Significance
The formation of new blood vessels (neoangiogenesis) accompanies tissue regeneration and healing, but is also crucial for tumor growth, hence understanding how capillaries are stimulated to grow in response to local cues is essential for the much sought-after aim of controlling this process. We have elucidated a Ca
2+
signaling pathway involving NAADP, TPCs, and lysosomal Ca
2+
release activated in vascular endothelial cells by VEGF, the main angiogenic growth factor, and we show that the angiogenic response can be abolished, in cultured cells and in vivo, by inhibiting components of this signaling cascade. The specificity of this pathway in terms of VEGF receptor subtype, intracellular messengers, target channels and Ca
2+
storage organelles, offers new targets for novel antiangiogenic therapeutic strategies.
A new technique involving a brief hypotonic treatment was developed for obtaining pure rat Sertoli cell cultures. This method forthe selective removal of the germ cells present in Sertoli cell enriched cultures (SCEC) is based on the differential response of the two cell types to changes in osmolarity. It was found that the optimal conditions for germ cell detachment without Sertoli cell impairment consist of incubation for 2.5 minutes at 20 C in 20 mM TRIS-HCl. When compared with SCEC, the Sertolicell-onlycultures (SCOC) thus obtained retain unaltered morphologic features and responsiveness to FSH stimulation (morphologic modifications and 17 -estradiol secretion). The availability of pure Sertoli cell cultures (ie, free of contaminating germ cells) provides an advantage in the study of their metabolic activity. Moreover, with this technique it is feasible to compare Sertoli cell function in association with germ cells to function in the absence of germ cells
Toll-like receptors (TLRs) are known to play a key role in the innate immune system particularly in inflammatory response against invading pathogens. Recent reports strongly indicate that they play important roles in cancer cells. Prostate cancer represents one of the most common cancer for which no cure is available once metastatic and androgen refractory. Since TLR3 has been recently suggested as a possible therapeutic target in some cancer cell lines, we studied TLR3 expression and functionality in two human prostate cancer cell lines, LNCaP and PC3. We report that both cell lines express TLR3 and that the TLR3 agonist poly (I:C) activates mitogen-activated protein kinases and induces inhibition of proliferation as well as caspase-dependent apoptosis. By using pharmacological and genetic approaches, we demonstrate the involvement of TLR3 in poly (I:C)-induced effects. We also show that a novel interferon-independent pathway involving protein kinase C (PKC)-alpha activation, upstream of p38 and c-jun N-terminal kinase, is responsible for poly (I:C) pro-apoptotic effects on LNCaP cells. To our knowledge, this is the first report describing a role of PKC-alpha in poly (I:C)-mediated apoptosis. The comprehension of the mechanisms underlying TLR3-mediated apoptosis can contribute tools to develop new agonists useful for the treatment of prostate cancer.
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