LEF-1 is a potential therapeutic target in the treatment of Chronic lymphocytic leukemia

B-Chronic lymphocytic leukemia (B-CLL) is characterized by accumulation of apoptotic resistant CD5+ B lymphocytes. There is an increased secretion of Wnt ligands indicating an autocrine loop leading to the extended survival of B-CLL cells. Lymphoid enhancer factor 1 (LEF-1) is a potent transcription factor regulating the expression of several Wnt induced target genes. A comprehensive gene expression profiling from two independent studies revealed that LEF-1 mRNA was ~3000 fold overexpressed in B-CLL when compared to its healthy counterpart. The objective of this present study is to demonstrate the therapeutic benefit of inhibiting LEF-1 expression in B-CLL cells using novel small molecule inhibitors CGP049090 and PKF115-584 in vivo and in vitro. In order to explore the anti-leukemic potential of CGP049090 and PKF115-584 we tested its effects on freshly isolated B-CLL cells, prolymphocytic cell line (JVM-3 & MEC-1) and in a subcutaneous mouse xenograft model. The present study shows that, in freshly isolated B-CLL cells there was high protein expression and nuclear localization of LEF-1 and β-catenin indicating active LEF-1 mediated transcription whereas LEF-1 remained undetectable in healthy B cells. Preliminary experiments of LEF-1 inhibition using siRNAs resulted in increased apoptosis indicating LEF-1 plays an important role in the survival of B-CLL cells. This observation was extended using CGP049090 and PKF-115584 as they induce dose dependent cytotoxicity in B-CLL, whereas the healthy B cells are not significantly affected. The half maximal inhibitory concentration (IC50) was less than 1 µM in primary B-CLL cells and cell lines whereas it was more than 5 µM in healthy B cells. CGP049090 and PKF-115584 induced apoptotic cell death in primary B-CLL cells and cell lines by cleavage of caspases 8, 9, 3 and 7 and subsequent cleavage of Poly (adenosine diphospate-ribose) polymerase (PARP). Both inhibitors also altered the expression of several anti-apoptotic proteins like X-linked Inhibitor of Apoptosis Protein (XIAP), Mantle cell lymphoma-1 (Mcl-1) and B cell lymphoma-2 (Bcl-2). Co-Immunoprecipitation experiments revealed that both the inhibitors effectively disrupt the β-catenin/LEF-1 interaction, resulting in the down regulation of LEF-1 target genes such c-myc, cyclin D1 and LEF-1. Furthermore, when the inhibitors were tested in an in vivo JVM-3 subcutaneous xenograft nude mouse model, more than 70% inhibition of tumor growth and an increase in the median survival of the treated group without leading to systemic toxicity was observed. Immunohistochemistry analysis of the tumor sections revealed LEF-1 down regulation and subsequent inhibition of proliferation by down regulation of Proliferating Cell Nuclear Antigen (PCNA) and increase in apoptosis (cleaved PARP). In summary, the data showed that LEF-1 is a potential therapeutic target in the treatment of B-CLL. Both CGP049090 and PKF115-584 showed potent inhibitory effects on the survival of CLL cells in vitro and in vivo without affecting the healthy cells. Both CGP049090 and PKF115-584 are hence, potential anti-cancer agents in B-CLL and other neoplastic malignancies with aberrant LEF-1/ T cell factor (TCF) transcriptional activity. Further investigations are warranted to determine the feasibility of these small molecules for therapeutic approach in humans

Gene expression and splicing alterations analyzed by high throughput RNA sequencing of chronic lymphocytic leukemia specimens.

