bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Cotreatment of 12‐O‐tetradecanoylphorbol‐13‐acetate and H2O2 on Apoptotic Regulation via AMP‐Activated Protein Kinase–Cyclooxygenase‐2 Signals
Authors: Lee Yun‐Kyoung , Lee Mee‐Sook , Kim Young‐Min , Park Ock Jin
Published: August 2009

Colorectal cancer displays elevated cyclooxygenase‐2 (COX‐2) expression, and several studies have suggested that COX‐2 expression is associated with parameters of aggressive colon cancer. AMP‐activated protein kinase (AMPK) is a sensor of cellular energy status, and recent studies indicate that AMPK activation strongly suppresses cell proliferation in nonmalignant cells as well as in tumor cells. As a metabolic sensing signal, AMPK is involved in cancer cell apoptosis. In HT‐29 colon cancer cells, the regulation of COX‐2 expression by treating with TPA (12‐O‐tetradecanoylphorbol‐13‐acetate), low‐level H2O2, high‐level H2O2, and finally the combinations of TPA and low H2O2 or high H2O2 was investigated. We found that COX‐2 expression levels with treatment reacted as follows: with TPA alone > TPA and low H2O2 > low H2O2 > high H2O2 > TPA and high H2O2. COX‐2 regulation by these agents was accompanied by the alteration of AMPK control. The apoptotic bodies were detected as follows: high level of H2O2 > TPA > low level of H2O2. The present findings suggest that both COX‐2 stimulators (TPA and H2O2) might have differential effects on COX‐2 and AMPK regulation and further apoptotic regulation.
Anti‐inflammatory and Anticarcinogenic Effect of Genistein Alone or in Combination with Capsaicin in TPA‐Treated Rat Mammary Glands or Mammary Cancer Cell Line
Authors: Hwang Jin‐Tack , Lee Yun‐Kyoung , Shin Jang‐In , Park Ock Jin
Published: August 2009

The topical application of TPA (12‐O‐tetradecanoylphorbol‐13‐acetate) to animal skin or direct treatment of TPA to cell cultures leads to inflammatory responses by enhancing cyclooxygenase 2 (COX‐2) expression, and specific COX‐2 inhibitors counteract this kind of inflammatory response. Furthermore, suppression of these inflammatory events by dietary‐origin chemopreventive agents can provide a potential strategy to control carcinogenesis. In this in vivo study, the mammary glands of mature female rats were treated with TPA, and then the effects of genistein alone or in combination with capsaicin on suppression of inflammatory responses were examined. The combined effects of genistein and capsaicin on COX‐2, pJNK, pERK, and pp38 expressions were additive or nonadditive, depending on signals tested. In vitro MCF‐7 breast cancer cells, the apoptotic bodies as shown with Hoechst 33342 dye, exhibited a synergistic effect between genistein and capsaicin. The abilities of genistein alone or in combination with capsaicin in inhibiting breast cancer cell proliferation through the modulation of AMPK and COX‐2 were tested. AMPK activation by genistein in combination with capsaicin is critical for inhibiting COX‐2. We propose that genistein in combination with capsaicin exerts anti‐inflammatory and anticarcinogenic properties through the modulation of AMPK and COX‐2 and possibly various mitogen‐activated protein kinases synergistically or nonsynergistically.
Kidney Bean Husk Extracts Exert Antitumor Effect by Inducing Apoptosis Involving AMP‐Activated Protein Kinase Signaling Pathway
Authors: Lee Yun‐Kyoung , Hwang Jin‐Taek , Lee Mee‐Sook , Kim Young‐Min , Park Ock Jin
Published: August 2009

In this study, we investigated the molecular basis of Korean kidney bean husk extract, with emphasis on its ability to control intracellular signaling cascades of AMP‐activated protein kinase (AMPK) responsible for inducing antitumor activities in colon cancer cells. Recently, the evolutionarily conserved serine/threonine kinase, AMPK, has emerged as a possible target molecule of tumor control. We investigated the effects of Korean kidney bean husk extract on apoptosis regulation and the activation of AMPK. Korean kidney bean husk extract exhibited a series of antitumor effects such as cell death and apoptotic body appearance. These antitumor potentials were accompanied by the increase in p‐AMPK and p‐Acc as well as antitumor proteins p53 and p21. The stimulation of AMPK by this extract was blocked with the synthetic AMPK inhibitor Compound C at 10 μmol/L, and the combined treatment of Compound C and the AMPK activator AICAR (5‐aminoimiazole‐4‐carboxamide‐1‐β‐d‐ribofuranoside) showed that Compound C could inhibit the activation of AMPK at the concentration of 20 μmol/L. In conclusion, the ability of carcinogenesis control by Korean kidney bean husk extract with high potency suggests its value as an antitumor agent in colon cancer therapy.
Green Tea Catechin Controls Apoptosis in Colon Cancer Cells by Attenuation of H2O2‐Stimulated COX‐2 Expression via the AMPK Signaling Pathway at Low‐Dose H2O2
Authors: Park In‐Ja , Lee Yun‐Kyoung , Hwang Jin‐Taek , Kwon Dae‐Young , Ha Joohun , Park Ock Jin
Published: August 2009

This study investigated the apoptotic regulation by green tea catechin epigallcatechin‐3‐gallate (EGCG) on colon cancer cells in the presence of low‐dose H2O2 known to exert the activation of signal pathways leading to cell proliferation. In the presence of low‐dose H2O2, EGCG induced apoptosis and abolished the cell‐proliferative effect exhibited by low‐dose H2O2. This reduction of growth was accompanied by an activation of AMP‐activated kinase (AMPK), a decrease in cyclooxygenase‐2 (COX‐2) expression and prostaglandin E2 (PGE2) levels, and the induction of apoptotic markers such as p53 and poly(ADP‐ribose) polymerase (PARP) cleavage. The low‐dose H2O2 stimulated COX‐2 expression, and treating cells with synthetic AMPK activator AICAR (5‐aminoimiazole‐4‐carboxamide‐1‐β‐d‐ribofuranoside) resulted in greater suppression of COX‐2 expression and PGE2. By treating cells with high concentrations of the reactive oxygen species (ROS) scavenger NAC (N‐acetyl‐1‐cysteine), the apoptotic effect of EGCG was abolished and led to suppression of AMPK and COX‐2, indicating that the liberation of excessive ROS might be the upstream signal of the AMPK–COX‐2 signaling pathway even in the presence of low‐dose H2O2.
Regulatory Effect of the AMPK–COX‐2 Signaling Pathway in Curcumin‐Induced Apoptosis in HT‐29 Colon Cancer Cells
Authors: Lee Yun‐Kyoung , Park Song Yi , Kim Young‐Min , Park Ock Jin
Published: August 2009

