Long non-coding RNA SNHG1 predicts a poor prognosis and promotes colon cancer tumorigenesis

ncRNAs-mediated overexpression of STIL predict unfavorable prognosis and correlated with the efficacy of immunotherapy of hepatocellular carcinoma

BACKGROUND

STIL centriolar assembly protein (STIL) is a cytoplasmic protein implicated in cellular growth and proliferation as well as chromosomal stability, which abnormal condition affected tumor immunity and tumor progression. However, the role of STIL in the biological mechanism of hepatocellular carcinoma (HCC) remains unclear.

METHODS

Comprehensive bioinformatic approaches, in vitro functional assays, and validation were conducted to elucidate the oncogenic value of STIL in HCC.

RESULTS

In the present study, we found that STIL may serve as an independent prognostic indicator and a potential oncogene in HCC. Gene set enrichment analysis (GSEA), and Gene set variation analysis (GSVA) showed that upregulated expression of STIL was positively associated with pathways enriched in the cell cycle and DNA damage response. Subsequently, we identified several non-coding RNAs (ncRNAs) accounting for the upregulation of STIL expression using a combination of in silico bioinformatics approaches (including expression analysis, correlation analysis, and survival analysis). Finally, CCNT2-AS1/SNHG1-has-miR-204-5p-STIL axis was screened out as the most potential upstream ncRNA-related pathway of STIL in HCC. Moreover, STIL expression is highly associated with the infiltration of immune cells, the expression of immune checkpoints, as well as the survival benefit of immunotherapy/chemotherapy.

CONCLUSIONS

Our study discloses that ncRNAs-mediated overexpression of STIL independently predicted poor prognosis and correlated with the efficacy of PD-1-targeted immunotherapy in HCC.

Analysis of PANoptosis-Related LncRNA-miRNA-mRNA Network Reveals LncRNA SNHG7 Involved in Chemo-Resistance in Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is one of the most common malignancies, and its metastatic lesions are the leading cause of death in COAD patients. PANoptosis is a recently identified pathway for programmed cell death implicated in developing COAD. Long non-coding RNAs (lncRNAs) are key regulators of cancer occurrence and progress. Although their function has captured much attention in COAD, the relationship between COAD metastasis-associated lncRNA expression and PANoptosis remains elusive. Therefore, this study aimed to explore the potential regulatory roles of metastasis- and PANoptosis-associated lncRNAs in COAD. Nine lncRNAs associated with metastasis and PANoptosis in COAD were identified from The Cancer Genome Atlas (TCGA) and GEO databases. Their functions were analyzed by multiple bioinformatics methods, and the lncRNA-miRNA-mRNA network was constructed. Multivariate Cox analysis identified one lncRNA (SNHG7) significantly related to COAD prognosis. Subsequent analyses showed its expression correlated with tumor stage and lymph node metastasis. Moreover, drug sensitivity analysis and in vitro experiments suggest that lncRNA SNHG7 contributes to drug resistance in COAD. In summary, lncRNA SNHG7 is a potential target for diagnosing and treating COAD and plays a crucial role in regulating apoptosis, metastasis, and drug resistance in COAD.

The Long Non-Coding RNA FAM222A-AS1 Negatively Modulates MiR-Let-7f to Promote Colorectal Cancer Progression

