Long noncoding RNA SNHG14 facilitates colorectal cancer metastasis through targeting EZH2-regulated EPHA7

Universal penalized regression (Elastic-net) model with differentially methylated promoters for oral cancer prediction

BACKGROUND

DNA methylation showed notable potential to act as a diagnostic marker in many cancers. Many studies proposed DNA methylation biomarker in OSCC detection, while most of these studies are limited to specific cohorts or geographical location. However, the generalizability of DNA methylation as a diagnostic marker in oral cancer across different geographical locations is yet to be investigated.

METHODS

We used genome-wide methylation data from 384 oral cavity cancer and normal tissues from TCGA HNSCC and eastern India. The common differentially methylated CpGs in these two cohorts were used to develop an Elastic-net model that can be used for the diagnosis of OSCC. The model was validated using 812 HNSCC and normal samples from different anatomical sites of oral cavity from seven countries. Droplet Digital PCR of methyl-sensitive restriction enzyme digested DNA (ddMSRE) was used for quantification of methylation and validation of the model with 22 OSCC and 22 contralateral normal samples. Additionally, pyrosequencing was used to validate the model using 46 OSCC and 25 adjacent normal and 21 contralateral normal tissue samples.

RESULTS

With ddMSRE, our model showed 91% sensitivity, 100% specificity, and 95% accuracy in classifying OSCC from the contralateral normal tissues. Validation of the model with pyrosequencing also showed 96% sensitivity, 91% specificity, and 93% accuracy for classifying the OSCC from contralateral normal samples, while in case of adjacent normal samples we found similar sensitivity but with 20% specificity, suggesting the presence of early disease methylation signature at the adjacent normal samples. Methylation array data of HNSCC and normal tissues from different geographical locations and different anatomical sites showed comparable sensitivity, specificity, and accuracy in detecting oral cavity cancer with across. Similar results were also observed for different stages of oral cavity cancer.

CONCLUSIONS

Our model identified crucial genomic regions affected by DNA methylation in OSCC and showed similar accuracy in detecting oral cancer across different geographical locations. The high specificity of this model in classifying contralateral normal samples from the oral cancer compared to the adjacent normal samples suggested applicability of the model in early detection.

Restoring BARX2 in OSCC reverses partial EMT and suppresses metastasis through miR-186-5p/miR-378a-3p-dependent SERPINE2 inhibition

Tumor cells undergoing partial epithelial-mesenchymal transition (pEMT) are pivotal in local invasion and lymphatic metastasis of oral squamous cell carcinoma (OSCC), yet the mechanisms behind pEMT reversal remain poorly understood. In this study, the loss of BARX2 expression was revealed during the process of oral epithelial carcinogenesis and identified to activate the pEMT program, facilitate metastasis, and be associated with poor prognosis. Restoring BARX2 expression in OSCC cell lines effectively reversed tumor pEMT, evident in E/N-Cadherin switching, reduced cell invasion, proliferation, and stemness, and inhibited murine lung metastasis. BARX2 re-expression negatively correlated with several pEMT markers, notably SERPINE2, which was enriched in the invasive OSCC front, enhancing stemness and promoting metastasis, particularly in cervical lymph nodes. Furthermore, rescuing SERPINE2 impaired the inhibitory effect of BARX2 on the pEMT programs and reconstructed ECM through re-expression of MMP1. Mechanistically, we identified that BARX2 inhibited SERPINE2 through activating miR-186-5p and miR-378a-3p. These miRNAs, upregulated by BARX2, post-transcriptionally degraded SERPINE2 mRNA via targeting specific sequences. Blocking miR-186-5p and miR-378a-3p effectively abolished the negative regulatory effect of BARX2 on SERPINE2. Overall, our findings highlight BARX2 as a partial EMT-reverser in OSCC, providing fresh therapeutic prospects for restoring BARX2 signaling to inhibit invasion and metastasis.

Identification of Key lncRNAs Associated with Immune Infiltration and Prognosis in Gastric Cancer

Long non-coding RNAs (lncRNAs), as promising novel biomarkers for cancer treatment and prognosis, can function as tumor suppressors and oncogenes in the occurrence and development of many types of cancer, including gastric cancer (GC). However, little is known about the complex regulatory system of lncRNAs in GC. In this study, we systematically analyzed lncRNA and miRNA transcriptomic profiles of GC based on bioinformatics methods and experimental validation. An lncRNA-miRNA interaction network related to GC was constructed, and the nine crucial lncRNAs were identified. These 9 lncRNAs were found to be associated with the prognosis of GC patients by Cox proportional hazards regression analysis. Among them, the expression of lncRNA SNHG14 can affect the survival of GC patients as a potential prognostic marker. Moreover, it was shown that SNHG14 was involved in immune-related pathways and significantly correlated with immune cell infiltration in GC. Meanwhile, we found that SNHG14 affected immune function in many cancers, such as breast cancer and esophageal carcinoma. Such information revealed that SNHG14 may serve as a potential target for cancer immunotherapy. As well, our study could provide practical and theoretical guiding significance for clinical application of non-coding RNAs.

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

Functional role of lncRNAs in gastrointestinal malignancies: the peculiar case of small nucleolar RNA host gene family

Long noncoding RNAs (lncRNAs) play crucial roles in normal physiology and are often de-regulated in disease states such as cancer. Recently, a class of lncRNAs referred to as the small nucleolar RNA host gene (SNHG) family have emerged as important players in tumourigenesis. Here, we discuss new findings describing the role of SNHGs in gastrointestinal tumours and summarize the three main functions by which these lncRNAs promote carcinogenesis, namely: competing with endogenous RNAs, modulating protein function, and regulating epigenetic marking. Furthermore, we discuss how SNHGs participate in different hallmarks of cancer, and how this class of lncRNAs may serve as potential biomarkers in cancer diagnosis and therapy.

CYP1B1-AS1 Delays the Malignant Progression of Colorectal Cancer by Binding with NOP58

BACKGROUND

Colorectal cancer (CRC) is a prevalent type of gastrointestinal cancer, and its poor prognosis is mainly attributed to the occurrence of invasion and metastasis. CYP1B1-AS1, as non-coding RNA, plays an important role in tumorigenesis and progression. However, the mechanism by which CYP1B1-AS1 acts in CRC is not yet understood.

AIMS

The objective of this study was to investigate how CYP1B1-AS1 contributes to the development of CRC, and provide a base for CRC diagnosis and treatment.

METHODS

RT-qPCR was used to detect the expression level of CYP1B1-AS1 in CRC and adjacent tissues. CCK-8, Edu, scratch healing, and transwell experiments were used to detect the changes of proliferation, migration, and invasion ability of CRC cells after overexpression or knockdown of CYP1B1-AS1 respectively. The RNA binding protein NOP58 combined with CYP1B1-AS1 was verified by RIP and RNA Pull-down experiments. Functional recovery experiments validated the interaction between CYP1B1-AS1 and NOP58 in CRC cells. The changes of EMT-related proteins were detected by Western blot, and the half-life of transcription factor SNAIL mRNA were detected by RT-qPCR after overexpression or knockdown of NOP58.

RESULTS

CYP1B1-AS1 was found to be significantly downregulated in CRC compared to adjacent noncancerous tissues. Experiments conducted in vitro and in vivo confirmed that upregulation of CYP1B1-AS1 significantly inhibited the proliferation, migration, and invasion of CRC cells. In addition, CYP1B1-AS1 can directly bind to NOP58 and negatively regulate NOP58. The effect of overexpression CYP1B1-AS1 was reversed by NOP58 overexpression. NOP58 regulates the EMT process of CRC cells by affecting the stability of EMT-related transcription factor SNAIL mRNA, and then affects the progress of CRC.

CONCLUSION

This research proves that CYP1B1-AS1 can inhibit the occurrence of EMT in CRC by binding with NOP58, thus delaying the progress of CRC. This finding indicates that CYP1B1-AS1 may be a novel biomarker to improve the diagnosis and treatment of CRC.

