The serine protease stratum corneum chymotryptic enzyme (kallikrein 7) is highly overexpressed in squamous cervical cancer cells

Abstract

Objective. To determine whether the Stratum Corneum Chymotryptic Enzyme (SCCE), a novel serine protease known to contribute to the cell shedding process by catalyzing the degradation of intercellular cohesive structures at the skin surface, is overexpressed in human cervical tumors. Methods. SCCE expression was evaluated in 18 cervical cancer cell lines (i.e., 10 primary and 8 established cell lines) as well as in 8 normal cervical keratinocyte cultures by RT-PCR. In addition, SCCE expression was evaluated by immunohistochemistry on paraffin-embedded tumor tissue. Results. Normal cervical keratinocytes did not express SCCE. In contrast, 50% of the primary and 50% of the established cervical cancer cell lines expressed SCCE by RT-PCR. Eighty percent (i.e., four of five) of primary squamous cervical tumors and 20% (i.e., one of five) of primary adenocarcinomas expressed SCCE. Five out of five (100%) of the patients harboring SCCE-positive tumors were found to have metastatic involvement of the pelvic tumor draining lymph nodes. Immunohistochemistry staining of paraffin-embedded cervical cancer specimens confirmed SCCE expression in tumor cells and its absence on normal cervical epithelial cells. Conclusion. Squamous cervical cancer expressed high levels of SCCE, suggesting that this protease may play an important role in invasion and metastasis. Because SCCE appears only in abundance in tumor tissue and contains a secretion signal sequence, suggesting that SCCE is secreted, it may prove to be a useful diagnostic/prognostic tool for the detection of metastatic or recurrent disease or as a novel molecular target for cervical cancer therapy.