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Establishment and Characterization of Cancer Cell Lines for Companion Diagnostics
Published in Il-Jin Kim, Companion Diagnostics (CDx) in Precision Medicine, 2019
The problems faced by tumor culture are from (i) the autonomy of tumor populations that may allow the growth of tumor cells under conditions that normal cells do not proliferate, (ii) the size of the proliferating pool of the tumor being greater than that of most normal tissues, and (iii) the ability of tumor cells to produce a more persistent immortalized cell line more frequently than normal cells (Whitescarver, 1974). This last characteristic, unlike anything else, has made possible an extensive study of the tumor cell population, even in the normal differentiation process, despite the uncertainty of its relationship to tumor cells (Freshney, 2011).
Factors Influencing Growth and Differentiation of Normal and Transformed Human Mammary Epithelial Cells in Culture
Published in George E. Milo, Bruce C. Casto, Charles F. Shuler, Transformation of Human Epithelial Cells: Molecular and Oncogenetic Mechanisms, 2017
Martha R. Stampfer, Paul Yaswen
The model system for human mammary carcinogenesis which we have developed likewise has its values and limitations. We have available cells from one individual which display a progression of changes which correlate with changes observed during carcinogenic progression — extended life-span, immortality, growth factor independence, and tumorigenicity. The immortal cell populations retain most of the growth factor requirements of the normal HMEC, display a more luminal phenotype than the normal HMEC grown in MCDB 170, and show minimal genetic instability. While any immortalized cell line cannot be considered to represent normal cells, lines of indefinite life-span are in many instances more convenient to use than finite life-span cells. The retention by 184A1 and 184B5 of many normal characteristics makes them useful substrates for some areas of experimentation in normal cell physiology. On the other hand, the fact that they have acquired some aberrant properties relative to normal HMEC, especially their indefinite lifespan, makes them useful substrates for determining the potential capacity of additional factors (e.g., chemical and physical carcinogens, oncogenic viruses, and transfected genes) to induce malignant transformation.
Recent advances in cellular models for discovering prion disease therapeutics
Published in Expert Opinion on Drug Discovery, 2022
Lea Nikolić, Chiara Ferracin, Giuseppe Legname
While the ideal immortalized cell line would be the one stably propagating human prions in human cells, experiments with human prions can potentially lead to devastating consequences. Prions are unlikely to be detected on contaminated laboratory equipment and cannot be inactivated by standard decontamination procedures [46]. To assess prion propagation in a human genetic background, while circumventing the human-safety issue, Avar et al. constructed the human neuroblastoma cell line (SH-SY5Y) lacking the human PRNP gene (SHSY5YΔPRNP) and expressing the ovine PRNP VRQ allele instead [47,48]. Ovinized human SH-SY5Y cells were shown to be permissive to infection with sheep-derived murine prions, shown by WB analysis of PrPres. The authors also reported pathological vacuolation in prion-infected cells and the absence of such phenotype in the normal brain homogenate (NBH)-treated cells. Therefore, apart from its value in pharmaceutical studies, broadening the spectrum of infectable, genetically engineered cell lines can aid in deciphering cellular factors contributing to susceptibility of different cells to different prion strains. The full potential of the genetically engineered systems can also be exploited in the studies of genetic mutations (or polymorphisms) of the species-associated PrP and its influence on the species barrier.
The health effects of short fiber chrysotile and amphibole asbestos
Published in Critical Reviews in Toxicology, 2022
In vitro cell culture studies of fibers are accessible, and these testing methods are valuable to elucidate possible mechanisms involved in pathogenesis. In vitro, cellular systems are most often static systems and not sensitive to differences in fiber solubility. There are usually performed with a single layer of a specific immortalized cell line. An immortalized cell line is a population of cells from a multicellular organism that would normally not proliferate indefinitely but, due to mutation, have evaded normal cellular senescence and instead can keep undergoing division. Immortalized cells are primary cells whose telomeres and/or tumor suppressor genes have been altered to facilitate continued cell division. The cells can therefore be grown for prolonged periods in vitro. This is in contrast to in-vivo inhalation studies where the fibers are exposed to the dynamic behavior of the respiratory system with systematic interaction and signaling between multiple cell types. In addition, the effect of lung surfactants and the fluid flows of the lung are not present.
Research in a time of enteroids and organoids: how the human gut model has transformed the study of enteric bacterial pathogens
Published in Gut Microbes, 2020
Sridevi Ranganathan, Emily M. Smith, Jennifer D. Foulke-Abel, Eileen M. Barry
The bacterial pathogenesis studies discussed in this review, in addition to efforts using viral pathogens and parasites, demonstrate the functionality of enteroid and organoid models for infectious disease research. Many infection responses that were previously identified in cell lines or animals have been confirmed in enteroids/organoids, but some direct comparisons have revealed new model-specific phenotypes. This has been illustrated in the enhanced receptor expression yet diminished response to C. difficile toxins in enteroids compared to T84 and HT-29 cells,41 and the level and polarized secretion pattern of cGMP upon ETEC infection in enteroids compared to T84 and Caco-2 cells.30 The utility of enteroids/organoids is further justified in the novel mechanistic findings such as those related to intestinal segment tropism (Shigella, EAEC), histo-blood group antigens (ETEC), cell surface glycosylations (cholera toxin), a complex mucus layer (Shigella, EAEC, EHEC, C. difficile), and the ability to compare fetal and adult human tissue states (NEC). Each of these features is not directly mimicked in animal or immortalized cell line experiments.