Mehmet Gunduz

Heparanase expression correlates with malignant potential in human colon cancer

Purpose Heparanase cleaves carbohydrate chains of heparan sulphate proteoglycans and is an important component of the extracellular matrix. This study was designed to determine the relation between heparanase expression and prognosis of patients with colon cancer.Methods The study included 54 patients (35 males and 19 females) who underwent colorectal resection for colorectal cancer between January 1992 and December 1994. Expression of heparanase protein and mRNA were determined and correlated with various clinicopathological parameters. In vitro studies were also performed to examine tumor invasion and to test the effects of heparanase inhibition, and in vivo studies were performed to examine tumor metastasis and prognosis.Results Heparanase expression was detected in the invasion front of the tumor in 37 of 54 (69%) colon cancer samples, whereas 17 of 54 (31%) tumors were negative. Expression of heparanase was significantly more frequent in tumors of higher TNM stage (P=0.0481), higher Dukes stage (P=0.0411), higher vascular infiltration (P=0.0146), and higher lymph vessel infiltration (P=0.0010). Heparanase expression in colon cancers correlated significantly with poor survival (P=0.0361). Heparanase-transfected colon cancer cells exhibited significant invasion compared with control-transfected colon cancer cells (P=0.001), and the peritoneal dissemination model also showed the malignant potential of heparanase-transfected cells, as assayed by number of nodules (P=0.017) and survival (P=0.0062). Inhibition of heparanase significantly reduced the invasive capacity of cancer cells (P=0.003).Conclusions Heparanase is a marker for poor prognosis of patients with colon cancer and could be a suitable target for antitumor therapy in colon cancer.

Heparanase Is Involved in Angiogenesis in Esophageal Cancer through Induction of Cyclooxygenase-2

Purpose: Both heparanase and cyclooxygenase-2 (COX-2) are thought to play critical roles for tumor malignancy, including angiogenesis, although it is unknown about their relationship with each other in cancer progression. We hypothesized that they may link to each other on tumor angiogenesis. Experimental Design: The expressions of heparanase and COX-2 in 77 primary human esophageal cancer tissues were assessed by immunohistochemistry to do statistical analysis for the correlation between their clinicopathologic features, microvessel density, and survival of those clinical cases. Human esophageal cancer cells were transduced with heparanase cDNA and used for reverse transcription-PCR and Western blot to determine the expression of heparanase and COX-2. COX-2 promoter vector and its deletion/mutation constructs were also used along with transduction of heparanase cDNA for luciferase assay. Results: Heparanase and COX-2 protein expression exhibited a similar pattern in esophageal tumor tissues, and their expression correlated with tumor malignancy and poor survival. Their expression also revealed a significant correlation with high intratumoral microvessel density. Up-regulation of COX-2 mRNA and protein was observed in esophageal cancer cells transfected with heparanase cDNA. COX-2 promoter was activated after heparanase cDNA was transduced and the deletion/mutation of three transcription factor (cyclic AMP response element, nuclear factor-κB, and nuclear factor-interleukin-6) binding elements in COX-2 promoter strongly suppressed its activity. Conclusion: Our results suggest that heparanase may play a novel role for COX-2-mediated tumor angiogenesis.

Translocation of heparanase into nucleus results in cell differentiation.

We recently reported that heparanase, one of the extracellular matrix‐degrading enzymes, which plays a critical role in cancer progression, is located not only in the cytoplasm but also in the nucleus. Here we identified nuclear translocation of heparanase as a key step in cell differentiation. We applied an in vitro differentiation model of HL‐60 cells with 12–0‐tetradecanoylphorbol‐13‐acetate (TPA), in which nuclear translocation of heparanase was observed using immunohistochemical analysis. In this system, nuclear translocation of heparanase was abolished by inhibitors of heat shock protein 90 (HSP90), suggesting the involvement of HSP90 in translocation of heparanase. We further confirmed that overexpression of active form of heparanase induced differentiation of HL‐60 cells, although the catalytic negative form of heparanase did not. Therefore we speculate that nuclear translocation of enzymatically active heparanase may be involved in cellular differentiation. Our results suggest that a novel function of heparanase upon cell differentiation would raise a potential new strategy for cancer therapy of promyeloid leukemia and other types of cancer. (Cancer Sci 2007; 98: 535–540)

Immunolocalization and distribution patterns of type IV collagen alpha chains in oral mucosal melanoma

The basement membrane (BM) is mainly composed of type IV collagen, which is composed of triple combinations of six distinct alpha (α) chains in a tissue-specific manner. The six collagen chain-specific antibodies (α1–α6) were used to examine the BMs of the oral epithelium (OE) and tumor clusters in oral mucosal melanoma (OMM). Eight OMM cases were examined. Results showed that the α1 and α2 chains were constantly detected at the BM of the normal OE as well as at the OE with atypical melanocytic proliferation and in invasive melanoma with nodular nests. The α1 and α2 chains were intermittently detected in in situ OMM, early invasive OMM and advanced invasive OMM with sheet-like nests. Gradual loss of α5 and α6 from the OE with atypical melanocyte through in situ OMM and early invasive OMM was observed. These findings suggest that changes in the immunolocalization and distribution patterns of type IV collagen α chains are associated with the progression of OMM. The distribution pattern of type IV collagen α chain varies depending on the architecture of the nest.

Functions of the Tumor Suppressor ING Family Genes

ING1 gene, the founding member of the ING tumor suppressor family, was originally identified through subtractive hybridization between normal mammary epithelial cells and breast cancer cell lines, and subsequent in vivo selection of genetic suppressor element that displayed oncogenic features. The four additional members of the ING family (ING2-5) were recently identified and all the gene products contain a highly conserved plant homeodomain (PHD) finger motif in the carboxy (C)-terminal end. Although exact functions of ING family genes have not been clarified, the gene products are involved in transcriptional regulation, apoptosis, cell cyle, angiogenesis and DNA repair through p53-dependent and -independent pathways and constituting complexes with histone acetyltransferases (HAT) and histone deacetylases (HDAC). This review summarizes the known biological functions of the ING tumor suppressors and signaling pathways that they involve.