STAT3-EphA7 axis contributes to the progression of esophageal squamous cell carcinoma

BACKGROUND

Our previous study has revealed that EphA7 was upregulated in patient-derived esophageal squamous cell carcinoma (ESCC) xenografts with hyper-activated STAT3, but its mechanism was still unclear.

MATERIALS AND METHODS

To assess the association between EphA7 and STAT3, western blotting, immunofluorescence, ChIP assay, and qRT-PCR were conducted. Truncated mutation and luciferase assay were performed to examine the promoter activity of EphA7. CCK-8 assay and colony formation were performed to assess the proliferation of ESCC. Cell-derived xenograft models were established to evaluate the effects of EphA7 on ESCC tumor growth. RNA-seq analyses were used to assess the effects of EphA7 on related signals.

RESULTS

In this study, EphA7 was found upregulated in ESCC cell lines with high STAT3 activation, and immunofluorescence also showed that EphA7 was co-localized with phospho-STAT3 in ESCC cells. Interestingly, suppressing STAT3 activation by the STAT3 inhibitor Stattic markedly inhibited the protein expression of EphA7 in ESCC cells, in contrast, activation of STAT3 by IL-6 obviously upregulated the protein expression of EphA7. Moreover, the transcription of EphA7 was also mediated by the activation of STAT3 in ESCC cells, and the -2000∼-1500 region was identified as the key promoter of EphA7. Our results also indicated that EphA7 enhanced the cell proliferation of ESCC, and silence of EphA7 significantly suppressed ESCC tumor growth. Moreover, EphA7 silence markedly abolished STAT3 activation-derived cell proliferation of ESCC. Additionally, RNA-seq analyses indicated that several tumor-related signaling pathways were significantly changed after EphA7 downregulation in ESCC cells.

CONCLUSION

Our results showed that the transcriptional expression of EphA7 was increased by activated STAT3, and the STAT3 signaling may act through EphA7 to promote the development of ESCC.

The role of lncRNA SNHG14 in gastric cancer: enhancing tumor cell proliferation and migration, and mechanisms of CDH2 expression

LncRNAs are a class of non-coding RNAs that play an important role in regulating gene expression. However, their specific molecular mechanisms in gastric carcinogenesis and metastasis need further exploration. TCGA data showed that the expression of MFGE8, which was closely related to survival, was significantly positively correlated with lncRNA SNHG14. And moreover, the results of high-throughput sequencing and qRT-PCR showed that lncRNA SNHG14 was significantly elevated in gastric cancer. Further, in vitro functional realization showed that lncRNA SNHG14 overexpression significantly increased gastric cancer's proliferation, invasion and migration. Animal experiments also showed that lncRNA SNHG14 overexpression promoted tumorigenesis and metastasis in vivo. Mechanistically, MFGE8 activates the expression of lncRNA SNHG14, which activates the cellular EMT by stabilizing CDH2. Our study suggests that lncRNA SNHG14 could be a potential target for gastric cancer therapy.

Long Non-Coding RNAs in Colorectal Cancer: Navigating the Intersections of Immunity, Intercellular Communication, and Therapeutic Potential

This comprehensive review elucidates the intricate roles of long non-coding RNAs (lncRNAs) within the colorectal cancer (CRC) microenvironment, intersecting the domains of immunity, intercellular communication, and therapeutic potential. lncRNAs, which are significantly involved in the pathogenesis of CRC, immune evasion, and the treatment response to CRC, have crucial implications in inflammation and serve as promising candidates for novel therapeutic strategies and biomarkers. This review scrutinizes the interaction of lncRNAs with the Consensus Molecular Subtypes (CMSs) of CRC, their complex interplay with the tumor stroma affecting immunity and inflammation, and their conveyance via extracellular vesicles, particularly exosomes. Furthermore, we delve into the intricate relationship between lncRNAs and other non-coding RNAs, including microRNAs and circular RNAs, in mediating cell-to-cell communication within the CRC microenvironment. Lastly, we propose potential strategies to manipulate lncRNAs to enhance anti-tumor immunity, thereby underlining the significance of lncRNAs in devising innovative therapeutic interventions in CRC.

Mutual interaction of lncRNAs and epigenetics: focusing on cancer

Long noncoding RNAs are characterized as noncoding transcripts longer than 200 nucleotides in response to a variety of functions within the cells. They are involved in almost all cellular mechanisms so as epigenetics. Given that epigenetics is an important phenomenon, which participates in the biology of complex diseases, many valuable studies have been performed to demonstrate the control status of lncRNAs and epigenetics. DNA methylation and histone modifications as epigenetic mechanisms can regulate the expression of lncRNAs by affecting their coding genes. Reciprocally, the three-dimensional structure of lncRNAs could mechanistically control the activity of epigenetic-related enzymes. Dysregulation in the mutual interaction between epigenetics and lncRNAs is one of the hallmarks of cancer. These mechanisms are either directly or indirectly involved in various cancer properties such as proliferation, apoptosis, invasion, and metastasis. For instance, lncRNA HOTAIR plays a role in regulating the expression of many genes by interacting with epigenetic factors such as DNA methyltransferases and EZH2, and thus plays a role in the initiation and progression of various cancers. Conversely, the expression of this lncRNA is also controlled by epigenetic factors. Therefore, focusing on this reciprocated interaction can apply to cancer management and the identification of prognostic, diagnostic, and druggable targets. In the current review, we discuss the reciprocal relationship between lncRNAs and epigenetic mechanisms to promote or prevent cancer progression and find new potent biomarkers and targets for cancer diagnosis and therapy.

miR-152-3p facilitates cell adhesion and hepatic metastases in colorectal cancer via targeting AQP11

BACKGROUND

Tumor metastasis is a fundamental reason for the poor prognosis of colorectal cancer (CRC) patients. Publications suggested that upregulated Aquaporin-11 (AQP11) can improve CRC patients' prognoses, but few articles investigated the regulation of AQP11 in CRC cell adhesion and hepatic metastases. Therefore, this study will explore the regulatory mechanism of AQP11 regulating CRC cell adhesion and hepatic metastases at the molecular level.

METHODS

AQP11 and miR-152-3p expression were analyzed based on The Cancer Genome Atlas-Colon Adenocarcinoma/Rectum Adenocarcinoma (TCGA-COAD/READ) dataset and several other datasets. The upstream genes of AQP11 were predicted via StarBase and MicroRNA Data Integration Portal (mirDIP) databases. The signaling pathways in which the downregulated AQP11 enriched were analyzed via Gene Set Enrichment Analysis (GSEA). Cell proliferation, migration, invasion, and adhesion were respectively tested via western blot, Transwell, and cell adhesion assays. The expression of adhesion-related proteins was determined via enzyme-linked immunosorbent assay (ELISA). AQP11 protein level was examined via western blot, and AQP11 functions were validated via nude mice xenograft experiment.

RESULTS

AQP11 was downregulated in CRC, and the upregulated AQP11 remarkably repressed cell proliferation, migration, invasion, and adhesion. The silenced AQP11 notably facilitated the above cell functions in CRC. In addition, AQP11 was negatively regulated by miR-152-3p. In vitro cellular assays revealed that miR-152-3p, by targeting AQP11, facilitated CRC cell proliferation, migration, invasion, and adhesion. An in vivo assay suggested that AQP11 could notably repress CRC growth and metastasis.

CONCLUSION

The above results confirmed that miR-152-3p/AQP11 axis could regulate CRC hepatic metastases and would be a promising target in anti-cancer treatment.

Overexpression of lncRNA HOXA-AS2 promotes the progression of oral squamous cell carcinoma by mediating SNX5 expression

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most common head and neck cancers. Long non-coding RNA HOXA-AS2 (lncRNA HOXA-AS2) have been extensively studied in various cancers. However, the expression and function of HOXA-AS2 in OSCC still remain unknown. The aim of this study is to investigate the roles of HOXA-AS2 in OSCC.

METHODS

OSCC tissues and adjacent normal tissues were obtained from OSCC patients. RT-qPCR and Western blot assays were used to detect the expression of target genes in OSCC tissues or cells. Cells proliferation, migration and invasion were detected by CCK-8 and transwell assays, respectively. The target gene of HOXA-AS2 was confirmed by dual-luciferase reporter gene assay.