Accumulating evidence indicates that lncRNAs are potential biomarkers and key regulators of tumor development and progression. The present study aimed to screen abnormal expression lncRNAs and investigate the mechanisms underlying the function in the progression of colorectal cancer (CRC). Potential CRC prognosis-associated dysregulated lncRNAs were screened and identified using bioinformatics analysis. Loss/gain-of-function experiments were performed to detect the biological roles of FAM222A-AS1 in CRC cell phenotypes in vitro and in vivo. The potential microRNAs that interact with FAM222A-AS1 were identified using online tools and were verified using qRT-PCR and luciferase reporter assay. The expression of FAM222A-AS1 is significantly upregulated in CRC tumor samples and cell lines. CRC patients with elevated FAM222A-AS1 expression in the tumor samples had unfavorable overall survival and disease-free survival. Silencing FAM222A-AS1 expression significantly inhibited CRC cell proliferation, migration, and invasion both in vitro and in vivo. Furthermore, FAM222A-AS1 was mainly distributed in the cytoplasm. It may directly bound to miR-let-7f and inhibit its expression and upregulate MYH9. In summary, FAM222A-AS1, as a novel oncogene in CRC, may promote the CRC progression by inhibiting miR-let-7f/MYH9 axis. The FAM222A-AS1/miR-let-7f/MYH9 signaling pathway may be a novel valuable target for inhibiting CRC.

An Overview of Long Non-Coding (lnc)RNAs in Neuroblastoma

Neuroblastoma (NB) is a heterogeneous developmental tumor occurring in childhood, which arises from the embryonic sympathoadrenal cells of the neural crest. Although the recent progress that has been done on this tumor, the mechanisms involved in NB are still partially unknown. Despite some genetic aberrations having been identified, the sporadic cases represent the majority. Due to its wide heterogeneity in clinical behavior and etiology, NB represents a challenge in terms of prevention and treatment. Since a definitive therapy is lacking so far, there is an urgent necessity to unveil the molecular mechanisms behind NB onset and progression to develop new therapeutic approaches. Long non-coding RNAs (lncRNAs) are a group of RNAs longer than 200 nucleotides. Whether lncRNAs are destined to become a protein or not, they exert multiple biological functions such as regulating gene expression and functions. In recent decades, different research has highlighted the possible role of lncRNAs in the pathogenesis of many diseases, including cancer. Moreover, lncRNAs may represent potential markers or targets for diagnosis and treatment of diseases. This mini-review aimed to briefly summarize the most recent findings on the involvement of some lncRNAs in NB disease by focusing on their mechanisms of action and possible role in unveiling NB onset and progression.

Analysis of the regulation of metastasis-associated lung adenocarcinoma transcript 1 on the biological behavior of breast cancer

BACKGROUND

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a class of long non-coding RNA (lncRNA) that has been proved to be closely related to many cancers.

METHODS

The relevant research on MALAT1 in cancers published in recent years were collected and integrated. CiteSpace was employed to draw a knowledge map of MALAT1 in breast cancer, to evaluate the research front-burner issues. Then, multiple microarray data sets were searched from online data for meta-analysis to evaluate the relationship between MALAT1 and breast cancer survival rate.

RESULTS

The results showed that MALAT1 had been widely studied in the proliferation and differentiation of cancer cells, and MALAT1 might regulate breast cancer through the PI3K/AKT/mTOR signaling pathway. In addition, high expression of MALAT1 had a significant correlation with relapse-free survival (HR: 1.51, 95% CI: 0.79-2.29), while there was no significant correlation between MALAT1 expression and overall survival (HR: 1.09, 95% CI: 0.63-1.72).

CONCLUSIONS

The expression level of lncRNA MALAT1 was closely related to cancer progression and prognosis of cancer patients. Moreover, the expression of MALAT1 was strongly associated with the survival rate of recurrence-free breast cancer. However, since the present study only adopted the existing literature for visual analysis, subsequent experiments are needed to be done to verify this conclusion. It is hoped that this work could provide a theoretical foundation for promoting the clinical adoption of MALAT1 in the prediction, diagnosis, and treatment of breast cancer, and point out a new direction for the in-depth exploration of the function of MALAT1.

Overexpression of LncRNA SNHG1 Were Suitable for Oncolytic Adenoviruse H101 Therapy in Oral Squamous-Cell Carcinoma

Background

As the most prevalent type of head and neck cancer, oral squamous-cell carcinoma (OSCC) accounts for nearly 90% of all oral cancer cases. Despite great progress having been made in the diagnosis and treatment of OSCC recently, the survival rate of OSCC patients has not risen remarkably. Chemotherapy is commonly used for OSCC treatment; however, the emergence of chemoresistance limits its long-term curative effect. Therefore, identifying effective biomarkers and molecular mechanisms is essential to the development of therapeutic strategies for OSCC.

