A Novel Ferroptosis-Based Molecular Signature Associated with Biochemical Recurrence-Free Survival and Tumor Immune Microenvironment of Prostate Cancer.

Zhi-Bin Ke,Li Su,Xiao-Dong Li,Dong-Ning Chen,Ning Xu,Xue-Yi Xue,Qing-Shui Zheng,Jun-Ming Zhu,Yong Wei,Qi You,Jiang-Bo Sun

doi:10.3389/fcell.2021.774625

Abstract

Objective: To identify ferroptosis-related molecular clusters, and to develop and validate a ferroptosis-based molecular signature for predicting biochemical recurrence-free survival (BCRFS) and tumor immune microenvironment of prostate cancer (PCa). Materials and Methods: The clinical data and transcriptome data of PCa were downloaded from TCGA and GEO database. Ferroptosis-related genes (FRGs) were obtained from FerrDb database. We performed consensus clustering analysis to identify ferroptosis-related molecular subtypes for PCa. Univariate and multivariate Cox regression analysis were used to establish a ferroptosis-based signature for predicting BCRFS. Internal verification, external verification and subgroup survival analysis were then successfully performed. Results: There was a total of 40 differentially expressed FRGs in PCa. We then identified three ferroptosis-related molecular clusters of PCa, which have significantly different immune infiltrating cells, tumor immune microenvironment and PD-L1 expression level. More importantly, a novel ferroptosis-based signature for predicting BCRFS of PCa based on four FRGs (including ASNS, GPT2, NFE2L2, RRM2) was developed. Internal and external verifications were then successfully performed. Patients with high-risk score were associated with significant poor BCRFS compared with those with low-risk score in training cohort, testing cohort and validating cohort, respectively. The area under time-dependent Receiver Operating Characteristic (ROC) curve were 0.755, 0.705 and 0.726 in training cohort, testing cohort and validating cohort, respectively, indicating the great performance of this signature. Independent prognostic analysis indicated that this signature was an independent predictor for BCRFS of PCa. Subgroup analysis revealed that this signature was particularly suitable for younger or stage T III-IV or stage N0 or cluster 1-2 PCa patients. Patients with high-risk score have significantly different tumor immune microenvironment in comparison with those with low-risk score. The results of qRT-PCR successfully verified the mRNA expression levels of ASNS, GPT2, RRM2 and NFE2L2 in DU-145 and RWPE-1 cells while the results of IHC staining exactly verified the relative protein expression levels of ASNS, GPT2, RRM2 and NFE2L2 between PCa and BPH tissues. Conclusions: This study successfully identified three ferroptosis-related molecular clusters. Besides, we developed and validated a novel ferroptosis-based molecular signature, which performed well in predicting BCRFS and tumor immune microenvironment of PCa.

Highlights

As the most prevalent non-cutaneous carcinoma of males in the world, prostate cancer (PCa) is considered as the fifth leading cause of death (Xu et al, 2020a; Huang et al, 2020)
Fresh postoperative PCa tissues and benign prostatic hyperplasia (BPH) tissues were obtained from three PCa patients and three BPH patients who have been pathologically diagnosed by biopsy and were treated in the Department of Urology, the First Affiliated Hospital of Fujian Medical University
Transcriptome profiles of 499 PCa cases and 52 normal cases were downloaded from the Cancer Genome Atlas (TCGA) database

Summary

Introduction

As the most prevalent non-cutaneous carcinoma of males in the world, prostate cancer (PCa) is considered as the fifth leading cause of death (Xu et al, 2020a; Huang et al, 2020). Radical prostatectomy (RP) remains the standard curable strategy for localized PCa; there is still a certain proportion of patients developing biochemical recurrence (BCR) (Venclovas et al, 2019), which indicated a possibility of underlying clinical metastases and poor prognosis (Xu et al, 2016; Xu et al, 2020b). The early recognition of BCR is of great significance for the subsequent treatment strategies of PCa patients. With the Food and Drug Administration (FDA) approvals of sipuleucel-T into PCa treatment, immunotherapy has improved outcomes of carefully selected patients (Bilusic et al, 2017; Milonas et al, 2019). In addition to discovering the optimal treatment combination, there is an urgent need to develop potential biomarkers for immunotherapy response and tumor immune microenvironment

Methods

Results

Conclusion