Influence of MMR, MGMT Promotor Methylation and Protein Expression on Overall and Progression-Free Survival in Primary Glioblastoma Patients Treated with Temozolomide.

Glioblastoma is the most common malignant brain tumor in adults. Standard treatment includes tumor resection, radio-chemotherapy and adjuvant chemotherapy with temozolomide (TMZ). TMZ methylates DNA, whereas O6-methylguanine DNA methyltransferase (MGMT) counteracts TMZ effects by removing the intended proteasomal degradation signal. Non-functional MGMT mediates the mismatch repair (MMR) system, leading to apoptosis after futile repair attempts. This study investigated the associations between MGMT promoter methylation, MGMT and MMR protein expression, and their effect on overall survival (OS) and progression-free survival (PFS) in patients with glioblastoma. MGMT promoter methylation was assessed in 42 treatment-naïve patients with glioblastoma WHO grade IV by pyrosequencing. MGMT and MMR protein expression was analyzed using immunohistochemistry. MGMT promoter methylation was present in 52%, whereas patients <70 years of age revealed a significantly longer OS using a log-rank test and a significance threshold of p ≤ 0.05. MGMT protein expression and methylation status showed no correlation. MMR protein expression was present in all patients independent of MGMT status and did not influence OS and PFS. Overall, MGMT promoter methylation implicates an improved OS in patients with glioblastoma aged <70 years. In the elderly, the extent of surgery has an impact on OS rather than the MGMT promoter methylation or protein expression.

Imaging Properties and Tumor Targeting of 68Ga-NeoBOMB1, a Gastrin-Releasing Peptide Receptor Antagonist, in GIST Patients.

Background: Gastrin-releasing peptide receptors (GRPRs) are molecular imaging targets in multiple malignancies. Recently, NeoBOMB1, a 68Ga-labelled antagonist to GRPRs, was developed for PET. Here we report the outcome of a Phase I/IIa clinical trial (EudraCT 2016-002053-38) describing diagnostic properties and covariates influencing uptake of 68Ga-NeoBOMB1 in oligometastatic gastrointestinal stromal tumor (GIST) patients. Methods: Nine patients with advanced GIST using PET/CT (computed tomography) were included. After kit-based 68Ga-NeoBOMB1 preparation with a licensed 68Ge/68Ga generator, 3 MBq/kg body weight were injected intravenously. PET/CT included dynamic and static PET scans 5, 12 and 18 min and 1, 2, and 3−4 h post injection (first six patients) and static PET scans 2 and 3−4 h post injection (last three participants). Tumor targeting was assessed on a per-lesion and per-patient basis. Results: Six patients showed visible radiotracer uptake in at least one tumor lesion. Seventeen out of 37 tumor lesions exhibited significant 68Ga-NeoBOMB1 uptake (median SUVmax 11.8 [range 2.8−51.1] 2 h p.i. and 13.2 [range 2.5−53.8] 3−4 h p.i) and improved lesion-to-background contrast over time. Five lesions (13.5%) were identified only by 68Ga-NeoBOMB1-PET, with no correlation on contrast-enhanced CT. Three patients showed no radiotracer accumulation in any lesions. Tracer uptake correlated with male sex (p < 0.0001), higher body mass index (p = 0.007), and non-necrotic lesion appearance (p = 0.018). There was no association with whole-lesion contrast enhancement, hepatic localization, mutational status, or disease duration. Conclusions: 68Ga-NeoBOMB1-PET exhibits variable tumor uptake in advanced-stage GIST patients, correlating with lesion vitality based on CT contrast uptake, opening the possibility of a theragnostic approach in selected cases.

Molecular Characteristics of Radon Associated Lung Cancer Highlights MET Alterations.

Effective targeted treatment strategies resulted from molecular profiling of lung cancer with distinct prevalent mutation profiles in smokers and non-smokers. Although Rn is the second most important risk factor, data for Rn-dependent driver events are limited. Therefore, a Rn-exposed cohort of lung cancer patients was screened for oncogenic drivers and their survival and genetic profiles were compared with data of the average regional population. Genetic alterations were analysed in 20 Rn-exposed and 22 histologically matched non-Rn exposed LC patients using targeted Next generation sequencing (NGS) and Fluorescence In Situ Hybridization (FISH). Sufficient material and sample quality could be obtained in 14/27 non-exposed versus 17/22 Rn-exposed LC samples. Survival was analysed in comparison to a histologically and stage-matched regional non-exposed lung cancer cohort (n = 51) for hypothesis generating. Median overall survivals were 83.02 months in the Rn-exposed and 38.7 months in the non-exposed lung cancer cohort (p = 0.22). Genetic alterations of both patient cohorts were in high concordance, except for an increase in MET alterations and a decrease in TP53 mutations in the Rn-exposed patients in this small hypothesis generating study.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3.

