Cell cycle and apoptosis

Trans-platinum(II) complexes with cyclohexylamine as expectator ligand induce necrosis in tumour cells by inhibiting DNA synthesis and RNA transcription

BACKGROUND

Enhanced removal of cisplatin-DNA adducts has been reported as one of main causes of cell resistance to cisplatin. This particular resistance mechanism may be circumvented by platinum complexes that bind differently to DNA. One line of work is focussed on trans platinum complexes, some of which exhibit antitumour activity similar to or even higher than that of their cis counterparts.

METHODS

We synthesised new trans platinum complexes, trans-[PtCl2(cyclohexylamine)(dimethylamine)] and trans-[PtCl2(OH)2(cyclohexylamine)(dimethylamine)], previously evaluated as cytotoxic agents towards different cancer and normal cell lines. These trans platinum compounds were highly effective against a panel of tumoral cell lines either sensitive to or with acquired resistance to cisplatin.

RESULTS

In the present work we examined the mechanisms induced by these compounds to cause tumour cells toxicity. We have found that these compounds induced a complete blockade at the S phase of the cell cycle inhibiting total mRNA transcription and precluding p53 activation.

CONCLUSION

In contrast to other DNA-damaging agents, these compounds do not induce senescence-associated permanent arrest. Furthermore, only a small percentage of these cells enter into apoptosis, with most of the population dying by a necrosis-like mechanism.

Growth inhibition and induction of G1 phase cell cycle arrest in human lung cancer cells by a phenylbutenoid dimer isolated from Zingiber cassumunar

In our previous study, a novel phenylbutenoid dimer (+/-)-trans-3-(3,4-dimethoxyphenyl)-4-[(E)-3,4-dimethoxystyryl]cyclohex-1-ene (PSC), isolated from Zingiber cassumunar ROXB. (Zingiberaceae), inhibited proliferation of various human cancer cells with the IC(50) values ranging 10 to 30 microM. Prompted by these anti-proliferative effects, we performed additional studies in A549 human lung cancer cells in order to investigate the mechanism of action. PSC arrested cell cycle progression at the G0/G1 phase in a concentration- and time-dependent manner. PSC dose-dependently induced cyclin-dependent kinase (CDK) inhibitor p21 expression, whereas the expression of cyclin D1, cyclin A, CDK4, CDK2, and proliferating cell nuclear antigen (PCNA) were decreased by treatment with PSC. These results suggest that one of the anti-proliferative mechanisms of PSC is to suppress cell cycle progression by increasing p21 expression and down-regulating cyclins and CDKs. This study characterizes additional biological activity of this novel phenylbutenoid dimer and expands its therapeutic potential for cancer as a chemotherapeutic agent derived from natural products.

Restoration of p53 expression in human cancer cell lines upregulates the expression of Notch1: implications for cancer cell fate determination after genotoxic stress

Following genotoxic stress, transcriptional activation of target genes by p53 tumor suppressor is critical in cell fate determination. Here we report that the restoration of p53 function in human cancer cell lines that are deficient in p53 function upregulated the expression of Notch1. Interestingly, the expression of wild-type p53 in human prostate and breast cancer cell lines correlated well with increased expression of Notch1. Furthermore, knockdown of p53 expression in cancer cells that express wild-type p53 resulted in reduced expression of Notch1. Importantly, genotoxic stress to cancer cells that resulted in activation of p53 also upregulated the expression of Notch1. Moreover, p53-mediated induction of Notch1 expression was associated with stimulation of the activity of Notch-responsive reporters. Notably, p53 differentially regulated the expression of Notch family members: expression of Notch2 and Notch4 was not induced by p53. Significantly, treatment of cells with gamma secretase inhibitor, an inhibitor of Notch signaling, increased susceptibility to apoptosis in response to genotoxic stress. Together, our observations suggest that p53-mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress.

Inhibition of CDK4 impairs proliferation of pancreatic cancer cells and sensitizes towards TRAIL-induced apoptosis via downregulation of survivin

Pancreatic ductal adenocarcinoma is one of the most common causes of cancer death in Western countries with an average survival after diagnosis of 3-6 months and a five-year survival rate under 5%. Because of the lack of effective therapies, there is the need to characterize new molecular treatment strategies. Abnormal regulation of the cell cycle is a hallmark of neoplasia. Cyclin-dependent kinase 4 (CDK4), a key regulator of G1-phase of the cell cycle, has been shown to be overexpressed in pancreatic cancer. Until now, the contribution of CDK4 to tumor maintenance of pancreatic cancer has not been investigated. In this study, we used the chemical CDK4 inhibitor 2-bromo-12,13-dihydro-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-dione, as well as RNA interference, to investigate the function of CDK4 in pancreatic cancer cells. Both approaches led to a reduction of pancreatic cancer cell proliferation due to G1-phase cell cycle arrest and Rb activation. Furthermore, we observed increased sensitivity of G1-arrested pancreatic cancer cells towards TRAIL-induced apoptosis. Sensitization towards TRAIL was due to the transcriptional downregulation of survivin. These findings show that a combined sensitizer/inducer strategy may be a potential therapeutic strategy for pancreatic ductal adenocarcinoma.

Different cell cycle modulation following treatment of human ovarian carcinoma cells with a new platinum(IV) complex vs cisplatin

Platinum (IV) derivative with adamantylamine-LA-12-represents a new generation of highly efficient anti-cancer drug derived from cisplatin and is currently in the final stage of phase I clinical trials. Understanding the specific mechanisms of its effects on cell cycle is necessary for defining the mode of action of LA-12. In this study, we characterized the ability of LA-12 to induce cell cycle perturbations in ovarian cancer cell line A2780 as compared to equitoxic cisplatin treatment. LA-12 induced a permanent accumulation of A2780 cells in S phase while cisplatin caused G2/M arrest at 24-h time point, where we also detected an increased expression of Gadd45alpha protein. Although both derivatives induced a rapid increase of p53 expression, this was not associated with a down-regulation of Mdm2 protein. Increased expression of p21(Cip1/WAF1) protein and its association with cyclins A and B1 suggested that this cyclin-dependent kinase inhibitor might contribute significantly to the observed perturbations of cell cycle. The results of this study provide insight into the mechanism of action of platinum-based derivative with adamantylamine on cell cycle in ovarian cancer cells. The differences between effects of LA-12 and cisplatin suggest that more attention should be paid to elucidation of modes of action of novel platinum(IV) complexes at cellular level.

