Introduction: Hyperamylasemia is an overexpression of amylase. Hyperamylasemia is associated with poor clinical outcome in ovarian cancer and reportedly serves as a prognostic biomarker for ovarian cancer. However, the function of hyperamylasemia in ovarian cancer is thus far unknown. Since amylase cleaves α1, 4-glycosidic bonds in carbohydrates, hyperamylasemia may play an active role in the etiology of ovarian cancer.
Purpose: The purpose of this study was to characterize amylase expression in ovarian cancer cell lines and establish an active role for hyperamylasemia in ovarian cancer.
Hypothesis: We hypothesized that secreted amylase enzymes cleave α1, 4-glycosidic bonds found in the carbohydrate shell which may result in a modified glycocalyx structure facilitating ovarian cancer cell invasion. Consequently, inhibiting amylase expression could abrogate ovarian cancer cell invasion/metastasis.
Methods: To characterize amylase isozyme expression, we assayed amylase expression in normal and cancerous ovarian epithelial cell lines by western immunoblot, qPCR, amylase assays and computational analyses. We measured the ability of amylase to promote cellular proliferation by MTS assays. We assayed invasive capacity of cultured cells using collagen coated Boyden chambers and abrogated amylase expression with either amylase siRNA or treatment with the blue-green algae, Spriulina.
Results: It was found that the amylase genes have identical or similar biochemical and bioinformatics properties: similar molecular weights, theoretical isoelectric points, disorder and hydropathy profiles, secondary structure and posttranslational modifications. In contrast to normal cell lines, ovarian cancer cell lines overexpress amylase at the messenger and protein levels and secrete high levels of metabolically active amylase. Amylase isozymes 1 and 2B were preferentially overexpressed in ovarian cancer cell lines. Inhibition of amylase abrogated ovarian cancer cell migration/invasion through collagen coated Boyden chambers which was associated with amylase-dependent alteration of extracellular carbohydrates. Further, the blue-green algae, Spirulina, was found to be a novel inhibitor of amylase.
Conclusion: Herein, we describe for the first time an active function of amylase to promote ovarian cancer cell invasion potentially mediated by amylase-dependent alteration of extracellular carbohydrates. Further, transcriptional inhibition of amylase by Spirulina demonstrates its clinical potential as an adjuvant nutraceutical therapy.
Citation Format: Mai Mohamed, Patricia Kruk. Amylase overexpression promotes ovarian cancer invasion. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5080.