Molecular events and cytotoxic effects of a novel thiosemicarbazone derivative in human leukemia and lymphoma cell lines.

The present study aimed to investigate the cytotoxic effect of 38 new thiosemicarbazone derivatives on hematological neoplastic cells lines and to select the most effective compounds to investigate the main molecular mechanisms involved in cell death. Cytotoxicity screening on Daudi and Jurkat cells revealed that only compound 1b met the selection criteria; therefore, it was chosen for further investigation. Cell viability of Daudi, Jurkat, Molt-4, Namalwa, K562, and MM.1S cell lines decreased in a concentration- and time-dependent manner after compound1b incubation; nevertheless the compound neither caused significant hemolysis nor reduction in peripheral blood mononuclear cell viability. Although no changes were observed on cell cycle or Ki-67 expression, compound1b induced apoptotic-like cell death with mitochondrial involvement, Bax/Bcl-2 inversion, AIF release, survivin inhibition, and caspase-3 activation in both Daudi and Jurkat cells. Furthermore, the compound reduced NFκB expression in Jurkat cells. In Daudi cells, compound1b also decreased CHOP, Akt, pAkt, and MAPK/ERK2 expression, thereby suggesting modulation of UPR, PI3K/Akt/mTOR, and MAPK/ERK signaling pathways. Finally, the compound was able to reduce the cell viability of samples collected from patients with different lymphoid neoplasms subtypes, showing that thiosemicarbazones derivatives could be used in the development of new drugs with anticancer activity.

Apoptotic events induced by a natural plastoquinone from the marine alga Desmarestia menziesii in lymphoid neoplasms.

There exists an urgent need for the development of new drugs for the treatment of lymphoid neoplasms. The aim of this study was to evaluate the cytotoxic effect of the marine plastoquinone 9'-hydroxysargaquinone (9'-HSQ), focusing on investigation of the mechanism by which it causes death in lymphoid neoplastic cells. This particular plastoquinone reduced the cell viability of different hematological tumor cell lines in a time-dependent and concentration-dependent manner. Intrinsic apoptosis occurred with time-dependent reduction of mitochondrial membrane potential (42.3 ± 1.1% of Daudi cells and 18.6 ± 5.6% of Jurkat cells maintained mitochondrial membrane integrity) and apoptosis-inducing factor release (Daudi: 133.3 ± 8.1%, Jurkat: 125.7 ± 6.9%). Extrinsic apoptosis also occurred, as reflected by increased FasR expression (Daudi: 139.5 ± 7.1%, Jurkat: 126.0 ± 1.0%). Decreases were observed in the expression of Ki-67 proliferation marker (Daudi: 67.5 ± 2.5%, Jurkat: 84.3 ± 3.8%), survivin (Daudi: 66.0 ± 9.9%, Jurkat: 63.1 ± 6.0%), and NF-κB (0.7 ± 0.04% in Jurkat cells). Finally, 9'-HSQ was cytotoxic to neoplastic cells from patients with different lymphoid neoplasms (IC50: 4.9 ± 0.6 to 34.2 ± 0.4 µmol/L). These results provide new information on the apoptotic mechanisms of 9'-HSQ and suggest that it might be a promising alternative for the treatment of lymphoid neoplasms.

Synthesis of novel pyrazoline derivatives and the evaluation of death mechanisms involved in their antileukemic activity.

Malignant neoplasms are one of the leading causes of death worldwide and hematologic malignancies, including acute leukemia (AL) is one of the most relevant cancer types. Current available chemotherapeutics are associated with high morbidity and mortality rates, therefore, the search for new molecules with antitumor activity, specific and selective for neoplastic cells, became a great challenge for researchers in the oncology field. As pyrazolines stand out in the literature for their great variety of biological activities, the aim of this study was to synthesize and evaluate the antileukemic activity of five new pyrazoline derivatives. All pyrazolines showed adequate physicochemical properties for a good oral bioavailability. The two unpublished and most effective pyrazoline derivatives have been selected for further experiments. These compounds are highly selective for leukemic cells when compared to non-neoplastic cells and did not cause lysis on human red blood cells. Additionally, selected pyrazolines induced cell cycle arrest at G0/G1 phase and decreased cell proliferation marker KI67. Apoptotic cell death induced by selected pyrazolines was confirmed by morphological analysis, assessment of phosphatidylserine residue exposure and DNA fragmentation. Several factors indicate that both intrinsic and extrinsic apoptosis occurred. These were: increased FasR expression; the predominance of Bax in relation to Bcl-2; the loss of mitochondrial membrane potential; AIF release; decreased expression of survivin (an antiapoptotic protein); and the activation of caspase-3. The selected pyrazolines were also found to be cytotoxic against neoplastic cells collected from the peripheral blood and bone marrow of patients with different subtypes of acute leukemia.

MICONIDINE acetate, a new selective and cytotoxic compound with synergic potential, induces cell cycle arrest and apoptosis in leukemia cells.

