Long non-coding RNA MALAT1 regulates oxaliplatin-resistance via miR-324-3p/ADAM17 axis in colorectal cancer cells

Silencing of LINC01278 promotes sensitivity of non-small cell lung cancer cells to osimertinib by targeting miR-324-3p/ZFX axis

Osimertinib has been demonstrated to be effective for improving the prognosis of patients with epidermal growth factor receptor mutation-positive lung cancer. However, osimertinib resistance inevitably emerges throughout the treatment course. This study explored the function and mechanism of long noncoding RNA LINC01278 in osimertinib-resistant NSCLC cells. Osimertinib-resistant non-small cell lung cancer (NSCLC) cells were established by treating PC9 and HCC827 cells with increasing doses of osimertinib for over 6 months. LINC01278 expression in parental and drug-resistant cells (PC9-OR and HCC827-OR) was measured by polymerase chain reaction. Cell counting kit 8 assays were used to examine cell viability and half-maximal inhibitory concentration values. The effects of LINC01278 knockdown on cell proliferation and apoptosis were measured by colony formation assays and flow cytometry. A luciferase reporter assay was performed to verify the interaction between LINC01278 and miR-324-3p or the binding ability between miR-324-3p and ZFX. Protein levels of ZFX and apoptotic markers in NSCLC cells were measured by western blotting. As shown by experimental results, LINC01278 was highly expressed in osimertinib-resistant NSCLC cells compared to its expression in parental cells. The silencing of LINC01278 improved the sensitivity of drug-resistant cells towards osimertinib. LINC1278 depletion inhibited osimertinib-resistant cell proliferation while promoting cell apoptosis. LINC01278 interacted with miR-324-3p to regulate ZFX expression. ZFX could be targeted by miR-324-3p in PC9-OR and HCC827-OR cells. ZFX overexpression counteracted the suppressive impact of LINC01278 silencing on the malignant behavior of PC9-OR and HCC827-OR cells. In conclusion, LINC01278 knockdown alleviates osimertinib resistance of NSCLC cells by regulating downstream miR-324-3p and ZFX.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-024-00673-8.

LncRNA SNHG16 Drives PD-L1-Mediated Immune Escape in Colorectal Cancer through Regulating miR-324-3p/ELK4 Signaling

Colorectal cancer (CRC) is a common malignancy that claims the life of many patients. Nucleolar RNA host gene 16 (SNHG16) has been identified as an oncogene in CRC development. However, the role and mechanism of SNHG16 in CRC remain unclear. A total of 27 cases of CRC tumor tissues and adjacent tissues were collected to investigate the expression and correlation among SNHG16, miR-324-3p, ELK4 and PD-L1 using qRT-PCR, western blot and Pearson analysis. Cell proliferation, migration and invasion abilities were determined using CCK-8 and transwell assays. The cytotoxicity of CD8 + T cells and the apoptosis of CD8+ T cells was evaluated by LDH assay and flow cytometry, respectively. Dual luciferase assay, RIP and ChIP methods were performed to verify molecular interactions. Our results showed that SNHG16, ELK4 and PD-L1 expression were abnormally elevated and miR-324-3p expression was decreased in tumor tissues from CRC patients and CRC cells. SNHG16 silencing resulted in suppression of cell growth, metastasis, and immune escape of CRC cells, which was reversed by miR-324-3p inhibitor and ELK4 overexpression. Mechanistically, SNHG16 acted as a competitive endogenous RNA to enhance ELK4 expression by sponging miR-324-3p, thereby provoking the transcription of PD-L1. Our results demonstrated that SNHG16 silencing led to the suppression of cell growth, metastasis, and immune escape of CRC cells through mediating miR-324-3p/ELK4/PD-L1 axis, offering promising targets for CRC treatment.

Identification of key lncRNAs associated with oxaliplatin resistance in colorectal cancer cells and isolated exosomes: From In-Silico prediction to In-Vitro validation

One of the critical challenges in managing colorectal cancer (CRC) is the development of oxaliplatin (OXP) resistance. Long non-coding RNAs (lncRNAs) have a crucial role in CRC progression and chemotherapy resistance, with exosomal lncRNAs emerging as potential biomarkers. This study aimed to predict key lncRNAs involved in OXP-resistance using in-silico methods and validate them using RT-qPCR methods in CRC cells and their isolated exosomes. Two public datasets, GSE42387 and GSE119481, were downloaded from the GEO database to identify differentially expressed genes (DEGs) and miRNAs (DEmiRNAs) associated with OXP-resistance in the HCT116 cell line. The analysis of GSE42387 revealed 210 DEGs, and GSE119481 identified 73 DEmiRNAs. A protein-protein interaction (PPI) network analysis of the DEGs identified 133 interconnected genes, from which the top ten genes with the highest degree scores were selected. By intersecting predicted miRNAs targeting these genes with the DEmiRNAs, 38 common miRNAs were found. Subsequently, 224 lncRNAs targeting these common miRNAs were predicted. LncRNA-miRNA-mRNA network were constructed and the top five lncRNAs with the highest degree scores were identified. Analysis using the Kaplan-Meier plotter database revealed that the key lncRNAs NEAT1, OIP5-AS1, and MALAT1 are significantly associated with the overall survival of CRC patients. To validate these lncRNAs, OXP-resistant HCT116 sub-cell line (HCT116/OXR) was developed by exposing parental HCT116 cells to gradually increasing concentrations of OXP. Exosomes derived from both HCT116 and HCT116/OXR cells were isolated and characterized utilizing dynamic light scattering (DLS), transmission electron microscopy (TEM), and Western blotting. RT-qPCR confirmed elevated levels of NEAT1, OIP5-AS1, and MALAT1 in HCT116/OXR cells and their exosomes compared to parental HCT116 cells and their exosomes. This study concludes that NEAT1, OIP5-AS1, and MALAT1 are associated with the OXP-resistance in CRC. The high levels of these lncRNAs in exosomes of resistant cells suggest their involvement in intercellular communication and resistance propagation. This positioning makes them promising biomarkers for OXP-resistance in CRC.

