Schistosoma haematobium total antigen induces increased proliferation, migration and invasion, and decreases apoptosis of normal epithelial cells

Schistosome worms are blood-dwelling flukes that cause chronic infection in more than 200 million people and are thought to be responsible for 500,000 deaths annually. During infection with Schistosoma haematobium, eggs are deposited in the mucosa and submucosa of the bladder and lower ureters. Squamous cell carcinoma (SCC) of the bladder is a long-term sequela of chronic infection. The mechanisms underlying the association between S. haematobium and SCC of the bladder are largely unknown, with all reports to date exclusively demonstrating epidemiological evidence linking S. haematobium infection with SCC of the bladder. We hypothesised that the parasite antigens might induce alterations in epithelial cells towards cancer. For this we used Chinese Hamster Ovary (CHO) cells and treated the cells in culture with S. haematobium total antigen (Sh). Our results showed increased proliferation, increased S-phase and decreased apoptosis, as well as down-regulation of tumour suppressor p27 and up-regulation of anti-apoptotic molecule Bcl-2 in Sh-treated cells compared with controls. We also found increased migration and invasion. To our knowledge, this is the first report demonstrating alterations of normal epithelial cells as a direct effect of S. haematobium antigens.