AMP‐activated protein kinase (AMPK), a highly conserved protein in eukaryotes, functions as a major metabolic switch to maintain energy homeostasis. It also intrinsically regulates the mammalian cell cycle. Moreover, the AMPK cascade has emerged as an important pathway implicated in cancer control. In this study we investigated the effects of curcumin on apoptosis and the regulatory effect of the AMPK–cyclooxygenase‐2 (COX‐2) pathway in curcumin‐induced apoptosis. Curcumin has shown promise as a chemopreventive agent because of its in vivo regression of various animal‐model colon cancers. This study focused on exploiting curcumin to apply antitumorigenic effects through modulation of the AMPK–COX‐2 cascade. Curcumin exhibited a potent apoptotic effect on HT‐29 colon cancer cells at concentrations of 50 μmol/L and above. These apoptotic effects were correlated with the decrease in pAkt and COX‐2, as well as the increase in p‐AMPK. Cell cycle analysis showed that curcumin induced G1‐phase arrest. Further study with AMPK synthetic inhibitor Compound C has shown that increased concentrations of Compound C would abolish AMPK expression, accompanied by a marked increase in COX‐2 as well as pAkt expression in curcumin‐treated HT‐29 cells. By inhibiting AMPK with Compound C, we found that curcumin‐treated colon cancer cells were no longer undergoing apoptosis; rather, they were proliferative. These results indicate that AMPK is crucial in apoptosis induced by curcumin and further that the pAkt–AMPK–COX‐2 cascade or AMPK–pAkt–COX‐2 pathway is important in cell proliferation and apoptosis in colon cancer cells.
Is Olomoucine, a Weak CDK2 Inhibitor, Able to Induce Apoptosis in Cancer Cells?
Authors: Wandl Stefanie , Węsierska‐Gądek Józefa
Published: August 2009

Olomoucine (OLO), a substituted purine analogue, is a much weaker inhibitor of cyclin‐dependent kinases than other closely related ATP derivatives. It has been recently reported that OLO did not affect the viability of normal human MRC‐5 fibroblasts, but it inhibited the proliferation of human HL‐60 leukemia cells. Therefore, it was interesting to explore the antiproliferative effect of OLO and to characterize its action on distinct human cancer cells differing in the functional status of the cell cycle. Human HeLa cervical carcinoma and HL‐60 leukemia cells were continuously exposed to increasing concentrations of OLO for 24 h and 48 h or alternatively, cells after treatment for 24 h were postincubated in a drug‐free medium. Surprisingly, OLO more strongly affected the proliferation of HL‐60 cells than that of HeLa cells. Flow cytometric analyses revealed that OLO at higher doses increases the frequency of a hypoploid HL‐60 cell population representing cells undergoing apoptosis. These results substantiated the data of the determination of the number of viable cells. Moreover, OLO at higher doses modulates the cell cycle progression of tested cancer cells. Detailed analyses of the DNA concentration in single cells revealed that OLO‐mediated reduction of the number of G1‐phase cells was accompanied by an increase of the frequency of G2‐phase cells. The kinetics of these changes differed between both tested cancer cell lines, suggesting that some cancer cells exhibit increased susceptibility to OLO action. It remains to clarify whether the strong proapoptotic effect of OLO observed in HL‐60 cells depends on their differentiation status.
Leukocyte Elastase Inhibitor
Authors: Leprêtre Chloé , Sidoli Giuseppina , Scovassi A. Ivana , Torriglia Alicia
Published: August 2009

Poly(ADP‐ribose) polymerase‐1 (PARP‐1) uses NAD+ as a substrate to form ADP‐ribose. During apoptosis, caspases cleave PARP‐1 to avoid excessive NAD consumption. Because PARP‐1 is a key regulator of the activity of DNases involved in caspase‐dependent apoptosis, its cleavage is required to promote DNA degradation. To explore the situation in caspase‐independent cell death, we investigated the effect of PARP‐1 on the acid endonuclease leukocyte elastase inhibitor (LEI)–derived DNase II (L‐DNase II). We found for the first time an association between PARP‐1 and LEI/L‐DNase II. Unexpectedly, we observed that LEI influenced the automodification of PARP‐1.
Role of Pancreatitis‐Associated Protein 1 on Oxidative Stress–Induced Cell Death of Pancreatic Acinar Cells
Authors: Lim Joo Weon , Song Ji Yeon , Seo Jeong Yeon , Kim Hyeyoung , Kim Kyung Hwan
Published: August 2009

Previously we showed that oxidative stress induces apoptosis of pancreatic acinar cells with nuclear loss of DNA repair proteins. Oxidative stress has an important role in the pathogenesis of pancreatitis. Pancreatitis‐associated protein 1 (PAP‐1) is a protein secreted upon induction of acute pancreatitis. In this study, we investigated the role of PAP‐1 on oxidative stress–induced cell death of pancreatic acinar AR42J cells. AR42J cells were transfected with or without full‐length sense cDNA of PAP‐1 (PAP‐1 S cDNA) or antisense cDNA of PAP‐1 (PAP‐1 AS cDNA) and received oxidative stress caused by glucose oxidase acting on β‐d‐glucose, glucose/glucose oxidase. PAP‐1 mRNA expression and cell viability were determined. As a result, oxidative stress induced PAP‐1 mRNA expression in AR42J cells in a time‐dependent manner. Cell viability decreased with the concentration of glucose oxides delivered to the cells that had received glucose. Oxidative stress–induced PAP‐1 expression was augmented in the cells transfected with PAP‐1 S cDNA compared with wild‐type cells or cells transfected with control vector pcDNA. PAP‐1 induction by oxidative stress decreased in the cells transfected with PAP‐1 AS cDNA. Cell death caused by oxidative stress was inhibited in the cells transfected with PAP‐1 S cDNA, but it increased in the cells transfected with PAP‐1 AS cDNA. These results indicate that PAP‐1 may be a defensive gene for oxidative stress–induced cell death of pancreatic acinar cells.
Biological Effects of a New Vacuolar‐H,+‐ATPase Inhibitor in Colon Carcinoma Cell Lines
Authors: Supino Rosanna , Scovassi A. Ivana , Croce Anna Cleta , Bo Laura Dal , Favini Enrica , Corbelli Alessandro , Farina Carlo , Misiano Paola , Zunino Franco
Published: August 2009

