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Nidus vespae protein inhibiting proliferation of HepG2 hepatoma cells through extracellular signal-regulated kinase signaling pathways and inducing G1 cell cycle arrest

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Abstract

A protein named NVP(1) was isolated from Nidus vespae. The aim of the present study was to elucidate whether and how NVP(1) modulates the proliferation of HepG2 cells. NVP(1) at a concentration of 6.6 microg/ml could arrest the cell cycle at stage G1 and inhibit the mRNA expression of cyclinB, cyclinD1 and cyclinE. NVP(1) suppressed cdk2 protein expression, but increased p27 and p21 protein expression. However, NVP(1) did not alter p16 protein expression levels. NVP(1) promoted apoptosis in HepG2 cells as indicated by nuclear chromatin condensation, and in addition, the extracellular signal-regulated kinase (ERK) signaling pathway was activated. Moreover, the p-ERK protein expression level was attenuated when the HepG2 cells were pretreated with ERK inhibitor PD98059. These results demonstrate that NVP(1) inhibits proliferation of HepG2 through ERK signaling pathway. NVP(1) could be a potential drug for liver cancer.

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... Nidus Vespae has been used in TCM for thousands of years to treat many diseases, including rheumatoid arthritis, digestive and urinary disorders, dental diseases, and cancer [14,19,20]. Nidus Vespae has strong anti-inflammatory and antibacterial effects [15,16,21] and also exerts antitumor [22][23][24] and immunomodulatory effects [18,25]. Many studies have confirmed that tumorigenesis and development are closely related to immunity and inflammation, and we speculate that Nidus Vespae may have multiple beneficial effects in the context of tumor treatment. ...
... PI staining showed that the number of cells in the G2/M stage was increased by NVC treatment, suggesting that the cell cycle was arrested. Research on the antitumor effects of Nidus Vespae has mainly focused on Nidus Vespae protein [22,23,26]. However, proteins are often inactivated during the high-temperature cooking process, so there will likely be other high-temperature resistant anticancer active ingredients in NVD. ...
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Objective: The aim of this study was to investigate the in vitro antitumor effects of Nidus Vespae on gastric cancer and its ability to promote immune function. Methods: Cell viability was detected by the Cell Counting Kit-8 (CCK-8) assay. Cell cycle distribution and apoptosis were detected using flow cytometry. The THP-1 human monocytic cell line was used as a source of monocytic effector cells for analyzing proliferation and dendritic cell (DC) induction. Enzyme-linked immunosorbent assay was used to detect cytokine production, and multicolor flow cytometry was used to study the phenotype and functionality of THP-1 DCs. Results: A high concentration (>10 mg/mL) of Nidus Vespae decoction (NVD) inhibited SGC-7901 gastric cancer cell growth by inducing G2/M cell cycle arrest and apoptosis. However, a low concentration (≤10 mg/mL) of NVD significantly increased the proliferative ability of THP-1 in serum-containing medium and caused an increase in dendritic protrusions with the typical morphology of DCs compared to the negative control in serum-free medium. The THP-1 DCs had significantly increased expression of cluster of differentiation 11c (CD11c), CD40, CD80, CD83, and CD86, as well as secretion of tumor necrosis factor-alpha. Furthermore, the supernatant of THP-1 DCs significantly inhibited the proliferation of gastric cancer cells by inducing apoptosis and G1/S cell cycle arrest. Conclusions: Our findings suggest that NVD not only directly inhibits the growth of gastric cancer cells but also exerts indirect antitumor effects by enhancing immune function. These results provide an important theoretical basis for the clinical application of Nidus Vespae in gastric cancer treatment.
... The antibiotic properties of wasp venom, larval secretions (e.g. Turillazzi et al., 2004;Herzner et al., 2013;Moreau, 2013) and nest materials have long been recognised, with use in historic and contemporary folk medicine (Wang et al., 2008a). The venom of solitary and social wasps has antimicrobial properties. ...
