[Diagnostic challenges in systemic mastocytosis with gastrointestinal symptoms]

A mastocytosis ritka megbetegedés: évente hozzávetőlegesen 1 új eset kerül felismerésre 100 000 lakosra vonatkoztatva. A betegség felismerése viszonylag egyszerű, ha bőrjelenség is kíséri, de van, hogy csak a mastocytaaktivációs tünetek megjelenése hívja fel a figyelmet a betegségre. A tünetek szerteágazóak lehetnek, egyénenként változó a megjelenésük, rendszerint több szervet érintenek, és gyakran allergiás betegségnek vélelmezik. A rohamokban jelentkező kipirulás, ájulás, fejfájás, gyomorégés mellett jellemző a vizes hasmenés, amely az élet minőségét nagyban rontja, de a rovarcsípés/darázscsípés okozta anaphylaxia életet veszélyeztető állapotot is okozhat azonnali beavatkozás nélkül. Jelen közleményünkben egy eset ismertetésével hívjuk fel a figyelmet arra, hogy a nem infektív eredetű, vizes hasmenés kivizsgálása során végzett vastagbéltükrözés során a makroszkóposan épnek látszó bélből származó hisztológia igazolhatja a kóros hízósejt-szaporulatot. Orv Hetil. 2024; 165(18): 717–720.

Targeting Melanoma-Associated Fibroblasts (MAFs) with Activated γδ (Vδ2) T Cells: An In Vitro Cytotoxicity Model

The tumor microenvironment (TME) has gained considerable scientific attention by playing a role in immunosuppression and tumorigenesis. Besides tumor cells, TME is composed of various other cell types, including cancer-associated fibroblasts (CAFs or MAFs when referring to melanoma-derived CAFs) and tumor-infiltrating lymphocytes (TILs), a subpopulation of which is labeled as γδ T cells. Since the current anti-cancer therapies using γδ T cells in various cancers have exhibited mixed treatment responses, to better understand the γδ T cell biology in melanoma, our research group aimed to investigate whether activated γδ T cells are capable of killing MAFs. To answer this question, we set up an in vitro platform using freshly isolated Vδ2-type γδ T cells and cultured MAFs that were biobanked from our melanoma patients. This study proved that the addition of zoledronic acid (1-2.5 µM) to the γδ T cells was necessary to drive MAFs into apoptosis. The MAF cytotoxicity of γδ T cells was further enhanced by using the stimulatory clone 20.1 of anti-BTN3A1 antibody but was reduced when anti-TCR γδ or anti-BTN2A1 antibodies were used. Since the administration of zoledronic acid is safe and tolerable in humans, our results provide further data for future clinical studies on the treatment of melanoma.

Next-Generation Sequencing-Based Genomic Profiling of Children with Acute Myeloid Leukemia

Pediatric acute myeloid leukemia (AML) represents a major cause of childhood leukemic mortality, with only a limited number of studies investigating the molecular landscape of the disease. Here, we present an integrative analysis of cytogenetic and molecular profiles of 75 patients with pediatric AML from a multicentric, real-world patient cohort treated according to AML Berlin-Frankfurt-Münster protocols. Targeted next-generation sequencing of 54 genes revealed 17 genes that were recurrently mutated in >5% of patients. Considerable differences were observed in the mutational profiles compared with previous studies, as BCORL1, CUX1, KDM6A, PHF6, and STAG2 mutations were detected at a higher frequency than previously reported, whereas KIT, NRAS, and KRAS were less frequently mutated. Our study identified novel recurrent mutations at diagnosis in the BCORL1 gene in 9% of the patients. Tumor suppressor gene (PHF6, TP53, and WT1) mutations were found to be associated with induction failure and shorter event-free survival, suggesting important roles of these alterations in resistance to therapy and disease progression. Comparison of the mutational landscape at diagnosis and relapse revealed an enrichment of mutations in tumor suppressor genes (16.2% versus 44.4%) and transcription factors (35.1% versus 55.6%) at relapse. Our findings shed further light on the heterogeneity of pediatric AML and identify previously unappreciated alterations that may lead to improved molecular characterization and risk stratification of pediatric AML.

Landscape of BCL2 Resistance Mutations in a Real-World Cohort of Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia Treated with Venetoclax

The oral, highly selective Bcl2 inhibitor venetoclax has substantially improved the therapeutic landscape of chronic lymphocytic leukemia (CLL). Despite the remarkable response rates in patients with relapsed/refractory (R/R) disease, acquired resistance is the leading cause of treatment failure, with somatic BCL2 mutations being the predominant genetic drivers underpinning venetoclax resistance. To assess the correlation between disease progression and the most common BCL2 mutations G101V and D103Y, sensitive (10−4) screening for the most common BCL2 mutations G101V and D103Y was performed in 67 R/R CLL patients during venetoclax single-agent or venetoclax–rituximab combination therapy. With a median follow-up time of 23 months, BCL2 G101V and D103Y were detected in 10.4% (7/67) and 11.9% (8/67) of the cases, respectively, with four patients harboring both resistance mutations. Ten out of eleven patients carrying BCL2 G101V and/or D103Y experienced relapse during the follow-up period, representing 43.5% of the cases (10/23) showing clinical signs of disease progression. All BCL2 G101V or D103Y variants were detected in patients receiving venetoclax as a continuous single-agent treatment while these mutations were not observed during or after fixed-duration venetoclax therapy. Targeted ultra-deep sequencing of BCL2 uncovered three additional variants in four patient samples obtained at relapse, suggesting convergent evolution and implying a cooperating role of BCL2 mutations in driving venetoclax resistance. This cohort is the largest R/R CLL patient population reported to date in which BCL2 resistance mutations were investigated. Our study demonstrates the feasibility and clinical value of sensitive screening for BCL2 resistance mutations in R/R CLL.

Successful thrombolytic therapy is associated with increased granulocyte CD15 expression and reduced stroke-induced immunosuppression

OBJECTIVES

Stroke-induced immunosuppression (SIIS) increases the risk of poststroke infections. We aimed to determine whether failed versus successful thrombolytic therapy (TT) resulted in SIIS-associated changes in peripheral granulocyte markers at 1 week following the insult.

METHODS

We collected peripheral blood samples from 19 patients with acute ischemic stroke undergoing TT within 6 h after the onset of their first symptoms and 7 days after the insult. Age-matched controls were sampled on one occasion. We compared the expression of CD15 and CD64 on monocytes, granulocytes, and lymphocytes using flow cytometry.

RESULTS

The proportion of granulocytes and CD15+ granulocytes was comparable between controls and stroke patients at both time points. While the proportion of CD15bright granulocytes was also comparable, the mean fluorescence intensity (MFI) of CD15 on this subset was reduced in stroke patients by day 7 but was overall higher at both time points compared to controls. The MFI of CD15 on granulocytes was lower in stroke patients with failed TT than in those with successful TT 1 week after the insult.

CONCLUSIONS

Our current results indicate that TT may not only acutely reduce the systemic inflammatory response following stroke but may also play a role in reversing SIIS at a later stage following the insult, as reflected by the higher expression of the CD15 marker on granulocytes following successful TT.