Vacuolar‐H+‐ATPase plays a critical role in the cellular balance of protons, thus regulating intracellular pH and contributing to apoptosis resistance, drug resistance, and invasive and metastatic behavior of cells. NiK‐12192, a vacuolar‐H+‐ATPase inhibitor, caused a reduction in the volume and/or acidity of lysosomes, a polarization of αvβ5 integrin distribution, and a number of floating live cells, whereas signs of apoptosis appeared only after 72 h of treatment. In conclusion, NiK‐12192, by affecting vacuolar‐ H+‐ATPase activity (and intracellular pH), causes a modification of structures crucial for cell adhesion and induces cell death, likely by a modality involving an anoikis‐mediated apoptosis.
15‐Deoxy‐Δ,12,14‐prostaglandin J2 Suppresses Nuclear Factor‐κB‐Mediated Apoptosis of Helicobacter pylori‐Infected Gastric Epithelial Cells
Authors: Cha Boram , Kim Kyung Hwan , Kim Hyeyoung
Published: August 2009

Helicobacter pylori deregulates the genes that control homeostasis between apoptosis and cell proliferation of gastric epithelial cells. Nuclear factor‐κB (NF‐κB) has an important role in H. pylori‐induced apoptosis in gastric epithelial cells. The peroxisome proliferator‐activated receptor‐γ ligand 15‐deoxy‐Δ12,14‐prostaglandin J2 (15d‐PGJ2) regulates growth and the signaling cascade in H. pylori‐infected gastric epithelial cells. In the present study, we determined whether 15d‐PGJ2 inhibits apoptosis by regulating apoptotic gene expression and NF‐κB activation in gastric epithelial cells infected with CagA+, VacA+H. pylori in a Korean isolate (HP99). 15d‐PGJ2 was found to inhibit H. pylori‐induced DNA fragmentation and cell death. 15d‐PGJ2 induced downregulation of proapoptotic Bax and upregulation of antiapoptotic Bcl‐2 as well as suppression of NF‐κB activation caused by H. pylori in gastric epithelial cells. The results suggest that 15d‐PGJ2 inhibits apoptotic cell death by inhibiting NF‐κB activation and apoptotic gene expression in gastric epithelial cells.
Changes of Mitochondria and Relocation of the Apoptosis‐Inducing Factor during Apoptosis
Authors: Scovassi A. Ivana , Soldani Cristiana , Veneroni Paola , Bottone Maria Grazia , Pellicciari Carlo
Published: August 2009

During apoptosis, apoptosis‐inducing factor (AIF) is released from the mitochondrial intermembrane space to the cytosol and to the nucleus. We analyzed AIF in HeLa cells driven to apoptosis by either etoposide or actinomycin D, and we observed changes in the structure and function of mitochondria as well as the translocation of cytochrome c and AIF from mitochondria to the nucleus in early apoptosis. In cells with fragmented chromatin (i.e., in late apoptosis), the immunolabeling for AIF appeared to be distinct from chromatin, being mainly confined to mitochondria.
Mechanism of α‐Lipoic Acid‐Induced Apoptosis of Lung Cancer Cells
Authors: Choi Sang Yong , Yu Ji Hoon , Kim Hyeyoung
Published: August 2009

α‐Lipoic acid (LA) shows a protective effect on oxidative stress‐induced apoptosis while it induces apoptosis in various cancer cells. Intracellular Ca2+ plays a central role in triggering apoptotic pathways. In the present study, we aim to investigate whether LA induces apoptosis in lung cancer cells and whether Ca2+ is involved in LA‐induced apoptosis. We found that LA decreased cell viability and increased DNA fragmentation of the cells. LA activated the caspase‐independent pathway, determined by upregulation of poly(ADP‐ribose) polymerase (PARP) and increased the nuclear level of apoptosis‐inducing factor and caspase‐dependent apoptotic pathway, determined by increased levels of cytochrome c and PARP‐1 cleavage product. LA‐induced apoptotic alterations were inhibited in the cells treated with Ca2+ chelator BAPTA‐AM. In conclusion, LA induces apoptosis through caspase‐independent and caspase‐dependent pathways, which is mediated by intracellular Ca2+.
Phosphono Analogues of 2‐Oxoglutarate Protect Cerebellar Granule Neurons upon Glutamate Excitotoxicity
Authors: Bunik Victoria I. , Kabysheva Maria S. , Klimuk Eugeny I. , Storozhevykh Tatiana P. , Pinelis Vsevolod G.
Published: August 2009

Glutamate excitotoxicity is an important contributor to neuronal loss. Glutamate‐induced Ca2+ deregulation and accompanying mitochondrial depolarization are closely associated with the onset of apoptotic and necrotic neuronal death. We investigated the role in these phenomena of 2‐oxoglutarate dehydrogenase (OGDH), the enzyme participating in mitochondrial degradation of glutamate. To achieve this goal, we used specific effectors of cellular OGDH, succinyl phosphonate and its phosphonoethyl ether. Preincubation of cerebellar granule neurons with these phosphono analogues of 2‐oxoglutarate was shown to protect the cells from glutamate‐induced Ca2+ deregulation and irreversible mitochondrial depolarization, followed simultaneously by fluorescence of fura‐2FF and rhodamine 123, respectively. The protection was characterized by delay in onset and decreased propagation of Ca2+ deregulation and by reversibility of the associated mitochondrial depolarization. Compared to its phosphonoethyl ether, succinyl phosphonate exhibited both higher affinity to OGDH in vitro and better protection from Ca2+ deregulation in situ, supporting the assumption that neuroprotection by phosphonates involves their interaction with cellular OGDH. Preincubation of cerebellar granule neurons with succinyl phosphonate decreased neuronal death after excitotoxic action of glutamate. Thus, specific inhibitors of OGDH alleviate glutamate‐induced calcium deregulation, mitochondrial depolarization, and neuronal death.
Apoptosis and Modulation of Cell Cycle Control by Bile Acids in Human Leukemia T Cells
Authors: Fimognari Carmela , Lenzi Monia , Cantelli‐Forti Giorgio , Hrelia Patrizia
Published: August 2009