... (2021) Finally, wasp products have a history of use in traditional medicine. For instance, quinone 7,8-seco-para-ferruginone isolated from the nests of Vespa simillima exhibits potent inhibition of rat hepatoma cells (Fujiwara et al., 2008); the peptide Nidus Vespa Protein 1 found in nest comb collected from a variety of social wasps including Polistes olivaceous, P. japonicus and Parapolybia varia promotes apoptosis and inhibits the proliferation of hepatoma cells, implicating its potential as a future treatment for liver cancer (Wang et al., 2008a). Nest comb components also show potential as a novel oral anti-microbial, reducing the biofilm capabilities of Streptococcus mutans (a bacterium heavily associated with dental plaque and decay) (Xiao et al., 2007;Guan et al., 2012). ...
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The aculeate wasps are one of the most diverse and speciose insect taxa; they are omnipresent across ecosystems and exhibit diverse co-evolutionary and exploitative associations with other organisms. There is widespread conjecture that aculeate wasps are likely to perform essential ecological and economic services of importance to the health, well-being and nutritional needs of our planet. However, the scope and nature of the ecosystem services they provide are not well understood relative to other insect groups (e.g. bees, butterflies, beetles); an appreciation of their value is further tarnished by their public reputation as pointless pests. Here, we conduct the first comprehensive review of how aculeate wasps contribute to the four main areas of ecosystem services: regulatory, provisioning, supporting and cultural services. Uniting data from a large but previously disconnected literature on solitary and social aculeate wasps, we provide a synthesis on how these insects perform important ecosystem services as parasites, predators, biological indicators, pollinators, decomposers and seed dispersers; and their additional services as a sustainable alternative to meat for human consumption , and medicinal potential as sources of research leads for anti-microbials and cancer treatments. We highlight how aculeate wasps offer substantial, but largely overlooked, economic benefits through their roles in natural pest management and biological control programs. Accordingly, we provide data-driven arguments for reasons to consider the ecosystem service value of aculeate wasps on a par with other 'useful' insects (e.g. bees). Finally, we provide a research roadmap identifying the key areas of research required to capitalise better on the services provided by these important insects.
... Cyclin E, Cyclin B and CCND1, which bind cyclin-dependent protein kinases (Cdk) to control cell cycle progression, such as G1-S and G2-M transition, are expressed during the course of the cell cycle (52)(53)(54). By contrast, as a Cdk inhibitor, p21 can bind and inactivate Cdk-cyclin complexes to repress specific steps of cell cycle progression (55)(56)(57). The results of the present study demon-strated that miR-23a-5p positively regulate the expression levels of these genes during C2C12 myoblast proliferation. ...
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Skeletal myogenesis is a highly ordered and complex biological process that is mediated by numerous regulatory factors. In previous studies, it has been demonstrated that microRNAs (miRs) and long non‑coding RNAs (lncRNAs) serve key roles in skeletal myogenesis. The present study showed that the expression levels of miR‑23a‑5p showed a dynamic change from decrease to increase during C2C12 myoblast proliferation and differentiation. Functional analysis using 5‑ethynyl‑2'‑deoxyuridine proliferation and Cell Counting Kit‑8 detection assays indicated that overexpression of miR‑23a‑5p significantly promoted C2C12 myoblast proliferation compared with the negative control. In addition, in C2C12 myoblasts transfected with miR‑23a‑5p mimics, increased expression levels of regulators associated with cell proliferation (Cyclin E, CCND1 and Cyclin B) were observed compared with the negative control. By contrast, overexpression of miR‑23a‑5p decreased the expression levels of specific‑myogenesis factors (MyoD, MyoG and Myf5) and decreased C2C12 myoblast differentiation. Luciferase activity assays indicated that miR‑23a‑5p suppressed the luciferase activity of lncDum. Further analysis demonstrated that miR‑23a‑5p not only showed an opposite expression level pattern compared with lncDum, which was first increased and then decreased, but also had an opposite effect on the proliferation and differentiation of C2C12 myoblasts compared with lncDum which inhibited cell proliferation and promoted cell differentiation. Taken together, these results indicated that miR‑23a‑5p may mediate the proliferation and differentiation of C2C12 myoblasts, which may be involved in lncDum regulation.