Revealing a Phenotypical Appearance of Ibrutinib Resistance in Patients With Chronic Lymphocytic Leukaemia by Flow Cytometry

Background: Ibrutinib is widely known as an effective and well-tolerated therapeutical choice of the chronic lymphocytic leukaemia (CLL). However, acquired resistance may occur during the treatment, causing relapse. Early detection of ibrutinib resistance is an important issue, therefore we aimed to find phenotypic markers on CLL cells the expression of which may correlate with the appearance of ibrutinib resistance.

Methods: We examined 28 patients’ peripheral blood (PB) samples (treatment naïve, ibrutinib sensitive, clinically ibrutinib resistant). The surface markers’ expression (CD27, CD69, CD86, CD184, CD185) were measured by flow cytometry. Furthermore, the BTK^C481S resistance mutation was assessed by digital droplet PCR. Moreover, the CLL cells’ phenotype of a patient with acquired ibrutinib resistance was observed during the ibrutinib treatment.

Results: The expression of CD27 (p = 0.030) and CD86 (p = 0.031) became higher in the clinically resistant cohort than in the ibrutinib sensitive cohort. Besides, we found that high CD86 and CD27 expressions were accompanied by BTK^C481S mutation. Our prospective study showed that the increase of the expression of CD27, CD69 and CD86 was noticed ahead of the clinical resistance with 3 months.

Conclusion: Our study suggests that the changes of the expression of these markers could indicate ibrutinib resistance and the examination of these phenotypic changes may become a part of the patients’ follow-up in the future.

Abstract 3730: Folic acid has a cell type- and dose-dependent effect on the genome and the epigenome of colorectal cancer cells

Synthetic vitamin B9, also known as folic acid (FA), is an extensively used nutritional supplement as well as an adjunctive medication in cancer therapy. However, there is increasing evidence that FA can promote the progression of established colorectal cancers (CRC); therefore, great care is required in the case of its application. In order to gain knowledge about the underlying mechanisms, we analyzed the genomic and the epigenomic effect of different FA supplies on two CRC cell lines with distinct molecular backgrounds. HT-29 and SW480 cells were kept in FA-free media (0 ng/mL) or treated with 100 ng/mL and 10000 ng/mL FA for 72 hours. Firstly, cell proliferation and cell viability alterations were determined with Supforhodamine B and AlamarBlue assays; then, cell cycle analysis was performed using fluorescence-activated cell sorting (FACS). Global DNA methylation level was investigated with the pyrosequencing of long interspersed nuclear element 1 (LINE-1) retrotransposons. Micronucleus scoring performed on DAPI- and anti-γ-H2AX-stained slides, as well as Comet assay, were used to detect the impact of FA on genome integrity. Finally, we analyzed gene expression alterations with Human Transcriptome Array (HTA) 2.0. Our data revealed that 100 ng/mL FA induced significant (p≤0.05) elevation (HT-29100: 128.4±24.9%) of HT-29 cell proliferation compared to the other two circumstances (HT-290: 101.3±13.5%; HT-2910000: 86.1±20.8%). The tendency of cell viability was analogous to the results detected during cell proliferation analyses (HT-290: 91.6±13.3%; HT-29100: 115.8±30.9%; HT-2910000: 64.1±20.2%). The genomic stability of FA-supplemented HT-29 samples was improved in a significant manner (p≤0.05), based on the results of micronucleus scoring (HT-290: 0.56±0.05%; HT-29100: 0.17±0.05%; HT-2910000: 0.25±0.09%) and Comet assay (HT-290: 37.4±3.5%; HT-29100: 31.2±3.4%; HT-2910000: 20.1±3.6%). However, in SW480 cells, remarkable alterations were not detected concerning these parameters. Fundamental differences were observed between the two cell lines in the case of cell cycle (HT-29: G0/1 phase dominance; SW480: S phase dominance) and global DNA methylation analysis (HT-29: 59.1±1.0; SW480: 49.0±0.2), but exposing them to different FA doses did not lead to significant changes. Gene expression alterations were more diverse, as genes involved in carcinogenesis were either up- (HES1, SLC7A11) or downregulated (CCL2) for FA supplementation. We concluded that the effect of FA was considerably influenced by the cell type and the applied FA concentration. Thereby, translating our in vitro results to patient care, we would emphasize the importance of genetic and epigenetic investigations coupled with the choice of proper FA dose upon CRC diagnosis to achieve the best disease outcome.

Citation Format: Sára Zsigrai, Alexandra Kalmár, Barbara Kinga Barták, Zsófia Brigitta Nagy, Krisztina Andrea Szigeti, Gábor Valcz, Titanilla Dankó, Anna Sebestyén, Gábor Barna, Zsolt Tulassay, Péter Igaz, István Takács, Béla Molnár. Folic acid has a cell type- and dose-dependent effect on the genome and the epigenome of colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3730.

An Extensive Quality Control and Quality Assurance (QC/QA) Program Significantly Improves Inter-Laboratory Concordance Rates of Flow-Cytometric Minimal Residual Disease Assessment in Acute Lymphoblastic Leukemia: An I-BFM-FLOW-Network Report

Simple Summary

Standardization of flow-cytometric assessment of minimal residual disease in acute lymphoid leukemia (ALL) is necessary to allow concordant multicentric application of the methodology. This is a prerequisite for internationally collaborative trials, such as the AIEOP-BFM-ALL and the ALL IC-BFM trial. We developed and applied a comprehensive training and quality control program involving a large number of international laboratories within the I-BFM consortium to complement standardization of the methodology with an educational component as well as with persistent quality control measures to allow large ALL treatment trials which use multi-laboratory FCM-MRD assessments for risk stratification of pediatric patients with ALL.

Abstract

Monitoring of minimal residual disease (MRD) by flow cytometry (FCM) is a powerful prognostic tool for predicting outcomes in acute lymphoblastic leukemia (ALL). To apply FCM-MRD in large, collaborative trials, dedicated laboratory staff must be educated to concordantly high levels of expertise and their performance quality should be continuously monitored. We sought to install a unique and comprehensive training and quality control (QC) program involving a large number of reference laboratories within the international Berlin-Frankfurt-Münster (I-BFM) consortium, in order to complement the standardization of the methodology with an educational component and persistent quality control measures. Our QC and quality assurance (QA) program is based on four major cornerstones: (i) a twinning maturation program, (ii) obligatory participation in external QA programs (spiked sample send around, United Kingdom National External Quality Assessment Service (UK NEQAS)), (iii) regular participation in list-mode-data (LMD) file ring trials (FCM data file send arounds), and (iv) surveys of independent data derived from trial results. We demonstrate that the training of laboratories using experienced twinning partners, along with continuous educational feedback significantly improves the performance of laboratories in detecting and quantifying MRD in pediatric ALL patients. Overall, our extensive education and quality control program improved inter-laboratory concordance rates of FCM-MRD assessments and ultimately led to a very high conformity of risk estimates in independent patient cohorts.