RESULTS

We found that HOXA-AS2 expression was remarkably upregulated in OSCC tissues and cell lines. The downregulation of HOXA-AS2 inhibited cells proliferation, migration and invasion. Our bioinformatics analysis found that HOXA-AS2 can target miR-520c-3p, which was confirmed by dual-luciferase reporter gene assay. The expression of HOXA-AS2 was found to be negatively associated with miR-520c-3p in OSCC tissues. Moreover, sorting nexin 5 (SNX5), a downstream target of miR-520c-3p, was inhibited by miR-520c-3p overexpression. SNX5 was also increased in OSCC tissues and cell lines. Additionally, we found that the higher expression of SNX5 was strongly associated with the tumor grade of OSCC patients in Oncomine database. Most importantly, the knockdown of HOXA-AS2 induced cells apoptosis by promoting autophagy by regulating SNX5.

CONCLUSION

HOXA-AS2 served an oncogene and promoted OSCC progression via the miR-520c-3p/SNX5 axis. Thus, HOXA-AS2 may be a new biomarker for diagnosis and treatment of OSCC.

Circulating microRNA-944 and its target gene EPHA7 as a potential biomarker for colorectal cancer

MicroRNAs (miRNAs) have critical roles in colorectal cancer (CRC) tumorigenesis and development. It has been reported that Eph receptor A7 (EphA7) was a potential target of miR-944 which is transcriptionally activated in cancer. The aim of this study was to explore the expression profile of miR-944 and its target gene EPHA7 in the serum of Egyptian CRC patients. 150 CRC patients, 50 adenomatous polyps (AP) patients, and 100 healthy controls were included. Serum miR-944 was downregulated (0.304 ± 0.0512) while serum EPHA7 was upregulated (3.163 ± 0.610) in CRC and AP patients versus controls and discriminated aganst these groups by Receiver operating characteristic curve (ROC) analysis. miR-944 presented the highest diagnostic accuracy for CRC patients from control (AUC = 0.90). Moreover obvious prognostic power in distinguishing AP from CRC (AUC = 0.87). In conclusion, miR-944 and EPHA7 are potential genetic markers of CRC predisposition and novel potential non-invasive diagnostic biomarkers for CRC.

Identification and validation of an inflammation-related lncRNAs signature for improving outcomes of patients in colorectal cancer

Background: Colorectal cancer is the fourth most deadly cancer worldwide. Although current treatment regimens have prolonged the survival of patients, the prognosis is still unsatisfactory. Inflammation and lncRNAs are closely related to tumor occurrence and development in CRC. Therefore, it is necessary to establish a new prognostic signature based on inflammation-related lncRNAs to improve the prognosis of patients with CRC. Methods: LASSO-penalized Cox analysis was performed to construct a prognostic signature. Kaplan-Meier curves were used for survival analysis and ROC curves were used to measure the performance of the signature. Functional enrichment analysis was conducted to reveal the biological significance of the signature. The R package "maftool" and GISTIC2.0 algorithm were performed for analysis and visualization of genomic variations. The R package "pRRophetic", CMap analysis and submap analysis were performed to predict response to chemotherapy and immunotherapy. Results: An effective and independent prognostic signature, IRLncSig, was constructed based on sixteen inflammation-related lncRNAs. The IRLncSig was proved to be an independent prognostic indicator in CRC and was superior to clinical variables and the other four published signatures. The nomograms were constructed based on inflammation-related lncRNAs and detected by calibration curves. All samples were classified into two groups according to the median value, and we found frequent mutations of the TP53 gene in the high-risk group. We also found some significantly amplificated regions in the high-risk group, 8q24.3, 20q12, 8q22.3, and 20q13.2, which may regulate the inflammatory activity of cancer cells in CRC. Finally, we identified chemotherapeutic agents for high-risk patients and found that these patients were more likely to respond to immunotherapy, especially anti-CTLA4 therapy. Conclusion: In short, we constructed a new signature based on sixteen inflammation-related lncRNAs to improve the outcomes of patients in CRC. Our findings have proved that the IRLncSig can be used as an effective and independent marker for predicting the survival of patients with CRC.

β-Sitosterol & quercetin enhances brain development in iodine deficient rat models

BACKGROUND

Recently thyroid hormone studies on brain growth, development and activity are regaining popularity. Thyroid hormones have long been believed to play critical role in mammalian brain growth and maturation regulating facets of neuronal cell growth, proliferation and differentiation and further signaling and glial cell differentiation. Deficiency of these hormones in mother leads to mental retardation in the subsequent offspring's.

METHODS

In this presented study, brain development of iodine deficient rat models created through deficiency in feeding, mating and further selection. Young adult female wistar rats were induced with iodine deficiency and then mated with healthy male rats. These pregnant hypothyroid induced females were treated with β-sitosterol (150 mg/kg/day) and quercetin (150 mg/kg/day) alone and in combination for whole gestation period. Analysis were dealt with the genetic and histological studies of the pups brain. PCR based RNA analysis was also carried out. Histology was done using eosin and hematoxylin.

RESULTS

Positive impacts of the β-sitosterol and quercetin on the iodine deficient brain were observed upon histological and PCR analysis. Altogether, the analysis proves that combined doses of β-sitosterol and quercetin for normal brain development in iodine deficient infants hence can be potentially applied as therapeutics in iodine deficiency circumstances.

The role of EphA7 in different tumors

Ephrin receptor A7 (EphA7) is a member of the Eph receptor family. It is widely involved in signal transduction between cells, regulates cell proliferation and differentiation, and participates in developing neural tubes and brain. In addition, EphA7 also has a dual role of tumor promoter and tumor suppressor. It can participate in cell proliferation, migration and apoptosis through various mechanisms, and affect tumor differentiation, staging and prognosis. EphA7 may be a potential diagnostic marker and tumor treatment target. This article reviews the effects of EphA7 on a variety of tumor biological processes and pathological characteristics, as well as specific effects and regulatory mechanisms.

Upregulation of the transmembrane protease serine 3 mRNA level in radioresistant colorectal cancer tissues

Aim: To investigate the clinical role of transmembrane protease serine 3 (TMPRSS3) in radioresistance and prognosis of colorectal cancer (CRC). Methods: Standardized mean difference (SMD) and summary area under the curve (AUC) of TMPRSS3 were calculated by combining all available high-throughput data globally. The prognostic significance of TMPRSS3 was determined by Kaplan-Meier and Cox regression analyses. Results: TMPRSS3 was remarkably upregulated in 198 CRC radioresistant cases compared with nonradioresistance (SMD = 0.38, AUC = 0.71). Overexpression of TMPRSS3 was observed in 1601 CRC patients compared with control subjects without CRC. TMPRSS3 was a risk factor for disease-free survival of CRC with the summarized hazard ratio 1.28. Conclusion: TMPRSS3 contributes to the radioresistance and unfavorable prognosis of CRC.

The role of epigenetic modifications in Colorectal Cancer Metastasis

Distant metastasis is the major contributor to the high mortality rate of colorectal cancer (CRC). To overcome the poor prognosis caused by distant metastasis, the mechanisms of CRC metastasis should be further explored. Epigenetic events are the main mediators of gene regulation and further affect tumor progression. Recent studies have found that some epigenetic enzymes are often dysregulated or mutated in multiple tumor types, which prompted us to study the roles of these enzymes in CRC metastasis. In this review, we summarized the alteration of enzymes related to various modifications, including histone modification, nonhistone modification, DNA methylation, and RNA methylation, and their epigenetic mechanisms during the progression of CRC metastasis. Existing data suggest that targeting epigenetic enzymes is a promising strategy for the treatment of CRC metastasis.

Non-coding RNAs as emerging regulators and biomarkers in colorectal cancer

CRC is the third most common cancer occurring worldwide and the second leading cause of cancer deaths. In the year 2020, 1,931,590 new cases of CRC and 935,173 deaths were reported. The last two decades have witnessed an intensive study of noncoding RNAs and their implications in various pathological conditions including cancer. Noncoding RNAs such as miRNAs, tsRNAs, piRNAs, lncRNAs, pseudogenes, and circRNAs have emerged as promising prognostic and diagnostic biomarkers in preclinical studies of cancer. Some of these noncoding RNAs have also been shown as promising therapeutic targets for cancer treatment. In this review, we have discussed the emerging roles of various types of noncoding RNAs in CRC and their future implications in colorectal cancer management and research.

