pVHL co‐ordinately regulates CXCR4/CXCL12 and MMP2/MMP9 expression in human clear‐cell renal cell carcinoma

Abstract

Loss of pVHL function, characteristic for clear-cell renal cell carcinoma (ccRCC), causes increased expression of CXCR4 chemokine receptor, which triggers expression of metastasis-associated MMP2/MMP9 in different human cancers. The impact of pVHL on MMP2/MMP9 expression and their relationship to CXCR4 and its ligand CXCL12 in ccRCC is unclear. By using reverse transcription PCR, immunofluorescence and immunohistochemistry, strong mRNA and protein expression of CXCR4, CXCL12, MMP2, MMP9 and MMP inhibitors TIMP1 and TIMP2 was found in VHL-null 786-O ccRCC cells. Loss of CXCR4/CXCL12 expression after restoration of VHL function in these cells was accompanied by a significant reduction of MMP2 and MMP9 expression, whereas neither TIMP1 nor TIMP2 expression was affected. Using real-time PCR analysis, higher MMP2 (p = 0.0134) and MMP9 (p = 0.067) mRNA expression levels were detected in primary ccRCC with strong CXCR4 compared to cases with weak CXCR4 expression. There was no association between CXCR4 and TIMP1 or TIMP2 mRNA expression. MMP2 protein expression data obtained by immunohistochemistry on a tissue microarray uncovered positive cytoplasmic staining in 290/380 (76%) primary ccRCCs. Co-expression of CXCR4 and MMP2 was found in 282 of these tumours (74%). Our in vitro and in vivo data strongly indicate that pVHL coordinately regulates expression of metastasis-associated genes CXCR4/CXCL12 and MMP2/MMP9 but the exact molecular mechanism of this regulation remains to be determined. Co-expression of CXCR4 and CXCL12, as demonstrated in VHL-null 786-O cells, might enable ccRCC progression and metastatic dissemination by autocrine receptor stimulation, even in the absence of exogenous CXCL12.

JunB promotes cell invasion and angiogenesis in VHL-defective renal cell carcinoma

“…Notably, JunB-induced cell invasion was blocked by either knockdown of MMP-2 or treatment with SB-3CT in WT8 cells (Figure 7c and Supplementary Figure 7b). Previously, it was reported that pVHL regulated the expression of MMP-2 and MMP-9 (Koochekpour et al, 1999;Struckmann et al, 2008). In addition, Kurban et al (2006) clearly showed that MMP-2 was regulated by pVHL in an HIF-independent manner in 786-O cells.…”

Onconeuronal cerebellar degeneration-related antigen, Cdr2, is strongly expressed in papillary renal cell carcinoma and leads to attenuated hypoxic response

“…Papillary renal cell carcinoma expresses high Cdr2 protein levels and show attenuated expression of HIF-target genes To analyse Cdr2 protein levels in human tumors, we performed immunohistochemistry analysis on 162 benign and malignant specimens of 20 different organs and 12 distinct cell lines using tissue microarray (TMA) technology (Kononen et al, 1998;Struckmann et al, 2008). As expected, Cdr2 staining was observed in brain, as well as in testis samples, and somewhat weaker in breast and ovary tumors, but quite surprisingly, the most intense Cdr2 protein signals were found in RCC (data not shown).…”

Matrix metalloproteinase-2 and -9 in the sera and in the urine of human oncocytoma and renal cell carcinoma

“…Among protein markers, MMP-2 and MMP-9 have been investigated with variable results. Tissue MMP-2 and MMP-9 were found to be overexpressed in tumors and more frequently in non-ccRCC (16,17). In particular, by immuno chemistry Kallakury et al (17) found overexpression of MMP-2 and MMP-9 in 43% of tumors and this increased expression correlated with poor prognostic variables.…”