ONCOmmunity

An inverse relationship between KAI1 expression, invasive ability, and MMP-2 expression and activity in bladder cancer cell lines

By: You J, Madigan MC, Rowe A, Sajinovic M, Russell PJ, Jackson P.

Oncology Research Centre, Prince of Wales Hospital, Randwick, Australia and Faculty of Medicine, University of New South Wales, Kensington, Australia.
Urol Oncol. 2010 Sep 21.

Abstract

Objective

To investigate the relationship between the expression of the cancer metastasis suppressor gene KAI1 and MMP-2 and MMP-9 in human bladder cancer cell lines that express variable levels of KAI1.

Materials and methods

Five bladder cancer cell lines (BL-28/0, BL-13/0, BL-17/0/x1, B10, and D2) were grown in standard culture conditions. Gelatinase activities in serum-free conditioned medium were assessed using gelatin zymography. Whole cell lysates were prepared and Western blotting used to detect the protein expression of MMP-9, MMP-2, TIMP-1, TIMP-2, and KAI1. Semiquantitative RT-PCR was performed to analyze the mRNA expression level of MMP-2, MMP-9, TIMP-1, TIMP-2, and KAI1.

Results

Western blotting analysis confirmed that KAI1 was expressed in BL-28/0 and Bl-13/0 but not in D2, B10 and BL-17/0/x1 cell lines. This was consistent with in vitro invasion assays reported previously which showed that cell lines lacking KAI1 expression were 2x to 10x more invasive than cell lines that expressed KAI1. MMP-2 protein was detected in BL-28/0, BL-13/0. and BL-17/0/x1 only. Very low levels of MMP-9 were present in BL-28/0, BL-13/0, B10, and BL-17/0/x1 but not D2, whilst very low levels of TIMP-1 were present in all cell lines. No TIMP-2 was detected. Gelatin zymography showed detectable MMP-2 expression in conditioned medium from BL-28/0 and BL-13/0. Very weak MMP-9 was detected in BL-28/0 conditioned medium only. mRNA expression of MMP-2 was only detectable in BL-28/0 and BL-13/0 cell lines. MMP-9 mRNA levels were extremely low in all lines and not detectable in D2 cells. TIMP-1 and TIMP-2 mRNA were detected in all lines.

Conclusion

We found that KAI1 expression in bladder cancer cell lines is related to a poor invasive potential and expression of latent MMP-2 but not MMP-9. These results are unexpected given other studies showing high levels of MMP-2 and MMP-9 protein expression in patients with invasive bladder cancer. This may reflect differences in the regulation and secretion of MMP-2 and MMP-9 in vitro compared with the in vivo situation, where tumor cells interact with the surrounding environment.

PMID: 20864363 [PubMed - as supplied by publisher] Source: National Library of Medicine. Free Article