lncRNA UCA1 Mediates Resistance to Cisplatin by Regulating the miR-143/FOSL2-Signaling Pathway in Ovarian Cancer

Back to the Future: Rethinking the Great Potential of lncRNAS for Optimizing Chemotherapeutic Response in Ovarian Cancer

Ovarian cancer (OC) is one of the most fatal cancers in women worldwide. Currently, platinum- and taxane-based chemotherapy is the mainstay for the treatment of OC. Yet, the emergence of chemoresistance results in therapeutic failure and significant relapse despite a consistent rate of primary response. Emerging evidence substantiates the potential role of lncRNAs in determining the response to standard chemotherapy in OC. The objective of this narrative review is to provide an integrated, synthesized overview of the current state of knowledge regarding the role of lncRNAs in the emergence of resistance to platinum- and taxane-based chemotherapy in OC. In addition, we sought to develop conceptual frameworks for harnessing the therapeutic potential of lncRNAs in strategies aimed at enhancing the chemotherapy response of OC. Furthermore, we offered significant new perspectives and insights on the interplay between lncRNAs and the molecular circuitries implicated in chemoresistance to determine their impacts on therapeutic response. Although this review summarizes robust data concerning the involvement of lncRNAs in the emergence of acquired resistance to platinum- and taxane-based chemotherapy in OC, effective approaches for translating these lncRNAs into clinical practice warrant further investigation.

Hsa_circ_0003998 promotes epithelial to mesenchymal transition of hepatocellular carcinoma by sponging miR-143-3p and PCBP1

BACKGROUND

Circular RNAs (circRNAs) play a critical regulatory role in cancer progression. However, the underlying mechanisms of circRNAs in hepatocellular carcinoma (HCC) metastasis remain mostly unknown.

METHODS

Has_circ_0003998 (circ0003998) was identified by RNAs sequencing in HCC patients with /without portal vein tumor thrombus (PVTT) metastasis. The expression level of circ0003998 was further detected by in situ hybridization on tissues microarray (ISH-TMA) and qRT-PCR in 25 HCC patients with PVTT metastasis. Moreover, the 25 HCC patients with PVTT metastasis and 50 HCC patients without PVTT metastasis were recruited together to analyze the correlation between circ0003998 expression and HCC clinical characteristics. Transwell, migration and CCK8 assays, as well as nude mice model of lung or liver metastasis were used to evaluate the role of circ0003998 in epithelial to mesenchymal transition (EMT) in HCC. The regulatory mechanisms of circ0003998 in miR-143-3p and PCBP1 were determined by dual-luciferase reporter assay, nuclear-cytoplasmic fractionation, fluorescent in situ hybridization, RNA pull- down, microRNA sequence, western blot and RNA immunoprecipitation.

RESULTS

Compared with adjacent normal liver tissues (ANL), circ0003998 expression was significantly upregulated in PVTT tissues and HCC tissues, and its expression correlates with the aggressive characteristics of HCC patients. Further assays suggested that circ0003998 promoted EMT of HCC both in vitro and in vivo. Mechanistically, our data indicated that circ0003998 may act as a ceRNA (competing endogenous RNA) of microRNA-143-3p to relieve the repressive effect on EMT-related stimulator, FOSL2; meanwhile, circ0003998 could bind with PCBP1-poly(rC) binding protein 1 (PCBP1) to increase the expression level of EMT-related genes, CD44v6.

CONCLUSION

Circ0003998 promotes EMT of HCC by circ0003998/miR-143-3p/FOSL2 axis and circ0003998 /PCBP1/CD44v6 axis.

LncRNA HOTAIR Contributes to Sorafenib Resistance through Suppressing miR-217 in Hepatic Carcinoma

Background

Sorafenib is a multi-target kinase inhibitor that has been approved as a unique target drug for the treatment of advanced hepatocellular carcinoma (HCC). However, due to the frequent occurrence of drug resistance, its treatment efficacy is often limited. The aim of this study was to explore the function of HOX transcript antisense intergenic RNA (HOTAIR) for the treatment of HCC with sorafenib, and its underlying mechanism.