Depending on the nature of chemical structures, different bile acids exhibit distinct biological effects. Their therapeutic efficacy has been widely demonstrated in various liver diseases, suggesting that they might protect hepatocytes against common mechanisms of liver damage. Although it has been shown to prevent apoptotic cell death in certain cell lines, bile acids significantly inhibited cell growth and induced apoptosis in cancer cells. To better understand the pharmacological potential of bile acids in cancer cells, we investigated and compared the effects of deoxycholic acid (DCA), ursodeoxycholic acid (UDCA), and their taurine‐derivatives [taurodeoxycholic acid (TDCA) and tauroursodeoxycholic acid (TUDCA), respectively] on the induction of apoptosis and inhibition of cell proliferation of a human T leukemia cell line (Jurkat cells). All the bile acids tested induced a delay in cell cycle progression. Moreover, DCA markedly increased the fraction of apoptotic cells. The effects of TDCA, UDCA, and TUDCA were different from those observed for DCA. Their primary effect was the induction of necrosis. These distinctive features suggest that the hydrophobic properties of DCA play a role in its cytotoxic potential and indicate that it is possible to create new drugs useful for cancer therapy from bile acid derivatives as lead compounds.
Mechanism of β‐Carotene‐Induced Apoptosis of Gastric Cancer Cells: Involvement of Ataxia‐Telangiectasia‐Mutated
Authors: Jang Sung Hee , Lim Joo Weon , Kim Hyeyoung
Published: August 2009

β‐Carotene acts as an antioxidant or a pro‐oxidant depending on the concentrations that cells are treated with. Oxidative DNA damage is related to apoptosis of various cells. Ataxia‐telangiectasia‐mutated (ATM), a sensor for DNA‐damaging agents, activates a variety of effectors in multiple signaling pathways, such as DNA repair and apoptosis. In the present study, we investigated whether a high concentration of β‐carotene induces apoptosis of gastric adenocarcinoma (AGS) cells and whether ATM is involved in β‐carotene‐induced apoptosis of AGS cells. We found that β‐carotene (100 μmol/L) induced apoptosis (determined by cell viability), DNA fragmentation, and the protein levels of p53 and Bcl‐2 in AGS cells. ATM levels in the nucleus decreased from β‐carotene in AGS cells. β‐Carotene‐induced alterations, including an increase in DNA fragmentation and p53 levels and a decrease in nuclear ATM and cellular Bcl‐2 levels, were inhibited in the cells transfected with full‐length ATM cDNA compared to wild‐type cells or the cells transfected with control vector plasmid control DNA vector (pcDNA). In conclusion, β‐carotene induces apoptosis by increasing apoptotic protein p53 and decreasing anti‐apoptotic Bcl‐2 as well as nuclear ATM in AGS cells. Nuclear loss of ATM may be the underlying mechanism of β‐carotene‐induced apoptosis of gastric cancer cells.
Protective Effect of Lycopene on Oxidative Stress‐Induced Cell Death of Pancreatic Acinar Cells
Authors: Seo Jeong Yeon , Masamune Atsushi , Shimosegawa Tooru , Kim Hyeyoung
Published: August 2009

Previously we showed that the underlying mechanism of oxidative stress‐induced apoptosis is nuclear loss of DNA repair protein Ku70 and Ku80, which are involved in the DNA repair process of double‐strand breaks. Lycopene acts as an antioxidant and a singlet oxygen quencher. In the present study, we aim to investigate whether lycopene protects oxidative stress‐induced cell death of pancreatic acinar AR42J cells by preventing the loss of Ku70 in the nucleus. The cells received oxidative stress caused by glucose oxidase acting on β‐D‐glucose (glucose/glucose oxidase) and were cultured in the absence or presence of various concentrations of lycopene. Viable cell numbers, the levels of H2O2 in the medium, level of Ku70 protein, and Ku‐DNA‐binding activity were determined. As a result, glucose/glucose oxidase induced the decrease in cell viability, increase in H2O2 production, decrease in Ku70 levels in whole‐cell extracts and nuclear extracts, and decrease in Ku‐DNA‐binding activity of AR42J cells. Lycopene inhibited glucose/glucose oxidase‐induced cell death by preventing nuclear loss of Ku70 and a decrease in Ku‐DNA‐binding activity of AR42J cells. In conclusion, lycopene may be beneficial for the treatment of oxidative stress‐induced cell death by preventing loss of DNA repair protein Ku70.
Activator Protein‐1 Mediates Docosahexaenoic Acid‐induced Apoptosis of Human Gastric Cancer Cells
Authors: Lee Sun En , Lim Joo Weon , Kim Hyeyoung
Published: August 2009

Docosahexaenoic acid (DHA) shows anti‐inflammatory and/or anticancer effects in some cells. Activator protein‐1 (AP‐1) regulates cellular proliferation and apoptosis. Although recent studies demonstrate the association between gastric cancer risk and DHA, the exact molecular mechanism has not been clarified. We investigated whether AP‐1 mediates DHA‐induced apoptosis of gastric cancer cells. We found that DHA induced cell death and DNA fragmentation in parallel with the activation of extracellular signal‐regulated kinases (ERK) and c‐Jun N‐terminal kinases (JNK) as well as AP‐1. DHA increased the protein levels of p53, cytochrome c, and Bax in gastric cancer cells. DHA‐induced DNA fragmentation and protein levels of p53, cytochrome c, and Bax were inhibited in the cells transfected with c‐jun dominant‐negative mutant (TAM67). Because JNK and ERK are upstream signaling for AP‐1 activation, we suggest that DHA‐induced activation of AP‐1 may mediate apoptosis of gastric cancer cells by inducing the expression of apoptotic genes in gastric cancer cells.
Roscovitine Differentially Affects Asynchronously Growing and Synchronized Human MCF‐7 Breast Cancer Cells
Authors: Maurer Margarita , Komina Oxana , Węsierska‐Gądek Józefa
Published: August 2009