Plants are important sources of biologically active compounds and they provide unlimited opportunities for the discovery and development of new drug leads, including new chemotherapeutics. Miconidin acetate (MA) is a hydroquinone derivative isolated from E. hiemalis. In this study we demonstrated that MA was cytotoxic against acute leukemia (AL), solid tumor cells and cancer stem cells, with the strongest effect exhibited against AL. Furthermore, it was non-cytotoxic against non-tumor cells and did not cause significant hemolysis. MA blocks the G2/M phase and causes cytostatic effects, acting in a similar way to dexamethasone by increasing PML expression. The compound also triggered intrinsic and extrinsic apoptosis by modulating Bax, FasR and survivin expression. This led to an extensive mitochondrial damage that resulted in AIF, cytochrome c and endonuclease G release, caspase-3 and PARP cleavage and DNA fragmentation. We have further demonstrated that MA was strongly cytotoxic against neoplastic cells collected from patients with different AL subtypes. Interestingly, MA increased the cytotoxic effect of chemotherapeutics cytarabine and vincristine. This study indicates that MA may be a new agent for AL and highlights its potential as a new source of anticancer drugs. Graphical abstract MA blocks G2/M phase with PML expression and KI67 inhibition, ROS generation and intrinsic and extrinsic apoptosis, leading to mitochondrial damage, caspase 3 and PARP cleavage and DNA fragmentation.

Cytotoxic effect of a novel naphthylchalcone against multiple cancer cells focusing on hematologic malignancies.

Chalcones are natural compounds described in the literature by its several properties including cytotoxic activity against several tumor types. Considering that the search for new chemotherapeutic agents is still necessary, the aim of this study was to investigate the cytotoxic mechanisms involved in cell death induced by a synthetic chalcone (A23) on different tumor cells. Chalcone A23 reduced the cell viability of twelve tumor cell lines in a concentration and time dependent manner and it was more cytotoxic against acute leukemia cells. Interestingly, the compound was non cytotoxic to normal cells and non-hemolytic to normal red blood cells. Chalcone A23 decreased the expression of cell proliferation marker KI-67 and blocked the G2/M phase in both K562 and Jurkat cell lines. Cells treated with A23 showed morphological features suggestive of apoptosis, the "latter pattern" in agarose gel, the externalization of phosphatidylserine and caspase-3 and PARP cleavage. Chalcone A23 significantly reduced the mitochondrial membrane potential, decreased the expression of anti-apoptotic proteins Bcl-2 and survivin and increased the expression of pro-apoptotic protein Bax, confirming the involvement of the intrinsic pathway. The increased mitochondrial permeability resulted in the release of AIF, cytochrome c and endonuclease G from the mitochondria to the cytosol. In addition, chalcone A23 increased the expression of FasR and induced Bid cleavage, showing the involvement of the extrinsic pathway. Finally, chalcone A23 seems to have a synergic effect with the chemotherapy drugs cytarabine and vincristine. These results suggest that A23 is an interesting compound with strong and selective anti-tumor activity.

Oral Delivery of a High Quercetin Payload Nanosized Emulsion: In Vitro and In Vivo Activity Against B16-F10 Melanoma.

Quercetin is a natural compound that has several biological activities including anticancer activity. However, the use of this drug has been limited mostly because of its poor water solubility and low bioavailability. Therefore, the development of quercetin-loaded nanocarrier systems may be considered a promising advance to exploit its therapeutic properties in clinical setting including cancer treatment. This study evaluates the effect of orally administered nanosized emulsion containing quercetin (QU-NE) on the cytotoxicity activity against B16-F10 cells in vitro, and on subcutaneous melanoma in mice inoculated with B16-F1O cells. In vivo experiments, also evaluate the co-administration of quercetin with cisplatin in order to predict synergic effects and the renal and hepatic toxicity. The nanocarriers were prepared through the hot solvent diffusion associated with the phase inversion temperature methods. In vitro study showed reduction of cell viability in a concentration-depend manner for free quercetin and QU-NE. In vivo study, quercetin either as a free drug or colloidal dispersion was administrated at a dose of 5 mg kg(-1) twice a week for 17 days via oral route. Cisplatin was administrated at dose of 1 mg kg(-1) once a week intraperitoneally. Free quercetin and QU-NE reduced tumor growth, however, the reduction observed for QU-NE (P < 0.001 vs. control) was significantly higher than free quercetin (P < 0.05 vs. control). The association of both drugs did not show synergic effect. Besides, no renal or hepatic toxicities were observed after administration of free quercetin and QU-NE. These results suggest that an improvement in the oral bioavailability of quercetin occurred when this compound was dissolved in the oily phase of a nanosized emulsion, indicating that it might have a potential application in the treatment of melanoma.

Investigation of cellular mechanisms involved in apoptosis induced by a synthetic naphthylchalcone in acute leukemia cell lines.

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.

Continuous and intermittent running to exhaustion at maximal lactate steady state: neuromuscular, biochemical and endocrinal responses.

OBJECTIVE: The aim of the present study was to characterize the neuromuscular, biochemical, and endocrinal responses from a running to exhaustion mode at the maximal lactate steady state intensity during continuous and intermittent protocols. DESIGN: Pre-post test measures. METHODS: Twelve athletes performed an incremental treadmill test, several constant speed tests to determine the maximal lactate steady state at continuous and intermittent (5:1 ratio) models and two randomized tests until exhaustion at such intensities. Knee extension torque and blood sampling were collected before and immediately after the time to exhaustion tests. RESULTS: The results showed a significant decrement (∼15%) in torque production after time to exhaustion tests for both exercise models. In addition to neuromuscular impairment, an acute increase of 65% and 38% was observed creatine kinase, during continuous and intermittent running, respectively. Regarding hormonal responses when compared to baseline measurements, cortisol increased by 132% and 121% in the continuous and intermittent protocols, respectively. No correlation was found between biochemical, endocrinal and the neuromuscular variables. CONCLUSIONS: The present findings showed that running until exhaustion performed at maximal lactate steady state, significantly impaired muscle strength and increased hormonal and muscle damage markers in two different protocols (i.e. continuous and intermittent) amongst trained runners.

Apoptotic events induced by synthetic naphthylchalcones in human acute leukemia cell lines.

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.