• 한국식품영양과학회지
• /
• 제45권6호
• /
• pp.835-842
• /
• 2016

PI3K/Akt 신호계는 세포 생존의 조절에 필수적인 경로로 대부분 암세포에서 활성이 증대되어 있다. 본 연구에서는 동충하초의 주요 생리활성 물질인 cordycepin에 의한 AGS 인체 위암 세포의 apoptosis 유도에 미치는 PI3K/Akt 신호계의 역할을 조사하였다. 본 연구의 결과에 의하면 cordycepin의 처리 농도의 증가에 따라 AGS 세포의 생존율은 억제되었으며, 이는 apoptosis 유도와 밀접한 관계가 있음을 핵의 형태적 변화와 flow cytometry 분석을 통하여 확인 하였다. 이러한 cordycepin의 apoptosis 유도 효과는 PI3K/Akt 신호계의 활성 저하와 연관성이 있었으며, 세포독성을 나타내지 않는 범위의 PI3K/Akt 신호계 저해제인 LY294002를 cordycepin과 동시 처리하였을 경우, cordycepin에 의한 apoptosis 유발을 더욱 증대시켰다. 그리고 cordycepin에 대한 LY294002의 apoptosis 유발 증대는 caspases (caspase-3, -8 및 -9)의 활성 증가와 poly(ADP-ribose) polymerase 단백질의 분해 증가를 촉진했다. 또한 cordycepin이 처리된 AGS 세포에서 LY294002는 apoptosis 유도에 관여하는 Bax의 발현을 증가시켰고 apoptosis 억제에 관여하는 Bcl-2의 발현은 감소시켰으며, 이는 미토콘드리아 기능 손상과 미토콘드리아에서 세포질로의 cytochrome c 유리를 증대시켰다. 따라서 PI3K/Akt 신호계의 활성 차단은 cordycepin의 항암 활성을 더욱 상승시켰으며, 이는 미토콘드리아 기능 손상과 caspase의 활성 증대를 통하여 이루어짐을 알 수 있었다.

• Clinical and Experimental Reproductive Medicine
• /
• 제26권3호
• /
• pp.419-432
• /
• 1999

Objective: To establish the evaluation system of the quality of oocytes on the basis of the incidence of cumulus cells apoptosis, to investigate the relationships beween the incidence of cumulus cells and the outcomes of IVF-ET. Method: Thirth-four cycles undergoing controlled ovarian hyperstimulation for IVF-ET with tubal infertility (23 cycles) or unexplained infertility (11 cycles) were included in this study. Cumulus cell masses surrounding mature oocyte and co-culture of embryos with autologous cumulus cells during IVF-ET process. The incidence of apoptosis in cumulus cells was assessed by apoptosis detection kit fluorescein. The effect of co-culture using cumulus cells and the incidence of cumulus cells apoptosis. Results: The results were as follows: 1. The incidence of apoptosis in cumulus cells markedly increased in patients aged 40 or over, while the fertilization rate was greatly decreased in those age group. 2. Apoptosis in cumulus cells was found in both the fertilized oocytes and unfertilized oocytes, but the incidence of apoptosis was higher in unfertilized oocytes. 3. There is no clear correlation between apoptosis in cumulus cells and the number of oocytes retrieved. However, the incidence of apoptosis was increased when the number of oocytes retrieved was 5 and fewer in comparison with $6{\sim}10$. 4. Embryo grade was significantly affected by the incidence of apoptosis in cumulus cells. 5. Pregnancy rate of IVF-ET per cycle was 29.4%, and the pregnant group had the higher fertilization rate and a significantly lower incidence of apoptosis in cumulus cells compared with the nonpregnant group. 6. When cumulus cells were used as helper cells in the co-culture of the embryo, in vitro activity of cumulus cells based on morphological change and proliferation did not influence the quality of embryo, but was closely associated with the implantation rate and pregnancy rate, which was enhanced when morphological changes and proliferation of cumulus cells was more active. 7. This difference in the outcome of IVF-ET according to in vitro activity of cumulus cells used for co-cultue was not associated with the incidence of apoptosis in cumulus cells; but rather had likely relations with the different secretion pattern of protein, which may be an embryo trophic factor by cumulus cells. Conclusion: These results suggest that the incidence of apoptosis in cumulus cells can be used in predicting oocyte qualities and the outcomes of IVF-ET. And the effect of co-culture largely depends on the in vitro activity of cumulus cells as well.