Roscovitine (ROSC), a selective blocker of cyclin‐dependent kinases (CDKs) efficiently inhibits proliferation of exponentially growing human MCF‐7 breast cancer cells by induction of cell cycle arrest and p53‐mediated apoptosis. ROSC blocks MCF‐7 cells in G2 phase in a time‐ and concentration‐dependent manner. However, ROSC exerts a much weaker antiproliferative effect on human diploid fibroblasts. Therefore, in this study we questioned whether and to what extent the antiproliferative effect of ROSC depends on the cell cycle status of cancer cells exposed to the drug. We investigated the action of ROSC on asynchronous, exponentially growing, and on synchronized human MCF‐7 breast cancer cells. MCF‐7 cells were arrested in G1 phase after serum withdrawal and in S phase by hydroxyurea. After serum refeeding, synchronized cells started to reenter the active cell cycle after 12 h. Exposure of G1‐synchronized cells to ROSC prolonged the cell cycle arrest and was accompanied by a decrease in S‐phase cells after 24 h. A similar but weaker trend occurred after ROSC administration, to cells released from G1 arrest for 4 h. ROSC diminished the frequency of S‐phase cells. Exposure of MCF‐7 cells released from G1 arrest to ROSC for 24 h resulted in an increase of the G1‐cell population by 20%. Exposure to ROSC of MCF‐7 cells released from S‐phase block increased the ratio of S‐phase cells. These results indicate that the cell cycle status of cancer cells prior to the onset of therapy determines the outcome of treatment.
Response of Retinoic Acid‐Resistant KG1 Cells to Combination of Retinoic Acid with Diverse Histone Deacetylase Inhibitors
Authors: Savickiene Jurate , Treigyte Grazina , Magnusson Karl‐Eric , Navakauskiene Ruta
Published: August 2009

Acute promyelocytic leukemia KG1 cells with t(11;17) PLZF‐RARα respond poorly to the differentiation inducer all‐trans retinoic acid (RA), and the reason for the RA resistance is the recruitment of histone deacetylase by PLZF‐RARα. Here, we demonstrate that histone deacetylase inhibitors (HDACIs), FK228, BML‐210, phenyl butyrate, and vitamin B3, in different combinations with RA, act as KG1 cell growth inhibitors. Partial differentiation to granulocytes was induced by 3 μmol/L RA, and its combination with HDAC inhibitors did not enhance RA‐induced but potentiated apoptosis. HDACIs induced accumulation of hyperacetylated histone H4. Chromatin immunoprecipitation analysis has revealed phenyl butyrate and its combinations with RA and vitamin B3 cause histone H4 acetylation in the p21 promoter regions corresponding to p53 and/or Sp1 sites. This was coincident with the activation of the transcription factor p53‐binding activity to the p21 promoter in electrophoretic mobility shift assay. The results indicate the possibility of using the combination of agents for therapeutic strategy in RA‐resistant acute myeloid leukemia to produce both differentiation and apoptosis.
The Apoptotic Paradox in Retinoblastoma
Authors: Sitorus Rita S. , Gumay Saukani , van der Valk Paul
Published: August 2009

The purpose of this study was to investigate the clinicopathological features and the expression of proteins involved in cell proliferation and the different pathways of apoptosis in retinoblastoma. Nineteen retinoblastoma patients were included, and mitotic index (MI) and apoptotic index (AI) were assessed. The expression of MIB‐1, p53, caspase‐3, Bcl‐2, and Fas protein was assessed by immunohistochemistry. Mann–Whitney U test and Fisher's exact test were used for statistical comparison. High MI (mean 16.84, range 0–66) and high MIB‐1 expression (mean 57.89, range 0–90) were found. The MI was significantly related to MIB‐1 expression (P= 0.01). The tumors showed a high apoptotic index (mean 40.26, range 1–110), and the AI was associated with the mitotic index (P= 0.02). The caspase‐3 expression was positively related to the AI (P= 0.03), although a small number of tumors with no significant or very low caspase‐3 staining showed a high number of apoptotic cells, suggestive of a caspase‐3‐independent apoptosis pathway. Bcl‐2 expression was not significantly related to AI (P= 0.07). No striking relationship was found in expression patterns of p53, Bcl‐2, caspase‐3, and Fas. In conclusion, we found that (1) cell proliferation and apoptosis are linked in retinoblastoma; (2) activation of effector caspase‐3 induces apoptosis in retinoblastoma, but Bcl‐2 overexpression does not prevent apoptosis in many tumors; (3) there is a p53‐independent pathway in approximately one‐quarter of cases; (4) the findings suggesting a caspase‐3‐independent pathway might lead to apoptosis in retinoblastoma; and, finally, we found no consistent pattern of expression of apoptotic and antiapoptotic molecules, suggesting that in retinoblastoma there is no preference for any single pathway of apoptosis. Confirmation of the results in a large set of tumors would be useful.
Protective Effects of Red Wine Flavonols on 4‐Hydroxynonenal‐Induced Apoptosis in PC12 Cells
Authors: Jang Young Jin , Kang Nam Joo , Lee Ki Won , Lee Hyong Joo
Published: August 2009

There is accumulating evidence that a moderate consumption of red wine has health benefits, such as the inhibition of neurodegenerative diseases. Although this is generally attributed to resveratrol, the protective mechanisms and the active substance(s) remain unclear. We examined whether and how red wine extract (RWE) and red wine flavonols quercetin and myricetin inhibited 4‐hydroxynonenal (HNE)‐induced apoptosis of rat pheochromocytoma PC12 cells. RWE attenuated HNE‐induced PC12 cell death in a dose‐dependent manner. HNE induced cleavage of poly(ADP‐ribose) polymerase, which is involved in DNA repair in the nucleus, and this was inhibited by RWE treatment. Treatment with RWE also inhibited HNE‐induced nuclear condensation in PC12 cells. Data of 2′,7′‐dichlorofluorescin diacetate showed that RWE protected against apoptosis of PC12 cells by attenuating intracellular reactive oxygen species. The cytoprotective effects on HNE‐induced cell death were stronger for quercetin and myricetin than for resveratrol. HNE‐induced nuclear condensation was attenuated by quercetin and myricetin. These results suggest that the neuroprotective potential of red wine is attributable to flavonols rather than to resveratrol.
Lactococcus lactis ssp. lactis Inhibits the Proliferation of SNU‐1 Human Stomach Cancer Cells through Induction of G0/G1 Cell Cycle Arrest and Apoptosis via p53 and p21 Expression
Authors: Kim Seo Young , Kim Jong‐Eun , Lee Ki Won , Lee Hyong Joo
Published: August 2009

