bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arsenic Trioxide Induced p53-Dependant Apoptotic Signals in a Temperature Sensitive (Ts) p53 Mutant, BRK Cell Line.
Authors: Akay Cagla , Gazitt Yair 
Published: April 2020

Abstract
Mutations in the p53 gene are the most common genetic abnormality in human cancers and are the cause for drug resistance. Arsenic trioxide (ATO) is an effective chemotherapeutic agent for the treatment of acute promyelocytic leukemia (APL) and is being tested in phase II studies in various types of cancers. We have previously shown that ATO is a potent inducer of apoptosis in multiple myeloma cells, engaging the intrinsic apoptotic pathway in cells expressing w.t. p53 whereas in cells expressing mutant p53, both the intrinsic and extrinsic apoptotic pathways are engaged. To further establish the differential effect of ATO in relation to the p53 status we studied the effect of temperature shift in temperature sensitive (Ts)-p53 expressing baby rat kidney (BRK) cells. We studied by Western immunoblotting the activation of the intrinsic and the extrinsic apoptotic pathways in ATO-induced apoptosis of BRK cells cultured at 32°C (w.t. p53 phenotype) and 37°C (mutant p53 phenotype). As expected, at 32°C, we observed a G1 arrest through activation of p21. We also observed depolarization of mitochondrial membrane; the release of cytochrome C and activation of caspase-9 and apoptosis as measured by Annexin V. We also observed release of SMAC at 32°C. In contrast, at 37°C we observed a G2/M arrest with no activation of p21 with activation of the extrinsic apoptotic pathway through early induction of TRAIL and TRAIL receptor- R2, activation of caspase-8, activation of BID, degradation of FLIP, rapid depolarization of mitochondrial membrane and release of AIF from mitochondria to the cytosol. We also demonstrate by flow cytometry and confocal imaging translocation of AIF to the nucleus in ATO-induced apoptosis at 37°C but not at 32°C. These results further substantiate our p53 model (Akay and Gazitt, Cell Cycle2:258–268, 2003).
The Fluctuation of Telomere Repeat Binding Factor 1 during Cell Cycle and Its Localization in Telomerase-Positive and Negative Cells.
Authors: Lan Jianping , Huang He , Zhu Yuanyuan , Sun Jie 
Published: April 2020

Abstract
Telomere is a nucleoprotein complex which caps the extreme ends of eukaryotic chromosomes. In human, telomere is composed of a tandem repeat array of TTAGGG hexanucleotide and bound to a set of specific proteins. These proteins function to maintain the integrity of chromosomes and genomic stability. Among these proteins, telomere repeat binding factor 1(TRF1) is the first telomere binding protein which was isolated by DNA affinity chromatography in 1995. TRF1 serves as a negative regulator of telomere length since TRF1 overexpression would elicit the shortening of telomere length in telomerase-positive cells. Meanwhile, overexpression of TRF1 would also induce the entry into mitosis and increase mitotic cells. These observation indicated TRF1 might participate in cell cycle regulation. However, the underlying mechanism in which TRF1 regulates the cell cycle and the endogenous level of TRF1 were not well-documented during cell cycle progression. To address these questions, we arrested HeLa cells at different phases by a combination of thymidine(5mM at final concentration) and nocodazole(20mM at final concentration) and detected the TRF1 levels by semi-quantitive Western Blotting assay. Cell cycle was verified by flow cytometry. Our results showed TRF1 level fluctuated coincided with cell cycle progression which reached the zenith at the M phase and went down to the nadir at G1/S point. Densitometry analysis demonstrated that the level of TRF1 at M phase was 3.9 times more than that at G1/S point(n=3, p&lt;0.01). These results suggested that TRF1 might be essential for proper cell cycle progression and it was likely to take part in regulation of cell cycle chechpoint. TRF1 is also expressed in telomerase-negative cells. To further discriminate the different functions of TRF1 and decipher its protein-protein interaction network in telomerase-positive and negative cells, full-length TRF1 cDNA was amplified by PCR and subsequently subcloned into pEGFP-C2 vector to express TRF1 tagged by enhanced green fluorescent protein. This construct was then transiently transfected into telomerase-negative cells(WI38-2RA) and telomerase-positive cells(HeLa). Immunoflourescent staining was employed to check the localization of TRF1 in these two kinds of cells. Although in both cells, TRF1 was distributed in a speckled pattern in the nuclei, TRF1 did exclusively colocalize with promyelocytic leukemia(PML) nuclear body in WI38-2RA cells but not in HeLa cells. PML fused with RARα due to chromosome15,17 translocation which led to disassembly of PML nucleur body in acute promyelocytic leukemia. These preliminary results suggested that TRF1 might have the different regulating mechanism and interacting network.