• Parasites, Hosts and Diseases
• /
• 제38권1호
• /
• pp.17-23
• /
• 2000

Eosinophils are important effector cells in host defense against parasites. Excretory-secretory product (ESP) produced by helminthic worms plays important roles in the uptake of nutrients, migration in the host tissue, and in immune modulation. However little is known about the ability of the ESP to directly trigger eosinophil apoptosis. This study investigated whether the ESP of newly excysted metacercariae of Paragonimus westermani could induce apoptosis in human eosinophils. Apoptosis was assayed by staining the cells with FITC-annexin V, and the cells were analyzed by flow cytometry. It was found that the ESP of newly excysted metacercariae of P. westemani induced a direct time- and concentration-dependent increase in the rate of constitutive apoptosis in mature human eosinophils. Eosinophil apoptosis was first apparent 3 hr after treatment with the ESP and continued to increase after 6 hr of incubation with respect to the cells cultured in the absence of the ESP. While only 2.8% of the eosinophils incubated in the medium for 3 hr were apoptotic, 7.6%, 10.9% and 22.6% of the eosinophils treated with 10. 30 and $100{\;}\mu\textrm{g}/ml$ ESP were apoptotic, respectively. This result suggests that the ESP of newly excysted metacercariae of P. westermani directly induce eosinophil apoptosis, which may be important for the survival of the parasites and the reduction of eosinophilic inflammation in vivo.

• Biomolecules & Therapeutics
• /
• 제17권4호
• /
• pp.379-387
• /
• 2009

We have previously reported that N-ethylmaleimide (NEM) induces apoptosis through activation of $K^+$, $Cl^-$-cotransport (KCC) in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of phospholipase $A_2$ ($PLA_2$)-arachidonic acid (AA) signals in the mechanism of the NEM-induced apoptosis. In these experiments we used arachidonyl trifluoromethylketone ($AACOCF_3$), bromoenol lactone (BEL) and p-bromophenacyl bromide (BPB) as inhibitors of the calcium-dependent cytosolic $PLA_2$ ($cPLA_2$), the calcium-independent $PLA_2$ ($iPLA_2$) and the secretory $PLA_2$ ($sPLA_2$), respectively. BEL significantly inhibited the NEM-induced apoptosis, whereas $AACOCF_3$ and BPB did not. NEM increased AA liberation in a dose-dependent manner, which was markedly prevented only by BEL. In addition AA by itself induced $K^+$ efflux, a hallmark of KCC activation, which was comparable to that of NEM. The NEM-induced apoptosis was not significantly altered by treatment with indomethacin (Indo) and nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively. Treatment with AA or 5,8,11,14-eicosatetraynoic acid (ETYA), a non-metabolizable analogue of AA, significantly induced apoptosis. Collectively, these results suggest that AA liberated through activation of $iPLA_2$ may mediate the NEMinduced apoptosis in HepG2 cells.

• Nutrition Research and Practice
• /
• 제4권6호
• /
• pp.455-461
• /
• 2010

The tumor microenvironment, particularly sufficient nutrition and oxygen supply, is important for tumor cell survival. Nutrition deprivation causes cancer cell death. Since apoptosis is a major mechanism of neuronal loss, we explored neuronal apoptosis in various microenvironment conditions employing neuroblastoma (NB) cells. To investigate the effects of tumor malignancy and differentiation on apoptosis, the cells were exposed to poor microenvironments characterized as serum-free, low-glucose, and hypoxia. Incubation of the cells in serum-free and low-glucose environments significantly increased apoptosis in less malignant and more differentiated N-type IMR32 cells, whereas more malignant and less differentiated I-type BE(2)C cells were not affected by those treatments. In contrast, hypoxia (1 % $O_2$) did not affect apoptosis despite cell malignancy. It is suggested that DLK1 constitutes an important stem cell pathway for regulating self-renewal, clonogenicity, and tumorigenicity. This raises questions about the role of DLK1 in the cellular resistance of cancer cells under poor microenvironments, which cancer cells normally encounter. In the present study, DLK1 overexpression resulted in marked protection from apoptosis induced by nutrient deprivation. This in vitro model demonstrated that increasing severity of nutrition deprivation and knock-down of DLK1 caused greater apoptotic death, which could be a useful strategy for targeted therapies in fighting NB as well as for evaluating how nutrient deprived cells respond to therapeutic manipulation.

• BMB Reports
• /
• 제38권6호
• /
• pp.709-716
• /
• 2005

Apoptosis and necrosis are distinguished by modality primarily. Here we show an apoptosis occurred instantly, induced by $300\;{\mu}M$ W-7 ((N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride), inhibitor of calmodulin), which demonstrated necrotic modality. As early as 30 min after W-7 addition, apoptotic (sub-diploid) peak could be detected by fluorescence-activated cell sorter (FACS), “DNA ladders” began to emerge also at this time point, activity of caspase-3 elevated obviously within this period. Absence of mitochondrial membrane potential (MMP) reduction and cytochrome c, AIF (apoptosis inducing factor) release, verified that this rapid apoptosis did not proceed through mitochondria pathway. Activation of caspase-12 and changes of other endoplasmic reticulum (ER) located proteins ascertained that ER pathway mediated this necrosis-like apoptosis. Our findings suggest that it is not credible to judge apoptosis by modality. Elucidation of ER pathway is helpful to comprehend the pathology of diseases associated with ER stress, and may offer a new approach to the therapy of cancer and neurodegenerative diseases.