Colorectal liver metastasis: molecular mechanism and interventional therapy

Colorectal cancer (CRC) is one of the most frequently occurring malignancy tumors with a high morbidity additionally, CRC patients may develop liver metastasis, which is the major cause of death. Despite significant advances in diagnostic and therapeutic techniques, the survival rate of colorectal liver metastasis (CRLM) patients remains very low. CRLM, as a complex cascade reaction process involving multiple factors and procedures, has complex and diverse molecular mechanisms. In this review, we summarize the mechanisms/pathophysiology, diagnosis, treatment of CRLM. We also focus on an overview of the recent advances in understanding the molecular basis of CRLM with a special emphasis on tumor microenvironment and promise of newer targeted therapies for CRLM, further improving the prognosis of CRLM patients.

LncRNA SNHG14 Sponges miR-206 to Affect Proliferation, Apoptosis, and Metastasis of Hepatocellular Carcinoma Cells by Regulating SOX9

OBJECTIVE

To explore how lncRNA SNHG14 modulates the biological features of hepatocellular carcinoma (HCC) cells by regulating SOX9 via mediating miR-206.

METHODS

HCC tissues were collected to perform the quantitative reverse transcriptase polymerase chain reaction to determine the expressions of SNHG14, miR-206, and SOX9. HCC cell line SMCC7721 was selected for co-transfection by si-SNHG14/miR-206 inhibitor/si-SOX9, followed by the measurement of cell proliferation using Cell Count Kit-8 (CCK-8) assay and clone formation assay. The migration and invasion were evaluated by wound healing test and Transwell assay. The apoptotic rate was determined by flow cytometry. Levels of the apoptosis-related proteins were measured through Western blotting.

RESULTS

SNHG14 and SOX9 were up-regulated in HCC tumor tissues compared with adjacent normal tissues, with decreased miR-206 expression. Moreover, SNHG14 expression was significantly associated with the TNM stage, lymphatic metastasis, and histological differentiation of HCC patients. Besides, inverse correlations between SNHG14 and miR-206, as well as between miR-206 and SOX9, were noted. The dual luciferase reporter gene assay, RIP, and RNA pull-down experiments also revealed the targeting relationship between SNHG14 and miR-206 or between miR-206 and SOX9. Silencing SNHG14 and SOX9 inhibited the proliferation, invasion, and migration of HCC cells, with increased apoptosis, which was all abolished by silencing miR-206.

CONCLUSION

Inhibition of SNHG14 suppresses SOX9 by up-regulating miR-206, to further inhibit the proliferation, migration, and invasion of HCC cells with the promoted apoptosis, which is a novel target for the treatment of HCC.

Long non-coding RNAs as the critical regulators of epithelial mesenchymal transition in colorectal tumor cells: an overview

Colorectal cancer (CRC) is the second most common cause of cancer mortality and a major health challenge worldwide. Despite advances in therapeutic and diagnostic methods, there is still a poor prognosis in CRC patients. Tumor recurrence and metastasis are the main causes of high mortality rate in these patients, which are due to late diagnosis in advanced tumor stages. Epithelial-mesenchymal transition (EMT) is known to be the most important cause of CRC metastasis, during which tumor cells obtain metastasis ability by losing epithelial features and gaining mesenchymal features. Long non-coding RNAs (lncRNAs) are pivotal regulators of EMT process. Regarding the higher stability of lncRNAs compared with coding RNAs in body fluids, they can be used as non-invasive diagnostic markers for EMT process. In the present review, we summarized all of the lncRNAs involved in regulation of EMT process during CRC progression and metastasis. It was observed that lncRNAs mainly induced the EMT process in CRC cells by regulation of EMT-related transcription factors, Poly comb repressive complex (PRC), and also signaling pathways such as WNT, NOTCH, MAPK, and Hippo.

Loss of EphA7 Expression in Basal Cell Carcinoma by Hypermethylation of CpG Islands in the Promoter Region

Basal cell carcinoma (BCC) is the most common malignancy worldwide, with increasing incidence. BCCs present low mortality but high morbidity, and its pathogenesis remains unclear. Eph receptors have been implicated in tumorigenesis. EphA7 plays a role as a tumor suppressor in certain cancers. We checked EphA7 expression levels and methylation status in a set of BCCs, benign skin diseases, and compound nevus tissue samples using immunohistochemistry. EphA7 protein was positively expressed in normal basal cells, benign skin diseases, and compound nevus cells, but lost in areas of BCC tissues. We detected hypermethylation in BCC tissue samples with reduced expression of EphA7. There is a significant relationship between the expression level of EphA7 receptor protein and the methylation status of CpG islands in the EphA7 promoter region (P < 0.001). To our knowledge, this is the first study to report the EphA7 expression profile and hypermethylation of EphA7 in BCC. The role of the EphA7 gene and the status of hypermethylation in tumorigenesis and treatment of BCC warrant further investigation.

The Relationship Between the Network of Non-coding RNAs-Molecular Targets and N6-Methyladenosine Modification in Colorectal Cancer

Recent accumulating researches implicate that non-coding RNAs (ncRNAs) including microRNA (miRNA), circular RNA (circRNA), and long non-coding RNA (lncRNAs) play crucial roles in colorectal cancer (CRC) initiation and development. Notably, N6-methyladenosine (m⁶A) methylation, the critical posttranscriptional modulators, exerts various functions in ncRNA metabolism such as stability and degradation. However, the interaction regulation network among ncRNAs and the interplay with m⁶A-related regulators has not been well documented, particularly in CRC. Here, we summarize the interaction networks and sub-networks of ncRNAs in CRC based on a data-driven approach from the publications (IF > 6) in the last quinquennium (2016–2021). Further, we extend the regulatory pattern between the core m⁶A regulators and m⁶A-related ncRNAs in the context of CRC metastasis and progression. Thus, our review will highlight the clinical potential of ncRNAs and m⁶A modifiers as promising biomarkers and therapeutic targets for improving the diagnostic precision and treatment of CRC.

LncRNA SNHG14 accelerates breast cancer progression through sponging miR-543 and regulating KLF7 expression

PURPOSE

Dysregulation of long non-coding RNAs (lncRNAs) is being found to have relevance to human cancers, including breast cancer (BC). The aim of this study was to further explore the functional role and molecular mechanisms of small nucleolar RNA host gene 14 (SNHG14) on BC progression.

METHODS

The expression levels of SNHG14, miR-543, and krüppel-like factor 7 (KLF7) mRNA were determined by quantitative real-time PCR. Western blot analysis was used to evaluate KLF7 protein level. Cell proliferation, apoptosis, and migration and invasion abilities were detected by Cell Counting kit-8 assay, flow cytometry, and transwell assay, respectively. The direct interactions between miR-543 and SNHG14 or KLF7 were confirmed using dual-luciferase reporter assays.

RESULTS

Our data indicated that SNHG14 expression was increased in BC tissues and cells, and SNHG14 knockdown mitigated the proliferation, migration, and invasion and facilitated apoptosis of BC cells. SNHG14 directly interacted with miR-543. MiR-543 mediated the regulatory effects of SNHG14 silencing on BC cell behaviors. Moreover, KLF7 was a direct target of miR-543. Overexpressed miR-543-mediated anti-proliferation, anti-migration, anti-invasion, and pro-apoptosis effects were mediated by KLF7. Furthermore, SNHG14 modulated KFL7 expression through acting as a competing endogenous RNA (ceRNA) of miR-543 in BC cells.

CONCLUSION

Our study suggested that SNHG14 knockdown hindered BC progression in vitro at least partly through acting as a ceRNA of miR-543 and modulating KLF7 expression, providing evidence for SNHG14 as a potential target for BC therapy.

