Berberine induces apoptosis through a mitochondrial/caspase pathway in human promonocytic U937 cells

Berberine, an isoquinoline plant alkaloid, is known to generate a wide variety of biochemical and pharmacological effects. To elucidate the molecular mechanism of berberine-induced antiproliferative activities, the human promonocytic U937 cells were used. Berberine exhibited dose-dependent antiproliferative effects. Morphological evidence of apoptosis, including apoptotic DNA fragmentation, were observed in cells treated with 75 microg ml(-1) of berberine for 24h. Flow cytometry analysis revealed that berberine had no effect on cell cycle profile of U937 cells, however, sub-G(0) fraction (apoptotic cell population) was detected. The percentage of sub-G(0) fraction of cells treated with 75 microg ml(-1) of berberine was 25.3+/-1.6%. Berberine induces significant changes in mitochondrial membrane potential of U937 cells. The highest tested concentration of berberine decreased the mitochondrial membrane potential to 15.8+/-2.4% of control. Additionally, berberine-treated cells had an elevated level of ROS production. Activation of caspase-9 and caspase-3 was also detected, with no caspase-8 activation observed. Taken together, the results clearly demonstrate that berberine induces apoptosis of U937 cells through the mitochondrial/caspase-dependent pathway.

Carvacrol and rosemary essential oil manifest cytotoxic, DNA-protective and pro-apoptotic effect having no effect on DNA repair

For several thousand years natural products were successfully used to treat a variety of diseases and to maintain health in humans, but until now it is not fully known what causes these medicinal effects. In our study we assessed the cytotoxic, DNA-protective and pro-apoptotic effect of two frequently occurring natural compounds, carvacrol and rosemary essential oil, on human hepatoma HepG2 cells. In addition we examined the in vitro incision repair activity of liver cell extracts prepared from hepatocytes isolated from Sprague-Dawley (SD) rats fed with water containing carvacrol or rosemary oil. Using conventional and modified single cell gel electrophoresis we proved that incubation of HepG2 cells with selected concentrations of carvacrol and rosemary oil significantly protected cellular DNA against two dangerous oxidative agents, hydrogen peroxide (H(2)O(2)) and 2,3-dimethoxy-1,4-naphthoquinone (DMNQ). It is interesting that despite this DNA protection, the addition of both volatiles to the drinking water of SD rats had no effect on incision repair capacity of hepatocyte extracts. In this paper we also showed that carvacrol and rosemary oil can trigger apoptotic cell death pathways in HepG2 cells, which is probably connected with their cytotoxicity.

Synthesis and Anticancer Activity of Novel 9-O-Substituted Berberine Derivatives

Berberine is a bioactive isoquinoline alkaloid derived from many plants. Although berberine has been shown to inhibit growth and induce apoptosis of several tumor cell lines, its poor absorption and moderate activity hamper its full therapeutic potential. Here, we describe the synthesis of a series of 9-O-substituted berberine derivatives with improved antiproliferative and apoptosis-inducing activities. An analysis of novel berberine derivatives by EPR spectroscopy confirmed their similar photosensitivity and analogous behavior upon UVA irradiation as berberine, supporting their potential to generate ROS. Improved antitumor activity of novel berberine derivatives was revealed by MTT assay, by flow cytometry and by detection of apoptotic DNA fragmentation and caspase-3 activation, respectively. We showed that novel berberine derivatives are potent inhibitors of growth of HeLa and HL-60 tumor cell lines with IC₅₀ values ranging from 0.7 to 16.7 µM for HL-60 cells and 36 to >200 µM for HeLa cells after 48 h treatment. Further cell cycle analysis showed that the observed inhibition of growth of HL-60 cells treated with berberine derivatives was due to arresting these cells in the G₂/M and S phases. Most strikingly, we found that berberine derivative 3 (9-(3-bromopropoxy)-10-methoxy-5,6-dihydro-[1,3]dioxolo[4,5-g]isoquino[3,2-a] isoquinolin-7-ylium bromide) possesses 30-fold superior antiproliferative activity with an IC₅₀ value of 0.7 µM and 6-fold higher apoptosis-inducing activity in HL-60 leukemia cells compared to berberine. Therefore, further studies are merited of the antitumor activity in leukemia cells of this berberine derivative.

Cytotoxic effects of plant extracts from the families Fabaceae, Oleaceae, Philadelphaceae, Rosaceae and Staphyleaceae

A human transformed line of HeLa cells was treated with extracts prepared from Gymnocladus dioicus, Holodiscus discolor, Stephanandra tanakae, Ligustrum delavayanum, Ligustrum vulgare and Staphylea pinnata. The study evaluating the influence of the active extracts on HeLa cell division also reveals their acute, delayed and combined effect. A 35% degradation of HeLa cells was found after 72 h treatment with 62.5 microg/mL of the extract isolated from Stephanandra tanakae. A 100% lysis of HeLa cells was observed after 72 h treatment with a 125 microg/mL concentration of the extract prepared from Gymnocladus dioicus. The extracts from Ligustrum devayanum and Ligustrum vulgare were specifically effective only with HeLa cells. On the other hand, the extract prepared from Gymnocladus dioicus was effective on the bacteria and on the HeLa cells.

