Long non-coding RNA KRT19P3 suppresses proliferation and metastasis through COPS7A-mediated NF-κB pathway in gastric cancer

Four centrosome-related genes to predict the prognosis and drug sensitivity of patients with colon cancer

BACKGROUND

As the primary microtubule organizing center in animal cells, centrosome abnormalities are involved in human colon cancer.

AIM

To explore the role of centrosome-related genes (CRGs) in colon cancer.

METHODS

CRGs were collected from public databases. Consensus clustering analysis was performed to separate the Cancer Genome Atlas cohort. Univariate Cox and least absolute shrinkage selection operator regression analyses were performed to identify candidate prognostic CRGs and construct a centrosome-related signature (CRS) to score colon cancer patients. A nomogram was developed to evaluate the CRS risk in colon cancer patients. An integrated bioinformatics analysis was conducted to explore the correlation between the CRS and tumor immune microenvironment and response to immunotherapy, chemotherapy, and targeted therapy. Single-cell transcriptome analysis was conducted to examine the immune cell landscape of core prognostic genes.

RESULTS

A total of 726 CRGs were collected from public databases. A CRS was constructed, which consisted of the following four genes: TSC1, AXIN2, COPS7A, and MTUS1. Colon cancer patients with a high-risk signature had poor survival. Patients with a high-risk signature exhibited decreased levels of plasma cells and activated memory CD4+ T cells. Regarding treatment response, patients with a high-risk signature were resistant to immunotherapy, chemotherapy, and targeted therapy. COPS7A expression was relatively high in endothelial cells and fibroblasts. MTUS1 expression was high in endothelial cells, fibroblasts, and malignant cells.

CONCLUSION

We constructed a centrosome-related prognostic signature that can accurately predict the prognosis of colon cancer patients, contributing to the development of individualized treatment for colon cancer.

COP9 signalosome complex is a prognostic biomarker and corresponds with immune infiltration in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is among the most common deadly tumors but still lacks specific biomarkers for diagnosis, prognosis, and treatment guidance. The COP9 signalosome (COPS) is an essential regulator of the ubiquitin conjugation pathway upregulated in various cancers. We evaluated the contributions of COPS subunits to HCC tumorigenesis and their utility for prognosis. We comprehensively evaluated the tumor expression pattern and tumorigenic functions of COPS subunits using The Cancer Genome Atlas (TCGA), The Human Protein Atlas and immunohistochemistry. Kaplan-Meier, Cox regression, ROC curve, and nomogram analyses were used to assess the predictive values of COPS subunits for clinical outcome. Expression levels of COPS subunits were significantly upregulated in HCC tissues, which predicted shorter overall survival (OS). Further, Cox regression analysis identified COPS5, COPS7B, and COPS9 as independent prognostic biomarkers for OS. High mutation rates were also found in COPS subunits. Functional network analysis indicated that COPS and neighboring genes regulate 'protein neddylation', 'protein deneddylation', and 'protein ubiquitination'. The COPS PPI included strong interactions with p53, CUL1/2/3/4, and JUN. Moreover, the correlations between COPS subunit expression levels and tumor immune cell infiltration rates were examined using TIMER, TISIDB, ssGSEA, and ESTIMATE packages. COPS subunits expression levels were positively correlated with specific tumor immune cell infiltration rates, immunoregulator expression levels, and microsatellite instability in HCC. Finally, knockout of COPS6 and COPS9 in HCC cells reduced while overexpression enhanced proliferation rate and metastasis capacity. Our study revealed that COPS potential biomarker for unfavorable HCC prognosis and indicators of immune infiltration, tumorigenicity, and metastasis.

LINC00355 promotes gastric carcinogenesis by scaffolding p300 to activate CDC42 transcription and enhancing HNRNPA2B1 to stabilize CDC42 mRNA dependent on m6A

LINC00355 is involved in the tumorigenesis of several types of cancer. We verified that LINC00355 is upregulated in gastric cancer (GC) and contributes to GC cells' proliferation and metastasis. RNA sequencing (RNA-seq) and rescue assays suggested that LINC00355 controls gastric carcinogenesis by regulating the expression of cell division cycle 42 (CDC42) guanosine triphosphatase (GTPases), thereby activating their downstream pathways. Most previous studies have shown that LINC00355 acts as a ceRNA by sponging miRNAs to modulate downstream gene expression. Our group focus on epigenetic regulatory potential of LINC00355 in gene expression. Mechanistically, LINC00355 binds to p300 histone acetyltransferase, specifying the histone modification pattern on the CDC42 promoter to activate CDC42 transcription, thereby altering GC cell biology. In addition, HNRNPA2B1, which is upregulated by LINC00355, recognizes the N6-methyladenosine (m6A) sites of CDC42 and enhances the stability of CDC42 mRNA transcripts. Therefore, LINC00355 is mechanistically, functionally, and clinically oncogenic in GC cells.

Investigation on the mechanism of the combination of eremias multiocellata and cisplatin in reducing chemoresistance of gastric cancer based on in vitro and in vivo experiments

BACKGROUND

Cisplatin (DDP) is one of the important chemotherapy drugs for patients with advanced gastric cancer and metastasis, but its resistance is a bottleneck problem that affects clinical efficacy and patient survival. Eremias multiocellata (EM) is a traditional Chinese herbal medicine, which has been used in the treatment of precancerous lesions, gastric cancer, liver fibrosis, and other digestive diseases. However, the mechanism of reducing chemotherapy resistance to gastric cancer is still unclear.

METHODS

We used the MTT assay to evaluate the proliferative viability of gastric cancer parental cell line MKN45 and its drug-resistant cell line MKN45/DDP, and compared their drug-resistance indices. The migration and invasion abilities of MKN45/DDP drug-resistant cells were evaluated using the Transwell assay. Apoptosis in MKN45/DDP drug-resistant cells was detected using flow cytometry. The effect of a combination of EM and cisplatin on the levels of reactive oxygen species (ROS) and lipid peroxides (LPO) in cisplatin-resistant gastric cancer cells was detected using ROS fluorescent probes and a lipid peroxidation assay kit in conjunction with flow cytometry. The effect of EM combined with cisplatin on the level of iron ions was detected by fluorescence probe and confocal laser technique. Hematoxylin-eosin staining (HE staining) was used to detect the histopathologic morphology of drug-resistant gastric cancer in nude mice. Ferroptosis-related proteins were measured using immunohistochemistry. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect tumor drug resistance-related genes. The NF-κB/Snail pathway-related proteins, PI3K/AKT/mTOR pathway-related proteins, and drug resistance-related proteins were detected by Western blot.

RESULTS AND CONCLUSIONS

The results of in vitro and in vivo experiments showed that EM combined with DDP could effectively inhibit the migration and invasive ability of MKN45/DDP cells, as well as induce apoptosis of MKN45/DDP cells; the combination of the two drugs could significantly increase the levels of ROS, lipid peroxidation and divalent ferric ions in MKN45/DDP cells, at the same time reducing the levels of Ferroptosis-related proteins, which could induce Ferroptosis. In addition, EM combined with DDP can also exert the effect of reversing DDP resistance and increasing the sensitivity of gastric cancer drug-resistant cells to DDP by regulating the NF-κB/Snail signaling pathway, PI3K/AKT/mTOR signaling pathway, and the expression of drug resistance-related proteins and genes.

Decoding the regulatory landscape of lncRNAs as potential diagnostic and prognostic biomarkers for gastric and colorectal cancers

Colorectal cancer (CRC) and gastric cancer (GC) are major contributors to cancer-related mortality worldwide. Despite advancements in understanding molecular mechanisms and improved drug treatments, the overall survival rate for patients remains unsatisfactory. Metastasis and drug resistance are major challenges contributing to the high mortality rate in both CRC and GC. Recent research has shed light on the role of long noncoding RNAs (lncRNAs) in the development and progression of these cancers. LncRNAs regulate gene expression through various mechanisms, including epigenetic modifications and interactions with microRNAs (miRNAs) and proteins. They can serve as miRNA precursors or pseudogenes, modulating gene expression at transcriptional and post-transcriptional levels. Additionally, circulating lncRNAs have emerged as non-invasive biomarkers for the diagnosis, prognosis, and prediction of drug therapy response in CRC and GC. This review explores the intricate relationship between lncRNAs and CRC/GC, encompassing their roles in cancer development, progression, and chemoresistance. Furthermore, it discusses the potential of lncRNAs as therapeutic targets in these malignancies. The interplay between lncRNAs, miRNAs, and tumor microenvironment is also highlighted, emphasizing their impact on the complexity of cancer biology. Understanding the regulatory landscape and molecular mechanisms governed by lncRNAs in CRC and GC is crucial for the development of effective diagnostic and prognostic biomarkers, as well as novel therapeutic strategies. This review provides a comprehensive overview of the current knowledge and paves the way for further exploration of lncRNAs as key players in the management of CRC and GC.