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Patients with double/triple copy number gains on C-MYC, BCL2, and/or BCL6 treated with standard chemotherapy have a similarly poor prognosis than those with high-grade B cell lymphoma with C-MYC and BCL2 and/or BCL6 rearrangements: a single-center experience on a consecutive cohort of large B cell lymphomas.

High-grade B cell lymphomas with rearrangements on C-MYC and BCL2 and/or BCL6 (HGBL with MYC and BCL2 and/or Bcl6 rearrangement) are associated with worse clinical outcomes and thus were introduced as a separate new category in the recently updated WHO classification. From 2012 to 2016, we analyzed a consecutive cohort of large B cell lymphomas (LBCLs) for C-MYC, BCL2, and BCL6 rearrangements and correlated our results with clinical-pathological parameters. Ten of 78 (13%) cases had a C-MYC and BCL2 and/or BCL6 rearrangement, so-called double or triple hit (DH), while double/triple copy number gains (CNGs) were found in eight (10%) patients. Patients with a high-grade lymphoma with DH or CNG progressed significantly more often after first-line chemotherapy (p = 0.005). When treated with standard chemotherapy, patients with a DH or CNG had a significantly worse overall (OS) and recurrence free survival (RFS) compared with all other patients (p = 0.033 and p < 0.001, respectively). Thus, patients with a diffuse large B cell lymphoma, harboring a double/triple CNG, seem to have a similar poor prognosis than those with a DH. Though our data can only be regarded as preliminary, our results warrant further investigations to fully elucidate the role of CNGs as well as underlying molecular mechanisms resulting in aggressive behavior in LBCL.

Development of bivalent triarylalkene- and cyclofenil-derived dual estrogen receptor antagonists and downregulators.

Up to 80% of mammary carcinoma initially exhibit estrogen-dependent growth, which can be treated by aromatase inhibitors or SERMs/SERDs. To increase the options after failure of the hormonal therapy with these drugs, the search for alternatives with a different mode of action to prevent estrogen action is of high relevance. Therefore, this study focused on the inhibition of coactivator recruitment at the estrogen receptor (ER) by targeted attachment of bivalent compounds at the coactivator binding site besides the primary binding at the ligand binding domain. Eight homodimeric 4-[1-(4-hydroxyphenyl)-2-phenyl-1-butenyl]cinnamic acid (GW7604)- or cyclofenilacrylic acid-based ER ligands with diaminoalkane linkers (C2-C5) were synthesized and their effects on the ER subtypes were assessed in vitro. All compounds possessed full antagonistic potency at ERα/ß as determined in a transactivation assay. Furthermore, they exerted medium downregulatory effects dependent on the spacer length and did not stimulate the ER expression as observed for 4-hydroxytamoxifen. The cyclofenil-derived dimer with C4 spacer (15b) showed the highest binding affinity to ERα (RBA = 79.2%) and downregulated the ER content in MCF-7 cells with an efficiency of 38% at 1 µM.

Checkpoint kinase 1 is essential for fetal and adult hematopoiesis.

Checkpoint kinase 1 (CHK1) is critical for S-phase fidelity and preventing premature mitotic entry in the presence of DNA damage. Tumor cells have developed a strong dependence on CHK1 for survival, and hence, this kinase has developed into a promising drug target. Chk1 deficiency in mice results in blastocyst death due to G2/M checkpoint failure showing that it is an essential gene and may be difficult to target therapeutically. Here, we show that chemical inhibition of CHK1 kills murine and human hematopoietic stem and progenitor cells (HSPCs) by the induction of BCL2-regulated apoptosis. Cell death in HSPCs is independent of p53 but requires the BH3-only proteins BIM, PUMA, and NOXA. Moreover, Chk1 is essential for definitive hematopoiesis in the embryo. Noteworthy, cell death inhibition in HSPCs cannot restore blood cell formation as HSPCs lacking CHK1 accumulate DNA damage and stop dividing. Moreover, conditional deletion of Chk1 in hematopoietic cells of adult mice selects for blood cells retaining CHK1, suggesting an essential role in maintaining functional hematopoiesis. Our findings establish a previously unrecognized role for CHK1 in establishing and maintaining hematopoiesis.