Methods

A cell counting kit-8 (CCK-8) assay and Edu assay were used to examine the viability and proliferation of HCC cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of HOTAIR and miR-217 in HCC cells. Small interfering (si) RNA was transfected to knockdown HOTAIR to explore its biological function. A Western blot and immunofluorescence were performed to detect the level of E-cadherin and Vimentin expression.

Results

Sorafenib resistance was increased in HCC cells with high HOTAIR expression. Moreover, a knockdown of HOTAIR could improve the therapeutic effect of sorafenib on HCC via increasing E-cadherin and decreasing Vimentin expression. Additionally, a HOTAIR knockdown could increase the sensitivity of sorafenib for HCC treatment by up-regulating miR-217.

Conclusions

Lnc HOTAIR could increase sorafenib resistance in HCC by inhibiting miR-217. Our research attempts to elucidate a more effective treatment and provides novel insight into potential clinical treatment for HCC.

Long Non-Coding RNA OIP5-AS1 Knockdown Enhances CDDP Sensitivity in Osteosarcoma via miR-377-3p/FOSL2 Axis

Background

Drug resistance is one of big obstacles for the treatment of tumor. Long non-coding RNA Opa-interacting protein 5-antisense RNA 1 (OIP5-AS1) was identified to involve in drug resistance. In this research, the effects of OIP5-AS1 on cisplatin (CDDP) resistance in osteosarcoma (OS) were mainly investigated.

Methods

The levels of OIP5-AS1, microRNA-377-3p (miR-377-3p), and FOS like 2 (FOSL2) were measured by quantitative real-time polymerase chain reaction. The inhibitory concentration 50 (IC₅₀) value of CDDP, cell viability and apoptotic rate was evaluated through Cell Counting Kit-8 and flow cytometry assays, respectively. The levels of multidrug resistance-associated protein 1 (MRP1), P-glycoprotein, B-cell lymphoma 2, Bcl2-associated X, cleaved-caspase-3, and FOSL2 were detected by Western blot assay. The interaction between miR-377-3p and OIP5-AS1 or FOSL2 was verified by Dual-Luciferase Reporter and RNA Immunoprecipitation assays. The function of OIP5-AS1 was detected by a xenograft tumor model in vivo.

Results

OIP5-AS1 and FOSL2 were up-regulated, while miR-377-3p was down-regulated in CDDP-resistant OS tissues and cells. OIP5-AS1 silencing inhibited cell viability and the IC₅₀ value of CDDP, and promoted apoptotic rate in CDDP-resistant OS cells. Mechanically, OIP5-AS1 was verified as a sponge to miR-377-3p and FOSL2 was a target of miR-377-3p. Moreover, OIP5-AS1 knockdown repressed OS tumor growth and enhanced CDDP sensitivity of OS in vivo.

Conclusion

OIP5-AS1 positively modulated FOSL2 expression to decrease CDDP sensitivity in OS by sponging miR-377-3p.

microRNAs as biomarkers of ovarian cancer

Introduction: Ovarian carcinoma (OC) is the leading cause of death in women with gynecologic cancers. Most patients are diagnosed at an advanced stage with a low five-year survival rate of 20-30%. Discovering novel biomarkers for early detection and outcome prediction of OC is an urgent medical need. miRNAs, a group of small non-coding RNAs, play critical roles in multiple biologic processes and cancer pathogenesis.Areas covered: We provide an in-depth look at the functions of miRNAs in OC, particularly focusing on their roles in chemoresistance and metastasis in OC. We also discuss the biological and clinical significance of miRNAs in exosomes and expand on long non-coding RNA which acts as ceRNA of miRNAs.Expert opinion: miRNAs participate in many biological processes including proliferation, apoptosis, chemoresistance, metastasis, epithelial-mesenchymal transition, and cancer stem cell. They will substantially contribute to our understanding of OC pathogenesis. Given their resistance to the degradation of ribonucleases and availability in plasma exosomes, miRNAs may serve as emerging biomarkers for cancer detection, therapeutic assessment, and prognostic prediction. Being a messenger, exosomal miRNAs are crucial for the crosstalk between cancer cells and stromal cells in tumor microenvironment.