Tumor-suppressive function of EZH2 is through inhibiting glutaminase

Tumors can use metabolic reprogramming to survive nutrient stress. Epigenetic regulators play a critical role in metabolic adaptation. Here we screened a sgRNA library to identify epigenetic regulators responsible for the vulnerability of colorectal cancer (CRC) cells to glucose deprivation and found that more EZH2-knockout cells survived glucose deprivation. Then, we showed that EZH2 expression was significantly downregulated in response to glucose deprivation in a glucose-sensitive CRC cell line, and EZH2-knockdown cells were more resistant to glucose deprivation. Mechanistically, EZH2 deficiency upregulated the expression of glutaminase (GLS) and promoted the production of glutamate, which in turn led to increased synthesis of intracellular glutathione (GSH) and eventually attenuated the reactive oxygen species (ROS)-mediated cell death induced by glucose deprivation. Although EZH2 functioned as an oncogene in cancer progression and EZH2 knockout abolished colorectal cancer development in a mouse model, here we revealed a mechanistic link between EZH2 and metabolic reprogramming via the direct regulation of GLS expression and observed a negative correlation between EZH2 and GLS expression in colorectal cancer tissues. These findings further confirmed the importance of heterogeneity, provided an explanation for the clinical tolerance of cancer cells to EZH2 inhibitors from the perspective of metabolism, and proposed the possibility of combining EZH2 inhibitors and glutamine metabolism inhibitors for the treatment of cancer.

Long Non-coding RNA Small Nucleolar RNA Host Gene 14, a Promising Biomarker and Therapeutic Target in Malignancy

Small nucleolar RNA host gene 14 (SNHG14) is a long non-coding RNA found to be overexpressed in various types of cancers. Moreover, the expression level of SNHG14 was closely associated with multiple clinicopathological characteristics such as prognosis, tumor differentiation, TNM stage, and lymph node metastasis. Functionally, gain- and loss-of-function of SNHG14 revealed that overexpressed SNHG14 promoted cancer cell viability, invasion, and migration, whereas its down-regulation produced the opposite effect. Mechanistically, regulating its target gene expression by sponging distinct miRNAs might be the major mechanism underlying the oncogenic functions of SNHG14. Thus, SNHG14 might be a promising prognostic biomarker and therapeutic target for cancers. In this review, we discuss the expression profile, biological function, and molecular mechanisms of SNHG14 in cancers to provide a molecular basis for the clinical utility of SNHG14 in the future.

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.

Surfaceome Profiling of Rhabdomyosarcoma Reveals B7-H3 as a Mediator of Immune Evasion

Novel therapeutic strategies are needed for the treatment of rhabdomyosarcoma (RMS), the most common soft-tissue sarcoma in children. By using a combination of cell surface proteomics and transcriptomic profiling of RMS and normal muscle, we generated a catalog of targetable cell surface proteins enriched in RMS tumors. Among the top candidates, we identified B7-H3 as the major immunoregulatory molecule expressed by RMS tumors. By using a large cohort of tissue specimens, we demonstrated that B7-H3 is expressed in a majority of RMS tumors while not detected in normal human tissues. Through a deconvolution analysis of the RMS tumor RNA-seq data, we showed that B7-H3-rich tumors are enriched in macrophages M1, NK cells, and depleted in CD8⁺-T cells. Furthermore, in vitro functional assays showed that B7-H3 knockout in RMS tumor cells increases T-cell mediated cytotoxicity. Altogether, our study uncovers new potential targets for the treatment of RMS and provides the first biological insights into the role of B7-H3 in RMS biology, paving the way for the development of next-generation immunotherapies.

Hsa_circ_0006232 promotes laryngeal squamous cell cancer progression through FUS-mediated EZH2 stabilization

Laryngeal squamous cell cancer (LSCC) is one of the most common malignant tumors in head and neck tumors. Our previous study has revealed that hsa_circ_0006232 is abnormally expressed in LSCC. This study attempts to verify the biological role of hsa_circ_0006232 in LSCC. We found that compared with human bronchial epithelial cells, hsa_circ_0006232 was highly expressed in human LSCC cells (AMC-HN-8 and TU686). Moreover, hsa_circ_0006232 promoted proliferation, migration and invasion of AMC-HN-8 and TU686 cells. Hsa_circ_0006232 promoted the expression of enhancer of zeste homolog 2 (EZH2) and repressed the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Fused in sarcoma (FUS) interacted with hsa_circ_0006232 and EZH2, and FUS promoted the stabilization of EZH2. Hsa_circ_0006232 inhibited PTEN by promoting FUS expression. Moreover, we constructed a tumor xenograft model by injection of AMC-HN-8 cells with hsa_circ_0006232 knockdown, and we found that hsa_circ_0006232 deficiency decreased tumor growth in mice. Hsa_circ_0006232 silencing repressed EZH2 expression and enhanced PTEN expression in tumor tissues. In conclusion, our data have demonstrated that Hsa_circ_0006232 promotes proliferation, migration and invasion of LSCC cells, and accelerates tumor growth of LSCC through FUS-mediated EZH2 stabilization. Thus, hsa_circ_0006232 may be a novel therapeutic target in LSCC treatment.

Hsa_circ_0026628 promotes the development of colorectal cancer by targeting SP1 to activate the Wnt/β-catenin pathway

Circular RNAs (circRNAs) have been reported to play crucial roles in the progression of various cancers, including colorectal cancer (CRC). SP1 (Sp1 transcription factor) is a well-recognized oncogene in CRC and is deemed to trigger the Wnt/β-catenin pathway. The present study was designed to investigate the role of circRNAs which shared the same pre-mRNA with SP1 in CRC cells. We identified that hsa_circ_0026628 (circ_0026628), a circular RNA that originated from SP1 pre-mRNA, was upregulated in CRC cells. Sanger sequencing and agarose gel electrophoresis verified the circular characteristic of circ_0026628. Functional assays including CCK-8, colony formation, transwell, immunofluorescence staining, and sphere formation assay revealed the function of circ_0026628. RNA pull-down and mass spectrometry disclosed the proteins interacting with circ_0026628. Mechanistic assays including RIP, RNA pull-down, CoIP, ChIP, and luciferase reporter assays demonstrated the interplays between molecules. The results depicted that circ_0026628 functioned as a contributor to CRC cell proliferation, migration, EMT, and stemness. Mechanistically, circ_0026628 served as the endogenous sponge of miR-346 and FUS to elevate SP1 expression at the post-transcriptional level, thus strengthening the interaction between SP1 and β-catenin to activate the Wnt/β-catenin pathway. In turn, the downstream gene of Wnt/β-catenin signaling, SOX2 (SRY-box transcription factor 2), transcriptionally activated SP1 and therefore boosted circ_0026628 level. On the whole, SOX2-induced circ_0026628 sponged miR-346 and recruited FUS protein to augment SP1, triggering the downstream Wnt/β-catenin pathway to facilitate CRC progression.

