Indomethacin decreases arachidonic acid uptake in HCA-7 human colon cancer cells

Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the incidence of colorectal cancer. However, evidence is accumulating that NSAIDs have anti-cancer effects in addition to inhibiting cyclooxygenase (COX)-mediated prostanoid biosynthesis. We now show that indomethacin, a popular NSAID, significantly reduced the [3H]-arachidonic acid uptake in HCA-7 human colon cancer cells. Interestingly, no decrease in the uptake of [3H]-arachidonic acid occurred when the cells were treated with aspirin, diclofenac, and sulindac even though the concentrations of these NSAIDs were high enough to inhibit COX-2 activity. These findings suggest that indomethacin has a novel anti-cancer effect that may be independent of COX-2 inhibition.     

Aspirin induces apoptosis in YD-8 human oral squamous carcinoma cells through activation of caspases,down-regulation of Mcl-1, and inactivation of ERK-1/2 and AKT

NSAIDs and COX-2 inhibitors show anti-cancer activities in many cancer cells. In this study, we investigated the effects of NSAIDs (aspirin or indomethacin) and COX-2 inhibitor (NS-398) on growth of YD-8 human oral squamous carcinoma cells. Interestingly, among drugs tested, aspirin showed strongest inhibitory effects on viability and survival of YD-8 cells. Profoundly, aspirin treatment resulted in severe cell shrinkage and nuclear DNA fragmentation in YD-8 cells, suggesting the aspirin-induced apoptosis in YD-8 cells. Data of Western blot further demonstrated that aspirin treatment caused activation of caspases, down-regulation of Mcl-1 protein, dephosphorylation of ERK-1/2 and AKT, and also IκB-α proteolysis-dependent NF-κB activation in YD-8 cells. Aspirin, however, had no effect on expressions of Bcl-2, XIAP, and HIAP-1 in YD-8 cells. Importantly, pretreatment with z-VAD-fmk, a pan-caspase inhibitor blocked the aspirin-induced apoptosis and Mcl-1 down-regulation in YD-8 cells. These findings collectively suggest that aspirin induces apoptosis in YD-8 cells and the induction may be correlated to activation of caspases, caspase-dependent Mcl-1 proteolysis, inactivation of ERK-1/2 and AKT, and activation of NF-κB. It is suggested that aspirin may be applied a potential anti-cancer drug against human oral squamous carcinoma.     

Alantolactone induces activation of apoptosis in human hepatoma cells

Alantolactone, a sesquiterpene lactone, possesses anti-inflammatory property. In this study, we provide evidence that it could be developed as a novel agent against human liver cancer. We observed that alantolactone treatment to HepG2, Bel-7402 and SMMC-7721 cells, human liver cancer cell lines resulted in a dose-dependent inhibition of cell growth. We selected HepG2 cell line as a test model system. Alantolactone treatment of HepG2 cells resulted in a dose-dependent induction of apoptosis and arrest of cells in G2-M phase. This induction of apoptosis seems to be mediated via modulating the protein levels of Bcl-2 family and activation of caspases. Moreover, caspase-8 and Bid activation, loss of mitochondrial transmembrane potential and cytochrome c release suggest the existence of a cross-talk between the death receptor and the mitochondrial pathways. We also observed that alantolactone treatment of cells resulted in a dose-dependent decrease in NF- κB/p65. In addition, a significant and progressive increase in the level of p53 protein in alantolactone-treated cells was observed. Taken together, our data suggest that alantolactone could be developed as an agent against human liver cancer.     