Long Non-Coding RNA UCA1 Modulates Paclitaxel Resistance in Breast Cancer via miR-613/CDK12 Axis

Background

Paclitaxel (PTX) occupies a considerable status in the chemotherapies of breast cancer (BC), but the drug resistance keeps an obstructive factor of PTX treatment. This study was designed to explore the molecular mechanism of long non-coding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) in PTX resistance of BC.

Methods

UCA1, microRNA-613 (miR-613) and cyclin-dependent kinase 12 (CDK12) expression was assayed through quantitative real-time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8 (CCK-8) assay was implemented for evaluating the half inhibitory concentrations (IC₅₀) of PTX and cell viability. Cell apoptosis was examined by flow cytometry. The target relationship was explored using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. CDK12 protein level was detected through Western blot. Xenograft tumor assay was applied for assessing the influence of UCA1 on PTX resistance of BC in vivo.

Results

UCA1 expressed highly in PTX-resistant BC tissues and cells and regulated PTX resistance in BC cells by affecting cell viability and apoptosis in part. UCA1 negatively interacted with miR-613 and modulated PTX resistance via sponging miR-613. CDK12 was a downstream gene of miR-613 and miR-613 exerted the modulation of PTX resistance via targeting CDK12. Furthermore, UCA1 regulated CDK12 level through interacting with miR-613. The regulatory role of UCA1 in PTX resistance of BC was achieved by miR-613/CDK12 axis in vivo.

Conclusion

UCA1 mediated PTX resistance in BC through the miR-613/CDK12 axis, manifesting that UCA1 might improve the PTX treatment of BC as a significant therapeutic biomarker.

LncRNA UCA1 promotes cisplatin resistance in gastric cancer via recruiting EZH2 and activating PI3K/AKT pathway

Background: Drug resistance of cancer cells is one of the major causes of chemotherapy failure. Recently research demonstrated that long non-coding RNA Urothelial cancer associated 1 (UCA1) could promote tumor cisplatin resistance. In this study, we aim to investigate the role of UCA1 in the cisplatin treatment of gastric cancer and its underlying mechanism. Methods: Cell counting kit-8 (CCK-8) assay and apoptosis assay were used to detect the effects of different doses of cisplatin on the proliferation and apoptosis of gastric cancer. We examined the expression relationship between the Enhancer of Zeste Homologue 2 (EZH2) and UCA1 by quantitative Real-time polymerase chain reaction (qRT-PCR) and western blot analysis. Western blot analysis was also performed to detect the expression levels of apoptosis-related proteins, EZH2 and key genes in PI3K/AKT signaling pathway, RIP and RNA pull down assays were performed to explore the interaction between UCA1 and EZH2. Results: We demonstrated that higher the UCA1 expression levels in GC tissues correlated with the poorer the prognosis of patients according to the TCGA database, the GEO database. Moreover, overexpression of UCA1 promotes GC cell proliferation and inhibits cisplatin-induced apoptosis. Knockdown of UCA1 showed the opposite results. Besides, UCA1 exerted its function through interacting with EZH2 and regulates EZH2 expression, knockdown of EZH2 decreased cisplatin resistance of GC cells. Hence, UCA1 promotes cisplatin resistance of GC via recruiting EZH2 and activating PI3K/AKT pathway. Conclusion: Our research revealed the lncRNA UCA1 promoted the cisplatin resistance of GC by recruiting EZH2 and activating PI3K/AKT pathway to modulate cell apoptosis, indicating treatments targeting UCA1 or EZH2 might provide meaningful therapeutic strategies for cisplatin-resistance GC patients.