Keep your eyes peeled for long noncoding RNAs: Explaining their boundless role in cancer metastasis, drug resistance, and clinical application

Cancer metastasis and drug resistance are two major obstacles in the treatment of cancer and therefore, the leading cause of cancer-associated mortalities worldwide. Hence, an in-depth understanding of these processes and identification of the underlying key players could help design a better therapeutic regimen to treat cancer. Earlier thought to be merely transcriptional junk and having passive or secondary function, recent advances in the genomic research have unravelled that long noncoding RNAs (lncRNAs) play pivotal roles in diverse physiological as well as pathological processes including cancer metastasis and drug resistance. LncRNAs can regulate various steps of the complex metastatic cascade such as epithelial-mesenchymal transition (EMT), invasion, migration and metastatic colonization, and also affect the sensitivity of cancer cells to various chemotherapeutic drugs. A substantial body of literature for more than a decade of research evince that lncRNAs can regulate gene expression at different levels such as epigenetic, transcriptional, posttranscriptional, translational and posttranslational levels, depending on their subcellular localization and through their ability to interact with DNA, RNA and proteins. In this review, we mainly focus on how lncRNAs affect cancer metastasis by modulating expression of key metastasis-associated genes at various levels of gene regulation. We also discuss how lncRNAs confer cancer cells either sensitivity or resistance to various chemo-therapeutic drugs via different mechanisms. Finally, we highlight the immense potential of lncRNAs as prognostic and diagnostic biomarkers as well as therapeutic targets in cancer.

lncRNA SNHG14 promotes the proliferation, migration, and invasion of thyroid tumour cells by regulating miR-93-5p

Long non-coding RNAs (lncRNAs) exert vital functions in the occurrence and development of various tumours. The aim of this study was to examine the regulatory effect and underlying molecular mechanism of lncRNA small nucleolar RNA host gene 14 (SNHG14) on the proliferation, invasion and migration of thyroid tumour cells. The expression of SNHG14 in thyroid tumour cell lines was determined using qRT-PCR. CCK-8 and western blot were used to detect the effects of SNHG14 on proliferation and apoptosis of thyroid tumour cells. The effect of SNHG14 on the migration and invasion of thyroid tumour cells was analyzed using immunofluorescence, wound-healing and transwell assays. A targeting relationship between SNHG14 and miR-93-5p was determined using bioinformatics software and luciferase reporter assays. In addition, CCK-8, immunofluorescence, wound-healing and transwell assays were applied to demonstrate that SNHG14 promoted the proliferation, migration and invasion of thyroid tumour cells by targeting miR-93-5p. The biological function of SNHG14 in vivo was explored through a xenograft model and immunohistochemistry. SNHG14 was upregulated in thyroid tumour cells compared with normal cells. Downregulation of SNHG14 effectively reduced the proliferation, migration and invasion of TPC-1 cells, and induced cell apoptosis. Moreover, SNHG14 directly targeted miR-93-5p and there was a negative correlation between them. Further functional experiments illustrated that miR-93-5p overexpression dramatically reversed the promoting role of SNHG14 in proliferation, migration and invasion of TPC-1 cells. Our results demonstrated that SNHG14 promotes the proliferation, invasion and migration of thyroid tumour cells by downregulating miR-93-5p.

RAMS11 promotes CRC through mTOR-dependent inhibition of autophagy, suppression of apoptosis, and promotion of epithelial-mesenchymal transition

BACKGROUND

Long non-coding RNAs (lncRNAs), a class of non-coding RNAs (ncRNAs) associated with diverse biological processes of cells. Over the past decades, cumulating research evidences revealed that abnormal expressions of lncRNAs are associated with colorectal cancer (CRC) initiation, progression, metastasis, and resistance to therapies. Moreover, their usefulness as candidate biomarkers for CRC diagnosis and prognosis are well evident throughout previous literature. In the current study, we examined the role and molecular mechanisms of newly identified lncRNA named RNA associated with metastasis-11 (RAMS11) in CRC development.

METHODS

The expression of RAMS11 in CRC cell lines DLD-1, HT-29, HCT-116, and SW480 and colon normal cells CCD-112-CoN were evaluated by quantitative RT-qPCR. The results showed that the RAMS11 is significantly upregulated in CRC cell lines compared to the normal cells. The CCK-8 proliferation assay, colony formation assay, and migration assay were performed to evaluate the biological and physiological functions of RAMS11 in vitro. To decipher the molecular mechanisms of RAMS11 medicated CRC progression, we further performed western blot analysis of the key pathway proteins (e.g., AMPK, AKT, and mTOR).

RESULTS

Our results revealed that higher expression of RAMS11 is associated with increased CRC proliferation, migration, and development of metastasis. Knockdown of RAMS11 induced autophagy, apoptosis along with reduction of epithelial-mesenchymal transition (EMT) suggesting that RAMS11 is involved in CRC progression. The molecular mechanisms of RAMS11 indicated that knockdown of RAMS11 significantly inhibited CRC carcinogenesis through mTOR-dependent autophagy induction.

CONCLUSIONS

In sum, our results suggested that RAMS11 is an important oncogene in CRC pathogenesis. Targeting RAMS11 could be a potential therapeutic strategy for CRC management.

Crystal structure of clinically reported mutations Gly656Arg, Gly656Glu and Asp751His identified in the kinase domain of EphA7

Erythropoietin producing hepatocellular (Eph) forms the largest family of receptor tyrosine kinases (RTK). As a family, Eph regulates physiological events such as cell-cell interaction, cell migration, and adhesion. The Kinase domain is the catalytic core of the Eph receptor and is highly conserved sequentially. EphA7 has been recently regarded as a cancer driver gene and comprises several clinically important mutations. Three of the EphA7 mutations Gly656Glu, Gly656Arg, and Asp751His, present in the kinase domain, are predicted to be highly pathogenic. Furthermore, Gly656Glu and Gly656Arg are reported to be hotspot mutations. Considering the importance of mutations, crystals structure of EphA7 Gly656Glu, Gly656Arg, and Asp751His mutants has been explored. Changes in folding pattern and intramolecular interactions were observed in mutant structures. Secondary structural changes were observed in the hinge region of EphA7 Gly656Arg and Asp751His structure, affecting the transition of kinase domain between open and closed conformations. EphA7 Asp751His mutant structure shows a distorted nucleotide-binding groove. Differences were observed in hydrogen bonding and hydrophobic interactions between the catalytic and highly conserved DFG motif in the EphA7 mutants, which may influence the catalytic activity of kinase domain.

LncRNA SNHG14 promotes cell proliferation and invasion in colorectal cancer through modulating miR-519b-3p/DDX5 axis

Numbers of studies suggest that long non-coding RNAs (lncRNAs) exert an important role in cancer progression. It is reported that lncRNA SNHG14 (SNHG14) promotes cell proliferation and invasion in many cancers. However, the underlying molecular mechanism of SNHG14 in colorectal cancer (CRC) remains unclear. In our study, we found that SNHG14 is highly expressed in CRC tissues and cells, especially in SW480 and HT-29 cells. In addition, sh-SNHG14 inhibits cell proliferation, cell migration and invasion, promotes cell apoptosis in CRC cell lines. Furthermore, we found that SNHG14 functions as a sponge for miR-519b-3p, while the DEAD box protein 5 (DDX5) is a downstream target gene of miR-519b-3p, and the functions of miR-519b-3p inhibitors on the CRC progression could be rescued by downregulation of DDX5. Our findings suggest that SNHG14 promotes the CRC progression by miR-519b-3p/DDX5 axis, implying the promising therapeutic target of SNHG4 for CRC patients.

Small nucleolar RNA host genes promoting epithelial-mesenchymal transition lead cancer progression and metastasis

The small nucleolar RNA host genes (SNHGs) belong to the long non-coding RNAs and are reported to be able to influence all three levels of cellular information-bearing molecules, that is, DNA, RNA, and proteins, resulting in the generation of complex phenomena. As the host genes of the small nucleolar RNAs (snoRNAs), they are commonly localized in the nucleolus, where they exert multiple regulatory functions orchestrating cellular homeostasis and differentiation as well as metastasis and chemoresistance. Indeed, worldwide literature has reported their involvement in the epithelial-mesenchymal transition (EMT) of different histotypes of cancer, being able to exploit peculiar features, for example, the possibility to act both in the nucleus and the cytoplasm. Moreover, SNHGs regulation is a fundamental topic to better understand their role in tumor progression albeit such mechanism is still debated. Here, we reviewed the biological functions of SNHGs in particular in the EMT process and discussed the perspectives for new cancer therapies.