We investigated the antiproliferative effects of the cytoplasmic fraction of Lactococcus lactis ssp. lactis (L.lac CF) on the SNU‐1 human stomach cancer cell line. The proliferation of SNU‐1 cells was inhibited by treatment with L.lac CF in a time‐ and dose‐dependent manner. L.lac CF caused G0/G1 cell cycle arrest, which was associated with an increase in p53 and p21 expression, the reduction of cyclin D1 expression, and retinoblastoma protein phosphorylation. L.lac CF induced apoptosis in SNU‐1 cells, as demonstrated by increased nucleus condensation and a sub‐G1 peak. Caspase‐3 activation, the induction of p53, and the downregulation of Bcl‐2 were also observed in L.lac CF‐treated cells. Thus, the inhibitory effect of L.lac CF on SNU‐1 cell growth is mainly attributable to the induction of G0/G1 cell cycle arrest and apoptosis.
Inhibition of P‐Glycoprotein by Wogonin Is Involved with the Potentiation of Etoposide‐Induced Apoptosis in Cancer Cells
Authors: Lee Eibai , Enomoto Riyo , Koshiba Chika , Hirano Hiroyuki
Published: August 2009

Etoposide induces apoptotic cell death in normal and cancer cells. This apoptosis plays a role not only in anticancer effects but also in adverse reactions, such as myelosuppression. Because we had previously found that wogonin, a flavone found in a plant, suppresses thymocyte apoptosis induced by etoposide, we examined the effect of this flavone in cancer cells. Wogonin significantly potentiated etoposide‐induced apoptosis in HL‐60 cells. This flavone impaired the function of P‐glycoprotein and then increased cellular content of etoposide in the cells. Thus, this flavone is likely to act as an inhibitor of P‐glycoprotein and potentiate the apoptotic action of etoposide. On the other hand, wogonin inhibited etoposide‐induced apoptosis in thymocytes, one of the normal cells. The potentiation by wogonin is likely to be a specific action for cancer cells but not normal cells. Therefore, this flavone may be used to reduce the excretion of the anticancer agents via P‐glycoprotein and increase the pharmacological action of it in cancer cells. These results suggest that wogonin may play a role in overcoming multidrug resistance.
Subapoptogenic Oxidative Stress Strongly Increases the Activity of the Glycolytic Key Enzyme Glyceraldehyde 3‐Phosphate Dehydrogenase
Authors: Cerella Claudia , D’Alessio Maria , Cristofanon Silvia , De Nicola Milena , Radogna Flavia , Dicato Mario , Diederich Marc , Ghibelli Lina
Published: August 2009

We have previously shown that oxidative stress induced by an apoptogenic dose of H2O2 leads to a temporary block of glycolytic flux via inactivation of the glycolytic key enzyme glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) in U937 cells. This corresponds to the activation of a cell defense pathway that is triggered to repair stress‐induced damage and to rescue cells from death. Here, we show that subapoptogenic doses of H2O2 affect GAPDH activity in an opposite way, leading to strong hyperactivation. This phenomenon is related to milder oxidative stress because induction of a moderate oxidative stress with an alternative approach (i.e., by decreasing glutathione content in the cells with buthionine sulphoximine) gives similar results. U937 cells hyperactivate GAPDH with the same timing observed for GAPDH alterations from apoptogenic doses of H2O2. Additionally, the prevention of the glycolytic flux sensitizes stressed cells to apoptosis. This suggests that GAPDH hyperactivity might also be an active cell response to stress, thus depicting multiple roles for glycolytic flux in different prosurvival pathways where activation depends on the strength of the oxidative stress.
Cyclooxygenase‐2 Expression in Cervical Intraepithelial Neoplasia
Authors: Kim Kidong , Jeon Yong‐Tark , Park In‐Ae , Kim Jae Weon , Park Noh‐Hyun , Kang Soon‐Beom , Lee Hyo‐Pyo , Song Yong‐Sang
Published: August 2009

To evaluate the role of cyclooxygenase (COX)‐2 during cervical carcinogenesis, we investigated COX‐2 expression in the dysplastic epithelium and stromal cells of cervical intraepithelial neoplasia (CIN). Immunohistochemical analysis with COX‐2 antibody was performed on 148 paraffin‐embedded tissue specimens of patients who were diagnosed as CIN in our institute. COX‐2 expression was evaluated separately in the dysplastic epithelium and stromal cells of CIN. The relationships between COX‐2 expression and clinicopathologic variables were examined. For the dysplastic epithelium, COX‐2 expression was negative in 137 (92.6%) and positive in 11 (7.4%) specimens. For the stromal cells, COX‐2 expression was negative in all specimens. The COX‐2 expression in dysplastic epithelium was higher in older (P= 0.038) or postmenopausal (P= 0.025) women. In conclusion, COX‐2 expression was observed only in the dysplastic epithelium but not in the stromal cells of CIN. The COX‐2 expression in dysplastic epithelium was associated with age and menopausal status.
Is There a Role for Nuclear Factor κB in Tumor Necrosis Factor‐Related Apoptosis‐Inducing Ligand Resistance?
Authors: Plantivaux Amandine , Szegezdi Eva , Samali Afshin , Egan Laurence
Published: August 2009

One strategy for cancer management consists of promoting selective apoptosis of cancer cells. Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL), a proapoptotic cytokine, is a promising anticancer agent because of its ability to selectively induce apoptosis in established tumor cell lines but not in nontransformed cells. However, many tumors have developed mechanisms of resistance against killing by TRAIL. Whether or not the transcription factor nuclear factor (κB) is involved in TRAIL resistance is uncertain, and this short review aims to summarize currently available data on this question.
Piceatannol Attenuates 4‐Hydroxynonenal‐Induced Apoptosis of PC12 Cells by Blocking Activation of c‐Jun N‐Terminal Kinase
Authors: Jang Young Jin , Kim Jong‐Eun , Kang Nam Joo , Lee Ki Won , Lee Hyong Joo
Published: August 2009

