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The integrated stress response (ISR) is a central cellular adaptive program that is activated by diverse stressors including ER stress, hypoxia and nutrient deprivation to orchestrate responses via activating transcription factor 4 (ATF4). We hypothesized that ATF4 is essential for the adaptation of human glioblastoma (GB) cells to the conditions of the tumor microenvironment and is contributing to therapy resistance against chemotherapy. ATF4 induction in GB cells was modulated pharmacologically and genetically and investigated in the context of temozolomide treatment as well as glucose and oxygen deprivation. The relevance of the ISR was analyzed by cell death and metabolic measurements under conditions to approximate aspects of the GB microenvironment. ATF4 protein levels were induced by temozolomide treatment. In line, ATF4 gene suppressed GB cells (ATF4sh) displayed increased cell death and decreased survival after temozolomide treatment. Similar results were observed after treatment with the ISR inhibitor ISRIB. ATF4sh and ISRIB treated GB cells were sensitized to hypoxia-induced cell death. Our experimental study provides evidence for an important role of ATF4 for the adaptation of human GB cells to conditions of the tumor microenvironment characterized by low oxygen and nutrient availability and for the development of temozolomide resistance. Inhibiting the ISR in GB cells could therefore be a promising therapeutic approach.
The DNA damage response (DDR) is a vast network of molecules that preserves genome integrity and allow the faithful transmission of genetic information in human cells. While the usual response to the detection of DNA lesions in cells involves the control of cell-cycle checkpoints, repair proteins or apoptosis, alterations of the repair processes can lead to cellular dysfunction, diseases, or cancer. Besides, cancer patients with DDR alterations often show poor survival and chemoresistance. Despite the progress made in recent years in identifying genes and proteins involved in DDR and their roles in cellular physiology and pathology, the question of the involvement of DDR in metabolism remains unclear. It remains to study the metabolites associated with specific repair pathways or alterations and to investigate whether differences exist depending on cellular origin. The identification of DDR-related metabolic pathways and of the pathways that cause metabolic reprogramming in DDR-deficient cells may produce new targets for the development of new therapies.
In this thesis, nuclear magnetic resonance spectroscopy (NMR) was used to assess the metabolic consequence of the loss of two central DNA repair proteins with importance in diseases context, ATM and RNase H2, in haematological cells. An increase in intracellular taurine was found in RNase H2- and ATM-deficient cells compared to wild-type cells for these genes and in cells after exposition to a source of DNA damage. The rise in taurine does not appear to result from an increase in its biosynthesis from cysteine, but more likely from other cellular processes such as degradation pathways.
Overall, evidence for metabolic reprogramming in haematological cells with faults in DNA repair resulting from ATM or RNase H2 deficiencies or upon exposition to a source of DNA damage is presented in this study.
To explore and describe attitudes and opinions towards suicidality in healthcare professionals (HCPs) working with oncological patients. Methods: A 48-item online questionnaire was developed and distributed to HCPs working with cancer patients. Three hundred fifty-four answered questionnaires were analyzed. Results: The majority of HCPs reported that they were able to understand why a cancer patient would commit suicide (87.8%) or would seek help from an assisted suicide organization (ASO; 83.9%). The understandable reasons were pain and physical impairments (51.4%), social isolation (19.8%), loss of control and autonomy (18.1%), terminal disease (17.2%), loss of meaning (15.3%), desperation (14.7%), and psychic distress (9.3%). Personal experiences with suicidality lead only 44.8% of HCPs to believe that thereby they would be better able to understand a patients’ wish for suicide. Religion was negatively associated with understanding of suicide and why a cancer patient would seek help from an ASO. Knowledge of suicidality was positively associated with why a cancer patient would seek help from an ASO. Conclusions: There is still little knowledge in oncology about the relation of HCPs’ attitudes toward suicidality in their patients and how those attitudes influence their behavior, especially care and treatment of patients. More research on this topic is needed. It stands to reason that more education about suicidality in cancer patients seems likely to improve understanding and attitudes and thereby influence care for cancer patients.