3-(5-Nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline induces ROS-mitochondrial mediated death signaling and activation of p38 MAPK in murine L1210 leukemia cells

Quinazoline derivatives are multitarget agents with a broad spectrum of biological activity. 3-(5-nitro-2-thienyl)-9-chloro-5-morpholin-4-yl[1,2,4]triazolo[4,3-c]quinazoline (NTCHMTQ) is a new synthetically prepared derivative, which in our previous studies showed antiproliferative and apoptosis inducing activities towards murine L1210 leukemia cells. The aim of this study was to provide the insight into the molecular mechanism regulating NTCHMTQ-induced apoptosis in L1210 cells. The activity of caspases 3, 8 and 9, generation of reactive oxygen species (ROS), mitochondrial membrane potential changes, release of cytochrome c, degradation of PARP and activation of c-Jun N-terminal kinase 1/2 (JNK1/2), p38 MAPK and extracellular-regulated kinase 1/2 (ERK1/2) were investigated. NTCHMTQ induced production of ROS, activation of caspases 3 and 9, cytochrome c release, PARP cleavage and activation of p38 MAPK, with no activation of JNK1/2 and ERK1/2. Our resuls clearly demonstrate that NTCHMTQ induces apoptosis of L1210 leukemia cells through ROS-mitochondrial mediated death signaling and activation of p38 MAPK.

Cytotoxicity of hydroxyapatite, fluorapatite and fluor-hydroxyapatite: a comparative in vitro study

The purpose of this study was to evaluate the cytotoxicity of two formulations of hydroxyapatite (HA), namely fluorapatite (FA) and fluor-hydroxyapatite (FHA). HA is used as carrier material for antibiotics or anticancer drugs during treatment of bone metastasis. Negative control, represented by HA, was included for comparative purposes. Leukemia cells were used as a model cell line, and the effect of eluates of tested biomaterials on cell proliferation/viability and mechanism of antiproliferative activity were assessed. Study design attempted to reveal the toxicity of tested biomaterials with an emphasis to decide if tested biomaterials have promise for further studies in vivo. Results showed that eluates of FA and FHA inhibit the growth of leukemia cells and induce programmed cell death through mitochondrial/caspase-9/caspase-3-dependent pathway. Due to these differences compare to HA, it is concluded that FA and FHA have promise for evaluation of their behaviour in vivo.

New [1,2,4]triazolo[4,3-c]quinazoline enhances cisplatin- and temozolomide-induced growth inhibition and apoptosis in HL-60 cells

The purpose of this study was to investigate the therapeutic potential of a newly synthesized [1,2,4]triazolo[4,3-c]quinazoline (NTCHMTQ) alone and in combination with two anticancer drugs (cisplatin and temozolomide) against HL-60 leukemia cell line. The IC50 value of NTCHMTQ toward HL-60 cells was 19.7 microM. No apoptosis and cell cycle changes were observed in cells treated with 5 microM NTCHMTQ alone. Combination of non-toxic concentrations of NTCHMTQ (1-5 microM) with cisplatin or temozolomide sensitized HL-60 cells to these two drugs and significantly enhanced their efficacies, that is illustrated by combination indexes, sub-G0 cell fraction, apoptotic DNA fragmentation and caspase-3 activity. The results suggest that combined therapy of non-toxic concentrations of NTCHMTQ with chemotherapeutics may provide synergistic regimen for treatment of leukemia. However, further in vitro and in vivo experimental drug-cell and drug-drug studies are warranted.

Antiproliferative activity and apoptosis induced by 6-bromo-2-(morpholin-1-yl)-4-anilinoquinazoline on cells of leukemia lines

Quinazolines are known to be multitarget agents with broad spectrum of biological activity.

AIM

To investigate anticancer activity of newly prepared 6-bromo-2-(morpholin-1-yl)-4-anilinoquinazoline (BMAQ) towards L1210, HL-60 and U-937 leukemia cells.

MATERIALS AND METHODS

Growth inhibition of BMAQ-treated cells was determined by cell counting using trypan blue staining technique. Apoptosis and cell cycle profile changes were analysed using internucleosomal DNA fragmentation assay, fluorescence microscopy and flow cytometry. Activity of caspase-3 was determined using colorimetric method.

RESULTS

Cell proliferation assay showed that BMAQ caused significant decrease of cell number in a dose-dependent manner. BMAQ induced cell death by apoptosis, based on results from DNA fragmentation, fluorescence microscopy and caspase-3 assays.

CONCLUSION

Presented results clearly demonstrate that BMAQ is a promising anticancer agent with significant antiproliferative and apoptotic activities towards leukemia cells in vitro.

Growth inhibition and apoptosis induced by 2-phenoxymethyl-3H-quinazolin-4-one in HL-60 leukemia cells

AIM

The aim of the study was to investigate anticancer activity of newly synthesized 2-phenoxymethyl-3H-quinazolin-4-one (PMQ).

MATERIALS AND METHODS

Anticancer activity of PMQ was studied towards human HL-60 leukemia cells. Antiproliferative activity of PMQ was determined by direct counting of cells using trypan blue staining technique. Apoptosis and cell cycle profile changes were analysed using internucleosomal DNA fragmentation assay and flow cytometry. Activation of caspases and changes in glutathione level were monitored using colorimetric or luminiscent methods.

RESULTS

PMQ induced concentration-dependent cytotoxicity in leukemia cells, with IC(50) of 10.8 +/- 0.9 microM. DNA flow cytometry analysis and DNA ladder formation assay indicated that PMQ actively induced apoptosis of cells accompanied by a block of cells in G(2)/M phase and a marked loss of cells in G(0)/G(1) and S phases. Additionally, the activities of caspase-3 and caspase-9 were increased significantly and a markedly increased level of oxidized glutahione was observed. Inhibition of glutahione synthesis using buthionine sulfoximine sensitized leukemia cells to PMQ, confirming the involvement of ROS in PMQ-induced apoptosis.

CONCLUSION

The results of this study clearly demonstrate that PMQ is a promising anticancer drug showing cytostatic and apoptotic effects toward HL-60 leukemia cells mainly through mitochondrial/caspase-9 dependent pathway.