Methods

qRT-PCR assays were performed to detect SNHG1 expression in OSCC tissue and cells, and CCK8 assays and animal experiments used to examine cell proliferation. In addition, CCK8 assays were used to detect IC₅₀ values of cisplatin, 5Fu, Dox, and oncolytic adenovirus H101.

Results

We found that SNHG1 was overexpressed in OSCC tissue and cells and was associated with OSCC progression. In addition, knockdown of SNHG1 suppressed cell proliferation in vitro and in vivo. Importantly, we found that oncolytic adenovirus H101 showed better antitumor effects in OSCC with high SNHG1 expression, and chemotherapy showed worse anti-tumor effects in OSCC with high SNHG1 expression.

Conclusion

SNHG1 can act as a diagnostic biomarker for OSCC, and may be a biomarker for treatment options.

Long noncoding RNAs: functions and mechanisms in colon cancer

Evidence indicates that long non-coding RNAs (lncRNAs) play a crucial role in the carcinogenesis and progression of a wide variety of human malignancies including colon cancer. In this review, we describe the functions and mechanisms of lncRNAs involved in colon oncogenesis, such as HOTAIR, PVT1, H19, MALAT1, SNHG1, SNHG7, SNHG15, TUG1, XIST, ROR and ZEB1-AS1. We summarize the roles of lncRNAs in regulating cell proliferation, cell apoptotic death, the cell cycle, cell migrative and invasive ability, epithelial-mesenchymal transition (EMT), cancer stem cells and drug resistance in colon cancer. In addition, we briefly highlight the functions of circRNAs in colon tumorigenesis and progression, including circPPP1R12A, circPIP5K1A, circCTIC1, circ_0001313, circRNA_104916 and circRNA-ACAP2. This review provides the rationale for anticancer therapy via modulation of lncRNAs and circular RNAs (circRNAs) in colon carcinoma.

Biomarker Discovery for the Carcinogenic Heterogeneity Between Colon and Rectal Cancers Based on lncRNA-Associated ceRNA Network Analysis

Background

Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. Emerging evidence has revealed that risk factors and metastatic patterns differ greatly between colon and rectal cancers. However, the molecular mechanism underlying their pathogenic differences remains unclear. Therefore, we here aimed to identify non-coding RNA biomarkers based on lncRNA-associated ceRNA network (LceNET) to elucidate the carcinogenic heterogeneity between colon and rectal cancers.

Methods

A global LceNET in human was constructed by employing experimental evidence-based miRNA-mRNA and miRNA-lncRNA interactions. Then, four context-specific ceRNA networks related to cancer initiation and metastasis were extracted by mapping differentially expressed lncRNAs, miRNAs and mRNAs to the global LceNET. Notably, a novel network-based bioinformatics model was proposed and applied to identify lncRNA/miRNA biomarkers and critical ceRNA triplets for understanding the carcinogenic heterogeneity between colon and rectal cancers. Moreover, the identified biomarkers were further validated by their diagnostic/prognostic performance, expression pattern and correlation analysis.