Chimeric antigen receptor (CAR)-T cell therapies are on the verge of becoming powerful immunotherapeutic tools for combating hematological diseases confronted with pressing medical needs. Lately, CAR-NK cell therapies have also come into focus as novel therapeutic options to address hurdles related to CAR-T cell therapies, such as therapy-induced side effects. Currently, more than 500 CAR-T and 17 CAR-NK cell trials are being conducted worldwide including the four CAR-T cell products Kymriah, Yescarta, Tecartus and Breyanzi, which are already available on the market. Most CAR-T cell-based gene therapy products that are under clinical evaluation consist of autologous enriched T cells, whereas CAR-NK cell-based approaches can be generated from allogeneic donors. Besides modification based on a second-generation CAR, more advanced CAR-immune cell therapeutics are being tested, which utilize precise insertion of genes to circumvent graft-versus-host disease (GvHD) or employ a dual targeting approach and adapter CARs in order to avoid therapy resistance caused by antigen loss. In this review, we are going to take a closer look at the commercial CAR-T cell therapies, as well as on CAR-T and CAR-NK cell products, which are currently under evaluation in clinical trials, that are being conducted in Germany.
Bloodstream infections (BSI) are a frequent complication in patients with hematological and oncological diseases. However, the impact of different bacterial species causing BSI and of multiple BSI remains incompletely understood. We performed a retrospective study profiling 637 bacterial BSI episodes in hematological and oncological patients. Based on the 30-day (30d) overall survival (OS), we analyzed different types of multiple BSI and grouped BSI-associated bacteria into clusters followed by further assessment of clinical and infection-related characteristics. We discovered that polymicrobial BSI (different organisms on the first day of a BSI episode) and sequential BSI (another BSI before the respective BSI episode) were associated with a worse 30d OS. Different bacterial groups could be classified into three BSI outcome clusters based on 30d OS: favorable (FAV) including mainly common skin contaminants, Escherichia spp. and Streptococcus spp.; intermediate (INT) including mainly Enterococcus spp., vancomycin-resistant Enterococcus spp., and multidrug-resistant gram-negative bacteria (MDRGN); and adverse (ADV) including MDRGN with an additional carbapenem-resistance (MDRGN+CR). A polymicrobial or sequential BSI especially influenced the outcome in the combination of two INT cluster BSI. The presence of a polymicrobial BSI and the assignment into the BSI outcome clusters were identified as independent risk factors for 30d mortality in a Cox multivariate regression analysis. The assignment to a BSI outcome cluster and the differentiated perspective of multiple BSI open new insights into the prognosis of patients with BSI and should be further validated in other patient cohorts.
Purpose: Suicidality and suicidal ideation (SI) in oncology has long been an underestimated danger. Although there are cancer-specific distress screening tools available, none of these specifically incorporates items for SI. We examined the prevalence of SI in cancer patients, investigated the relation between SI and distress, and tried to identify additional associated factors. Methods: A cross-sectional study with patients treated for cancer in a primary care hospital was conducted. Psychosocial distress and SI in 226 patients was assessed. An expert rating scale (PO-Bado-SF) and a self-assessment instrument (QSC-R23) were used to measure distress. SI was assessed with item 9 of the PHQ-9. Data was descriptively analyzed, and correlations and group comparisons between clinically distressed and non-distressed patients were calculated. Results: SI was reported by 15% of patients. Classified as clinically distressed were 24.8% (QSC-R23) to 36.7% (PO-Bado-SF). SI was correlated with externally (rτ = 0.19, p < 0.001) and self-rated distress (rτ = 0.31, p < 0.001). Symptoms sufficiently severe for at least a medium major depressive episode were recorded in 23.5% of patients (PHQ-9). Factors associated with SI were feeling bad about oneself, feeling down, depressed, and hopeless, deficits in activities of daily life, psycho-somatic afflictions, social restrictions, and restrictions in daily life. Being in a steady relationship seemed to have a protective effect. Conclusions: SI is common in cancer patients. Distress and associated factors are increased in patients with SI. A distress screening with the ability to assess SI could be an important step in prevention, but more research is necessary.