Rapamycin Plus Doxycycline Combination Affects Growth Arrest and Selective Autophagy-Dependent Cell Death in Breast Cancer Cells

Metabolic alteration is characteristic during tumour growth and therapy; however, targeting metabolic rewiring could overcome therapy resistance. mTOR hyperactivity, autophagy and other metabolic processes, including mitochondrial functions, could be targeted in breast cancer progression. We investigated the growth inhibitory mechanism of rapamycin + doxycycline treatment in human breast cancer model systems. Cell cycle and cell viability, including apoptotic and necrotic cell death, were analysed using flow cytometry, caspase activity measurements and caspase-3 immunostainings. mTOR-, autophagy-, necroptosis-related proteins and treatment-induced morphological alterations were analysed by Wes^TM, Western blot, immunostainings and transmission electron microscopy. The rapamycin + doxycycline combination decreased tumour proliferation in about 2/3rd of the investigated cell lines. The continuous treatment reduced tumour growth significantly both in vivo and in vitro. The effect after short-term treatment was reversible; however, autophagic vacuoles and degrading mitochondria were detected simultaneously, and the presence of mitophagy was also observed after the long-term rapamycin + doxycycline combination treatment. The rapamycin + doxycycline combination did not cause apoptosis or necrosis/necroptosis, but the alterations in autophagy- and mitochondria-related protein levels (LC3-B-II/I, p62, MitoTracker, TOM20 and certain co-stainings) were correlated to autophagy induction and mitophagy, without mitochondria repopulation. Based on these results, we suggest considering inducing metabolic stress and targeting mTOR hyperactivity and mitochondrial functions in combined anti-cancer treatments.

Limitations of VS38c labeling in the detection of plasma cell myeloma by flow cytometry

Plasma cell myeloma (multiple myeloma [MM]) is a malignant neoplasm originating from the plasma cells. Besides other methods, flow cytometric analysis of the patient's bone marrow aspirate has an important role in the diagnosis and also in the response assessment. Since the cell surface markers, used for identifying abnormal plasma cells, are expressed diversely and the treatment can also alter the phenotype of the plasma cells, there is an increasing demand for new plasma cell markers. VS38c is a monoclonal antibody that recognizes the CLIMP-63 protein in the membrane of the endoplasmic reticulum. CLIMP-63 is known to be expressed at high levels in normal and pathologic plasma cells in the bone marrow, thus VS38c antibody can be used to identify them. Although VS38c staining of plasma cells is reported to be constant and strong even in myeloma, we were wondering whether sample preparation can affect the staining. We have investigated the effect of different permeabilization agents and washing of the cells on the quality of the VS38c staining and found that in many cases the staining is inadequate to identify the plasma cells. We measured the VS38c staining of the bone marrow aspirates of 196 MM patients and observed that almost all cases showed bright staining with VS38c. However, permeabilization with mild detergent resulted in the appearance of a significant VS38c^dim subpopulation, which showed increased sensitivity to mechanical stress (centrifugation). Our results indicate that VS38c^dim MM cells can appear due to the improper permeabilization of the endoplasmic reticulum and this finding raises the possibility of the existence of a plasma cell subpopulation with different membrane properties. The significance of this population is unclear yet, but these cells can be easily missed with VS38c staining and can be lost due to centrifugation-induced lysis during sample preparation.

Screening and monitoring of the BTKC481S mutation in a real-world cohort of patients with relapsed/refractory chronic lymphocytic leukaemia during ibrutinib therapy

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has revolutionised the therapeutic landscape of chronic lymphocytic leukaemia (CLL). Acquired mutations emerging at position C481 in the BTK tyrosine kinase domain are the predominant genetic alterations associated with secondary ibrutinib resistance. To assess the correlation between disease progression, and the emergence and temporal dynamics of the most common resistance mutation BTK^C481S , sensitive (10^-4 ) time-resolved screening was performed in 83 relapsed/refractory CLL patients during single-agent ibrutinib treatment. With a median follow-up time of 40 months, BTK^C481S was detected in 48·2% (40/83) of the patients, with 80·0% (32/40) of them showing disease progression during the examined period. In these 32 cases, representing 72·7% (32/44) of all patients experiencing relapse, emergence of the BTK^C481S mutation preceded the symptoms of clinical relapse with a median of nine months. Subsequent Bcl-2 inhibition therapy applied in 28/32 patients harbouring BTK^C481S and progressing on ibrutinib conferred clinical and molecular remission across the patients. Our study demonstrates the clinical value of sensitive BTK^C481S monitoring with the largest longitudinally analysed real-world patient cohort reported to date and validates the feasibility of an early prediction of relapse in the majority of ibrutinib-treated relapsed/refractory CLL patients experiencing disease progression.

Lenalidomide abrogates the survival effect of bone marrow stromal cells in chronic lymphocytic leukemia

In the pathogenesis of chronic lymphocytic leukemia (CLL) the microenvironment plays an important role, as it produces survival signals and mediates drug resistance. Lenalidomide, which has immunomodulatory effect, can enhance the activation of T-, NK-cells and endothelial cells, however there are no data available whether it can modulate bone marrow stromal cells (BMSCs). In our study, we investigated the effects of lenalidomide on BMSCs and CLL cells. CLL cells were cultured alone or with BMSCs and were treated with lenalidomide. Apoptosis, immunophenotype, and cytokine secretion of BMSCs and CLL cells were determined by flow cytometry. Lenalidomide slightly increased the apoptosis of CLL cells and abrogated the anti-apoptotic effect of BMSCs on CLL cells. Lenalidomide treatment decreased the expression of antigens on CLL cells, which mediate the interactions with the microenvironment. Interestingly, lenalidomide enhanced the expression of IRF4 and the co-stimulatory molecule CD86. The secretion of several cytokines was not changed significantly by lenalidomide. CD49d-negative CLL cases were more sensitive to lenalidomide treatment. Our results suggest that lenalidomide has a limited effect on BMSCs, but it renders CLL cells more immunogenic and unresponsive to survival signals provided by BMSCs.

Identification of a novel resistance mechanism in venetoclax treatment and its prediction in chronic lymphocytic leukemia

BACKGROUND

The Bcl-2 inhibitor venetoclax has been recently introduced into the treatment of chronic lymphocytic leukemia. Venetoclax is a highly effective drug, however acquired resistance may make long-term treatment challenging. In our study, we present potential novel resistance mechanisms and prognostic markers that are potentially able to predict the early appearance of the resistance.

MATERIAL AND METHODS

Repeated complete blood counts, flow cytometric measurements, and physical examinations were performed during the patient follow-up. Clinical and laboratory parameters showed that the patient developed clinical resistance to venetoclax on day 450 of therapy. Resistance mutation analysis (D103Y) and apoptosis arrays from samples at the time of resistance were done.

RESULTS

We were able to identify the resistance mutations just a very low variant allele frequency level from the resistant samples. Furthermore we detected increased Bcl-2 expression in peripheral blood (PB), and XIAP overexpression in bone marrow (BM) that could lead to venetoclax resistance. We examined the immunophenotype of CLL cells and recognized that while the expression of CD86 did not change until day 270 of the treatment, since then its expression steadily increased. Moreover, we compared the expression of CD86 in the resistant PB and BM samples and did not find a notable difference between the compartments.

CONCLUSION

Our results imply that CLL cells may try to avoid the apoptotic effect of venetoclax through increased CD86 expression by activating antiapoptotic mechanisms. Confirmatory experiments are still required to unequivocally prove that CD86 is a prognostic marker, however, its predictive property during the venetoclax treatment is promising.