LncRNA MALAT1 Regulates the Cell Proliferation and Cisplatin Resistance in Gastric Cancer via PI3K/AKT Pathway

Background

Many studies showed that long non-coding RNA MALAT1 is served as an oncogene. However, the specific role of MALAT1 in gastric cancer is not fully elucidated. The aim of this study is to elucidate the regulatory effects of MALAT1 on tumor development and cisplatin resistance in gastric cancer.

Methods

TCGA database was applied to investigate the expression levels of MALAT1 in GC tissues and normal gastric tissues and its correlation with GC patients’ survival. Univariate and multivariate analysis were performed to investigate whether MALAT1 expression is an independent risk for overall survival of gastric cancer patients. The expression of MALAT1 was detected by Quantitative real-time PCR. After knockdown or overexpression of MALAT1, the cellular functions of GC cells were detected by cell-proliferation, flow cytometry, transwell assay and colony formation assays, respectively. Western blot analysis was performed to detect the protein levels of Bcl-2 and key genes in the PI3K/AKT pathway in GC cells. Finally, CCK-8 assay was performed to explore the effect of MALAT1 on cisplatin resistance of GC cells.

Results

Higher expression of MALAT1 was detected in GC tissues than that of adjacent normal tissues, high MALAT1 expression is an independent risk for overall survival of gastric cancer patients. Knockdown of MALAT1 inhibited proliferation, migration and invasion of GC cells, while overexpression of MALAT1 Overexpression of MALAT1 yielded opposite results. Western blot results showed that protein expressions of p-PI3K, p-AKT and p-STAT3 were downregulated after MALAT1 knockdown in GC cells, while these proteins were upregulated after MALAT1 overexpression. Additionally, the IC₅₀ in MGC803/CDDP cells transfected with si-MALAT1 was lower than in those transfected with si-NC. The apoptotic rate in MGC803 cells transfected with pcDNA-MALAT1 was remarkably lower than those transfected with NC.

Conclusion

We demonstrated that MALAT1 is highly expressed in GC, high MALAT1 expression is an independent risk factor for OS among GC patients. Moreover, MALAT1 promotes malignant progression of GC and contributes to cisplatin resistance of GC cells, indicating MALAT1 may serve as a biological hallmark for predicting the prognosis of GC.

Insights into new mechanisms and models of cancer stem cell multidrug resistance

The acquisition of genetic alterations, clonal evolution, and the tumor microenvironment promote cancer progression, metastasis and therapy resistance. These events correspond to the establishment of the great phenotypic heterogeneity and plasticity of cancer cells that contribute to tumor progression and resistant disease. Targeting resistant cancers is a major challenge in oncology; however, the underlying processes are not yet fully understood. Even though current treatments can reduce tumor size and increase life expectancy, relapse and multidrug resistance (MDR) ultimately remain the second cause of death in developed countries. Recent evidence points toward stem-like phenotypes in cancer cells, promoted by cancer stem cells (CSCs), as the main culprit of cancer relapse, resistance (radiotherapy, hormone therapy, and/or chemotherapy) and metastasis. Many mechanisms have been proposed for CSC resistance, such as drug efflux through ABC transporters, overactivation of the DNA damage response (DDR), apoptosis evasion, prosurvival pathways activation, cell cycle promotion and/or cell metabolic alterations. Nonetheless, targeted therapy toward these specific CSC mechanisms is only partially effective to prevent or abolish resistance, suggesting underlying additional causes for CSC resilience. This article aims to provide an integrated picture of the MDR mechanisms that operate in CSCs' behavior and to propose a novel model of tumor evolution during chemotherapy. Targeting the pathways mentioned here might hold promise and reveal new strategies for future clinical therapeutic approaches.

Long non-coding RNA UCA1 promotes malignant phenotypes of renal cancer cells by modulating the miR-182-5p/DLL4 axis as a ceRNA

Background

Accumulating literatures have indicated that long non-coding RNAs (lncRNAs) are potential biomarkers that play key roles in tumor development and progression. Urothelial cancer associated 1 (UCA1) is a novel lncRNA that acts as a potential biomarker and is involved in the development of cancers. However, the molecular mechanism of UCA1 in renal cancer is still needed to further explore.