LncRNA PART1 promotes cell proliferation and inhibits apoptosis of oral squamous cell carcinoma by blocking EZH2 degradation

Long noncoding RNAs (lncRNAs) have been considered as novel regulators in oral squamous cell carcinoma (OSCC). Enhancer of zeste homolog 2 (EZH2) can act as an oncogene in OSCC. This study intended to investigate whether lncRNA PART1 can exert its role in OSCC by regulating EZH2. The expression of PART1 in OSCC samples, tumors tissues, or OSCC cell lines was detected by qRT-PCR. The proliferation and apoptosis of OSCC cells were detected by CCK-8 and flow cytometry assays, respectively. The expression of PART1 and EZH2 were highly expressed in clinical OSCC tumors and cell lines. The expression level of PART1 was positively correlated to the size, clinical stage, and node metastasis of OSCC patients. Functionally, PART1 knockdown inhibited proliferation and facilitated apoptosis of OSCC cells. Mechanically, FUS interacted with PART1 and EZH2. Additionally, PART1 knockdown reduced the mRNA expression of EZH2, which was offset by FUS overexpression. The overexpression of FUS abrogated the effects of PART1 silence on proliferation and apoptosis of OSCC cells. The in vivo experiment revealed that PART1 knockdown inhibited tumor growth of OSCC cells in nude mice. This study indicated that PART1 exerts a carcinogenic role in OSCC by enhancing the stability of EZH2 protein.

Progress in research of EZH2 in digestive system tumors

EZH2 is a key member of the PcG protein family and a subunit of catalytic activity in the PRC2 complex. It has histone methylation transferase activity and plays an important role in epigenetic modification. A large number of studies have shown that it is closely related to the occurrence, development, and prognosis of various digestive system tumors and is highly expressed in tumor tissues, such as gastric cancer, liver cancer, colorectal cancer, pancreatic cancer, and gallbladder cancer. In this paper, we review the biological characteristics of EZH2d , its role in digestive system tumors, and the prospect of targeted therapy for EZH2.

The Emerging Landscape of Long Non-Coding RNAs in Colorectal Cancer Metastasis

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers, with extremely high rates of morbidity and mortality. The main cause of death in CRC is distant metastasis; it affects patient prognosis and survival and is one of the key challenges in the treatment of CRC. Long non-coding RNAs (lncRNAs) are a group of non-coding RNA molecules with more than 200 nucleotides. Abnormal lncRNA expression is closely related to the occurrence and progression of several diseases, including cancer. Recent studies have shown that numerous lncRNAs play pivotal roles in the CRC metastasis, and reversing the expression of these lncRNAs through artificial means can reduce the malignant phenotype of metastatic CRC to some extent. This review summarizes the major mechanisms of lncRNAs in CRC metastasis and proposes lncRNAs as potential therapeutic targets for CRC and molecular markers for early diagnosis.

An edge-based statistical analysis of long non-coding RNA expression profiles reveals a negative association between Parkinson's disease and colon cancer

BACKGROUND

Colon cancer (CC) is one of the most common malignant tumors, while Parkinson's disease (PD) is the second most common neurodegenerative disorder. Recent accumulating evidence indicates that these two diseases are associated with each other. Also, from the perspective of long non-coding RNAs, some well-known genes such as H19 and PVT1 can link these two diseases together. Several studies have shown that patients with PD had a decreased risk of developing CC compared with patients without PD. However, controversies surround the relationship between PD and CC, and to date, no concordant conclusion has been drawn.

METHODS

In this study, we aimed to assess the association between these two diseases based on lncRNA-to-lncRNA interactions. Motivated by the weighted gene co-expression network analysis method, a customized procedure was proposed and used to identify differentially correlated edges (DCEs) in the respective interaction networks for PD and CC and explore how these two diseases are linked.

RESULTS

Of the two sets of DCEs for PD and CC, 16 pairs overlapped. Among them, 15 edges had opposite signs, with positive signs for CC indicating a gain of connectivity, whereas negative signs for PD indicating a loss of connectivity.

CONCLUSIONS

By using the lncRNA expression profiles, and a customized procedure, an answer to the question about how PD and CC are associated is provided.

Transcriptome Based System Biology Exploration Reveals Homogeneous Tumorigenicity of Alimentary Tract Malignancy

Malignancies of alimentary tract include esophageal carcinoma (ESCA), stomach adenocarcinoma (STAD), colon adenocarcinoma (COAD), and rectum adenocarcinoma (READ). Despite of their similarities in cancer development and progression, there are numerous researches concentrating on single tumor but relatively little on their common mechanisms. Our study explored the transcriptomic data of digestive tract cancers from The Cancer Genome Atlas database, yielding their common differentially expressed genes including 1,700 mRNAs, 29 miRNAs, and 362 long non-coding RNAs (lncRNAs). There were 12 mRNAs, 5 miRNAs, and 16 lncRNAs in the core competitive endogenous RNAs network by RNA-RNA interactions, highlighting the prognostic nodes of SERPINE1, hsa-mir-145, and SNHG1. In addition, the weighted gene co-expression network analysis (WGCNA) illustrated 20 gene modules associated with clinical traits. By taking intersections of modules related to the same trait, we got 67 common genes shared by ESCA and READ and screened 5 hub genes, including ADCY6, CXCL3, NPBWR1, TAS2R38, and PTGDR2. In conclusion, the present study found that SERPINE1/has-mir-145/SNHG1 axis acted as promising targets and the hub genes reasoned the similarity between ESCA and READ, which revealed the homogeneous tumorigenicity of digestive tract cancers at the transcriptome level and led to further comprehension and therapeutics for digestive tract cancers.

Long noncoding RNA TPT1-AS1 promotes the progression and metastasis of colorectal cancer by upregulating the TPT1-mediated FAK and JAK-STAT3 signalling pathways

Tumour protein translationally controlled 1 (TPT1) antisense RNA 1 (TPT1-AS1) is known to be involved in the development and metastasis of cervical and ovarian cancers; however, its biological role in colorectal cancer (CRC) remains unknown. This study aimed to determine the function and mechanism of action of TPT1-AS1 in the progression and metastasis of CRC. Elevated TPT1-AS1 levels were observed in CRC tissues. Furthermore, the high expression levels were found to be correlated with unfavourable clinicopathological characteristics in CRC. Cell function experiments demonstrated that TPT1-AS1 depletion impeded cell proliferation, migration and invasion and enhanced cell adhesion; it also attenuated tumorigenesis and metastasis in vivo. Additionally, TPT1-AS1 was predominately located in the nuclei of the cells and could upregulate the expression of TPT1 by recruiting mixed lineage leukaemia protein-1 (MLL1), which increased the trimethylation of H3K4 me3 in the TPT1 promoter region and subsequently activated FAK and JAK-STAT3 signalling cascades. The inhibition of FAK activation by PF573228 significantly attenuated the oncogenic effect of TPT1-AS1. These findings indicated that TPT1-AS1 promoted tumour progression and metastasis in CRC by upregulating TPT1 levels and activating the FAK and JAK-STAT3 signalling pathways. Thus, TPT1-AS1 may be considered as a potential therapeutic target for CRC.

Identification of an RNA binding protein-related gene signature in hepatocellular carcinoma patients

Background

Hepatocellular carcinoma (HCC) is a common malignant primary cancer with high mortality. Previous studies have demonstrated that RNA binding proteins (RBPs) are involved in the biological processes of cancers, including hepatocellular cancer.

Methods

In this study, we aimed to identify the clinical value of RNA-binding proteins for hepatocellular carcinoma. We obtained gene expression and clinical data of hepatocellular carcinoma patients from the TCGA and ICGC databases. The prognostic value of RBP-related genes in patients with hepatocellular carcinoma and their function were studied by comprehensive bioinformatics analyses. The gene signature of SMG5, EZH2, FBLL1, ZNF239, and IGF2BP3 was generated by univariate and multivariate Cox regression and LASSO regression analyses. We built and verified a prognostic nomogram based on RBP-related genes. The gene signature was validated by the ICGC database. The expression of RBP-related genes was validated by the Oncomine database, the Human Protein Atlas and Kaplan–Meier plotter.

Result

Most RBP-related genes were significantly different in cancer and normal tissues. The survival of patients in the different groups was significantly different. The gene signature showed good performance for predicting the survival of HCC patients by having a better area under the receiver operating characteristic curve than other clinicopathological parameters.

Conclusion

Gene signatures based on RNA-binding proteins can be independent risk factors for hepatocellular carcinoma patients.

