Comprehensive exploration of signal sequence receptor subunit 1 (SSR1) as a diagnostic and prognostic biomarker in liver hepatocellular carcinoma.

Am J Transl Res 2025;17(1):560-584 www.ajtr.org /ISSN:1943-8141/AJTR0158197 Original Article Comprehensive exploration of signal sequence receptor subunit 1 (SSR1) as a diagnostic and prognostic biomarker in liver hepatocellular carcinoma Bo Feng1*, Weixia Chen1*, Mingyue Sun1, Xijia Ma2, Jiarui Cao2, Zhenyu Zhang2, Chunzheng Ma1 Henan Province Hospital of TCM, Zhengzhou 450002, Henan, China; 2Henan University of Chinese Medicine, Zhengzhou 450046, Henan, China. *Equal contributors. 1 Received June 1, 2024; Accepted December 5, 2024; Epub January 15, 2025; Published January 30, 2025 Abstract: Objectives: This study investigated the expression, clinical relevance, and functional role of signal sequence receptor 1 (SSR1) in liver hepatocellular carcinoma (LIHC). SSR1’s potential as a diagnostic marker and its impact on tumor progression was assessed through multi-platform data analysis and in vitro functional assays. Methodology: Expression data from The Cancer Genome Atlas (TCGA), UALCAN, Oncomine, TIMER2.0, and Human Protein Atlas (HPA) were analyzed to assess SSR1 mRNA and protein expression in LIHC. Clinical correlations with tumor stage, race, gender, age, weight, and nodal metastasis were examined using UALCAN. Promoter methylation, mutation frequency, and prognostic significance were evaluated using UALCAN and OncoDB. Gene set enrichment analysis (GSEA) was conducted to identify pathways enriched in high SSR1 expression. Finally, real-time quantitative polymerase chain reaction (RT-qPCR), proliferation, colony formation, and wound healing assays were performed in QGY-7703 cell lines to validate the SSR1 function. Results: SSR1 was significantly upregulated in LIHC tissues across multiple databases. Promoter hypomethylation was identified as a potential mechanism for this upregulation. High SSR1 expression correlated with worse overall survival and advanced tumor stages. Functional assays revealed that SSR1, SSR2, and SSR3 knockdown in LIHC cells significantly reduced cell proliferation and colony formation while enhancing migratory capacity. Conclusion: SSR1 was overexpressed in LIHC and is associated with poor prognosis. It plays a critical role in promoting LIHC cell proliferation and survival, suggesting its potential as a diagnostic marker and therapeutic target. Keywords: LIHC, cancer, SSR1, prognosis, treatment Introduction Liver cancer is a major global health challenge, ranking as the sixth most common cancer and the third leading cause of cancer-related mortality worldwide [1, 2]. Hepatocellular carcinoma (HCC), also referred to as liver hepatocellular carcinoma (LIHC), accounts for the majority of liver cancer cases, making up approximately 75-85% of all diagnoses [3, 4]. The development of LIHC is closely linked to chronic liver diseases, such as hepatitis B virus (HBV) and hepatitis C virus (HCV) infections, excessive alcohol consumption, and non-alcoholic fatty liver disease (NAFLD), with liver cirrhosis often acting as a precursor [5, 6]. Despite advances in surgical and medical treatments, including liver transplantation, targeted therapies, and immunotherapies, the prognosis for LIHC patients remains poor, particularly in advanced stages [7, 8]. The five-year survival rate for patients diagnosed with late-stage LIHC is less than 20%, underscoring the urgent need for improved diagnostic, prognostic, and therapeutic strategies [9]. A key hurdle in improving LIHC outcomes is the lack of reliable biomarkers for early detection and therapeutic targeting [10]. Currently, available biomarkers, such as alpha-fetoprotein (AFP), have limited sensitivity and specificity, particularly in early-stage disease [11]. This has led to growing interest in identifying novel molecular targets that can be used to improve diagnostic precision and provide new avenues for therapeutic intervention [11]. Among the https://doi.org/10.62347/ANXV3598 SSR1 as a biomarker in LIHC Table 1. Clinical characteristics of LIHC patients (n = 374) Clinical Characteristics Gender Male Female Age ≤ 65 years > 60 years LIHC Stage Stage 1 Stage 2 Stage 3 Stage 4 Number of Patients Percentage (n = 374) (%) 253 121 67.6% 32.4% 177 196 47.3% 52.4% 173 87 85 5 46.3% 23.3% 22.7% 1.3% patterns of SSR1, its association with clinical outcomes, and its potential as a therapeutic target in LIHC. Our findings provide new insights into the role of SSR1 in liver cancer, highlighting its potential as a biomarker for diagnosis and prognosis, as well as a therapeutic target for intervention. By integrating bioinformatics data with experimental validation, this study contributes to the growing body of knowledge on the molecular underpinnings of LIHC and lays the groundwork for future research into SSR1 as a novel therapeutic avenue for liver cancer management. Methodology LIHC = Liver hepatocellular carcinoma. Data acquisition from The Cancer Genome Atlas (TCGA) database emerging molecular candidates, signal sequence receptor 1 (SSR1) has garnered attention for its involvement in protein translocation across the endoplasmic reticulum (ER) membrane, a process critical to maintaining cellular homeostasis [12, 13]. SSR1 is a subunit of the translocon-associated protein (TRAP) complex, which facilitates the movement of newly synthesized proteins into the ER for folding and post-translational modification [14]. Aberrant expression of SSR1 has been reported in several cancers, suggesting it may play a role in tumorigenesis and cancer progression. In breast cancer, SSR1 overexpression has been associated with worse clinical outcomes, including increased tumor size and higher metastatic potential [15]. Similarly, studies in lung and colorectal cancers have indicated that SSR1 contributes to cancer cell survival, proliferation, and metastasis, though the underlying mechanisms remain poorly understood [16, 17]. Gene expression data from LIHC studies were collected using the TCGA database (https:// cancergenome.nih.gov). Datasets included 50 normal and 374 tumor tissues (Table 1), with a workflow type of transcript per million (TPM). Despite its implications in other cancers, the role of SSR1 in LIHC has not been comprehensively studied. Given the importance of ER stress and protein homeostasis in cancer progression, SSR1 represents a promising candidate for further investigation in LIHC. In this study, we sought to elucidate the diagnostic, prognostic, and therapeutic relevance of SSR1 in LIHC through a combination of bioinformatic approaches and molecular experiments. Using publicly available cancer databases and in vitro analyses, we aimed to assess the expression 561 UALCAN, Oncomine, TIMER2.0 and Human Protein Atlas (HPA) databases UALCAN, Oncomine, TIMER2.0, and HPA are widely used bioinformatics platforms for cancer research. UALCAN (https://ualcan.path. uab.edu/) provides access to TCGA data, enabling researchers to analyze gene expression, promoter methylation, and survival rates across c (...truncated)