Alzheimer's disease (AD) is an age‐related neurodegenerative disorder in which apoptosis plays a potentially important role. 4‐Hydroxynonenal (HNE) is a major lipid peroxidation product produced by oxidative stress, and its level is elevated in the AD brain. In the present study, piceatannol (but not resveratrol) at the concentration of 20 μmol/L inhibited HNE‐induced PC12 cell death. Treatment with HNE induced nuclear condensation in PC12 cells, and this was attenuated by piceatannol treatment. HNE induced poly(ADP‐ribose) polymerase cleavage and decreased Bcl‐2 expression, with both of these effects being attenuated by piceatannol. Piceatannol also inhibited the phosphorylation of c‐Jun N‐terminal kinase, which is a key regulator of HNE‐induced PC12 cell death. These results indicate that piceatannol has therapeutic potential in the prevention of AD.
Gallic Acid Induces Neuronal Cell Death through Activation of c‐Jun N‐Terminal Kinase and Downregulation of Bcl‐2
Authors: Kang Min Kyung , Kang Nam Joo , Jang Young Jin , Lee Ki Won , Lee Hyong Joo
Published: August 2009

Oxidative stress induced by reactive oxygen species (ROS) is strongly associated with the pathogenesis of various neurodegenerative disorders, including Alzheimer's disease. We investigated the possible combined effects of gallic acid and resveratrol, which are major antioxidants present in fruit, including grapes, on PC12 rat pheochromocytoma (PC12) cell death. Gallic acid did not protect against H2O2‐induced PC12 cell death; it reduced the viability of PC12 cells in a dose‐dependent manner. Gallic acid also induced cleavage of poly (ADP‐ribose) polymerase, which is strongly related to apoptosis in neurons. Gallic acid induced the phosphorylation of c‐Jun N‐terminal protein kinase (JNK) and the downregulation of Bcl‐2 in PC12 cells. Treatment of PC12 cells with resveratrol increased their viability in a dose‐dependent manner by blocking the activation of JNK and the downregulation of Bcl‐2. Furthermore, gallic acid led to a progressive reduction in the viability of vector‐transfected PC12 cells, which was delayed in PC12 cells that overexpressed Bcl‐2. The JNK inhibitor SP600125 protected against gallic acid‐induced PC12 cell death. Collectively, these findings suggest that the combined effects of dietary phenolic phytochemicals on oxidative neuronal cell death and antioxidants differ in ROS‐mediated neuronal cell death.
Distribution of Centromeric Proteins and PARP‐1 during Mitosis and Apoptosis
Authors: Perdoni Federica , Bottone Maria Grazia , Soldani Cristiana , Veneroni Paola , Alpini Claudia , Pellicciari Carlo , Scovassi Anna Ivana
Published: August 2009

A large complex of proteins, called CENPs, are associated with centromeric DNA. Some of them exhibit a cell cycle‐related expression (e.g., CENP‐E and ‐F) and are required for the transition from interphase to mitosis, whereas constitutive proteins (e.g., CENP‐A, ‐B, ‐C, ‐G, and ‐H) reside permanently at the centromere and are essential for the correct kinetochore assembly. Poly(ADP‐ribose) polymerase‐1 (PARP‐1), which plays an active role in many basic processes, was described as a possible regulator of CENPs. By multicolor immunofluorescence we therefore analyzed the distribution of PARP‐1 and its interaction with CENP‐B, ‐E, and ‐F during mitosis and apoptosis.
Study of the Photodynamic Effect on the A549 Cell Line by Atomic Force Microscopy and the Influence of Green Tea Extract on the Production of Reactive Oxygen Species
Authors: Tomankova Katerina , Kolarova Hana , Bajgar Robert , Jirova Dagmar , Kejlova Kristina , Mosinger Jiri
Published: August 2009

We studied the morphology of the A549 cell line (human lung carcinoma cells) before and after photodynamic therapy (PDT) by atomic force microscopy. PDT was induced by an efficient light‐emitting diode source with total light dose of 15 J cm−2 in the presence of the sensitizer zinc‐5,10,15,20‐tetrakis(4‐sulfonatophenyl)porphyrine. In the presence of molecular oxygen, light activation of the photosensitizer, which accumulates in cancer cells, leads to the local production of reactive oxygen species (ROS). This is one of several reasons leading to cell death, and in some cases we could observe signs of apoptosis. We detected the kinetics of ROS production to be dependent on the presence of green tea extract.
Effect of Curcumin on Nuclear Factor κB Signaling Pathways in Human Chronic Myelogenous K562 Leukemia Cells
Authors: Reuter Simone , Charlet Jessica , Juncker Tom , Teiten Marie‐Hélène , Dicato Mario , Diederich Marc
Published: August 2009

Curcumin, a natural product isolated from the plant Curcuma longa, has a diverse range of molecular targets that influence numerous biochemical and molecular cascades. Curcumin has been shown to inhibit nuclear factor κB (NF‐κB) activation at several steps in the NF‐κB signaling pathways and thereby controls numerous NF‐κB‐regulated genes involved in various diseases. In the present study, we investigated the effect of curcumin pretreatment on 84 tumor necrosis factor‐α (TNF‐α)‐activated genes of NF‐κB pathways in K562 cells, using a real‐time PCR array. Our results show that transcription of 29 NF‐κB‐related mRNAs was significantly downregulated (CARD4, CCL2, CD40, CSF2, F2R, ICAM1, IKBKB, IKBKE, IL1A, IL1B, IL6, IL8, IRAK2, MALT1, MAP3K1, MYD88, NFKB1, NFKB2, NFKBIA, PPM1A, RAF1, RELB, STAT1, TLR3, TNF, TNFαIP3, TNFSF10, and TICAM1), whereas 10 mRNAs were induced (AGT, CASP1, CSF3, FOS, IFNG, IL10, TICAM2, TLR2, TLR9, and TNFRSF7). Western blot analysis of CD40, NFKB1 (p50), RELB, NFKBIA (IκBα), and IL10 as well as an IL8 secretion assay confirmed our results. Taken together, we show that curcumin regulates an impressive number of NF‐κB genes within the different NF‐κB signaling pathways.
Monitoring of Long‐Term Effects of Resveratrol on Cell Cycle Progression of Human HeLa Cells after Administration of a Single Dose
Authors: Kramer Matthias P. , Węsierska‐Gądek Józefa
Published: August 2009

