Abstract LB-308: Hypoxia affects gene expression and proteome of prostate cancer cells

Abstract

Abstract Tumor-associated hypoxia facilitates malignant progression, metastasis and poor prognosis in prostate cancer (CaP); however, effects of oxygen tension (pO2) in CaP are just beginning to be investigated. To establish mechanisms whereby hypoxia enhances malignant properties and survival of CaP and to identify pO2-regulated tumor-associated macromolecules, we propagated CaP cell lines LnCaP, VCaP and DU145 in hypoxia (pO2=2 kPa) and compared them with normoxically grown cells (pO2=20 kPa); hypoxic cells proliferated faster and secreted more vascular endothelial growth factor (p<0.05). Transcriptome studies revealed different gene expression in cells grown in hypoxia relative to those in normoxia. Interestingly, in hypoxic cells transcripts associated with cancer and urologic disease were overexpressed in comparison to normoxic cells (p<0.001) suggesting an association of low pO2 and aggressive features of CaP. Further, we analyzed the transcriptome in primary CaP cells isolated by laser-capture microdissection (LCM) and whole CaP tissue. We compared the data to those from CaP cells cultured at pO2=20 kPa or pO2=2 kPa. Notably, hypoxia increased transcript levels for pyruvate dehydrogenase kinase isozyme 1, nuclear prelamin A recognition factor, glucose phosphate isomerase, and glyceraldehyde-3-phosphate dehydrogenase in all three cell lines (p<0.05) to levels comparable to those found in primary bulk tissue and LCM isolated cells (p<0.005). This finding suggests that gene expression in hypoxically cultured cells is more akin to that in tumor cells in situ than are cells grown normoxically. By 2D-gel electrophoresis, we found that change in pO2 affected the proteome mostly quantitatively (i.e., by change in spot intensity). Our results suggest that hypoxia affects transcriptome and proteome in CaP cells. In addition, we screened 20 patient sera and 20 healthy control sera for spontaneous antibodies cross-reactive with VCaP cells and found that the sera reacted with numerous proteins, some previously reported to elicit an immune response in CaP patients (e.g., nucleoporin 62 and transitional endoplasmic reticulum ATPase). By this method we detected numerous novel autoantigens (under validation). Currently we are clarifying the pO2 effects on the relationship of transcriptome, proteome and tumor-associated antigens in CaP cells. Support: DOD PC094680 (CRG), Minnesota Partnership for Biotechnology and Medical Genomics, Mayo Clinic Prostate SPORE 5P50CA091956 (FK); Mrs. Adelyn L. Luther, Singer Island, Florida and Mayo Clinic Cancer Center (SV-P). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-308. doi:10.1158/1538-7445.AM2011-LB-308