Results

Based on network modeling, lncRNA KCNQ1OT1 (AUC>0.85) and SNHG1 (AUC>0.94) were unveiled as common diagnostic biomarkers for the initiation and metastasis of colon and rectal cancers. qRT-PCR analysis uncovered that these lncRNAs had significantly higher expression level in CRC cell lines with high metastatic potential. In particular, KCNQ1OT1 and SNHG1 function in colon and rectal cancers via different ceRNA mechanisms. For example, KCNQ1OT1/miR-484/ANKRD36 axis was involved in the initiation of colon cancer, while KCNQ1OT1/miR-181a-5p/PCGF2 axis was implicated in the metastasis of rectal cancer; the SNHG1/miR-484/ORC6 axis played a role in colon cancer, while SNHG1/miR-423-5p/EZH2 and SNHG1/let-7b-5p/ATP6V1F axes participated in the initiation and metastasis of rectal cancer, respectively. In these ceRNA triplets, miR-484, miR-181a-5p, miR-423-5p and let-7b-5p were identified as miRNA biomarkers with excellent distinguishing ability between normal and tumor tissues, and ANKRD36, PCGF2, EZH2 and ATP6V1F were closely related to the prognosis of corresponding cancer.

Conclusion

The landscape of lncRNA-associated ceRNA network not only facilitates the exploration of non-coding RNA biomarkers, but also provides deep insights into the oncogenetic heterogeneity between colon and rectal cancers, thereby contributing to the optimization of diagnostic and therapeutic strategies of CRC.

LINC00667/miR-449b-5p/YY1 axis promotes cell proliferation and migration in colorectal cancer

Background

Long non-coding RNAs (lncRNAs) have been defined as vital regulators in the progression of human cancers, including colorectal cancer (CRC). Long intergenic non-protein coding RNA 667 (LINC00667) is a tumor promoter in several cancer types, while its role in CRC remains to be unmasked. This study focused on exploring the potential function and regulatory mechanism of LINC00667 in CRC.

Methods

qRT-PCR analysis was applied to detect the expression of LINC00667 in CRC cells. Loss-of function assays revealed the role of LINC00667 silencing in regulating CRC cell proliferation, apoptosis and migration. In vivo study demonstrated the effect of LINC00667 silencing on CRC cell growth. Mechanism experiments were conducted to determine the upstream or the downstream molecular mechanism of LINC00667 in CRC cells.

Results

LINC00667 was expressed at high level in CRC cells. LINC00667 knockdown significantly inhibited CRC cell growth and migration. YY1 transcription factor induced the upregulation of LINC00667 in CRC cells by transcriptionally activating LINC00667. In addition, miR-449b-5p could interact with LINC00667 in CRC cells. Intriguingly, miR-449b-5p directly targeted to YY1, thus inhibiting YY1 expression. YY1 recovered the CRC cell functions impaired by LINC00667 silencing.

Conclusions

LINC00667 is transcriptionally activated by YY1 and promotes cell proliferation and migration in CRC by sponging miR-449b-5p to upregulate YY1.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

LncRNA SNHG1 regulates vascular endothelial cell proliferation and angiogenesis via miR-196a

Inflammatory cytokines are important protagonists in the formation of atherosclerotic plaques, triggering effects throughout the atherosclerotic vessels due to the destruction in proliferation, migration and angiogenesis of endothelial cells. In this study, we found SNHG1 is upregulated in TNF-α-treated HUVECs. We silenced SNHG1 and found it inhibited vascular endothelial cell proliferation and angiogenesis. In the other hand, exogenetic overexpression of SNHG1 promotes proliferation, migration and angiogenesis. Then we demonstrated that SNHG1 may interact directly with miR-196a to act as a miR-196a sponge. Further, MAPK6 were predicted to be the target of miR-196a. So we blocked miR-196a, which increased expression level of MAPK6, enhanced cell proliferation, migration and angiogenesis. These data indicated that SNHG1/miR-196a/MAPK6 axis may take a part in autophagy regulation in TNF-α-treated HUVECs. The subsequent rescue experiments come to the results ascertained the specificity of SNHG1/miR-196a/MAPK6 axis in regulating MAPK6. Overall, our findings demonstrate a novel mechanism by which SNHG1 overexpression protects the function of HUVECs, which may delay the progression of AS. SNHG1/miR-196a/MAPK6 axis may be of therapeutic significance in AS.