Relationship between lncRNA MALAT1 and Chemo-radiotherapy Resistance of Cancer Cells: Uncovered Truths

The advancement of novel technologies, coupled with bioinformatics, has led to the discovery of additional genes, such as long noncoding RNAs (lncRNAs), that are associated with drug resistance. LncRNAs are composed of over 200 nucleotides and do not possess any protein coding function. These lncRNAs exhibit lower conservation across species, are typically expressed at low levels, and often display high specificity towards specific tissues and developmental stages. The LncRNA MALAT1 plays crucial regulatory roles in various aspects of genome function, encompassing gene transcription, splicing, and epigenetics. Additionally, it is involved in biological processes related to the cell cycle, cell differentiation, development, and pluripotency. Recently, MALAT1 has emerged as a novel mechanism contributing to drug resistance or sensitivity, attracting significant attention in the field of cancer research. This review aims to explore the mechanisms through which MALAT1 confers resistance to chemotherapy and radiotherapy in cancer cells.

Beyond the genome: MALAT1's role in advancing urologic cancer care

Urologic cancers (UCs), which include bladder, kidney, and prostate tumors, account for almost a quarter of all malignancies. Long non-coding RNAs (lncRNAs) are tissue-specific RNAs that influence cell growth, death, and division. LncRNAs are dysregulated in UCs, and their abnormal expression may allow them to be used in cancer detection, outlook, and therapy. With the identification of several novel lncRNAs and significant exploration of their functions in various illnesses, particularly cancer, the study of lncRNAs has evolved into a new obsession. MALAT1 is a flexible tumor regulator implicated in an array of biological activities and disorders, resulting in an important research issue. MALAT1 appears as a hotspot, having been linked to the dysregulation of cell communication, and is intimately linked to cancer genesis, advancement, and response to treatment. MALAT1 additionally operates as a competitive endogenous RNA, binding to microRNAs and resuming downstream mRNA transcription and operation. This regulatory system influences cell growth, apoptosis, motility, penetration, and cell cycle pausing. MALAT1's evaluation and prognosis significance are highlighted, with a thorough review of its manifestation levels in several UC situations and its association with clinicopathological markers. The investigation highlights MALAT1's adaptability as a possible treatment target, providing fresh ways for therapy in UCs as we integrate existing information The article not only gathers current knowledge on MALAT1's activities but also lays the groundwork for revolutionary advances in the treatment of UCs.

Competitive endogenous RNA networks: Decoding the role of long non-coding RNAs and circular RNAs in colorectal cancer chemoresistance

Colorectal cancer (CRC) is recognized as one of the most common gastrointestinal malignancies across the globe. Despite significant progress in designing novel treatments for CRC, there is a pressing need for more effective therapeutic approaches. Unfortunately, many patients undergoing chemotherapy develop drug resistance, posing a significant challenge for cancer treatment. Non-coding RNAs (ncRNAs) have been found to play crucial roles in CRC development and its response to chemotherapy. However, there are still gaps in our understanding of interactions among various ncRNAs, such as long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs). These ncRNAs can act as either oncogenes or tumour suppressors, affecting numerous biological functions in different cancers including CRC. A class of ncRNA molecules known as competitive endogenous RNAs (ceRNAs) has emerged as a key player in various cellular processes. These molecules form networks through lncRNA/miRNA/mRNA and circRNA/miRNA/mRNA interactions. In CRC, dysregulation of ceRNA networks has been observed across various cellular processes, including proliferation, apoptosis and angiogenesis. These dysregulations are believed to play a significant role in the progression of CRC and, in certain instances, may contribute to the development of chemoresistance. Enriching our knowledge of these dysregulations holds promise for advancing the field of diagnostic and therapeutic modalities for CRC. In this review, we discuss lncRNA- and circRNA-associated ceRNA networks implicated in the emergence and advancement of drug resistance in colorectal carcinogenesis.