p27kip1 overexpression promotes paclitaxel-induced apoptosis in pRb-defective SaOs-2 cells

p27kip1 is a cyclin-dependent kinase (CDK) inhibitor, which controls several cellular processes in strict collaboration with pRb. We evaluated the role of p27kip1 in paclitaxel-induced apoptosis in the pRb-defective SaOs-2 cells. Following 48 h of exposure of SaOs-2 cells to 100 nM paclitaxel, we observed an increase in p27kip1 expression caused by the decrease of the ubiquitin-proteasome activity. Such increase was not observed in SaOs-2 cells treated with the caspase inhibitors Z-VAD-FMK, suggesting that p27kip1 enhancement at 48 h is strictly related to apoptosis. Finally, we demonstrated that SaOs-2 cells transiently overexpressing the p27kip1 protein are more susceptible to paclitaxel-induced apoptosis than SaOs-2 cells transiently transfected with the empty vector. Indeed, after 48 h of paclitaxel treatment, 41.8% of SaOs-2 cells transiently transfected with a pcDNA3-p27kip1 construct were Annexin V-positive compared to 30.6% of SaOs-2 cells transfected with the empty vector (P < 0.05). In conclusion, we demonstrated that transfection of the pRb-defective SaOs-2 cells with the p27kip1 gene via plasmid increases their susceptibility to paclitaxel-induced apoptosis. The promoting effect of p27kip1 overexpression on apoptosis makes p27kip1 and proteasomal inhibitors interesting tools for therapy in patients with pRb-defective cancers.

Structure-activity relationship of new trans-platinum(II) and (IV) complexes with cyclohexylamine. Interference with cell cycle progression and induction of cell death

The new trans-Pt complexes, derived from trans-[PtCl2(amine)(dimethylamine)] and trans-[PtCl2(OH)2(amine)(dimethylamine)], were synthesized and characterized studying the structure-activity relationship and testing their antiproliferative activity. Their evaluation as cytotoxic agents towards different cancer and normal cell lines is presented. These compounds are active in a panel of tumor cell lines at low micromolar range. Compounds seems to be more active in tumoral than in normal primary human cell lines. Cytotoxic activity is closely related to the amine ligand. Cyclohexylamine ligand was the most active among the amine-ligands tested. Cytotoxic activity correlates with an increase in annexin V positive cells indicating an apoptotic effect of the compounds. Mechanistically, the antitumor activity correlates with a blockade of the cell cycle in S phase and a complete abolishment of G2/M checkpoint arrest suggesting physical interaction of compound with DNA inhibiting S phase transition.

The retinoblastoma gene is involved in multiple aspects of stem cell biology

Genetic programs controlling self-renewal and multipotentiality of stem cells have overlapping pathways with cell cycle regulation. Components of cell cycle machinery can play a key role in regulating stem cell self-renewal, proliferation, differentiation and aging. Among the negative regulators of cell cycle progression, the RB family members play a prominent role in controlling several aspects of stem cell biology. Stem cells contribute to tissue homeostasis and must have molecular mechanisms that prevent senescence and hold 'stemness'. RB can induce senescence-associated changes in gene expression and its activity is downregulated in stem cells to preserve self-renewal. Several reports evidenced that RB could play a role in lineage specification of several types of stem cells. RB has a role in myogenesis as well as in cardiogenesis. These effects are not only related to its role in suppressing E2F-responsive genes but also to its ability to modulate the activity of tissue-specific transcription factors. RB is also involved in adipogenesis through a strict control of lineage commitment and differentiation of adipocytes as well in determining the switch between brown and white adipocytes. Also, hematopoietic progenitor cells utilize the RB pathway to modulate cell commitment and differentiation. In this review, we will also discuss the role of the other two RB family members: Rb2/p130 and p107 showing that they have both specific and overlapping functions with RB gene.

Electron-transfer capacity of catechin derivatives and influence on the cell cycle and apoptosis in HT29 cells

Galloylated and nongalloylated catechin conjugates with cysteine derivatives have been synthesized and evaluated for their capacity to scavenge free radicals and to influence crucial functions (cell cycle, apoptosis) in HT29 colon carcinoma cells. We show that the nonphenolic part of the molecule modified the capacity of catechins to donate hydrogen atoms and to transfer electrons to free radicals. Nongalloylated derivatives did not significantly influence either the cell cycle or apoptosis. Among the galloylated species, 4beta-[S-(O-ethyl-cysteinyl)]epicatechin 3-O-gallate, which showed a high electron-transfer capacity (5 e- per molecule), arrested the cell cycle and induced apoptosis as expected for galloylated catechins such as tea (-)-epigallocatechin 3-O-gallate. 4beta-[S-(N-Acetyl-O-methyl-cysteinyl)]epicatechin 3-O-gallate, which showed the highest hydrogen-donating capacity (10 H per molecule) while keeping the electron-transfer capacity low (2.9 e- per molecule), did not trigger any significant apoptosis. The gallate moiety did not appear to be sufficient for the pro-apoptotic effect of the catechin derivatives in HT29 cells. Instead, a high electron-transfer capacity is more likely to be behind this effect. The use of stable radicals sensitive exclusively to electron transfer may help to design molecules with either preventive scavenging action (high hydrogen donation, low electron transfer) or therapeutic pro-apoptotic activity (high electron transfer).

Sophorolipid produced from the new yeast strain Wickerhamiella domercqiae induces apoptosis in H7402 human liver cancer cells

The effects of sophorolipid on the growth and apoptosis of H7402 human liver cancer cells were investigated. By treatment with sophorolipid, a dose- and time-dependent inhibition of cell proliferation was observed. The cells developed many features of apoptosis, including condensation of chromatin, nuclear fragmentation, and appearance of apoptotic bodies, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling positive cells were stained dark brown. Sophorolipid treatment induced apoptosis in H7402 cells by blocking cell cycle at G1 phase and partly at S phase, activating caspase-3, and increasing Ca2+ concentration in cytoplasm. These findings may suggest a potential use of sophorolipid for liver cancer treatment.