Leukemia patients bearing t(6;11)(q27;q23) translocations can be divided in two subgroups: those with breakpoints in the major breakpoint cluster region of MLL (introns 9–10; associated mainly with AML M1/4/5), and others with breakpoints in the minor breakpoint cluster region (introns 21–23), associated with T-ALL. We cloned all four of the resulting fusion genes (MLL-AF6, AF6-MLL, exMLL-AF6, AF6-shMLL) and subsequently transfected them to generate stable cell culture models. Their molecular function was tested by inducing gene expression for 48 h in a Doxycycline-dependent fashion. Here, we present our results upon differential gene expression (DGE) that were obtained by the “Massive Analyses of cDNA Ends” (MACE-Seq) technology, an established 3′-end based RNA-Seq method. Our results indicate that the PHD/BD domain, present in the AF6-MLL and the exMLL-AF6 fusion protein, is responsible for chromatin activation in a genome-wide fashion. This led to strong deregulation of transcriptional processes involving protein-coding genes, pseudogenes, non-annotated genes, and RNA genes, e.g., LincRNAs and microRNAs, respectively. While cooperation between the MLL-AF6 and AF6-MLL fusion proteins appears to be required for the above-mentioned effects, exMLL-AF6 is able to cause similar effects on its own. The exMLL-AF6/AF6-shMLL co-expressing cell line displayed the induction of a myeloid-specific and a T-cell specific gene signature, which may explain the T-ALL disease phenotype observed in patients with such breakpoints. This again demonstrated that MLL fusion proteins are instructive and allow to study their pathomolecular mechanisms.
Leukemia patients bearing t(6;11)(q27;q23) translocations can be divided in two subgroups: those with breakpoints in the major breakpoint cluster region of MLL (introns 9–10; associated mainly with AML M1/4/5), and others with breakpoints in the minor breakpoint cluster region (introns 21–23), associated with T-ALL. We cloned all four of the resulting fusion genes (MLL-AF6, AF6-MLL, exMLL-AF6, AF6-shMLL) and subsequently transfected them to generate stable cell culture models. Their molecular function was tested by inducing gene expression for 48 h in a Doxycycline-dependent fashion. Here, we present our results upon differential gene expression (DGE) that were obtained by the “Massive Analyses of cDNA Ends” (MACE-Seq) technology, an established 3′-end based RNA-Seq method. Our results indicate that the PHD/BD domain, present in the AF6-MLL and the exMLL-AF6 fusion protein, is responsible for chromatin activation in a genome-wide fashion. This led to strong deregulation of transcriptional processes involving protein-coding genes, pseudogenes, non-annotated genes, and RNA genes, e.g., LincRNAs and microRNAs, respectively. While cooperation between the MLL-AF6 and AF6-MLL fusion proteins appears to be required for the above-mentioned effects, exMLL-AF6 is able to cause similar effects on its own. The exMLL-AF6/AF6-shMLL co-expressing cell line displayed the induction of a myeloid-specific and a T-cell specific gene signature, which may explain the T-ALL disease phenotype observed in patients with such breakpoints. This again demonstrated that MLL fusion proteins are instructive and allow to study their pathomolecular mechanisms.
Due to their physiological role in removing damaged cells, natural killer (NK) cells represent ideal candidates for cellular immunotherapy in the treatment of cancer. Thereby, the cytotoxicity of NK cells is regulated by signals on both, the NK cells as well as the targeted tumor cells, and the interplay and balance of these signals determine the killing capacity of NK cells. One promising avenue in cancer treatment is therefore the combination of NK cell therapy with agents that either help to increase the killing capacity of NK cells or sensitize tumor cells to an NK cell-mediated attack. In this mini-review, we present different strategies that can be explored to unleash the potential of NK cell immunotherapy. In particular, we summarize how modulation of apoptosis signaling within tumor cells can be exploited to sensitize tumor cells to NK cell-mediated cytotoxicity.