LncRNA STXBP5-AS1 suppresses stem cell-like properties of pancreatic cancer by epigenetically inhibiting neighboring androglobin gene expression

Previous studies suggest the tumor suppressor role of long non-coding RNA (lncRNA) STXBP5-AS1 in cervical and gastric cancer, but its expression pattern and functional mechanism are still elusive in pancreatic cancer (PC). Relative expression of STXBP5-AS1 in PC both in vivo and in vitro was analyzed by real-time PCR. IC₅₀ of Gemcitabine was determined by the MTT assay. Cell proliferation in response to drug treatment was investigated by colony formation assay. Cell apoptosis was measured by both caspase-3 activity and Annexin V/PI staining. Cell invasion capacity was scored by the transwell assay in vitro, and lung metastasis was examined with the tail vein injection assay. Cell stemness was determined in vitro by sphere formation and marker profiling, respectively, and in vivo by limited dilution of xenograft tumor incidence. Subcellular localization of STXBP5-AS1 was analyzed with fractionation PCR. Association between STXBP5-AS1 and EZH2 was investigated by RNA-immunoprecipitation. The binding of EZH2 on ADGB promoter was analyzed by chromatin immunoprecipitation. The methylation was quantified by bisulfite sequencing. We showed downregulation of STXBP5-AS1 in PC associated with poor prognosis. Ectopic STXBP5-AS1 inhibited chemoresistance and metastasis of PC cells. In addition, STXBP5-AS1 compromised stemness of PC cells. Mechanistically, STXBP5-AS1 potently recruited EZH2 and epigenetically regulated neighboring ADGB transcription, which predominantly mediated the inhibitory effects of STXBP5-AS1 on stem cell-like properties of PC cells. Our study highlights the importance of the STXBP5-EZH2-ADGB axis in chemoresistance and stem cell-like properties of PC.

LUCAT1 Epigenetically Downregulates the Tumor Suppressor Genes CXXC4 and SFRP2 in Gastric Cancer

PURPOSE

The mechanisms of Wnt/β-catenin pathway signaling and abnormal expression of tumor suppressor genes is not well known in gastric cancer (GC). Long non-coding RNA (lncRNA) has recently been identified as a possible link therein. In this study, we investigated the role of lung cancer associated transcript 1 (LUCAT1) in GC.

MATERIALS AND METHODS

The expression of LUCAT1 in GC cell lines and 100 tissue samples was examined by qRT-PCR. Two different siRNAs were used for knockdown of LUCAT1 expression. Cell viability was assessed by MTT assay. To analyze metastasis, scratch wound-healing assay, a Matrigel invasion assay, and colony formation assay were performed. Apoptosis was analyzed by PI/Annexin-V staining. To check the methylation status in tumor suppressor genes, methylation-specific PCR was carried out. Western blot was performed to detect epithelial-mesenchymal transition and apoptosis markers upon silencing of LUCAT1 (siLUCAT1).

RESULTS

LUCAT1 expression in GC cell lines and tissues was significantly elevated, compared to that in normal gastric cells and adjacent non-tumor tissues (p<0.001). Two different siRNAs for LUCAT1 reduced cell proliferation, invasion, and migration, compared to siCT (p<0.05), and these reductions were restored by pcDNA-LUCAT1 (p<0.05). siLUCAT1 elicited upregulation of the expression of CXXC4 and SFRP2. The expression of H3K27me3 was reduced by siLUCAT1, and this reduction was correlated with methylation of CXXC4 and SFRP2. Inhibition of LUCAT1 up-regulated EZH2 expression and resulted in demethylation of CXXC4 and SFRP2 through the Wnt/β-catenin signaling pathway.

CONCLUSION

We concluded that LUCAT1 induces methylation of CXXC4 and SFRP2, thereby regulating Wnt/β-catenin signaling in GC.

The oncogenic role of LncRNA FAM83C-AS1 in colorectal cancer development by epigenetically inhibits SEMA3F via stabilizing EZH2

Inactivation of Semaphorin 3F (SEMA3F) is involved in colorectal cancer development. However, the mechanism by which SEMA3F is regulated remains elusive. Deregulation of lncRNAs have been implicated in multiple human malignancies, including colorectal cancer (CRC). To date, it is still unclear whether and how lncRNA regulates SEMA3F expression and mediates CRC progression. Here we identify the oncogenic role of lncRNA FAM83C antisense RNA 1 (FAM83C-AS1) in CRC. FAM83C-AS1 is upregulated in tumor tissues and cells of CRC, which is negatively correlated with SEMA3F expression. Reciprocally, knockdown of FAM83C-AS1 exhibits inhibitory effects on the malignant transformation of CRC. Moreover, our data uncover that FAM83C-AS1 enhances methylation of SEMA3F promoter H3K27me3 via upregulating methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). Specifically, FAM83C-AS1 stabilizes EZH2 protein through recruiting the zinc finger RANBP2-type containing 1 (ZRANB1). Both in vitro and in vivo rescue assays exhibit that SEMA3F is dispensable for the tumor-promoting effects of FAM83C-AS1 on CRC progression. Our data thus demonstrate that the epigenetic role of FAM83C-AS1 in suppression of SEMA3F expression through stabilization of EZH2 to drive CRC progression, which may be conducive to discovering novel therapeutic targets for the treatment of CRC.

lncRNA DUXAP8 Facilitates Multiple Malignant Phenotypes and Resistance to PARP Inhibitor in HCC via Upregulating FOXM1

In this study, we examined the clinical significance and molecular mechanisms of a long non-coding RNA (lncRNA), double homeobox A pseudogene 8 (DUXAP8) in hepatocellular carcinoma (HCC). DUXAP8 expression was compared using quantitative real-time PCR in HCC versus adjacent tissues and in HCC cell lines versus normal hepatic epithelial cells. The correlations between DUXAP8 level and clinicopathological features were analyzed. Assays including MTT, colony-forming analysis, Transwell assay, western blot, xenograft formation, experimental metastasis, luciferase assay, RNA pull-down, and RNA immunoprecipitation were used to examine DUXAP8-induced malignant phenotypes, its regulation on forkhead box protein M1 (FOXM1), and the importance of FOXM1 in mediating DUXAP8 phenotypes. Our results showed that DUXAP8 was significantly upregulated in HCC tissues or cell lines associated with tumors of advanced grades, tumors that were positive for lymph node metastasis, and patients with poor overall survival. DUAXP8 was essential in maintaining multiple malignant phenotypes (including resistance to olaparib) both in vitro and in vivo. Mechanistically, DUXAP8 upregulated FOXM1 expression by sponging miR-485-5p and interacting with the RNA-binding protein Fused in Sarcoma (FUS). Functionally, FOXM1 essentially mediated the oncogenic phenotypes of DUXAP8. Collectively, DUXAP8 acts through two distinct mechanisms to upregulate FOXM1 and becomes a pleotropic oncogenic lncRNA in HCC.

Long Non-Coding RNA SNHG14 Regulates SPIN1 Expression to Accelerate Tumor Progression in Non-Small Cell Lung Cancer by Sponging miR-382-5p

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most common type of lung carcinoma. Long non-coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) was identified to participate in tumor progression. However, the mechanism and functions of SNHG14 were rarely reported in NSCLC progression.

METHODS

The relative gene expression was tested by qRT-PCR. Cell viability, apoptosis, migration and invasion were measured by MTT assay, flow cytometry, and transwell migration and invasion assays, respectively. The interactions between miR-382-5p and SNHG14 or SPIN1 were predicted by starBase and confirmed by the dual-luciferase reporter assay and RNA pull-down assay. The protein level of SPIN1 was evaluated by Western blot assay.

RESULTS

The levels of SNHG14 and SPIN1 were significantly increased, while the level of miR-382-5p was apparently reduced in NSCLC tissues and cells. SNHG14 was verified to sponge miR-382-5p and SPIN1 was identified as a direct target of miR-382-5p. SNHG14 depletion repressed cell viability, migration and invasion, but induced the apoptotic rate by targeting miR-382-5p. miR-382-5p overexpression blocked cell viability, metastasis and promoted cell apoptosis by regulating SPIN1. SNHG14 silencing down-regulated SPIN1 expression by sponging miR-382-5p.

CONCLUSION

SNHG14 facilitated NSCLC progression by regulating SPIN1 expression via targeting miR-382-5p.