Antiproliferative properties of Padma Lax and its components ginger and elecampane

BACKGROUND

Padma Lax (PL) is a multi-component herbal laxative, derived from traditional Tibetan medicine. It has been used in the treatment of constipation dominant irritable bowel syndrome. Beyond its purgative and bowel-regulating properties we found it to exhibit antiproliferative properties.

MATERIALS AND METHODS

C6 tumor cells were incubated with either an ethanolic or aqueous extract of PL. Cell proliferation, cell cycle, percentage of apoptotic cells, caspase-3/-7 activity as well as mitochondrial membrane potential were determined.

RESULTS

Ethanolic extracts of PL inhibited cell proliferation in a dose- and time-dependent manner (half max concentration: 384.4 mug/ml after 48 h of incubation). Aqueous extracts were less effective. Ginger and elecampane were the active components of PL in respect to its antiproliferative action and were found to act synergistically. Supplementing the culture medium with polyamines could not override the cytostatic action of PL. Incubation of C6 cells with PL in the presence of catalase proved that the PL effect was specific and not due to oxidative stress. PL had no effects on the cell cycle at a low dose but arrested cells in G1 at high concentrations. Reduction of cell numbers was found to be due to apoptosis. The caspase- 3/-7 pathway was not involved in the PL-induced cell death. However, mitochondrial membrane potential was lost during the course of incubation with PL indicating a mitochondrial- but not caspase-mediated induction of apoptosis.

CONCLUSION

PL exhibits antiproliferative properties which may be beneficial to prevent constipation-related cancer. This study may also contribute to a future development of a new herbal-based antiproliferative treatment.

Petrotetrayndiol A induces cell cycle arrest and apoptosis in SK-MEL-2 human melanoma cells through cytochrome c-mediated activation of caspases

We investigated the possible mechanisms by which petrotetrayndiol A, a polyacetylene from the sponge Petrosia sp., exerts its anti-proliferative activity in cultured SK-MEL-2 human melanoma cells. Petrotetrayndiol A-treated SK-MEL-2 cells showed growth inhibition and induction of apoptosis in a dose-dependent manner as measured by MTT assay, fluorescent microscopy and flow cytometric analysis. Flow cytometric analysis revealed that petrotetrayndiol A resulted in G2/M arrest in the cell cycle progression which was associated with a marked decrease in the protein expression of cyclin B1 and its activating partner Cdc2 with concomitant inductions of p21WAF1/CIP1. The increase in apoptosis was associated with a dose-dependent up-regulation of cytosolic factor, such as Bax and release of cytochrome c, and down-regulation of Bcl-2. We also observed activation of caspase-9 and caspase-3, DNA ladder formation, proteolytic degradation of poly(ADP-ribose)-polymerase (PARP), and selective down-regulation of cIAP-1. The apoptotic manifestations, such as PARP cleavage and DNA fragmentation, were abolished in the presence of the tripeptide caspase inhibitor z-VAD-fmk and a caspase-3-specific inhibitor Ac-DEVD-cho. Our data thus demonstrate that petrotetrayndiol A-induced apoptosis and growth inhibition of SK-MEL-2 cells is dependent on caspase activation.

Anti-tumor and proapoptotic effect of novel synthetic benzophenone analogues in Ehrlich ascites tumor cells

A series of substituted benzophenone analogues, (2-aroyl-4-methylphenoxy)acetamides 4a-e, have been synthesized via three-step synthesis sequence beginning with the 2-hydroxybenzophenones 1a-e in excellent yield. 1a-e on reaction with ethyl chloroacetate afford ethyl (2-aroyl-4-methylphenoxy)acetates 2a-e which on alkaline hydrolysis afforded (2-aroyl-4-methylphenoxy)ethanoic acid 3a-e. Compounds 3a-e on condensation with p-chloroaniline furnished benzophenone analogues 4a-e. In the present report, we investigated the anti-tumor and proapoptotic effect of benzophenones in Ehrlich ascites tumor (EAT) cells. Treatment of benzophenones in vivo resulted in inhibition of proliferation of EAT cells and ascites formation. Further, we demonstrate that the induction of apoptosis in EAT cells is mediated through activation of caspase-3. These results suggest a further possible clinical application of these synthetic compounds as potent anti-tumor and proapoptotic compounds.

Adrenomedullin prevents apoptosis in prostate cancer cells

The 52-aminoacid peptide adrenomedullin (AM) is expressed in the normal and malignant prostate. We have previously shown that prostate cancer cells produce and secrete AM, which acts as an autocrine growth inhibitory factor. We have evaluated in the present study the role of AM in prostate cancer cell apoptosis, induced either by serum deprivation or treatment with the chemotherapeutic agent etoposide (which acts as an inhibitor of topoisomerase II). For this purpose we over-expressed AM in PC-3, DU 145 and LNCaP cells, which were transfected with an expression vector carrying AM. We also treated the parental cell lines with synthetic AM in normal culture conditions and in conditions of induced-apoptosis. After serum removal, AM prevented apoptosis in DU 145 and PC-3 cells, but not in LNCaP cells. When treated with etoposide, AM prevented apoptosis in PC-3 and LNCaP cells, but not in DU 145 cells. Cell cycle analysis demonstrated a significant decrease in the percentage of AM-overexpressing PC-3 cells in the subG0/G1 phase after treatment with etoposide, as compared to the percentage of mock-transfected PC-3 treated cells. Western blot showed that protein levels of phosphorylated ERK1/2 increased in parental PC-3 cells after treatment with etoposide. In PC-3 cells overexpressing AM, phosphorylated ERK1/2 basal levels were lower than basal levels of parental PC-3 cells, and treatment with etoposide did not result in such an increase. Etoposide produced a significant increase in cleaved PARP in parental PC-3 cells. However, PC-3 clones overexpressing AM that were treated with etoposide only showed a mild increase in fragmented PARP. The ratio Bcl-2/Bax was reduced in parental or mock-transfected PC-3 cells after treatment with etoposide. On the contrary, this ratio was not reduced in PC-3 clones with AM overexpression that were treated with etoposide. All these data demonstrate that AM plays a protective role against induced apoptosis in prostate cancer cells. These results may have important implications in prostate cancer resistance to chemotherapeutic agents.

