https://orcid.org/0000-0002-1596-5505
Abstract
Background
Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world with an immunosuppressive Tumor microenvironment (TME). Ferroptosis plays an essential role in tumor proliferation, invasion, and metastasis. However, the relationship between ferroptosis and TME of HCC has remained elusive.
Methods
Differentially expressed ferroptosis-related genes (DE FRGs) between normal liver tissues and HCC tissues were obtained from The Cancer Genome Atlas (TCGA). On this basis, we identified the molecular subtypes mediated by DE FRGs and TME cell infiltration. Next, a predictive signature was established to quantity the ferroptosis-related characteristics by performing the least absolute shrinkage and selection operator Cox regression analyses. Univariate and multivariate COX analyses determined the independent prognostic factors. Finally, the expression stability of 3 ferroptosis-related signature genes was verified in cancer and paracancerous normal tissues of HCC.
Results
We identified three different molecular subtypes and found that the subtype with the better prognosis was associated with high enrichment of immune- and metabolic-related hallmark signaling pathways and high infiltration of immune cells in TME. The signature was considered to be an independent prognostic factor. We also found that the signature can reflect the infiltration characteristics of different immune cells in TME. Immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs), regulatory T cells, and type 17 T helper cells were significantly enriched in the high-risk group. The analysis data of immune checkpoints and tumor mutation load indicated that the signature had great potential in predicting Immunotherapy response and chemotherapeutic sensitivity. In addition, the overexpression of 3 ferroptosis-related signature genes was confirmed in HCC tissues and HCC cell lines. Ferroptosis inducer RSL3 inhibited the proliferation of HCC cells and was a potential cancer immunotherapy agent.
Conclusion
These findings enhanced our understanding of the regulatory mechanism of ferroptosis in HCC and provided new insights into evaluating prognosis and developing more effective Immunotherapy and chemotherapy strategies.
Abbreviations
HCC, Hepatocellular carcinoma; TME, tumor microenvironment; DE FRGs, differentially expressed ferroptosis-related genes; MDSCs, myeloid-derived suppressor cells; ICIs, Immune checkpoint inhibitors; GSH, peptide glutathione; Gpx4, Glutathione-peroxidase; TMB, Tumor mutational burden; CTLs, cytotoxic T lymphocytes; DAMPs, damage-associated molecular pattern; FRGs, ferroptosis-related genes; TCGA, The Cancer Genome Atlas; CNV, copy number variation; DEGs, differentially expressed genes; FC, fold change; CDF, distribution function; GSVA, gene set variation analyses; ssGSEA, single sample gene set enrichment analysis; OS, overall survival; LASSO, the least absolute shrinkage and selection operator; AUC, area under the curve; qRT-PCR, quantitative Real-Time Polymerase Chain Reaction; GO, gene ontology; ROC, receiver operating characteristic curve; DCA, decision curve analysis; IC50, semi-inhibitory concentration; DCs, dendritic cells; Tregs, regulatory T cells; TAMs, tumor-associated macrophages; ROS, reactive oxygen species.
Data Sharing Statement
Publicly available datasets were analyzed in this study; these can be found in The Cancer Genome Atlas (TCGA) (https://portal.gdc.cancer.gov/) and GSE14520 (https://www.ncbi.nlm.nih.gov/geo/).
Ethics Approval and Consent to Participate
The tissue samples of HCC patients used in the present study were approved by the Ethics Committee of Zhongnan Hospital of Wuhan University. Written informed consent was obtained from all patients (grant number #20200110). The study was performed and reported in accordance with the Helsinki Declaration.
Acknowledgments
Chunlan Zheng and Yanan Peng are co-first authors for this study. Lan Liu and Qiu Zhao are co-correspondence authors for this study.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed to submit to the current journal; and agree to be accountable for all aspects of the work.
Disclosure
The authors declare that they have no competing interests in this work.