Spiroquinazolinones as novel, potent, and selective PDE7 inhibitors. Part 1

The synthesis and SAR studies of spiroquinazolinones as novel PDE7 inhibitors are discussed. The best compounds from the series displayed nanomolar inhibitory affinity and were selective versus other PDE isoenzymes.     

Galphaq-coupled receptor internalization specifically induced by Galphaq signaling. Regulation by EBP50

In the present report, we investigated the effect of ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) expression on the agonist-induced internalization of the thromboxane A(2) beta receptor (TPbeta receptor). Interestingly, we found that EBP50 almost completely blocked TPbeta receptor internalization, which could not be reversed by overexpression of G protein-coupled receptor (GPCR) kinases and arrestins. Because we recently demonstrated that EBP50 can bind to and inhibit Galpha(q), we next studied whether Galpha(q) signaling could induce TPbeta receptor internalization, addressing the long standing question about the relationship between GPCR signaling and their internalization. Expression of a constitutively active Galpha(q) mutant (Galpha(q)-R183C) resulted in a robust internalization of the TPbeta receptor, which was unaffected by expression of dominant negative mutants of arrestin-2 and -3, but inhibited by expression of EBP50 or dynamin-K44A, a dominant negative mutant of dynamin. Phospholipase Cbeta and protein kinase C did not appear to significantly contribute to internalization of the TPbeta receptor, suggesting that Galpha(q) induces receptor internalization through a phospholipase Cbeta- and protein kinase C-independent pathway. Surprisingly, there appears to be specificity in Galpha protein-mediated GPCR internalization. Galpha(q)-R183C also induced the internalization of CXCR4 (Galpha(q)-coupled), whereas it failed to do so for the beta(2)-adrenergic receptor (Galpha(s)-coupled). Moreover, Galpha(s)-R201C, a constitutively active form of Galpha(s), had no effect on internalization of the TPbeta, CXCR4, and beta(2)-adrenergic receptors. Thus, we showed that Galpha protein signaling can lead to internalization of GPCRs, with specificity in both the Galpha proteins and GPCRs that are involved. Furthermore, a new function has been described for EBP50 in its capacity to inhibit receptor endocytosis.     

Lysosomal and proteasomal degradation play distinct roles in the life cycle of Cx43 in gap junctional intercellular communication-deficient and -competent breast tumor cells

The present study was designed to determine the specific roles played by lysosomes and proteasomes in the degradation of Cx43 in both gap junctional intercellular communication-deficient MDA-MB-231 and -competent BICR-M1Rk cells. In MDA-MB-231 cells, immunolocalization and brefeldin A protein transport blocking studies revealed that there was a propensity for newly synthesized Cx43 to be transported to lysosomes. On the other hand, light and electron microscopic analysis of BICR-M1Rk cells showed that Cx43 gap junctions were prevalent with a subpopulation of intracellular Cx43 localized to lysosomes. In both cell types, Western blots revealed a notable increase in total cellular Cx43 in response to lysosome inhibitors. Interestingly, lactacystin inhibition of proteosomal degradation in MDA-MB-231 cells resulted in a marked increase in phosphorylated Cx43 at the expense of non-phosphorylated Cx43, and this change corresponded with an increase in "oversized" gap junction plaques. In BICR-M1Rk cells, lactacystin treatment partially prevented the BFA-induced loss of gap junctions. Together, our data suggests that lysosomes play a key role in not only degrading internalized gap junction in BICR-M1Rk cells but also in degrading Cx43 delivered from early secretory compartments to lysosomes in MDA-MB-231 cells. Overall proteasomal degradation regulates the stability of phosphorylated Cx43 and appears to promote the internalization of Cx43 from the cell surface.     

Benign paratesticular fibrous pseudotumor with malignant clinical features

Paratesticular tumors are rare intrascrotal masses that grow mainly in structures containing connective tissue around the testis, epididymis, or spermatic cord. We report here on a case of a 55-year-old man with a mass in the hemiscrotum that was found to be a paratesticular fibrous pseudotumor in the orchiectomy specimen pathologic examination. From this case report and literature review, a diagnostic and therapeutic strategy is demonstrated for the management of this uncommon lesion.     

Concomitant sertoli and leydig cell tumor of the testis: a case report

A rare intratubular gonadal stromal tumor was present in the testis of a 45-year-old man who was admitted to our hospital with the chief complaint of gradual enlargement of the left testis. Tumoral markers were negative and no extension was observed. The tumor comprised an intratubular mixture of two types of tumor cells with intercellular junctions: the predominant tumor cells were consistent with a Sertoli cell origin and cells comprising the minor population consistent with a Leydig cell origin. The patient is disease free after 6-month follow-up. The case is considered to be a testicular mixed tubular Sertoli-Leydig cell tumor. It highlights a rare type of primary tumor of the testis that features a good prognosis.     

Toxin-based in-vitro selection and its potential application to date palm for resistance to the bayoud Fusarium wilt

Date palm (Phoenix dactylifera L.) is qualified as a 'tree' of great ecological and socio-economical importance in desert oases. Unfortunately, it is being decimated, especially in Morocco and Algeria, by a fusariosis wilt called bayoud and caused by Fusarium oxysporum f. sp. albedinis (Fao). Controlling this disease requires the implementation of an integrated management program. Breeding for resistance is one of the most promising component strategies of this program. Few naturally resistant cultivars with a mediocre fruit quality (dates) are known. Conventional and non-conventional methods are under development and have to use the simplest and easiest methods to screen for resistant individuals. The use of pathogen toxins as selective agents at the tissue culture step might be a source of variability that can lead to the selection of individuals with suitable levels of resistance to the toxin and/or to the pathogen among the genetic material available. Foa produces toxins such as fusaric, succinic, 3-phenyl lactic acids and their derivatives, marasmins and peptidic toxins. These toxins can be used bulked or separately as selective agents. The aim of this contribution was to give a brief overview on toxins and their use as a mean to select resistant lines and to initiate a discussion about the potential use of this approach for the date palm-Foa pathosystem. This review does not pretend to be comprehensive or exhaustive and was prepared mainly to highlight the potential use of Foa toxins for selecting date palm individuals with a suitable resistance level to bayoud using toxin-based selective media.