Stereotactic Radiofrequency Ablation of Hepatocellular Carcinoma: a Histopathological Study in Explanted Livers.

This retrospective study was performed to evaluate the efficacy of three-dimensional (3D)-navigated multiprobe radiofrequency ablation (RFA) with intraprocedural image fusion for treatment of hepatocellular carcinoma (HCC) by histopathological examination. From 2009 to 2018, 97 patients (84 men, 13 women; median age, 60 years; range, 1-71) were transplanted after bridging therapy of 195 HCCs by stereotactic RFA (SRFA). The median interval between the first SRFA and transplantation was 6.8 months (range, 0-71). The rate of residual vital tissue (RVT) could be assessed in 188 of 195 lesions in 96 of 97 patients by histological examination of the explanted livers using hematoxylin and eosin (H&E) and Tdt-mediated UTP nick-end labeling (TUNEL) stains. Histopathological results were compared with the findings of the last computed tomography (CT) imaging before liver transplantation (LT). Median number and size of treated tumors were 1 (range, 1-8) and 2.5 cm (range, 1-8). Complete radiological response was achieved in 186 of 188 nodules (98.9%) and 94 of 96 patients (97.9%) and complete pathological response in the explanted liver specimen in 183 of 188 nodules (97.3%) and 91 of 96 patients (94.8%), respectively. In lesions ≥3 cm, complete tumor cell death was achieved in 50 of 52 nodules (96.2%). Residual tumor did not correlate with tumor size (P = 0.5). Conclusion: Multiprobe SRFA with intraprocedural image fusion represents an efficient, minimally invasive therapy for HCC, even with tumor sizes larger than 3 cm, and without the need of a combination with additional treatments. The results seem to justify the additional efforts related to the stereotactic approach.

Sensitivity of tumor surface brushings to detect human papilloma virus DNA in head and neck cancer.

OBJECTIVE: Human papilloma virus (HPV) induced head and neck squamous cell carcinoma (HNSCC) represents a distinct tumor subset. We questioned how accurately a brushing from the tumor surface detects HPV in patients with HNSCC. MATERIALS AND METHODS: Brushings from the tumor surface were compared with HPV DNA isolation from formalin-fixed and paraffin-embedded (FFPE) tumor biopsies, which served as the reference standard. In both matrices, HPV DNA was detected using a commercially available test kit. In addition, p16 was assessed in tumor biopsies by immunohistochemistry (IHC). The tumors were considered p16 positive if 70% or more of cancer cells expressed p16. RESULTS: 93 patients with HNSCC were included. Sensitivity and specificity of the brush test were 83% (95%CI: 67-92%) and 85% (95%CI: 72-93%). Results of p16 IHC were concordant with FFPE samples DNA determinations in 73/93 patients. In 53 patients (57%) the tumor was located in the oropharynx and in 40 patients (43%) the tumor was located in the non-oropharynx region. Sensitivity and specificity of the brush test in patients with oropharyngeal cancer was higher with 86% (95%CI: 70-95%) and 89% (95%CI: 65-99%). CONCLUSION: Superficial brushes from the tumor surface may be used to identify HPV positive HNSCC.

Targeting Gastrointestinal Stromal Tumor with 68Ga-Labeled Peptides: An In Vitro Study on Gastrointestinal Stromal Tumor-Cell Lines.

The gastrointestinal stromal tumor (GIST) is a rare disease with limited therapeutic options when resistance to tyrosine kinase inhibitor (TKI) treatment occurs. The authors investigated binding of various 68Ga-labeled peptides, targeting receptors reported to be overexpressed in GIST, in different cell lines. For this purpose, three GIST cell lines were tested: GIST-T1, GIST882 (Imatinib sensitive), and GIST430 (Imatinib resistant). DOTA-NT 8-13 (targeting NTR1), DOTA-TATE (targeting SSTR2), CP04 (a minigastrin derivative targeting CCK2-R), VIP-DOTA (targeting VPAC2-R), and 2 DOTA-bombesin derivatives [targeting gastrin releasing peptide receptors (GRPR)] were radiolabeled with 68Ga and incubated with the respective tumor cell and control cell lines. Membrane-bound and internalized activity was measured. Very low or no specific binding to GIST cells was found for all 68Ga-labeled DOTA peptides except for bombesin derivatives indicating no or very low expression of respective receptors. Related to GRPR a pronounced specific binding to all GIST cell lines with no preference related to TKI resistance status was found, both for an agonist (AMBA) with high internalization and for an antagonist (NeoBOMB1) with mainly membrane-bound activity (with up to >80% bound/mg protein). GRPR expression was confirmed by immunohistochemistry. The results show that radiolabeled bombesin analogues, especially antagonists are very promising candidates for targeting GIST.