Methods

The relative expression level of UCA1 was determined by Real-Time qPCR in a total of 88 patients with urothelial renal cancer and in different renal cancer cell lines. Loss-of-function experiments were performed to investigate the biological roles of UCA1 and miR-182-5p on renal cancer cell proliferation, migration, apoptosis and tumorigenicity. Comprehensive transcriptional analysis, dual-luciferase reporter assay and western blot etc. were performed to explore the molecular mechanisms underlying the functions of UCA1.

Results

In this study, we found that UCA1 was significantly up-regulated in renal cancer. Moreover, increased UCA1 expression was positively correlated with differentiation and advanced TNM stage. Further experiments demonstrated that knockdown of UCA1 inhibited malignant phenotypes and Notch signal path of renal cancer cells, and miR-182-5p was reverse function as UCA1. UCA1 functioned as a miRNA sponge to positively regulate the expression of Delta-like ligand 4(DLL4) through sponging miR-182-5p and subsequently promoted malignant phenotypes of renal cancer cells, thus UCA1 playing an oncogenic role and miR-182-5p as an antioncogenic one in renal cancer pathogenesis.

Conclusion

UCA1-miR-182-5p-DLL4 axis is involved in proliferation and progression of renal cancer. Thus, this study demonstrated that UCA1 plays a critical regulatory role in renal cancer cell and UCA1 may serve as a potential diagnostic biomarker and therapeutic target of renal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-020-1132-x.

Long Non-coding RNAs Involved in Resistance to Chemotherapy in Ovarian Cancer

Ovarian cancer (OC) accounts for more than 150,000 deaths worldwide every year. Patients are often diagnosed at an advanced stage with metastatic dissemination. Although platinum- and taxane-based chemotherapies are effective treatment options, they are rarely curative and eventually, the disease will progress due to acquired resistance. Emerging evidence suggests a crucial role of long non-coding RNAs (lncRNAs) in the response to therapy in OC. Transcriptome profiling studies using high throughput approaches have identified differential expression patterns of lncRNAs associated with disease recurrence. Furthermore, several aberrantly expressed lncRNAs in resistant OC cells have been related to increased cell division, improved DNA repair, up-regulation of drug transporters or reduced susceptibility to apoptotic stimuli, supporting their involvement in acquired resistance. In this review, we will discuss the key aspects of lncRNAs associated with the development of resistance to platinum- and taxane-based chemotherapy in OC. The molecular landscape of OC will be introduced, to provide a background for understanding the role of lncRNAs in the acquisition of malignant properties. We will focus on the interplay between lncRNAs and molecular pathways affecting drug response to evaluate their impact on treatment resistance. Additionally, we will discuss the prospects of using lncRNAs as biomarkers or targets for precision medicine in OC. Although there is still plenty to learn about lncRNAs and technical challenges to be solved, the evidence of their involvement in OC and the development of acquired resistance are compelling and warrant further investigation for clinical applications.

Construction and Investigation of an LINC00284-Associated Regulatory Network in Serous Ovarian Carcinoma

