scholarly journals Research Progress on the Functions and Mechanism of circRNA in Cisplatin Resistance in Tumors

2021 ◽  
Vol 12 ◽  
Author(s):  
Qingchun Mu ◽  
Yue Lv ◽  
Chunmei Luo ◽  
Xiaojing Liu ◽  
Chunming Huang ◽  
...  

Cisplatin is a common chemotherapeutic drug that has been used to treat of numerous tumors, including testicular, lung, bladder, ovarian, liver and head and neck cancers. Although clinical chemotherapy based on cisplatin has shown a remarkable therapeutic effect, the resistance to cisplatin becomes increasingly obvious as a patient uses it for a prolonged period. It not only affects the prognosis of these tumors, but also causes the recurrence of cancer and decreases the overall survival rate. The development of cisplatin resistance involves several mechanisms, including DNA damage repair, ATP-binding cassette (ABC) transporter, autophagy, cancer stem cells (CSCs), epithelial–mesenchymal transition (EMT), and other related signaling pathways. Interestingly, these mechanisms have been found to be influenced by circular RNAs (circRNAs) to regulate tumor proliferation, invasion, chemosensitivity, and other biological behaviors in the tumor microenvironment (TME). In recent years, circRNAs in cisplatin resistance in tumors, especially lung cancer and gastric cancer, have gradually drawn peoples’ attention. This review summarizes recent studies on the functions and mechanisms of circRNAs in cisplatin resistance. We emphasize that circRNA can be used as a promising target gene to improve drug resistance and therapeutic efficacy.

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Peng Li Zhou ◽  
Zhengyang Wu ◽  
Wenguang Zhang ◽  
Miao Xu ◽  
Jianzhuang Ren ◽  
...  

AbstractGrowing evidence has indicated that circular RNAs (circRNAs) play a pivotal role as functional RNAs in diverse cancers. However, most circRNAs involved in esophageal squamous cell carcinoma (ESCC) remain undefined, and the underlying molecular mechanisms mediated by circRNAs are largely unclear. Here, we screened human circRNA expression profiles in ESCC tissues and found significantly increased expression of hsa_circ_0000277 (termed circPDE3B) in ESCC tissues and cell lines compared to the normal controls. Moreover, higher circPDE3B expression in patients with ESCC was correlated with advanced tumor-node-metastasis (TNM) stage and dismal prognosis. Functional experiments demonstrated that circPDE3B promoted the tumorigenesis and metastasis of ESCC cells in vitro and in vivo. Mechanistically, bioinformatics analysis, a dual-luciferase reporter assay, and anti-AGO2 RNA immunoprecipitation showed that circPDE3B could act as a competing endogenous RNA (ceRNA) by harboring miR-4766-5p to eliminate the inhibitory effect on the target gene laminin α1 (LAMA1). In addition, LAMA1 was significantly upregulated in ESCC tissues and was positively associated with the aggressive oncogenic phenotype. More importantly, rescue experiments revealed that the oncogenic role of circPDE3B in ESCC is partly dependent on the miR-4766-5p/LAMA1 axis. Furthermore, bioinformatics analysis combined with validation experiments showed that epithelial-mesenchymal transition (EMT) activation was involved in the oncogenic functions of the circPDE3B–miR-4766-5p/LAMA1 axis in ESCC. Taken together, we demonstrate for the first time that the circPDE3B/miR-4766-5p/LAMA1 axis functions as an oncogenic factor in promoting ESCC cell proliferation, migration, and invasion by inducing EMT, implying its potential prognostic and therapeutic significance in ESCC.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joshua Miguel C. Danac ◽  
Reynaldo L. Garcia

AbstractCircular RNAs have emerged as functional regulatory molecules whose aberrant expression has been linked to diverse pathophysiological processes. Here, we report that circPVT1 interferes with let-7 binding to NRAS, confirming this axis as one route by which circPVT1 can instigate an oncogenic program in A549 lung cancer cells and HCT116 colorectal cancer cells. CircPVT1 knockdown significantly reduced NRAS levels and attenuated cancer hallmark phenotypes such as proliferation, migration, resistance to apoptosis, cytoskeletal disorganization, and epithelial-mesenchymal transition. The effects of circPVT1 knockdown were at least partially rescued by blocking binding of let-7 to NRAS 3′UTR with a target protector, suggesting that a circPVT1/let-7/NRAS axis exists and acts in cells to reverse NRAS downregulation and favor oncogenicity. While the phenotypic effects of circPVT1 knockdown may be attributable to the global action of circPVT1, the target protection assays resolved the relative contribution of the circPVT1/let-7/NRAS axis specifically.


Oncogene ◽  
2021 ◽  
Vol 40 (17) ◽  
pp. 3164-3179
Author(s):  
Yang Liu ◽  
Tianchi Tang ◽  
Xiaosheng Yang ◽  
Peng Qin ◽  
Pusen Wang ◽  
...  

AbstractPancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies and rapidly progressive diseases. Exosomes and long noncoding RNAs (lncRNAs) are emerging as vital mediators in tumor cells and their microenvironment. However, the detailed roles and mechanisms of exosomal lncRNAs in PDAC progression remain unknown. Here, we aimed to clarify the clinical significance and mechanisms of exosomal lncRNA 01133 (LINC01133) in PDAC. We analyzed the expression of LINC01133 in PDAC and found that exosomal LINC01133 expression was high and positively correlated with higher TNM stage and poor overall survival rate of PDAC patients. Further research demonstrated that Periostin could increase exosome secretion and then enhance LINC01133 expression. In addition, Periostin increased p-EGFR, p-Erk, and c-myc expression, and c-myc could bind to the LINC01133 promoter region. These findings suggested that LINC01133 can be regulated by Periostin via EGFR pathway activity. We also observed that LINC01133 promoted the proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) of pancreatic cancer cells. We subsequently evaluated the effect of LINC01133 on the Wnt/β-catenin pathway and confirmed that LINC01133 can interact with Enhancer Of Zeste Homolog 2 (EZH2) and then promote H3K27 trimethylation. This can further silence AXIN2 and suppress GSK3 activity, ultimately activating β-catenin. Collectively, these data indicate that exosomal LINC01133 plays an important role in pancreatic tumor progression, and targeting LINC01133 may provide a potential treatment strategy for PDAC.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jiabin Yu ◽  
Li Yang ◽  
Hongting Lu

AbstractMalignant tumors are one of the fatal diseases that threaten children’s physical and mental health and affect their development. Research has shown that the occurrence and development of malignant tumors are associated with the abnormal expression and regulation of genes. Circular RNAs (circRNAs) are noncoding RNAs that have a closed circular structure, with a relatively stable expression, and do not undergo exonuclease-mediated degradation readily. Recent studies have shown that circRNA plays an important role in the occurrence, metastasis, and invasion of solid malignant tumors (SMTs) in children. Thus, circRNA is being considered as a breakthrough in the treatment of SMTs in children. In this review, we describe the functions and mechanisms of circRNAs involved in SMTs in children oncogenesis, and summarize the roles of circRNAs in regulating cell proliferation, cell apoptotic death, the cell cycle, cell migrative and invasive ability, epithelial-mesenchymal transition (EMT), cancer stem cells and drug resistance in SMTs in children. In addition, we also discuss the role of circRNAs in the early diagnosis, pathological grading, targeted therapy, and prognosis evaluation of common SMTs in children. CircRNAs are likely to provide a novel direction in therapy in SMTs of children.


2019 ◽  
Vol 5 (4) ◽  
pp. 53 ◽  
Author(s):  
Xiao ◽  
Humphries ◽  
Yang ◽  
Wang

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that downregulate target gene expression by imperfect base-pairing with the 3′ untranslated regions (3′UTRs) of target gene mRNAs. MiRNAs play important roles in regulating cancer cell proliferation, stemness maintenance, tumorigenesis, cancer metastasis, and cancer therapeutic resistance. While studies have shown that dysregulation of miRNA-205-5p (miR-205) expression is controversial in different types of human cancers, it is generally observed that miR-205-5p expression level is downregulated in breast cancer and that miR-205-5p exhibits a tumor suppressive function in breast cancer. This review focuses on the role of miR-205-5p dysregulation in different subtypes of breast cancer, with discussions on the effects of miR-205-5p on breast cancer cell proliferation, epithelial–mesenchymal transition (EMT), metastasis, stemness and therapy-resistance, as well as genetic and epigenetic mechanisms that regulate miR-205-5p expression in breast cancer. In addition, the potential diagnostic and therapeutic value of miR-205-5p in breast cancer is also discussed. A comprehensive list of validated miR-205-5p direct targets is presented. It is concluded that miR-205-5p is an important tumor suppressive miRNA capable of inhibiting the growth and metastasis of human breast cancer, especially triple negative breast cancer. MiR-205-5p might be both a potential diagnostic biomarker and a therapeutic target for metastatic breast cancer.


2020 ◽  
Vol 29 ◽  
pp. 096368972092998 ◽  
Author(s):  
Chuang Du ◽  
Yan Wang ◽  
Yingying Zhang ◽  
Jianhua Zhang ◽  
Linfeng Zhang ◽  
...  

