Search

Acute promyelocytic leukemia is a subtype of acute myeloid leukemia, characterized by the presence of neoplastic promyelocytes, due to the reciprocal balanced translocation between chromosomes 15 and 17. Currently, with the use of agents that act directly on this molecular change, such as all-trans retinoic acid and arsenic trioxide, APL has shifted from a highly mortal to a curable disease. However, some cases are still at high risk of death, especially early death, and acquiring a better understanding of the clinical and biological factors involving APL is needed to correctly identify and treat such cases. The early suspected diagnosis and prompt initiation of the target therapy are important for better response rates. The follow-up and outcomes, using real-life data from 44 consecutive APL patients, were studied between 2001 and 2013. The overall survival rate was 82.7% and early death was 16%. Almost all patient deaths were due to severe bleeding, which was confirmed by multivariate analysis, as the most important prognostic factor leading to death. A better understanding the pathogenesis of the hemorrhagic complications in APL is needed, as well as the risk factors associated with early death in APL patients, as this has become synonymous with overall mortality.

The present study investigated the effects of perinatal exposure to glyphosate-based herbicide (GBH) on liver of immature Wistar rats. Female rats were exposed to GBH (70 mg glyphosate/Kg body weight/day) in drinking water from gestation day 5 and continually up to lactation day 15. The perinatal exposure to GBH increased 45Ca2+ influx in offspring’s liver Pharmacological tools indicated a role played by oxidative stress, phospholipase C (PLC) and Akt pathways, as well as voltage-dependent Ca2+ channel modulation to GBH-induced Ca2+ influx in liver. In addition, changes in the enzymatic antioxidant defense system, decreased GSH content, lipid peroxidation and protein carbonylation suggest a connection between GBH hepatotoxic mechanism and redox imbalance. The perinatal exposure to GBH also increased the enzymatic activities of transaminases and gamma-glutamyl transferase in offspring's liver and blood, suggesting a pesticide-induced liver injury. Moreover, we detected increased iron levels in liver, blood and bone marrow of GBH-exposed rats, which were accompanied by increased transferrin saturation and decreased transferrin levels in blood. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were increased in the liver of rats exposed to GBH. We also detected increased phospho-p65NFκB immunocontent, corresponding to the active form of this transcription factor. Therefore, we propose that excessive amounts of iron induced by perinatal exposure to GBH in offspring’s liver, blood and bone marrow may account for iron-driven hepatotoxicity, which was associated with Ca2+ influx, oxidative damage and inflammation in immature rats. Further studies will clarify whether these events can ultimately impact on liver function.

Pyrazoline is an important 5-membered nitrogen heterocycle that has been extensively researched. Ten derivatives were synthesized and tested for antileukemic effects on 2 human acute leukemia cell lines, K562 and Jurkat. The most cytotoxic of these derivatives, compound 21, was chosen for investigation of cytotoxicity mechanisms. The results obtained with selectivity calculations revealed that compound 21 is more selective for acute leukemia (K562 and Jurkat cell lines) than for other tumor cell lines. Moreover, compound 21 was not cytotoxic to normal cell lines, indicating a potential use in clinical tests. Compound 21 caused a significant cell cycle arrest in the S-phase in Jurkat cells and increased the proportion of cells in the sub G0/G1 phase in both cell lines. Cells treated with compound 21 demonstrated morphological changes characteristic of apoptosis in the EB/AO assay, confirmed by externalization of phosphatidylserine by the annexin V – fluorescein isothiocyanate method and by DNA fragmentation. An investigation of cytotoxicity mechanisms suggests the involvement of an intrinsic apoptosis pathway due to mitochondrial damage and an increase in the ratio of mitochondrial Bax/Bcl2. Pyrazoline 21 obeyed Lipinski’s “rule of five” for drug-likeness. Based on these preliminary results, the antileukemic activity of compound 21 makes it a potential anticancer agent.