Expression of the human papillomavirus‐encoded oncoproteins E6 and E7 in human HeLa cervical carcinoma cells results in their escape from the proper control of the cell cycle progression. Therefore, their susceptibility to agents modulating cell cycle differs from that in cells in which the control of cell cycle regulation is intact. Recently, a number of experimental studies revealed that polyphenols, especially resveratrol, could exert a strong antiproliferative effect. Polyphenols (e.g., resveratrol or epicatechins), potent antioxidant agents, are abundant components of our diet and, therefore, may not only affect the proliferation of healthy cells in the organism but also modulate the action of distinct anticancer drugs. Indeed, it has been shown that resveratrol enhances the antimitotic effect exerted by roscovitine (ROSC), a potent cyclin‐dependent kinase inhibitor, on human MCF‐7 breast cancer cells. In the present contribution the action of resveratrol alone and in combination with ROSC on human HeLa cells was determined. Resveratrol inhibited proliferation of exponentially growing HeLa cells. Exposure of HeLa cells to 50 μmol/L resveratrol blocked cells in the S phase in a time‐dependent manner. After 12 h the population of G2/M‐phase cells completely disappeared, and during a further 12 h the frequency of S‐phase cells markedly increased and reached approximately 90%. Thus, resveratrol synchronized HeLa cells in the S phase. After removal of resveratrol, synchronized HeLa cells rapidly progressed through the cell cycle. Four hours after medium change, more than 70% of cells moved into the G2/M phase. Moreover, resveratrol combined with ROSC enhanced the antiproliferative action of resveratrol.
Phase I/IIa Study of Combination Chemotherapy with CKD‐602 and Cisplatin in Patients with Recurrent Epithelial Ovarian Cancer
Authors: Kim Hee Seung , Kang Sok‐Bom , Seo Sang‐Soo , Han Seung‐Su , Kim Jae Weon , Park Noh‐Hyun , Kang Soon‐Beom , Lee Hyo‐Pyo , Song Yong Sang
Published: August 2009

The aim of this study was to determine the maximum tolerated dose (MTD) and therapeutic efficacy of a newly developed CKD‐602 topoisomerase I inhibitor and cisplatin in patients with recurrent epithelial ovarian cancer. CKD‐602 (0.30 mg/m2 daily for 5 days) and cisplatin (60 mg/m2 on day 5) were administered to patients every 3 weeks with dose adjustment of CKD‐602 by 0.05 mg/m2 daily until the MTD was reached. Dose‐limiting toxicity was defined as grade ≥ 3 neutropenia or thrombocytopenia for more than 4 days or accompanied by fever ≥ 38.5°C, infection, hemorrhage, or transfusion; grade ≥ 3 nonhematological toxicity except for alopecia, nausea, and vomiting. We enrolled 26 patients with recurrent epithelial ovarian cancer who had measurable disease (MD) estimated by computed tomography scan (n= 12) and nonmeasurable disease (NMD) evaluated by serum CA‐125 levels (n= 14). All patients received 188 cycles of CKD‐602 and cisplatin with a median number of six cycles per patient (range, 2 to 12). MTD of CKD‐602 was 0.30 mg/m2 daily. The overall response rate was 69.2% (18/26) with 58.3% (7/12) and 78.6% (11/14) in MD and NMD, respectively. Among the responsive patients, 14 were platinum sensitive (14/18, 77.7%) and four were platinum resistant (4/8, 50.0%). The most common toxicity was grade ≥ 3 neutropenia developing in 17 patients (65.4%) and 72 cycles (38.3%). Grade 3 nausea and anorexia were the most common gastrointestinal toxicities, developing in 15 cycles (8.0%) of four patients (15.4%) and 10 cycles (5.3%) of five patients (19.3%), respectively. The median disease‐free interval was 6 months (range 0–26 months). CKD‐602 at a concentration of 0.3 mg/m2 daily for 5 days and cisplatin at 60 mg/m2 on day 5 every 3 weeks showed high efficacy, with acceptable toxicity, against platinum‐sensitive/resistant recurrent epithelial ovarian cancer.
Neuronal Apoptosis in Alzheimer's Disease
Authors: Bertoni‐Freddari Carlo , Fattoretti Patrizia , Casoli Tiziana , Di Stefano Giuseppina , Balietti Marta , Giorgetti Belinda , Perretta Gemma
Published: August 2009

To assess the role of the mitochondrial metabolic competence (MMC) in the development of age‐related changes, we measured the levels of immunohistochemically stained (IH) mitochondrial‐ and nuclear‐encoded subunits of cytochrome oxidase (COX II and COX IV, respectively) and compared these data with mRNA in situ hybridization (ISH) of the same subunits and with cytochemically evidenced COX activity in the temporal (TC) and frontal (FC) cortex of adult and late‐adult monkeys. Quantitative cytochemistry of COX activity was performed by calculating the ratio (R) of the area of the cytochemical precipitate to the area of the respective organelle. Although ISH studies showed reduced gene expression of both subunits in FC of late‐adult monkeys, no significant age‐related difference was found either in TC or FC when considering the IH data. R was significantly increased in FC of late‐adult animals, and a quartile distribution of the mitochondrial area showed that R is higher in the FC of older animals independent of the organelle size. The assessment of COX genetic and phenotypic parameters reliably reports on MMC because this enzyme is the terminal complex of the electron transport chain. Taken together, the present IH, ISH, and R findings suggest that, with advancing age, compensating mechanisms are activated to preserve the mitochondrial functional metabolic capacities. Although significant mitochondrial defects are currently reported to occur in Alzheimer's disease pathogenesis, our data document that MMC is actively involved in the physiological rearrangement of the age‐related neuronal network and may provide substantial metabolic support for the energy demand of neuronal apoptosis.