An Emerging Class of Long Non-coding RNA With Oncogenic Role Arises From the snoRNA Host Genes

The small nucleolar RNA host genes (SNHGs) are a group of long non-coding RNAs, which are reported in many studies as being overexpressed in various cancers. With very few exceptions, the SNHGs (SNHG1, SNHG3, SNHG5, SNHG6, SNHG7, SNHG12, SNHG15, SNHG16, SNHG20) are recognized as inducing increased proliferation, cell cycle progression, invasion, and metastasis of cancer cells, which makes this class of transcripts a viable biomarker for cancer development and aggressiveness. Through our literature research, we also found that silencing of SNHGs through small interfering RNAs or short hairpin RNAs is very effective in both in vitro and in vivo experiments by lowering the aggressiveness of solid cancers. The knockdown of SNHG as a new cancer therapeutic option should be investigated more in the future.

Noncoding RNAs in inflammation and colorectal cancer

Despite advanced clinical treatments, mortality in patients with metastatic colorectal cancer (CRC) remains high. Three critical determinants in CRC progression include the epithelial proliferation checkpoints, epithelial-to-mesenchymal transition (EMT) and inflammatory cytokines in the tumour microenvironment. Genes involved in these three processes are regulated at the transcriptional and post-transcriptional level. Recent studies revealed previously unappreciated roles of non-coding ribonucleic acids (ncRNAs) in modulating the proliferation checkpoints, EMT, and inflammatory gene expression in CRC. In this review, we will discuss the mechanisms underlying the roles of ncRNAs in CRC as well as examine future perspectives in this field. Better understanding of ncRNA biology will provide novel targets for future therapeutic development.

LncRNA SNHG1 upregulates ROCK2 to reduce cisplatin sensitivity of NSCLC cells by targeting miR-101-3p

BACKGROUND

Cisplatin is the most commonly used chemotherapy drug in clinical settings, and decreased sensitivity or resistance to cisplatin is the main cause of chemotherapy failure or death among cancer patients. Long non-coding RNA (lncRNA) SNHG1 is highly expressed in non-small cell lung cancer (NSCLC) tissues and promotes the proliferation of NSCLC cells, but the effect of SNHG1 on cisplatin sensitivity of NSCLC cells is unclear.

METHODS

We compared the expression of SNHG1 in cisplatin-sensitive and insensitive NSCLC tissues and explored the molecular mechanism of SNHG1 regulation of the sensitivity of NSCLC cells to cisplatin in vitro.

RESULTS

We found that SNHG1 is upregulated in cisplatin insensitive NSCLC tissues and cells, and that it can regulate cisplatin sensitivity of NSCLC cells in vitro. Furthermore, we also found that the expression of miR-101-3p in NSCLC tissues is negatively correlated with SNHG1 or ROCK2. Additionally, in NSCLC cells, SNHG1 and miR-101-3p are mutually suppressed, but miR-101-3p targets the inhibition of ROCK2. More importantly, the regulation of ROCK2 expression in vitro can also change the sensitivity of NSCLC cells to cisplatin.

CONCLUSIONS

In summary, our results provide novel mechanistic insights into the role of SNHG1/miR-101-3p/ROCK2 signaling in cisplatin resistance of NSCLC cells.

Integrated bioinformatics analysis revealing independent prognostic long non-coding RNAs DNAH17-AS1 and RP11-400N13.2 and their potential oncogenic roles in colorectal cancer