Platinum(IV) complex with adamantylamine overcomes intrinsic resistance to cisplatin in ovarian cancer cells

OBJECTIVES

The resistance of tumor cells to cisplatin remains a major cause of treatment failure in cancer patients. In this study, the ability of Pt(IV) complex with adamantylamine-LA-12 and its reduced counterpart with lower oxidation state Pt(II)-LA-9 to overcome intrinsic cisplatin resistance was investigated.

METHODS

The ovarian adenocarcinoma SK-OV-3 cells were exposed to cisplatin, LA-9, or LA-12 for 72 h and the effects of drug concentrations that caused 10% or 50% inhibition of cell proliferation were determined. After 24-72 h of sustained exposure viability, apoptosis and inhibition of proliferation were analyzed. DNA synthesis and cell cycle analysis were performed simultaneously in order to determine the modulation of cell cycle after platinum complexes treatment.

RESULTS

Lung Resistance-related Protein (LRP/MVP) was detected in SK-OV-3 cells but not in the other two ovarian cancer lines with different sensitivity to cisplatin. LRP/MVP overexpression may be an important factor contributing to intrinsic cisplatin resistance. Interestingly, Pt(IV) complex-LA-12 had approximately 2.7-fold lower IC(50) concentration than LA-9 or cisplatin in SK-OV-3 cells. Moreover, LA-12 caused persistent accumulation of cells in S-phase of the cell cycle while LA-9 and cisplatin treatment-induced S-phase arrest was transient and shifted to G(2)/M-phase at later intervals. Apoptosis seemed to be not the dominant type of cell death caused by such the derivatives, but it was the most intensive after LA-12 treatment.

CONCLUSIONS

We found strong differences between effects of Pt(IV) complex-LA-12 and Pt(II) derivatives-LA-9 and cisplatin on cytokinetic parameters. Overall, LA-12 but not its reduced Pt(II) counterpart LA-9 is the compound effective in p53 null human ovarian cancer cells and it is able to overcome intrinsic cisplatin resistance in these cells.

Ircinin-1 induces cell cycle arrest and apoptosis in SK-MEL-2 human melanoma cells

We investigated the effects of ircinin-1, a lipid compound (a C25 sesterterpene tetronic acid) isolated from marine sponges (Sarcotragus sp.), on the modulation of cell cycle and induction of apoptosis in SK-MEL-2 human skin cancer cells (mutant p53). Ircinin-1 treatment on SK-MEL-2 cells resulted in a dose-dependent inhibition of cell growth and induced apoptotic cell death. Flow cytometric analysis revealed that ircinin-1 resulted in G1 arrest in cell cycle progression which was associated with a marked decrease in the protein expression of D-type cyclins and their activating partners Cdk 4 and 6 with concomitant inductions of p21WAF1/CIP1 and p27KIP1. The induction of p21WAF1/CIP1 appears to be transcriptionally upregulated and is p53-independent. In addition, ircinin-1 suppressed the phosphorylation of pRb protein and increased the co-association of pRb or proliferating cell nuclear antigen (PCNA) with p21WAF1/CIP1 in these cells. Ircinin-1 treatment also resulted in induction of apoptosis as determined by morphological changes, DNA fragmentation, alternated ratio of Bax/Bcl-2, cleavages of poly(ADP-ribose) polymerase and PLC-gamma1, and flow cytometric analysis. Ircinin-1 also induced cytochrome c release, cleavage activations of caspase-3 and -9, and upregulation of Fas and Fas-L. Even though the inhibitor of apoptosis protein (IAP) was expressed in ircinin-1-untreated or -treated SK-MEL-2 cells, only the level of cIAP-1, but not XIAP or cIAP-2, was decreased during ircinin-1-induced apoptosis at Western blot and RT-PCR studies. Taken together, these findings suggest that ircinin-1 has strong potential for development as an agent for prevention against skin cancer.

Resveratrol modulates gene expression associated with apoptosis, proliferation and cell cycle in cells with mutated human c-Ha-Ras, but does not alter c-Ha-Ras mRNA or protein expression

An accumulating body of evidence suggests that resveratrol can inhibit carcinogenesis through antiproliferative and apoptotic effects. One proposed mechanism for this is the modulation of genes, for example, Ras and p53, frequently associated with human cancer. To test the effect of resveratrol on gene expression, we used the WR-21 cell line because it contains a mutated human c-Ha-ras gene. Cells at > or =70% confluency were incubated with media alone or with increasing concentrations of trans-resveratrol (0.1-1000 microM) for 24 h. Resveratrol (30-100 microM) decreased cellular proliferation by 80% (bromodeoxyuridine incorporation) and increased apoptosis by 60% (TUNEL). Cells were then treated with media alone or with 50-microM resveratrol for 24 h. RNA was isolated for nylon-based macroarray analyses and protein for immunoblotting. Resveratrol increased (+) and decreased (-) gene expression associated with apoptosis (Birc5+, Cash+, Mcl-1+, Mdm2+, Rpa-like+), cellular proliferation (Ctsd+, Mdm2+, Egr1+, ODC+) and cell cycle (cyclin D+, cyclin g+, Gadd45a-, Mad2l-, Mdm2+). Resveratrol consistently increased by > or =6-fold Mdm2 expression and other downstream p53 effectors, but not p53 itself at 24 h. Subsequent cell cycle analysis indicated a significant accumulation of cells in G2/M, and a decrease in G1/G0 suggesting a G2/M blockade. Further RT-PCR and Western blot analyses indicated no differential changes in Ras mRNA expression or p21(ras) protein levels, respectively. These results suggest that resveratrol potently inhibits cellular proliferation, increases apoptosis, alters cell cycle dynamics and modulates associated gene expression. Furthermore, these effects appear mediated, in part, by p53 without direct modulation of mutant c-Ha-ras expression.