... In Korea, nests of social wasps have also been used as ingredients in traditional liquor for a long time, as they are thought to promote human health . Based on the available ethnopharmacological evidence, numerous studies have been carried out to determine the antimicrobial (Guan et al. 2012), anti-inflammatory (He et al. 2011), HepG2 hepatoma cell antiproliferation (Wang et al. 2008), skin-whitening (Cha et al. 2017), and immunomodulatory (Zhu et al. 2015) effects of Nidus vespae. The inhibitory effects against the oral cariogenic bacterium Streptococcus mutans have been most widely investigated, along with the anti-acidogenetic (Xiao et al. 2006), antibiofilm (Xiao et al. 2007), and bacteriostatic activities (Guan et al. 2012). ...
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The yellow‐legged hornet, Vespa velutina nigrithorax, is an invasive social wasp found in temperate regions and is recognized as a hazardous insect, as it often attacks humans and honeybees. Nidus vespae (nests of social wasps) are traditionally used as a medicinal ingredient; thus, V. v. nigrithorax may be useful as a biological resource. Extracts of Nidus vespae built by V. v. nigrithorax were examined for their antibacterial activity screening against six food‐borne pathogenic bacteria, and the ethyl acetate and butanol layer of the extract exhibited inhibitory activity against the pathogenic bacteria. We determined the antibacterial activity of Nidus vespae built by V. v. nigrithorax for the first time.
... 21 The authors observed that Ruyiping treatment significantly downregulated the expression of CDK1 and cyclin B1, providing a molecular-level explanation for Ruyipingtriggered cell cycle arrest at the G2 phase in breast cancer cells. As the active components of nidus vespae, nidus vespae protein named NVP (1) has been reported to inhibit cell proliferation and induce cell cycle arrest in HepG2 cells by downregulating the expression of cyclin B1. 22 Wang et al. found that curcumol, the active component of Curcuma zedoaria, decreases the proliferation of colorectal cancer LoVo cells through regulating the p38 MAPK signaling pathway. 23 Curcumol also induces cell cycle arrest at the G0/G1 phase via the downregulation of Akt/GSK3b/cyclin D1 pathways. ...
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... Bengalin increased autophagy markers such as Beclin-1, Atg12, Atg7, Atg5, and Atg3 in U937 cells [151]. Another peptide NVP(1), a 6.6 kDa of molecular weight isolated from the venom of Wasp Nidus vespae [152], is also known to interact with MAPK signaling cascade. NVP(1) induced cell cycle arrest in HepG2 hepatoma cells and inhibited the mRNA expression of cyclin B, cyclin D1, and cyclin E. NVP (1) was observed to cause nuclear chromatin condensation of HepG2 cells and activation of ERK1/2 to induce apoptosis. ...
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... Curcuma longa Linn was found to have beneficial effects on the early and late stages of pathogenesis by upregulating the p21 and p57 protein level, thus preventing and delaying carcinogenesis [52,53]. A protein from Nidus vespae could also arrest the cell cycle at stage G1 and inhibit the mRNA expression of cyclin B, cyclin D1 and cyclin E. It suppressed cdk2 expression, but increased p27 and p21 protein expression, thus promoting apoptosis and hence has been identified as a potential drug for cancer treatment [54]. D. Activation of body's own immune system against transformed cells NK cells are a part of the innate immune system which play a vital role in defense against pathogen infected or transformed cells. ...
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... NVP(1) increased p27 and p21 protein expression, but suppressed cdk2 protein expression. The extracellular signal-regulated kinase (ERK) signaling pathway was activated, indicating that NVP(1) inhibits proliferation of HepG2 through ERK signaling pathway, through activation of p27 e p21 and reduction of cdk2 expression (Wang et al., 2008a). ...