Construction and identification of lncRNA/circRNA-coregulated ceRNA networks in gemcitabine-resistant bladder carcinoma

OBJECTIVES

To explore the regulatory networks that underlie the development of chemoresistance in bladder cancer.

METHODS

We analyzed profiles of differentially expressed long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), microRNAs (miRNAs) and messenger RNA (mRNAs) in gemcitabine-resistant/sensitive bladder cancer cells using next-generation sequencing data.

RESULTS

Hundreds of differentially expressed lncRNAs and miRNAs and thousands of circRNAs and mRNAs were identified. Bioinformatics analysis revealed the chromosomal localizations, classification and coexpression of mRNAs, as well as candidates for cis and trans regulation by lncRNAs. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis of differentially expressed mRNAs and circRNAs indicated important functional roles of coregulated RNAs, thus establishing competing endogenous RNA (ceRNA) and protein-protein interactions networks that may underlie chemoresistance in bladder cancer. We demonstrated that lncRNA LINP1 can act as a ceRNA by inhibiting miR-193a-5p to increase TP73 expression; and that lncRNA ESRG and hsa_circ_0075881 can simultaneously bind miR-324-3p to increase ST6GAL1 expression. Modulation of ceRNA network components using ablation and overexpression approaches contributed to gemcitabine resistance in bladder cancer cells.

CONCLUSIONS

These results elucidate mechanisms by which lncRNAs and circRNAs coregulate the development of bladder cancer cell resistance to gemcitabine, thus laying the foundation for future research to identify biomarkers and disease targets.

MALAT1 in Liquid Biopsy: The Diagnostic and Prognostic Promise for Colorectal Cancer and Adenomas?

Introduction

The development of colorectal cancer (CRC) is a multistep process accompanied by the accumulation of mutations that start from specific precancerous lesion - colorectal adenomas (CA). CRC incidence and mortality can be reduced by the early identification of these neoplasm. Colonoscopy is the most widely used screening method for CRC identification. Nowadays, clinical research interest is shifting to the use of liquid biopsy that may help with the early diagnosis of CA and CRC. In our previous study, we identified long non-coding RNA MALAT1 gene amplification associated with the development of CA.

Methods

This study aimed to describe the potential of MALAT1 expression levels in the adenoma tissue of patients used in the previous study by real-time qPCR. Furthermore, we analysed the plasma samples of an independent group of patients with CA (n=97), CRC (n=101), and cancer-free individuals (CFI, n=48).

Results

There was no difference in the MALAT1 expression level between CA patients with or without MALAT1 amplification. However, the plasma MALAT1 expression levels were significantly upregulated in patients with CRC and CA compared to CFI (for both p<0.001). Moreover, a correlation between MALAT1 expression and histological types of adenomas was identified- high-CRC-risk adenomas also displayed the highest MALAT1 expression levels. Furthermore, in CRC patients, MALAT1 levels were associated with a response to therapy.

Conclusion

MALAT1 expression levels could serve as a promising circulating biomarker for early CA and CRC diagnosis, and even as a predictor of therapy response in CRC patients.

The non-coding competing endogenous RNAs in acute myeloid leukemia: biological and clinical implications

Acute myeloid leukemia (AML) is a hematologic carcinoma that has seen a considerable improvement in patient prognosis because of genetic diagnostics and molecularly-targeted therapies. Nevertheless, recurrence and drug resistance remain significant obstacles to leukemia treatment. It is critical to investigate the underlying molecular mechanisms and find solutions. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), circular RNAs, long non-coding RNAs, and pseudogenes, have been found to be crucial components in driving cancer. The competing endogenous RNA (ceRNA) mechanism has expanded the complexity of miRNA-mediated gene regulation. A great deal of literature has shown that ncRNAs are essential to the biological functions of the ceRNA network (ceRNET). NcRNAs can compete for the same miRNA response elements to influence miRNA-target RNA interactions. Recent evidence suggests that ceRNA might be a potential biomarker and therapeutic strategy. So far, however, there have been no comprehensive studies on ceRNET about AML. What is not yet clear is the clinical application of ceRNA in AML. This study attempts to summarize the development of research on the related ceRNAs in AML and the roles of ncRNAs in ceRNET. We also briefly describe the mechanisms of ceRNA and ceRNET. What's more significant is that we explore the clinical value of ceRNAs to provide accurate diagnostic and prognostic biomarkers as well as therapeutic targets. Finally, limitations and prospects are considered.