Overexpression of Par-4 Increases TRAIL-Induced Apoptosis in Neoplastic Lymphocytes by Diminishing Expression of Inhibitors-of-Apoptosis-Proteins and by Enforcing Activation of Initiator- and Executionercaspases.
Authors: Boehrer Simone , Nowak Daniel , Hoelzer Dieter , Mitrou Paris S. , Chow Kai Uwe 
Published: April 2020

Abstract
Acknowledging the previously demonstrated deregulated expression of the prostate-apoptosis-response-gene-4 (par-4) in ex vivo cells of patients suffering from acute and chronic lymphatic leukemias, we hypothesized that expression of par-4 determines sensitivity of neoplastic lymphocytes towards TRAIL-induced apoptosis. Evaluating this hypothesis we thus demonstrate, that par-4-transfected Jurkat cells incubated with the agonistic TRAIL-antibody CH11 exhibit a considerably increased rate of apoptosis as compared to their par-4-negative counterparts. Outlining the underlying molecular mechanisms we provide evidence, that par-4 promotes activation of the initiator caspase-8. Despite upregulating Bcl-2, overexpression of par-4 enhances cleavage of Bid and activation of caspase-9, resulting in an enforced activation of the executioner caspases-6 and -7, whereas caspase-3 remains unaltered. These effects are observed with a concomittant down-regulation of the inhibitor-of-apoptosis proteins cIAP-1 and XIAP. In conclusion, we here provide first evidence that expression of par-4 augments sensitivity of neoplastic lymphocytes to TRAIL-induced cell death, and describe the impact of par-4-expression on key molecules considered crucial in the induction of apoptosis via the extrinsic pathway.
Identification of a New t(4;11) Rearrangement Involving MLL and ArgBP2 in a Case of Infant Acute Myeloid Leukemia.
Authors: Tonelli Roberto , Nigro Luca Lo , Serravalle Salvatore , Montemurro Luca , Izzi Giancarlo , Pession Andrea 
Published: April 2020

Abstract
Rearrangement 11q23, involving MLL gene is mainly associated with M4/M5 acute myeloid leukemia (AML) and is characterized by poor prognosis and responsiveness to therapy. In this case blasts from an infant patient with monocytic AML were analyzed at diagnosis. The most frequent translocations of MLL, t(4;11) (40%, MLL-AF4) and t(9;11) (27%, MLL-AF9) were investigated by RT-PCR and resulted negative, meanwhile interphase FISH analysis, performed by using specific MLL probes, revealed a MLL gene translocation. Panhandle-PCR technique was performed to identify the partner gene and candidate clones DNA were sequenced to identify the unknown partner gene. The sequence analysis revealed the presence of a region of MLL connected with a region of ArgBP2 gene (chromosome band 4q35.1). The fusion gene is composed of the first 9 MLL exons and the last 3 ArgBP2 exons (exons 19–21) (Fig. 1). ArgBP2 belongs to vinexines family of protein adapters with three C-terminal SH3 domains, several potential phosphorilation sites for c-Abl and a serine/threonine rich region. The predicted fusion protein consists of AT-hooks and MT domains of MLL and the last ArgBP2 SH3 domain. MLL-ArgBP2 chimeric transcript was expressed in the blast while the reciprocal transcript ArgBP2-MLL was not. Identification of this new translocation of MLL gene confirms the high grade of MLL recombination in infant AMLs. Ongoing studies are in progress to analyze the mechanism leading to this new chromosomal translocation and the leukemogenic potentialities of the new MLL-ArgBP2 fusion protein.
