also showing greatly reduced expression of Nf2 and p16Ink4a as well as Akt activation when compared to normal mesothelial cells (NMC). B, Immunoblots of same lysates as in panel A showing Bap1-related loss of deubiquitination activity in MM 526, as indicated by presence of Ub-H2A in tumor but not in NMC, along with overexpression of product of PRC2 target gene Aldh1a2. In addition to acquired loss of Nf2 expression (panel A), MM 526 shows loss of p-Yap activity, indicative of aberrant Hippo signaling. C, Demonstration that loss of expression of Nf2 and p16Ink4a is acquired, not due to excision of floxed Nf2 and Cdkn2a alleles. Control WT and control Î"/Î" lanes depict sizes of wild type and homozygously floxed (Î"/Î") Bap1, Nf2, and Cdkn2a alleles. DNA from Bap1Î"/Î" mouse tail and matching MM from animal 526 verify that Bap1, but not Nf2 or Cdkn2a, has floxed alleles. Note that the primers used to detect mutant Bap1 allele were designed to bind outside the flox sites, such that a smaller band is seen when Cre recombinase excises Bap1 exon 7.

Lentivirus plasmids expressing shMLKL.

100 of the top gene sets differentially affected (FDR < 0.25) in MMs from triple-CKOa versus those from double-CKO mice by using GSEA applied to MSigDB gene sets.

Differences in survival of mice succumbing to malignant mesothelioma after IT injection with Adeno-Cre in different conditional knockout mouse groups.

Human malignant mesothelioma (MM) cell lines frequently show down regulated expression of RIPK3 protein. Western blotting illustrating RIPK3 protein expression in 20 human MM cell lines. Normal mesothelial cell line NM311A was used as a control.

Purpose: Akt plays a central role in regulating tumor cell survival and cell cycle progression and is regarded as a promising therapeutic target. We used genetically defined mouse models that develop spontaneous tumors exhibiting activated Akt to determine if Akt inhibition by GSK690693 is effective in the treatment of cancer. The broad long-term objective of this project was to use preclinical cancer models with precisely defined genetic lesions to elucidate the efficacy of targeting Akt with GSK690693.Experimental Design: We tested the in vivo effects of GSK690693 in Lck-MyrAkt2 transgenic mice that develop lymphomas, heterozygous Pten+/− knockout mice that exhibit endometrial tumors, and TgMISIIR-TAg-DR26 mice that develop ovarian carcinomas, all of which exhibit hyperactivation of Akt. In addition to standard disease onset and histology, tumors arising in treated animals were examined by immunohistochemistry to verify downregulated Akt signaling relative to placebo-treated mice. When possible, drug response was evaluated in tumor cell cultures by standard proliferation and apoptosis assays and by immunoblotting with various phosphospecific antibodies.Results: GSK690693 exhibited efficacy irrespective of the mechanism of Akt activation involved. Interestingly, GSK690693 was most effective in delaying tumor progression in Lck-MyrAkt2 mice expressing a membrane-bound, constitutively active form of Akt. Both tumors and primary cell cultures displayed downregulation of the Akt pathway, increased apoptosis, and primarily decreased cell proliferation.Conclusion: These results suggest that GSK690693 or other Akt inhibitors might have therapeutic efficacy in human cancers with hyperactivated Akt and/or a dependence on Akt signaling for tumor progression. Clin Cancer Res; 16(2); 486–96

Re-expression of RIPK3 induces necrosis of RIPK3-negative MM cells. M8, M12, M17 and MSTO211H cells were transduced with control WPI lentivirus or WPI lentivirus expressing RIPK3 cDNA for 24 hours before seeding in 96-well plates and assaying for cell viability (MTS assay) and release of LDH, an indicator of necrosis. Cells were assayed 48 hours post-seeding.

DNA methyltransferase DNMT1 suppresses RIPK3 transcription. A, Immunoblot analysis of MM cells with knockdown of DNMT1 protein (184 kDa) expression. RIPK3-negative cells were transfected with two siRNAs against DNMT1 or an siControl (siCon), and DNMT1 protein levels were determined by immunoblot analysis 72 hours post-transfection. B, Semi-quantitative RT-PCR to detect knockdown of DNMT1 (500 bp), re-expression of RIPK3 (700 bp), as well as expression of control GAPDH (800 kDa).