STAD is one of the common malignant tumours in China today. Despite the continuous development of modern medicine, there are various modalities such as surgery, radiotherapy, targeted therapy and immunotherapy that can be used to treat and improve the survival and prognosis of patients with STAD, the prognosis of advanced refractory patients who are inoperable and intolerant of radiotherapy is still extremely poor[1]. As a new form of regulated cell death, ferroptosis has come into the limelight, and numerous researchers have shown great interest in ferroptosis-mediated anti-tumour effects. A large number of studies have demonstrated that ferroptosis is involved in the regulation of molecular biological processes in tumours, including hepatocellular carcinoma, lung carcinoma, pancreatic carcinoma, and breast carcinoma[8]. Disulfidptosis as a novel mode of cell death, independent of existing programmed cell deaths such as apoptosis, ferroptosis, cuproptosis, etc., is caused by excessive disulfide formation in the actin cytoskeleton and the collapse of actin filaments, highlighting promising anticancer strategies for targeting disulfides[13]. In the present study, we constructed a prognostic model based on the Disulfidptosis-related ferroptosis gene based on the TCGA database and investigated the role of immune cell infiltration in the tumour microenvironment in the prognosis of STAD patients.
Differential analysis of gene rows between gastric cancer tissues and paracancerous tissues was performed by R software, and Univariate Cox analyses of the differential genes yielded DEGs that were associated with overall survival and prognosis, suggesting that Disulfidptosis-related ferroptosis genes play a potential regulatory role in the development of STAD. Based on the above intersection genes, a novel prognostic model integrating 7 genes (HNF4A, HELLS, SLC1A5, BID, DUSP1, TSC22D3 and AKR1C2) was firstly constructed. HNF4A (Hepatocyte Nuclear Factor 4 Alpha) is not only a core member and central regulator of glucose, fatty acid and lipid metabolism, but also has the ability to regulate the expression of multiple components within the three major regions of pontine, adherens junctions and tight junctions. Studies have shown that overexpression of HNF4A controls cell ferroptosis and enhances cellular proliferation, and may act as an oncogene to promote gastrointestinal adenocarcinoma development[14, 15]. HELLS (Helicase Eymphoid-Specific) is an ATP-dependent chromatin remodelling factor, which is mainly involved in the regulation of DNA methylation during cell proliferation. Relevant studies have shown that HELLS is involved in aerobic glycolysis in gastric cancer cells, and also exerts a cancer-promoting effect in a variety of tumours, such as pancreatic, colon and renal cancers[16, 17]. Glutamine transport mediated by SLC1A5 (Solute Carrier Family 1 Member 5) plays a key role in tumour cell metabolism, proliferation and ferroptosis, and is an up-regulated gene that is associated with ferroptosis in GC and correlates with patient prognosis, and correlates with tumour size, depth of tumour infiltration, lymph node metastasis and TNM staging[18–20]. Published articles have suggested that in clinical GC specimens not treated with chemotherapy or targeted agents, protein levels of DUSP1 (Dual Specificity Phosphatase-1) are significantly higher in paraneoplastic tissues than in cancerous tissues, and furthermore, increased expression of DUSP1 is associated with cancer progression, drug resistance and poor prognosis[21]. GILZ / TSC22D3 (Glucocorticoid-Induced Leucine Zipper) can either promote or inhibit tumour growth, depending on the type of tumour and its microenvironment. TSC22D3 plays a dual role in tumours: it not only promotes tumours by affecting the immune system and the tumour microenvironment, but also inhibits tumour growth by inducing apoptosis or inhibiting the proliferation of cancer cells[22]. There are fewer articles on the role of TSC22D3 in gastric cancer. The expression of AKR1C2 (Aldo-Keto Reductases Family 1 Member C2) has been associated with the prognosis of a variety of diseases including thyroid cancer, acute myeloid leukaemia (AML) and esophageal squamous cell carcinoma (ESCC)[23–25]. Some articles have now shown that the expression of AKR1C2 is associated with immunostimulants, immunosuppressants, chemokines and receptors, and that as a ferroptosis-related gene, the high expression of AKR1C2 correlates with a good prognosis in GC, which could potentially serve as a promising prognostic biomarker for GC patients[26]. The BID protein is a member of the Bcl-2 family that activates apoptosis and integrates both the two major apoptotic pathways connecting membranes (external) and mitochondria (internal). However, its role in cancer pathogenesis remains poorly elucidated, and it has also been suggested that BID expression lacks significant differences in different histopathological forms of cancer[27].
In this study, we showed that HNF4A, HELLS, SLC1A5, and BID, which were up-regulated in STAD expression, were negatively correlated with the level of infiltration of a variety of immune cells, and DUSP1, TSC22D3, and AKR1C2, which were down-regulated in STAD expression, were positively correlated with the level of infiltration of a variety of immune cells. In conclusion, the above results indicate that the seven disulfidptosis-related ferroptosis genes correlate with immune cell infiltration, suggesting that this prognostic model may influence the composition of the immune microenvironment of STAD, and become a potential target to inhibit STAD recurrence and metastasis, as well as a potential marker for differential diagnosis and evaluation of tumour biological properties. Continued advances in ICIs (Immune Check Point Inhibitors) therapy in recent years have deepened our understanding of the interactions between the immune system, cancer cells and the tumour microenvironment[28]. Currently tumour mutational load and immune checkpoint-associated gene expression do not accurately predict response to ICIs therapy. Therefore, the identification of biomarkers that can accurately predict the clinical efficacy of ICIs therapies is important to further advance precision immunotherapy[29, 30]. Among the many immunotherapeutic strategies, ICIs have shown great benefits in the treatment of a range of cancer types, for example the use of CTLA-4 and PD-1 or PD-L1 enhances anti-tumour immunity[31]. In this study, disulfidptosis-related ferroptosis genes were significantly associated with ICIs therapeutic target genes such as CD40LG, CD27, PDCD1LG2, CD28, CD86, and CD276. These findings suggest that the risk score model in this study has the potential to predict the efficacy of ICIs and will hopefully provide new perspectives for STAD treatment.
In this study, we identified the DGEs associated with disulfidptosis and ferroptosis in STAD by bioinformatics methods, and constructed a risk prediction model that can better classify STAD patients into high-risk and low-risk groups, which can provide clinicians with referable suggestions for evaluating the prognosis and the risk of recurrence of STAD patients, and provide a new way of thinking for designing the therapeutic strategies based on disulfidptosis and ferroptosis. However, there are some limitations in this study. The clinical information source of the prognostic model established in this paper is the TCGA database, and the stability of the model may be limited by factors such as ethnicity, geography, and sample size; in addition, the genes related to ferroptosis and disulfidptosis were obtained from the FerrDb database and from literature searches, and these genes may be continuously updated as the relevant studies of researchers from all walks of life continue to deepen. In addition, the genes related to ferroptosis and disulfidptosis were obtained from the FerrDb database and literature searches, and as researchers from all walks of life continue to deepen their studies, these genes may be updated continuously, so it is necessary to pay close attention to the development of the relevant frontiers and then adjust the design scheme; there is still room for exploring the biological mechanism of disulfidptosis and ferroptosis, and therefore, it is necessary to further experimental verification.