Cytotoxic effects and apoptosis induction of atrazine in a grass carp (Ctenopharyngodon idellus) cell line

Atrazine is a widely used herbicide that was considered to be an endocrine disrupter capable of interfering with the synthesis and action of natural hormones. In the present study, we found that atrazine was able to cause apoptosis in grass carp (Ctenopharyngodon idellus) cells from cell line ZC7901. By fluorescent and transmission electron microscopy, the atrazine-incubated cells displayed a series of morphological changes, including condensation of the nucleus, margination of chromatin to form dense granular caps, and formation of apoptotic bodies. Moreover, DNA fragmentation was detected by the TUNEL reaction and agarose gel electrophoresis. These typical characteristics of cells undergoing apoptosis indicated the occurrence of apoptosis in ZC7901. Apoptosis induced by atrazine was dose- and time-dependent and was involved in mitochondrial membrane potential (DeltaPsi(m)) disruption, elevation in intracellular Ca(2+), generation of reactive oxygen species, and intracellular ATP depletion. This study provides the first evidence that atrazine was able to induce apoptosis in fish cells, which indicated the existence of a novel cytotoxic mechanism caused by atrazine and may improve our understanding of the complex relationship between contaminants and aquatic organisms.     

Protection of T cells from radiation-induced apoptosis by Cepharanthin®

Cepharanthin (CE) is a medicine that contains several biscoclaurine alkaloids. We examined the effects of CE on radiation-induced T cell apoptosis. Radiation induced apoptosis on T cells in a dose-dependent manner, while CE inhibited radiation-induced apoptosis. CE also attenuated the cytotoxic effects of radiation on the proliferative response of T cells. CE inhibited not only the loss of mitochondrial transmembrane potential but also the activation of caspase 3 in irradiated T cells. Radiation plus CE induced the up-regulation of Bax and the down-regulation of Bcl-2 in T cells in comparison with radiation alone. These results suggest that CE inhibits the signal transduction pathway of apoptosis induced by radiation, regardless of the expression of Bcl-2 or Bax.     

Induction of HepG2 cell apoptosis by Irgarol 1051 through mitochondrial dysfunction and oxidative stresses

In this study, HepG2 cells were exposed to 0.04–40 mg/L Irgarol 1051. Results show that Irgarol 1051 can damage cell morphology and cause a significant decrease in cell viability. Positive staining by Annexin V, caspase-3 activity enhancement, and the damage in cell ultrastructure indicated an apoptotic mode of cell death for 4.0 mg/L Irgarol 1051 treatment. At the same time, caspase-9 was also significantly induced by 0.4 and 4.0 mg/L Irgarol 1051 at 72 h, which suggests that the intrinsic mitochondria pathway was involved in the apoptosis. The mitochondrial membrane potential decreased significantly after the HepG2 cells were exposed to Irgarol 1051 for 6 and 72 h. Especially, the translocation of cytochrome c from mitochondria to cytosol was recorded, supporting the idea that the mitochondrial pathway was involved in the apoptosis signal pathways induced by Irgarol 1051. The significantly increased levels of intracellular reactive oxygen species (ROS) and an immediate ROS burst were also recorded. The results here may imply that Irgarol 1051 induces HepG2 cell apoptosis through mitochondrial dysfunction and oxidative stresses. Although it is possible that this chemical has no detrimental effects on human health at the environmentally relevant concentration, it may cause problems to top coastal predators due to bio-accumulation through the food chain.     

rBTI induces apoptosis in human solid tumor cell lines by loss in mitochondrial transmembrane potential and caspase activation

