Histology and histopathology Vol.23,nº10 (2008)
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- PublicationOpen AccessNucleolus, The ribosome factory(Murcia : F. Hernández, 2008) Cmarko, Dusan; Smigova, Jana; Minichova, Lucía; Popov, AlexeyThe nucleolus is a nuclear compartment and represents the most obvious and clearly differentiated nuclear structure seen in the microscope. Within nucleoli most events of ribosome biogenesis, such as ribosomal RNA synthesis, processing, and ribosome subunit assembly, take place. Several lines of evidence now show that the nucleolus has also numerous nonribosomal functions. This review is focused on the recent progress in our knowledge of how to correlate the known biochemical processes taking place in the nucleolus with nucleolar structures observed in the microscope. We still lack detailed enough information to understand fully the organization and regulation of the processes taking place in the nucleolar sub-structures. However, the present power of microscopy techniques should allow for an in situ description of the organization of nucleolar processes at the molecular level in the years to come.
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- PublicationOpen AccessAkt pathway as a target for therapeutic intervention in HNSCC(Murcia : F. Hernández, 2008) Moral, Marta; Paramio, Jesús M.Head and neck squamous cell carcinoma (HNSCC) is the sixth most common form of cancer worldwide. One frequent alteration found in this type of cancer is overactivation of the PI3K/PTEN/mTOR pathway, of which protein kinase B (PKB)/Akt is a central key element, controlling important cellular processes such as metabolism, cell size, proliferation and apoptosis, ultimately regulating cell growth and survival. Thus, drugs that target Akt directly or elements of the pathway are plausible candidates for cancer treatment. Accordingly, numerous clinical trials in various phases are being performed for these drugs. In this review, we discuss the tumorigenic capacity of Akt and focus on its role in HNSCC, paying special attention to the current efforts in treating this cancer in a more specific, Akttargeted way, based on its primordial role in this type of cancer.
- PublicationOpen AccessInvolvement of pro-apoptotic and anti-apoptotic factors in the early development of the human pituitary gland(Murcia : F. Hernández, 2008) Saraga-Babic, Mirna; Bazina, Mirna; Vukojevic, Katarina; Bocina, Ivana; Stefanovic, VedranThe spatial and temporal pattern of appearance of pro-apoptotic caspase-3 and p53 proteins, and anti-apoptotic bcl-2 protein was investigated in the developing pituitary gland of 6 human embryos 5-8- weeks old, using morphological and immunohistochemical techniques. Their dynamic appearance was analyzed in the Rathke's pouch (future adenohypophysis), mesenchyme, and in the developing neurohypophysis. In the 5th and 6th week, caspase-3 positive cells appeared in the Rathke's pouch (5%) and stalk (11%), in the mesenchyme, but not in the neurohypophysis. In the 6th and 7th week, apoptotic cells were more numerous in the caudal part of the Rathke's pouch due to its separation from the oral epithelium. Pro-apoptotic p53 protein was detected in all parts of the pituitary gland throughout the investigated period. Nuclear condensations characterized cells positive to caspase-3 and p53 proteins. Apoptotic cells displayed condensations of nuclear chromatin on an ultrastructural level as well. While caspase-3 dependent pathway of cell death participated in morphogenesis of the adenohypophysis and associated connective tissue, p53-mediated apoptosis most likely participates in morphogenesis of all parts of the gland, including neurohypophysis. The anti-apoptotic bcl-2 protein was also detected in all parts of the developing gland. With advancing development, the positivity to bcl-2 protein increased in the cells of the adenohypophysis, while it decreased in the neurohypophysis. Bcl-2 protein probably prevented cell death in all parts of the gland and enhanced cell differentiation. The described pattern of appearance of the investigated pro-apoptotic and antiapoptotic factors might be important for normal morphogenesis and function of the pituitary gland.
- PublicationOpen AccessReg I protein in healthy and seminoma human testis(Murcia : F. Hernández, 2008) Mauro, V.; Carette, D.; Chevallier, D.; Michiels, J.F.; Segretain, D.; Pointis, G.; Sénégas-Balas, F.Regenerating gene (Reg), encodes a secretory protein with growth and differentiation stimulating effects mostly in digestive tissues. Overexpression of Reg proteins and specifically of Reg I, one member of the Reg family, is associated with several human diseases and cancers. In the present study we analyzed the expression of Reg I in normal rodent and human testes where germ cells normally proliferate and differentiate into spermatozoa, and in seminoma testis, the most common cancer of young men. Western blot analyses demonstrated the presence of a specific band at 19 kDa in human and rodent testis extracts. Immunofluorescence and deconvolution microscopy demonstrated that Reg I was present within the seminiferous tubules in both Sertoli and germ cells. By using a Sertoli cell line we demonstrated that Reg I was localized at the plasma membrane even in the absence of contact between neighboring cells and appeared before the tight junction associated protein ZO-1 was revealed at this location. Reg I was strongly expressed in human seminoma testis tissue and in a human tumor germ cell line where the immunoreactive signal was mainly detected at the plasma membrane level. These data showing for the first time the weak presence of Reg I in the normal testis and its strong expression in the testis cancer suggest a potential role of Reg I in normal and neoplastic germ cell proliferation.
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