ADAM17 Confers Temozolomide Resistance in Human Glioblastoma Cells and miR-145 Regulates Its Expression

Glioblastoma (GBM) is a malignant brain tumor, commonly treated with temozolomide (TMZ). Upregulation of A disintegrin and metalloproteinases (ADAMs) is correlated to malignancy; however, whether ADAMs modulate TMZ sensitivity in GBM cells remains unclear. To explore the role of ADAMs in TMZ resistance, we analyzed changes in ADAM expression following TMZ treatment using RNA sequencing and noted that ADAM17 was markedly upregulated. Hence, we established TMZ-resistant cell lines to elucidate the role of ADAM17. Furthermore, we evaluated the impact of ADAM17 knockdown on TMZ sensitivity in vitro and in vivo. Moreover, we predicted microRNAs upstream of ADAM17 and transfected miRNA mimics into cells to verify their effects on TMZ sensitivity. Additionally, the clinical significance of ADAM17 and miRNAs in GBM was analyzed. ADAM17 was upregulated in GBM cells under serum starvation and TMZ treatment and was overexpressed in TMZ-resistant cells. In in vitro and in vivo models, ADAM17 knockdown conferred greater TMZ sensitivity. miR-145 overexpression suppressed ADAM17 and sensitized cells to TMZ. ADAM17 upregulation and miR-145 downregulation in clinical specimens are associated with disease progression and poor prognosis. Thus, miR-145 enhances TMZ sensitivity by inhibiting ADAM17. These findings offer insights into the development of therapeutic approaches to overcome TMZ resistance.

Downregulation of AC092894.1 promotes oxaliplatin resistance in colorectal cancer via the USP3/AR/RASGRP3 axis

BACKGROUND

Oxaliplatin resistance is a complex process and has been one of the most disadvantageous factors and indeed a confrontation in the procedure of colorectal cancer. Recently, long non-coding RNAs (lncRNAs) have emerged as novel molecules for the treatment of chemoresistance, but the specific molecular mechanisms mediated by them are poorly understood.

METHODS

The lncRNAs associated with oxaliplatin resistance were screened by microarray. lncRNA effects on oxaliplatin chemoresistance were then verified by gain- and loss-of-function experiments. Finally, the potential mechanism of AC092894.1 was explored by RNA pull-down, RIP, and Co-IP experiments.

RESULTS

AC092894.1 representation has been demonstrated to be drastically downregulated throughout oxaliplatin-induced drug-resistant CRC cells. In vivo and in vitro experiments revealed that AC092894.1 functions to reverse chemoresistance. Studies on the mechanism suggested that AC092894.1 served as a scaffold molecule that mediated the de-ubiquitination of AR through USP3, thereby increasing the transcription of RASGRP3. Finally, sustained activation of the MAPK signaling pathway induced apoptosis in CRC cells.

CONCLUSIONS

In conclusion, this study identified AC092894.1 as a suppressor of CRC chemoresistance and revealed the idea that targeting the AC092894.1/USP3/AR/RASGRP3 signaling axis is a novel option for the treatment of oxaliplatin resistance.

MicroRNA-324-3p inhibits osteosarcoma progression by suppressing PGAM1-mediated aerobic glycolysis

Osteosarcoma (OS) is the most common primary malignant neoplasm of the bone. Recent studies have indicated that the inhibitory effects of microRNA (miR)-324-3p could affect the development of numerous cancers. However, its biological roles and underlying mechanisms in OS progression remain unexplored. In this study, miR-324-3p expression was markedly reduced in OS cell lines and tissues. Functionally, miR-324-3p overexpression suppressed OS progression and was involved in the Warburg effect. Mechanistically, miR-324-3p negatively regulated phosphoglycerate mutase 1 (PGAM1) expression by targeting its 3'-UTR. Moreover, high expression of PGAM1 promoted OS progression and aerobic glycolysis, which were associated with inferior overall survival in patients with OS. Notably, the tumor suppressor functions of miR-324-3p were partially recovered by PGAM1 overexpression. In summary, the miR-324-3p/PGAM1 axis plays an important role in regulating OS progression by controlling the Warburg effect. Our results provide mechanistic insights into the function of miR-324-3p in glucose metabolism and subsequently on the progression of OS. Targeting the miR-324-3p/PGAM1 axis could be a promising molecular strategy for the treatment of OS.

Emerging roles of non-coding RNAs in colorectal cancer oxaliplatin resistance and liquid biopsy potential

Colorectal cancer (CRC) is one of the most common malignancies of the digestive tract, with the annual incidence and mortality increasing consistently. Oxaliplatin-based chemotherapy is a preferred therapeutic regimen for patients with advanced CRC. However, most patients will inevitably develop resistance to oxaliplatin. Many studies have reported that non-coding RNAs (ncRNAs), such as microRNAs, long non-coding RNAs, and circular RNAs, are extensively involved in cancer progression. Moreover, emerging evidence has revealed that ncRNAs mediate chemoresistance to oxaliplatin by transcriptional and post-transcriptional regulation, and by epigenetic modification. In this review, we summarize the mechanisms by which ncRNAs regulate the initiation and development of CRC chemoresistance to oxaliplatin. Furthermore, we investigate the clinical application of ncRNAs as promising biomarkers for liquid CRC biopsy. This review provides new insights into overcoming oxaliplatin resistance in CRC by targeting ncRNAs.

