Transcript analyses of stromal cell derived factors (SDFs): SDF-2, SDF-4 and SDF-5 reveal a different pattern of expression and prognostic association in human breast cancer

Stromal derived factors, SDFs, are a loosely defined group of molecules that may be generated by stromal cells. Two of the stromal derived factors, SDF-1 and SDF-4 belong to the chemokine family. Other SDFs, such as SDF-2 and SDF-5 are not well defined and their biological functions are less known. Although SDF-1 and its receptor have been strongly indicated in the progression of various cancers including breast cancer, little is known with regard to the role of other SDFs in malignant conditions including breast cancer. In the present study, we analysed the pattern of expression of SDF-2, SDF2-like-1, SDF-4 and SDF-5 in breast cancer tissues and cells, at transcript and protein levels. It was found that SDF-2, SDF2-L1, SDF-4, and SDF-5 were ubiquitously expressed in various cancer cell lines. However, in clear contrast to SDF-1 whose over-expression has been shown to be linked to a poor clinical outcome, the present study provides evidence that the opposite appear to be true for SDF-2/SDF2-L1, SDF-4 and SDF-5. Significantly low levels of SDF-2 and SDF-4 were seen in patients with poor clinical outcome (with metastatic disease and death as a result of breast cancer, p<0.05, and p<0.01 respectively), when compared with patients who remained disease-free. SDF2-L1 and SDF-5 showed a similar trend. SDF-2 and SDF-L1 were also independent prognostic indicators (p=0.047 and p=0.012, respectively). It is concluded that SDF-2, SDF-4 and SDF-5 are expressed in mammary tissues and cells and that a reduced level of SDF-2, SDF2-L1 and SDF-4 are associated with a poor clinical outcome. These SDFs thus have prognostic value and warrant further investigation in their biological functions and clinical value

Coordinating the impact of structural genomics on the human α-helical transmembrane proteome

Given the recent successes in determining membrane-protein structures, we explore the tractability of determining representatives for the entire human membrane proteome. This proteome contains 2,925 unique integral α-helical transmembrane-domain sequences that cluster into 1,201 families sharing more than 25% sequence identity. Structures of 100 optimally selected targets would increase the fraction of modelable human α-helical transmembrane domains from 26% to 58%, providing structure and function information not otherwise available

Claudin-5 is involved in breast cancer cell motility through the N-WASP and ROCK signalling pathways

Abstract Background Recent studies have shown dysregulation in TJ structure of several cancers including breast. Claudin-5 is a protein member of the TJ structure expressed in both endothelial and epithelial cells. This study examined the level of expression and distribution of Claudin-5 in human breast cancer tissues and the effect of knockdown and forced expression of Claudin-5 in the MDA-MB-231 breast cancer cell line. Methods Immunohistochemistry and quantitative-PCR were used to analyse patient tissue samples. The Claudin-5 gene was cloned and overexpressed or knocked down using ribozyme technology in human breast cancer cells. Changes in function were assessed using in vitro assays for invasion, growth, adhesion, wounding, motility, transepithelial resistance and electric cell-substrate impedance sensing. Changes in cell behaviour were achieved through the use of Hepatocyte Growth factor (HGF) which we have shown to affect TJ function and expression of TJ proteins. In addition, an in vivo model was used for tumour growth assays. Results data was analyzed using a Students two sample t-test and by Two-way Anova test when the data was found to be normalized and have equal variances. In all cases 95% confidence intervals were used. Results Patients whose tumours expressed high levels of Claudin-5 had shorter survival than those with low levels (p = 0.004). Investigating in vitro the effect of altering levels of expression of Claudin-5 in MDA-MB-231cells revealed that the insertion of Claudin-5 gene resulted in significantly more motile cells (p  Conclusions This study portrays a very new and interesting role for Claudin-5 in cell motility involving the N-WASP signalling cascade indicating a possible role for Claudin-5 in the metastasis of human breast cancer.</p

The novel complement inhibitor CMSD1 protein promotes Factor I-mediated degradation of C4b and C3b and inhibits MAC assembly and C9 polymerisation

CUB and Sushi multiple domains 1 (CSMD1) is a transmembrane protein formed from 14 N-terminal CUB domains separated by single complement control protein (CCP) domains and followed by a tandem repeat of 15 CCP domains which are characteristic for complement inhibitors. Therefore, shares homology with a number of proteins involved in many cellular processes such as growth, cell adhesion, cancer progression and in controlling the complement system. It was firstly identified as a candidate tumour suppressor gene of unknown function. By using a panel of healthy adult human samples, Q-PCR data revealed that CSMD1 is mainly found in testis, cerebellum, cerebral cortex and brain white matter. A high expression profile was also observed in fetal brain tissue. We expressed a soluble protein containing CCP domains 17–21 together with Fc-tag. The expression of this construct significantly decreased deposition of C4b and C3b on transfected mammalian cells and showed cofactor activity to FI. Furthermore, CSMD1 CCP 17–21 Fc inhibited MAC formation at the level of C7 and the polymerisation of C9, both when self-polymerisation of C9 was studied but also on the surface of erythrocytes in the presence of human serum. Moreover, reduction of expression in the T47 breast cancer cell line that expresses endogenous CSMD1, significantly increased C3b deposition on the surface. Considering that CSMD1 is frequently deleted in cancer, loss of CSMD1 and consequently loss of local complement inhibition may lead to inflammation, thus providing an ideal environment for cancer development