S-Adenosylmethionine Treatment of Colorectal Cancer Cell Lines Alters DNA Methylation, DNA Repair and Tumor Progression-Related Gene Expression

Global DNA hypomethylation is a characteristic feature of colorectal carcinoma (CRC). The tumor inhibitory effect of S-adenosylmethionine (SAM) methyl donor has been described in certain cancers including CRC. However, the molecular impact of SAM treatment on CRC cell lines with distinct genetic features has not been evaluated comprehensively. HT-29 and SW480 cells were treated with 0.5 and 1 mmol/L SAM for 48 h followed by cell proliferation measurements, whole-genome transcriptome and methylome analyses, DNA stability assessments and exome sequencing. SAM reduced cell number and increased senescence by causing S phase arrest, besides, multiple EMT-related genes (e.g., TGFB1) were downregulated in both cell lines. Alteration in the global DNA methylation level was not observed, but certain methylation changes in gene promoters were detected. SAM-induced γ-H2AX elevation could be associated with activated DNA repair pathway showing upregulated gene expression (e.g., HUS1). Remarkable genomic stability elevation, namely, decreased micronucleus number and comet tail length was observed only in SW480 after treatment. SAM has the potential to induce senescence, DNA repair, genome stability and to reduce CRC progression. However, the different therapeutic responses of HT-29 and SW480 to SAM emphasize the importance of the molecular characterization of CRC cases prior to methyl donor supplementation.

Coagulation FXIII-A Protein Expression Defines Three Novel Sub-populations in Pediatric B-Cell Progenitor Acute Lymphoblastic Leukemia Characterized by Distinct Gene Expression Signatures

Background: Leukemic B-cell precursor (BCP) lymphoblasts were identified as a novel expression site for coagulation factor XIII subunit A (FXIII-A). Flow cytometry (FC) revealed three distinct expression patterns, i.e., FXIII-A negative, FXIII-A dim, and FXIII-A bright subgroups. The FXIII-A negative subgroup was significantly associated with the “B-other” genetic category and had an unfavorable disease outcome.

Methods: RNA was extracted from bone marrow lymphoblasts of 42 pediatric patients with BCP-acute lymphoblastic leukemia (ALL). FXIII-A expression was determined by multiparameter FC. Genetic diagnosis was based on conventional cytogenetic method and fluorescence in situ hybridization. Affymetrix GeneChip Human Primeview array was used to analyze global expression pattern of 28,869 well-annotated genes. Microarray data were analyzed by Genespring GX14.9.1 software. Gene Ontology analysis was performed using Cytoscape 3.4.0 software with ClueGO application. Selected differentially expressed genes were validated by RT-Q-PCR.

Results: We demonstrated, for the first time, the general expression of F13A1 gene in pediatric BCP-ALL samples. The intensity of F13A1 expression corresponded to the FXIII-A protein expression subgroups which defined three characteristic and distinct gene expression signatures detected by Affymetrix oligonucleotide microarrays. Relative gene expression intensity of ANGPTL2, EHMT1 FOXO1, HAP1, NUCKS1, NUP43, PIK3CG, RAPGEF5, SEMA6A, SPIN1, TRH, and WASF2 followed the pattern of change in the intensity of the expression of the F13A1 gene. Common enhancer elements of these genes revealed by in silico analysis suggest that common transcription factors may regulate the expression of these genes in a similar fashion. PLAC8 was downregulated in the FXIII-A bright subgroup. Gene expression signature of the FXIII-A negative subgroup showed an overlap with the signature of “B-other” samples. DFFA, GIGYF1, GIGYF2, and INTS3 were upregulated and CD3G was downregulated in the “B-other” subgroup. Validated genes proved biologically and clinically relevant. We described differential expression of genes not shown previously to be associated with pediatric BCP-ALL.

Conclusions: Gene expression signature according to FXIII-A protein expression status defined three novel subgroups of pediatric BCP-ALL. Multiparameter FC appears to be an easy-to-use and affordable method to help in selecting FXIII-A negative patients who require a more elaborate and expensive molecular genetic investigation to design precision treatment.

Reduced GLP-1 response to a meal is associated with the CTLA4 rs3087243 G/G genotype

Although insulitis is the characteristic main feature of type 1 diabetes mellitus (T1DM), many aspects of β cell loss still remain elusive. Immune dysregulation and alterations in the dipeptidyl-peptidase-4-incretin system might have a role in disease development, but their connection is poorly understood. We assessed the associations of a few selected, immunologically relevant single nucleotide gene variants with the DPP-4-incretin system in individuals with T1DM and in healthy controls. Prandial plasma (total, active) GLP-1 levels, serum DPP-4 activity, CD25 and CTLA-4 expression of T cells and DPP4 rs6741949, CTLA4 rs3087243, CD25 rs61839660 and PTPN2 rs2476601 SNPs were assessed in 33 T1DM patients and 34 age-, gender-, BMI-matched non-diabetic controls without a family history of T1DM. CTLA-4 expression was lower in the Foxp3+CD25+ regulatory T cells from individuals homozygous for the CTLA4 rs3087243-G variant compared to those who carry an A allele. Prandial plasma total GLP-1 levels 45 min after a standardized meal were reduced in individuals homozygous for the CTLA4 rs3087243 G major allele compared to A allele carriers both in the entire study population (with statistical power over 90%) and within the T1DM group. Here we report for the first time a reduced total prandial GLP-1 plasma concentration in individuals with the CTLA4 rs3087243 G/G genotype. One may speculate that immune response-related L cell damage might possibly explain this novel association.

Effect of COPD on Inflammation, Lymphoid Functions and Progression-Free Survival during First-Line Chemotherapy in Advanced Non-small Cell Lung Cancer

Chronic obstructive pulmonary disease (COPD) is a common comorbidity of non-small cell lung cancer (NSCLC). COPD is characterized by systemic inflammation and lymphocyte dysfunction, mechanisms that are also known to accelerate progression of advanced (IIIB-IV) stage NSCLC. We aimed to find out whether COPD exerts an influence on tumor induced inflammatory and lymphoid responses and progression-free survival (PFS) after first-line treatment in advanced NSCLC. Patients suffering from NSCLC (n = 95), COPD (n = 54), NSCLC+COPD (n = 80) and healthy controls (n = 60) were included. PFS, neutrophil granulocyte and lymphocyte cell counts were recorded. Serum IFNγ, TNFα, VEGF concentrations were measured by using multiplex cytometric bead-based immunoassay. Prevalence of myeloid-derived suppressor cell populations (MDSC-s), and signs of T cell exhaustion were tested by using flow cytometry. Median PFS increased in the NSCLC+COPD group compared to NSCLC patients without COPD (7.4 vs 4.9 months, p < 0.01). NSCLC+COPD patients had 1.7 times (1.2-2.4) more likely to have longer PFS compared to NSCLC patients without COPD (Cox analysis, p < 0.01). Neutrophil cell counts, CRP, IFNγ and TNFα concentrations were all reduced in NSCLC+COPD (all p < 0.05 vs NSCLC). NSCLC+COPD was also associated with reduced serum IL-10 concentration and increased granzyme-B positive CD8 cell counts compared to NSCLC without COPD. The effects of VEGF and MDSC-s on systemic inflammation appeared to be blunted by COPD in patients suffering from advanced NSCLC. Concomitant COPD moderates tumor-induced inflammation and supports some effector lymphoid functions and thereby may be an independent positive predictive factor of longer PFS after first-line therapy in advanced NSCLC.