Additive effect of zinc oxide nanoparticles and isoorientin on apoptosis in human hepatoma cell line

Metal nanomaterial could effectively decrease tumour resistance to anti-cancer drugs. In this paper, we have explored the synergistic effect and mechanisms of zinc oxide nanoparticles (ZnO Nps) and isoorientin (ISO) on cytotoxicity in human hepatoma (HepG2) cells. The results showed that ZnO Nps could exert dose- and time-dependent cytotoxicity in HepG2 cells, and the combining treatment resulted in a greater cytotoxicity than single treatment. ZnO Nps could synergistically potentiate ISO to induce apoptosis through resulting in mitochondrial dysfunction, inhibiting the phosphorylation of Akt and ERK1/2, and enhancing the phosphorylation of JNK and P38. Additionally, ZnO Nps were uptaked by cells through endocytic pathway and it enhanced the cellular uptake of ISO, while no significant injury was found in normal liver cells after the combined treatment. These results suggest that the combination of metal nanoparticle with anti-cancer drugs may provide a promising alternative for novel cancer treatments.     

自噬对肝癌HepG2细胞增殖及对细胞周期影响的研究

目的研究用诱导肝癌HepG2细胞自噬与抑制肝癌HepG2细胞自噬的方法检测自噬对肝癌HepG2细胞增殖的影响,阐明细胞自噬的发生与细胞周期的关系。方法常规培养肝癌HepG2细胞,应用MTT比色法和流式细胞仪检测肝癌HepG2细胞增殖抑制率及细胞周期各时相的变化。结果自噬诱导剂雷帕霉素组的肝癌HepG2细胞抑制率明显高于对照组（P〈0.05）,对照组的肝癌HepG2细胞抑制率明显高于自噬抑制剂3-MA组（P〈0.05）;流式细胞仪分析示自噬诱导剂雷帕霉素组细胞周期中G1期细胞增多,S期细胞减少,G2/M期细胞相对增多（P〈0.05）。自噬抑制剂3-MA组细胞周期中G1期细胞减少,S期细胞增多,G2/M期细胞相对减少（P〈0.05）。结论自噬对肝癌HepG2细胞增殖有抑制作用,自噬不利于肝癌HepG2细胞成活。肝癌HepG2细胞自噬的发生多停留在细胞周期的G1期。     

Diclofenac, a non-steroidal anti-inflammatory drug, suppresses apoptosis induced by endoplasmic reticulum stresses by inhibiting caspase signaling

Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used in the treatment of inflammation and pain. In many reports, NSAIDs have induced apoptosis in a variety of cell lines such as colon cancer cells. On the other hand, more recently a few reports have found that NSAIDs protect against apoptosis. Here we investigate endoplasmic reticulum (ER)-stress-induced apoptosis of neuronal cells. The aim of this study is to examine the involvement of NSAIDs, in particular diclofenac, on ER-stress-induced apoptosis of human neuroblastoma SH-SY5Y cells. Diclofenac significantly suppressed SH-SY5Y cell death induced by two types of ER-stress-inducing agents: thapsigargin, an inhibitor of Ca2+-ATPase on the endoplasmic reticulum membrane, and tunicamycin, a glycosylation blocker. Other NSAIDs, such as indomethacin, ibuprofen, aspirin, and ketoprofen, also suppressed ER-stress-induced SH-SY5Y cell death. The dose-dependent anti-apoptotic effect of diclofenac did not correlate with the reduction of prostaglandin release. Administration of prostaglandin E2, which was a primary product of arachidonic metabolism, showed no effects against anti-apoptotic effects produced by diclofenac. Thapsigargin and tunicamycin each significantly activated caspase-3, -9, and -2 in the intrinsic apoptotic pathway in SH-SY5Y cells. Diclofenac suppressed the activation of caspases induced by both ER stresses. Thapsigargin and tunicamycin decreased the mitochondrial membrane potential in SH-SY5Y cells. Diclofenac suppressed the mitochondrial depolarization induced by both ER stresses. Diclofenac inhibited ER-stress-induced apoptosis of SH-SY5Y cells by suppressing the activation of caspases in the intrinsic apoptotic pathway. This is the first report to find that diclofenac has protective effects against ER-stress-induced apoptosis.     

The apoptotic effect of brucine from the seed of Strychnos nux-vomica on human hepatoma cells is mediated via Bcl-2 and Ca2+ involved mitochondrial pathway.

