Biomedical subjects

Paolo Chieffi

Publications and source records attributed to Paolo Chieffi.

22 records · Page 2Linked to original sources

PubMed2002

HMGA1 and HMGA2 protein expression in mouse spermatogenesis.

The high-mobility group A (HMGA) nonhistone chromosomal proteins HMGA1 and HMGA2 play a role in determining chromatin structure and in regulating the transcription of several genes. High levels of these proteins are characteristic of rapidly dividing cells in embryonic tissue and in tumors. The aim of this study was to determine the role of HMGA1 and HMGA2 throughout mouse spermatogenesis. Northern blot analysis and immunocytochemistry showed HMGA1 and HMGA2 expression during the progression from spermatocyte to spermatid. Interestingly, Western blot analysis with antibodies against the HMGA1 gene product revealed only the HMG1c isoform (27 kDa) in the testis; HMGA1a and HMGA1b were undetectable. These three isoforms are encoded by the HMGA1 gene through alternative splicing. Finally, few spermatids and complete absence of spermatozoa were observed in the testes of HMGA2-null mice, which suggests that the HMGA2 gene plays a critical role in male fertility.

Animals↗

PubMed2002

Proline-rich tyrosine kinase 2 regulates proliferation and differentiation of prostate cells.

Proline-rich tyrosine kinase 2 (Pyk2) expression in prostate epithelium inversely correlated with degree of malignancy of prostate cancers, thus the role of Pyk2 in the regulation of prostate cells proliferation and differentiation was investigate in PC3 cells. Pyk2 can be activated by canonic stimuli such as tumor necrosis factoralpha and lysophosphatidic acid (LPA) in PC3 cells, in addition, LPA stimulated Pyk2 phosphorylation also induced extracellular signal-regulated kinase 1 and 2 activation in these cells. Proliferation of PC3 cell clones (PC3-PKM) expressing a dominant negative kinase-defective Pyk2 mutant is consistently decreased in respect to that of wild type PC3 cells. In addition, PC3-PKM clones underwent total block cell proliferation upon treatment with dibutyryl cAMP. Finally, in the presence of sustained levels of intracellular cAMP, PC3-PKM cells, but not wild type PC3 cells, acquired a neuron-like morphology. Taken together our results suggest that Pyk2 plays a role in the regulation of prostate cell proliferation and, more interestingly, its expression may represents a sensitive marker of prostate state of differentiation.

Bucladesine↗

PubMed2002

17 beta-estradiol induces spermatogonial proliferation through mitogen-activated protein kinase (extracellular signal-regulated kinase 1/2) activity in the lizard (Podarcis s. sicula).

There are always more evidences indicating that 17beta-estradiol (E(2)) is necessary for normal male fertility. We have used a nonmammalian vertebrate model (the lizard Podarcis s. sicula) to investigate the regulation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) activity in the testis during the annual sexual cycle and to study whether E(2) exerts a role in the spermatogenesis through ERK1/2 activity. Immunocytochemistry analysis shows that ERK1/2 proteins are present in the nucleus of the spermatogonia (SPG), and in primary (I) spermatocytes (SPC). The annual E(2) profile shows a progressive increase during the active spermatogenesis (from April to June) and a peak in the month of August (spermatogonial mitosis). In parallel, ERK1/2 (molecular weight 44 and 42 kDa, respectively) are highly phosphorylated during the period of active spermatogenesis and in post-refractory period (August) compared with the winter stasis (from November to March). Present results demonstrate that E(2) treatment induces spermatogonial proliferation, possibly via the activation of ERK1/2, and this effect is counteracted by the antiestrogen ICI 182-780.

Animals↗

PubMed2002

EPN: a novel epithelial cell line derived from human prostate tissue.

This work reports the isolation and characterization of a line of human, nontransformed and differentiated prostate epithelial cells (EPN) in continuous culture. Primary cultures of epithelial prostate cells were set up using normal tissue isolated from a prostate sample collected after radical prostatectomy for cancer. After 70 passages, EPN cells did not undergo "Hayflike crisis" and were free of fibroblast contamination and were thus subcloned and characterized. EPN cells in culture, as prostate epithelial cells in vivo, express high-molecular weight cytokeratin and Pyk2, whereas they do not express desmin. EPN cells are nontransformed because they do not form colonies in semisolid medium and do not form tumors once injected into nude mice. EPN cells express the functional androgen receptor, which can mediate the mitogenic activity of testosterone. Finally, clonal production of the prostate-specific antigen could be detected in EPN cells. The availability of a line of epithelial nontransformed prostate cell in culture will be useful in investigating the complex process regulating normal prostate physiology as well as the development and progression of prostate tumors.

3T3 Cells↗