Three PCR assays for diagnosing leishmaniasis were compared and validated against parasite cultures and microscopic evaluation of stained tissue smears using 92 specimens from suspected cases of cutaneous leishmaniasis (CL) in Israel and the West Bank. Samples from imported and locally acquired disease were examined. The kinetoplast DNA (kDNA) PCR showed the highest sensitivity (98.7%) of any assay, correctly diagnosing 77/78 of the confirmed positive samples, followed by the rRNA gene internal transcribed spacer 1 (ITS1) PCR (71/78 positive, 91.0% sensitivity) and then the spliced leader mini-exon PCR (42/78 positive, 53.8% sensitivity). Either parasite culture or microscopy alone detected 62.8% (49/78) or 74.4% (58/78) of the positive specimens, respectively, while culture and microscopy together improved overall sensitivity to 83.3% (65/78). Except for the kDNA PCR that had six false positives, all other assays were 100% specific. Further, restriction enzyme analysis of the ITS1 PCR product enabled identification of 74.6% of the positive samples, which included strains of Leishmania major (50.9%), Leishmania tropica (47.2%), and the Leishmania braziliensis complex (1.9%). This suggests that a PCR using kDNA should be used for the diagnosis of CL and that an ITS1 PCR can be reliably used for the diagnosis of CL when rapid species identification is needed.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease that is closely associated with colon cancer. Here we report that heparanase enzyme acts as an important mediator of colitis-associated tumorigenesis. Heparanase is an only known mammalian enzyme that cleaves heparan sulfate, the major polysaccharide of the extracellular matrix, and plays multiple roles in inflammation and cancer progression. Applying histological specimens from UC patients and a mouse model of dextran sulfate sodium (DSS)-induced colitis, we found that heparanase is constantly overexpressed and activated during the course of the disease, both in the active and inactive phases of inflammation. Employing heparanase-overexpressing transgenic mice in the model of colitis-associated cancer, induced by carcinogen azoxymethane followed by repeated DSS administration, we demonstrated that heparanase overexpression markedly increased the incidence and severity of colitis-associated colonic tumors, enabling faster tumor take, angiogenic switch and enhanced tumor progression. Notably, DSS-induced colitis alone (without azoxymethane pretreatment) lead to formation of colonic tumors in heparanase-transgenic, but not wild type mice, positioning heparanase as important physiological determinant in inflammation-driven colon carcinoma, replacing the need for carcinogen. Investigating molecular mechanisms underlying heparanase induction in colitis, we found that TNF-alpha is responsible for continuous overexpression of heparanase by chronically-inflamed colonic epithelium. Moreover, our results suggest the occurrence of heparanase-driven vicious cycle that powers colitis and associated tumorigenesis: heparanase activity in inflamed colon, acting synergistically with the local cytokine milieu, stimulates macrophage activation, and the activated macrophages secrete TNF-alpha which stimulate further production of heparanase by colonic epithelium. In addition, activated macrophages secrete cathepsin L - a cysteine protease responsible for proteolytic activation of latent heparanase enzyme. Altogether, our results identify heparanase as a key factor in pathogenesis of colitis-associated cancer and attest the inhibition of heparanase as a promising mean to disrupt the vicious cycle that fuels chronic colitis and the associated tumorigenesis. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C251.

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