Figure Figure
Specific Inhibition of hTERT by shRNA Sensitizes for Imatinib Mesylate in BCR-ABL-Positive Cells.
Authors: Sashida Goro , Tauchi Tetsuzo , Sumi Masahiko , Nakajima Akihiro , Ohyashiki Junko H. , Ohyashiki Kazuma 
Published: April 2020

Abstract
In the normal somatic cells, loss of telomere length leads to cell senescence appearing chromosome end-to-end fusion, and rearrangements. Most cancer cells exhibit constitutive telomerase activation and maintain telomere stability. Therefore, telomerase produces telomere repeats and represents the anti-cancer therapeutic target. Imatinib mesylate is a tyrosine kinase inhibitor, which inhibits BCR/ABL signal transductions. Despite of high remission rate of imatinib, the resistance to imatinib has been recognized as the major problem in treatment of the advanced or refractory CML. We have demonstrated that a dominant negative form of hTERT presents telomere shortening followed by proliferation arrest and apoptosis in leukemia cell lines. In the present study, we investigated the biological activity of hTERT specific short hairpin RNA (hTERT-shRNA) (kindly gifted from Dr. William C. Hahn, Dana-Farber Cancer Institute) in CML blastic-crisis cell line. We first disrupted the function of a catalytic subunit of telomerase complex, hTERT by expressing the hTERT-shRNA in the telomerase expressing K562 cell line, and found the inhibition of telomerase activity after single cell selections. We also found cumulative telomere shortenings in the hTERT-shRNA-expressing K562 cells. The hTERT-shRNA-expressing K562 cells showed increasing rate of apoptosis, and morphologically hyper-diploid cells followed by proliferation arrest. The hTERT-shRNA-expressing K562 cells reduced number of colony formation. The hTERT-shRNA-expressing K562 cells (population doubling 30) cytogenetically demonstrated end-to-end fusions and multi-centric chromosomes, which might be equivalent to disruptions of telomeric structure composed by repetitive DNA and telomere binding proteins. These results demonstrated that hTERT-shRNA effectively reduced the telomerase activity and induced telomere dysfunction in leukemia cells. Further we evaluated the combination efficacy of hTERT-shRNA and imatinib. The hTERT-shRNA-expressing K562 cells demonstrated significantly higher rate of apoptotic cells, and reduced proliferation activity compared with the parental K562 cells in the dose dependent manner of imatinib. These results suggest that the telomerase inhibition by hTERT-shRNA combined with imatinib is effective in BCR-ABL-positive leukemia.
BCL-6 Overexpression Predicts Poor Response to Reduced Immune Suppression Therapy in Children with Post-Transplantation Lymphoproliferative Disease (PTLD).
Authors: Porter Christopher C. , Liang Xiayuan , Albano Edythe A. 
Published: April 2020

Abstract
Background: PTLD is a well known complication of organ transplantation. While the understanding of this disease is increasing, the diagnosis and treatment remain challenging. The clinical, morphological, and molecular findings in PTLD vary widely. Reduction of immune suppression is the treatment of choice, but is effective in only 20–50% of patients. Mutations in the BCL6 gene have been demonstrated in some lymphomas and PTLD and may have prognostic implications. A single study, in which most subjects were adults, has suggested that BCL6 mutation in PTLD predicts a lack of response to reduced immunosuppression (IS).
Objectives: To determine if BCL-6 overexpression predicts poor response to reduced IS or decreased survival in children with PTLD.