Follicular growth after xenotransplantation of cryopreserved/thawed human ovarian tissue in SCID mice: dynamics and molecular aspects.

PURPOSE: To study the influence of xenotransplantation on follicular recruitment and growth in cryopreserved/thawed human ovarian tissue. METHOD: Two 3-mm pieces of cryopreserved/thawed human ovarian tissue obtained from female cancer patients (n = 11) were xenotransplanted into a subcutaneous neck pouch of 6-week-old ovarectomized SCID mice (n = 33) for 4 (n = 18) and 12 (n = 15) weeks. RESULT: Thirty-two out of 33 mice survived the entire observation periods. Graft recovery rate was 95.58 % (65 of 68 grafts). The percentages of primordial follicles after 4 weeks (P < 0.001) and 12 weeks (P = 0.009) of grafting were significantly lower in comparison to pregraft controls. The percentage of secondary follicle was significantly higher after 4 weeks of grafting (P = 0.018) and after 12 weeks (P = 0.001) of grafting in comparison to pregraft controls. Ki67 immunohistochemistry showed that proliferative follicles were significantly higher after 4 and 12 weeks of grafting compared to pregraft controls (P < 0.001). All follicles analyzed by TUNEL staining appeared healthy after xenotransplantation. The expression level of PTEN was reduced by 2.47-fold after 4 weeks of xenotransplantation, and this result was significant when 2-ΔCt were analyzed (P = 0.042). CONCLUSION: The higher proportion of growing follicles compared to resting follicles observed after xenotransplantation is most likely due to downregulation of PTEN gene expression followed by acceleration of follicular recruitment.

Low Beclin-1 expression predicts improved overall survival in patients treated with immunomodulatory drugs for multiple myeloma and identifies autophagy inhibition as a promising potentially druggable new therapeutic target: an analysis from The Austrian Myeloma Registry (AMR).

Beclin-1 is a key regulator of autophagy and has been suggested to be involved in the development of drug resistance in multiple myeloma (MM). We analyzed the expression of Beclin-1 in a retrospective cohort of 70 MMs. Beclin-1 expression did not influence overall survival (OS) and progression-free survival (PFS) in patients with therapy-naïve MM. In patients treated with immunomodulatory drugs (IMiDs) lack of or low Beclin-1 expression resulted in a significantly improved OS and PFS compared to those treated with bortezomib or nonnovel agents. Beclin-1 expression was more frequently detected in relapsed MM than in therapy-naïve MM probably being a hallmark of tumor progression and therapy resistance. If validated prospectively, Beclin-1 expression might identify patients prone to profit above average from IMiDs and enable a more rational allocation of antimyeloma therapies. Furthermore, the inhibition of autophagy could be a new promising target to improve response to treatment in the relapsed/refractory setting.

Pulmonary mucinous adenocarcinomas: architectural patterns in correlation with genetic changes, prognosis and survival.