In an attempt to dissect the mechanism of Strychnos nux-vomica, a commonly used Chinese folk medicine in the therapy of liver cancer, the cytotoxic effects of four alkaloids in Strychnos nux-vomica, brucine, brucine N-oxide, strychnine, and isostrychnine, on human hepatoma cells (HepG2) were screened by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrasolium bromide (MTT) assay. Brucine, among the four alkaloids, exhibited the strongest toxic effect, the mechanism of which was found to cause HepG2 cell apoptosis, since brucine caused HepG2 cell shrinkage, the formation of apoptotic bodies, DNA fragmentation, cell cycle arrest, as well as phosphatidylserine externalization, all of which are typical characteristics of apoptotic programmed cell death. Brucine-induced HepG2 cell apoptosis was caspase dependent, with caspase-3 activated by caspase-9. Brucine also caused the proteolytic processing of caspase-9. In addition, brucine caused depolarization of the mitochondrial membrane of HepG2 cells, the inhibition of which by cyclosporine A completely abrogated the activation of casapses and release of cytochrome c in brucine-treated HepG2 cells. These findings suggested a pivotal role of mitochondrial membrane depolarization in HepG2 cell apoptosis elicited by brucine. Furthermore, brucine induced a rapid and sustained elevation of intracellular [Ca2+], which compromised the mitochondrial membrane potential and triggered the process of HepG2 cell apoptosis. Finally, Bcl-2 was found to predominately control the whole event of cell apoptosis induced by brucine. The elevation of [Ca2+]i caused by brucine was also suppressed by overexpression of Bcl-2 protein in HepG2 cells. From the facts given above, Ca2+ and Bcl-2 mediated mitochondrial pathway were found to be involved in brucine-induced HepG2 cell apoptosis.     

COX-2 inhibitors in cancer treatment and prevention, a recent development

Epidemiological and experimental studies have demonstrated the effect of non-steroidal anti-inflammatory drugs (NSAIDs) in the prevention of human cancers. NSAIDs block endogenous prostaglandin synthesis through inhibition of cyclooxygenase (COX) enzymatic activity. COX-2, a key isoenzyme in conversion of arachidonic acid to prostaglandins, is inducible by various agents such as growth factors and tumor promoters, and is frequently overexpressed in various tumors. The contribution of COX-2 to carcinogenesis and the malignant phenotype of tumor cells has been thought to be related to its abilities to (i) increase production of prostaglandins, (ii) convert procarcinogens to carcinogens, (iii) inhibit apoptosis, (iv) promote angiogenesis, (v) modulate inflammation and immune function, and (vi) increase tumor cell invasiveness, although some studies indicated that NSAIDs have COX-2-independent effects. A number of clinical trials using COX-2 inhibitors are in progress, and the results from these studies will increase our understanding of COX-2 inhibition in both cancer treatment and prevention. The combination of COX-2 inhibitors with radiation or other anti-cancer or cancer prevention drugs may reduce their side effects in future cancer prevention and treatment. Recent progress in the treatment and prevention of cancers of the colon, esophagus, lung, bladder, breast and prostate with NSAIDs, especially COX-2 inhibitors, is also discussed.     

Natural plant extract tubeimoside I promotes apoptosis-mediated cell death in cultured human hepatoma (HepG2) cells

