[Correlation of expression of RhoC with invasiveness of prostate cancer cell line PC-3M in vitro].

Objective: To investigate the expression of RhoC in prostate cancer cells with different metastatic potential and the correlation with invasiveness.
Methods: Expression of RhoC mRNA and protein in human prostate cancer cell subclones PC-3M-2B4 with non-metastatic potential and PC-3M-1E8 with highly metastatic potential was detected by RT-PCR and Western blot. Eukaryotic expression plasmids of RhoC were constructed and transfected into PC-3M-2B4. The biological effects were observed, including in vitro invasion by Boyden chamber assay, motility by would healing assay, alteration of microfilament network by the staining of TRTIC-phalloidin, activities of matrix metalloproteinases (MMP) by gelatin zymography analysis and expression of p-Akt by Western blot assay.
Results: The expression levels of RhoC mRNA and protein varied in the two different metastatic subclones of human prostate cancer cell. RhoC was significantly upregulated in the highly metastatic subclones in comparison to the nonmetastatic counterpart (P < 0.01). As shown in Boyden chamber assay, the invasive capacity of transfected cells overexpressing RhoC was significantly promoted as reflected by more penetrating cells (125.21 +/- 10.43) than the antisense transcripts (46.22 +/- 8.12), the negative (53.77 +/- 8.56) and blank controls (57.68 +/- 7.25). Further study by would healing assay indicated that cells overexpressing RhoC were more motile in actin-based active movement (would healing ratio after 16 h of the sense transcripts, antisense transcripts, negative controls and blank controls was 62.38 +/- 2.36, 29.47 +/- 1.86, 32.23 +/- 2.43, 31.88 +/- 2.67 respectively). The TRITC-phalloidin staining revealed less actin filament bundles and a fuzzy network of shorter filaments in the sense transcripts. In addition, MMP-2 activity and p-Akt expression level were upregulated in the sense transcripts.
Conclusion: RhoC overexpression could promote the invasive capacity of human prostate cancer cell in vitro and it's expression level correlated positively with the metastatic capacity of human prostate cancer cell, so RhoC may be a potential target in the development of a novel strategy for treating metastasis of prostate cancer.