LncRNA SNHG16 contributes to tumor progression via the miR-302b-3p/SLC2A4 axis in pancreatic adenocarcinoma

Molecular mechanisms underlying roles of long non-coding RNA small nucleolar RNA host gene 16 in digestive system cancers

This editorial reviews the molecular mechanisms underlying the roles of the long non-coding RNA (lncRNA) small nucleolar RNA host gene 16 (SNHG16) in digestive system cancers based on two recent studies on lncRNAs in digestive system tumors. The first study, by Zhao et al, explored how hBD-1 affects colon cancer, via the lncRNA TCONS_00014506, by inhibiting mTOR and promoting autophagy. The second one, by Li et al, identified the lncRNA prion protein testis specific (PRNT) as a factor in oxaliplatin resistance by sponging ZNF184 to regulate HIPK2 and influence colorectal cancer progression and chemoresistance, suggesting PRNT as a potential therapeutic target for colorectal cancer. Both of these two articles discuss the mechanisms by which lncRNAs contribute to the development and progression of digestive system cancers. As a recent research hotspot, SNHG16 is a typical lncRNA that has been extensively studied for its association with digestive system cancers. The prevailing hypothesis is that SNHG16 participates in the development and progression of digestive system tumors by acting as a competing endogenous RNA, interacting with other proteins, regulating various genes, and affecting downstream target molecules. This review systematically examines the recently reported biological functions, related molecular mechanisms, and potential clinical significance of SNHG16 in various digestive system cancers, and explores the relationship between SNHG16 and digestive system cancers. The findings suggest that SNHG16 may serve as a potential biomarker and therapeutic target for human digestive system cancers.

Roles of long non‑coding RNA SNHG16 in human digestive system cancer (Review)

The incidence of tumors in the human digestive system is relatively high, including esophageal cancer, liver cancer, pancreatic cancer, gastric cancer and colorectal cancer. These malignancies arise from a complex interplay of environmental and genetic factors. Among them, long non‑coding RNAs (lncRNAs), which cannot be translated into proteins, serve an important role in the development, progression, migration and prognosis of tumors. Small nucleolar RNA host gene 16 (SNHG16) is a typical lncRNA, and its relationship with digestive system tumors has been widely explored. The prevailing hypothesis suggests that the principal molecular mechanism of SNHG16 in digestive system tumors involves it functioning as a competitive endogenous RNA that interacts with other proteins, regulates various genes and influences a downstream target molecule. The present review summarizes recent research on the relationship between SNHG16 and numerous types of digestive system cancer, encompassing its biological functions, underlying mechanisms and potential clinical implications. Furthermore, it outlines the association between SNHG16 expression and pertinent risk factors, such as smoking, infection and diet. The present review indicated the promise of SNHG16 as a potential biomarker and therapeutic target in human digestive system cancer.

Expression of long noncoding RNA MEG3 and microRNA-302b-3p in colon cancer: Correlation with clinical stage and value in predicing prognosis after surgical treatment

BACKGROUND

More and more long non-coding RNAs and microRNAs have been found to have significant changes in expression levels during the occurrence and development of tumors, which can affect the expression of tumor suppressor genes or oncogenes and play an important role in the proliferation and metastasis of cancer cells.

AIM

To investigate the correlation between the expression of long non-coding RNA maternal imprinted gene 3 (LncRNA MEG3) and microRNA (miR)-302b-3p in colon cancer and clinical stage and analyze their value in predicting the prognosis after surgical treatment.

METHODS

A total of 97 patients with colon cancer treated at Jinhua Hospital of TCM from January 2017 to March 2022 were selected to compare the expression of LncRNA MEG3 and miR-302b-3p in different tissues, analyze the correlation between the expression of LncRNA MEG3 and miR-302b-3p and clinical pathological characteristics, compare the recurrence in patients with different LncRNA MEG3 and miR-302b-3p expression, analyze the factors affecting the recurrence of colon cancer after surgery, and analyze the impact of the interaction between LncRNA MEG3 and miR-302b-3p on the recurrence of colon cancer. The predictive value of LncRNA MEG3 and miR-302b-3p expression for the recurrence of colon cancer after surgery was evaluated.

RESULTS

The expression of LncRNA MEG3 and miR-302b-3p in colon cancer tissues was lower than that in tumor-adjacent tissues (P < 0.05). The expression of LncRNA MEG3 and miR-302b-3p in colon cancer tissues was not correlated with sex, age, or tumor size (P > 0.05), but was correlated with tumor differentiation, clinical stage, and lymph node metastasis (P < 0.05). In colon cancer tissues, the recurrence rate in patients with high LncRNA MEG3 and miR-302b-3p expression was lower than that of patients with lower LncRNA MEG3 and miR-302b-3p expression (P < 0.05). Tumor differentiation degree, clinical stage, and lymph node metastasis were all identified to be risk factors for colon cancer recurrence, and LncRNA MEG3 and miR-302b-3p expression were protective factors for colon cancer recurrence (P < 0.05). The interaction analysis showed that the synergistic effect of simultaneous exposure to LncRNA MEG3 and miR-302b-3p was 15.888 times greater than the effect of exposure to either LncRNA MEG3 or miR-302b-3p alone, and when simultaneously exposing to both, 56.98% of the risk of colon cancer recurrence was attributed to their synergistic effect. The area under the curve (AUC) (95% confidence interval [CI]) of LncRNA MEG3 and miR-302b-3p in predicting the prognosis of colon cancer patients was 0.720 (0.620-0.807) and 0.767 (0.670-0.847), respectively, and that of the combined prediction was 0.892 (0.813-0.946), with a sensitivity and specificity of 92.31% and 83.33%, respectively, which were significantly higher than those of either LncRNA MEG3 or miR-302b-3p alone.

CONCLUSION

The down-regulated expression of LncRNA MEG3 and miR-302b-3p in colon cancer is related to clinical stage. Clinical detection of their expression can be used to determine the malignant degree of tumor and predict the prognosis of surgical treatment, thus providing reference for adjustment of clinical treatment plan.

In vitro Anti-malignant Property of PCMT1 Silencing and Identification of the SNHG16/miR-195/PCMT1 Regulatory Axis in Breast Cancer Cells

BACKGROUND

Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) is a highly conserved protein repair enzyme that participates in regulating the progression of human cancers. We therefore studied the function and the related mechanisms of PCMT1 in breast cancer cells.

METHODS

Expression profile and prognostic analysis of PCMT1 in breast cancer patients were analyzed using online databases. PCMT1 expression in breast cancer cells was detected by western blot analysis. Cell proliferation was determined by CCK-8 and colony formation assays. Apoptosis was evaluated using flow cytometry analysis and caspase-3/7 activity assay. Cell invasion was assessed by Transwell invasion assay. The small nucleolar RNA host gene 16 (SNHG16)/miR-195/PCMT1 regulatory axis was identified using bioinformatics analysis.

RESULTS

PCMT1 expression was increased in breast cancer tissues and cells. High PCMT1 expression was correlated with poor prognosis in breast cancer patients. PCMT1 knockdown suppressed cell proliferation and colony formation ability in breast cancer cells. Moreover, PCMT1 knockdown induced apoptosis and restrained the invasive ability in breast cancer cells. PCMT1 overexpression increased the proliferative and invasive abilities of breast cancer cells. miR-195 was identified as the unique upstream miRNA of PCMT1. SNHG16 was identified as the unique upstream lncRNA of miR-195. SNHG16 knockdown downregulated PCMT1 by increasing miR-195 expression. Breast cancer cell proliferation was regulated by the SNHG16/miR-195/PCMT1 axis.

CONCLUSION

PCMT1 silencing inhibited cell proliferation and invasion and induced apoptosis in breast cancer cells and the SNHG16/miR-195/PCMT1 regulatory axis might serve as a potential therapeutic target for breast cancer.

Construction of a Prognostic Model Based on Cuproptosis-Related lncRNA Signatures in Pancreatic Cancer

Aim

The aim of this study is to identify cuproptosis-related lncRNAs and construct a prognostic model for pancreatic cancer patients for clinical use.

Methods

The expression profile of lncRNAs was downloaded from The Cancer Genome Atlas database, and cuproptosis-related lncRNAs were identified. The prognostic cuproptosis-related lncRNAs were obtained and used to establish and validate a prognostic risk score model in pancreatic cancer.

Results

In total, 181 cuproptosis-related lncRNAs were obtained. The prognostic risk score model was constructed based on five lncRNAs (AC025257.1, TRAM2-AS1, AC091057.1, LINC01963, and MALAT1). Patients were assigned to two groups according to the median risk score. Kaplan-Meier survival curves showed that the difference in the prognosis between the high- and low-risk groups was statistically significant. Multivariate Cox analysis showed that our risk score was an independent risk factor for pancreatic cancer patients. Receiver operator characteristic curves revealed that the cuproptosis-related lncRNA model can effectively predict the prognosis of pancreatic cancer. The principal component analysis showed a difference between the high- and low-risk groups intuitively. Functional enrichment analysis showed that different genes were involved in cancer-related pathways in patients in the high- and low-risk groups.

Conclusion

The risk model based on five prognostic cuproptosis-related lncRNAs can well predict the prognosis of pancreatic cancer patients. Cuproptosis-related lncRNAs could be potential biomarkers for pancreatic cancer diagnosis and treatment.

Long non-coding RNA SNHG16 decreased SMAD4 to induce gemcitabine resistance in pancreatic cancer via EZH2-mediated epigenetic modification

Gemcitabine resistance (GR) in pancreatic cancer (PC) results in poor patient outcomes. SMAD family member (Smad4) dysregulation is a significant role of GR in PC, and EZH2 is involved in Smad4 expression in tumor progression. Interestingly, lncRNA small nucleolar RNA host gene 16 (SNHG16) might interact with EZH2, indicating a potential pathway to overcome gemcitabine-resistant PC progression. We investigated the role of the SNHG16/EZH2/Smad4 pathway in gemcitabine-resistant PC cells (PANC-1/GR and SW1990/GR). First, we found that SNHG16 was upregulated both in wild-type PC cells and in gemcitabine-resistant PC cells. SNHG16 overexpression reduced gemcitabine cytotoxicity and apoptosis in PC cells. Meanwhile, SNHG16 upregulation caused p-Akt elevation and Smad4 reduction. However, SNHG16 silencing induced the opposite trend. Then, we found that EZH2 was enriched in SNHG16 based on RIP and RNA pulldown. In particular, SNHG16 overexpression promoted the interaction between EZH2 and the Smad4 promoter according to Chromatin immunoprecipitation-quantitative polymerase chain reaction. Finally, both EZH2 inhibition and Smad4 upregulation increased gemcitabine cytotoxicity and apoptosis in PC cells during SNHG16 overexpression. Moreover, both treatments decreased p-Akt and increased Smad4. Collectively, lncRNA SNHG16 decreased Smad4 to induce GR in PC via EZH2-mediated epigenetic modification.

Impact of Non-Coding RNAs on Chemotherapeutic Resistance in Oral Cancer

Drug resistance in oral cancer is one of the major problems in oral cancer therapy because therapeutic failure directly results in tumor recurrence and eventually in metastasis. Accumulating evidence has demonstrated the involvement of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), in processes related to the development of drug resistance. A number of studies have shown that ncRNAs modulate gene expression at the transcriptional or translational level and regulate biological processes, such as epithelial-to-mesenchymal transition, apoptosis, DNA repair and drug efflux, which are tightly associated with drug resistance acquisition in many types of cancer. Interestingly, these ncRNAs are commonly detected in extracellular vesicles (EVs) and are known to be delivered into surrounding cells. This intercellular communication via EVs is currently considered to be important for acquired drug resistance. Here, we review the recent advances in the study of drug resistance in oral cancer by mainly focusing on the function of ncRNAs, since an increasing number of studies have suggested that ncRNAs could be therapeutic targets as well as biomarkers for cancer diagnosis.

Long Noncoding Competing Endogenous RNA Networks in Pancreatic Cancer

Pancreatic cancer (PC) is a highly malignant disease characterized by insidious onset, rapid progress, and poor therapeutic effects. The molecular mechanisms associated with PC initiation and progression are largely insufficient, hampering the exploitation of novel diagnostic biomarkers and development of efficient therapeutic strategies. Emerging evidence recently reveals that noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs) and microRNAs (miRNAs), extensively participate in PC pathogenesis. Specifically, lncRNAs can function as competing endogenous RNAs (ceRNAs), competitively sequestering miRNAs, therefore modulating the expression levels of their downstream target genes. Such complex lncRNA/miRNA/mRNA networks, namely, ceRNA networks, play crucial roles in the biological processes of PC by regulating cell growth and survival, epithelial-mesenchymal transition and metastasis, cancer stem cell maintenance, metabolism, autophagy, chemoresistance, and angiogenesis. In this review, the emerging knowledge on the lncRNA-associated ceRNA networks involved in PC initiation and progression will be summarized, and the potentials of the competitive crosstalk as diagnostic, prognostic, and therapeutic targets will be comprehensively discussed.