The low survival rate associated with serous ovarian carcinoma (SOC) is largely due to the lack of relevant molecular markers for early detection and therapy. Increasing experimental evidence has demonstrated that long noncoding RNAs (lncRNAs) are involved in cancer initiation and development, and a competitive endogenous RNA (ceRNA) hypothesis has been formulated. Therefore, the characterization of new lncRNA and lncRNA-related networks is crucial for early diagnosis and targeted therapy of SOC. Data on lncRNAs, mRNAs, and miRNAs with differential expression in SOC, compared to normal ovarian tissue, were obtained from the Gene Expression Omnibus (GEO) database. Data on lncRNA expression and clinical data in SOC were obtained from The Cancer Genome Atlas (TCGA). lncRNA-miRNA interactions were predicted by the miRBase database. Different online tools, i.e., TargetScan, RNA22, miRmap, microT, miRanda, StarBase, and PicTar, were cooperatively utilized to predict the mRNAs targeted by miRNAs. The plugin of BiNGO in Cytoscape and KOBAS 3.0 were used to conduct the functional and pathway enrichment analyses. The lncRNA, miRNAs, and mRNAs identified to be expressed at statistically significant and different levels between SOC and healthy fallopian tube tissues were further validated using qRT-PCR. A total of 4 lncRNAs (LINC00284, HAGLR, HCAT158, and BLACAT1) and 111 mRNAs were found to be upregulated in SOC tissues compared to normal tissues, based on the GEO database. LINC00284 was found to be highly expressed in SOC, in association with the upregulation of the transcription factor SOX9. The high LINC00284 expression was associated with poor prognosis and proved to be an independent risk factor in patients with SOC, based on TCGA database. The qRT-PCR validation results closely recapitulated the expression profiles and prognostic scores of the aforementioned bioinformatic analyses. The LINC00284-related ceRNA network was found to be associated with SOC carcinogenesis by biofunctional analysis. In conclusion, the LINC00284-related ceRNA network may provide valuable information on the mechanisms of SOC initiation and progression. Importantly, LINC00284 proved to be a new potential prognostic biomarker for SOC.

HOTAIRM1 suppresses cell proliferation and invasion in ovarian cancer through facilitating ARHGAP24 expression by sponging miR-106a-5p

AIMS

Ovarian cancer (OC) is the most lethal gynecologic malignant tumors all over the world. HOX antisense intergenic RNA myeloid 1 (HOTAIRM1) has been reported as an important regulator in multiple tumors. However, the functions of HOTAIRM1 in OC and its possible molecular mechanisms remain unclear.

MAIN METHODS

qRT-PCR analysis was performed to detect the expression levels of HOTAIRM1, miR-106a-5p and ARHGAP24 mRNA in OC tissues and cells. The functional effects of HOTAIRM1, miR-106a-5p and ARHGAP24 on OC cells were determined by MTT, colony formation, flow cytometry and Transwell assays. Luciferase reporter, RIP and RNA pull-down assays were used to examine the interaction between miR-106a-5p and HOTAIRM1 or ARHGAP24. Tumor xenografts were constructed in nude mice to confirm the roles of HOTAIRM1 in OC in vivo.

KEY FINDINGS

HOTAIRM1 expression was lowered in OC tumor tissues and cells. Decreased HOTAIRM1 expression was associated with advanced FIGO stages and lymphatic metastasis. Up-regulation of HOTAIRM1 suppressed OC cell proliferation and invasion, and promoted apoptosis. Also, HOTAIRM1 slowed OC tumor growth in vivo. Moreover, HOTAIRM1 could serve as a competing endogenous RNA (ceRNA) of miR-106a-5p to derepress ARHGAP24 expression. HOTAIRM1-mediated inhibitory effect on OC progression was partly reversed following the restoration of miR-106a-5p expression. Furthermore, ARHGAP24 overexpression repressed OC progression in vitro.

SIGNIFICANCE

In conclusion, our study showed that HOTAIRM1 suppressed OC progression through derepression of ARHGAP24 by sponging miR-106a-5p. This finding provides novel insights into the mechanisms of HOTAIRM1 in OC and highlights a potential therapeutic strategy for the treatment of OC.

Advances in the study of exosomal lncRNAs in tumors and the selection of research methods

