Role of IGF-1/IGF-1R in regulation of invasion in DU145 prostate cancer cells

Zeina Saikali¹^,3 , Hemani Setya¹^,3 , Gurmit Singh¹^,3 and Sujata Persad¹^,2^,4

¹Department of Research, Juravinski Cancer Centre, Hamilton, Canada

²Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada

³Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada

⁴Presently at: Department of Pediatrics, University of Alberta, Edmonton, Canada

author email corresponding author email

Cancer Cell International 2008, 8:10doi:10.1186/1475-2867-8-10


Published:	3 July 2008

Abstract

Background

Prostate cancer progression to androgen independence is the primary cause of mortality by this tumor type. The IGF-1/IGF-1R axis is well known to contribute to prostate cancer initiation, but its contribution to invasiveness and the downstream signalling mechanisms that are involved are unclear at present.

Results

We examined the invasive response of androgen independent DU145 prostate carcinoma cells to IGF-1 stimulation using Matrigel assays. We then examined the signaling mechanisms and protease activities that are associated with this response. IGF-1 significantly increased the invasive capacity of DU145 cells in vitro, and this increase was inhibited by blocking IGF-1R. We further demonstrated that specific inhibitors of the MAPK and PI3-K pathways decrease IGF-1-mediated invasion. To determine potential molecular mechanisms for this change in invasive capacity, we examined changes in expression and activity of matrix metalloproteinases. We observed that IGF-1 increases the enzymatic activity of MMP-2 and MMP-9 in DU145 cells. These changes in activity are due to differences in expression in the case of MMP-9 but not in the case of MMP-2. This observation is corroborated by the fact that correlated changes of expression in a regulator of MMP-2, TIMP-2, were also seen.

Conclusion

This work identifies a specific effect of IGF-1 on the invasive capacity of DU145 prostate cancer cells, and furthermore delineates mechanisms that contribute to this effect.