G1/S cell cycle arrest provides anoikis resistance through Erk-mediated Bim suppression

Proper attachment to the extracellular matrix is essential for cell survival. Detachment from the extracellular matrix results in an apoptotic process termed anoikis. Anoikis induction in MCF-10A mammary epithelial cells is due not only to loss of survival signals following integrin disengagement, but also to consequent downregulation of epidermal growth factor (EGFR) and loss of EGFR-induced survival signals. Here we demonstrate that G(1)/S arrest by overexpression of the cyclin-dependent kinase inhibitors p16(INK4a), p21(Cip1), or p27(Kip1) or by treatment with mimosine or aphidicolin confers anoikis resistance in MCF-10A cells. G(1)/S arrest-mediated anoikis resistance involves suppression of the BH3-only protein Bim. Furthermore, in G(1)/S-arrested cells, Erk phosphorylation is maintained in suspension and is necessary for Bim suppression. Following G(1)/S arrest, known proteins upstream of Erk, including Raf and Mek, are not activated. However, retained Erk activation under conditions in which Raf and Mek activation is lost is observed, suggesting that G(1)/S arrest acts at the level of Erk dephosphorylation. Thus, anoikis resistance by G(1)/S arrest is mediated by a mechanism involving Bim suppression through maintenance of Erk activation. These results provide a novel link between cell cycle arrest and survival, and this mechanism could contribute to the survival of nonreplicating, dormant tumor cells that avert apoptosis during early stages of metastasis.

TRAIL is a key target in S-phase slowing-dependent apoptosis induced by interferon-beta in cervical carcinoma cells

Interferon (IFN)-beta induces S-phase slowing and apoptosis in human papilloma virus (HPV)-positive cervical carcinoma cell line ME-180. Here, we show that apoptosis is a consequence of the S-phase lengthening imposed by IFN-beta, demonstrating the functional correlation between S-phase alteration and apoptosis induction. In ME-180 cells, where p53 function is inhibited by HPV E6 oncoprotein, IFN-beta effects on cell cycle and apoptosis occur independently of p53. The apoptosis due to IFN-beta is mediated by the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a manner dependent on the S-phase deregulation. IFN-beta appears to increase TRAIL expression both directly at the mRNA level and indirectly by augmenting surface protein levels as a consequence of the induced S-phase cell accumulation. Moreover, the alteration of the S-phase due to IFN-beta promotes TRAIL-dependent apoptosis by potentiating cell sensitivity to TRAIL, possibly through induction of a proapoptotic NF-kappaB activity and TRAIL-R2 receptor expression. Interestingly, IFN-beta-induced TRAIL-dependent apoptotic events strongly differ in the requirement of caspase activity. These results show that IFN-beta may induce an apoptotic response by deregulating cell cycle. Understanding the linkage between these mechanisms appears to be of primary importance in the search for new IFN-based therapeutic strategies to circumvent cancer disease or improve clinical outcome.

pRb2/p130 decreases sensitivity to apoptosis induced by camptothecin and doxorubicin but not by taxol

PURPOSE

In addition to their original function as cell cycle regulators, retinoblastoma (Rb) family members were recently reported to modulate the sensitivity of cancer cells to chemotherapeutic agents. The purpose of this study is to investigate the possible role of pRb2/p130 in the sensitivity of ovarian cancer to camptothecin, doxorubicin, and taxol.

EXPERIMENTAL DESIGN

pRb2/p130 was overexpressed in the CAOV-3 ovarian cancer cell line, and the effect of pRb2/p130 overexpression on sensitivity to apoptosis trigged by IC(50) doses of different drugs was evaluated by various methods, including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and Western blot analyses.

RESULTS

The results reported in this study support the conclusion that overexpression of pRb2/p130 in the CAOV-3 ovarian cancer cell line lacking wild-type p53 is able to inhibit apoptosis triggered by camptothecin and doxorubicin through the c-Jun NH(2)-terminal kinase signaling transduction pathway. Conversely, taxol-induced cell death is not influenced by the pRb2/p130 protein level.

CONCLUSIONS

A careful analysis of pRb2/p130 expression in tumor specimens could help to identify the best clinical protocol to be used for each patient, improving efficacy and tolerance and therefore offering additional progress in the treatment of advanced ovarian cancer.

Resveratrol-mediated sensitisation to TRAIL-induced apoptosis depends on death receptor and mitochondrial signalling

Natural food products such as resveratrol have gained considerable attention as cancer chemopreventive agents. In the present study, we investigated the potential of resveratrol to overcome the resistance of tumour cells against TRAIL. While resveratrol enhanced TRAIL-induced apoptosis through G1 cell cycle arrest and survivin depletion, resveratrol failed to sensitise cells with high expression levels of Bcl-2 or FADD-DN. Interestingly, overexpression of Bcl-2 or FADD-DN did not interfere with resveratrol-mediated cell cycle arrest or survivin depletion, but blocked release of cytochrome c and Smac from mitochondria into the cytosol, enhanced caspase activation and apoptosis upon combined treatment with resveratrol and TRAIL indicating that overexpression of Bcl-2 or FADD-DN decoupled the effect of resveratrol on the cell cycle and apoptosis. Similarly, cell cycle arrest at G1 using the cell cycle specific inhibitor mimosine or downregulation of survivin expression by antisense oligonucleotides failed to enhance TRAIL-induced apoptosis in Bcl-2- or FADD-DN-transfected cells. Likewise, inhibition of caspase activity using the broad range caspase inhibitor zVAD.fmk did not interfere with resveratrol-mediated cell cycle arrest and survivin depletion, while blocking apoptosis upon combined treatment with resveratrol and TRAIL. Thus, resveratrol is a potent sensitiser for TRAIL in certain tumours. However, it may be ineffective in others, e.g. in tumours with enhanced Bcl-2 expression or defective death receptor signalling.

High effectiveness of platinum(IV) complex with adamantylamine in overcoming resistance to cisplatin and suppressing proliferation of ovarian cancer cells in vitro

[(OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV)], coded as LA-12, is an octahedral platinum(IV) complex containing a bulky hydrophobic ligand - adamantylamine. The use of bulky hydrophobic amines as non-leaving ligands, may increase uptake of the compound by the cancer cells. Therefore, the effects of LA-12 on sensitive (A2780) and cisplatin resistant (A2780cis) ovarian cancer cell lines were investigated and compared to those of cisplatin. IC(50) and IC(90) concentrations of LA-12 were 6- (A2780) or 18-fold (A2780cis) lower than those for cisplatin (MTT assay). Equitoxic concentrations (IC(50) or IC(90)) of both compounds caused a significant and similar time- and dose-dependent inhibition of cell proliferation and an increase in the number of floating cells which corresponded to the decrease of total cell viability. A different type and dynamics of cell cycle perturbation after cisplatin and LA-12 treatment were detected. Exposure to LA-12 resulted in transient accumulation of A2780 and A2780cis cells in S phase, while cisplatin caused G(2)/M arrest in sensitive and S phase arrest in resistant cells. A relatively low rate of apoptosis after exposure to IC(50) or IC(90) of both complexes was observed, markedly higher in resistant A2780cis cells. Western blot analysis indicated a concentration-dependent p53 level increase in both lines (higher after cisplatin treatment). PARP cleavage was observed only in A2780cis cells. In conclusion, LA-12 was found to be significantly more efficient than cisplatin, and it was able to overcome the acquired cisplatin resistance (showing resistance factor 2.84-fold lower than those for cisplatin). In spite of the low rate of apoptosis, LA-12 caused increase of p53 level and cell cycle perturbations in the ovarian cancer cell lines studied.

