Ulrike Lacher

Role of MT‐MMPs and MMP‐2 in pancreatic cancer progression

Activation of matrix metalloproteinase‐2 (MMP‐2) by the membrane‐type matrix metalloproteinases (MT‐MMPs) has been associated with tumor progression. In the present study, we examined the role of MMP‐2 and its activators MT1‐MMP, MT2‐MMP and MT3‐MMP in pancreatic tumor cell invasion and the development of the desmoplastic reaction characteristic of pancreatic cancer tissues. Northern blot analyses revealed that transcript levels of MT1‐MMP and MT2‐MMP, but not MT3‐MMP, were enhanced in pancreatic cancer tissues (n = 18) compared with both chronic pancreatitis (n = 9) and healthy pancreas (n = 9). A good correlation was found between MT1‐MMP and both MMP‐2 expression (p < 0.01) and activity in pancreatic cancer tissues. In addition, expression and activation of MMP‐2 were strongly associated with the extent of the desmoplastic reaction in pancreatic cancer tissues. Invasion assays showed a good correlation between MMP‐2 expression and activity and the invasive potential of pancreatic cancer cell lines. In cell lines with high levels of MMP‐2 expression and activity, the MMP inhibitor Batimastat led to significant reduction of the number of invading cells. Our results suggest that MT1‐MMP is involved in the progression of pancreatic cancer via activation of MMP‐2. MMP‐2 itself plays an important role in tumor cell invasion and appears to be associated with the development of the characteristic desmoplastic reaction in pancreatic cancer. Int. J. Cancer 85:14–20, 2000.

Expression of the highly conserved RNA binding protein KOC in embryogenesis.

The human KOC gene which is highly expressed in cancer shows typical structural features of an RNA binding protein. We analyzed the temporal and spatial expression pattern of KOC in mouse embryos at different gestational ages. The expression of KOC seems to be ubiquitous at early stages. During advanced gestation highest KOC expression occurs in the gut, pancreas, kidney, and in the developing brain. The expression pattern of KOC was compared to its Xenopus homologue Vg1-RBP during frog development. Similar expression was found in these organs suggesting an important functional role of the homologous proteins in embryonic development.

Identification of genes with specific expression in pancreatic cancer by cDNA representational difference analysis

cDNA representational difference analysis (cDNA‐RDA) is a polymerase‐chain‐reaction‐coupled subtractive and kinetic enrichment procedure for the isolation of differentially expressed genes. In this study, the technique was used to isolate novel genes specifically expressed in pancreatic cancer. cDNA‐RDA was done on cDNA reverse transcribed from a poly(A)+ mRNA pool made from 10 cancer tissues (tester) by using as a driver a cDNA from a poly(A)+ mRNA pool made from a combination of 10 tissues of chronic pancreatitis and 10 healthy pancreatic tissues. The use of chronic pancreatitis in addition to healthy pancreas mRNA in the driver preparation eliminated the influence of stromal tissue components present as contamination in the cancer‐specific preparations. Such cDNA‐RDA led to the isolation of 16 distinct, cancer‐specific gene fragments. These were confirmed to be overexpressed in pancreatic cancer tissues by Northern blot analysis. Sequence analysis revealed homologies to five genes previously implicated in the carcinogenesis of the pancreas or other tissues. Eleven fragments had no significant homology to any known gene and thus represent novel candidate disease genes. The experiments demonstrate that cDNA‐RDA is a reproducible and highly efficient method for the identification of novel genes with cancer‐specific expression. Genes Chromosom. Cancer 19:97–103, 1997.

KOC is a novel molecular indicator of malignancy.

The detection of malignant cells in fine-needle aspirates (FNAs) using marker genes is hampered by the fact that these markers are only expressed by certain malignancies or lack sensitivity and/or specificity. Here we report the results of a prospective pilot study examining the expression of KOC (KH-domain containing protein over expressed in cancer), a novel onco-foetal gene, in 76 patients who underwent fine-needle aspiration for further diagnosis of abdominal lesions, aszites, cysts or cerebrospinal fluid. Aspirates were examined by cytology and by a KOC RT–PCR assay. KOC expression was a highly sensitive and specific indicator of malignancy. The KOC assay could be useful to facilitate screening for malignant disease and to improve the diagnostic accuracy of FNAs.