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Many active principles produced by animals, plants and microorganisms have been employed in the development of new drugs to treat diseases such as cancer. Among the animals that produce pharmacologically active molecules capable of interfering in human cellular physiology, the highlights are venomous arthropods, such as scorpions, bees, wasps, spiders, ants and caterpillars. The substances found in the venom of these animals present great potential as anti-tumor agents. In this review, we present the main results of years of research involving the active compounds of arthropods venoms that have anti-cancer activity.
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During fetal mouse development, germ cells enter the developing gonad at embryonic day (E) 10–11. In response to signaling from the male or female gonad, the germ cells commit either to spermatogenesis at E12.5 and enter mitotic arrest or to oogenesis and enter meiotic arrest at E13.5. It is unclear whether male commitment of the germ line and mitotic arrest are directly associated or whether they are developmentally separate. In addition, the published data describing the timing of mitotic arrest are inconsistent, and the molecular processes underlying the control of the cell cycle during mitotic arrest also remain unknown. Using flow cytometric techniques, 5-bromo-2′-deoxyuridine labeling, and immunofluorescent analysis of cell proliferation, we have determined that germ cells in the embryonic mouse testis arrest in G0 during E12.5 and E14.5. This process is gradual and occurs in an unsynchronized manner. We have also purified germ cells and analyzed molecular changes in male germ cells as they exit the cell cycle. This has allowed us to identify a series of molecular events, including activation of p27Kip1, p15INK4b, and p16INK4a; the dephosphorylation and degradation of retinoblastoma protein; and the suppression of CyclinE, which lead to mitotic arrest. For the first time, the data presented here accurately define the mitotic arrest of male germ cells by directly combining the analysis of cell cycle changes with the examination of functionally defined cell cycle regulators. Disclosure of potential conflicts of interest is found at the end of this article.
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Disruption of pRB-E2F interactions by E1A is a key event in the adenoviral life cycle that drives expression of early viral transcription and induces cell cycle progression. This function of E1A is complicated by E2F1, an E2F family member that controls multiple processes besides proliferation, including apoptosis and DNA repair. Recently, a second interaction site in pRB that only contacts E2F1 has been discovered, allowing pRB to control proliferation separately from other E2F1-dependent activities. Based on this new insight into pRB-E2F1 regulation, we investigated how E1A affects control of E2F1 by pRB. Our data reveal that pRB-E2F1 interactions are resistant to E1A-mediated disruption. Using mutant forms of pRB that selectively force E2F1 to bind through only one of the two binding sites on pRB, we determined that E1A is unable to disrupt E2F1's unique interaction with pRB. Furthermore, analysis of pRB-E2F complexes during adenoviral infection reveals the selective maintenance of pRB-E2F1 interactions despite the presence of E1A. Our experiments also demonstrate that E2F1 functions to maintain cell viability in response to E1A expression. This suggests that adenovirus E1A's seemingly complex mechanism of disrupting pRB-E2F interactions provides selectivity in promoting viral transcription and cell cycle advancement, while maintaining cell viability.
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It has been reported that lipiodol solution of Re-188-labeled 2,2,9,9-tetramethyl-4,7-diaza-1,10-decanedithiol (TDD), an N2S2 derivative, shows excellent targeting of liver cancer after transhepatic arterial embolization (TAE). However, its tumor retention is not high enough to treat liver cancer. Therefore, a new form of TDD, 4-hexadecyl-TDD (HDD), was developed to improve tumor retention by introducing a long alkyl chain. In this study, we compared the tumor retention properties of Re-188-HDD/lipiodol and Re-188-TDD/lipiodol, using a rabbit liver cancer model, and performed dosimetry using the results. Methods: The VX2 cancer cell line was implanted into the livers of 7 rabbits. TAE was performed on 3 rabbits with Re-188-TDD/lipiodol and on 4 rabbits with Re-188-HDD/lipiodol, and conjugated anterior and posterior planar scans were obtained at 1, 2, 6, 24, and 48 h after TAE. From these images, tumor retention was calculated and compared between Re-188-TDD and Re-188-HDD. Afterward, the required dose of radioactivity and the radiation dosimetry for exposure of major organs were calculated using MIRDOSE3.1 software. Results: The residence times of radioactivity in the liver were 10.2 +/- 1.0 h in the Re-188-TDD group and 17.6 +/- 0.8 h in the Re-188-HDD group (P = 0.034). The required radioactivity for 100 Gy of irradiation to 2.64- to 5.27-cm tumors was 142-1,070 MBq of Re-188-HDD in the rabbit model. The radiation exposures for the major organs were within the tolerable range, and the S-value for the whole body (effective dose equivalent) was calculated to be 0.209 mSv/MBq. Conclusion: Introduction of a long alkyl chain significantly improved the tumor retention of Re-188-HDD/lipiodol, compared with that of Re-188-TDD/lipiodol. Moreover, the required radioactivity for humans and the radiation exposure were within the feasible range for clinical application.
