Endothelin A receptor drives invadopodia function and cell motility through the ß-arrestin/PDZ-RhoGEF pathway in ovarian carcinoma.

The endothelin-1 (ET-1)/ET A receptor (ETAR) signalling pathway is a well-established driver of epithelial ovarian cancer (EOC) progression. One key process promoted by ET-1 is tumor cell invasion, which requires the scaffolding functions of ß-arrestin-1 (ß-arr1) downstream of the receptor; however, the potential role of ET-1 in inducing invadopodia, which are crucial for cellular invasion and tumor metastasis, is completely unknown. We describe here that ET-1/ETAR, through ß-arr1, activates RhoA and RhoC GTPase and downstream ROCK (Rho-associated coiled coil-forming kinase) kinase activity, promoting actin-based dynamic remodelling and enhanced cell invasion. This is accomplished by the direct interaction of ß-arr1 with PDZ-RhoGEF (postsynaptic density protein 95/disc-large/zonula occludens-RhoGEF). Interestingly, ETAR-mediated invasive properties are related to the regulation of invadopodia, as evaluated by colocalization of actin with cortactin, as well as with TKS5 and MT1-MMP (membrane type 1-matrix metalloproteinase) with areas of matrix degradation, and activation of cofilin pathway, which is crucial for regulating invadopodia activity. Depletion of PDZ-RhoGEF, or ß-arr1, or RhoC, as well as the treatment with the dual ET-1 receptor antagonist macitentan, significantly impairs invadopodia function, MMP activity and invasion, demonstrating that ß-arr1/PDZ-RhoGEF interaction mediates ETAR-driven ROCK-LIMK-cofilin pathway through the control of RhoC activity. In vivo, macitentan is able to inhibit metastatic dissemination and cofilin phosphorylation. Collectively, our data unveil a noncanonical activation of the RhoC/ROCK pathway through the ß-arr1/PDZ-RhoGEF complex as a regulator of ETAR-induced motility and metastasis, establishing ET-1 axis as a novel regulator of invadopodia protrusions through the RhoC/ROCK/LIMK/cofilin pathway during the initial steps of EOC invasion.

ß-arrestin-1 is a nuclear transcriptional regulator of endothelin-1-induced ß-catenin signaling.

Despite the fundamental pathophysiological importance of ß-catenin in tumor progression, the mechanism underlying its final transcriptional output has been partially elucidated. Here, we report that ß-arrestin-1 (ß-arr1) is an epigenetic regulator of endothelin (ET)-1-induced ß-catenin signaling in epithelial ovarian cancer (EOC). In response to ET A receptor (ETAR) activation by ET-1, ß-arr1 increases its nuclear translocation and direct binding to ß-catenin. This in turn enhanced ß-catenin nuclear accumulation and transcriptional activity, which was prevented by expressing a mutant ß-arr1 incapable of nuclear distribution. ß-arr1-ß-catenin interaction controls ß-catenin target gene expressions, such as ET-1, Axin 2, Matrix metalloproteinase 2, and Cyclin D1, by promoting histone deacetylase 1 (HDAC1) dissociation and the recruitment of p300 acetyltransferase on these promoter genes, resulting in enhanced H3 and H4 histone acetylation, and gene transcription, required for cell migration, invasion and epithelial-to-mesenchymal transition. These effects are abrogated by ß-arr1 silencing or by mutant ß-arr1, as well as by ß-catenin or p300 silencing, confirming that nuclear ß-arr1 forms a functional complex capable of regulating epigenetic changes in ß-catenin-driven invasive behavior. In a murine orthotopic model of metastatic human EOC, silencing of ß-arr1 or mutant ß-arr1 expression, as well as ETAR blockade, inhibits metastasis. In human EOC tissues, ß-arr1-ß-catenin nuclear complexes are selectively enriched at ß-catenin target gene promoters, correlating with tumor grade, confirming a direct in vivo ß-arr1-ß-catenin association at specific set of genes involved in EOC progression. Collectively, our study provides insights into how a ß-arr1-mediated epigenetic mechanism controls ß-catenin activity, unraveling new components required for its nuclear function in promoting metastasis.

Cooperative study comparing three methods of performing sweat tests to diagnose cystic fibrosis.

Directors of cystic fibrosis centers in the United States have noted an increasing number of patients with histories of either false-positive or false-negative sweat tests. These inaccuracies were attributed to the use of rapid test methods which avoided actually weighing the sweat collected. These rapid tests have inherent difficulties which, theoretically at least, could lead to mistaken diagnoses. To evaluate methods of performing the sweat test, the National Cystic Fibrosis Foundation organized a combined study comparing the older Quantitative pilocarpine iontophoretic test (QPIT) method of performing the test with two newer and more rapid methods, the Orion skin electrode, and the Medtherm conductivity apparatus. Five cystic fibrosis centers participated in the study. Although two centers obtained considerably more accurate results with the Orion and the Medtherm than did the other three centers, the combined results of the study indicate that these procedures can be considered to be little more than screening tests.

Laboratory confirmation of the diagnosis of cystic fibrosis.

The recent commercial introduction of a method for detecting albumin in meconium makes screening for cystic fibrosis feasible for many hospitals. If the tests is adopted, confirmatory tests should be available. Quantitative analyses of sweat for sodium by flame photometry and for chloride by silver titration and ion-sleective electrodes are now used as confirmatory tests. We compare results of these confirmatory methods applied to presons with cystic fibrosis, respiratory disorders, or digestive disorders, and to control subjects.

Unusual complications of transvesical ureteral reimplantation.

Four of 8 cases that represent unusual and infrequent complications of the transvesicle Politano-Leadbetter ureteral reimplantation technique are reported. Approximately 90 per cent of ureteral reimplantations for vesicoureteral reflux may be done satisfactorily as a transvesical procedure but combining it with an extravesical approach of the ureter when necessary or indicated will serve to correct any conceivable congenital, acquired or iatrogenic lesion of the lower ureteral segment. The extravesical approach should be used if there is any difficulty in performing the procedure transvesically or if the patient has undergone previous attempts at antireflux operation. Obstructive complications may occur in either the early or late postoperative period. When discovered, surgical correction is usually indicated. We strongly advocate strict adherence to the surgical technique involved and meticulous postoperative followup of these patients.

Spontaneous rupture of the kidney secondary to polyarteritis nodosa.

Spontaneous rupture of the kidney occurs rarely. Among the known causes polyarteritis nodosa is uncommon with less than 50 cases reported. Diagnosis is difficult to make with certainty. Our case concerns a 38-year-old man whose symptoms originally simulated acute renal colic. Nephrectomy was done. A brief review of the pertinent literature, diagnosis and management is presented.