The aberrant expression of long non-coding RNAs (lncRNAs) has been associated with a variety of malignancies, including colorectal cancer (CRC); however, the key lncRNAs associated with patient prognosis and their biological roles in CRC are yet to be determined. The aim of the present study was to determine the key lncRNAs associated with patient prognosis as well as their biological roles in CRC. Therefore, a dataset from The Cancer Genome Atlas containing the lncRNA expression data of 521 CRC and normal colorectal mucosal tissues, as well as the corresponding clinical data, were screened. A total of 1,180 significantly differentially expressed lncRNAs were associated with CRC as determined by t-tests in edgeR. Kaplan-Meier analysis revealed that 56 of the 1,180 lncRNAs were associated with overall survival (OS); 7 of the 56 lncRNAs were identified as key lncRNAs associated with the Tumor-Node-Metastasis stage of CRC by Kruskal-Wallis test. Subsequent univariate and multivariate Cox regression analyses of the 7 lncRNAs revealed 2 lncRNAs, DNAH17-AS1 and RP11-400N13.2, as potential independent prognostic factors for the OS of patients with CRC. Furthermore, the expression levelsof these 2 lncRNAs were significantly upregulated in CRC compared with those in normal tissues, which suggested that they may serve an oncogenic role in CRC. In addition, networks comprising the 2 lncRNAs and their respective co-expressed protein-coding genes (PCGs) were constructed using cor.test in R. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses of these PCGs were conducted; DNAH17-AS1- and RP11-400N13.2-associated PCGs were reported to be involved in G-protein coupling-related functions. Thus, these independent prognostic lncRNAs and their associated functions identified in the present study may provide novel insight into potential prognostic biomarkers and therapeutic targets for the treatment of CRC.

LncRNA SNHG1 correlates with higher T stage and worse overall survival, and promotes cell proliferation while reduces cell apoptosis in breast cancer

Background

The aim of this study was to investigate the correlation of long non-coding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) with the prognosis in breast cancer patients, and its effect on breast cancer cell proliferation and apoptosis.

Methods

A total of 178 breast cancer patients were consecutively recruited, then tumor tissue and the paired adjacent tissue were obtained during surgery for lncRNA SNHG1 determination by quantitative polymerase chain reaction (qPCR). LncRNA SNHG1 expression was also measured in breast cancer cell lines and normal breast epithelial cell line. Subsequently, negative control (NC) overexpression plasmids, lncRNA SNHG1 overexpression plasmids, NC short hairpin RNA (shRNA) plasmids and lncRNA SNHG1 shRNA plasmids were transfected into MDA-MB-453 cells as well as MCF7 cells, and cell proliferation and apoptosis were measured afterward.

Results

LncRNA SNHG1 expression in tumor tissue was increased compared with paired adjacent tissue, and it correlated with higher T stage and worse overall survival (OS) in breast cancer patients. LncRNA SNHG1 expression was also elevated in breast cancer cell lines compared with normal breast epithelial cell line. Cell Counting Kit-8 (CCK8) assay revealed that lncRNA SNHG1 overexpression promoted while lncRNA SNHG1 shRNA reduced cell proliferation, and Annexin V-fluorescein isothiocyanate/propidium iodide staining (AV/PI) assay illustrated that lncRNA SNHG1 overexpression decreased while lncRNA SNHG1 shRNA increased cell apoptosis rate. In addition, Western Blot assay disclosed that lncRNA SNHG1 overexpression downregulated while lncRNA SNHG1 shRNA upregulated pro-apoptotic marker (C-Caspase3) expression, and lncRNA SNHG1 overexpression increased while lncRNA SNHG1 shRNA decreased anti-apoptotic marker (p-P38) expression.

Conclusions

LncRNA SNHG1 is upregulated in tumor tissue and correlates with higher T stage and worse OS, and it promotes cell proliferation but inhibits cell apoptosis in breast cancer.

LncRNA CCAT1 negatively regulates miR-181a-5p to promote endometrial carcinoma cell proliferation and migration

