Epidermal growth factor (EGF) receptor (EGFR) signalling is implicated in tumour invasion and metastasis. However, whether there are EGFR signalling pathways specifically used for tumour invasion still remains elusive. Overexpression of Arf6 and its effector, AMAP1, correlates with and is crucial for the invasive phenotypes of different breast cancer cells. Here we identify the mechanism by which Arf6 is activated to induce tumour invasion. We found that GEP100/BRAG2, a guanine nucleotide exchanging factor (GEF) for Arf6, is responsible for the invasive activity of MDA-MB-231 breast cancer cells, whereas the other ArfGEFs are not. GEP100, through its pleckstrin homology domain, bound directly to Tyr1068/1086-phosphorylated EGFR to activate Arf6. Overexpression of GEP100, together with Arf6, caused non-invasive MCF7 cells to become invasive, which was dependent on EGF stimulation. Moreover, GEP100 knockdown blocked tumour metastasis. GEP100 was expressed in 70% of primary breast ductal carcinomas, and was preferentially co-expressed with EGFR in the malignant cases. Our results indicate that GEP100 links EGFR signalling to Arf6 activation to induce invasive activities of some breast cancer cells, and hence may contribute to their metastasis and malignancy.

Intradermal injection of phytohemagglutinin (PHA) in the wattles of chickens elicited marked swellings often accompanied by induration. Histologically, this reaction was characterized by a perivascular accumulation of lymphocytes and macrophage migration in the central layer of the wattles. Heterophilic infiltration was observed mostly at early hours and waned thereafter. Sometime basophils were prominently located around the vessels. These responses were significantly decreased in cases of neonatal thymectomy. Therefore, the PHA skin test was considered to be a thymus-dependent response. The use of the PHA skin test in chickens may provide useful information for the evaluation of thymus-dependent function.

Lung RFA is a relatively safe procedure, but it can be fatal. Risk factors found in this study will help to stratify high-risk patients.

Iatrogenic injury to the healthy ureter during ureteroscope-guided ablation of malignant or nonmalignant disease can result in ureteral stricture. Transforming growth factor (TGF)-β1-mediated scar formation is considered to underlie ureteral stricture, but the cellular sources of this cytokine and the sequelae preceding iatrogenic stricture formation are unknown. Using a swine model of ureteral injury with irreversible electroporation (IRE), we evaluated the cellular sources of TGF-β1 and scar formation at the site of injury and examined in vitro whether the effects of TGF-β1 could be attenuated by pirfenidone. We observed that proliferation and α-smooth muscle actin expression by fibroblasts were restricted to injured tissue and coincided with proliferation of macrophages. Collagen deposition and scarring of the ureter were associated with increased TGF-β1 expression in both fibroblasts and macrophages. Using in vitro experiments, we demonstrated that macrophages stimulated by cells that were killed with IRE, but not LPS, secreted TGF-β1, consistent with a wound healing phenotype. Furthermore, using 3T3 fibroblasts, we demonstrated that stimulation with paracrine TGF-β1 is necessary and sufficient to promote differentiation of fibroblasts and increase collagen secretion. In vitro, we also showed that treatment with pirfenidone, which modulates TGF-β1 activity, limits proliferation and TGF-β1 secretion in macrophages and scar formation-related activity by fibroblasts. In conclusion, we identified wound healing-related macrophages to be an important source of TGF-β1 in the injured ureter, which may be a paracrine source of TGF-β1 driving scar formation by fibroblasts, resulting in stricture formation.

Nucleotide sequences of three independently cloned repeating units of the W chromosome-specific repetitive DNA sequences ("XhoI family") of the chicken were determined. All three units are 717 bp long with XhoI sites at both ends. There are only 21 sites out of 717 bases where a single base change occurs in one of the three clones. Each of these repeating units consists of 34 tandem repeats of about 21 bp. Sequences of some members of these internal repeats are not well conserved, but the majority of the repeats are characterized by the presence of (A)3-5 and (T)3-5 clusters separated by 6-7 relatively G + C-rich base pairs. One striking feature of the cloned 717 bp repeating units is that they migrate unusually slowly on electrophoresis in polyacrylamide gels. The same feature is also shown by a genomic population of the 0.7 kb repeating units recovered from XhoI digests of the genomic DNA of the female chicken. This anomalous behavior is attributed to the occurrence of DNA curvatures because of the above sequence characteristics and partial recovery of the electrophoretic mobility in the presence of distamycin A. Another feature of the 717 bp repeating unit is the presence of 438 and 159 nucleotide-long open reading frames (ORFs) at each end of the unit. A possible function of the XhoI family sequences in the heterochromatization of the W chromosome and the significance of the ORFs are discussed.