Triiodothyronine Attenuates Prostate Cancer Progression Mediated by β-Adrenergic Stimulation

Abstract Prostate cancer cells are responsive to adrenergic and thyroid stimuli. It is well established that β-adrenergic activation (protein kinase A [PKA]/cAMP response element binding protein [CREB]) promotes cancer progression, but the role of thyroid hormones is poorly understood. We analyzed the effects of β-adrenergic stimulation (isoproterenol [ISO]) and/or thyroid hormone on neuroendocrine (NE) differentiation and cell invasion, using in vivo (LNCaP tumor) and in vitro models (LNCaP and DU145 human cells). Nude mice were inoculated with LNCaP cells and were treated for 6 wks with ISO (200 µg/d), triiodothyronine (T3, 2.5 µg/d) or both. ISO alone reduced tumor growth but increased tumor expression of cAMP response element (CRE)-dependent genes (real-time polymerase chain reaction, chromogranin A, neuron-specific enolase, survivin, vascular endothelial growth factor [VEGF], urokinase plasmin activator [uPA] and metalloproteinase-9 [MMP-9]) and some proteins related to NE differentiation and/or invasiveness (synaptophysin, VEGF, pCREB). T3 reduced tumor growth and prevented the overexpression of ISO-stimulated factors through a pCREB-independent mechanism. In low invasive LNCaP cells, 50 µmol/L ISO or 100 nmol/L thyroxine (T4) induced the acquisition of NE-like morphology (phase-contrast microscopy), increased VEGF secretion (ELISA) and invasive capacity (Transwell assay), but no synergistic effects were observed after the coadministration of ISO + T4. In contrast, 10 nmol/L T3 alone had no effect, but it prevented the NE-like morphology and invasiveness stimulated by ISO. None of these treatments had any effect on highly invasive DU145 cells. In summary, this study showed that ISO and T4 increase cancer progression, and T3 attenuates ISO-stimulated progression. Further studies are required to determine if changes in the ratio of T4/T3 could be relevant for prostate cancer progression

Cortisol modulates Ca2+ signaling and acrosome reaction in human sperm

Background: Stress and elevated cortisol levels have negative effects on fertility, although there is controversy about the effect of cortisol on human sperm. One study reported that hydrocortisone (HC), the synthetic form of cortisol, does not activate CatSper channel but is able to inhibit its activation by progesterone (Pg). However, subsequent reports showed that HC has an agonist effect on CatSper, producing intracellular Ca2+ ([Ca2+]i) increases. These studies were performed using only electrophysiological techniques and fluorometric measurements of Ca2+. Therefore, it is important to evaluate the effects of different HC concentrations on human sperm physiology using other approaches and techniques. Objective: To analyze the effects of different HC concentrations on human sperm physiology and to evaluate the association of perceived stress, anxiety and depression with acrosome reaction (AR), and semen quality. Materials and methods: In capacitated human sperm, we tested the effects of HC on [Ca2+]i mobilization and AR. Furthermore, the perceived stress and symptoms of anxiety and depression were evaluated with standardized psychometric tests. Results: HC induces a low increase in [Ca2+]i compared to Pg response while, at higher concentrations, HC inhibits the Pg-induced Ca2+ response. Also, low concentrations of HC induce AR and when co-incubating it with Pg, the percentages of AR are decreased. Finally, the anxiety symptoms are negatively correlated with Pg induced AR and semen quality. Discussion: HC has an agonist effect on [Ca2+]i mobilization and AR. However, our data also suggest that HC may compete for the binding site of Pg. Additionally, the association between anxiety and decreased AR could be explained by high cortisol levels. Conclusion: Our data showed that HC interferes with the Pg action. Therefore, the negative correlation between anxiety symptoms and Pg-induced AR is due to the accompanying high cortisol levels of this condition and its competitive action with Pg.Fil: Sánchez González, Sheini Ruturi. Universidad Autonoma de Queretaro.; MéxicoFil: Mata Martínez, Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Torres Juárez, Jorge Arturo. Universidad Autonoma de Queretaro.; MéxicoFil: Arias, Rodolfo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: de Blas, Gerardo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Sánchez Tusie, Ana Alicia. Universidad Autonoma de Queretaro.; Méxic

Epac activation induces an extracellular Ca2+-independent Ca2+ wave that triggers acrosome reaction in human spermatozoa

Background: The signaling pathways of the intracellular second messengers cAMP and Ca2+ play a crucial role in numerous physiological processes in human spermatozoa. One such process is the acrosome reaction (AR), which is necessary for spermatozoa to traverse the egg envelope and to expose a fusogenic membrane allowing the egg–sperm fusion. Progesterone and zona pellucida elicit an intracellular Ca2+ increase that is needed for the AR in the mammalian spermatozoa. This increase is mediated by an initial Ca2+ influx but also by a release from intracellular Ca2+ stores. It is known that intracellular Ca2+ stores play a central role in the regulation of [Ca2+]i and in the generation of complex Ca2+ signals such as oscillations and waves. In the human spermatozoa, it has been proposed that the cAMP analog and specific agonist of Epac 8-(p-chlorophenylthio)-2'-O-methyladenosine-3’,5'-cyclic monophosphate (2'-O-Me-cAMP) elicits an intracellular Ca2+ release involved in the AR. Objective: To identify the molecular entities involved in the Ca2+ mobilization triggered by 2'-O-Me-cAMP in human spermatozoa. Materials and Methods: In capacitated human spermatozoa, we monitored Ca2+ dynamics and the occurrence of the AR in real time using Fluo 3-AM and FM4-64 in a Ca2+-free medium. Results: Epac activation by 2'-O-Me-cAMP induced a Ca2+ wave that started in the midpiece and propagated to the acrosome region. This Ca2+ response was sensitive to rotenone, CGP, xestospongin, NED-19, and thapsigargin, suggesting the participation of different ion transporters (mitochondrial complex I and Na+/Ca2+ exchanger, inositol 3-phosphate receptors, two-pore channels and internal store Ca2+-ATPases). Discussion: Our results suggest that Epac activation promotes a dynamic crosstalk between three different intracellular Ca2+ stores: the mitochondria, the redundant nuclear envelope, and the acrosome. Conclusion: The Ca2+ wave triggered by Epac activation is necessary to induce the AR and to enhance the flagellar beat.Fil: Mata Martínez, Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Sánchez Tusie, Ana Alicia. Universidad Autonoma de Queretaro.; MéxicoFil: Darszon, Alberto. Universidad Nacional Autónoma de México; MéxicoFil: Mayorga, Luis Segundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; ArgentinaFil: Treviño, Claudia L.. Universidad Nacional Autónoma de México; MéxicoFil: de Blas, Gerardo Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentin