Overexpression of SNORA21 suppresses tumorgenesis of gallbladder cancer in vitro and in vivo

From Function to Mechanism: Unveiling the Role of Small Nucleolar Ribonucleic Acids in Digestive Tumours

Small nucleolar ribonucleic acids (snoRNAs) have emerged as crucial regulators in various biological processes and have garnered significant attention for their potential roles in cancer. These noncoding ribonucleic acids (RNAs) primarily guide ribosomal RNA (rRNA) pseudouridylation and 2'-O-methylation modifications and exhibit stable expression in the serum, making them promising biomarkers and therapeutic targets. Digestive tract cancer poses a severe global health threat due to its high mortality rate and difficulty in early detection. Understanding the molecular mechanisms underlying tumor development is critical for improving diagnostic and therapeutic strategies. Small nucleolar RNAs, with their diverse functions and stable presence in biological fluids, offer a unique opportunity to address these challenges. Small nucleolar RNAs are a class of small noncoding RNAs mainly located in the nucleolus of eukaryotic cells. They play essential roles in the maturation and modification of rRNAs, transfer RNAs, and small nuclear RNAs. They also participate in alternative splicing regulation and exhibit microRNA-like functions, influencing various cellular processes. Abnormal expression of snoRNAs has been closely linked to the development, invasion, and metastasis of digestive system tumors. Given their stable expression in serum and the ability to function independently of host genes, snoRNAs hold great potential as biomarkers for early screening, prognosis prediction, and therapeutic targets in digestive system tumors. Their involvement in key signaling pathways and molecular mechanisms provides a foundation for developing targeted therapies and improving patient outcomes. This review highlights the significance of snoRNAs in digestive system tumors, their biological roles, connections to cancer progression, and potential clinical applications. Further exploration of snoRNAs is expected to provide new insights into the diagnosis and treatment of digestive system tumors.

The diagnostic value of serum exosomal SNORD116 and SNORA21 for NSCLC patients

PURPOSE

Non-small cell lung cancer (NSCLC) is a widespread and serious global malignancy. This study aimed to examine the clinical relevance of serum exosomal SNORD116 and SNORA21 as novel diagnostic biomarkers for NSCLC.

METHODS

Serum exosomes from 226 healthy controls and 305 NSCLC patients were isolated by ultracentrifugation. Characterization of exosomes was conducted by qNano, transmission electron microscopy (TEM) and Western immunoblotting. RT-PCR revealed snoRNAs that were differentially expressed. Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance.

RESULTS

In NSCLC patients, the levels of serum exosomal SNORD116 and SNORA21 were significantly reduced compared to those in healthy controls (P < 0.0001 for both). ROC curves showed AUC values of 0.738 and 0.761. By combining SNORD116 and SNORA21 with traditional blood biomarkers CYFRA21-1 and carcinoembryonic antigen (CEA), the AUC increased to 0.917. Moreover, these two exosomal snoRNAs distinguished between patients with metastatic NSCLC (n = 132) and those with non-metastatic NSCLC (n = 173) significantly (P < 0.0001 for both). The ROC curves gave AUC values of 0.743 and 0.694, respectively. The combined analysis raised the AUC to 0.751. The diagnostic power of these two exosomal snoRNAs combined with CYFRA21-1 and CEA increased to 0.784.

CONCLUSION

This study demonstrated that serum exosomal SNORD116 and SNORA21 can be used as potential promising non-invasive diagnostic biomarkers for NSCLC.

SNORA71A Downregulation Enhances Gemcitabine Sensitivity in Gallbladder Cancer Cells by Inducing Ferroptosis Through Inhibiting the AKT/NRF2/GPX4 Pathway

Previous findings have indicated a marked upregulation of SNORA71A in gallbladder cancer (GBC) tissues compared to normal samples. However, the precise role and molecular mechanisms of SNORA71A in GBC remain largely unknown. Moreover, gemcitabine (GEM) drug resistance has been found to lead to unfavorable outcomes and recurrence in GBC patients. Therefore, this study aims to investigate the impact of SNORA71A on GBC and explore its potential effects on the sensitivity of GBC cells to GEM. RT-qPCR was conducted to assess SNORA71A level in matched normal and GBC tissues. Cell proliferation was examined through CCK-8 and 5-ethynyl-2'-deoxyuridine (EdU) assays. Additionally, the expression of proteins in GBC cells was analyzed using western blot assay. The level of SNORA71A was notably higher in GBC tissues relative to normal tissues. SNORA71A overexpression led to increased GBC cell proliferation and invasion. Conversely, SNORA71A deficiency strongly suppressed GBC cell proliferation and invasion and triggered cell apoptosis and ferroptosis. Additionally, downregulation of SNORA71A obviously enhanced the antiproliferative and anti-invasive effects of GEM on GBC cells, whereas these changes were reversed by inhibiting ferroptosis. Furthermore, deficiency of SNORA71A further augmented the GEM-induced downregulation of p-Akt, Nrf2, and GPX4 in NOZ cells; however, these effects were reversed by ferroptosis inhibition. Collectively, these findings suggested that downregulation of SNORA71A may increase the sensitivity of GBC cells to GEM by triggering ferroptosis through inhibiting the AKT/NRF2/GPX4 signaling pathway.

