(a) Screening

of different human tissues for Claudin-5 coding sequence at mRNA level using RT-PCR. β-actin is used as a loading control. The placenta tissue was selected as a template. (b) Verification of Claudin-5 over-expression and knockdown in MDA-MB-231cells. Claudin-5 levels were higher in MDA-MB-231 CL5exp compared to the controls, as seen at mRNA level using RT-PCR. Claudin-5 expression was reduced in MDA-MB-231 CL5rib2 when ribozyme 2 was used, at mRNA level using RT-PCR. (c) Protein level using Western blot analysis to show expression of Claudin-5. (d) Immunofluorescence staining showing the distribution of Claudin-5 in Overexpressing cells (left) with Phalloidin to show actin (centre)

and merged (right). In order to determine whether low levels of Claudin-5 has an effect on cells; ribozyme transgenes were generated to down-regulate Claudin-5 https://www.selleckchem.com/products/bi-d1870.html expression in this cell line. Two Claudin-5 targeting ribozyme, ribozyme 1 and ribozyme PF-02341066 ic50 2, were transfected into the cells together with an empty plasmid. Claudin-5 knockdown was verified at both mRNA and protein levels using RT-PCR and Western blotting (Figure 3c). However, ribozyme 1(MDACL5rib1) was unsuccessful in knockdown of Claudin-5 expression; therefore only the cells expressing low levels of Claudin-5 are further referred to as MDACL5rib2. The MDACL5rib2 cells demonstrated Resveratrol reduced mRNA and protein levels of Claudin-5 compared to the controls, MDAWT and MDApEF6. Immunostaining revealed some increase in Claudin-5 at the cell periphery (Figure 3d). Claudin-5 did not alter cell growth in transfected human breast cancer cells The MDA-MB-231 sublines MDACl5exp and MDACL5rib2 alongside MDApEF6 were examined following 1, 3 and 4 day incubation periods using an in vitro cell growth assay.

No significant difference in the in vitro growth rate of the MDApEF6 cells compared to MDACl5exp or MDACL5rib2 were found following the three different incubation periods (Figure 4a). Figure 4 In vitro effect of Claudin-5 expression on and in vivo tumor development of MDA-MB-231 cells. (a) The cell growth of MDACl5exp and MDACL5rib2 did not show any significant difference when compared to MDApEF6 (mean ± SD, n = 3). (b) The adhesive capacity of MDACL5rib2 was significantly decreased in comparison with the control MDApEF6 (p ≤ 0.001) (mean ± SD, n = 3). (c) The invasive capacity of MDACl5exp and MDACL5rib2 did not show any significant difference when compared to MDApef6 (mean ± SD, n = 3). (d) There were no significant differences in tumor growth over 33 day period (p = 0.29). (e) A significant increase was seen in TER of MDACL5rib2 over a period of 4 hours when compared to the control (p ≤ 0.001) (mean±SD, n = 3).