PIN1P1 is activated by CREB1 and promotes gastric cancer progression via interacting with YBX1 and upregulating PIN1

Long noncoding RNAs (lncRNAs) play critical roles in the carcinogenesis and progression of cancers. However, the role and mechanism of the pseudogene lncRNA PIN1P1 in gastric carcinoma remain unclear. The expression and effects of lncRNA PIN1P1 in gastric cancer were investigated. The transcriptional regulation of CREB1 on PIN1P1 was determined by ChIP and luciferase assays. The mechanistic model of PIN1P1 in gastric cancer was further explored by RNA pull-down, RIP and western blot analysis. PIN1P1 was overexpressed in gastric cancer tissues, and upregulated PIN1P1 predicted poor prognosis in patients. CREB1 was directly combined with the promoter region of PIN1P1 to promote the transcription of PIN1P1. CREB1-mediated enhanced proliferation, migration and invasion could be partially reversed by downregulation of PIN1P1. Overexpressed PIN1P1 promoted the proliferation, migration and invasion of gastric cancer cells, whereas decreased PIN1P1 showed the opposite effects. PIN1P1 directly interacted with YBX1 and promoted YBX1 protein expression, leading to upregulation of PIN1, in which E2F1 may be involved. Silencing of YBX1 during PIN1P1 overexpression could partially rescue PIN1 upregulation. PIN1, the parental gene of PIN1P1, was elevated in gastric cancer tissues, and its upregulation was correlated with poor patient outcomes. PIN1 facilitated gastric cancer cell proliferation, migration and invasion. To sum up, CREB1-activated PIN1P1 could promote gastric cancer progression through YBX1 and upregulating PIN1, suggesting that it is a potential target for gastric cancer.

Pathological roles of miRNAs and pseudogene-derived lncRNAs in human cancers, and their comparison as prognosis/diagnosis biomarkers

This review examines and compares the diagnostic and prognostic capabilities of miRNAs and lncRNAs derived from pseudogenes in cancer patients. Additionally, it delves into their roles in cancer pathogenesis. Both miRNAs and pseudogene-derived lncRNAs have undergone thorough investigation as remarkably sensitive and specific cancer biomarkers, offering significant potential for cancer detection and monitoring. . Extensive research is essential to gain a complete understanding of the precise roles these non-coding RNAs play in cancer, allowing the development of novel targeted therapies and biomarkers for improved cancer detection and treatment approaches.

Expression of selected long non-coding RNAs in gastric cancer cells treated with coumarin: Possible mechanisms for anti-cancer activity

Long non-coding RNAs (lncRNAs) can be utilized as prognostic indicators of gastric cancer since they can affect several cancer-related processes. Coumarin is a natural product with some useful anti-cancer properties. Here, we measured the expression of selected lncRNAs (RuPAR, SNHG6, CASC11, and their targets, miR-340-5p, p21, E-cadherin, and CDK1) in AGS gastric cancer cells treated with coumarin. MTT test has been utilized for assessing the AGS cells' cell viability after exposure to coumarin. The expression of the lncRNAs (RuPAR, SNHG6, and CASC11) and miR-340-5p was evaluated via qRT-PCR. Western blot analysis has been utilized to determine changes in p21, E-cadherin, and CDK1 expression. Coumarin decreased AGS viability in a dose-dependent manner. The coumarin treated cells had lower levels of the mRNAs known to be targets of lncRNAs SNHG6 and CASC11 compared to control. Additionally, the coumarin group had increased levels of lncRNA RuPAR expression when compared with the control group. Some lncRNA targets, including p21, E-cadherin, and CDK1, showed lower expression in the coumarin group compared to the control by Western blotting. Coumarin could be a promising pharmacological candidate to be included in gastric cancer treatment regimens because it modulates lncRNAs and their targets.

ETS-1-activated LINC01016 over-expression promotes tumor progression via suppression of RFFL-mediated DHX9 ubiquitination degradation in breast cancers

Long non-coding RNAs (lncRNAs) are key regulators during the development of breast cancer (BC) and thus may be viable treatment targets. In this study, we found that the expression of the long intergenic non-coding RNA 01016 (LINC01016) was significantly higher in BC tissue samples with positive lymph node metastasis. LINC01016, which is activated by the transcription factor ETS-1, contributes to the overt promotion of cell proliferation activity, enhanced cell migratory ability, S phase cell cycle arrest, and decreased apoptosis rate. By RNA pull-down assays and mass spectrometry analyses, we determined that LINC01016 competitively bound and stabilized DHX9 protein by preventing the E3 ubiquitin ligase RFFL from binding to DHX9, thereby inhibiting DHX9 proteasomal degradation. This ultimately led to an increase in intracellular DHX9 expression and activated PI3K/AKT signaling, with p-AKT, Bcl-2, and MMP-9 involvement. This is the first study to reveal that the LINC01016/DHX9/PI3K/AKT axis plays a critical role in the progression of BC, and thus, LINC01016 may serve as a potential therapeutic target for patients with BC.

Research Progress for Targeting Deubiquitinases in Gastric Cancers

Gastric cancers (GCs) are malignant tumors with a high incidence that threaten global public health. Despite advances in GC diagnosis and treatment, the prognosis remains poor. Therefore, the mechanisms underlying GC progression need to be identified to develop prognostic biomarkers and therapeutic targets. Ubiquitination, a post-translational modification that regulates the stability, activity, localization, and interactions of target proteins, can be reversed by deubiquitinases (DUBs), which can remove ubiquitin monomers or polymers from modified proteins. The dysfunction of DUBs has been closely linked to tumorigenesis in various cancer types, and targeting certain DUBs may provide a potential option for cancer therapy. Multiple DUBs have been demonstrated to function as oncogenes or tumor suppressors in GC. In this review, we summarize the DUBs involved in GC and their associated upstream regulation and downstream mechanisms and present the benefits of targeting DUBs for GC treatment, which could provide new insights for GC diagnosis and therapy.

Panels of mRNAs and miRNAs for decoding molecular mechanisms of Renal Cell Carcinoma (RCC) subtypes utilizing Artificial Intelligence approaches

Renal Cell Carcinoma (RCC) encompasses three histological subtypes, including clear cell RCC (KIRC), papillary RCC (KIRP), and chromophobe RCC (KICH) each of which has different clinical courses, genetic/epigenetic drivers, and therapeutic responses. This study aimed to identify the significant mRNAs and microRNA panels involved in the pathogenesis of RCC subtypes. The mRNA and microRNA transcripts profile were obtained from The Cancer Genome Atlas (TCGA), which were included 611 ccRCC patients, 321 pRCC patients, and 89 chRCC patients for mRNA data and 616 patients in the ccRCC subtype, 326 patients in the pRCC subtype, and 91 patients in the chRCC for miRNA data, respectively. To identify mRNAs and miRNAs, feature selection based on filter and graph algorithms was applied. Then, a deep model was used to classify the subtypes of the RCC. Finally, an association rule mining algorithm was used to disclose features with significant roles to trigger molecular mechanisms to cause RCC subtypes. Panels of 77 mRNAs and 73 miRNAs could discriminate the KIRC, KIRP, and KICH subtypes from each other with 92% (F1-score ≥ 0.9, AUC ≥ 0.89) and 95% accuracy (F1-score ≥ 0.93, AUC ≥ 0.95), respectively. The Association Rule Mining analysis could identify miR-28 (repeat count = 2642) and CSN7A (repeat count = 5794) along with the miR-125a (repeat count = 2591) and NMD3 (repeat count = 2306) with the highest repeat counts, in the KIRC and KIRP rules, respectively. This study found new panels of mRNAs and miRNAs to distinguish among RCC subtypes, which were able to provide new insights into the underlying responsible mechanisms for the initiation and progression of KIRC and KIRP. The proposed mRNA and miRNA panels have a high potential to be as biomarkers of RCC subtypes and should be examined in future clinical studies.

