Shotgun proteomic analysis of human head and neck squamous cell carcinoma cell line SQ20B with diminished AHSG expression

Background The Alpha-Heremans-Schmid Glycoprotein (AHSG) has tumor promoting properties in animal models of breast cancer and lung cancer [1,2]. These cancer cells do not synthesize AHSG, instead utilizing the liver-generated glycoprotein that is abundant in serum. We have reported that head and neck squamous cell carcinoma (HNSCC) cell lines synthesize AHSG (in press) and have also detected abundant AHSG in primary HNSCC tumors (unpublished). Growth in serum-free medium and in vitro tumorigenic properties, including proliferation, adhesion and migration, are diminished in the HNSCC SQ20B cell line modified with AHSG-specific shRNA to express only twenty percent of the wild-type SQ20B cell line (SQ20B-AH20) compared to SQ20B modified with empty vector alone and expressing the wild-type amount of AHSG (SQ20B-EV) [3]. Here we have used shotgun proteomic analysis to identify additional proteins whose expression may also affect these in vitro properties of tumorigenesis associated with AHSG.