The Effect of CD86 Expression on the Proliferation and the Survival of CLL Cells

Micro-environment plays important role in the pathogenesis of CLL by providing protective niche for CLL cells. Several molecules play important role in communication between CLL cells and immune cells like CD86.Some of the data suggest that CLL patients with high CD86 level need earlier treatments and cells with higher CD86 expression has higher proliferation rate but the role of CD86 in the survival and proliferation of CLL cells is unclear. We investigated the effect of CD86 expression to CLL cells in 50 peripheral blood and 15 lymph node biopsy samples from CLL patients. Our results showed that the expressions of CD86 increased significantly after 7 day culturing in medium, or in the presence of bone marrow stromal cells (BMSCs). We found positive correlation between CD86 and CD23 expression (p < 0.05), but no correlation with other markers. Furthermore, no correlation were found between the CD86 expression and the proliferation of CLL cells. Analysis of clinical data showed that cases with high CD86 expression had lower level of serum lymphocyte count (p < 0.04) at the time of the diagnosis. CD86 shows multiple appearances in the lymph nodes containing pseudofollicules, but no correlation was found between CD86 positivity, and Ki67 positivity. Our results suggest that the use of CD86 molecule as a proliferation marker for CLL is highly questionable. However, the CD86 molecule may interfere with the immune system of patients with CLL by activating and depleting immune functions. That can be the reason why CD86 positivity may mean worse prognosis.

Survivin as a potential therapeutic target of acetylsalicylic acid in pituitary adenomas

Acetylsalicylic acid (ASA) is known as a cancer preventing agent, but there is no data available regarding the effect of ASA on pituitary cells.

We investigated 66 nonfunctioning (NFPA) and growth hormone (GH)-producing adenomas and 15 normal pituitary samples. Functional assays (cell viability, proliferation, flow cytometry cell cycle analysis, caspase-3 activation and DNA degradation) were applied to explore the effect of ASA, YM155 (survivin inhibitor), survivin-targeting siRNA and TNF-related apoptosis-inducing ligand (TRAIL) in RC-4B/C and GH3 cells. Pituitary adenoma xenografts were generated in immunocompromised mice.

We found that survivin was overexpressed and TRAIL was downregulated in NFPAs compared to normal pituitary tissue. ASA decreased proliferation but did not induce apoptosis in pituitary cells. Additionally, ASA treatment decreased cells in S phase and increased cells in G2/M phase of the cell cycle. Inhibition of survivin using an inhibitor or siRNA-mediated silencing reversed the ASA-induced growth inhibition partially. In addition, we also found survivin-independent effects of ASA on the cell cycle that were mediated through inhibition of cyclin A, cyclin dependent kinase 2 (CDK2) and phospho-CDK2. We also aimed to test the effect of acetylsalicylic acid in an animal model using RC-4 B/C cells, but in contrast to GH3 cells, RC-4 B/C cells failed to adhere and grow a xenograft.

We concluded that ASA inhibited the growth of pituitary adenoma cells. Survivin inhibition is a key mechanism explaining its antineoplastic effects. Our results suggest that inhibition of survivin with small molecules or ASA could serve as potential therapeutic agents in NFPA.

The effect of microenvironmental factors on the development of myeloma cells

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the accumulation of monoclonal plasma cells (PCs) in the bone marrow and other tissues. Although there are several new therapies, MM remains fatal. The interaction between MM cells and the bone marrow microenvironment promotes drug resistance and cancer cells survival. In our present work, we compared the antigen expression pattern of normal and pathological PCs and investigated the possible connections between various surface receptors, adhesion molecules, and recurrent genetic aberrations. We showed that the expression of CD29, CD27, and CD81 is lower in MM cells than in normal PCs. We found correlation of chromosome 11 hyperdiploidity and the decrease of CD27 expression. We demonstrated that MM cells with CD20 positivity also have CD28 expression. Multiple myeloma patients with active CD29 showed better response to treatment. Our results suggest that these changes may result in an alteration of the interaction between stromal cell and MM cell facilitating cell survival and the development of a more aggressive and resistant phenotype.

Cell cycle dependent RRM2 may serve as proliferation marker and pharmaceutical target in adrenocortical cancer

Adrenocortical cancer (ACC) is a rare, but agressive malignancy with poor prognosis. Histopathological diagnosis is challenging and pharmacological options for treatment are limited. By the comparative reanalysis of the transcriptional malignancy signature with the cell cycle dependent transcriptional program of ACC, we aimed to identify novel biomarkers which may be used in the histopathological diagnosis and for the prediction of therapeutical response of ACC. Comparative reanalysis of publicly available microarray datasets included three earlier studies comparing transcriptional differences between ACC and benign adrenocortical adenoma (ACA) and one study presenting the cell cycle dependent gene expressional program of human ACC cell line NCI-H295R. Immunohistochemical analysis was performed on ACC samples. In vitro effects of antineoplastic drugs including gemcitabine, mitotane and 9-cis-retinoic acid alone and in combination were tested in the NCI-H295R adrenocortical cell line. Upon the comparative reanalysis, ribonucleotide reductase subunit 2 (RRM2), responsible for the ribonucleotide dezoxyribonucleotide conversion during the S phase of the cell cycle has been validated as cell cycle dependently expressed. Moreover, its expression was associated with the malignancy signature, as well. Immunohistochemical analysis of RRM2 revealed a strong correlation with Ki67 index in ACC. Among the antiproliferative effects of the investigated compounds, gemcitabine showed a strong inhibition of proliferation and an increase of apoptotic events. Additionally, RRM2 has been upregulated upon gemcitabine treatment. Upon our results, RRM2 might be used as a proliferation marker in ACC. RRM2 upregulation upon gemcitabine treatment might contribute to an emerging chemoresistance against gemcitabine, which is in line with its limited therapeutical efficacy in ACC, and which should be overcome for successful clinical applications.

Increased Proportion of Hematopoietic Stem and Progenitor Cell Population in Cord Blood of Neonates Born to Mothers with Gestational Diabetes Mellitus

We assessed the hematopoietic stem and progenitor cell (HSPC) population in the cord blood of neonates born to mothers with gestational diabetes mellitus (GDM) in a hypothesis generating pilot study, due to that, neonatal polycythemia may be the consequence of GDM pregnancy. Forty-five pregnant women with GDM (last trimester mean HbA1C = 33.9 mmol/mol) and 42 (nondiabetic) control pregnant women were enrolled after their routine 75 g oral glucose tolerance test (OGTT) between the 24th and 28th gestational week (with expected differences in their mean routine clinical characteristics: plasma glucose at OGTT: 0′ = 5.07 vs. 4.62 mM, 120′ = 8.9 vs. 5.76 mM, age = 35.07 vs. 31.66 years, prepregnancy body mass index = 27.9 vs. 23.9 kg/m², GDM vs. control, respectively) on a voluntary basis after signing the informed consent. EDTA-treated cord blood samples were analyzed by flow cytometry and the software Kaluza1.2 using CD45 and CD34-specific fluorescent antibodies to identify the HSPC population (CD34⁺ cells within the CD45^dim blast gate). The proportion of CD34⁺CD45^dim HSPCs among the nucleated cells was significantly (P < 0.05, statistical power = 60.8%) higher in the cord blood samples of neonates born to mothers with GDM (median 0.38%) compared to neonates born to nondiabetic mothers (median 0.32%) and according to treatment types (P < 0.05) median: control 0.32%, GDM-diet only 0.37%, GDM-on insulin 0.45%; control versus GDM on insulin (P < 0.05). The increased proportion of circulating CD34⁺CD45^dim cells in the cord blood may possibly be related to altered fetal stem cell mobilization in GDM pregnancy, yet these results should be interpreted only as preliminary due to the small sample sizes.