Apigenin induced apoptosis through p53-dependent pathway in human cervical carcinoma cells

Apigenin is a widely distributed plant flavonoid and was proposed as an antitumor agent. In this study, we reported for the first time that apigenin inhibited the growth of human cervical carcinoma cells (HeLa) and through apoptotic pathway. The results showed that apigenin significantly decreased the viability of HeLa cells at 37-74 microM and the IC50 value was 35.89 microM. Apigenin-induced apoptosis in HeLa cells was confirmed by DNA fragmentation assay and induction of sub-G1 phase by flow cytometry. Apigenin-treated HeLa cells were arrested at G1 phase, which was associated with a marked increment of the expression of p21/WAF1 protein. The induction of p21/WAF1 appeared to be transcriptionally upregulated and was p53-dependent. In addition, apigenin induced Fas/APO-1 and caspase-3 expression which were also correlated with apoptosis. Apigenin decreased in the protein expression of Bcl-2 protein, which is an anti-apoptotic factor. The conclusion of this study is the apigenin induced p53 expression which caused cell cycle arrest and apoptosis. These findings suggest that apigenin has strong potential for development as an agent for preventing cervical cancer.

Sensitization for anticancer drug-induced apoptosis by the chemopreventive agent resveratrol

Current attempts to improve the survival of cancer patients largely depend on strategies to target tumor cell resistance. Naturally occurring dietary compounds such as resveratrol have gained considerable attention as cancer chemopreventive agents. Here, we report that resveratrol acts as potent sensitizer for anticancer drug-induced apoptosis by inducing cell cycle arrest, which in turn resulted in survivin depletion. Concomitant analysis of cell cycle and apoptosis revealed that pretreatment with resveratrol resulted in cell cycle arrest in S phase and apoptosis induction preferentially out of S phase upon subsequent drug treatment. Likewise, cell cycle arrest in S phase by cell cycle inhibitors enhanced drug-induced apoptosis. Resveratrol-mediated cell cycle arrest sensitized for apoptosis by downregulating survivin expression through transcriptional and post-transcriptional mechanisms. Similarly, downregulation of survivin expression using survivin antisense oligonucleotides sensitized for drug-induced apoptosis. Importantly, downregulation of survivin and enhanced drug-induced apoptosis by resveratrol occurred in various human tumor cell lines irrespective of p53 status. Thus, this combined sensitizer (resveratrol)/inducer (cytotoxic drugs) concept may be a novel strategy to enhance the efficacy of anticancer therapy in a variety of human cancers.

Sensitization for tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis by the chemopreventive agent resveratrol

Survivin is a member of the inhibitor of apoptosis proteins that is expressed at high levels in most human cancers and may facilitate evasion from apoptosis and aberrant mitotic progression. Naturally occurring dietary compounds such as resveratrol have gained considerable attention as cancer chemopreventive agents. Here, we discovered a novel function of the chemopreventive agent resveratrol: resveratrol is a potent sensitizer of tumor cells for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through p53-independent induction of p21 and p21-mediated cell cycle arrest associated with survivin depletion. Concomitant analysis of cell cycle, survivin expression, and apoptosis revealed that resveratrol-induced G(1) arrest was associated with down-regulation of survivin expression and sensitization for TRAIL-induced apoptosis. Accordingly, G(1) arrest using the cell cycle inhibitor mimosine or induced by p21 overexpression reduced survivin expression and sensitized cells for TRAIL treatment. Likewise, resveratrol-mediated cell cycle arrest followed by survivin depletion and sensitization for TRAIL was impaired in p21- deficient cells. Also, down-regulation of survivin using survivin antisense oligonucleotides sensitized cells for TRAIL-induced apoptosis. Importantly, resveratrol sensitized various tumor cell lines, but not normal human fibroblasts, for apoptosis induced by death receptor ligation or anticancer drugs. Thus, this combined sensitizer (resveratrol)/inducer (e.g., TRAIL) strategy may be a novel approach to enhance the efficacy of TRAIL-based therapies in a variety of human cancers.

Molecular mechanisms for apigenin-induced cell-cycle arrest and apoptosis of hormone refractory human prostate carcinoma DU145 cells

Development of effective agents for treatment of hormone-refractory prostate cancer has become a national medical priority. We have reported recently that apigenin (4',5,7-trihydroxyflavone), found in many common fruits and vegetables, has shown remarkable effects in inhibiting cell growth and inducing apoptosis in many human prostate carcinoma cells. Here we demonstrate the molecular mechanism of inhibitory action of apigenin on androgen-refractory human prostate carcinoma DU145 cells that have mutations in the tumor suppressor gene p53 and pRb. Treatment of cells with apigenin resulted in a dose- and time-dependent inhibition of growth, colony formation, and G1 phase arrest of the cell cycle. This effect was associated with a marked decrease in the protein expression of cyclin D1, D2, and E and their activating partner, cyclin-dependent kinase (cdk)2, 4, and 6, with concomitant upregulation of WAF1/p21, KIP1/p27, INK4a/p16, and INK4c/p18. The induction of WAF1/p21 and its growth inhibitory effects by apigenin appears to be independent of p53 and pRb status of these cells. Apigenin treatment also resulted in alteration in Bax/Bcl2 ratio in favor of apoptosis, which was associated with the release of cytochrome c and induction of apoptotic protease-activating factor-1 (Apaf-1). This effect was found to result in a significant increase in cleaved fragments of caspase-9, -3, and poly(ADP-ribose) polymerase (PARP). Further, apigenin treatment resulted in downmodulation of the constitutive expression of nuclear factor-kappaB (NF-kappaB)/p65 and NF-kappaB/p50 in the nuclear fraction that correlated with an increase in the expression of IkappaB-alpha (IkappaBalpha) in the cytosol. Taken together, we concluded that molecular mechanisms during apigenin-mediated growth inhibition and induction of apoptosis in DU145 cells was due to (1) modulation in cell-cycle machinery, (2) disruption of mitochondrial function, and (3) NF-kappaB inhibition.