Identification of EMT-Related lncRNAs as Potential Prognostic Biomarkers and Therapeutic Targets for Pancreatic Adenocarcinoma

Epithelial-mesenchymal transition (EMT) can promote carcinoma progression by multiple mechanisms; many studies demonstrated the invasiveness of pancreatic adenocarcinoma (PAAD) associated with the EMT, but how it acts through an lncRNA-dependent manner is unknown. Here, we investigated 146 samples from The Cancer Genome Atlas (TCGA) and 92 samples from the International Cancer Genome Consortium (ICGC). By gene set variation analysis (GSVA) and weighted correlation network analysis (WGCNA), we explored the EMT-related long noncoding RNAs (EMTlnc). Then, we performed univariate Cox regression analysis to screen their prognostic value for PAAD. The least absolute contraction and selection operator (LASSO) Cox regression was used to establish EMT-related lncRNA prognostic signal (EMT-LPS). In addition, we established a competitive endogenous ceRNA network. Then, we identified 33 prognostic EMTlnc as prognostic lncRNAs and established an EMT-LPS which showed strong prognostic ability in stratification analysis. By corresponding risk scores, patients were divided into low-risk and high-risk subgroups. Principal component analysis (PCA) showed that these subgroups had individual EMT status. Enrichment analysis showed that in the high-risk subgroup, biological processes, pathways, and hallmarks related to malignant tumors are more common. What is more, we constructed a nomogram that had powerful ability to predict the overall survival rate (OS) of PAAD patients in two datasets. So, EMT-LPS are a principal element in PAAD's carcinoma progression and may help us in choosing the way of prognosis assessment and provide some clues to design the new drugs for PAAD.

USP15 in Cancer and Other Diseases: From Diverse Functionsto Therapeutic Targets

The process of protein ubiquitination and deubiquitination plays an important role in maintaining protein stability and regulating signal pathways, and protein homeostasis perturbations may induce a variety of diseases. The deubiquitination process removes ubiquitin molecules from the protein, which requires the participation of deubiquitinating enzymes (DUBs). Ubiquitin-specific protease 15 (USP15) is a DUB that participates in many biological cell processes and regulates tumorigenesis. A dislocation catalytic triplet was observed in the USP15 structure, a conformation not observed in other USPs, except USP7, which makes USP15 appear to be unique. USP15 has been reported to be involved in the regulation of various cancers and diseases, and the reported substrate functions of USP15 are conflicting, suggesting that USP15 may act as both an oncogene and a tumor suppressor in different contexts. The importance and complexity of USP15 in the pathological processes remains unclear. Therefore, we reviewed the diverse biological functions of USP15 in cancers and other diseases, suggesting the potential of USP15 as an attractive therapeutic target.

CircKDM4B suppresses breast cancer progression via the miR-675/NEDD4L axis

Increasing studies have indicated that circular RNAs (circRNAs) play pivotal roles in various cancers. Here, we aimed to explore the roles of circRNAs in breast cancer. We identified a novel circRNA circKDM4B (hsa_circ_0002926) by whole-transcriptome sequencing and validated this by Real-time quantitative polymerase chain reaction (RT-qPCR) and Sanger sequencing. It was significantly decreased in breast cancer tissues compared with adjacent non-tumor tissues. Furthermore, circKDM4B, which is mainly localized in the cytoplasm, was more resistant to actinomycin D or ribonuclease R than its linear transcript KDM4B. In addition, the overexpression of circKDM4B inhibited cell migration and invasion in vitro, while knockdown of circKDM4B induced the opposite effects. In vivo, circKDM4B suppressed tumor growth and metastasis. Additionally, circKDM4B inhibited migration and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro and angiogenesis in vivo. Mechanically, circKDM4B sponged miR-675 to upregulate the expression of NEDD4-like E3 ubiquitin protein ligase (NEDD4L), which catalyzes ubiquitination of PI3KCA, thereby inhibiting PI3K/AKT and VEGFA secretion. Collectively, these findings uncovered the tumor-suppressor role of circKDM4B in breast cancer, especially in angiogenesis and tumor metastasis, indicating that circKDM4B could be a potential therapeutic target for breast cancer progression.

LncRNA KRT19P3 Is Involved in Breast Cancer Cell Proliferation, Migration and Invasion

Long non-coding RNAs (LncRNAs) have already been taken as critical regulatory molecules in breast carcinoma (BC). Besides, the progression of BC is closely associated with the immune system. However, the relationship between lncRNAs and the tumor immune system in BC has not been fully studied. LncRNA KRT19P3 has been reported to inhibit the progression of gastric cancer. In the present study, we first discovered that KRT19P3 was downregulated in BC tissues compared with para cancer tissue. Then we showed that KRT19P3 could be used as a marker to differentiate BC from para cancer tissue. Increased expression of KRT19P3 markedly inhibited the proliferation, migration, and invasion rate of BC cells in vitro and tumor growth of BC in vivo. Conversely, KRT19P3 knockdown by siRNA markedly promoted the proliferation, migration, and invasion rate of BC cells after being transfected. Comparison of clinical parameters showed an inverse relationship between the expression of KRT19P3 and pathological grade. Furthermore, immunohistochemistry (IHC) was applied to reveal the positive rate of the expression of Ki-67, programmed death-ligand 1 (PD-L1), and CD8 in BC tissues. Correlation analysis showed that Ki-67 and PD-L1 were inversely proportional to KRT19P3 but CD8 was directly proportional to KRT19P3. In conclusion, this study demonstrated that lncRNA KRT19P3 inhibits BC progression, and may affect the expression of PD-L1 in BC, which in turn affects CD8⁺ T (CD8 positive Cytotoxic T lymphocyte) cells in the immune microenvironment.

Identification and Validation of a Potent Multi-lncRNA Molecular Model for Predicting Gastric Cancer Prognosis

Gastric cancer (GC) remains the third deadliest malignancy in China. Despite the current understanding that the long noncoding RNAs (lncRNAs) play a pivotal function in the growth and progression of cancer, their prognostic value in GC remains unclear. Therefore, we aimed to construct a polymolecular prediction model by employing a competing endogenous RNA (ceRNA) network signature obtained by integrated bioinformatics analysis to evaluate patient prognosis in GC. Overall, 1,464 mRNAs, 14,376 lncRNAs, and 73 microRNAs (miRNAs) were found to be differentially expressed in GC. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that these differentially expressed RNAs were mostly enriched in neuroactive ligand–receptor interaction, chemical carcinogenesis, epidermis development, and digestion, which were correlated with GC. A ceRNA network consisting of four lncRNAs, 21 miRNAs, and 12 mRNAs were constructed. We identified four lncRNAs (lnc00473, H19, AC079160.1, and AC093866.1) as prognostic biomarkers, and their levels were quantified by qRT-PCR in cancer and adjacent noncancerous tissue specimens. Univariable and multivariable Cox regression analyses suggested statistically significant differences in age, stage, radiotherapy, and risk score groups, which were independent predictors of prognosis. A risk prediction model was created to test whether lncRNAs could be used as an independent risk predictor of GC or not. These novel lncRNAs’ signature independently predicted overall survival in GC (p < 0.001). Taken together, this study identified a ceRNA and protein–protein interaction networks that significantly affect GC, which could be valuable for GC diagnosis and therapy.

UBQLN4 is activated by C/EBPβ and exerts oncogenic effects on colorectal cancer via the Wnt/β-catenin signaling pathway

Ubiquilin 4 (UBQLN4) is an important member of the ubiquitin-like protein family. An increasing number of studies have shown that UBQLN4 is an important regulator of tumorigenesis. Nevertheless, the biological function and detailed mechanisms of UBQLN4 in colorectal cancer (CRC) development and progression remain unclear. Here, we identified UBQLN4 upregulation in CRC tissues and it is positively associated with CRC size, TNM stage, and lymphatic metastasis. Patients with high UBQLN4 expression had a poor prognosis. Functionally, overexpression of UBQLN4 significantly promoted CRC cell proliferation, migration, and invasion, while UBQLN4 silencing elicited the opposite effect. This result was consistent with the conclusion that UBQLN4 expression correlated positively with the CRC size and lymphatic metastasis. In vivo, UBQLN4 silencing also inhibited tumor growth. Mechanistically, using gene set enrichment analysis (GSEA) and western blot experiments, we identified that UBQLN4 activated the Wnt/β-catenin signaling pathway to upregulate β-catenin and c-Myc expression, thereby promoting CRC proliferation, migration and invasion. A rescue experiment further verified this conclusion. Dual luciferase reporter, real-time quantitative PCR (RT-qPCR), western blot and chromatin immunoprecipitation (ChIP) assays indicated that the transcription factor CCAAT/enhancer-binding protein beta (C/EBPβ) directly bound to the UBQLN4 core promoter region and activated its transcription, upregulating β-catenin and c-Myc expression to promote CRC progression. Thus, our findings suggest that UBQLN4 is a key oncogene in CRC and may be a promising target for the diagnosis and treatment of patients with CRC.

Long non-coding RNAs: Biogenesis, functions, and clinical significance in gastric cancer

Gastric cancer (GC) is one of the most prevalent malignant tumor types and the third leading cause of cancer-related death worldwide. Its morbidity and mortality are very high due to a lack of understanding about its pathogenesis and the slow development of novel therapeutic strategies. Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs with a length of more than 200 nt. They play crucial roles in a wide spectrum of physiological and pathological processes by regulating the expression of genes involved in proliferation, differentiation, apoptosis, cell cycle, invasion, metastasis, DNA damage, and carcinogenesis. The aberrant expression of lncRNAs has been found in various cancer types. A growing amount of evidence demonstrates that lncRNAs are involved in many aspects of GC pathogenesis, including its occurrence, metastasis, and recurrence, indicating their potential role as novel biomarkers in the diagnosis, prognosis, and therapeutic targets of GC. This review systematically summarizes the biogenesis, biological properties, and functions of lncRNAs and highlights their critical role and clinical significance in GC. This information may contribute to the development of better diagnostics and treatments for GC.

The World of Pseudogenes: New Diagnostic and Therapeutic Targets in Cancers or Still Mystery Molecules?

Pseudogenes were once considered as “junk DNA”, due to loss of their functions as a result of the accumulation of mutations, such as frameshift and presence of premature stop-codons and relocation of genes to inactive heterochromatin regions of the genome. Pseudogenes are divided into two large groups, processed and unprocessed, according to their primary structure and origin. Only 10% of all pseudogenes are transcribed into RNAs and participate in the regulation of parental gene expression at both transcriptional and translational levels through senseRNA (sRNA) and antisense RNA (asRNA). In this review, about 150 pseudogenes in the different types of cancers were analyzed. Part of these pseudogenes seem to be useful in molecular diagnostics and can be detected in various types of biological material including tissue as well as biological fluids (liquid biopsy) using different detection methods. The number of pseudogenes, as well as their function in the human genome, is still unknown. However, thanks to the development of various technologies and bioinformatic tools, it was revealed so far that pseudogenes are involved in the development and progression of certain diseases, especially in cancer.

Autophagy and gastrointestinal cancers: the behind the scenes role of long non-coding RNAs in initiation, progression, and treatment resistance

Gastrointestinal (GI) cancers comprise a heterogeneous group of complex disorders that affect different organs, including esophagus, stomach, gallbladder, liver, biliary tract, pancreas, small intestine, colon, rectum, and anus. Recently, an explosion in nucleic acid-based technologies has led to the discovery of long non-coding RNAs (lncRNAs) that have been found to possess unique regulatory functions. This class of RNAs is >200 nucleotides in length, and is characterized by their lack of protein coding. LncRNAs exert regulatory effects in GI cancer development by affecting different functions such as the proliferation and metastasis of cancer cells, apoptosis, glycolysis and angiogenesis. Over the past few decades, considerable evidence has revealed the important role of autophagy in both GI cancer progression and suppression. In addition, recent studies have confirmed a significant correlation between lncRNAs and the regulation of autophagy. In this review, we summarize how lncRNAs play a behind the scenes role in the pathogenesis of GI cancers through regulation of autophagy.

Long noncoding RNAs: fine-tuners hidden in the cancer signaling network

With the development of sequencing technology, a large number of long non-coding RNAs (lncRNAs) have been identified in addition to coding genes. LncRNAs, originally considered as junk RNA, are dysregulated in various types of cancer. Although protein-coding signaling pathways underlie various biological activities, and abnormal signal transduction is a key trigger and indicator for tumorigenesis and cancer progression, lncRNAs are sparking keen interest due to their versatile roles in fine-tuning signaling pathways. We are just beginning to scratch the surface of lncRNAs. Therefore, despite the fact that lncRNAs drive malignant phenotypes from multiple perspectives, in this review, we focus on important signaling pathways modulated by lncRNAs in cancer to demonstrate an up-to-date understanding of this emerging field.

lncRNA LOC339524 inhibits the proliferation of bladder cancer cells by targeting the miR-875-5p/COPS7A signaling axis

It has been reported that long non-coding RNAs (lncRNAs) play a crucial role in the progression of various types of cancer. The role of numerous lncRNAs in a variety of cancer types has been investigated. However, the underlying mechanisms of the majority of lncRNAs in bladder cancer (BCa) remain to be elucidated. In the present study, abnormally expressed lncRNAs in BCa and para-carcinoma tissues were identified through screening the Cancer RNA-Seq Nexus database and were validated using reverse transcription-quantitative PCR. It was found that LOC339524 expression levels were markedly downregulated in BCa tissues and cells (J82, T24, UM-UC-3 and 5637). LOC339524 overexpression was revealed to suppress the proliferation of BCa cells. LOC339524 was also discovered to act as a sponge for microRNA (miR)-875-5p, as identified using dual luciferase reporter assays and biotin pull-down analysis. LOC339524 downregulated the expression of miR-875-5p and knockdown of miR-875-5p expression inhibited the proliferation of bladder cancer cells. In addition, COP9 signalosome subunit 7A (COPS7A) was identified to be the target gene of miR-875-5p and COPS7A expression level was upregulated following LOC339524 overexpression. lncRNA LOC339524 was proposed to function as a competitive endogenous RNA to facilitate the expression of COPS7A by binding to miR-875-5p. In conclusion, the findings of the present study suggested that LOC339524 may inhibit cell proliferation in BCa by targeting the miR-875-5p/COPS7A signaling axis.

LncRNA SLCO4A1-AS1 Accelerates Growth and Metastasis of Gastric Cancer via Regulation of the miR-149/XIAP Axis

OBJECTIVE

Recently, long noncoding RNA SLCO4A1 antisense RNA 1 (SLCO4A1-AS1) has been shown to act as an oncogene in several cancer types; however, its role in gastric cancer (GC) and its underlying molecular mechanisms are yet to be elucidated.

METHODS

Using the ENCORI database, we identified SLCO4A1-AS1, miR-149-5p (miR-149), and the X-linked inhibitor of apoptosis (XIAP) whose expressions were obviously changed in GC samples, and analyzed the correlation between their expressions in GC samples. Moreover, we explored the expression of SLCO4A1-AS1, miR-149, and XIAP in clinical samples and GC cell lines using RT-qPCR and western blotting assay; the correlation between them was analyzed using RNA immunoprecipitation and dual-luciferase reporter. CCK-8, colony formation, and Transwell assays were conducted to determine the effects of SLCO4A1-AS1, miR-149, and XIAP expression on cell proliferation, migration, and invasion, respectively. A nude mouse xenograft model was used to explore their function in xenograft growth.

RESULTS

SLCO4A1-AS1 was significantly upregulated in the GC samples and cell lines, and a high level of SLCO4A1-AS1 was associated with an advanced tumor stage and shortened patient survival. Mechanistically, SLCO4A1-AS1 post-transcriptionally regulated XIAP by functioning as competing endogenous RNA in GC to sponge miR-149. Further functional assays revealed that the overexpression of miR-149 and knockdown of XIAP considerably inhibited GC cell viability and its migratory and invasive characteristics in vitro. SLCO4A1-AS1 knockdown also determined the function of GC cells but was diminished by the miR-149 inhibitor in vitro. Finally, we demonstrated that the deletion of SLCO4A1-AS1 suppressed tumor growth and metastasis in vivo.

CONCLUSIONS

Altogether, these findings suggest that SLCO4A1-AS1 functions as a crucial oncogenic lncRNA in GC and it can facilitate GC tumor growth and metastasis by interacting with miR-149 and enhancing XIAP expression. Therefore, SLCO4A1-AS1 is a potential novel therapeutic target in GC treatment.

lncRNA DSCR8 mediates miR-137/Cdc42 to regulate gastric cancer cell proliferation, invasion, and cell cycle as a competitive endogenous RNA

lncRNA DSCR8 (Down syndrome critical region 8) is involved in progression of many cancers, but its specific role in gastric cancer (GC) is still unclear. Here, qRT-PCR detected upregulated expression of DSCR8 and Cdc42 and downregulated expression of miR-137 in GC. The protein expression level of Cdc42 in GC was upregulated as tested by western blot. Statistical analysis showed that DSCR8 was closely associated with some malignant clinicopathological features (such as tumor size, metastasis, and stage) in GC patients. Fluorescence in situ hybridization showed that DSCR8 was localized in the nucleus and cytoplasm. Dual-luciferase reporter gene, RNA immunoprecipitation, and biotin pull-down assays showed that DSCR8 could bind to miR-137 could bind to Cdc42. In vitro and in vivo assays showed that DSCR8 could promote proliferation, invasion, and the cycle of GC cells and inhibit cell apoptosis. In addition, a rescue experiment showed that DSCR8 regulated progression of GC cells via miR-137. Furthermore, DSCR8 regulated Cdc42 in GC cells by inhibiting miR-137. Taken together, these data indicated that DSCR8 could adsorb miR-137 to reduce its inhibitory effect on Cdc42 expression, thereby promoting the progression of GC cells and regulating the cell cycle. These results provide a novel direction for DSCR8 as a target of GC.

HPSE2 regulates malignant biological behavior of gastric cancer cells by inhibiting NF-κB and Wnt/β-catenin signaling pathways

BACKGROUND

With the improvement of medical level, remarkable progress has been made in the early diagnosis and treatment of gastric cancer, but the mortality of patients with gastric cancer is still high, and the prognosis is poor. Invasion and metastasis are important factors affecting the prognosis of patients. Therefore, it is of great significance to explore the pathogenesis of gastric cancer, inhibit the invasion and metastasis of gastric cancer cells, and improve the prognosis of patients. Heparanase (HPSE) is an endogenous endoglycosidase. Some studies have found that the expression level of HPSE in gastric cancer is significantly increased. However, the role of HPSE2 in gastric cancer is still unclear. This study aimed to investigate the role of HPSE2 in gastric cancer and the underlying mechanism.

AIM

To investigate whether HPSE regulates the malignant biological behavior of gastric cancer cells and explore the role of the nuclear factor-κB (NF-κB) and Wnt/β-Catenin signaling pathways in this process.

METHODS

From September 2019 to April 2021, 74 cases of gastric cancer tissues and adjacent normal tissues were collected, and the expression levels of HPSE2 in these tissues were determined. The human gastric cancer cell line MKN-28 was subcultured and transfected to obtain HPSE2 overexpressing cells. Cell proliferation, apoptosis, invasion, and migration were measured, and the expression levels of HPSE2, E-cadherin, N-cadherin, vimentin, transforming growth factor-β1 (TGF-β1), phosphorylated NF-κB p65 (p-NF-κB p65) and β-Catenin were measured.

RESULTS

Compared with the adjacent normal tissues, the expression level of HPSE2 in gastric cancer tissues was significantly lower (P < 0.01). Compared with control cells, the expression level of HPSE2 in HPSE2 overexpressing cells was significantly higher (P < 0.01). There was no significant difference in cell proliferation ability between the two groups on day 1 (P > 0.05); compared with the control group on day 2, the cell proliferation ability of the HPSE2 overexpression group was significantly decreased (P < 0.05 or P < 0.01). Compared with the control group, the apoptosis rate and the expression levels of Bax and E-cadherin in the HPSE2 overexpression group were significantly increased, while the invasion and migration abilities as well as the expression levels of Bax, Survivin, N-cadherin, vimentin, TGF-β1, p-NF-κB p65, and β-Catenin were significantly decreased (P < 0.01).

CONCLUSION

Up-regulation of HPSE2 expression can inhibit cell proliferation, invasion, and migration, suppress the epithelial-mesenchymal transition, and promote apoptosis, which may be achieved by inhibiting the NF-κB and Wnt/ β-catenin signaling pathways.

PTCSC3-mediated glycolysis suppresses thyroid cancer progression via interfering with PGK1 degradation

The Warburg effect (aerobic glycolysis), a hallmark of cancer, serves as a promising target for diagnosis and therapy. Growing evidence indicates that long non‐coding RNAs (lncRNAs) play an important role in aerobic glycolysis of various tumours. However, the correlation between lncRNAs and glycolysis in thyroid cancer cells is still poorly understood. In this study, we showed that lncRNA papillary thyroid cancer susceptibility candidate 3 (PTCSC3) was significantly downregulated in papillary thyroid carcinoma (PTC). Overexpression of PTCSC3 significantly inhibited the aerobic glycolysis and tumour growth of PTC cells. Consistently, PTCSC3 overexpression suppressed tumour progress in vivo. Mechanistically, PTCSC3 inhibits aerobic glycolysis and proliferation of PTC by directly interacting with PGK1, a key enzyme in glycolytic pathway. As a result, PTCSC3 performs its role in PTC development via PGK1 and may be a potential therapeutic target for PTC treatment.

Long non-coding RNAs regulated NF-κB signaling in cancer metastasis: Micromanaging by not so small non-coding RNAs

Cancer metastasis is a major reason for the cancer-associated deaths and a role of long non-coding RNAs (lncRNAs) in cancer metastasis is increasingly being realized. Among the many oncogenic pathways, NF-κB signalling's involvement in cancer metastasis as a key inflammation-regulatory transcription factor has been a subject of interest for long time. Accumulating data from in vitro as well as in vivo studies along with analysis of clinical cancer tissues points to regulation of NF-κB signalling by lncRNAs with implications toward the onset of cancer metastasis. LncRNAs FOXD2-AS1, KRT19P3 and the NF-κB interacting lncRNA (NKILA) associate with lymph node metastasis and poor prognosis of individual cancers. The role of epithelial-mesenchymal transition (EMT) in cancer metastasis is well known. EMT is regulated by NF-κB and regulation of NF-κB/EMT-induced metastasis by lncRNAs remains a hot topic of research with indications for such roles of lncRNAs MALAT1, SNHG15, CRNDE and AC007271.3. Among the many lncRNAs, NKILA stands out as the most investigated lncRNA for its regulation of NF-κB. This tumor suppressive lncRNA has been reported downregulated in clinical samples representing different human cancers. Mechanistically, NKILA has been consistently shown to inhibit NF-κB activation via inhibition of IκBα phosphorylation and the resulting suppression of EMT. NKILA is also a target of natural anticancer compounds. Given the importance of NF-κB as a master regulatory transcription factor, lncRNAs, as the modulators of NF-κB signaling, can provide alternate targets for metastatic cancers with constitutively active NF-κB.

Cascades between miRNAs, lncRNAs and the NF-κB signaling pathway in gastric cancer (Review)

Gastric cancer is a common digestive tract malignancy that is mainly treated with surgery combined with perioperative adjuvant chemoradiotherapy and biological targeted therapy. However, the diagnosis rate of early gastric cancer is low and both postoperative recurrence and distant metastasis are thorny problems. Therefore, it is essential to study the pathogenesis of gastric cancer and search for more effective means of treatment. The nuclear factor-κB (NF-κB) signaling pathway has an important role in the occurrence and development of gastric cancer and recent studies have revealed that microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are able to regulate this pathway through a variety of mechanisms. Understanding these interrelated molecular mechanisms is helpful in guiding improvements in gastric cancer treatment. In the present review, the functional associations between miRNAs, lncRNAs and the NF-κB signaling pathway in the occurrence, development and prognosis of gastric cancer were discussed. It was concluded that miRNAs and lncRNAs have complex relations with the NF-κB signaling pathway in gastric cancer. miRNAs/target genes/NF-κB/target proteins, signaling molecules/NF-κB/miRNAs/target genes, lncRNAs/miRNAs/NF-κB/genes or mRNAs, lncRNAs/target genes/NF-Κb/target proteins, and lncRNAs/NF-κB/target proteins cascades are all important factors in the occurrence and development of gastric cancer.

The novel role and function of LINC01235 in metastasis of gastric cancer cells by inducing epithelial-mesenchymal transition

LncRNAs play a vital role in the tumorigenesis of gastric cancer (GC). This study determined that LINC01235 expression has greater fold changes by analyzing TCGA RNA-Seq data. The qRT-PCR assay confirmed that LINC01235 is significantly over-expressed in GC cells and tissues. Additionally, the overall survival analysis showed that patients with a higher LINC01235 expression had a poorer prognosis than those with a lower LINC01235 expression. Univariate Cox regression analysis indicated that high LINC01235 expression is positively correlated with poor prognosis. Moreover, LINC01235 was an independent poor prognostic marker for GC in multivariate Cox analysis. Invitro assays suggested that LINC01235 knockdown suppresses GC cell migration and invasion. GSEA revealed that high LINC01235 expression is strongly enriched in the EMT pathway. Western blotting results revealed that LINC01235 silencing decreases the expression of EMT-induced proteins. In conclusion, LINC01235 can promote GC cell metastasis via EMT and function as a prognostic biomarker.

Identification and Construction of a Long Noncoding RNA Prognostic Risk Model for Stomach Adenocarcinoma Patients

Background

Long noncoding RNA-based prognostic biomarkers have demonstrated great potential in the diagnosis and prognosis of cancer patients. However, systematic assessment of a multiple lncRNA-composed prognostic risk model is lacking in stomach adenocarcinoma (STAD). This study is aimed at constructing a lncRNA-based prognostic risk model for STAD patients.

Methods

RNA sequencing data and clinical information of STAD patients were retrieved from The Cancer Genome Atlas (TCGA) database. Differentially expressed lncRNAs (DElncRNAs) were identified using the R software. Univariate and multivariate Cox regression analyses were performed to construct a prognostic risk model. The survival analysis, C-index, and receiver operating characteristic (ROC) curve were employed to assess the sensitivity and specificity of the model. The results were verified using the GEPIA online tool and our clinical samples. Pearson correlation coefficient analysis, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed to indicate the potential biological functions of the selected lncRNA.

Results

A total of 1917 DElncRNAs were identified from 343 cases of STAD tissues and 30 cases of noncancerous tissues. According to univariate and multivariable Cox regression analyses, four DElncRNAs (AC129507.1, LINC02407, AL022316.1, and AP000695.2) were selected to establish a prognostic risk model. There was a significant difference in the overall survival between high-risk patients and low-risk patients based on this risk model. The C-index of the model was 0.652. The area under the curve (AUC) for the ROC curve was 0.769. GEPIA results confirmed the expression and prognostic significance of AP000695.2 in STAD. Our clinical data confirmed that upregulated expression of AP000695.2 was correlated with the T stage, distant metastasis, and TNM stage in STAD. GO and KEGG analyses demonstrated that AP000695.2 was closely related to the tumorigenesis process.

Conclusions

In this study, we constructed a lncRNA-based prognostic risk model for STAD patients. Our study will provide novel insight into the diagnosis and prognosis of STAD patients.

Long Noncoding RNAs in the Metastasis of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) is a common malignant tumor worldwide. Metastasis is the main cause of the death of OSCC patients. Long noncoding RNAs (lncRNAs), one of the key factors affecting OSCC metastasis, are a subtype of RNA with a length of more than 200 nucleotides that has little or no coding potential. In recent years, the important role played by lncRNAs in biological processes, such as chromatin modification, transcription regulation, RNA stability regulation, and mRNA translation, has been gradually revealed. More and more studies have shown that lncRNAs can regulate the metastasis of various tumors including OSCC at epigenetic, transcriptional, and post-transcriptional levels. In this review, we mainly discussed the role and possible mechanisms of lncRNAs in OSCC metastasis. Most lncRNAs act as oncogenes and only a few lncRNAs have been shown to inhibit OSCC metastasis. Besides, we briefly introduced the research status of cancer-associated fibroblasts-related lncRNAs in OSCC metastasis. Finally, we discussed the research prospects of lncRNAs-mediated crosstalk between OSCC cells and the tumor microenvironment in OSCC metastasis, especially the potential research value of exosomes and lymphangiogenesis. In general, lncRNAs are expected to be used for screening, treatment, and prognosis monitoring of OSCC metastasis, but more work is still required to better understand the biological function of lncRNAs.

ASB16-AS1 up-regulated and phosphorylated TRIM37 to activate NF-κB pathway and promote proliferation, stemness, and cisplatin resistance of gastric cancer

BACKGROUND

Long non-coding RNA (lncRNA) ASB16 antisense RNA 1 (ASB16-AS1) is recognized as an oncogene in several cancer types, but its relation to GC is unknown. Tripartite motif containing 37 (TRIM37) has been proven to accelerate the development of gastric cancer (GC), whereas the molecular mechanism assisted ASB16-AS1 and TRIM37 in regulating GC progression remains unclear.

METHODS

Differentially expressed lncRNAs in GC samples were analyzed based on Gene Expression Omnibus (GEO) data. CCK-8 and colony formation assays were applied to determine the proliferative ability of GC cells. Stem cell-like phenotype of GC cells was assessed by sphere formation assay and flow cytometry analysis. Luciferase reporter assay, RNA immunoprecipitation (RIP), pulldown, and co-immunoprecipitation (Co-IP) were performed to verify the interplay of RNA molecules.

RESULTS

ASB16-AS1 was upregulated in GC samples according to GEO data and qRT-PCR analysis. ASB16-AS1 strengthened the proliferative ability and stem cell-like characteristics in GC cells. More importantly, ASB16-AS1 encouraged GC cell growth in vivo. Mechanistically, ASB16-AS1 strengthened TRIM37 expression by sequestering miR-3918 and miR-4676-3p. ASB16-AS1 activated NF-kappa B (NF-κB) pathway by cooperating with ATM serine/threonine kinase (ATM) to induce TRIM37 phosphorylation.

CONCLUSION

In summary, ASB16-AS1 exerted oncogenic functions in GC through modulating TRIM37 expression at both mRNA and protein levels.

Pseudogenes as Biomarkers and Therapeutic Targets in Human Cancers

Pseudogenes are commonly labeled as "junk DNA" given their perceived nonfunctional status. However, the advent of large-scale genomics projects prompted a revisit of pseudogene biology, highlighting their key functional and regulatory roles in numerous diseases, including cancers. Integrative analyses of cancer data have shown that pseudogenes can be transcribed and even translated, and that pseudogenic DNA, RNA, and proteins can interfere with the activity and function of key protein coding genes, acting as regulators of oncogenes and tumor suppressors. Capitalizing on the available clinical research, we are able to get an insight into the spread and variety of pseudogene biomarker and therapeutic potential. In this chapter, we describe pseudogenes that fulfill their role as diagnostic or prognostic biomarkers, both as unique elements and in collaboration with other genes or pseudogenes. We also report that the majority of prognostic pseudogenes are overexpressed and exert an oncogenic role in colorectal, liver, lung, and gastric cancers. Finally, we highlight a number of pseudogenes that can establish future therapeutic avenues.

The ELF3-regulated lncRNA UBE2CP3 is over-stabilized by RNA-RNA interactions and drives gastric cancer metastasis via miR-138-5p/ITGA2 axis

LncRNAs play essential roles in tumorigenesis and tumor progression. Pseudogene UBE2CP3 is an antisense intronic lncRNA. However, the biological function of UBE2CP3 in gastric cancer (GC) remains unknown. In this study, we revealed that lncRNA UBE2CP3 was aberrantly upregulated in multiple independent gastric cancer cohorts, and its overexpression was clinically associated with poor prognosis in GC. UBE2CP3 was mainly located in cytoplasm and promoted migratory and invasive capacities of GC cells in vitro and in vivo. Mechanismly, a novel dysregulated ceRNA network UB2CP3/miR-138-5p/ITGA2 was identified in GC by transcriptome sequencing. Furthermore, rescue assay further confirmed that UBE2CP3 mainly promoted GC progression through miR-138-5p/ITGA2 axis. More importantly, our data proved that UBE2CP3/IGFBP7 could form an RNA duplex, thereby directly interacting with the ILF3 protein. In turn, this RNA-RNA interaction between IGFBP7 mRNA and UBE2CP3 mediated by ILF3 protein plays an essential role in protecting the mRNA stability of UBE2CP3. In addition, transcription factor ELF3 was identified to be a direct repressor of lncRNA UBE2CP3 in GC. Taken together, overexpression of UBE2CP3 promotes tumor progression via cascade amplification of ITGA2 upregulation in GC. Our finding has revealed that the dysregulation of UBE2CP3 is probably due to the downregulation of ELF3 and/or the overexpression of IGFBP7 mRNA in GC. Our findings reveal, for the first time, that UBE2CP3 plays crucial a role in GC progression by modulating miR-138-5p/ITGA2 axis, suggesting that UBE2CP3 may serve as a potential therapeutic target in GC.

Pseudogene KRT17P3 drives cisplatin resistance of human NSCLC cells by modulating miR-497-5p/mTOR

Chemoresistance is a major obstacle in non–small cell lung cancer (NSCLC) treatment. The pseudogene keratin 17 pseudogene 3 (KRT17P3) has been previously shown to be upregulated in lung cancer tissues of patients with cisplatin resistance. In the present study, RT‐qPCR was performed to evaluate KRT17P3 levels in plasma samples collected from 30 cisplatin‐resistant and 32 cisplatin‐sensitive patients. We found that the plasma level of KRT17P3 is upregulated in cisplatin‐resistant patients, and the increased expression of plasma KRT17P3 is associated with poor chemotherapy response. Functional studies demonstrated that KRT17P3 overexpression in cultured NSCLC cells increases cell viability and decreases apoptosis upon cisplatin treatment in vitro and in vivo, while KRT17P3 knockdown has the opposite effect. Mechanistically, bioinformatics analysis, RNA immunoprecipitation, and dual luciferase reporter assay indicated that KRT17P3 acts as a molecular sponge for miR‐497‐5p and relieves the binding of miR‐497‐5p to its target gene mTOR. Rescue experiments validated the functional interaction between KRT17P3, miR‐497‐5p, and mTOR. Taken together, our findings indicate that KRT17P3/miR‐497‐5p/mTOR regulates the chemosensitivity of NSCLC, suggesting a potential therapeutic target for cisplatin‐resistant NSCLC patients. KRT17P3 may be a potential peripheral blood marker of NSCLC patients resistant to cisplatin.

LncRNA PCAT18/miR-301a/TP53INP1 axis is involved in gastric cancer cell viability, migration and invasion

MiR-301a is as an oncogene involved in the regulation of gastric cancer (GC) progression, but the underlying mechanism is unclear. This study was to explore the lncRNA PCAT18/miR-301a/TP53INP1 axis in regulating the GC cell proliferation and metastasis. In the present study, GC tissues and cell lines were collected for the detection of PCAT18 expression. Herein, we found that PCAT18 is significantly decreases in human GC tissues and five GC cell lines. Overexpression of PCAT18 inhibits cell viability, invasion and migration of GC cells and tumour growth of GC xenograft tumours. PCAT18 negatively regulates the expression level of miR-301a. The interaction between PCAT18 and miR-301a is confirmed by RIP and RNA pull down. MiR-301a mimic increases cell viability and promotes cell migration and invasion and reverses the inhibitory action of PCAT18. TP53INP1 expression is negatively regulated by miR-301a and TP53INP1/miR-301a is involved in GC viability, migration and invasion. The promoting of PCAT18 on TP53INP1 expression is abolished by miR-301a overexpression. In conclusion, lncRNA PCAT18 acts as a tumour suppressor for GC and lncRNA PCAT18, miR-301a and TP53INP1 comprise a signal axis in regulating GC cell proliferation, migration and invasion.

LncRNA-mediated posttranslational modifications and reprogramming of energy metabolism in cancer

Altered metabolism is a hallmark of cancer, and the reprogramming of energy metabolism has historically been considered a general phenomenon of tumors. It is well recognized that long noncoding RNAs (lncRNAs) regulate energy metabolism in cancer. However, lncRNA‐mediated posttranslational modifications and metabolic reprogramming are unclear at present. In this review, we summarized the current understanding of the interactions between the alterations in cancer‐associated energy metabolism and the lncRNA‐mediated posttranslational modifications of metabolic enzymes, transcription factors, and other proteins involved in metabolic pathways. In addition, we discuss the mechanisms through which these interactions contribute to tumor initiation and progression, and the key roles and clinical significance of functional lncRNAs. We believe that an in‐depth understanding of lncRNA‐mediated cancer metabolic reprogramming can help to identify cellular vulnerabilities that can be exploited for cancer diagnosis and therapy.

Epigenetic Mechanisms of LncRNAs Binding to Protein in Carcinogenesis

Simple Summary

The functional analysis of lncRNA, which has recently been investigated in various fields of biological research, is critical to understanding the delicate control of cells and the occurrence of diseases. The interaction between proteins and lncRNA, which has been found to be a major mechanism, has been reported to play an important role in cancer development and progress. This review thus organized the lncRNAs and related proteins involved in the cancer process, from carcinogenesis to metastasis and resistance to chemotherapy, to better understand cancer and to further develop new treatments for it. This will provide a new perspective on clinical cancer diagnosis, prognosis, and treatment.

Abstract

Epigenetic dysregulation is an important feature for cancer initiation and progression. Long non-coding RNAs (lncRNAs) are transcripts that stably present as RNA forms with no translated protein and have lengths larger than 200 nucleotides. LncRNA can epigenetically regulate either oncogenes or tumor suppressor genes. Nowadays, the combined research of lncRNA plus protein analysis is gaining more attention. LncRNA controls gene expression directly by binding to transcription factors of target genes and indirectly by complexing with other proteins to bind to target proteins and cause protein degradation, reduced protein stability, or interference with the binding of other proteins. Various studies have indicated that lncRNA contributes to cancer development by modulating genes epigenetically and studies have been done to determine which proteins are combined with lncRNA and contribute to cancer development. In this review, we look in depth at the epigenetic regulatory function of lncRNAs that are capable of complexing with other proteins in cancer development.

Long non‑coding RNA RP11‑400N13.3 promotes the progression of colorectal cancer by regulating the miR‑4722‑3p/P2RY8 axis

Accumulating evidence has shown that long non-coding RNAs (lncRNAs) play significant roles in the development and progression of many types of cancer including colorectal cancer. RP11-400N13.3 is a novel lncRNA discovered recently and its biological function and underlying mechanism in colorectal cancer remain elusive. This study aimed to reveal the relationship between RP11-400N13.3 and colorectal cancer. Our results demonstrated that the expression of RP11-400N13.3 was significantly upregulated in both colorectal cancer tissues and cell lines as compared to normal adjacent tissues and normal colonic epithelial cells by RT-qPCR, respectively. Upregulation of RP11-400N13.3 was found to be correlated with a poor overall survival rate. Functional studies revealed that RP11-400N13.3 facilitated the proliferation, migration, invasion and tumor growth of colorectal cancer cells while inhibiting the apoptosis of cancer cells in vitro and in vivo. We also observed that RP11-400N13.3 serves as a sponge for miR-4722-3p, and that P2Y receptor family member 8 (P2RY8) was predicted to be a target of miR-4722-3p by bioinformatics analysis. Western blot assay indicated that the expression of P2RY8 was negatively or positively regulated by miR-4722-3p or RP11-400N13.3. In addition, rescue experiments revealed that RP11-400N13.3 promoted proliferation, migration and invasion by directly regulating the expression of miR-4722-3p and P2RY8. In conclusion, our results revealed that RP11-400N13.3 promoted colorectal cancer progression via modulating the miR-4722-3p/P2RY8 axis, thus suggesting RP11-400N13.3 as a potential therapeutic target for the treatment of colorectal cancer.

RP11-480I12.5-004 Promotes Growth and Tumorigenesis of Breast Cancer by Relieving miR-29c-3p-Mediated AKT3 and CDK6 Degradation

Pseudogenes have been reported to exert oncogenic or tumor-suppressive functions in cancer. However, the expression, role, and mechanism of pseudogene-derived RNAs in breast cancer remain unclear. The RNA levels and prognostic values of pseudogenes in breast cancer were determined. The levels of RP11-480I12.5 in cell lines and clinical samples were validated by quantitative real-time PCR. In vitro effects of RP11-480I12.5 on cell growth were measured by cell counting kit-8 (CCK-8) assay, colony formation assay, cell counting assay, and flow cytometry analysis. Xenograft model was established to detect its in vivo effect. The potential mechanism of RP11-480I12.5 was also studied by a combination of bioinformatic analysis and experimental confirmation. Finally, the possible functional parental genes of RP11-480I12.5 in breast cancer were explored. After a series of bioinformatic analyses, RP11-480I12.5 was selected as the most potential pseudogene in breast cancer. RP11-480I12.5 expression was significantly upregulated in breast cancer cell lines and clinical breast cancer tissues. Knockdown of RP11-480I12.5 markedly suppressed cell proliferation and colony formation, induced cell apoptosis of breast cancer in vitro, and inhibited tumor growth in vivo. Four transcripts of RP11-480I12.5 (001/002/003/004) were identified. Only overexpression of RP11-480I12.5-004 significantly enhanced cell growth of breast cancer both in vitro and in vivo. RP11-480I12.5-004 mainly located in cytoplasm and increased AKT3 and CDK6 mRNA expression, at least in part, by competitively binding to miR-29c-3p. Six parental genes of RP11-480I12.5 were found, among which TUBA1B and TUBA1C were statistically linked to RP11-480I12.5 expression, possessed prognostic values, and were upregulated in breast cancer. Our findings suggested that pseudogene-derived long non-coding RNA (lncRNA) RP11-480I12.5-004 promoted growth and tumorigenesis of breast cancer via increasing AKT3 and CDK6 expression by competitively binding to miR-29c-3p.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

TMPO-AS1 promotes cell proliferation of thyroid cancer via sponging miR-498 to modulate TMPO

Background

Thyroid cancer (TC) is the most frequent endocrine malignancy. Long noncoding RNAs (lncRNAs) have been confirmed to act as significant roles in tumor development. The role of lncRNA TMPO-AS1 in TC is still unclear, so it remains to be explored. The aim of the research is to investigate the role and regulatory mechanism of TMPO-AS1 in TC.

Methods

TMPO-AS1 and TMPO expression in TC tumors and cells was detected by TCGA database and QRT-PCR assay respectively. CCK-8, EDU, TUNEL and western blot assays were conducted to identify the biological functions of TMPO-AS1 in TC. Luciferase reporter and RNA pull down assays were conducted to measure the interaction among TMPO-AS1, TMPO and miR-498.

Results

TMPO-AS1 was overexpressed in TC tissues and cell lines. Knockdown of TMPO-AS1 suppressed cell growth and accelerated cell apoptosis in TC. Furthermore, downregulation of TMPO-AS1 suppressed TMPO expression in TC. The data suggested that TMPO expression was upregulated in TC tissues and cell lines and was positively correlated with TMPO-AS1 expression in TC. Furthermore, the expression of miR-498 presented low expression in TC cells. And miR-498 expression was negatively regulated by TMPO-AS1, meanwhile, TMPO expression was negatively regulated by miR-498 in TC cells. Besides, it was confirmed that TMPO-AS1 could bind with miR-498 and TMPO in TC cells. In addition, it was validated that TMPO-AS1 elevated the levels of TMPO via sponging miR-498 in TC cells.

Conclusions

TMPO-AS1 promotes cell proliferation in TC via sponging miR-498 to modulate TMPO.

Long noncoding RNAs in gastric cancer: From molecular dissection to clinical application

Long noncoding RNAs (lncRNAs) are important regulators of cell processes that are usually dysregulated in gastric cancer (GC). Based on their high specificity and ease of detection in tissues and body fluids, increasing attention has spurred the study of the roles of lncRNAs in GC patients. Thus, it is necessary to elucidate the molecular mechanisms and further explore the clinical applications of lncRNAs in GC. In this review, we summarize current knowledge to examine dysregulated lncRNAs in GC and their underlying molecular mechanisms and activities in GC, which involve microRNA sponging, mRNA stability, genetic variants, alternative splicing, transcription factor binding, and epigenetic modification. More significantly, the potential of lncRNAs as prognostic, circulating, and drug-resistant biomarkers for GC is also described. This review highlights the method of dissecting molecular mechanisms to explore the clinical application of lncRNAs in GC. Overall, this review offers assistance in using lncRNAs as novel candidates for molecular mechanisms and for the identification of revolutionary biomarkers for GC.

Pseudogene-Derived lncRNAs and Their miRNA Sponging Mechanism in Human Cancer

Pseudogenes, abundant in the human genome, are traditionally considered as non-functional “junk genes.” However, recent studies have revealed that pseudogenes act as key regulators at DNA, RNA or protein level in diverse human disorders (including cancer), among which pseudogene-derived long non-coding RNA (lncRNA) transcripts are extensively investigated and has been reported to be frequently dysregulated in various types of human cancer. Growing evidence demonstrates that pseudogene-derived lncRNAs play important roles in cancer initiation and progression by serving as competing endogenous RNAs (ceRNAs) through competitively binding to shared microRNAs (miRNAs), thus affecting both their cognate genes and unrelated genes. Herein, we retrospect those current findings about expression, functions and potential ceRNA mechanisms of pseudogene-derived lncRNAs in human cancer, which may provide us with some crucial clues in developing potential targets for cancer therapy in the future.

WGCNA Co-Expression Network Analysis Reveals ILF3-AS1 Functions as a CeRNA to Regulate PTBP1 Expression by Sponging miR-29a in Gastric Cancer

Gastric cancer (GC) is one of the most common types of human cancers worldwide. However, the detail mechanisms underlying GC progression remained to be investigated. The present study identified 2823 differently expressed mRNAs and 441 differently expressed lncRNAs in GC. WGCNA was conducted to identify highly correlated lncRNAs and mRNAs. Bioinformatics analysis observed that these dysregulated lncRNAs were significantly associated with the regulation of angiogenesis, cell division, cell-cell adhesion, blood vessel development, adaptive immune response, gastric acid secretion, immune response. Co-expression analysis identified ILF3-AS1 was a key lncRNA involved in regulating GC progression. Loss of function assays showed that knockdown of ILF3-AS1 significantly suppressed GC cell proliferation and metastasis. Mechanically, the results indicate that ILF3-AS1 could enhance PTBP3 expression as an miR-29a sponge, thereby promoting the proliferation and metastasis of GC cells. Our work suggests that the ILF3-AS1/miR-29a/PTBP3 axis may be a potential target for the clinical diagnosis and treatment of GC.

MIR22HG As A Tumor Suppressive lncRNA In HCC: A Comprehensive Analysis Integrating RT-qPCR, mRNA-Seq, And Microarrays

Introduction

MIR22HG has a reported involvement in the tumorigenesis of a variety of cancers, including hepatocellular carcinoma (HCC). However, the exact molecular mechanism of MIR22HG in HCC has not been clarified.

Methods

In the present study, we integrated data from in-house RT-qPCR, RNA-sequencing, microarray, and literature studies to conduct a comprehensive evaluation of the clinico-pathological and prognostic significance of MIR22HG in an extremely large group of HCC samples. We also explored the potential mechanism of MIR22HG in HCC by analyzing the alteration profiles of MIR22HG in HCC to predict transcription factors (TFs) that may interact with MIR22HG and to annotate the biological functions of genes co-expressed with MIR22HG. MIR22HG expression was also compared in HCC nude mice xenografts before and after a treatment with nitidine chloride.

Results

We found that MIR22HG was downregulated in HCC and that this downregulation correlated with the malignant phenotype of HCC. Comprehensive analysis of the prognostic impact of MIR22HG in HCC revealed a beneficial effect of MIR22HG on the survival outcome of HCC patients. Seven cases of MIR22HG deep deletion occurred in 360 of the cancer genome atlas (TCGA) provisional HCC samples. A total of 22 MIR22HG-TF-mRNA triplets in HCC were predicted by the lncRNAmap. Co-expressed genes of MIR22HG, identified by weighted correlation network analysis (WGCNA), mainly participated in the pathways involving osteoclast differentiation, chemokine signaling pathways, and hematopoietic cell lineage. In vivo experiments demonstrated that nitidine chloride could stimulate MIR22HG expression in HCC xenografts.

Conclusion

In summary, MIR22HG may play a tumor-suppressive role in HCC by coordinating with predicted TFs and co-expressed genes, such as NLRP3, CSF1R, SIGLEC10, and ZEB2, or by being controlled by nitidine chloride.