Expressions of glucose transporter genes are diversely attenuated and significantly associated with prostate cancer progression.

Abstract

Prostate cancer is a health-threaten disease in men worldwide, however, lacking is the reliable biomarkers for patient management. Aberrant metabolic events including glucose metabolism are involved in prostate cancer progression. To examine the involvement of glucose metabolic pathways in prostate cancer, we analyzed the expression profiles of glucose transporter family genes using multiple RNA-seq datasets. Our results showed that three SLC2A family genes (SLC2A4/5/9) were significantly downregulated in primary prostate cancers compared to their benign compartments. These down-regulated expressions were inversely correlated with their gene promoter methylation and genome abnormalities. Among these three SLC2A genes, only SLC2A4 showed a significantly reverse correlation with all clinicopathological parameters, including TNM stage, disease relapse, Gleason score, disease-specific survival, and progression-free interval. In addition, the expression levels of these three genes were strongly correlated with anti-cancer immune cell filtration in primary prostate cancers. In a group of patients with early-onset prostate cancers, SLC2A4 also showed a strong negative correlation with multiple clinicopathological parameters, such as tumor mutation burden, biochemical relapse, pre-surgical PSA levels, and Gleason score but a positive correlation with progression-free interval after surgery. In metastatic castration-resistant prostate cancers (CRPC), SLC2A9 gene expression but not SLC2A4 or SLC2A5 genes showed a significant correlation with androgen receptor (AR) activity score and neuroendocrinal (NE) activity score. Meanwhile, SLC2A2/9/13 expression was significantly elevated in CRPC tumors with neuroendocrinal features compared to those without NE features. On the other hand, SLC2A10 and SlC2A12 gene expression were significantly reduced in NEPC tumors compared to CRPC tumors. Consistently, SLC2A10/12 expression levels were significantly reduced in castrated animals carrying the LuCaP35 xenograft models. Survival outcome analysis revealed that SLC2A4 expression in primary tumors is a favorable prognostic factor and SLC2A6 is a worse prognostic factor for disease-specific survival and progression-free survival in prostate cancer patients. In conclusion, our results suggest that SLC2A4/6 expressions are strong prognostic factors for prostate cancer progression and survival. The significance of SLC2A2/9/13 over-expression during NEPC progression needs more investigation.