Implication of mitochondrial involvement in apoptotic activity of fragile histidine triad gene: Application of synchronous luminescence spectroscopy

The fragile histidine triad (FHIT) tumor suppressor gene incorporates the common human chromosomal fragile site at 3p14.2. The structure and expression of the FHIT gene are frequently altered in many cancers. The tumor suppressor activity of the FHIT gene has been previously demonstrated as potentially involving apoptotic induction. Here, mitochondria are implicated as being involved in the apoptotic activity of the FHIT gene. A number of morphological and biochemical events, including the disruption of the inner mitochondrial transmembrane potential (Delta Psi(m)) and the release of apoptogenic cytochrome c protein into the cytoplasm, are characteristic features of the apoptotic program. The proapoptotic activity of the FHIT gene is studied by investigating the loss of Delta Psi(m) in mitochondria and translocation of cytochrome c. Synchronous luminescence (SL) spectroscopy is applied to measure mitochondrial incorporation of rhodamine 123 for direct analysis of alterations in the mitochondrial Delta Psi(m). The SL methodology is based on synchronous excitation in which the excitation and emission wavelengths are scanned simultaneously while a constant wavelength interval is maintained between the excitation and emission monochromators. An enhanced collapse of Delta Psi(m) in apoptotically induced FHIT expressing cells compared to FHIT negative cells is observed. The loss of Delta Psi(m) is greatly restricted in the presence of the apoptotic inhibitor, cyclosporin A. Cytoplasmic translocation of cytochrome c in the FHIT expressing cells as an early event in apoptosis is also demonstrated. It is concluded that Fhit protein expression maintained apoptotic function by altering the Delta Psi(m) and by enhancing cytochrome c efflux from the mitochondria.

New method for the analysis of cell cycle-specific apoptosis

BACKGROUND

In this study, a new method for the analysis of cell cycle specificity of apoptosis was designed by using a modified annexin V and propidium iodide (API) method.

METHODS

Cells of the human promyelocytic HL-60 line treated with camptothecin (CPT) or ultraviolet light (UV) were labeled with fluorescein isothiocyanate-conjugated annexin V and prefixed with 1% methanol-free formaldehyde on ice, and their DNA was stained stoichiometrically with propidium iodide in the presence of digitonin. Cellular green and red fluorescences were measured by flow cytometry.

RESULTS

Cell cycle specificity of apoptosis obtained by the API method and those analyzed for the presence of DNA strand breaks by using terminal deoxynucleotidyl transferase (TdT) assay were similar: CPT- or UV-induced apoptosis preferentially in S- or G1-phase cells, respectively. When the internucleosomal DNA degradation was prevented by the serine protease inhibitor N-tosyl-L-phenylalanine chloromethyl ketone, apoptotic cells could not be detected by the TdT assay but were identified by the API method.

CONCLUSIONS

The API method, similar to the TdT assay, accurately detects the cell cycle phase specificity of apoptosis. Also, the API method appears to detect earlier stages of apoptosis than the TdT assay.

Antiproliferative Effect of Resveratrol in Human Prostate Carcinoma Cells

Resveratrol, a polyphenolic phytoalexin found in grapes, may have potential for the prevention and treatment of human cancer. We report here that resveratrol inhibits the growth of human prostate carcinoma DU145 cells and provide a molecular explanation of the effect. Resveratrol treatment in DU145 cells resulted in a dose-dependent inhibition of cell growth and induced apoptotic cell death. The antiproliferative effect of resveratrol was associated with the inhibition of D-type cyclins and cyclin-dependent kinase (Cdk) 4 expression, and the induction of tumor suppressor p53 and Cdk inhibitor p21. Moreover, the kinase activities of cyclin E and Cdk2 were inhibited by resveratrol without alteration of their protein levels. Resveratrol treatment also up-regulated the Bax protein and mRNA expression in a dose-dependent manner; however, Bcl-2 and Bcl-xL levels were not significantly affected. These effects were found to correlate with an activation of caspase-3 and caspase-9. Taken together, our study suggests that resveratrol has a strong potential for development as an agent for the prevention of human prostate cancer.

Cell cycle regulation and neural differentiation

The general mechanisms that control the cell cycle in mammalian cells have been studied in depth and several proteins that are involved in the tight regulation of cell cycle progression have been identified. However, the analysis of which molecules participate in cell cycle exit of specific cell lineages is not exhaustive yet. Moreover, the strict relation between cell cycle exit and induction of differentiation has not been fully understood and seems to depend on the cell type. Several in vivo and in vitro studies have been performed in the last few years to address these issues in cells of the nervous system. In this review, we focus our attention on cyclin-cyclin-dependent kinase complexes, cyclin kinase inhibitors, genes of the retinoblastoma family, p53 and N-Myc, and we aim to summarize the latest evidence indicating their involvement in the control of the cell cycle and induction of differentiation in different cell types of the peripheral and central nervous systems. Studies on nervous system tumors and a possible contributory role in tumorigenesis of polyomavirus T antigen are reported to point out the critical contribution of some cell cycle regulators to normal neural and glial development.

Cell cycle and apoptosis

Apoptosis and proliferation are intimately coupled. Some cell cycle regulators can influence both cell division and programmed cell death. The linkage of cell cycle and apoptosis has been recognized for c-Myc, p53, pRb, Ras, PKA, PKC, Bcl-2, NF-kappa B, CDK, cyclins and CKI. This review summarizes the different functions of the proteins presently known to control both apoptosis and cell cycle progression. These proteins can influence apoptosis or proliferation but different variables, including cell type, cellular environment and genetic background, make it difficult to predict the outcome of cell proliferation, cell cycle arrest or cell death. These important decisions of cell proliferation or cell death are likely to be controlled by more than one signal and are necessary to ensure a proper cellular response.