Long non-coding RNAs (lncRNAs) are identified as vital modulators in a number of biological processes, including tumorigenesis. However, the role of lncRNAs in endometrial carcinoma (EC) remains unknown. In the current study, the expression patterns, biological roles and functional mechanism of the lncRNA colon cancer associated transcript 1 (CCAT1) was examined in EC. The expression level of CCAT1 was significantly upregulated in EC tissue samples compared with matched adjacent healthy tissue samples from patients with endometrial cancer. Similarly, CCAT1 was significantly upregulated in several EC cell lines (KLE, Ishiwaka and HEC-1-A), compared with the normal human endometrial stromal cell line T-HESC. Cell counting kit-8 and Transwell migration assays demonstrated that CCAT1 knockdown significantly decreased EC cell proliferation and migration. In addition, CCAT1 was confirmed as a target gene of miR-181a-5p in EC. Overexpression of miR-181a-5p significantly decreased CCAT1 expression in EC cells, whilst knockdown of CCAT1 significantly increased miR-181a-5p expression in EC cells. Furthermore, miR-181a-5p expression was significantly downregulated in EC tissue samples compared with matched adjacent healthy tissue samples from patients with endometrial cancer. Similarly, miR-181a-5p expression was significantly downregulated in several EC cell lines (KLE, Ishiwaka and HEC-1-A), compared with normal human endometrial stromal cell line T-HESC. In addition, rescue experiments demonstrated that inhibition of miR-181a-5p significantly reversed the effect of CCAT1 knockdown on EC cell proliferation and migration. The results suggest that CCAT1 promotes EC progression by acting as a molecular sponge of miR-181a-5p.

Potential Regulatory Roles of MicroRNAs and Long Noncoding RNAs in Anticancer Therapies

MicroRNAs and long noncoding RNAs have long been investigated due to their roles as diagnostic and prognostic biomarkers of cancers and regulators of tumorigenesis, and the potential regulatory roles of these molecules in anticancer therapies are attracting increasing interest as more in-depth studies are performed. The major clinical therapies for cancer include chemotherapy, immunotherapy, and targeted molecular therapy. MicroRNAs and long noncoding RNAs function through various mechanisms in these approaches, and the mechanisms involve direct targeting of immune checkpoints, cooperation with exosomes in the tumor microenvironment, and alteration of drug resistance through regulation of different signaling pathways. Herein we review the regulatory functions and significance of microRNAs and long noncoding RNAs in three anticancer therapies, especially in targeted molecular therapy, and their mechanisms.

The long noncoding RNA SNHG1 regulates colorectal cancer cell growth through interactions with EZH2 and miR-154-5p

BACKGROUND

Mounting evidence demonstrates that long noncoding RNAs (lncRNAs) have critical roles during the initiation and progression of cancers. In this study, we report that the small nucleolar RNA host gene 1 (SNHG1) is involved in colorectal cancer progression.

METHODS

We analyzed RNA sequencing data to explore abnormally expressed lncRNAs in colorectal cancer. The effects of SNHG1 on colorectal cancer were investigated through in vitro and in vivo assays (i.e., CCK-8 assay, colony formation assay, flow cytometry assay, EdU assay, xenograft model, immunohistochemistry, and western blot). The mechanism of SNHG1 action was explored through bioinformatics, RNA fluorescence in situ hybridization, luciferase reporter assay, RNA pull-down assay, chromatin immunoprecipitation assay and RNA immunoprecipitation assay.

RESULTS

Our analysis revealed that SNHG1 was upregulated in human colorectal cancer tissues, and high SNHG1 expression was associated with reduced patient survival. We also found that high SNHG1 expression was partly induced by SP1. Moreover, SNHG1 knockdown significantly repressed colorectal cancer cells growth both in vitro and in vivo. Mechanistic investigations demonstrated that SNHG1 could directly interact with Polycomb Repressive Complex 2 (PRC2) and modulate the histone methylation of promoter of Kruppel like factor 2 (KLF2) and Cyclin dependent kinase inhibitor 2B (CDKN2B) in the nucleus. In the cytoplasm, SNHG1 acted as a sponge for miR-154-5p, reducing its ability to repress Cyclin D2 (CCND2) expression.

CONCLUSIONS

Taken together, the results of our studies illuminate how SNHG1 formed a regulatory network to confer an oncogenic function in colorectal cancer and suggest that SNHG1 may serve as a potential target for colorectal cancer diagnosis and treatment.