The molecular mechanisms and the possible effects of a recombinant buckwheat trypsin inhibitor (rBTI) on the induction of apoptosis in the human solid tumor cells (EC9706, HepG2 and HeLa) were investigated. An MTT assay showed that rBTI could specifically inhibit the growth of solid tumor cells in a dose- and time-dependent manner. Analysis by flow cytometry indicated that the apoptosis of several tumor cells increased after treatment with rBTI in range of 6.25–50 μg/ml. DNA electrophoresis analysis showed the ‘DNA ladder’, typical of apoptosis. rBTI-induced apoptosis was shown to involve Bax and Bak up-regulation, Bcl-2 and Bcl-xl down-regulation, release of cytochrome c from the mitochondria to the cytosol, activation of caspase-3 and -9 and disruption of the mitochondrial transmembrane potential (Δψ_m). The z-DEVD-fmk caspase-3 inhibitor significantly inhibited rBTI-induced apoptosis. We concluded that rBTI can induce the apoptosis in several types of human solid tumor cells and promotes apoptosis through the mitochondrial apoptotic pathway.     

Iso-suillin from the mushroom Suillus flavus induces cell cycle arrest and apoptosis in K562 cell line

Iso-suillin, an isomer of suillin that belongs to the prenylphenol class of fungal derivatives, was isolated from petroleum ether extracts of Suillus flavus. The IC₅₀ value of iso-suillin in K562 cells was 0.87 μM, which was lower than the positive control cisplatin (19.33 μM). Iso-suillin-treated K562 cells exhibited an increased rate of apoptosis, mitochondrial membrane potential (MMP) depolarization, and G0/G1 arrest. Western blot analysis revealed that these cells displayed significantly upregulated expression of several apoptosis-related proteins, including cytochrome c, caspase 9, FADD (Fas-associating protein with a novel death domain), caspase 8, caspase 3, and Bax. Moreover, the expression of two anti-apoptosis proteins, NF-κB and Bcl-2, was downregulated. Inhibitors of caspase 9 and caspase 8 protected the K562 cells from apoptosis. Taken together, our results suggest that iso-suillin induces K562 apoptosis through the mitochondrial and death receptor pathways and that iso-suillin may represent a candidate anti-leukemia treatment.     

Silica nanoparticles induced intrinsic apoptosis in neuroblastoma SH-SY5Y cells via CytC/Apaf-1 pathway

The present study was to investigate effects of Silica nanoparticles (SiNPs) on nervous system and explore potential mechanisms in human neuroblastoma cells (SH-SY5Y). Cytotoxicity was detected by cell viability and Lactate dehydrogenase (LDH) release. Flow cytometry analysis was applied to assess mitochondrial membrane potential (MMP) loss, intracellular Ca²⁺ and apoptosis. To clarify the mechanism of SiNPs-induced apoptosis, intrinsic apoptosis-related proteins were detected. Our results showed that SiNPs caused cytotoxicity, cell membrane damage and Ca²⁺ increase in a dose-dependent manner in SH-SY5Y cells. Both the mitochondrial membrane potential (MMP) loss and potential mitochondria damage resulted in Cyt C release to the cytoplasm. The elevated Cyt C and Apaf1 further triggered intrinsic apoptosis via executive molecular caspase-9 and caspase-3. The present study confirmed that SiNPs induced intrinsic apoptosis in neuroblastoma SH-SY5Y cells via CytC/Apaf-1 pathway and provided a better understanding of the potential toxicity induced by SiNPs on human neurocyte.     

神经酰胺诱导结肠癌HT-29细胞凋亡与线粒体膜电位变化的关系

目的 探索神经酰胺(C2-ceramide,C2-cer)对人结肠癌HT-29细胞增殖、线粒体膜电位改变、细胞凋亡等的影响.方法 正常培养的HT-29细胞分为C2-cer处理组与非处理组,用MTT法、流式细胞仪等方法观察不同时间C2-cer对细胞增殖、线粒体膜电位改变、细胞凋亡等的影响.结果 加入C2-cer可引起HT-29细胞线粒体膜电位 (△Ψm)下降,细胞增殖受抑,并导致细胞凋亡.上述效应与C2-cer剂量以及作用时间相关.结论 C2-cer可导致HT-29细胞线粒体膜电位(△Ψm)下降,抑制细胞增殖,诱导细胞凋亡.     