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Estrogens induce cell proliferation in target tissues by stimulating progression through G(1) phase of the cell cycle, but the underlying molecular targets remain undefined, To determine the role of the cyclin/cyclin-dependent kinase (CDK)/retinoblastoma protein (pRB) pathway in this response we treated MCF-7 breast cancer cells with the pure estrogen antagonist ICI 182780 to inhibit estrogen-induced gene expression and induce G(1) phase arrest, Subsequent treatment with 17 beta-estradiol resulted in the synchronous entry of cells into S phase commencing at 12 h, The proportion of cells in S phase reached a maximum of 60% at 21-24 h, Cells subsequently completed mitosis and entered a second semi-synchronous round of replication. Entry into S phase was preceded by increased activity of both Cdk4 and cyclin E-Cdk2 and hyperphosphorylation of pRB, all within the first 3-6 h of estradiol treatment, The increase in Cdk4 activity was accompanied by increases in cyclin D1 mRNA and protein, indicating that an initiating event in the activation of Cdk4 was increased cyclin D1 gene expression, In contrast, the levels of Cdk2 and the CDK inhibitors p21 (WAF1/CIP1/SDI1) and p27 (KIP1) in total cell lysates and in cyclin E immunoprecipitates were unaltered at these early time points. However, an inhibitory activity was present in antiestrogen-pretreated cell lysates toward recombinant cyclin E-Cdk2 and was relieved by estradiol treatment, This activity was attributable predominantly to p21, These apparently conflicting data were resolved by performing gel filtration chromatography, which revealed that only a minority of cyclin E-Cdk2 complexes were active following estradiol treatment, Active complexes eluted at a higher molecular weight than inactive complexes, were relatively deficient in both p21 and p27, and contained Cdk2 with increased threonine 160 phosphorylation, consistent with a mechanism of activation of cyclin E-Cdk2 involving both reduced CDK inhibitor association and CDK-activating kinase-mediated phosphorylation of Cdk2, These results provide an explanation for the early activation of both cyclin D1-Cdk4 and cyclin E-Cdk2 complexes that accompany G(1)-S phase progression in response to estradiol.
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Herbal poisoning exposures reported to poison centers increased by 344% after passage of the Dietary Supplement Health and Education Act, with 24412 exposures reported in 2003. Increased toxicity is speculated to be related to lack of child-resistant packaging, new issues of contamination, proliferation of multiple ingredient products, excessive concentration of active ingredients, and discovery of new drug-herb interactions. This review addresses contamination issues such as heavy metals, pharmaceuticals, homeopathic remedies, microbes, insects, environmental chemicals, and mis-identification of one plant for another. Toxicity issues covered include carcinogenicity, delay in seeking medical treatment when using herbs to treat serious illness, toxic components, hypersensitivity reactions, hepatotoxins, nephrotoxins, epileptogenic compounds, cardiac toxins, gastrointestinal toxins, and hematologic toxins. Common drug-herb interactions are discussed. The pharmacist plays an important role in patient education and evaluation of potential toxicities related to herbal supplements.
