Based on traditional treatments, increasingly novel technologies, such as targeted therapy, have improved the prognosis of cervical cancer patients to some extent. However, cervical cancer is still one of the most common gynecological cancers affecting women's health, necessitating ongoing research and the identification of new therapy options[15]. Cancer's pathophysiology is intimately linked to gene mutation and dysfunction. CircRNA affects gene transcription and regulation by interacting with miRNA, mRNA, or proteins via the ceRNA mechanism[16]. More evidence has emerged in recent years suggesting deregulation of circRNA expression plays a vital function in the ceRNA regulatory network and is a primary pathogenesis of malignancies such as colon cancer and bladder cancer[17–19]. However, there are few studies on the effect of circRNA on cervical cancer occurrence and prognosis.
To discover the hub genes that contribute to cervical cancer and to try to determine cervical cancer prognostic indicators, we used bioinformatics analysis to develop a circRNA-associated ceRNA regulatory network. Firstly, three data sets related to cervical cancer were downloaded from the GEO database, and their differential expressions were analyzed. CSCD and miRTarget were used to extract the regulatory connections between circRNA-miRNA and miRNA-mRNA. The ceRNA regulatory network was then built to examine the GO function and KEGG pathway of differentially expressed genes.
Using GO functional annotation, we discovered that the most enriched genes were involved in epidermis development, keratinocyte differentiation (BPs), and desmosome (CCs). These variables have been implicated in the pathogenesis of cervical cancer and other cancers in numerous studies. Through bioinformatics research, it was discovered that epidermal growth plays a role in the progression of cervical cancer before it is diagnosed[20, 21]. Cervical cancer and HPV-associated carcinogenesis may be aided by keratinocyte differentiation with additional transcription factors[22]. It has been found that desmosome can indirectly leads to the occurrence of malignant tumors through the upregulation of kazrin F[23]. The KEGG pathway analysis showed that the differently expressed genes were mainly enriched in complex and coagulation cascade, as well as staphylococcus aureus infection. A recent study discovered that one of the mechanisms leading to cervical cancer is the complex and coagulation cascade pathway, which is consistent with our findings[24]. According to Chen's research, staphylococcus aureus infection may elicit an inflammatory response that unwittingly increases HPV-induced malignant progression, increasing the chance of cervical cancer formation[25]. These studies further prove that the genes in our circRNA-associated ceRNA regulatory network may play an important role in the pathogenesis of the cervix.
Simultaneously, we used a circRNA-miRNA-mRNA regulatory network to predict the prognosis of cervical cancer patients. Finally, we hypothesized that the four mRNAs of EREG, HPOX, CDA, and SYNGR3 were strongly linked to cervical cancer prognosis. At the same time, we have verified the hub gene through qRT-PCR. Previous research has linked these mRNAs (excluding SYNGR3) to the occurrence and prognosis of a variety of cancers, including cervical cancer. The EREG (Epiregulin)-EGFR (epidermal growth factor receptor)-C-Myc pathway was identified as a critical axis driving the carcinogenesis of head and neck squamous cell carcinoma (HNSCC) in Liu's study, and EREG expression was suggested as a functional marker to predict HNSCC susceptibility to erlotinib treatment[26]. Other studies have discovered that EREG, as a cancer signature gene, is associated with cervical cancer malignant transformation, progression, and survival rate[27, 28]. Sebastian's team found that the EREG gene can reliably predict the prognosis of adenocarcinoma of the colon or rectum by selecting 331 patients from 472 participants with metastatic colorectal cancer[29]. HPOX deficiency can result in the loss of tumor suppressive activity and differentiation phenotype in human cells, suggesting that HPOX is both a major regulator of epigenetic dynamics and a critical determinant of differentiation[30]. According to recent studies, HOPX may also have a significant role in modulating differentiation phenotype and tumor suppressive activity, as well as altering prognosis via affecting downstream genes[31]. According to studies on pancreatic cancer, the CDA gene has been reported to cause persistent alterations in the endoplasmic reticulum, resulting in overexpression of the mucin 1 (MUC1) protein in cancer and promoting treatment resistance[32]. These miRNAs have been linked to a number of malignancies, including cervical cancer, according to our findings as well as previous studies. Therefore, we speculate that these four hub genes affecting prognosis may be indirectly linked through a certain protein pathway, thus jointly affecting the occurrence and prognosis of cervical cancer.
Previous studies have shown that mRNA may affect the proliferation of cervical cancer cells through immune infiltrating cells[33]. Zhao et al. demonstrated that the INHBA gene is a prognostic biomarker and correlated with immune cell infiltration in cervical cancer [34]. In our study, neutrophils were positively correlated with the EREG gene and the HOPX gene, but negatively correlated with the SYNGR3 gene, which is consistent with our previous analysis of prognosis. Therefore, we speculate that the hub gene may affect the pathophysiology and prognosis of cervical cancer through neutrophils.
The innovation of our study is that the results are based not only on the data obtained from the GEO database, but also on subsequent bioinformatics analysis (circRNA-associated ceRNA network), which also combines the source data of TCGA, including a large number of samples and detailed information related to prognosis. At the same time, our research also has some deficiencies. It lacks detailed data for long-term follow-up to check the mRNAs that predict prognosis. However, our research indirectly proves that these key RNAs may affect the progression of cervical carcinoma and provides a good foundation for further research.