Protective effect of metoclopramide against organophosphate‐induced apoptosis in the murine skin fibroblast L929

This study was performed to evaluate the protective efficacy of metoclopramide (MCP) against the organophosphates paraoxon (POX)‐ and malathion (MLT)‐induced apoptosis in the murine L929 skin fibroblasts. L929 cells were exposed to either POX (10 nm ) or 1.0 μm MLT in the absence and presence of increased concentrations of MCP. The protective effect of MCP on these organophosphate‐stimulated apoptotic events was evaluated by flow cytometry analysis after staining with annexin‐V/propidium iodide, processing and activation of the executioner caspase‐3, cleavage of the poly‐ADP ribose polymerase, fragmentation of the nucleosomal DNA and disruption of the mitochondrial membrane potential (Δψ). Our results showed that increased doses of MCP alone (≥10 μm ) did not induce apoptosis or activation of caspase‐3. Pretreatment of the cells with MCP attenuated all the apoptotic events triggered by the organophosphate compounds in a dose‐dependent manner reaching ~70–80% protection when they were preincubated at 1 and 5 μm of the drug before the addition of POX and MLT, respectively. Interestingly, MCP did not offer a significant protective effect against the cytotoxicity of tumor necrosis factor‐α, cisplatinum, etoposide or paclitaxel, which stimulate apoptosis by various mechanisms, suggesting that the anti‐apoptotic effect of the drug is specific to organophosphates. The strong and specific anti‐apoptotic activity of subclinical doses of MCP against the cytotoxicity of organophosphate compounds suggests its potential clinical application in treating their poisoning.     

Condurango glycoside-rich components stimulate DNA damage-induced cell cycle arrest and ROS-mediated caspase-3 dependent apoptosis through inhibition of cell-proliferation in lung cancer,in vitro and in vivo

Chemotherapeutic potential of Condurango glycoside-rich components (CGS) was evaluated in NSCLC, in vitro and in BaP-intoxicated rats, in vivo. NSCLC cells were treated with different concentrations of CGS to test their effect on cell viability. Cellular morphology, DNA-damage, AnnexinV-FITC/PI, cell cycle regulation, ROS-accumulation, MMP, and expressions of related signalling genes were critically analysed. 0.22 μg/μl CGS (IC₅₀ dose at 24 h) was selected for the study. CGS-induced apoptosis via DNA damage was evidenced by DNA-ladder formation, increase of AnnexinV-positive cells, cell cycle arrest at subG0/G1 and differential expressions of apoptotic genes_. ROS-elevation and MMP-depolarization with significant caspase-3 activation might lead to apoptotic cell death. Anti-proliferative activity was confirmed by EGFR-expression modulation. ROS accumulation and DNA-nick formation with tissue damage-repair activity after post-cancerous CGS treatment, in vivo, supported the in vitro findings. Overall results advocate considerable apoptosis-inducing potential of CGS against NSCLC, validating its use against lung cancer by CAM practitioners.     

Scorpion venom (Odontobuthus doriae) induces apoptosis by depolarization of mitochondria and reduces S-phase population in human breast cancer cells (MCF-7)

Venom of some species of scorpions induces apoptosis and arrests proliferation in cancer cells. This is an important property that can be harnessed and can lead to isolation of compounds of therapeutic importance in cancer research. Cytotoxicity was investigated using MTT reduction and confirmed with lactate dehydrogenase release following venom exposure. Apoptosis was evaluated with determination of mitochondrial membrane potential, reactive nitrogen species assay, measurement of Caspase-3 activity and DNA fragmentation analysis. To confirm that venom can inhibit DNA synthesis in proliferating breast cancer cells, immunocytochemical detection of BrdU incorporation was done. Our results demonstrated that venom of Odontobuthus doriae not only induced apoptosis but lead to the inhibition of DNA synthesis in human breast cancer cells (MCF-7). Cell viability decreased with parallel increment of LDH release in dose dependent manner after treatment with varying concentrations of venom. Moreover, venom depleted cellular antioxidants evidenced by depression of GSH and Catalases and concomitantly increased reactive nitrogen intermediates (RNI). These events were related to the depolarization of mitochondria and associated Caspase-3 activation following venom treatment in a concentration dependent manner. Finally, fragmentation of nuclear DNA following venom treatment confirmed the apoptotic property of the said venom. These results suggest that venom of O. doriae can be potential source for the isolation of effective anti-proliferative and apoptotic molecules.     