Triple-negative breast cancer (TNBC) is one of the most aggressive cancer types with high recurrence, metastasis, and drug resistance. Recent studies report that long noncoding RNAs (lncRNAs)-mediated competing endogenous RNAs (ceRNA) play an important role in tumorigenesis and drug resistance of TNBC. Although elevated lncRNA DLX6 antisense RNA 1 (DLX6-AS1) has been observed to promote carcinogenesis in various cancers, the role in TNBC remained unclear. In this study, expression levels of DLX6-AS1 were increased in TNBC tissues and cell lines when compared with normal tissues or breast fibroblast cells which were determined by quantitative real-time PCR (RT-qPCR). Then, CCK-8 assay, cell colony formation assay and western blot were performed in CAL-51 cells transfected with siRNAs of DLX6-AS1 or MDA-MB-231 cells transfected with DLX6-AS1 over expression plasmids. Knock down of DLX6-AS1 inhibited cell proliferation, epithelial-mesenchymal transition (EMT), decreased expression levels of BCL2 apoptosis regulator (Bcl-2), Snail family transcriptional repressor 1 (Snail) as well as N-cadherin and decreased expression levels of cleaved caspase-3, γ-catenin as well as E-cadherin, while up regulation of DLX6-AS1 had the opposite effect. Besides, knockdown of DLX6-AS1 in CAL-51 cells or up regulation of DLX6-AS1 in MDA-MB-231 cells also decreased or increased cisplatin resistance of those cells analyzed by MTT assay. Moreover, by using dual luciferase reporter assay, RNA immunoprecipitation and RNA pull down assay, a ceRNA which was consisted by lncRNA DLX6-AS1, microRNA-199b-5p (miR-199b-5p) and paxillin (PXN) was identified. And DLX6-AS1 function through miR-199b-5p/PXN in TNBC cells. Finally, results of xenograft experiments using nude mice showed that DLX6-AS1 regulated cell proliferation, EMT and cisplatin resistance by miR-199b-5p/PXN axis in vivo. In brief, DLX6-AS1 promoted cell proliferation, EMT, and cisplatin resistance through miR-199b-5p/PXN signaling in TNBC in vitro and in vivo.


2020 ◽  
Author(s):  
Kebin Zheng ◽  
Haipeng Xie ◽  
Xiaosong Wu ◽  
Xichao Wen ◽  
Zhaomu Zeng ◽  
...  

Abstract BackgroundIncreasing studies have revealed that circular RNAs (CircRNAs) make great contribution to regulating tumor progression. Therefore, we intended to explore the expression characteristics, function, and related mechanisms of a novel type of circRNA, PIP5K1A in glioma. MethodsFirstly, RT-PCR was carried out to examine CircPIP5K1A expression in glioma tissues and adjacent normal tissues, and the correlation between CircPIP5K1A level and the clinical pathological indicators of glioma was analyzed. Then, the CircPIP5K1A expression in various glioma cell lines was detected, and a cell model of CircPIP5K1A overexpression and knockdown was constructed. Subsequently, cell proliferation and viability were detected by CCK8 method and BrdU staining, apoptosis was detected by flow cytometry, and cell invasion was examined by Transwell assay. The expression of TCF12, PI3K/AKT pathway apoptotic related proteins (including Caspase3, Bax and Bcl2) and epithelial-mesenchymal transition (EMT) markers (including E-cadherin, Vimentin and N-cadherin) by western blot or RT-PCR. ResultsThe results manifested that CircPIP5K1A was obviously upregulated in glioma tissues (compared with that in normal adjacent tissues), and overexpressed CircPIP5K1A was distinctly related to glioma volume and histopathological grade. Functionally, overexpressing CircPIP5K1A notably elevated the proliferation, invasion, EMT of glioma cells, and inhibited apoptosis both in vivo and in vitro. Besides, CircPIP5K1A also upregulated TCF12 and PI3K/AKT pathway activation. Bioinformatics analysis testified that miR-515-5p was a common target of CircPIP5K1A and TCF12, while dual luciferase reporter assay and RNA immunocoprecipitation (RIP) experiment further confirmed that CircPIP5K1A targeted miR-515-5p, which bound the 3'-untranslated region (UTR) of TCF12. ConclusionsAltogether, the study illustrated that CircPIP5K1A is a potential prognostic marker in glioma and regulates the development of glioma through the modulating miR-515-5p mediated TCF12/PI3K/AKT axis.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yan Zhang ◽  
Xianwu Chen ◽  
Juntao Lin ◽  
Xiaodong Jin

AbstractBladder cancer (BCa) is one of the 10 most common cancers with high morbidity and mortality worldwide. Long noncoding RNAs (lncRNAs), a large class of noncoding RNA transcripts, consist of more than 200 nucleotides and play a significant role in the regulation of molecular interactions and cellular pathways during the occurrence and development of various cancers. In recent years, with the rapid advancement of high-throughput gene sequencing technology, several differentially expressed lncRNAs have been discovered in BCa, and their functions have been proven to have an impact on BCa development, such as cell growth and proliferation, metastasis, epithelial-mesenchymal transition (EMT), angiogenesis, and drug-resistance. Furthermore, evidence suggests that lncRNAs are significantly associated with BCa patients’ clinicopathological characteristics, especially tumor grade, TNM stage, and clinical progression stage. In addition, lncRNAs have the potential to more accurately predict BCa patient prognosis, suggesting their potential as diagnostic and prognostic biomarkers for BCa patients in the future. In this review, we briefly summarize and discuss recent research progress on BCa-associated lncRNAs, while focusing on their biological functions and mechanisms, clinical significance, and targeted therapy in BCa oncogenesis and malignant progression.


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