SIRT1 enhances oxaliplatin resistance in colorectal cancer through microRNA-20b-3p/DEPDC1 axis

Oxaliplatin (L-OHP) is a standard treatment drug for colorectal cancer (CRC), but acquired drug resistance limits the outcome of patients. We investigated the involvement of sirtuin 1 (SIRT1) in L-OHP resistance in the setting of CRC via microRNA-20b-3p/DEP domain containing 1 (miR-20b-3p/DEPDC1) axis. CRC tissues that were resistant or sensitive to L-OHP were harvested, in which SIRT1, miR-20b-3p, and DEPDC1 levels were tested. L-OHP-resistant-resistant CRC cells were transfected, subsequently, cellular proliferation, invasion, migration, and apoptosis were tested, and tumor resistance to L-OHP was observed. The binding of SIRT1 to miR-20b-3p promoter and the targeting relationship between miR-20b-3p and DEPDC1 were verified. An aberrant elevation in SIRT1 expression was seen in L-OHP-resistant CRC tissues and cells. Knockdown of SIRT1 sensitized CRC cells and xenografted CRC tumors to L-OHP. SIRT1 bound with miR-20b-3p promoter to regulate DEPDC1. Reducing miR-20b-3p or raising DEPDC1 levels weakened the effect of SIRT1 knockdown on L-OHP-resistant-CRC cells. SIRT1 enhances L-OHP resistance in CRC by mediating miR-20b-3p/DEPDC1 axis.

DPP10-AS1-Mediated Downregulation of MicroRNA-324-3p Is Conducive to the Malignancy of Pancreatic Cancer by Enhancing CLDN3 Expression

OBJECTIVES

Network of long noncoding RNA-microRNA (miRNA)-mRNA is becoming increasingly pivotal roles in carcinogenesis mechanism. Herein, we aim to delineate the mechanistic understanding of dipeptidyl peptidase like 10-antisense RNA 1 (DPP10-AS1)/miRNA-324-3p/claudin 3 (CLDN3) axis in the malignancy of pancreatic cancer (PC).

METHODS

Microarray profiling and other bioinformatics methods were adopted to predict differentially expressed long noncoding RNA-miRNA-mRNA in PC, followed by verification of expression of DPP10-AS1, microRNA-324-3p (miR-324-3p), and CLDN3 in PC cells. The relationship among DPP10-AS1, miR-324-3p, and CLDN3 were further assessed. The PC cell invasion and migration were evaluated by scratch test and transwell assay. Tumor formation and lymph node metastasis were assessed in nude mice.

RESULTS

Highly expressed DPP10-AS1 and CLDN3 and poorly expressed miR-324-3p were identified in PC cells. The competitively binding between DPP10-AS1 and miR-324-3p was identified, and CLDN3 was targeted and downregulated by miR-324-3p. In addition, DPP10-AS1 was found to sequester miR-324-3p to release CLDN3 expression. DPP10-AS1 knockdown or miR-324-3p restoration diminished migration, invasion, tumor formation, microvessel density, and lymph node metastasis of PC cells, which was associated with CLDN3 downregulation.

CONCLUSIONS

Taken together, the study identified the regulatory role of DPP10-AS1/miR-324-3p/CLDN3 axis in PC, offering a mechanistic basis suggesting DPP10-AS1 ablation as a therapeutic target against PC.

A review on the role of miRNA-324 in various diseases

Recent studies have revealed important functions of several microRNAs (miRNAs) in the pathogenesis of human diseases. miR-324 is an example of miRNAs with crucial impacts on the pathogenesis of a wide range of disorders. Gene ontology studies have indicated possible role of miR-324 in responses of cells to the leukemia inhibitory factor, long-term synaptic potentiation, positive regulation of cytokines production and sensory perception of sound. In human, miR-324 is encoded by MIR324 gene which resides on chromosome 17p13.1. In the current manuscript, we provide a concise review of the role of miR-324 in the pathogenesis of cancers as well as non-cancerous conditions such as aneurysmal subarachnoid hemorrhage, diabetic nephropathy, epilepsy, pulmonary/renal fibrosis, ischemic stroke and ischemia reperfusion injuries. Moreover, we summarize the role of this miRNA as a prognostic marker for malignant disorders.

MALAT1 in colorectal cancer: Its implication as a diagnostic, prognostic, and predictive biomarker

Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), originally described as a prognostic biomarker remarkably linked with metastasis potential in lung cancer, has been identified as contributing to many diseases, including colorectal cancer (CRC). This long non-coding RNA (lncRNA) has come to the forefront of lncRNA research for its implications in cancer-related processes, such as cell proliferation and migration. In general, lncRNAs are recognized as enhancers, scaffolds, or decoys for a variety of oncogenes and tumor suppressors, although our understanding of lncRNA functions and mechanisms of action is still limited. Nowadays, cancer research is attracted to lncRNAs' ability to improve the early diagnosis of cancer, determine patients' prognosis, or predict therapy outcomes. In this review, we aimed to evaluate recent publications trying to uncover the cellular mechanisms of MALAT1-mediated regulation, and its potential exploitation in the management of CRC. The conclusions of this review provide robust support for the essential role of MALAT1 in CRC development and future personalized therapy.