Anti-benzopyrene-7,8-diol-9,10-epoxide induces apoptosis via mitochondrial pathway in human bronchiolar epithelium cells independent of the mitochondria permeability transition pore

Anti-benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) is a ubiquitous environmental pollutant contained in tobacco smoke, automobile exhausts and barbecued foods. The carcinogenicity of BPDE on animals has been well characterized, whereas its apoptotic effect is not well defined. A recent study has shown that BPDE-mediated apoptotic pathway has varying specificity across different cell lines. Squamous cell carcinoma (SCC) arises from bronchiolar epithelium cells, therefore, we set out to investigate the pulmonary toxicity and apoptotic effect of BPDE in human bronchiolar epithelium cells (16HBE). Our results show BPDE induces mitochondrial-mediated apoptosis in a dose-dependent manner in 16HBE cells. The cleavage of caspase-3,-9 and release of Cytochrome c (cyt c) was regulated during apoptotic stimulation. However, the opening of mitochondria permeability transition pore (mPTP) has not been detected. Furthermore, our data also indicate that the formation of reactive oxygen species (ROS), decline of mitochondrial membrane potential (ΔΨ_m), increasing p53 and decreasing c-Myc levels play important roles in response to BPDE toxicity. In conclusion, these results suggest that BPDE-mediated apoptosis occurs via caspase-9 dependent mitochondria pathway associated with ROS formation, loss of ΔΨ_m, up-regulation of p53 and down-regulation of c-Myc, but independent of the opening of mPTP in 16HBE cells.     

Induction of G2/M arrest and apoptosis by sesquiterpene lactones in human melanoma cell lines

Malignant melanoma is a highly aggressive tumor which frequently resists chemotherapy, therefore, the search for new agents for its treatment is of great importance. In this study, we purified the sesquiterpene lactones (SLs), Tomentosin and Inuviscolide from Inula viscosa (Compositae) leaves and studied their anti-cancer potency against human melanoma cell lines in order to develop new agents for melanoma treatment. SLs inhibited the proliferation of three human melanoma cell lines: SK-28, 624 mel and 1363 mel in a dose-dependent manner. We further investigated SLs mechanism of action using SK-28 as a representative cell line model. SLs caused cell-cycle arrest at G(2)/M, accompanied by the appearance of a sub-G0 fraction, indicative of apoptotic cell death. Induction of apoptosis was further confirmed by changes in membrane phospholipids, changes in mitochondrial membrane potential (DeltaPsi) and by detection of Caspase-3 activity. Rapid inhibitory phosphorylation of Cdc2 (Thr14 and Tyr15) was seen early after treatment, followed by a later decrease in the expression level of both Cyclin b1 and Cdc2. Induction of p53 and p21(waf1) proteins and phosphorylation of p53 at Ser15 were also detected early after treatment. The anti-apoptotic proteins, p65 subunit of nuclear factor kappaB (NF-kappaB), and Survivin were reduced in a dose-dependent manner. Taken together, these changes partially explain the ability of the SLs to induce G(2)/M arrest and apoptosis. Induction of apoptosis by Tomentosin and Inuviscolide in human aggressive melanoma cell lines has high pharmacological value and implies that SLs might be developed as new agents for melanoma treatment.     