BackgroundTo determine differentially expressed and spliced RNA transcripts in chronic lymphocytic leukemia specimens a high throughput RNA-sequencing (HTS RNA-seq) analysis was performed.MethodsTen CLL specimens and five normal peripheral blood CD19+ B cells were analyzed by HTS RNA-seq. The library preparation was performed with Illumina TrueSeq RNA kit and analyzed by Illumina HiSeq 2000 sequencing system.ResultsAn average of 48.5 million reads for B cells, and 50.6 million reads for CLL specimens were obtained with 10396 and 10448 assembled transcripts for normal B cells and primary CLL specimens respectively. With the Cuffdiff analysis, 2091 differentially expressed genes (DEG) between B cells and CLL specimens based on FPKM (fragments per kilobase of transcript per million reads and false discovery rate, FDR q < 0.05, fold change >2) were identified. Expression of selected DEGs (n = 32) with up regulated and down regulated expression in CLL from RNA-seq data were also analyzed by qRT-PCR in a test cohort of CLL specimens. Even though there was a variation in fold expression of DEG genes between RNA-seq and qRT-PCR; more than 90 % of analyzed genes were validated by qRT-PCR analysis. Analysis of RNA-seq data for splicing alterations in CLL and B cells was performed by Multivariate Analysis of Transcript Splicing (MATS analysis). Skipped exon was the most frequent splicing alteration in CLL specimens with 128 significant events (P-value <0.05, minimum inclusion level difference >0.1).ConclusionThe RNA-seq analysis of CLL specimens identifies novel DEG and alternatively spliced genes that are potential prognostic markers and therapeutic targets. High level of validation by qRT-PCR for a number of DEG genes supports the accuracy of this analysis. Global comparison of transcriptomes of B cells, IGVH non-mutated CLL (U-CLL) and mutated CLL specimens (M-CLL) with multidimensional scaling analysis was able to segregate CLL and B cell transcriptomes but the M-CLL and U-CLL transcriptomes were indistinguishable. The analysis of HTS RNA-seq data to identify alternative splicing events and other genetic abnormalities specific to CLL is an added advantage of RNA-seq that is not feasible with other genome wide analysis

Hmox1 Upregulation Is a Mutual Marker in Human Tumor Cells Exposed to Physical Plasma-Derived Oxidants

Increasing numbers of cancer deaths worldwide demand for new treatment avenues. Cold physical plasma is a partially ionized gas expelling a variety of reactive oxygen and nitrogen species, which can be harnesses therapeutically. Plasmas and plasma-treated liquids have antitumor properties in vitro and in vivo. Yet, global response signatures to plasma treatment have not yet been identified. To this end, we screened eight human cancer cell lines to investigate effects of low-dose, tumor-static plasma-treated medium (PTM) on cellular activity, immune-modulatory properties, and transcriptional levels of 22 redox-related genes. With PTM, a moderate reduction of metabolic activity and modest modulation of chemokine/cytokine pattern and markers of immunogenic cell death was observed. Strikingly, the Nuclear factor (erythroid-derived 2)-like 2 (nrf2) target heme oxygenase 1 (hmox1) was upregulated in all cell lines 4 h post PTM-treatment. nrf2 was not changed, but its baseline expression inversely and significantly correlated with hmox1 expression after exposure to PTM. Besides awarding hmox1 a central role with plasma-derived oxidants, we present a transcriptional redox map of 22 targets and chemokine/cytokine secretion map of 13 targets across eight different human tumor cell lines of four tumor entities at baseline activity that are useful for future studies in this field

Targeting malignant melanoma with physical plasmas

Melanoma is the deadliest form of cutaneous neoplasia. With a five-year survival rate of only 5–19%, metastatic melanoma presents severe challenges in clinical therapies. In addition, palliation is often problematic due to large numbers of fast growing metastasis. This calls for new therapeutic avenues targeting highly aggressive melanoma in palliative patients. One recently suggested innovative approach for eradication of topical tumor lesions is the application of cold physical plasma. This partially ionized gas emits a cocktail of reactive oxygen and nitrogen species (ROS/RNS). ROS/RNS have been shown to be a double-edged sword in fueling cancer growth at low doses but abrogating it at higher doses. The ROS/RNS output of plasma devices is tunable, and many studies have successfully decreased cancer cell growth in vitro and tumor burden in vivo. In general, increasing numbers of clinical trials suggest combination therapies to outperform monotherapies with regard to prognosis in patients. This review describes current challenges in melanoma treatment and highlights the concept of plasma therapy in experimental studies performed in melanoma research. Future perspectives are given that combine the usage of physical plasma with e.g. chemotherapy, immunotherapy, and ionizing radiation in melanoma medical oncology