Long non-coding RNAs (lncRNAs); roles in tumorigenesis and potentials as biomarkers in cancer diagnosis

New research has indicated that long non-coding RNAs (lncRNAs) play critical roles in a broad range of biological processes, including the pathogenesis of many complex human diseases, including cancer. The detailed regulation mechanisms of many lncRNAs in cancer initiation and progression have yet to be discovered, even though a few of lncRNAs' functions in cancer have been characterized. In the present study, we summarize recent advances in the mechanisms and functions of lncRNAs in cancer. We focused on the roles of newly-identified lncRNAs as oncogenes and tumor suppressors, as well as the potential pathways these molecules could play. The paper also discusses their potential uses as biomarkers for the diagnosis and prognosis of cancer.

Early-stage colon cancer with high MALAT1 expression is associated with the 5-Fluorouracil resistance and future metastasis

BACKGROUND

This study aimed to investigate the role of long noncoding RNA (LncRNA) expression profiles to predict relapse and 5-FU response in patients with stage I/II colon cancer (CC).

METHODS AND RESULTS

The expression level of 15 LncRNA was analyzed in stage I/II colon tumors of 126 CC patients. To confirm the findings in-vitro, 5FU-resistant HT29 cells were generated by subjecting HT-29 cells to the increasing concentrations of 5FU for 6 months. The 5FU resistance was observed in WST-1 and Annexin V analyses. The colony formation and wound healing assays were assessed to determine the metastatic properties of the cells. Expression levels of LncRNAs and mRNA of EMT-related genes were determined by RT-PCR. The role of LncRNA on metastasis and 5FU sensitivity were confirmed in pcDNA3.0-PTENP1 and si-MALAT1 expressed 5FU-resistant HT29 cell lineages.

RESULTS

High MALAT1 (p = 0.0002) and low PTENP1 (p = 0.0044) expressions were significantly associated with 5-FU resistance and tumor relapse in stage I/II CC. The invasiveness and colony-forming characteristics of 5-FU-resistant cell lineages were higher as compared to the parent HT-29. Moreover, the expression of MALAT1 (p = 0.0009) was increased while the expression of PTENP1 (p = 0.0158) decreased in 5FU-resistant-HT-29 cells. Si-MALAT1 treatment increased cell sensitivity to 5FU, whereas it decreased invasive behaviors of 5 FU-resistant-HT-29 cells.

CONCLUSION

MALAT1 may be a biomarker in predicting recurrence in early-stage CC. Our findings suggest that a cell-based therapy to target MALAT1 could be established for these patients to prevent metastasis and 5-FU resistance.

Allicin Inhibits Osteosarcoma Growth by Promoting Oxidative Stress and Autophagy via the Inactivation of the lncRNA MALAT1-miR-376a-Wnt/β-Catenin Signaling Pathway

Allicin, an organic sulfur compound extracted from the bulb of Allium sativum, can potentially prevent various tumors. Our previous study found that allicin can effectively suppress the proliferation of osteosarcoma cells. However, the molecular mechanisms have not been illustrated. In this study, Saos-2 and U2OS osteosarcoma cells were used to investigate the underlying mechanisms. A series of experiments were carried out to authenticate the anticancer property of allicin. Knockdown of lncRNA MALAT1 inhibited the proliferation, invasion and migration and promoted apoptosis of osteosarcoma cells. Knockdown of miR-376a increased the proliferation, invasion, and migration and dropped apoptosis of osteosarcoma cells. Furthermore, knockdown of miR-376a reversed the influences of MALAT1 silencing in osteosarcoma cells. Based on our data, MALAT1 could downregulate the expression of miR-376a, subsequently accelerating osteosarcoma. Moreover, oxidative stress and autophagy were identified as the potential key pathway of allicin. Allicin inhibited osteosarcoma growth and promoted oxidative stress and autophagy via MALATI-miR-376a. We also found that allicin promotes oxidative stress and autophagy to inhibit osteosarcoma growth by inhibiting the Wnt/β-catenin pathway in vivo and in vitro. All data showed that allicin promotes oxidative stress and autophagy of osteosarcoma via the MALATI-miR-376a-Wnt/β-catenin pathway.

Asiatic acid re-sensitizes multidrug-resistant A549/DDP cells to cisplatin by down regulating long non-coding RNA metastasis associated lung adenocarcinoma transcript 1/β-catenin signaling

Drug resistance becomes a challenge in the therapeutic management of non-small cell lung cancer (NSCLC). According to our former research, asiatic acid (AA) re-sensitized A549/DDP cells to cisplatin (DDP) through decreasing multidrug resistance protein 1 (MDR1) expression level. However, the relevant underlying mechanisms are still unclear. Long non-coding RNA (lncRNA) MALAT1 shows close association with chemo-resistance. As reported in this research, AA increased apoptosis rate, down regulated the expression of MALAT1, p300, β-catenin, and MDR1, up regulated the expression of miR-1297, and decreased β-catenin nuclear translocation in A549/DDP cells. MALAT1 knockdown expression abolished the drug resistance of A549/DDP cells and increased cell apoptosis. MALAT1 could potentially produce interactions with miR-1297, which targeted to degradation of p300. In addition, p300 overexpression effectively rescued the effects of MALAT1 knockdown expression on A549/DDP cells and activate the expression of β-catenin/MDR1 signaling, and these could be effectively blocked by AA treatment. Conclusively, AA could re-sensitize A549/DDP cells to DDP through down-regulating MALAT1/miR-1297/p300/β-catenin signaling.