Methods: Clinical data of patients identified with PTLD at The Children’s Hospital (TCH) from 1992–2002 were obtained, including age, type of organ transplanted, subtype of PTLD, treatment received, response to treatment, relapse free survival (RFS), and overall survival (OS). Archived specimens of lesions obtained at the time of diagnosis of PTLD were evaluated for the presence of BCL-6 expression by immunohistochemistry.
Results: Between 1992 and 2002, 486 organ transplants (211 heart, 107 hematopoietic stem cell (HSC), 86 liver, 82 kidney) were performed at TCH. During that same period, 20 children were diagnosed with 21 cases of PTLD. Eleven patients had liver transplants (12.7% of transplants), 5 had heart transplants (2.4%), 3 had HSC transplants (2.8%), and 1 had a kidney transplant (1.2%). Histologic classifications of PTLD included 1 follicular hyperplasia, 9 polymorphic PTLD, and 11 lymphomas. Only 5 of 20 patients responded to reduced IS. Overall mortality was 45% (9/20). BCL-6 was overexpressed in 7 of 18 evaluable specimens from 20 patients. None of the patients with BCL-6 overexpression responded to reduced IS (p=0.05). BCL-6 overexpression was associated with monomorphic histology (p=0.02), but did not predict RFS or OS.
Conclusions: BCL-6 expression is associated with monomorphic histology and non-response to reduced IS in children with PTLD. Larger, prospective studies of BCL-6 mutation and expression are needed to verify the clinical significance of these findings.
Histone Deacetylase Inhibitor Depsipeptide (FK228) Induces Apoptosis through Histone Acetylation and Upregulation of Annexin A1 in AML1-ETO Expressing Kasumi-1 Cells.
Authors: Tabe Yoko , Contractor Rooha , Radke Susanne , Andreeff Michael , Konopleva Marina 
Published: April 2020

Abstract
The t(8;21) translocation, found in 12% of AML, creates the chimeric fusion protein, AML-ETO, which recruits the HDAC complex to AML-1-dependent promoters resulting in transcription repression. Here, we studied the effects of HDAC inhibitor FK228 in the AML1-ETO positive AML cell line, Kasumi-1 and investigated molecular mechanisms of apoptosis induction in these cells. FK228 (5nM, 24 hours) caused marked growth inhibition, apoptosis induction (annexinV+/PI-; control 4.5±0.5%, FK228 24.6±2.6%), and cell cycle arrest (G1 phase; control 59.5%, FK228 76.7%, S phase; control 32.1%, FK228 17.8%). To investigate the molecular changes induced by FK228 we used cDNA array technology. After 24 hour exposure of Kasumi-1 cells, FK228 down-regulated (≤2-fold) 14 genes and up-regulated (≥2-fold) 123 genes including apoptosis and cell cycle regulating genes (Annexin A1; 3.5 fold, serglycin; 2.6 fold, Hes1; 2.2 fold, and TNFα; 2.1 fold increase). Among these genes, we focused on the pro-apoptotic protein Annexin A1, one of the calcium-dependent phospholipid binding proteins. First, we confirmed induction of Annexin A1 mRNA by FK228 using quantitative TaqMan RT-PCR (7.2±1.7 fold). As demonstrated by Western blot analysis, FK228 upregulated the expression of both, full-length Annexin A1 protein and a cleaved isoform of Annexin A1. To identify the critical histone residue modified by FK228 on the Annexin A1 promoter, we performed chromatin immunoprecipitation (ChIP) assays quantified by TaqMan PCR. FK228 increased H4 acetylation (6.7 ±1.8 fold) and H3-K9 acetylation (3.8 ±0.4 fold compared with control at 24 hours) in the Annexin A1 promoter. Next, we investigated effects of FK228 on apoptosis and signal transduction pathways that may modulate Annexin A1 function. As cleavage of the ubiquitous protein Annexin A1 is reported to be associated with caspase activation, the effect of caspase3 inhibitor Z-DEVD-cfm was examined. Z-DEVD pretreatment of Kasumi-1 cells resulted in increased viability and partial inhibition of apoptosis by FK228 (45% decrease in apoptosis with 20μM Z-DEVD). Z-DEVD partially inhibited FK228 induced Annexin A1 cleavage isoform indicating that cleavage of Annexin A1 involves both, caspase-dependent and independent mechanisms. Since activation of the MAPK/ERK pathway has recently been linked to histone de-acetylation, we examined the effects of FK228 on ERK phosphorylation. FK228 used at 5nM inhibited ERK signaling. Further experiments are ongoing to elucidate the possible association of MAPK inhibition, histone acetylation and Annexin A1 gene expression in Kasumi-1 cells.
