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The importance of the Rho-GTPases in cancer progression, particularly in the area of metastasis, is becoming increasingly evident. This review will provide an overview of the role of the Rho-regulatory proteins in breast cancer metastatis.

The αvβ6 integrin is an attractive therapeutic target for several cancers due to its role in metastasis and its negligible expression in normal tissues. We previously identified a peptide from a phage-displayed peptide library that binds specifically to αvβ6. The tetrameric version of the peptide has higher affinity for its cellular targets than the corresponding monomers. However, the inefficient synthesis limits its clinical potential. We report here a convergent synthesis producing the tetrameric peptide in high yield and purity. The ease of the synthesis allows for rapid optimization of the peptide. We have optimized this αvβ6 integrin–binding peptide, determining the minimal binding domain and valency. Importantly, the half-maximal binding affinity of the optimal peptide for its target cell is in the 40 to 60 pmol/L range, rivaling the affinity of commonly used antibody-targeting reagents. This peptide mediates cell-specific uptake, is functional in diagnostic formats, is stable in sera, and can home to a tumor in an animal. We anticipate that this high-affinity ligand for αvβ6 will find clinical use as a diagnostic and therapeutic reagent.

PPH affects a larger group of individuals than previously reported. More measures should be taken to enhance the recognition, diagnosis, and treatment of PPH.

In order to display the full metastatic phenotype, the cancer cell must acquire the ability to migrate. In breast cancer, we have previously shown that insulin-like growth factor I (IGF-I) enhances cell motility in the highly metastatic MDA-231BO cell line by activating the type I IGF receptor (IGF1R). This motility response requires activation of IRS-2 and integrin ligation. In order to identify the key molecules downstream of IRS-2, we examined several signaling pathways known to be involved in cell motility. Focal adhesion kinase (FAK) was not activated by IGF-I, but IGF-I caused redistribution of FAK away from focal adhesion plaques. IGF-I treatment of MDA-231BO cells activated RhoA and inhibition of Rho-kinase (ROCK) inhibited the IGF-mediated motility response. The mitogen activated protein kinase (MAPK), p38, was also activated by IGF-I and inhibition of p38 by SB203580 blocked IGF-I induced cell motility. ROCK inhibition with Y-27632 also inhibited p38 phosphorylation suggesting that p38 lies downstream of ROCK. Both Erk1,2 and phosphatidyl-3 kinase (PI3K) were required for IGF-I stimulated cell motility, but only PI3K appeared to be directly downstream of IGF-I. Thus, IGF-I activation of its receptor coordinates multiple signaling pathways required for cell motility. Defining the key molecules downstream of the type I IGF receptor may provide a basis for optimizing therapies directed at this target.

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ObjectiveTo summarize the experience with salvage liver transplantation (SLT) for patients with recurrent hepatocellular carcinoma (HCC) after primary hepatic resection in a single center.MethodsA total of 376 adult patients with HCC underwent orthotopic liver transplantation (OLT) at Organ Transplantation Center, the First Affiliated Hospital of Sun Yat-sen University, between 2004 and 2008. Among these patients, 36 underwent SLT after primary liver curative resection due to intrahepatic recurrence. During the same period, one hundred and forty-seven patients with HCC within Milan criteria underwent primary OLT (PLTW group), the intra-operative and post-operative parameters were compared between these two groups. Furthermore, we compared tumor recurrence and patient survival of patients with SLT to 156 patients with HCC beyond Milan criteria (PLTB group). Cox Hazard regression was made to identify the risk factors for tumor recurrence.ResultsThe median interval between initial liver resection and SLT was 35 months (1–63 months). The intraoperative blood loss (P<0.05) and transfusion volume (P<0.05) were larger in the SLT group than in the PLTW group. The operation time was longer in the SLT group (P<0.05). The post-operative complications incidence, tumor recurrence rate, patients' survival rate, and tumor-free survival rate were comparable between these two groups (all P>0.05). When compared to those patients with HCC beyond Milan criteria undergoing primary OLT, patients undergoing SLT achieved a better survival and a lower tumor recurrence. Cox Proportional Hazards model showed that vascular invasion, including macrovascular and microvascular invasion, as well as AFP level >400 IU/L were risk factors for tumor recurrence after LT.ConclusionsIn comparison with primary OLT, although SLT is associated with increased operation difficulties, it provides a good option for patients with HCC recurrence after curative resection.

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