A Review on the Role of Small Nucleolar RNA Host Gene 6 Long Non-coding RNAs in the Carcinogenic Processes

Being located on 17q25.1, small nucleolar RNA host gene 6 (SNHG16) is a member of SNHG family of long non-coding RNAs (lncRNA) with 4 exons and 13 splice variants. This lncRNA serves as a sponge for a variety of miRNAs, namely miR-520a-3p, miR-4500, miR-146a miR-16–5p, miR-98, let-7a-5p, hsa-miR-93, miR-17-5p, miR-186, miR-302a-3p, miR-605-3p, miR-140-5p, miR-195, let-7b-5p, miR-16, miR-340, miR-1301, miR-205, miR-488, miR-1285-3p, miR-146a-5p, and miR-124-3p. This lncRNA can affect activity of TGF-β1/SMAD5, mTOR, NF-κB, Wnt, RAS/RAF/MEK/ERK and PI3K/AKT pathways. Almost all studies have reported oncogenic effect of SNHG16 in diverse cell types. Here, we explain the results of studies about the oncogenic role of SNHG16 according to three distinct sets of evidence, i.e., in vitro, animal, and clinical evidence.

Low expression of lncRNA SBF2-AS1 regulates the miR-302b-3p/TGFBR2 axis, promoting metastasis in laryngeal cancer

The 5-year survival rate of laryngeal cancer continues to decline, and the laryngeal particularity of the anatomy adversely affects the patient's quality of life. Emerging evidence suggests that long noncoding RNAs (lncRNAs) are closely correlated to key steps in the malignant progression of cancer cells. In this study, we report the role of lncRNA SBF2-AS1/miR-302b-3p/TGFBR2 interactions in the metastasis of laryngeal squamous cell carcinoma (LSCC). We verified that SBF2-AS1 was significantly downregulated in LSCC tissues and cell lines using qRT-PCR analysis. Its low expression was correlated to lymph node metastasis and an advanced clinical stage. More importantly, LSCC patients with low expression of SBF2-AS1 tended to have a poor prognosis. Based on this, we performed gain-of-function and loss-of-function experiments in LSCC cell lines. The results confirmed that knocking down SBF2-AS1 can promote the metastasis of LSCC cells and enhance epithelial-mesenchymal transition phenotype, while the upregulation of SBF2-AS1 expression resulted in the opposite. Our in vivo model verified that SBF2-AS1 overexpression could inhibit LSCC cell metastasis. Subsequent mechanistic studies revealed that SBF2-AS1 acted as a competing endogenous RNA that upregulated the expression of TGFBR2 by endogenous sponging for miR-302b-3p in LSCC cell lines. Moreover, miR-302b-3p overexpression reversed the inhibitory effects on LSCC metastasis induced by upregulation of SBF2-AS1 expression, and inhibition of TGFBR2 expression reversed the effect of SBF2-AS1 on metastasis. Our study proposes SBF2-AS1 as a biomarker to predict the prognosis of LSCC patients and a novel potential therapeutic target.

Non-coding RNAs in pancreatic ductal adenocarcinoma: New approaches for better diagnosis and therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies with a 5-year survival rate less than 8%, which has remained unchanged over the last 50 years. Early detection is particularly difficult due to the lack of disease-specific symptoms and a reliable biomarker. Multimodality treatment including chemotherapy, radiotherapy (used sparingly) and surgery has become the standard of care for patients with PDAC. Carbohydrate antigen 19-9 (CA 19-9) is the most common diagnostic biomarker; however, it is not specific enough especially for asymptomatic patients. Non-coding RNAs are often deregulated in human malignancies and shown to be involved in cancer-related mechanisms such as cell growth, differentiation, and cell death. Several micro, long non-coding and circular RNAs have been reported to date which are involved in PDAC. Aim of this review is to discuss the roles and functions of non-coding RNAs in diagnosis and treatments of PDAC.