Of pulmonary adenocarcinomas, about 25-30 % of cases is of a mucinous type. Mucinous adenocarcinomas are regarded as more aggressive compared to their non-mucinous counterparts. Invasive mucinous adenocarcinoma, colloid, and enteric adenocarcinomas are variants within adenocarcinomas. We investigated 76 invasive mucinous adenocarcinomas, including colloid variants, for predominant and secondary patterns, their different form of mucin storage and release, expression of cytokeratin 7 and 20, TTF1 and CDX2, MUC1, 2, and 5AC proteins, p14 and p16 proteins, possible rearrangements for EML4ALK and ROS1, as well as KRAS mutational status, and correlated this with survival. For comparison, 259 non-mucinous adenocarcinomas were selected. Overall survival for invasive mucinous adenocarcinomas corrected for T and N stage was not different from their non-mucinous counterpart. Most were of an acinar pattern. Neither pattern, nor type of mucin storage and release, such as luminal, extracellular, or goblet cell type had any influence on survival. Of adenocarcinomas expressing CK20, all but one expressed TTF1 either strongly or at least focally, and 8 co-expressed CDX2 focally. Most mucinous adenocarcinomas expressed either MUC1 or MUC5AC proteins, but rarely MUC2, while a few cases co-expressed both or all three. Loss of p16 expression correlated with worse outcome. KRAS mutation was found in 56 % of mucinous adenocarcinomas. Mutational status was neither correlated with architectural pattern nor survival. Codon 12 mutations were most frequent, and one case presented with KRAS mutations in codon 12 and 61. Goblet cell variants of mucinous adenocarcinomas presented predominantly with codon 12 mutations, while all colloid variants had KRAS mutation. Two cases had EML4 and ALK1 rearranged; ROS1 rearrangement was not found. Mucinous adenocarcinomas behave similar to non-mucinous variants. TNM stage is the most important factor followed by p16 loss predicting overall survival.

Multicenter Phase II Study Evaluating Two Cycles of Docetaxel, Cisplatin and Cetuximab as Induction Regimen Prior to Surgery in Chemotherapy-Naive Patients with NSCLC Stage IB-IIIA (INN06-Study).

BACKGROUND: Different strategies for neoadjuvant chemotherapy in patients with early stage NSCLC have already been evaluated. The aim of this study was to evaluate the tolerability and efficacy of a chemoimmunotherapy when limited to two cycles. METHODS: Between 01/2007 and 03/2010 41 patients with primarily resectable NSCLC stage IB to IIIA were included. Treatment consisted of two cycles cisplatin (40 mg/m2 d1+2) and docetaxel (75 mg/m2 d1) q3 weeks, accompanied by the administration of cetuximab (400 mg/m2 d1, then 250 mg weekly). The primary endpoint was radiological response according to RECIST. RESULTS: 40 patients were evaluable for toxicity, 39 for response. The main grade 3/4 toxicities were: neutropenia 25%, leucopenia 11%, febrile neutropenia 6%, nausea 8% and rash 8%. 20 patients achieved a partial response, 17 a stable disease, 2 were not evaluable. 37 patients (95%) underwent surgery and in three of them a complete pathological response was achieved. At a median follow-up of 44.2 months, 41% of the patients had died, median progression-free survival was 22.5 months. CONCLUSIONS: Two cycles of cisplatin/ docetaxel/ cetuximab showed promising efficacy in the neoadjuvant treatment of early-stage NSCLC and rapid operation was possible in 95% of patients. Toxicities were manageable and as expected. TRIAL REGISTRATION: EU Clinical Trials Register; Eudract-Nr: 2006-004639-31.

Low prevalence of HPV detection and genotyping in non-muscle invasive bladder cancer using single-step PCR followed by reverse line blot.

PURPOSE: To clarify the role of human papillomavirus (HPV) in non-muscle invasive bladder cancer, HPV-DNA was scrutinized in formalin-fixed, paraffin-embedded (FFPE) bladder cancer tissue using single-step PCR (HPV L1) for HPV detection, followed by reverse line blot (RLB) for genotyping. METHODS: A total of 186 patients who underwent transurethral resection of the bladder due to primary, non-muscle invasive bladder cancer from 2006 to 2009 were reviewed. A positive control group of 22 cervical tissues with cervical carcinoma was included. RESULTS: Histology confirmed urothelial carcinoma in all patients: primary CIS, pTa, pT1 and pTa + pT1 in 14 (7.5 %), 134 (72 %), 36 (19.4 %) and two (1.1 %) patients, respectively. A total of 119 (63.9 %) of them were classified as low-risk, while 67 (36.1 %) were high-risk cancers. Tumor recurrence and progression (≥pT2) were seen in 79 and 11 patients (mean follow-up 45 months). The presence of HPV-DNA by single-step PCR was detected in four (2.2 %) patients. HPV 16 and HPV 6 were positive in two (1.1 %) and one (0.6 %) patient, respectively In one case, no HPV genotype listed on the RLB assay could be identified. In the control group, the HPV infection rate was 100 %: HPV 16 in 12 (54.6 %) patients, HPV 16/18 in four (18.3 %) patients, HPV 18 in two (9.1 %) patients, HPV 16/45 in one patient (4.5 %), HPV 18/33 in one (4.5 %) patient, HPV 16/33 in one (4.5 %) patient and HPV 33 in one (4.5 %) patient. CONCLUSIONS: Our study demonstrates low prevalence of HPV infection in FFPE bladder cancer tissue, arguing against the etiological role of HPV in non-muscle urothelial carcinogenesis.