Induction of apoptosis in two human leukemia cell lines as well as differentiation in human promyelocytic cells by cyanidin-3-O-beta-glucopyranoside

Little is known about the potentially chemopreventive mechanisms of anthocyanins apart from their antioxidant activity. We investigated the in vitro capacity of the anthocyanin cyanidin-3-O-beta-glucopyranoside (Cy-g) to induce apoptosis in T-lymphoblastoid, as well as apoptosis and differentiation in HL-60 promyelocytic cells. Although Cy-g-induced apoptosis (as well as necrosis) in the two systems, HL-60 cells were much less sensitive than T-lymphoblastoid cells. Moreover, treatment of HL-60 cells with Cy-g caused differentiation into macrophage-like cells and granulocytes. Concerning the mechanism of action, the induction of apoptosis in Jurkat T cells can be explained by a modulation of p53 and bax protein expression. At the molecular level, the induction of apoptosis and cytodifferentiation in HL-60 cells involved different proteins, thus suggesting that the effects of Cy-g on apoptosis and cytodifferentiation induction are two distinct events. These interesting biological properties should encourage further investigation into the chemopreventive and/or chemotherapeutic potential of Cy-g.     

Adenosine induces apoptosis in the human gastric cancer cells via an intrinsic pathway relevant to activation of AMP-activated protein kinase

Extracellular adenosine significantly reduced cell viability in a dose (0.1-20mM)- and treatment time (24-72h)-dependent manner in GT3-TKB cells, a human gastric cancer cell line. Nuclei of cells were reactive to Hoechst 33342, a marker of apoptosis, and an anti-single-stranded DNA. Adenosine-induced GT3-TKB cell death was significantly inhibited by dipyridamole, an inhibitor of adenosine transporter, and 5'-amino-5'-deoxyadenosine, an inhibitor of adenosine kinase, but the effect was not affected by theophylline, a broad inhibitor of adenosine receptors, 8-cyclopentyltheophylline, an inhibitor of A(1) adenosine receptors or 3,7-dimethyl-1-propargylxanthine, an inhibitor of A(2a) adenosine receptors. Adenosine had no effect on mitochondrial membrane potentials. The effect of adenosine on GT3-TKB cell death was not inhibited by a pancaspase inhibitor or inhibitors of caspase-1,-3,-4,-8, and -9. 5-Aminoimidazole-4-carboxamide ribonucleoside (AICAR), an activator of AMP-activated protein kinase (AMPK), significantly reduced GT3-TKB cell viability, but the AICAR action was not reinforced in the presence of adenosine. The results of the present study, thus, suggest that extracellular adenosine induces apoptosis in GT3-TKB cells by its uptake into cells and conversion to AMP followed by activation of AMPK, regardless of caspase activation linked to the mitochondria and the endoplasmic reticulum.     

Induction of apoptosis by cinobufacini preparation through mitochondria- and Fas-mediated caspase-dependent pathways in human hepatocellular carcinoma cells

Cinobufacini (Huachansu), an aqueous extract from the skins of Bufo bufo gargarizans Cantor, is a well-known traditional Chinese medicine widely used in clinical cancer therapy in China. However, the precise mechanisms induced by cinobufacini in human hepatocellular carcinoma (HCC) cells are still not very clear. The aim of present study was to investigate possible apoptotic mechanisms induced by cinobufacini in HCC cell lines HepG(2) and Bel-7402. We found that cinobufacini treatment resulted in a significant decrease in cell proliferation and induced apoptotic cell death with the increase of treatment time. It indicated that cinobufacini-induced apoptosis was associated with mitochondria-mediated pathway including the loss of mitochondrial membrane potential (Δψm), the increase of Bax/Bcl-2 ratio, cytochrome c release, caspase-9 and caspase-3 activation, and poly(ADP-ribose) polymerase (PARP) degradation. Additionally, cinobufacini also activated Fas-mediated apoptosis pathway obviously as evident by an increase in Fas expression, and caspase-8 and caspase-10 activation. Moreover, the BH3-only protein Bid was cleaved into a truncated Bid (tBid) after cinobufacini treatment. Taken together, these data suggested cinobufacini could induce apoptosis of HCC cells through mitochondria- and Fas-mediated caspase-dependent pathways with the increase of treatment time, which might provide an experimental evidence for cinobufacini treatment of HCC.     