Exosomes are endosome-derived extracellular vesicles that are released upon the fusion of multivesicular bodies with the plasma membrane. These vesicles contain proteins, lipids, and nucleic acids and are found in various human body fluids. Exosomes can transfer bioactive molecules to nearby or distant recipient cells, thereby affecting their function. Recently, exosomes have gained importance as a medium of communication between tumor cells. An increasing number of studies have found that non-coding RNAs in tumor cell-derived exosomes can regulate tumor microenvironments, inhibit immune cell function, promote the growth and invasion of tumor cells, and impart resistance to chemicals in tumor cells. In this review, we focus on the effects of exosomal long non-coding RNAs (lncRNAs) on tumors. As exosomes and their parent cells have similar biological characteristics and coated lncRNAs can exist stably in vivo without being degraded by RNases, exosomal lncRNAs have emerged as novel non-invasive tumor biomarkers for use in the early diagnosis and evaluation of prognosis of tumors. Advancements in the field have led to the development of a variety of techniques in exosomal non-coding RNA research. Currently, most methods include the separation and purification of exosomes, followed by RNA extraction, reverse transcription, and subsequent analyses; thus, these processes are very tedious and vulnerable to contamination and could lead to inaccurate and inconsistent results. Thus, there has been an increase in the development of detection methods for exosomal RNAs. Here, we discuss the existing research methods, their advantages and disadvantages, and a few new techniques.

Long noncoding RNA 00976 promotes pancreatic cancer progression through OTUD7B by sponging miR-137 involving EGFR/MAPK pathway

BACKGROUND

Accumulation evidence indicates the vital role of long non-coding RNAs (lncRNAs) in tumorigenesis and the progression of malignant tumors, including pancreatic cancer (PC). However, the role and the molecular mechanism of long non-coding RNA 00976 is unclear in pancreatic cancer.

METHODS

In situ hybridization (ISH) and qRT-PCR was performed to investigate the association between linc00976 expression and the clinicopathological characteristics and prognosis of patients with PC. Subsequently, linc00976 over-expression vector and shRNAs were transfected into PC cells to up-regulate or down-regulate linc00976 expression. Loss- and gain-of function assays were performed to investigate the role of linc00976 in proliferation and metastasis in vitro and vivo. ITRAQ, bioinformatic analysis and rescue assay were used to illustrate the ceRNA mechanism network of linc00976/miR-137/OTUD7B and its downstream EGFR/MAPK signaling pathway.

RESULTS

linc00976 expression was overexpressed in PC tissues and cell lines and was positively associated with poorer survival in patients with PC. Function studies revealed that linc00976 knockdown significantly suppressed cell proliferation, migration and invasion in vivo and in vitro, whereas its overexpression reversed these effects. Based on Itraq results and online database prediction, Ovarian tumor proteases OTUD7B was found as a downstream gene of linc00976, which deubiquitinated EGFR mediates MAPK signaling activation. Furthermore, Bioinformatics analysis and luciferase assays and rescue experiments revealed that linc00976/miR137/OTUD7B established the ceRNA network modulating PC cell proliferation and tumor growth.

CONCLUSION

The present study demonstrates that linc00976 enhances the proliferation and invasion ability of PC cells by upregulating OTUD7B expression, which was a target of miR-137. Ultimately, OTUD7B mediates EGFR and MAPK signaling pathway, suggesting that linc00976/miR-137/OTUD7B/EGFR axis may act as a potential biomarker and therapeutic target for PC.

UCA1 long non-coding RNA: An update on its roles in malignant behavior of cancers

The lncRNA urothelial carcinoma-associated 1 (UCA1) is a 1.4 kb long transcript which has been firstly recognized in human bladder cancer cell line. Subsequent studies revealed its over-expression in a wide array of human cancer cell lines and patients' samples. In addition to conferring malignant phenotype to cells, it enhances resistance to conventional anti-cancer drugs. Moreover, transcript levels of this lncRNA have been regarded as diagnostic markers in several cancer types including gastric, bladder and liver cancers. The underlying mechanism of its participation in carcinogenesis has been identified in some cancer types. Sponging tumor suppressor miRNAs, interacting with cancer-promoting signaling pathways and enhancing cell cycle progression are among these mechanisms. Although few studies have shown anti-carcinogenic properties for this lncRNA, the bulk of evidence supports its oncogenic roles. In the current study, we have reviewed the current literature on the role of UCA1 in the carcinogenic process based on the results of in vitro studies, investigations in animal models and assessment of UCA1 expression in clinical samples.