Altered crosstalk in the dipeptidyl peptidase-4-incretin-immune system in type 1 diabetes: A hypothesis generating pilot study

Both GLP1(7)(-)(36) (via GLP1 receptor) and the dipeptidyl peptidase-4 (DPP4) cleaved form of GLP1 (GLP1(9)(-)(36), independently of GLP1R) may modulate the response of lymphocytes to cytokine stimuli. The incretin axis, CXCR3 (receptor of DPP4 ligand cytokines CXCL9-11) expression on T(reg)s and hematologic parameters were assessed in 34 patients with long standing type 1 diabetes (T1DM) and in 35 healthy controls. Serum DPP4 (sDPP4) activity, plasma total GLP1 and GLP1(7)(-)(36) concentrations were determined. GLP1(9)(-)(36) concentrations were calculated. CXCR3 expression (flow cytometry) was higher on the CD25(-/)(low)Foxp3(+) than on the CD25(+)Foxp3(+) T(reg)s independently from T1DM, suggesting that CD25(-/)(low)Foxp3(+) T(reg)s are possibly waiting for orientational chemotactic stimuli in a "standby mode". The higher sDPP4 activities in T1DM were inversely correlated with GLP1(7)(-)(36) levels and GLP1(9)(-)(36) levels directly with lymphocyte counts in controls. Our results might indicate an altered DPP4-incretin system and altered immunoregulation including a potentially dysfunctional GLP1(9)(-)(36) signaling in T1DM.

Low CD23 expression correlates with high CD38 expression and the presence of trisomy 12 in CLL

Chronic lymphocytic leukemia (CLL) is characterized by a neoplastic B-cell population coexpressing CD5 and CD23; however, the expression of CD23 is variable. In human, two isotypes of CD23 have been identified and related to different functions. The aim of our study was to investigate the relative expression of the two CD23 isotypes in CLL and find possible correlation with other prognostic factors. The expression of CD23 isotypes was analyzed in 54 cases of CLL by polymerase chain reaction (PCR) and quantitative real-time PCR. The immunophenotype of CLL cells was characterized by flow cytometry. We demonstrated a higher CD23a than CD23b expression of CLL cells. Our results also revealed two subsets of CLL cases with a distinct CD23 isotype expression pattern. Thirty-two percent of the cases (group CLL1) showed both low mRNA level of CD23 isotypes and high protein levels of CD20 and CD38 in contrast to group CLL2 with high CD23 mRNA levels. By correlating these results to the presence of prognostic factors determined by fluorescence in situ hybridization, we found that the majority of the cases of group CLL1 (14/17) carried trisomy 12. In summary, our results confirm a high CD23a/CD23b ratio of the CLL cells and demonstrate that in a subset of CLL cases, low CD23 expression together with high CD20 and CD38 expressions may serve as a surrogate for trisomy 12. Copyright © 2015 John Wiley & Sons, Ltd.

Rapamycin can restore the negative regulatory function of transforming growth factor beta 1 in high grade lymphomas

TGF-β1 (transforming growth factor beta 1) is a negative regulator of lymphocytes, inhibiting proliferation and switching on the apoptotic program in normal lymphoid cells. Lymphoma cells often lose their sensitivity to proapoptotic/anti-proliferative regulators such as TGF-β1. Rapamycin can influence both mTOR (mammalian target of rapamycin) and TGF-β signaling, and through these pathways it is able to enhance TGF-β induced anti-proliferative and apoptotic responses. In the present work we investigated the effect of rapamycin and TGF-β1 combination on cell growth and on TGF-β and mTOR signalling events in lymphoma cells. Rapamycin, an inhibitor of mTORC1 (mTOR complex 1) did not elicit apoptosis in lymphoma cells; however, the combination of rapamycin with exogenous TGF-β1 induced apoptosis and restored TGF-β1 dependent apoptotic machinery in several lymphoma cell lines with reduced TGF-β sensitivity in vitro. In parallel, the phosphorylation of p70 ribosomal S6 kinase (p70S6K) and ribosomal S6 protein, targets of mTORC1, was completely eliminated. Knockdown of Smad signalling by Smad4 siRNA had no influence on apoptosis induced by the rapamycin+TGF-β1, suggesting that this effect is independent of Smad signalling. However, apoptosis induction was dependent on early protein phosphatase 2A (PP2A) activity, and in part on caspases. Rapamycin+TGF-β1 induced apoptosis was not completely eliminated by a caspase inhibitor. These results suggest that high mTOR activity contributes to TGF-β resistance and lowering mTORC1 kinase activity may provide a tool in high grade B-cell lymphoma therapy by restoring the sensitivity to normally available regulators such as TGF-β1.

Extension of the CD4⁺Foxp3⁺CD25(-/low) regulatory T-cell subpopulation in type 1 diabetes mellitus

Regulatory T-cells (Treg) have a crucial role in limiting physiologic autoreactivity. Foxp3 is a master regulator transcription factor of Treg differentiation and active Treg cells express high levels of IL-2 receptor α-chain (CD25). The aim of our study was to assess the key markers of Treg cell function in type 1 diabetic (T1DM) and control subjects by flow cytometry. The proportion of CD25(-/low) cells among CD4(+)Foxp3(+) Treg cells was higher in T1DM patients that might suggest a shifted proportion of the incomplete/reserve and the fully active (CD4(+)Foxp3(+)CD25(+)) Treg cell subpopulations in T1DM, similarly to other Th1-mediated autoimmune diseases. In addition to the decreased expression of CD25 and CTLA-4 in T1DM patients, a positive correlation was observed between the CD25 expression on CD4(+) and the CTLA-4 expression in CD8(-) T-lymphocytes both in the T1DM and in the healthy control group. Our results suggest an impaired balance of CD25(+) and CD25(-/low) Treg cells in T1DM which might reflect a decreased late phase peripheral Treg activation even in patients with a mean disease duration of more than a decade.