Combination of chemotherapy and physical plasma elicits melanoma cell death via upregulation of SLC22A16

Malignant melanoma is an aggressive cancer that develops drug resistance leading to poor prognosis. Efficient delivery of chemotherapeutic drugs to the tumor tissue remains a major challenge in treatment regimens. Using murine (B16) and human (SK-MEL-28) melanoma cells, we investigated traditional cytotoxic agents in combination with cold physical plasma-derived oxidants. We report synergistic cytotoxicity of doxorubicin and epirubicin, and additive toxicity of oxaliplatin with plasma exposure in coefficient of drug interaction analysis. The combination treatment led to an increased DNA damage response (increased phosphorylation of ATM, γ-H2AX foci, and micronuclei formation). There was also an enhanced secretion of immunogenic cell death markers ATP and CXCL10 in cell culture supernatants following combination treatment. The observed synergistic effects in tumor cells was due to enhanced intracellular doxorubicin accumulation via upregulation of the organic cationic transporter SLC22A16 by plasma treatment. The doxorubicin uptake was reversed by pretreating cells with antioxidants or calcium influx inhibitor BTP2. Endoribonuclease-prepared siRNAs (esiRNA)-mediated knockdown of SLC22A16 inhibited the additive cytotoxic effect in tumor cells. SK-MEL 28 and THP-1 monocytes co-culture led to greater THP-1 cell migration and SK-MEL-28 cytotoxicity when compared with controls. Taken together, we propose pro-oxidant treatment modalities to sensitize chemoresistant melanoma cells towards subsequent chemotherapy, which may serve as therapeutic strategy in combination treatment in oncology

Activation of murine immune cells upon co-culture with plasma-treated B16F10 melanoma cells

Recent advances in melanoma therapy increased median survival in patients. However, death rates are still high, motivating the need of novel avenues in melanoma treatment. Cold physical plasma expels a cocktail of reactive species that have been suggested for cancer treatment. High species concentrations can be used to exploit apoptotic redox signaling pathways in tumor cells. Moreover, an immune-stimulatory role of plasma treatment, as well as plasma-killed tumor cells, was recently proposed, but studies using primary immune cells are scarce. To this end, we investigated the role of plasma-treated murine B16F10 melanoma cells in modulating murine immune cells' activation and marker profile. Melanoma cells exposed to plasma showed reduced metabolic and migratory activity, and an increased release of danger signals (ATP, CXCL1). This led to an altered cytokine profile with interleukin-1β (IL-1β) and CCL4 being significantly increased in plasma-treated mono- and co-cultures with immune cells. In T cells, plasma-treated melanoma cells induced extracellular signal-regulated Kinase (ERK) phosphorylation and increased CD28 expression, suggesting their activation. In monocytes, CD115 expression was elevated as a marker for activation. In summary, here we provide proof of concept that plasma-killed tumor cells are recognized immunologically, and that plasma exerts stimulating effects on immune cells alone. © 2019 by the authors

Cytochrome C oxidase Inhibition and Cold Plasma-derived Oxidants Synergize in Melanoma Cell Death Induction

Despite striking advances in the treatment of metastasized melanoma, the disease is often still fatal. Attention is therefore paid towards combinational regimens. Oxidants endogenously produced in mitochondria are currently targeted in pre-clinical and clinical studies. Cytotoxic synergism of mitochondrial cytochrome c oxidase (CcO) inhibition in conjunction with addition of exogenous oxidants in 2D and 3D melanoma cell culture models were examined. Murine (B16) and human SK-MEL-28 melanoma cells exposed to low-dose CcO inhibitors (potassium cyanide or sodium azide) or exogenous oxidants alone were non-toxic. However, we identified a potent cytotoxic synergism upon CcO inhibition and plasma-derived oxidants that led to rapid onset of caspase-independent melanoma cell death. This was mediated by mitochondrial dysfunction induced by superoxide elevation and ATP depletion. This observation was validated by siRNA-mediated knockdown of COX4I1 in SK-MEL-28 cells with cytotoxicity in the presence of exogenous oxidants. Similar effects were obtained with ADDA 5, a recently identified specific inhibitor of CcO activity showing low toxicity in vivo. Human keratinocytes were not affected by this combinational treatment, suggesting selective effects on melanoma cells. Hence, targeting mitochondrial CcO activity in conjunction with exogenous pro oxidant therapies may constitute a new and effective melanoma treatment modality