Cyclic imides are known for their antitumor activity, especially the naphthalimide derivatives, such as Mitonafide and Amonafide. Recently, we have demonstrated the cytotoxic effect of a series of naphthalimide derivatives against B16F10 melanoma cells. On the basis of this fact, we have developed a study starting from the synthesis of different cyclic imides and the evaluation of their cytotoxic properties on human acute leukemia cells (K562 and Jurkat). Initially, a screening test was conducted to select the compound with the best cytotoxic effect, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. After this selection, structural modifications were performed in the most active compound to obtain five more derivatives. All compounds presented a good cytotoxic effect. The results of cell cycle analysis, fluorescence microscopy, and Annexin V-FITC assay confirmed that the cells observed in the sub-G0/G1 phase were undergoing apoptosis. From this set of results, cyclic imides 8, 10, and 12 were selected for the evaluation of the mechanisms involved in the apoptotic process. The results demonstrate the involvement of the intrinsic pathway of apoptosis, evidenced by the reduction in mitochondrial potential, an increase in the level of AIF protein expression, a decreased level of expression of anti-apoptotic Bcl-2 protein, and an increased level of expression of pro-apoptotic protein Bax in both K562 and Jurkat cells treated with cyclic imides (8, 10, and 12). Furthermore, cyclic imides 8 and 10 caused an increase in the level of Fas expression in Jurkat cells, indicating the additional involvement of the extrinsic apoptosis pathway. The compounds (8, 10, and 12) also caused a decreased level of expression of anti-apoptotic protein survivin. The biological effects observed with these cyclic imide derivatives in this study suggest promising applications against acute leukemia.

Acute leukemia is a disorder of the hematopoietic system characterized by the expansion of a clonal population of cells blocked from differentiating into mature cells. Recent studies have shown that chalcones and their derivatives induce apoptosis in different cell lines. Since new compounds with biological activity are needed, the aim of this study was to evaluate the cytotoxic effect of three synthetic chalcones, derived from 1-naphthaldehyde and 2-naphthaldehyde, on human acute myeloid leukemia K562 cells and on human acute lymphoblastic leukemia Jurkat cells. Based on the results, the most cytotoxic compound (A1) was chosen for further analysis in six human acute leukemia cells and in a human colon adenocarcinoma cell line (HT-29). Chalcone A1 significantly reduced the cell viability of K562, Jurkat, Kasumi, U937, CEM and NB4 cells in a concentration and time-dependent manner when compared with the control group (IC50 values between ∼1.5 μM and 40 μM). It was also cytotoxic to HL-29 cells. To further examine its effect on normal cells, peripheral blood lymphocytes collected from healthy volunteers were incubated with the compound. It has also been incubated with human fibroblasts cultured from bone marrow (JMA). Chalcone A1 is non-cytotoxic to PBL cells and to JMA cells. A1 caused significant cell cycle arrest in all phases according to the cell line, and increased the proportion of cells in the sub G0/G1 phase. To evaluate whether this chalcone induced cell death via an apoptotic or necrotic pathway, cell morphology was examined using fluorescence microscopy. Cells treated with A1 at IC50 demonstrated the morphological characteristic of apoptosis, such as chromatin condensation and formation of apoptotic bodies. Apoptosis was confirmed by externalization of phosphatidylserine, which was detected by the Annexin V-FITC method, and by DNA fragmentation. The results suggest that chalcone A1 has potential as a new lead compound for cancer therapy.

We have previously reported the cytotoxic effects of chalcone A1, derived from 1-naphthaldehyde, in leukemia cell lines. On the basis of these findings, the main aim of this study was to elucidate some of the molecular mechanisms involved in apoptosis induced by chalcone A1 toward K562 and Jurkat cells. In both cell lines, chalcone A1 decreased the mitochondrial membrane potential, increased the expression of Bax proapoptotic protein, and decreased the expression of Bcl-2 antiapoptotic protein (resulting in the inversion of the Bcl-2/Bax ratio), which indicates the involvement of the intrinsic pathway. In addition, chalcone A1 increased the expression of FasR in Jurkat cells, which also indicates the involvement of the extrinsic pathway in this cell line. The results also showed an increased expression of effector caspase-3 and cleaved PARP-1 and a decreased expression of IAP protein survivin, which are consistent with apoptotic cell death. The decreased expression of Ki67 suggests that the mechanism involved in cell death induced by chalcone A1 also involves a decrease in cell proliferation. In ex-vivo experiments, chalcone A1 reduced the cell viability of blast cells collected from eight patients with different types of acute leukemia, confirming the cytotoxicity results found in vitro. The results obtained so far are very promising and further studies need to be carried out so that chalcone A1 can be used as a prototype for the development of new antileukemia agents.