Tubeimoside I (TBMS I), an extract from Chinese herbal medicine Bolbostemma paniculatum (MAXIM.) FRANQUET (Cucurbitaceae) has been shown as a potent anti-tumor agent for a variety of human cancers, but yet to be evaluated for hepatoma that is highly prevalent in Eastern Asian countries including China. Here, we examined in vitro the cytotoxic effects of TBMS I on human hepatoma (HepG2) and normal liver (L-02) cell lines. We also investigated TBMS I-induced molecular events related to apoptosis in HepG2 cells. The results show that TBMS I inhibited the proliferation of both HepG2 and L-02 cells in a dose- and time-dependent manner, but HepG2 cells appeared more sensitive to the agent. When exposed to TBMS I for 24, 48 and 72 h, IC?? for HepG2 cells versus L-02 cells were 15.5 vs. 23.1, 11.7 vs. 16.2, 9.2 vs. 13.1 (μM, p<0.01), respectively. TBMS I induced cell shrinkage, nuclear condensation and fragmentation, cell cycle arrest at the G2/M phase, mitochondrial membrane disruption, release of cytochrome c from the mitochondria, activation of caspase 3 and 9, and shifting Bax/Bcl-2 ratio from being anti-apoptotic to pro-apoptotic, all indicative of initiation and progression of apoptosis involving mitochondrial dysfunction. Taken together, these results indicate for the first time that TBMS I potently inhibited growth in HepG2 cells by mediating a cascade of apoptosis signaling pathways. Considering its sensitivity of HepG2 cells, preferential distribution in the liver and natural product origin, TBMS I therefore may have a great potential as a chemotherapeutic drug candidate for hepatoma.     

Inhibition of tumor angiogenesis by non-steroidal anti-inflammatory drugs: emerging mechanisms and therapeutic perspectives.

Chronic intake of non steroidal anti-inflammatory drugs (NSAIDs) is associated with a reduced risk of developing gastrointestinal tumors, in particular colon cancer. Increasing evidence indicates that NSAID exert tumor-suppressive activity on pre-malignant lesions (polyps) in humans and on established experimental tumors in mice. Some of the tumor-suppressive effects of NSAIDs depend on the inhibition of cyclooxygenase-2 (COX-2), a key enzyme in the synthesis of prostaglandins and thromboxane, which is highly expressed in inflammation and cancer. Recent findings indicate that NSAIDs exert their anti-tumor effects by suppressing tumor angiogenesis. The availability of COX-2-specific NSAIDs opens the possibility of using this drug class as anti-angiogenic agents in combination with chemotheapy or radiotherapy for the treatment of human cancer. Here we will briefly review recent advances in the understanding of the mechanism by which NSAIDs suppress tumor angiogenesis and discuss their potential clinical application as anti-cancer agents.     

Atorvastatin induces mitochondrial dysfunction and cell apoptosis in HepG2 cells via inhibition of the Nrf2 pathway

Atorvastatin (ATO) is a 3‐hydroxy‐3‐methylglutaryl‐CoA reductase inhibitor widely used to treat hypercholesterolemia. However, clinical application is limited by potential hepatotoxicity. Nuclear factor‐erythroid 2‐related factor 2 (Nrf2) is a master regulator of cellular antioxidants, and oxidative stress is implicated in statin‐induced liver injury. This study investigated mechanisms of ATO‐induced hepatotoxicity and potential mitigation by Nrf2 signaling. ATO reduced Nrf2 and antioxidant enzyme superoxide dismutase‐2 (SOD2) expression in human hepatocarcinoma HepG2 cells. ATO also induced concentration‐dependent HepG2 cell toxicity, reactive oxygen species (ROS) accumulation, and mitochondrial dysfunction as evidenced by decreased mitochondrial membrane potential (MMP) and cellular adenosine triphosphate (ATP). Further, ATO induced mitochondria‐dependent apoptosis as indicated by increased Bax/Bcl‐2 ratio, cleaved caspase‐3, mitochondrial cytochrome c release and Annexin V‐fluorescein isothiocyanate/propidium iodide staining. Tert‐butylhydroquinone enhanced Nrf2 and SOD2 expression, and partially reversed ATO‐induced cytotoxicity, ROS accumulation, MMP reduction, ATP depletion and mitochondria‐dependent apoptosis. In conclusion, the present study demonstrates that ATO induces mitochondrial dysfunction and cell apoptosis in HepG2 cells, at least in part, via inhibition of the Nrf2 pathway. Nrf2 pathway activation is a potential prevention for ATO‐induced liver injury.     

