Pathological characteristic of adamantinomatous craniopharyngioma (a–d). (b–d) are higher power view of the boxes 1–3 in (a), respectively. Tumor tongues surrounded by fibrosis showing “stellate reticulum,” “wet” keratin, intralobular cystic degeneration, as well as cellular whorls
Adult stem cells maintain some markers expressed by embryonic stem cells and express other specific markers depending on the organ where they reside. Recently, stem/progenitor cells in the humans have been characterized as expressing GFAP and stem cell markers such as CD133 and CD44. Our results indicate tumor stem cell-like characteristics of CD133- and CD44-accumulating cell clusters in ACP, which may represent a tumor stem cell niche and might contribute to tumor recurrence. The potential impact of these special cell groups regarding future CP management, including postoperative follow-up and additional treatment, remains to be explored (Fig. 9.3).
Compared with malignant tumors, craniopharyngioma cells have a slow proliferation and a decrease in cell activity and phenotypic changes after multiple passages of primary cells, making them no longer suitable for in vivo and in vitro studies. Therefore, there is a need for a cell line that does not change traits during the experimental period and has a single characteristic. Therefore, the author’s research center used the virus to prepare different types of immortalized craniopharyngioma cell lines. These tumor cells are the most stable and suitable for long-term experiments. As a powerful tool, it is a great advantage in benign tumor research with immortalized ACP cell line (Fig 9.4).
9.3 Neurogenesis in the Hypothalamus
Over the past few decades, with the development of progressively better tools for labeling and tracking newborn neurons, studies in multiple species have clarified that neurogenesis occurs in several brain regions in adult mammals. Initially, scientists confirmed that two main regions of active neurogenesis in the adult rodent brain occur in the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus in the hippocampus. With the development of neurogenesis research, a steady accumulation of evidence has suggested that the adult mammalian hypothalamus is not only a multifunctional center in the brain but also the third neurogenic niche in adult mammalians.
According to the recent research on adult hypothalamus neurogenesis, the third ventricle (3V), paraventricular zone, periventricular zone, and the median eminence (ME) can be the plausible candidates of the hypothalamic neurogenesis niche (Figs. 9.5 and 9.6). The ventricular zone of the mediobasal hypothalamus is largely composed of specialized radial glial-like cells called tanycytes, which line all but the most ventrally located portion of the 3V wall in this region. In contrast to the multiciliated ependymal cells that line the ventricles in most of the brain, tanycytes extend only one or two apical cilia into the ventricle and, depending on their location, project a long extended basal process either into the hypothalamic parenchyma or toward the pial surface of the hypothalamus. These radial processes are highly reminiscent of those shown by neural progenitors in the embryonic brain, which also serve as a substrate for radial migration of newly postmitotic neurons. Tanycytes express many genes that are also selectively expressed in embryonic hypothalamic progenitor cells and/or are expressed in neural stem cells of the SVZ and SGZ. These include transcription factors such as Rax, Lhx2, Sox2, and Sox9; intermediate filament proteins such as Nestin, vimentin (Fig. 9.7), and GFAP; growth factors such as Fgf10 and Fgf18; and Notch pathway components such as Notch1, Notch2, and Hes5.