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Multiple growth factors can stimulate quiescent vascular smooth muscle cells to exit from G0 and reenter the cell cycle. The macrolide antibiotic rapamycin, bound to its cytosolic receptor FKBP, is an immunosuppressant and a potent inhibitor of cellular proliferation. In the present study, the antiproliferative effects of rapamycin on human and rat vascular smooth muscle cells were examined and compared with the effects of a related immunosuppressant, FK520. In vascular smooth muscle cells, rapamycin, at concentrations as low as 1 ng/mL, inhibited DNA synthesis and cell growth. FK520, an analogue of the immunosuppressant FK506, is structurally related to rapamycin and binds to FKBP but did not inhibit vascular smooth muscle cell growth. Molar excesses of FK520 blocked the antiproliferative effects of rapamycin, indicating that the effects of rapamycin required binding to FKBP. Rapamycin-FKBP inhibited retinoblastoma protein phosphorylation at the G1/S transition. This inhibition of retinoblastoma protein phosphorylation was associated with a decrease in p33cdk2 kinase activity. These observations suggest that rapamycin, but not FK520, inhibits vascular smooth muscle cell proliferation by reducing cell-cycle kinase activity.
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Rapamycin (RPM) is a potent and effective immunosuppressant which we have shown previously to inhibit intimal thickening in rat allograft and balloon-injured arteries. In this report, we have examined the effects of RPM on growth factor-induced vascular smooth muscle cell (VSMC) DNA synthesis. RPM potently inhibited platelet-derived growth factor (PDGF) (IC50 = 5 x 10(-9) M) and basic fibroblast growth factor (bFGF) (IC50 = 8 x 10(-10) M)-induced VSMC DNA synthesis. In contrast, only the highest concentrations of FK506 and CsA significantly altered PDGF- or bFGF-induced VSMC DNA synthesis. Addition of RPM (10(-9) M) at as late as 46 hr after growth factor addition still effectively suppressed bFGF- or PDGF-induced DNA synthesis by 76% and 54%, respectively. The extent of the antagonism of RPM's inhibition of bFGF-induced VSMC DNA synthesis by FK506 was inversely proportional to RPM concentration and directly proportional to FK506 concentration.
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On the basis of current knowledge, control of the G1/S phase transition is largely a matter of regulating a set of specific cyclin dependent kinase (CDK) activities. In mammalian cells, the G1/S specific CDK activities are composed of complexes between D type cyclins and either CDK4 or CDK6 and between cyclin E (and possibly cyclin A) and CDK2. A variety of internal and external signals regulate G1/S specific CDKs by modulating cyclin availability, the levels of CDK inhibitory proteins and the phosphorylation status of CDKs. Although much is now known about the regulation of G1/S specific CDKs, the only well characterized substrate to date is the retinoblastoma gene product, RB. Phosphorylation of RB by CDKs neutralizes its cell cycle inhibitory properties, allowing progression of G1 to S phase. Not surprisingly, many components of the cell cycle regulatory machinery, including CDKs, CDK inhibitors and CDK substrates, are important targets of mutations that lead to human malignancy.
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Cancer cells are known to display up-regulation of ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC), the key enzymes in the biosynthesis of polyamines that are essential for cellular proliferation. We have shown previously that overexpression of ODC or AdoMetDC alone can induce tumorigenic transformation of rodent fibroblasts. Because the subversion of normal cell cycle control is thought to be a crucial event in cancer development, we examined ODC- and AdoMetDC-transformed fibroblasts for alterations in the cell cycle components. The level of cyclin D1 and cyclin D1-dependent kinase and total cyclin-dependent kinase (CDK) 4 activities were elevated in the ODC transformants and particularly in the AdoMetDC transformants. Cyclin E content was not elevated, but a moderate increase in cyclin E-dependent kinase activity was seen in both cells. Total CDK2 activity was increased only in the ODC-transformed cells. The amount of the p27Kip1 CDK inhibitor was greatly decreased in both transformants. Nevertheless, p27Kip1 was present in the active cyclin D1/CDK4 complexes in the cells but absent from the cyclin E/CDK2 complexes. Restoration of p27Kip1 expression in the ODC- and AdoMetDC-transformed cells by transfection resulted in growth inhibition, but not in morphological reversion. An elevation in the level of hyperphosphorylated retinoblastoma protein was observed mainly in the ODC-transformed cells. These results suggest that the expression of ODC or AdoMetDC may affect cell cycle regulation in many ways. However, the largest common effect, which is therefore potentially relevant to some aspects of transformation, appears to be the constitutive down-regulation of p27Kip1 and its loss from the cyclin/CDK2 complexes.