Mammalian target of rapamycin (mTOR) activity dependent phospho-protein expression in childhood acute lymphoblastic leukemia (ALL)

Modern treatment strategies have improved the prognosis of childhood ALL; however, treatment still fails in 25–30% of patients. Further improvement of treatment may depend on the development of targeted therapies. mTOR kinase, a central mediator of several signaling pathways, has recently attracted remarkable attention as a potential target in pediatric ALL. However, limited data exists about the activity of mTOR. In the present study, the amount of mTOR activity dependent phospho-proteins was characterized by ELISA in human leukemia cell lines and in lymphoblasts from childhood ALL patients (n = 49). Expression was measured before and during chemotherapy and at relapses. Leukemia cell lines exhibited increased mTOR activity, indicated by phospho-S6 ribosomal protein (p-S6) and phosphorylated eukaryotic initiation factor 4E binding protein (p-4EBP1). Elevated p-4EBP1 protein levels were detected in ALL samples at diagnosis; efficacy of chemotherapy was followed by the decrease of mTOR activity dependent protein phosphorylation. Optical density (OD) for p-4EBP1 (ELISA) was significantly higher in patients with poor prognosis at diagnosis, and in the samples of relapsed patients. Our results suggest that measuring mTOR activity related phospho-proteins such as p-4EBP1 by ELISA may help to identify patients with poor prognosis before treatment, and to detect early relapses. Determining mTOR activity in leukemic cells may also be a useful tool for selecting patients who may benefit from future mTOR inhibitor treatments.

Enhancement of 5-fluorouracil efficacy on high COX-2 expressing HCA-7 cells by low dose indomethacin and NS-398 but not on low COX-2 expressing HT-29 cells

The antiproliferative effect of 5-fluorouracil (5-FU) in the presence of low dose non-steroidal anti-inflammatory drugs (NSAIDs) on high cyclooxygenase-2 (COX-2)-expressing HCA-7 and low COX-2-expressing HT-29 colon carcinoma cell lines was investigated. Pharmacogenetic parameters were studied to characterize the 5-FU sensitivity of the two cell lines. Thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms were determined by PCR analysis. Cell proliferation was measured by SRB assay, cell cycle distribution and apoptosis by FACS analysis. Cyclooxygenase expression was detected by Western blot and also by fluorescence microscopy. Prostaglandin E(2) (PGE(2)) levels were investigated with ELISA kit. The HT-29 cell line was found to be homozygous for TS 2R and 1494ins6 and T homozygous for MTHFR 677 polymorphisms predicting high 5-FU sensitivity (IC(50): 10 microM). TS 3R homozygosity, TS 1496del6 and MTHFR 677CT heterozygosity may explain the modest 5-FU sensitivity (IC(50): 1.1 mM) of the HCA-7 cell line. Indomethacin and NS-398 (10 microM and 1.77 microM, respectively) reduced the PGE(2) level in HCA-7 cells (>90%). Low concentrations of NSAIDs without antiproliferative potency increased the S-phase arrest and enhanced the cytotoxic action of 5-FU only in HCA-7 cells after 48-hours treatment. The presented data suggested that the enhancement of 5-FU cytotoxicity by indomethacin or NS-398 applied in low dose is related to the potency of NSAIDs to modulate the cell-cycle distribution and the apoptosis; however, it seems that this effect might be dependent on cell phenotype, namely on the COX-2 expression.

Effect of somatostatin analogue octreotide in medulloblastoma in xenograft and cell culture study

BACKGROUND

The effect and possible timing of nonradiolabeled somatostatin analogue octreotide are still not determined in the treatment of medulloblastoma, while the presence of somatostatin receptor type-2 (SSTR2) is proved in the majority of medulloblastoma by several authors.

PROCEDURES

Daoy, SSTR2A positive medulloblastoma cell culture was tested with octreotide in monotherapy and combined with cisplatin, etoposide, and vincristine. Daoy medulloblastoma mice xenograft was treated with octreotide alone.

RESULTS

In monolayer cell culture high-dose octreotide (44 microM) resulted in mitotic inhibition with parallel increment of apoptosis. Combination with cytostatic drugs did not result in additive or synergistic effect, but vincristine was partially antagonized. In medulloblastoma xenograft, octreotide monotherapy (100 microg/kg/day for 10 days) resulted in partial tumor growth inhibition.

CONCLUSIONS

High concentration of nonradiolabeled octreotide may have role in the treatment of medulloblastoma by long-term administration. Concomitant administration of octreotide with widely used cytostatic drugs against medulloblastoma will not have beneficial impact.

The cut-off levels of CD23 expression in the differential diagnosis of MCL and CLL

Flow cytometric analysis of CD23 expression in CD5-positive B-cells is a widely applied method in the differential diagnosis of chronic lymphocytic leukaemia (CLL) and mantle cell lymphoma (MCL). According to the most accepted criteria, the leukaemic cell population is CD19/CD5/CD23 triple positive in CLL but CD23-negative in MCL. Recently, several groups have reported CD23-positive MCL cases; however, these studies mostly analysed only CD23 positivity but not intensity. To determine the role and the cut-off levels of CD23 positivity and intensity in the differential diagnosis of CLL and MCL, 26 cases of MCL and 84 cases of CLL were compared using flow cytometric analysis. Our results suggest that high values of CD23 positivity (>92.5%) and/or high fluorescence intensity (>44.5 mean fluorescence intensity (MFI)) of CD23 are related to CLL, whereas low CD23 positivity (<30%) is related to MCL. However, cases with intermediate CD23 positivity (between 30 and 92.5%) and lower intensity (<44.5 MFI) can either belong to CLL or MCL. In these cases, additional tests such as FISH analysis of the translocation t(11;14) or immunohistochemical detection of cyclin D1 overexpression are required to differentiate CLL from MCL.

Antiproliferative and apoptotic effects of mycophenolic acid in human B-cell non-Hodgkin lymphomas

Mycophenolic acid (MPA)/mycophenolate mofetil (MMF), a powerful immunosuppressive agent was tested on human B-lymphoma cells (Epstein-Barr virus +/-) in vitro and in SCID mouse xenograft model. Proliferation, apoptotic activity and tumor volume were evaluated. MPA inhibited lymphoma cell proliferation and induced apoptosis (50-60% at 72 h). In vivo, oral administration significantly inhibited subcutaneous tumor growth. Immunohistochemistry showed significantly decreased proliferation rate and higher apoptotic activity in tumors treated with MMF. Xenografted lymphoma cells remained sensitive to MPA. Our results suggest that MPA may be recommended as an additional component of lymphoma chemotherapeutical regimens, with special considerations to post-transplant lymphomas.

Smad4-independent, PP2A-dependent apoptotic effect of exogenous transforming growth factor beta 1 in lymphoma cells

B-lymphoid tumor cells are often less sensitive than their normal counterparts or insensitive to transforming growth factor beta1 (TGFb) effects. We studied the apoptotic effect of exogenous TGFb in B-lymphoma cells, focusing on the activity and the role of Smad and protein phosphatase/kinase signals. Recombinant TGFb treatment and Smad4 siRNA transfection were used in HT58 B-NHL lymphoma cells in vitro. Gene expression and apoptosis were detected by RT-PCR, Western blot analysis and flow cytometry. The role of MEK1 kinase and PP2A activity--measured with a phosphatase assay--were assessed with the help of specific inhibitors. Smad4 siRNA treatment completely abolished TGFb-induced early gene upregulation, indicating the absence of the rapid activation of Smad signaling. Moreover, functional inhibition of Smad4 had no influence on TGFb-induced apoptosis, but it was dependent on PP2A phosphatase activation, ERK1/2 and JNK inactivation in lymphoma cells. The results prove that exogenous TGFb uses Smad4-independent, alternative (PP2A/PP2A-like dependent) signaling pathways for apoptosis induction in lymphoma cells. Further studies are needed to clarify the possible role and involvement of Smad4-independent effects of TGFb in normal and malignant lymphoid cells and in cells of the tumor microenvironment.