In summary, these findings suggest that FK228 induces apoptosis and growth inhibition in Kasumi-1 cells in part by inducing Annexin A1 expression through histone acetylation of the promoter in association with caspase-dependent Annexin 1 cleavage and inhibition of MAPK signaling.
Clinical Significance of Prognostic Factors Related to Multidrug Resistance and Apoptosis for Prediction of Chemotherapy Outcomes in Acute Leukemia.
Authors: Ye Xu , Tan Huo , Feng Ying , Su Hang , Pang Ying 
Published: April 2020

Abstract
OBJECTIVE: To study the prognostic value of cd34, P-gp and Bcl-2 expression and MDR functional assays together with patients’ characteristics in patients with de novo acute leukemia.
METHODS: The expression levels of P-gp, CD34, Bcl-2 and the mean fluorescence intensity ratio of rhodamine 123 efflux assay (MIR (RE)) and intracellular daunorubicin accumulation assay (MIR (IDA)) of patients’ leukemia blast samples were prospectively determined with flow cytometry. The results of remission (CR) and non-remission (NR) patients were compared. Patients were given standard chemotherapy for remission induction.
RESULTS: CR patients were comparable to NR patients in age (39.2±23.0: 44.4±22.8, p=0.568, n=30). But NR patients had significantly higher peripheral white blood cell count than CR patients (72.84±78.74: 21.38±17.08, p=0.022, n=30). On the other hand, leukemia blasts samples of CR patients tend to express lower levels of CD34 (22.35±29.20: 46.18±39.5, p=0.084, n=30), P-gp (2.23±2.06: 11.95±22.90, p=0.111, n=30) and Bcl-2 (46.90±35.11: 57.02±31.97, p=0.434, n=30), but not significantly. However, the MIR (RE) (1.16±0.38 vs. 1.43±0.26, P=0.045, n=24) and MIR (IDA) (1.02±0.05 vs. 1.47±0.44, P =0.005, n=24) were both significantly lower in CR patients than in NR patients.
CONCLUSION: Leukemia patients with much higher peripheral WBC count at diagnosis were more difficult to reach remission after induction chemotherapy than patients with lower WBC counts. Age was not influential to chemotherapy results. The determination of MIR value in MDR functional assays is more valuable than expression levels of CD34, P-gp and Bcl-2 in the prediction of chemotherapy outcomes.
Relationship between DNA Index and Cellular Drug Resistance in Children with Newly Diagnosed Acute Lymphoblastic Leukemia.