BACKGROUND: According to the 2008 World Health Organization classification, mature B-cell neoplasms are a heterogeneous group of diseases that include B-cell lymphomas and plasma cell disorders. These neoplasms can have very different clinical behaviors, from highly aggressive to indolent, and therefore require diverse treatment strategies. OBJECTIVE: The aim of this study was to assess the profile of 93 patients diagnosed with mature B-cell neoplasms monitored between 2011 and 2014. METHODS: A review of patients' charts was performed and laboratory results were obtained using the online system of the Universidade Federal de Santa Catarina. RESULTS: The study included 93 adult patients with mature B-cell neoplasms. The most frequent subtypes were multiple myeloma, chronic lymphocytic leukemia, diffuse large B-cell lymphoma, follicular lymphoma, and Burkitt's lymphoma. The median age at diagnosis was 58 years with a male-to-female ratio of 1.3:1. There were statistical differences in terms of age at diagnosis, lactate dehydrogenase activity and Ki-67 expression among the subtypes of B-cell lymphoma. According to the prognostic indexes, the majority of multiple myeloma patients were categorized as high risk, while the majority of chronic lymphocytic leukemia patients were classified as low risk. CONCLUSIONS: This study demonstrates the profile of patients diagnosed with mature B-cell neoplasms in a south Brazilian university hospital. Of the B-cell lymphoma, Burkitt's lymphoma presented particular features regarding lactate dehydrogenase activity levels, Ki-67 expression, age at diagnosis, and human immunodeficiency virus infection.

ObjectivesThe aim of the present study was to assess the expression profile of multidrug resistance (MDR)-related proteins ABCB1, ABCC1 and LRP in 46 patients with acute leukemia (AL).MethodsThe levels of MDR gene mRNA expression and protein expression at diagnosis were analyzed by semi-quantitative PCR and flow cytometry, respectively.ResultsIn the adult group, higher expression levels of abcc1 gene were associated with older age and lower levels of lactate dehydrogenase (LDH). In the pediatric group, abcc1 gene expression levels were associated with higher CD34 expression and a higher ABCB1 protein expression was correlated with high WBC counts.Discussion/ConclusionThe present data indicate that abcb1 gene overexpression may be associated with a poor prognosis in adults with AL and that ABCB1 and abcc1 expression correlates with different prognostic factors in pediatric patients with AL. Our findings demonstrate that the method of choice to evaluate chemotherapy resistance-related proteins is a ...

Objectives New compounds with biological targets and less cytotoxicity to normal cells are necessary for cancer therapy. In this work ten synthetic chalcones derived from 2-naphtaldehyde were evaluated for their cytotoxic effect in murine acute lymphoblastic leukemia cells L-1210. Methods A series of ten chalcones derived from 2-naphtaldehyde and corresponding acetophenones were prepared by aldolic condensation, using methanol as solvent under basic conditions, at room temperature for 24 h. The cell viability was determined by MTT colorimeter method. The cell cycle phase analysis was carried out by flow cytometry after propidium iodide staining. The apoptosis induction was assessed by exposure to phosphatidylserine (ANNEXIN V-FITC). Cytometric analysis was performed to evaluate the expression of p53, Bcl-2 and Bax protein. The caspase-3 expression was studied by immunoblotting analysis. Key findings A preliminary screening of a series of ten chalcones derived from 2-naphtaldehyde showed that chalcone 8, (2E)-3-(2-naphtyl)-1-(3′-methoxy-4′-hydroxy-phenyl)-2-propen-1-one, had the highest cytotoxic effect (IC50 of 54 µm), but not in normal human lymphocytes. To better understand the cytotoxic mechanism of chalcone 8, its effect on cell cycle and apoptosis was assessed. Our results showed that chalcone 8 caused cell cycle arrest in the G2/M phase and a significant increase in the proportion of cells in the subG0/G1 phase. Our results also demonstrated that chalcone 8 promoted a modification in Bax : Bcl-2 ratio and increased p53 expression and caspase-3 activation. Conclusions The studied chalcone 8 has cytotoxic effect against L-1210 lymphoblastic leukaemic cells, and this effect is associated with increase of p-53 and Bax expression.