Combination of Gas Plasma and Radiotherapy Has Immunostimulatory Potential and Additive Toxicity in Murine Melanoma Cells In Vitro

Despite continuous advances in therapy, malignant melanoma is still among the deadliest types of cancer. At the same time, owing to its high plasticity and immunogenicity, melanoma is regarded as a model tumor entity when testing new treatment approaches. Cold physical plasma is a novel anticancer tool that utilizes a plethora of reactive oxygen species (ROS) being deposited on the target cells and tissues. To test whether plasma treatment would enhance the toxicity of an established antitumor therapy, ionizing radiation, we combined both physical treatment modalities targeting B16F10 murine melanoma cell in vitro. Repeated rather than single radiotherapy, in combination with gas plasma-introduced ROS, induced apoptosis and cell cycle arrest in an additive fashion. In tendency, gas plasma treatment sensitized the cells to subsequent radiotherapy rather than the other way around. This was concomitant with increased levels of TNFa, IL6, and GM-CSF in supernatants. Murine JAWS dendritic cells cultured in these supernatants showed an increased expression of cell surface activation markers, such as MHCII and CD83. For PD-L1 and PD-L2, increased expression was observed. Our results are the first to suggest an additive therapeutic effect of gas plasma and radiotherapy, and translational tumor models are needed to develop this concept further. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Völkisch und sozial? : Neonazistische Agitation gegen die neue EU-Freizügigkeit für Arbeitnehmerinnen

Wnt/β-catenin signalling pathway is crucial for the formation of many tissues and organs during development. In recent years, this pathway has also been found to regulate the biology of stem cells in the intestine and probably in other organs in adult life. Abnormal activation of Wnt/β-catenin signalling, which controls the expression of a high number of genes, is critical for the initiation and progression of most colorectal cancers. In line with this, the gene expression signature induced by activation of the Wnt/β-catenin pathway defines the intestinal stem cells present at the bottom of the crypts and also colon cancer stem cells. This supports the importance of inhibitors of the Wnt/β-catenin pathway as potential agents in colorectal cancer therapy. However, the complexity, wide activity in the organism modulating the biology of several cell types, and characteristics of this pathway have delayed the identification of suitable targets and so, the development of such inhibitors that are only now reaching the clinic.Peer reviewe

xCT (SLC7A11) expression confers intrinsic resistance to physical plasma treatment in tumor cells

Cold physical plasma is a partially ionized gas investigated as a new anticancer tool in selectively targeting cancer cells in monotherapy or in combination with therapeutic agents. Here, we investigated the intrinsic resistance mechanisms of tumor cells towards physical plasma treatment. When analyzing the dose-response relationship to cold plasma-derived oxidants in 11 human cancer cell lines, we identified four 'resistant' and seven 'sensitive' cell lines. We observed stable intracellular glutathione levels following plasma treatment only in the 'resistant' cell lines indicative of altered antioxidant mechanisms. Assessment of proteins involved in GSH metabolism revealed cystine-glutamate antiporter xCT (SLC7A11) to be significantly more abundant in the 'resistant' cell lines as compared to 'sensitive' cell lines. This decisive role of xCT was confirmed by pharmacological and genetic inhibition, followed by cold physical plasma treatment. Finally, microscopy analysis of ex vivo plasma-treated human melanoma punch biopsies suggested a correlation between apoptosis and basal xCT protein abundance. Taken together, our results demonstrate that xCT holds the potential as a biomarker predicting the sensitivity of tumor cells towards plasma treatment