Comprehensive analysis of ceRNA network of ERCC4 in colorectal cancer

Objective

ERCC4 is one of the most significant molecules of Nucleotide Excision Repair (NER), which has been researched due to its high expression in colorectal cancer (CRC). This study aimed to find out the ceRNA (competitive endogenous RNA) network of ERCC4 in CRC.

Methods and Materials

Pan cancer mRNA expression of ERCC4 was evaluated using TCGA database. The protein expression of ERCC4 was evaluated based on the Human Protein Atlas (HPA). We screened DElncRNAs and DEmiRNAs in two groups of ERCC4^high and ERCC4^low expression in CRC. Then a lncRNA-miRNA-ERCC4 regulatory network was constructed based on DElncRNAs and DEmiRNAs using Starbase database and visualized by Cytoscape software. Kaplan-Meier analysis was performed to evaluate the prognostic value of the ceRNA network. Further, RT-PCR was performed to validate the expression of the representative molecules in the ceRNA network in CRC and normal tissues. The relationship between drug sensitivity and these molecules were also evaluated using RNAactDrug database.

Results

ERCC4 was overexpressed in a variety of tumors at mRNA levels, including CRC. High expression of ERCC4 was also observed on protein level in CRC. A total of 1,885 DElncRNAs and 68 DEmiRNAs were identified from CRC samples in ERCC4^high and ERCC4^low expression groups. Predicted by the Starbase database, we got interacting miRNAs and lncRNAs of ERCC4 from the DEmiRNAs and DElncRNAs, and a lncRNA-miRNA-ERCC4 regulatory network was constructed. Kaplan-Meier survival curves results showed that miR-200c-3p (hazard ratio [HR] = 0.62, P = 0.032), MALAT1 (HR = 1.54, P = 0.016), and AC005520.2 (hazard ratio [HR] = 1.75, P = 0.002) were significantly associated with the prognosis of CRC. After validation by RT-PCR, we found that ERCC4 and MALAT1 were up-regulated in CRC compared with normal tissues, while miR-200c-3p was down-regulated. A strong negative correlation was observed between MALAT1 and miR-200c-3p. Drug sensitivity analysis showed that ERCC4, miR-200c and MALAT1 were all associated with Cisplatin.

Conclusion

We constructed a ceRNA network of ERCC4 in CRC, of which the MALAT1-miR-200c-3p-ERCC4 axis may be involved in the development, prognosis and chemotherapy sensitivity of CRC. These findings might provide novel clues and insights on the molecular mechanisms of ERCC4 and NER pathway in CRC.

Down-regulation of ZNF252P-AS1 alleviates ovarian cancer progression by binding miR-324-3p to downregulate LY6K

Background

Ovarian cancer is a common gynecological malignant disease in women. Our work aimed to study the specific functions of ZNF252P antisense RNA 1 (ZNF252P-AS1) in ovarian cancer.

Methods

ZNF252P-AS1, miR-324-3p, and lymphocyte antigen 6 family member K (LY6K) expression were analyzed by bioinformatics tools in ovarian cancer tissues and was quantified by qRT-PCR in ovarian cancer cells. The effect of ZNF252P-AS1 knockdown, miR-324-3p suppression, and LY6K over-expression on apoptosis, cell viability, invasion, migration, and epithelial to mesenchymal transition (EMT) was determined in vitro by using colony formation and EdU assays, flow cytometry, transwell assay, and Western blot. The interactions between ZNF252P-AS1 and miR-324-3p and between miR-324-3p and LY6K were validated by luciferase assays. The effects of restraining ZNF252P-AS1 in vivo were studied using BALB/c male nude mice.

Results

ZNF252P-AS1 and LY6K levels were up-regulated, while miR-324-3p was declined in ovarian cancer tissues and cells. ZNF252P-AS1 knockdown reduced ovarian cancer cell proliferation, invasion, migration, and EMT, whereas promoted its apoptosis. Besides, ZNF252P-AS1 interacted with miR-324-3p and reversely regulated its level, and miR-324-3p was directly bound to LY6K and negatively regulated its expression. Moreover, ZNF252P-AS1 knockdown reversed the effect of miR-324-3p on cancer cell apoptosis, growth, migration, invasion, and EMT. Similar results were discovered in the rescue experiments between miR-324-3p and LY6K. Additionally, mouse models in vivo experiments further validated that ZNF252P-AS1 knockdown distinctly inhibited tumor growth.

Conclusion

ZNF252P-AS1 mediated miR-324-3p/LY6K signaling to facilitate progression of ovarian cancer.