Cadmium induces apoptotic cell death in WI 38 cells via caspase-dependent Bid cleavage and calpain-mediated mitochondrial Bax cleavage by Bcl-2-independent pathway

Previous reports have demonstrated that cadmium (Cd) may induce cell death via apoptosis, but the mechanism responsible for cellular death is not clear. In this study, we investigated the signaling pathways implicated in Cd-induced apoptosis in lung epithelial fibroblast (WI 38) cells. Apoptotic features were observed using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, propidium iodide staining and DNA laddering. A treatment of cadmium caused the caspase-8-dependent Bid cleavage, the release of cytochrome c (Cyt c), activation of caspase-9 and -3, and PARP cleavage. A caspase-8 specific inhibitor prevented the Bid cleavage, caspase-3 activation and cell death. Alternatively, we observed that full-length Bax was cleaved into 18-kDa fragment (p18/Bax); this was initiated after 12 h and by 36 h the full-length Bax protein was totally cleaved to the p18/Bax, which caused a drastic release of Cyt c from mitochondria. The p18/Bax was detected exclusively in the mitochondrial fraction, and it originated from mitochondrial full-length Bax, but not from the cytosol full-length Bax. Cd also induced the activation of the mitochondrial 30-kDa small subunit of calpain that was preceded by Bax cleavage. Cd induced the upregulation of Bcl-2 and the degradation of p53 protein. N-acetyl cysteine effectively inhibited the Cd-induced DeltaPsim reduction, indicating ROS acts upstream of mitochondrial membrane depolarization. Taken together, our results suggest that Cd-induced apoptosis was thought to be mediated at least two pathways; caspase-dependent Bid cleavage, and the other is calpain-mediated mitochondrial Bax cleavage. Moreover, we found that the function of Bid and Bax was not dependent of Bcl-2, and that ROS can also contribute in the Cd-induced cell death.     

Pharmacological and biochemical characterization of the beta-adrenergic signal transduction pathway in different segments of the respiratory tract

Although in the respiratory system there is great therapeutic interest in manipulating and understanding the beta-adrenoceptor-G-protein-adenylate cyclase (AC) signal transduction pathway, little is known on segmental differences among lung, bronchus, and trachea with regard to the receptor concentration and interaction to G-proteins and coupling to AC. In this study, patterns of distribution and absolute quantities of beta-adrenoceptor subtypes beta(1) and beta(2) were determined in membranes of equine lung parenchyma, bronchial and tracheal epithelium with the underlying smooth muscle by saturation and competition binding assays using the radioligand (-)-[125I]-iodocyanopindolol (ICYP). Additionally, the functional coupling of beta-adrenoceptors to G-proteins (assessed by beta-agonist competition binding in the presence and absence of GTP) as well as the coupling efficiency and biochemical activities of AC was investigated in each region. The specific ICYP binding was rapid, reversible, saturable with time and of high affinity. The radioligand binding identified more total beta-adrenoceptors in the lung than in bronchus or trachea (428+/-19, 162.4+/-4.8, 75.6+/-1.2 fmol/mg protein, respectively) with about 40% of receptors in the high affinity state. The beta(2)-adrenoceptor subtype predominated in all segments (approximately 74-80%), as the highly selective beta(2)-adrenoceptor antagonist ICI 118,551 was about 10,000 times more potent in inhibiting ICYP binding than was the beta(1)-selective adrenoceptor antagonist CGP 20712A, and beta-adrenoceptor agonists inhibited ICYP binding with an order of potency: (-)-isoprenaline>(-)-adrenaline>(-)-noradrenaline. The dissociation constant (K(d)) was higher in the trachea than in bronchus or lung (13.0+/-0.9 pM vs. 20.0+/-2.3 pM vs. 30.8+/-4.4 pM, P<0.05, respectively). The beta(2)-adrenoceptor-mediated AC response was tissue-dependent; stimulants acting on beta-adrenoceptor (isoproterenol), G-protein (GTP, NaF) and AC (forskolin, Mn(2+)) enhanced AC responses in all three regions, but the AC activity was higher in tracheal crude membranes than in bronchus or lung (trachea>bronchus>lung), hence, the number of beta(2)-adrenoceptors correlated inversely with the amount of AC. We conclude that (1) the stoichiometry of components within the pulmonary beta-adrenoceptor-G-protein complex is segment-dependent, and (2) the receptor number or AC activity is possibly the rate-limiting factor in the beta-adrenoceptor-G-protein-AC-mediated physiological responses. Thus, it is speculated that this could have important therapeutic consequences in beta-adrenoceptor agonist-induced receptor regulation in bronchial asthma.     