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Microtubules are highly dynamic cellular polymers made of alphabeta-tubulin and associated proteins. They play a key role during mitosis, participating in the exact organization and function of the spindle, and are critical for assuring the integrity of the segregated DNA. Therefore, they represent one of the more effective targets in current cancer therapy. Paclitaxel (Taxol) is the prototype of the taxane family of antitumor drugs, and it was the first natural product shown to stabilize microtubules. This unique mechanism of action is in contrast to other microtubule poisons, such as Vinca alkaloids, colchicine, and cryptophycines, which inhibit tubulin polymerization. Taxanes block cell cycle progression through centrosomal impairment, induction of abnormal spindles and suppression of spindle microtubule dynamics. Triggering of apoptosis by aberrant mitosis or by subsequent multinucleated G1-like state related to mitotic slippage, depends on cell type and drug schedule. The development of fluorescent derivatives of paclitaxel led us to locate spindle pole microtubules and centrosomes as main sub-cellular targets of cytotoxic taxoids in living cells. In this review we discuss these findings in the context of a cell cycle-dependent response to taxanes, based on the cellular targets, and the status of the implicated cell cycle checkpoints. We also review those events that can influence this response, like the different signal transduction pathways activated/inactivated in relation to Bcl-2 phosphorylation and induction of apoptosis, and the controversial role of the p53 status on cell sensitivity to paclitaxel. Finally, cell cycle-dependent resistance, an emerging concept in combination sequential chemotherapy, is discussed on the basis of the cell cycle-dependent mechanisms of action of taxanes.
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Tanshinone (Tan) is one of the active components of Radix Salvia miltiorrhiza (Lamiaceae), which is clinically used to treat cardiovascular diseases in China. The aim of this study was to estimate the effect of Tan on the proliferation of cultured vascular smooth muscle cells (VSMCs) induced by fatal bovine serum (FBS). It was shown that various concentrations of Tan inhibited the VSMCs proliferation in a dose-dependent manner. Tan significantly blocked VSMCs cell cycle in G(0)/G(1) phase. The anti-proliferative effect of Tan was associated with the inhibition of the extracellular signal-regulated kinase1/2 (ERK1/2). On the other hand, the decrement of Tan on the cyclin D1 protein may be related to the high expression of p21(waf/cip1). The data suggest that the anti-proliferative effect of Tan on VSMCs proliferation was associated with ERK1/2 signaling pathway.
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Expression of mutationally activated RAS is a feature common to the vast majority of human pancreatic adenocarcinomas. RAS elicits its effects through numerous signaling pathways including the RAF-->mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase [MEK]-->ERK MAP kinase pathway. To assess the role of this pathway in regulating cell proliferation, we tested the effects of pharmacologic inhibition of MEK on human pancreatic cancer cell lines. In eight cell lines tested, MEK inhibition led to a cessation of cell proliferation accompanied by G0-G1 cell cycle arrest. Concomitant with cell cycle arrest, we observed induced expression of p27Kip1, inhibition of cyclin/cyclin-dependent kinase 2 (cdk2) activity, accumulation of hypophosphorylated pRb, and inhibition of E2F activity. Using both antisense and RNA interference techniques, we assessed the role of p27Kip1 in the observed effects of MEK inhibition on pancreatic cancer cell proliferation. Inhibition of p27Kip1 expression in Mia PaCa-2 cells restored the activity of cyclin/cdk2, phosphorylation of pRb, and E2F activity and partially relieved the effects of U0126 on pancreatic cancer cell cycle arrest. Consistent with the effects of p27Kip1 on cyclin/cdk2 activity, inhibition of CDK2 expression by RNA interference also led to G0-G1 cell cycle arrest. These data suggest that the expression of p27Kip1 is downstream of the RAF-->MEK-->ERK pathway and that the regulated expression of this protein plays an important role in promoting the proliferation of pancreatic cancer cells. Moreover, these data suggest that pharmacologic inhibition of the RAF-->MEK-->ERK signaling pathway alone might tend to have a cytostatic, as opposed to a cytotoxic, effect on pancreatic cancer cells.