• The Korean Journal of Physiology and Pharmacology
• /
• 제1권1호
• /
• pp.107-115
• /
• 1997

We studied the effects of bile acids on the induction ofapoptosis in HepG2 human hepatocellular carcinoma cells. Treatment with either ursodeoxycholic acid (UDCA) or lithocholic acid (LCA) resulted in a dose- and time-dependent decrease in cell viability assessed by MTT assay. Both UDCA and LCA also induced genomic DNA fragmentation, a hallmark of apoptosis, indicating that the mechanism by which these bile acids induce cell death was through apoptosis. Cycloheximide, a protein synthesis inhibitor, blocked the apoptosis induced by these bile acids, implying that new protein synthesis may be required for the apoptosis. Intracellular $Ca^{2+}$ release blockers (dantrolene and 3,4,5-trimethoxybenzoic acid-8-(diethylamino)octyl ester) inhibited decreased cell viability and DNA fragmentation induced by these bile acids. Treatment of HepG2 cells with calcium ionophore A23l87 induced DNA fragmentation. These results suggest that UDCA and LCA induce apoptosis in the HepG2 cells and that the activation of intracellular $Ca^{2+}$ signals may play an important role in the apoptosis induced by these bile acids.

• Asian Pacific Journal of Cancer Prevention
• /
• 제15권22호
• /
• pp.9593-9597
• /
• 2014

Ursolic acid, extracted from the traditional Chinese medicine bearberry, can induce apoptosis of gastric cancer cells. However, its pro-apoptotic mechanism still needs further investigation. More and more evidence demonstrates that mitochondrial translocation of cofilin-1 appears necessary for the regulation of apoptosis. Here, we report that ursolic acid (UA) potently induces the apoptosis of gastric cancer SGC-7901 cells. Further mechanistic studies revealed that the ROCK1/PTEN signaling pathway plays a critical role in UA-mediated mitochondrial translocation of cofilin-1 and apoptosis. These findings imply that induction of apoptosis by ursolic acid stems primarily from the activation of ROCK1 and PTEN, resulting in the translocation of cofilin-1 from cytoplasm to mitochondria, release of cytochrome c, activation of caspase-3 and caspase-9, and finally inducing apoptosis of gastric cancer SGC-7901 cells.

• 대한수의학회지
• /
• 제43권4호
• /
• pp.607-613
• /
• 2003

Dendritic cells (DCs) play an essential role in a variety of immune reactions involving $CD4^+$ T cells and have been used to enhance tumor-specific immune responses. Immunosuppression in patients with cancer includes the downregulation of function and number of DCs. Although DCs have been studied, the apoptosis of Des induced by anticancer drugs for chemotherapy remains largely uncharacterized. This study demonstrated that GM-CSF protects DCs from 5-fluorouracil (5-FU) or mitomycin C-induced apoptosis. After 6 - 10 days culture, DCs were characterized by specific surface marker, CD11c and MHC class II. MTT assay revealed that GM-CSF significantly enhanced the viability of DCs treated with 5-FU or mitomycin C. The percentage of dead cells of DCs was determined by cell size using FACScan and GM-CSF was clearly effective. However, GM-CSF did not increase the expression of MHC class II on viable DCs gated, suggesting that GM-CSF may differentially regulate critical factors involved in the function of DCs. For the quantitative analysis of apoptosis, annexin V-FITC staining was performed. 5-FU induced the apoptosis of DCs and GM-CSF significantly protects DCs from 5-FU-induced apoptosis. Taken together, the results in this study that GM-CSF has an anti-apoptosis effect on DCs may provide patients with cancer with clinical benefits to overcome the immunosuppression induced by the decrease of number and functional insufficiency of DCs.

• 대한의생명과학회지
• /
• 제20권1호
• /
• pp.32-38
• /
• 2014

Potassium cyanate (KOCN) that is known as an inducer of the protein carbamylation is an inorganic compound and is the conjugate based of cyanic acid (HOCN). Based on these studies, we confirmed that KOCN induces the apoptosis of the human colorectal cancer cell line, HCT 116 cells, by various mitochondrial pathways. To investigate other mechanisms of KOCN-mediated apoptosis, in the present study, we examined KOCN-induced cytokines production in HCT 116 cells and identified the intracellular signaling pathway in these processes. We first demonstrated that KOCN considerably increased the cell apoptosis via intracellular $Ca^{2+}$ signaling, mitochondrial dysfunction and ROS production. And then we examined TNF-${\alpha}$ and IL-$1{\beta}$ levels mediated by KOCN in HCT 116 cells. Although IL-$1{\beta}$ was not involved in KOCN-mediated HCT 116 cell apoptosis, the release of TNF-${\alpha}$ was mediated by KOCN in HCT 116 cells via NF-${\kappa}B$ activation. Apoptosis was also enhanced by incubation with supernatants from HCT 116 cells after KOCN treatment and this effect was partially reduced by BAY 11-7085 pre-treated supernatant. Taken together, our results indicate that KOCN-induced apoptosis in HCT 116 cells is dependent on the releases of TNF-${\alpha}$ and the increased factors and that the mechanism involves the activation of NF-${\kappa}B$.