Authors: Karakas Zeynep , Gokce Selim , Kuruca Serap Erdem , Demirel Gulderen Yanikkaya , Ozbek Ugur , Akcay Arzu , Aydogan Gonul , Devecioglu Omer 
Published: April 2020

Abstract
Leukemic cell ploidy is known risk factor in childhood leukemia. Hypodiploidy (DNA index &lt; 1.00 or chromosome number &lt;46) was shown as adverse prognostic factor in many study. The cause of poor prognosis is not known. Cellular drug resistance might provide important information on this subject. In this study, we want to evaluate LC50 (lethal concentration to 50% of cells) values of 7 different drugs in 34 newly diagnosed patient and compare those of hypodiploid with nonhypodiploid patients. DNA index was determined by flowcytometric analysis of cellular DNA content and cell cycle distribution with Coulter EPICS XL-MCL system on propidium iodide stained cells. DNA index was defined as the modal DNA content of leukemic cells compared with that of reference normal lymphocytes. Patients were divided in hypodiploid (DNA index &lt; 1.00) and nonhypodiploid (DNA index ≥ 1.00)
We carried out in vitro tests with a 4-day culture and a methyl-thiazol- tetrazolium (MTT) assay on bone morrow samples of patients to get LC50 values for 7 different classes of drugs(PRD, prednisolon; DEXA, dexamethasone; VCR, vincristine; ASP, l-asparaginase; ADR, adriamisin; DNR, daunorubisin; ARA-C, cytosine arabinoside) commonly used in treatment of ALL. Eigth patients (23.5%) were belong to hypodiploid group whereas 26 patiens (76.5%) were included in nonhypodiploid group. Sex and age distribution were not different between groups. MTT test were succesfully performed in 7 out 8 hypodiploid patient for each drug. Median LC50 values for PRD and ARA-C were similar. Median LC50 values of hypodiploid group for DEXA, VCR, ASP and ADR were 5.4, 3.5, 5.9 and 3.4 fold higher than those of nonhypodiploid group and were found to be statistically significant. Only the median LC50 value of hypodiploid group for DNR were lower than that of the nonhypodiploid group (p &lt;0.046).
In conclusion, cellular drug resistance might provide important information in relation to poor prognosis of hypodiploid ALL patients. It might also help to individualize the treatment according to drug resistance profiles. Further studies, large study groups and long-term follow-up are needed to confirm these results.
The Expression of mRNA and Enzyme Activity of Deoxycytidine- and Deoxyguanosine Kinases in Cell from Patients with Untreated B-Cell Chronic Lymphocytic Leukemia.
Authors: Lotfi Kourosh , Karlsson Karin , Juliusson Gunnar , Petersona Curt , Eriksson Staffan , Albertioni Freidoun 
Published: April 2020

Abstract
Chronic lymphocytic leukemia (CLL) is the most common leukemia in Europe and North America. The purine analogues fludarabine and cladribine have earned an important place in the treatment of CLL. Yet, the alkylating agent chlorambucil still remains as cornerstone of treatment. A gradual shift towards the use of purine analogues as the central component has become apparent however it is of greatest importance to strictly compare the efficacy of fludarabine and cladribine to have a basis for future clinical studies with these agents. In this study 59 patients included in the international Phase III Trial for untreated B-cell CLL, were randomized in order to evaluate the efficacy of chlorambucil, fludarabine, and cladribine, as primary treatment of patients with symptomatic B-cell CLL. Both fludarabine and cladribine are prodrugs and must be phosphorylated intracellularly to monophosphates by the nuclear/cytosol enzyme deoxycytidine kinase (dCK) and possibly by the mitochondrial enzyme deoxyguanosine kinase (dGK). DCK plays a pivotal roll in the activation of fludarabine and cladribine and it has previously been reported that resistance to these drugs is mainly due to deficiency of the dCK.
Before treatment, peripheral blood cells were isolated and the activity of dCK and dGK enzymes were analyzed in patient cells together with the dCK and dGK mRNA levels using the real-time quantitative PCR method.
The dGK activity was considerably lower (6 fold) than the dCK activity. The enzyme activities in samples from CLL patients varied about 20 and 30 folds for dCK and dGK, respectively.
The mRNA expression for dCK and dGK in patients showed also a large inter individual variability from 0,011 to 0,189 and 0,001 to 0,154 respectively.
There was no correlation between enzyme activity and mRNA levels in the studied CLL patients. We could not found any spliced mRNA dCK variant in our materiel or any mutation, which could explain the discrepancy between dCK activity, and mRNA levels. In conclusion, the results suggest that dCK and dGK expression is regulated at the (post) translational level in leukemic cells. However, studies of the relationship between enzyme activities and/or mRNA levels with clinical response to chemotherapy are underway and will be reported.