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The mitogen-activated protein kinase (MAPK) family of kinases connects extracellular stimuli with diverse cellular responses ranging from activation or suppression of gene expression to the regulation of cell mortality, growth, and differentiation. The MAPK family has been studied extensively; however, the role of these kinases in cell growth and cell-cycle control has become increasingly complex. Patterns have begun to emerge from these studies that show the functions of MAPK subfamilies at different stages of the cell cycle. Their patterns of subcellular localization and movement during the cell cycle are subfamily-specific and have raised many questions about possible cell-cycle functions that have yet to be demonstrated. This article will compare and contrast our current understanding of the functions and localization patterns of the MAPK subfamilies (ERK, BMK, p38, and JNK) in cell-cycle control.
Article
The cell cycle represents a series of tightly integrated events that allow the cell to grow and proliferate. Critical parts of the cell cycle machinery are the cyclin-dependent kinases (CDKs), which, when activated, provide a means for the cell to move from one phase of the cell cycle to the next. The CDKs are regulated positively by cyclins and regulated negatively by naturally occurring CDK inhibitors (CDKIs). Cancer represents a dysregulation of the cell cycle such that cells that overexpress cyclins or do not express the CDKIs continue to undergo unregulated cell growth. The cell cycle also serves to protect the cell from DNA damage. Thus, cell cycle arrest, in fact, represents a survival mechanism that provides the tumor cell the opportunity to repair its own damaged DNA. Thus, abrogation of cell cycle checkpoints, before DNA repair is complete, can activate the apoptotic cascade, leading to cell death. Now in clinical trials are a series of targeted agents that directly inhibit the CDKs, inhibit unrestricted cell growth, and induce growth arrest. Recent attention has also focused on these drugs as inhibitors of transcription. In addition, there are now agents that abrogate the cell cycle checkpoints at critical time points that make the tumor cell susceptible to apoptosis. An understanding of the cell cycle is critical to understanding how best to clinically develop these agents, both as single agents and in combination with chemotherapy.
Article
Mu (Raphanus sativus, Korean White Radish) crude extract (Mu-CE) has been studied for its anti-proliferative activity on mouse aortic smooth muscle cells. The abnormal growth of vascular smooth muscle cells (VSMC) is a prominent feature of vascular disease, including atherosclerosis, restenosis after angioplasty. We examined the mechanisms of the action of Mu-CE on VSMC proliferation. The viability of VSMC decreased to 35% at 24 h of treatment with Mu-CE. Treatment of Mu-CE showed potent inhibitory effects on the DNA synthesis of cultured VSMC. In addition, Mu-CE induced apoptosis using cell death ELISA assay. These inhibitory effects were associated with G1 cell cycle arrest. Treatment of Mu-CE, which induced a cell-cycle arrest in G1-phase, induced down-regulation of cyclins and CDKs and up-regulation of the CDK inhibitor p21 expression, whereas up-regulation of p27 by Mu-CE was not observed. Then, total isothiocyanates (ITC) including four different 4-(Methylthio)-3-butenyl isothiocyanate (MTBITC), allyl isothiocayanate (AITC), benzyl isothiocyanate (BITC), and phenethyl isothiocyanate (PEITC) was isolated from n-hexane extracts of Mu. When the VSMC were treated with ITC, the cell viability was significantly decreased. These findings indicate the efficacy of Mu-CE in inhibiting cell proliferation, G1- to S-phase cell-cycle progress on VSMC.
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