Advances in the mechanism of small nucleolar RNA and its role in DNA damage response

Small nucleolar RNAs (snoRNAs) were previously regarded as a class of functionally conserved housekeeping genes, primarily involved in the regulation of ribosome biogenesis by ribosomal RNA (rRNA) modification. However, some of them are involved in several biological processes via complex molecular mechanisms. DNA damage response (DDR) is a conserved mechanism for maintaining genomic stability to prevent the occurrence of various human diseases. It has recently been revealed that snoRNAs are involved in DDR at multiple levels, indicating their relevant theoretical and clinical significance in this field. The present review systematically addresses four main points, including the biosynthesis and classification of snoRNAs, the mechanisms through which snoRNAs regulate target molecules, snoRNAs in the process of DDR, and the significance of snoRNA in disease diagnosis and treatment. It focuses on the potential functions of snoRNAs in DDR to help in the discovery of the roles of snoRNAs in maintaining genome stability and pathological processes.

SNHG25 facilitates SNORA50C accumulation to stabilize HDAC1 in neuroblastoma cells

Increasing studies have pointed out that small nucleolar RNAs (snoRNAs) and their host genes (SNHGs) have multi-functional roles in cancer progression. Bioinformatics analysis revealed the importance of snoRNA host gene 25 (SNHG25) in neuroblastoma (NB). Hence, we further explored the function and molecular mechanism of SNHG25 in NB. Our study revealed that SNHG25 expression was upregulated in NB cells. Through loss-of-function assays, we discovered that silencing of SNHG25 suppressed NB cell proliferation, invasion, and migration. Moreover, we found that SNHG25 positively regulated snoRNA small nucleolar RNA, H/ACA box 50 C (SNORA50C) in NB cells, and SNORA50C depletion had the same function as SNHG25 silencing in NB cells. Moreover, we proved that SNHG25 recruited dyskerin pseudouridine synthase 1 (DKC1) to facilitate SNORA50C accumulation and associated small nucleolar ribonucleoprotein (snoRNP) assembly. In addition, it was manifested that SNHG25 relied on SNORA50C to inhibit ubiquitination of histone deacetylase 1 (HDAC1), thereby elevating HDAC1 expression in NB cells. Further, HDAC1 was proven to be a tumor-facilitator in NB, and SNORA50C contributed to NB cell growth and migration through the HDAC1-mediated pathway. In vivo xenograft experiments further supported that SNHG25 promoted NB progression through SNORA50C/HDAC1 pathway. Our study might provide a novel sight for NB treatment.

Reiterating the Emergence of Noncoding RNAs as Regulators of the Critical Hallmarks of Gall Bladder Cancer

Gall bladder cancer (GBC) is a rare and one of the most aggressive types of malignancies, often associated with a poor prognosis and survival. It is a highly metastatic cancer and is often not diagnosed at the initial stages, which contributes to a poor survival rate of patients. The poor diagnosis and chemoresistance associated with the disease limit the scope of the currently available surgical and nonsurgical treatment modalities. Thus, there is a need to explore novel therapeutic targets and biomarkers that will help relieve the severity of the disease and lead to advanced therapeutic strategies. Accumulating evidence has correlated the atypical expression of various noncoding RNAs (ncRNAs), including circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and small nucleolar RNAs (snoRNA) with the increased cell proliferation, epithelial-mesenchymal transition (EMT), invasion, migration, metastasis, chemoresistance, and decreased apoptosis in GBC. Numerous reports have indicated that the dysregulated expression of ncRNAs is associated with poor prognosis and lower disease-free and overall survival in GBC patients. These reports suggest that ncRNAs might be considered novel diagnostic and prognostic markers for the management of GBC. The present review recapitulates the association of various ncRNAs in the initiation and progression of GBC and the development of novel therapeutic strategies by exploring their functional and regulatory role.

Identification of UBE2T as an independent prognostic biomarker for gallbladder cancer

Gallbladder cancer is the most common biliary tract malignant tumor, with unfavorable patient outcomes. The present study aimed to identify potential diagnostic or prognostic biomarkers for gallbladder cancer. To do so, differentially expressed genes in the gallbladder walls and tumor tissues of patients with gallbladder cancer were analyzed via microarray. Furthermore, a protein-protein interaction network was constructed and genes with a degree score >10 were selected as hub genes. As ubiquitin conjugating enzyme E2T (UBE2T) was considered to be a hub gene, its expression was assessed via reverse transcription-quantitative (RT-q)PCR and immunohistochemistry (IHC). In addition, the association between UBE2T expression and the clinicopathological characteristics of patients with gallbladder cancer was analyzed using the χ² test. Furthermore, all patients were divided into high- and low groups based on UBE2T expression level and overall survival analysis was performed. Univariate and multivariate Cox regression analyses were performed to determine whether UBE2T may serve as an independent risk factor for gallbladder cancer. The results demonstrated that UBE2T expression was upregulated in the gallbladder walls and tumor tissues of patients with gallbladder cancer. Furthermore, UBE2T expression level was confirmed to be upregulated following RT-qPCR, and results from IHC demonstrated that UBE2T was predominantly expressed in the cytoplasm of gallbladder cancer cells. In addition, high UBE2T expression level was associated with clinical stage, T classification, N classification and M classification. The results from Univariate and multivariate analyses indicated that UBE2T expression level may be considered as an independent risk factor for gallbladder cancer. Taken together, the findings from this study suggested that high UBE2T expression level may contribute to the poor prognosis of patients with gallbladder cancer, and that UBE2T may act as an independent prognostic biomarker for these patients.