COX-2 inhibition, apoptosis, and chemoprevention by nonsteroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) have as their common mechanism the inhibition of cyclooxygenase (COX) enzymes, of which two isoforms (COX-1 and COX-2) exist. The effect of NSAIDs on chemoprevention and tumor regression has been shown in animal models, epidemiologic studies, and in treatment of patients. The exact biochemical and cellular mechanisms underlying each of these phenomena is only partially understood. Processes that have been recently implicated as being important include the inhibition of tumor cell growth, prevention of angiogenesis, and induction of apoptosis in neoplastic cells.     

红枣多糖对人肝癌 HepG2细胞的抑制作用

目的：研究红枣多糖对体外培养肝癌细胞增殖的抑制作用并初步探究其可能的作用机理。方法采用M T T法测定红枣多糖对体外培养的人肝癌细胞HepG2增殖的抑制作用;流式细胞术检测红枣多糖对人肝癌细胞HepG2周期和凋亡的影响;Real time RT-PCR检测红枣多糖对人肝癌细胞HepG2中Bcl-2和caspase3 mRNA表达的影响。结果 MTT检测发现随着药物浓度的增高OD值呈现梯度递减,红枣多糖对 HepG2的IC50＝13 mg／mL ,最高浓度40 mg／mL下所得最大抑制率为68．79％;流式细胞仪检测细胞凋亡结果可见早期凋亡率随药物浓度的增加而变大;流式细胞周期分析结果可见G0-G1期细胞数逐渐增多,S期细胞数有下降趋势,并有剂量依赖性;Real time RT-PCR检测发现Bcl-2凋亡抑制基因mRNA表达随药物浓度增高而降低,而凋亡关键基因caspase-3 mRNA的表达随药物浓度增高而升高。结论红枣多糖对体外培养的肝癌细胞增值具有抑制作用,将肝癌细胞HepG2阻滞于G1期,并通过下调Bc 1-2而上调caspase-3 mRNA表达诱导 HepG2细胞凋亡。     

喜树碱及其衍生物对肝癌细胞HepG2增殖抑制与凋亡的研究

目的探讨喜树碱(CPT)及其衍生物10-羟基喜树碱(HCPT)、7-乙基喜树碱(SN22)、7-乙基-10-羟基喜树碱(SN38)在体外对肝癌细胞Hep G2增殖抑制与凋亡的影响。方法取对数期生长的HepG2细胞,分为对照组以及实验组,将4种药物配成浓度梯度0.01、0.1、1、10、100μmol/L的药物溶液。将不同浓度的药物溶液作用于肝癌细胞48 h,MTT法测定Hep G2细胞的增殖情况,Anexin V-PI染色,流式细胞仪检测细胞凋亡情况。结果 MTT法显示,4种药物对肝癌细胞Hep G2的增殖具有抑制作用,在一定范围内随着药物浓度的增加,对Hep G2细胞增殖的抑制作用逐渐增强,呈量效依赖关系,其中7-乙基-10-羟基喜树碱抑制效果最好,10-羟基喜树碱、7-乙基喜树碱次之,喜树碱抑制效果最差。不同浓度的喜树碱及衍生物处理肝癌细胞HepG2,与对照组比较差异有统计学意义,随着药物浓度的变化,细胞凋亡也呈现梯度变化,结构修饰后的SN38比SN22、HCPT及CPT作用更强。结论喜树碱及衍生物对肝癌细胞HepG2有抑制作用,并且能够诱导细胞凋亡。     

Anti-proliferative activity of fenretinide in human hepatoma cells in vitro and in vivo