NO (nitric oxide) donating drugs have been investigated for their important role in the sensitization of neoplastic cells to chemotherapy drugs. The goal of this work was to investigate the involvement of NO in the resistance of K562 cells to DNR (daunorubicin). Only simultaneous addition of DNR and SNAP (S-nitroso-N-acetyl-dl-penicillamine) caused significant cell death by apoptosis. Combination of the compounds decreased Bcl-2 and survivin, and increased Bax and active-caspase 3 expression. Fluorescence microscope and cytometric analysis showed that DNR and SNAP together caused DNR intracellular accumulation in K562 cells. RT-PCR (reverse transcription-PCR) analysis showed that DNR and SNAP, alone or in association, produced significant decreases in lrp expression. abcc1 gene expression was unaffected by the presence of SNAP, but when treated with DNR there was a small reduction that was intensified by DNR and SNAP in combination. The transport mechanism involved in the resistance to DNR in K562 cells involves ABCC1 and LRP (lung resistance protein) resistance proteins. DNR and SNAP inhibition of the expression of these proteins occurs by distinct mechanisms, and this disrupts the K562 resistance to DNR.

Croton celtidifolius Baill is a tree found in the Atlantic Forest South of Brazil, mainly in Santa Catarina. The bark and leaf infusions of this medicinal plant have been popularly used for the treatment of inflammatory diseases. The anti-aggregant activity of C. celtidifolius crude extract (CE) and the column chromatography (CC) isolated compounds flavonoids, catechin and gallocatechin were evaluated in human blood platelets. The platelet-rich plasma (PRP) was incubated with different concentrations of flavonóides (50 - 200 µg/mL) to be tested before platelet aggregation was induced by the agonists adenosine 5'diphosphate (ADP) and collagen. At 200 µg/mL the CE, catechin and gallocatechin markedly inhibited platelet aggregation with the aggregant agents. Using ATP production as an index of platelet secretory capacity, we observed a decreased production of ATP in platelets treated with flavonoids when stimulated by collagen. On the other hand, the flavonoids did not promote inhibitory effect on prothrombin time (PT), thromboplastin time (APTT) and thrombin time (TT). In conclusion, these observations suggest that C. celtidifolius is likely to exert an inhibitory action on platelets in vitro by suppressing secretion and platelet aggregation. Croton celtidifolius Baill é uma árvore encontrada na Mata Atlântica, no sul do Brasil, principalmente no estado de Santa Catarina. A infusão da casca e folhas dessa planta medicinal é utilizada na medicina popular para o tratamento de doenças inflamatórias. A atividade antiagregante do extrato bruto de C. celtidifolius (CE) e de seus flavonóides isolados por coluna cromatográfica (CC), catequina e galocatequina, foi avaliada em plaquetas humanas. O plasma rico em plaquetas (PRP) foi incubado com diferentes concentrações dos flavonóides testados (50 - 200 µg/mL) e posteriormente a agregação foi induzida pelos agonistas adenosina 5'difosfato (ADP) e colágeno. Na concentração de 200 µg/mL o CE, a catequina e a galocatequina inibiram a agregação plaquetária induzida pelos agonistas. A produção de ATP foi utilizada como um índice de capacidade de secreção plaquetária e observamos uma diminuição na produção de ATP nas plaquetas tratadas com os flavonóides e estimuladas com o colágeno. Por outro lado, os flavonóides não promoveram um efeito inibitório no tempo de protrombina (PT), tempo de tromboplastina parcial ativada (APTT) e tempo de trombina (TT). Essas observações sugerem que o C. celtidifolius exerce, in vitro, uma ação inibitória nas plaquetas através da inibição da secreção e agregação plaquetária.