| 2. |
- Hu, Zhiwei, et al.
(författare)
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Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis
- 2015
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP): Policy B - Oxford Open Option B. - 0143-3334 .- 1460-2180. ; 36, s. S184-S202
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Forskningsöversikt (refereegranskat)abstract
- Angiogenesis is an important hallmark of cancer. We reviewed the various pathways controlling angiogenesis, summarized the possible role of specific environmental chemicals disrupting these pathways and listed assays for assessing the effects of low-dose exposures to chemicals in promoting tumor angiogenesis.One of the important hallmarks of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.
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| 3. |
- Bottone, Maria Grazia, et al.
(författare)
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Multiple effects of paclitaxel are modulated by a high c-myc amplification level.
- 2003
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Ingår i: Experimental cell research. - 0014-4827. ; 290:1, s. 49-59
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Tidskriftsartikel (refereegranskat)abstract
- Paclitaxel affects microtubule stability by binding to beta-tubulin, thus leading to cell accumulation in the G(2)/M phase, polyploidization, and apoptosis. Because both cell proliferation and apoptosis could be somehow regulated by the protooncogene c-myc, in this work we have investigated whether the c-myc amplification level could modulate the multiple effects of paclitaxel. To this aim, paclitaxel was administered to SW613-12A1 and -B3 human colon carcinoma cell lines (which are characterized by a high and low c-myc endogenous amplification level, respectively), and to the B3mycC5 cell line, with an enforced exogenous expression of c-myc copies. In this experimental system, we previously demonstrated that a high endogenous/exogenous level of amplification of c-myc enhances serum deprivation- and DNA damage-induced apoptosis. Accordingly, the present results indicate that a high c-myc amplification level potentiates paclitaxel cytotoxicity, confers a multinucleated phenotype, and promotes apoptosis to a great extent, thus suggesting that c-myc expression level is relevant in modulating the cellular responses to paclitaxel. We have recently shown in HeLa cells that the phosphorylated form of c-Myc accumulates in the nucleus, as distinct nucleolar and extranucleolar spots; here, we demonstrated that, after the treatment with paclitaxel, phosphorylated c-Myc undergoes redistribution, becoming diffused in the nucleoplasm.
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