Induction of apoptosis by cordycepin via reactive oxygen species generation in human leukemia cells

Cordycepin (3′-deoxyadenosin), a specific polyadenylation inhibitor, is the main functional component in Cordyceps militaris, one of the top three renowned traditional Chinese medicines. Cordycepin has been shown to possess many pharmacological activities including immunological stimulation, and anti-bacterial, anti-viral, and anti-tumor effects. However, the mechanisms underlying its anti-cancer mechanisms are not yet understood. In this study, the apoptotic effects of cordycepin were investigated in human leukemia cells. Treatment with cordycepin significantly inhibited cell growth in a concentration-dependent manner by inducing apoptosis but not necrosis. This induction was associated with generation of reactive oxygen species (ROS), mitochondrial dysfunction, activation of caspases, and cleavage of poly(ADP-ribose) polymerase protein. However, apoptosis induced by cordycepin was attenuated by caspase inhibitors, indicating an important role for caspases in cordycepin responses. Administration of N-acetyl-l-cysteine, a scavenger of ROS, also significantly inhibited cordycepin-induced apoptosis and activation of caspases. These results support a mechanism whereby cordycepin induces apoptosis of human leukemia cells through a signaling cascade involving a ROS-mediated caspase pathway.     

Increase of mesenchymal stem cell migration by cannabidiol via activation of p42/44 MAPK

Migration and differentiation of mesenchymal stem cells (MSCs) are known to be involved in various regenerative processes such as bone healing. However, little is known about the pharmacotherapeutical options aiming at the mobilization and differentiation of MSCs. The present study therefore focussed on cannabinoids which have been demonstrated to exhibit tissue healing properties. Using Boyden chamber assays, the non-psychoactive phytocannabinoid cannabidiol (CBD) was found to increase the migration of adipose-derived MSCs in a time- and concentration-dependent manner. CBD-induced migration was inhibited by AM-630 (CB₂ receptor antagonist) and O-1602 (G protein-coupled receptor 55 [GRP55] agonist). Moreover, the promigratory effect of CBD was antagonized by inhibition of the p42/44 mitogen-activated protein kinase (MAPK) pathway which became activated upon CBD treatment. In line with this data, AM-630 and O-1602 attenuated CBD-induced p42/44 MAPK phosphorylation. A p42/44 MAPK-dependent promigratory effect was likewise demonstrated for the GPR55 antagonist O-1918 and the selective CB₂ receptor agonist JWH-133. Additional evidence for a functional effect of CBD on MSCs was provided by experiments demonstrating long-term stimulation with CBD to induce differentiation of MSCs into the osteoblastic lineage as evidenced by increased mineralization assessed by cresolphthalein complexone assay and enhanced activity of alkaline phosphatase. Collectively, this study demonstrates CBD to promote the migration of MSCs via activation of the CB₂ receptor and inhibition of GPR55 and to induce osteoblastic differentiation. CBD may therefore recruit MSCs to sites of calcifying tissue regeneration and subsequently support bone regeneration via an osteoanabolic action on MSCs.