Clinical Neuropathology practice news 1-2014: pyrosequencing meets clinical and analytical performance criteria for routine testing of MGMT promoter methylation status in glioblastoma.

Testing of the MGMT promoter methylation status in glioblastoma is relevant for clinical decision making and research applications. Two recent and independent phase III therapy trials confirmed a prognostic and predictive value of the MGMT promoter methylation status in elderly glioblastoma patients. Several methods for MGMT promoter methylation testing have been proposed, but seem to be of limited test reliability. Therefore, and also due to feasibility reasons, translation of MGMT methylation testing into routine use has been protracted so far. Pyrosequencing after prior DNA bisulfite modification has emerged as a reliable, accurate, fast and easy-to-use method for MGMT promoter methylation testing in tumor tissues (including formalin fixed and paraffin-embedded samples). We performed an intra- and inter-laboratory ring trial which demonstrates a high analytical performance of this technique. Thus, pyrosequencing- based assessment of MGMT promoter methylation status in glioblastoma meets the criteria of high analytical test performance and can be recommended for clinical application, provided that strict quality control is performed. Our article summarizes clinical indications, practical instructions and open issues for MGMT promoter methylation testing in glioblastoma using pyrosequencing.

Possible pitfalls investigating cell death responses in genetically engineered mouse models and derived cell lines.

Genetically engineered mouse models are frequently used to identify pathophysiological consequences of deregulated cell death. Targeting pro-apoptotic or anti-apoptotic proteins of the extrinsic or intrinsic apoptotic signalling cascade is state of the art since more than two decades. Such animal models have been increasingly made use of over the past years to study loss- or gain-of-function consequences of one or more components of the molecular machinery leading to cell death. These studies have helped to separate redundant from non-redundant functions of apoptosis-related proteins in normal physiology and sometimes unravelled unexpected phenotypes. However, correct interpretation of data derived from knockout mice or derived cells and cell lines is often flawed by the comparison of cells originating from different inbred or mixed genetic backgrounds. Here we want to highlight some basic problems associated with genetic background-based modulation of cell death sensitivity and describe some methods that we use to investigate cell death responses in hematopoietic and non-hematopoietic cells. Thereby, we show that hematopoietic cells derived from wild type mice on a C57BL/6:129/SvJ recombinant mixed genetic background are significantly more resistant to spontaneous cell death or DNA-damage induced apoptosis in vitro than cells derived from inbred C57BL/6 mice. Furthermore, we show as an example that C57BL/6 mice are more susceptible to γ-irradiation induced cell death after whole body irradiation in vivo and subsequent T cell lymphomagenesis.

Necrosis-like death can engage multiple pro-apoptotic Bcl-2 protein family members.

Necroptosis is a physiologically relevant mode of cell death with some well-described initiating events, but largely unknown executioners. Here we investigated necrostatin-1 (Nec-1) sensitive death elicited by different necroptosis stimuli in L929 mouse fibrosarcoma cells, mouse embryonic fibroblasts (MEF) and bone marrow-derived macrophages. We found that TNFα- or zVAD-induced necroptosis occurs independently of the recently implicated executioners Bmf or PARP-2, but can involve the Bcl-2 family proteins Bid and Bak. Furthermore, this type of necroptosis is associated with mitochondrial cytochrome c release and partly sensitive to cyclosporine A inhibition, suggesting a cross talk with the mitochondrial permeability transition pore. Necroptosis triggered by cadmium (Cd) exposure caused fully Nec-1-sensitive and caspase-independent death in L929 cells that was associated with autocrine TNFα-mediated feed-forward signalling. In MEF Cd-exposure elicited a mixed mode of cell death that was to some extent Nec-1-sensitive but also displayed features of apoptosis. It was partly dependent on Bmf and Bax/Bak, proteins typically considered to act pro-apoptotic, but ultimately insensitive to caspase inhibition. Overall, our study indicates that inducers of "extrinsic" and "intrinsic" necroptosis can both trigger TNF-receptor signalling. Further, necroptosis may depend on mitochondrial changes engaging proteins considered critical for MOMP during apoptosis that ultimately contribute to caspase-independent necrotic cell death.