A simple, informative, and quantitative flow cytometric method for assessing apoptosis in cultured cells

Described herein is a method for assessing apoptosis in tissue culture cells that is facile, highly informative, readily quantifiable, and generally applicable. As in conventional DNA-based flow cytometric analysis, the approach utilizes fixed, propidium iodide-stained cells. However, this particular application employs correlated two-parameter analyses of log(10)DNA fluorescence signals versus log(10) side-scatter (SS) signals of cells undergoing apoptosis. The features and the advantages of this approach, which provides substantially more information than is otherwise available from conventional analysis, are demonstrated in experiments monitoring the effects of the antineoplastic agents cisplatinum (cisP) and camptothecin (CAM) on a variety of cultured cell types, including epithelial cells (SW480; human colon carcinoma), fibroblasts (rat2 and 3T3; normal fibroblast lines), and cells of myeloid origin (CCRF-CEM; human leukemia). The utility of the technique is demonstrated further in a series of experiments with the histidine analogue L-histidinol. These experiments reveal that L-histidinol is pro-apoptotic in CCRF-CEM cells, accentuates markedly the apoptotic response otherwise elicited by CAM in murine B16f10 melanoma cells and inhibits CAM-induced apoptosis in normal 3T3 fibroblasts.

The circadian gene Period2 plays an important role in tumor suppression and DNA damage response in vivo

The Period2 gene plays a key role in controlling circadian rhythm in mice. We report here that mice deficient in the mPer2 gene are cancer prone. After gamma radiation, these mice show a marked increase in tumor development and reduced apoptosis in thymocytes. The core circadian genes are induced by gamma radiation in wild-type mice but not in mPer2 mutant mice. Temporal expression of genes involved in cell cycle regulation and tumor suppression, such as Cyclin D1, Cyclin A, Mdm-2, and Gadd45alpha, is deregulated in mPer2 mutant mice. In particular, the transcription of c-myc is controlled directly by circadian regulators and is deregulated in the mPer2 mutant. Our studies suggest that the mPer2 gene functions in tumor suppression by regulating DNA damage-responsive pathways.

Surrogate endpoints in cancer drug development

Over the next three years a large number of novel, mechanistically targeted drugs will enter clinical trials for cancer. The remarkable progress in understanding the molecular biology of cancer has provided an enormous range of validated targets for drug discovery. Following lead optimisation and suitable pharmaceutical formulation these compounds have undergone rapid screening in preclinical models. Innovative methods of clinical development are now essential to ensure optimal dose determination and scheduling. The discovery of novel surrogates for efficacy is essential in this fast moving area and requires imaginative partnerships between academic groups and the pharmaceutical industry.

Interview with the retinoblastoma family members: do they help each other?

The ultimate destiny of a cell to undergo division, differentiation, survival, and death results from an intricate balance between multiple regulators including oncogenes, tumor suppressor genes, and cell cycle associated proteins. Deregulation of the cell cycle machinery switches the phenotype from a normal cell to a cancerous cell. Fundamental alterations of tumor suppressor genes may result in an unregulated cell cycle with the accumulation of mutations and eventual neoplastic transformation. As such, one may define cancer as a genetic disease of the cell cycle. In this review, we will emphasize our current understanding of how the cell cycle machinery maintains cellular homeostasis by studying the consequences of its deregulation.

Involvement of nuclear factor-kappa B, Bax and Bcl-2 in induction of cell cycle arrest and apoptosis by apigenin in human prostate carcinoma cells

Apigenin, a common dietary flavonoid abundantly present in fruits and vegetables, may have the potential for prevention and therapy for prostate cancer. Here, we report for the first time that apigenin inhibits the growth of androgen-responsive human prostate carcinoma LNCaP cells and provide molecular understanding of this effect. The cell growth inhibition achieved by apigenin treatment resulted in a significant decrease in AR protein expression along with a decrease in intracellular and secreted forms of PSA. These effects were also observed in DHT-stimulated cells. Further, apigenin treatment of LNCaP cells resulted in G1 arrest in cell cycle progression which was associated with a marked decrease in the protein expression of cyclin D1, D2 and E and their activating partner cdk2, 4 and 6 with concomitant induction of WAF1/p21 and KIP1/p27. The induction of WAF1/p21 appears to be transcriptionally upregulated and is p53 dependent. In addition, apigenin inhibited the hyperphosphorylation of the pRb protein in these cells. Apigenin treatment also resulted in induction of apoptosis as determined by DNA fragmentation, PARP cleavage, fluorescence microscopy and flow cytometry. These effects were found to correlate with a shift in Bax/Bcl-2 ratio more towards apoptosis. Apigenin treatment also resulted in down-modulation of the constitutive expression of NF-kappaB/p65. Taken together, these findings suggest that apigenin has strong potential for development as an agent for prevention against prostate cancer.

Gene expression profiles in the Peyronie's disease plaque

OBJECTIVES

To provide molecular insight into the pathophysiology of Peyronie's disease (PD), a preliminary profile of differential gene expression between the PD plaque and control tunica albuginea was obtained with DNA microarrays.

METHODS

Seven PD plaques and five control tunica albugineas were studied. cDNA specimens were prepared from RNA isolated from one calcified PD plaque and one control tissue and hybridized with the Clontech Atlas 1.2 Array. Another set of plaque and control RNA samples was hybridized with the Affymetrix GeneChip. Relative changes of greater than 2.0 defined up-regulation and down-regulation, respectively. RNA from the remaining tissues was used to determine, by reverse transcriptase-polymerase chain reaction and Western blot analysis, the expression of selected individual genes.

RESULTS

Some of up-regulated genes in the PD plaque detected by the Clontech assay were pleiotrophin, monocyte chemotactic protein 1, and early growth response protein, which are involved in osteoblast recruitment, inflammation, and fibroblast proliferation, respectively. Ubiquitin and Id-2, which are involved in tissue remodeling, were down-regulated. The Affymetrix DNA chips identified the up-regulation of elastase (involved in elastic fiber degradation) and the myofibroblast markers alpha and gamma-smooth muscle actin, desmin, and others, as well as the down-regulation of collagenase IV and transforming growth factor-beta modulators. Four of the five genes selected for reverse transcriptase-polymerase chain reaction and Western blotting confirmed the DNA microarray results.

CONCLUSIONS

In the PD tissue, the genes involved in collagen synthesis, myofibroblast differentiation, tissue remodeling, inflammation, ossification, and proteolysis are up-regulated, and the genes that inhibit some of these processes and collagenase are down-regulated.