Activity of the notch-signalling pathway in circulating human chronic lymphocytic leukaemia cells

Dysregulation of the Notch-pathway has been implicated in the pathogenesis of chronic lymphocytic leukaemia (B-CLL). We characterized the mRNA expression of Notch pathway elements in circulating normal B- and B-CLL cells, and compared expression profiles with clinical and prognostic data. Similar expression profiles were found in normal B-cells and B-CLL cells, however, most B-CLL samples showed lower Hairy/Enhancer of Split-1 expression than normal B-cells, which suggests that the pathway is not over-activated in B-CLL. The expression of Notch-pathway genes did not correlate with other prognostic factors of B-CLL. The importance of Notch-signalling in CLL cells in lymphatic tissue microenvironments remains to be determined.

Different ways to induce apoptosis by fenretinide and all-trans-retinoic acid in human B lymphoma cells

All-trans-retinoic acid (ATRA) and its synthetic analog fenretinide (4HPR) are potent anticancer drugs. Only a few reports are available about the effects of retinoids on B lymphoma cells. In our study, non-Hodgkin lymphoma cells (HT58) were treated with ATRA and 4HPR. Both agents induced cell death time- and dose-dependently. Reactive oxygen species (ROS) production was elevated in 4HPR-treated cells, but not in ATRA-treated cells. The depolarization of the mitochondrial membrane occured earlier after ATRA than after 4HPR treament. Z-VAD-fmk, the general caspase inhibitor, decreased the DNA fragmentation in ATRA-treated cells, but simultaneously increased necrosis. However, z-VAD-fmk did not influence the DNA fragmentation in 4HPR-treated cells. Endonuclease G was released from the mitochondria during 4HPR treatment, which could be an inducer for caspase-independent DNA fragmentation. Our results suggest that natural (ATRA) and synthetic (4HPR) retinoids induce different apoptotic pathways in B lymphoma cells, which is particularly relevant for their potential use in leukemia treatment.

Smad signal and TGFβ induced apoptosis in human lymphoma cells

Transforming growth factor beta1 (TGF beta1) has antiproliferative and/or apoptotic effect on lymphoid cells. In certain lymphomas exogenous TGF beta1 is able to induce apoptosis, however many lymphoid malignancies are resistant to the endogenous TGF beta1 production. We studied the expression and the activity of TGF beta1 signalling components in B cell lymphoma cell lines (e.g. HT 58 cells) and in isolated human peripheral mononuclear cells (PBMCs) from healthy individual's and B-CLL patient's blood. We found that all signal transducer Smads (Smad2,-3; Smad4) and at least one of the inhibitory Smads (Smad6,-7) were expressed in non-treated lymphoma cells, but the inhibitory Smads did not in normal/control PBMCs. However, after TGF beta1 treatment Smad6 disappeared, while the expression of Smad7 increased in HT 58 cells. The activity of Smad signals was proved by phosphorylation of Smad2, nuclear translocation of Smad2/3, and the increased expression of Smad-dependent gene, TIEG in TGF beta1 treated lymphoma cells. These results showed that Smad signaling is available in certain different human lymphoma cells, however ISmads expression could inhibit the signal transmission. This findings indicates that the lost sensitivity of lymphoma cells toward a physiological regulatory factor could be reversed.

[Mevastatin induced apoptosis in U266 human myeloma cell line]

Statins have been used successfully in the treatment of hypercholesteremia. Moreover, in vitro studies have shown that statins can trigger apoptosis in a variety of tumor cell lines. In the present study we analysed the effect of mevastatin -- a novel inhibitor of HMG-COA reductase, the rate-limiting enzyme of the mevalonate pathway -- on U266 human myeloma cells. Apoptosis induced by mevastatin was associated with increased caspase activity and depolarisation of mitochondrial membrane. Expression of BCL-2 mRNA and protein was down-regulated, with no change in BAX or BCLxL protein production. The mitochondrial program was supported by caspase-8 and cleaved BID activity. None of the antibodies neutralising death-ligand/death-receptor pathway -- TRAIL-R2Fc, anti-TNF-a, anti FASL (NOK-1) -- influenced the mevastatin-induced apoptosis. Mevastatin also stimulated shedding of syndecan-1 from the surface of myeloma cells.

In vitroandin vivoantitumor effect of 2-methoxyestradiol on human melanoma

2-methoxyestradiol (2ME(2)) is an endogenous metabolite of estradiol with estrogen-receptor-independent antitumor and antiangiogenic activity. We examined the effects of 2ME(2) on the cellular proliferation of 8 human melanoma cell lines. We show that 2ME(2) inhibited cell proliferation by inducing apoptosis and an arrest in the G(2)/M phase, and the mechanism of action involved microtubules, mitochondrial damage and caspase activation. In male SCID mice, 2ME(2) was effective in reducing primary tumor weight and the number of liver metastases after intrasplenic injection of human melanoma cells. In the metastases, we found a significantly higher rate of apoptotic cells after 2ME(2) treatment. These findings on the antitumor effect of 2ME(2) in cell culture as well as in an animal model may have implications for designing alternative treatment options for patients with advanced malignant melanoma.

Mevastatin-induced apoptosis and growth suppression in U266 myeloma cells

Statins have been used successfully in the treatment of hypercholesterinaemia. Moreover, in vitro studies have shown that statins can trigger apoptosis in a variety of tumor cell lines. In the present study we analysed the effect of mevastatin--a novel inhibitor of HMG-COA reductase, the rate-limiting enzyme of the mevalonate pathway--on U266 human myeloma cells. Apoptosis induced by mevastatin was associated with increased caspase activity and depolarisation of the mitochondrial membrane. Expression of Bcl-2 mRNA and protein was down-regulated, with no change in Bax or Bcl-XL protein production. The mitochondrial program was supported by caspase-8 and cleaved-Bid activity. None of the antibodies neutralizing the death-ligand/death-receptor pathway--TRAIL-R2Fc, anti-TNF-alpha, anti-FASL(NOK-1)--influenced the mevastatin-induced apoptosis. Mevastatin also stimulated shedding of syndecan-1 from the surface of myeloma cells. The apoptosis inducing effect of mevastatin could be considered as a potential participant in a complex antitumor protocol.

TGF beta 1 induces caspase-dependent but death-receptor independent apoptosis in lymphoid cells

Transforming growth factor beta 1 (TGF beta 1) is an antiproliferative and proapoptotic cytokine for normal B-cells, however many B-cell lymphomas have lost their response to TGF beta 1. The aim of this study was to identify the sequence of events in apoptosis induced by TGF beta 1 in an EBV negative, human B-cell lymphoma line (HT58). The proportion of apoptotic cells increased gradually (up to 72 hr) at an optimal dose range of 0.5-1.0 ng/ml. The induced cell death required the action of downstream caspases. Caspase activation was accompanied by an increase in the permeability of mitochondrial membranes, but there was no change in the expression of certain members of Bcl-2 family (Bcl-2, Bax, Bcl-XL). Similarly, none of the death receptors or ligands were involved in apoptosis induction. Further study will include the participation of TGF beta 1 target genes in the pore formation of mitochondrial membranes and/or the elimination of a putative survival signal.