Long Non-Coding RNAs as Potential Diagnostic and Prognostic Biomarkers in Breast Cancer: Progress and Prospects

Breast cancer is the most common malignancy among women worldwide, excluding non-melanoma skin cancer. It is now well understood that breast cancer is a heterogeneous entity that exhibits distinctive histological and biological features, treatment responses and prognostic patterns. Therefore, the identification of novel ideal diagnostic and prognostic biomarkers is of utmost importance. Long non-coding RNAs (lncRNAs) are commonly defined as transcripts longer than 200 nucleotides that lack coding potential. Extensive research has shown that lncRNAs are involved in multiple human cancers, including breast cancer. LncRNAs with dysregulated expression can act as oncogenes or tumor-suppressor genes to regulate malignant transformation processes, such as proliferation, invasion, migration and drug resistance. Intriguingly, the expression profiles of lncRNAs tend to be highly cell-type-specific, tissue-specific, disease-specific or developmental stage-specific, which makes them suitable biomarkers for breast cancer diagnosis and prognosis.

Mutant p53 Mediates Sensitivity to Cancer Treatment Agents in Oesophageal Adenocarcinoma Associated with MicroRNA and SLC7A11 Expression

TP53 gene mutations occur in 70% of oesophageal adenocarcinomas (OACs). Given the central role of p53 in controlling cellular response to therapy we investigated the role of mutant (mut-) p53 and SLC7A11 in a CRISPR-mediated JH-EsoAd1 TP53 knockout model. Response to 2 Gy irradiation, cisplatin, 5-FU, 4-hydroxytamoxifen, and endoxifen was assessed, followed by a TaqMan OpenArray qPCR screening for differences in miRNA expression. Knockout of mut-p53 resulted in increased chemo- and radioresistance (2 Gy survival fraction: 38% vs. 56%, p < 0.0001) and in altered miRNA expression levels. Target mRNA pathways analyses indicated several potential mechanisms of treatment resistance. SLC7A11 knockdown restored radiosensitivity (2 Gy SF: 46% vs. 73%; p = 0.0239), possibly via enhanced sensitivity to oxidative stress. Pathway analysis of the mRNA targets of differentially expressed miRNAs indicated potential involvement in several pathways associated with apoptosis, ribosomes, and p53 signaling pathways. The data suggest that mut-p53 in JH-EsoAd1, despite being classified as non-functional, has some function related to radio- and chemoresistance. The results also highlight the important role of SLC7A11 in cancer metabolism and redox balance and the influence of p53 on these processes. Inhibition of the SLC7A11-glutathione axis may represent a promising approach to overcome resistance associated with mut-p53.

The Mechanistic Roles of ncRNAs in Promoting and Supporting Chemoresistance of Colorectal Cancer

Colorectal Cancer (CRC) is one of the most common gastrointestinal malignancies which has quite a high mortality rate. Despite the advances made in CRC treatment, effective therapy is still quite challenging, particularly due to resistance arising throughout the treatment regimen. Several studies have been carried out to identify CRC chemoresistance mechanisms, with research showing different signalling pathways, certain ATP binding cassette (ABC) transporters and epithelial mesenchymal transition (EMT), among others to be responsible for the failure of CRC chemotherapies. In the last decade, it has become increasingly evident that certain non-coding RNA (ncRNA) families are involved in chemoresistance. Research investigations have demonstrated that dysregulation of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) contribute towards promoting resistance in CRC via different mechanisms. Considering the currently available data on this phenomenon, a better understanding of how these ncRNAs participate in chemoresistance can lead to suitable solutions to overcome this problem in CRC. This review will first focus on discussing the different mechanisms of CRC resistance identified so far. The focus will then shift onto the roles of miRNAs, lncRNAs and circRNAs in promoting 5-fluorouracil (5-FU), oxaliplatin (OXA), cisplatin and doxorubicin (DOX) resistance in CRC, specifically using ncRNAs which have been recently identified and validated under in vivo or in vitro conditions.

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.

The role of a ceRNA regulatory network based on lncRNA MALAT1 site in cancer progression

As a type of non-coding RNA of more than 200 nucleotides, long non-coding RNAs(lncRNAs) lack protein coding ability and can regulate gene expression. MicroRNAs(miRNAs), which are also non-coding RNAs, are short single-stranded RNAs, usually composed of 18-23 nucleotides. MiRNAs inhibits gene expression by specifically binding to the 3'-UTR of downstream target mRNAs and can function as oncogenes or suppressor oncogenes to regulate the occurrence and development of cancer. LncRNAs can function as competitive endogenous RNAs that bind to miRNAs, resulting in the recovery of downstream mRNA expression and activity. The regulatory network existing between lncRNAs, miRNAs and mRNAs regulates a variety of biological processes, including cell proliferation, apoptosis, migration and invasion as well as cell-cycle arrest. Disruption of the ceRNA network affects cell growth and development and often leads to various diseases, especially cancer. The lncRNA MALAT1, which is located on chromosome 11q13, contains more than 8000 nucleotides and is implicated in the occurrence and development of many cancers. Here, we review the impact of the ceRNA network and the lncRNA MALAT1 in cancer.