N-(4-hydroxyphenyl)-retinamide (fenretinide) is a synthetic derivative of all-trans-retinoic acid and induces apoptosis in several cancer cell lines. We determined the anti-cancer activity of fenretinide using human hepatoma cell lines, Bel-7402, HepG2 and Smmc-7721. An in-vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that fenretinide exhibited growth inhibition in these cell lines, with IC50 values ranging from 13.1 to 15.5 micromol/l. In Bel-7402 cells, apoptosis with 15 micromol/l fenretinide for 0 and 48 h was 3 and 48%, respectively. In-vivo studies using the Bel-7402 xenografted athymic mouse model showed tumor inhibition rates ranging from 37.2 to 57.2%, with fenretinide administration once per 3 days at the rate of 25-100 mg/kg. Western blot analysis further showed down-regulation of procaspase-3, X-linked inhibitor of apoptosis protein and poly(ADP-ribose) polymerase cleavage in Bel-7402 cells treated with 15 mumol/l fenretinide for 48 h. Overexpression of p53 was observed in a time-dependent manner, along with a decrease in the Bcl-2/Bax ratio. Depolarized mitochondrial membranes were found in fenretinide-induced apoptotic cells, in a time-dependent manner. We conclude that fenretinide effectively inhibits the proliferation of Bel-7402, both in vitro and in vivo. Both procaspase-3 and p53-mediated apoptotic pathways are involved in its potent anti-cancer activity.     

A COX-2 inhibitor nimesulide analog selectively induces apoptosis in Her2 overexpressing breast cancer cells via cytochrome c dependent mechanisms

Epidemiological and animal model studies have suggested that non-steroidal anti-inflammatory drugs (NSAIDs) can act as chemopreventive agents. The cyclooxygenase-2 (COX-2) inhibitor nimesulide shows anti-cancer effect in different type of cancers. In the current study, five breast carcinoma cell lines were used to explore the anti-cancer mechanisms of a nimesulide derivative compound 76. The compound dose dependently suppressed SKBR-3, BT474 and MDA-MB-453 breast cancer cell proliferation with IC₅₀ of 0.9 μM, 2.2 μM and 4.0 μM, respectively. However, it needs much higher concentrations to inhibit MCF-7 and MDA-MB-231 breast cancer cell growth with IC₅₀ at 22.1 μM and 19.6 μM, respectively. Further investigation reveals that compound 76 induced apoptosis in SKBR-3 and BT474 cells. Since these cells are Her2 overexpressing cells, the Her2 intracellular signaling pathways were examined after the treatment. There was no significant changing of kinase activity. However, the cytochrome c release assay indicated that the apoptosis induced by the compound was mediated by the mitochondria. These results suggest that compound 76 selectively induce apoptosis in Her2 overexpressing breast cancer cells through the mitochondria, and could be used as a lead to design more potent derivatives.     

Ultrasonication processed <Emphasis Type="Italic">Panax ginseng berry</Emphasis> extract induces apoptosis through an intrinsic apoptosis pathway in HepG2 cells

Ginseng’s major active components, ginsenosides, have been known to show anti-cancer, neuroprotective, and anti-inflammatory activities. Ultrasonication processed Panax ginseng berry extract (UGB) contains various ginsenosides. The components are different from Panax ginseng berry extract (GBE). This study was aimed to investigate the cytotoxic mechanism of UGB in HepG2 cells, human hepatocellular carcinoma cell line. HepG2 cells were treated with UGB (0, 10, 20 μg/ml). Cell growth and cellular apoptosis were evaluated by MTT assay and Annexin V/Pi staining, respectively. Intracellular Reactive oxygen species (ROS) levels were also determined by 2′, 7′-dichlorofluorescin diacetate (DCFDA) staining. The expressions of Bax, Bcl-2 and caspase-3, the apoptotic markers, were evaluated by Western Blot. UGB dose-dependently inhibited cell growth and induced apoptotic cell death. Intracellular ROS levels were increased. UGB increased the expression of the cleaved form of caspase-3. Furthermore, UGB induced apoptosis of HepG2 cells through Bax activation and Bcl-2 inhibition. In conclusion, UGB induced apoptosis through an intrinsic pathway in HepG2 cells suggesting that UGB might play a role as a novel substance for anti-cancer effect.