Circ-RNF111 aggravates the malignancy of gastric cancer through miR-876-3p-dependent regulation of KLF12

Circ_0007432 promotes non-small cell lung cancer progression and macrophage M2 polarization through SRSF1/KLF12 axis

Circular RNAs (circRNAs) plays critical roles in non-small cell lung cancer (NSCLC) development. Herein, we illustrated the effects of circ_0007432 on malignant features of NSCLC. We found that circ_0007432 played a promoting role in NSCLC progression, lying in accelerating cell viability, migration and invasion of NSCLC cells, promoting M2 macrophage polarization, suppressing cell apoptosis of NSCLC cells, and enhancing tumor growth in vivo. Mechanistically, the interactions among circ_0007432, SRSF1, KLF12, and IL-8 were validated by RNA-binding protein immunoprecipitation (RIP), electrophoretic mobility shift assay (EMSA), RNA pull-down, dual luciferase reporter assay and chromatin immunoprecipitation (ChIP) assays. Circ_0007432 upregulated KLF12 by recruiting SRSF1. KLF12 facilitated IL-8 expression and release by binding to IL-8 promoter. Furthermore, the role of circ_0007432/SRSF1/KLF12/IL-8 axis in malignant phenotypes of tumor cells or macrophage polarization was investigated using rescue experiments. In conclusion, circ_0007432 bound with SRSF1 to stabilize KLF12 and then promote IL-8 release, thus promoting malignant behaviors of NSCLC cells and M2 macrophage polarization.

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

Circ-RNF111 Promotes Proliferation of Ovarian Cancer Cell SKOV-3 by Targeting the MiR-556-5p/CCND1 Axis

The aim of this study was to investigate the role and mechanism of circ-RNF111 in the human ovarian cancer cell line SKOV-3. First, qRT-PCR was used to detect circ-RNF111 and miR-556-5p expression levels in human normal ovarian epithelial cells IOSE80 and human ovarian cancer cells SKOV-3. CCK-8 and colony formation assays were adopted to determine the proliferation rate and cell viability of SKOV-3 cells, respectively. Additionally, in an attempt to reveal the mechanism of circ-RNF111, we predicted the targeting relationship between miR-556-5p and circ-RNF111 as well as miR-556-5p and CCND1 using the circinteractome and TargetScan databases, respectively, and validated their relationship by dual-luciferase reporter assay. The protein expression levels of CCND1 in SKOV-3 cells were detected by Western blot. Based on the above experiments, the expression of circ-RNF111 was found to be up-regulated in SKOV-3, and the knockdown of circ-RNF111 significantly inhibited the proliferation and viability of SKOV-3 cells. Then we confirmed that circ-RNF111 sponged miR-556-5p in SKOV-3 cells to up-regulate CCND1 expression. In addition, simultaneous inhibition of miR-556-5p or overexpression of CCND1 in SKOV-3 cells with knockdown of circ-RNF111 reversed the inhibitory effect of knockdown of circ-RNF111 on the protein expression level of CCND1, cell proliferation rate, and cell viability. In summary, circ-RNF111 promotes the proliferation of SKOV-3 cells by targeting the miR-556-5p/CCND1 axis. Circ-RNF111 may serve as a potential target for ovarian cancer therapy.

Metformin suppresses proliferation and glycolysis of gastric cancer by modulating ADAMTS12

BACKGROUND

Gastric cancer (GC) is a common malignancy with its morbidity increasing worldwide. Hence, it is imperative to develop effective treatments. Studies have shown that metformin has potential antitumor effects. The objective of this study was to probe the antitumor mechanism of metformin in GC.

METHODS

The expression of ADAMTS12 in GC tissues and its enrichment pathways were analyzed by bioinformatics methods. ADAMTS12 expression in GC cells was assessed by qRT-PCR. Cell viability and proliferation were analyzed by CCK-8 and colony formation assays, respectively. Extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of GC cells in different treatment groups were analyzed by Seahorse XP 96, and glycolysis metabolites were detected by corresponding kits. Western blot was employed to analyze the level of glycolysis pathway related protein HK-2, and cell functional assays were conducted to verify the functions of metformin on GC cells. A xenograft model was constructed to validate the inhibitory role of metformin in GC.

RESULTS

ADAMTS12 expression was elevated in GC tissues/cells and concentrated in glycolysis pathway. Cell functional assays found that ADAMTS12 promoted the proliferation and glycolysis of GC cells. Rescue experiments showed that metformin could reduce the promoting effect of ADAMTS12 overexpression on the proliferation and glycolysis of GC cells. In vivo studies confirmed that metformin suppressed the proliferation and glycolysis process via ADAMTS12 in GC cells.

CONCLUSION

Metformin can repress the proliferation and glycolysis of GC cells via ADAMTS12. The results suggest the potential of ADAMTS12 being a target for the metformin therapy of GC.

LINC00460 knockdown sensitizes cervical cancer to cisplatin by downregulating TGFBI

The acquired resistance of cancer to cisplatin (DDP) limits the efficacy of chemotherapy. The prognostic value of long noncoding RNA (lncRNA) LINC00460 has been reported in cervical cancer. However, its effect on DDP sensitivity in cervical cancer remains poorly understood. In present study, LINC00460 was screened out through bioinformatics analysis. The expression levels of mRNAs and proteins were measured by reverse transcription-quantitative PCR (RT-qPCR) or western blot analysis. The sensitivity to DDP was investigated using an CCK8 assay. Cell apoptosis was determined by flow cytometry. The differentially expressed genes that were associated with the poor prognosis of cervical cancer were screened, and their correlations with LINC00460 expression were explored using Pearson's correlation analysis. Tumor xenograft model was used to assess the effect of LINC00460 knockdown on DDP sensitivity in vivo. The interaction between miR-338-3p and LINC00460 or transforming growth factor β-induced protein (TGFBI) was confirmed by RNA immunoprecipitation (RIP) and luciferase reporter assays. LINC00460 expression was increased in cervical cancer tissues and cells. High expression of LINC00460 was associated with dismal prognosis in cervical cancer patients. Silencing of LINC00460 increased drug sensitivity and induced apoptosis in DDP-resistant-cervical cancer cells. LINC00460 knockdown enhanced DDP sensitivity in cervical cancer cells largely by downregulating TGFBI expression. LINC00460 knockdown enhanced the sensitivity of cervical cancer to DDP in vivo, and this effect was partly mediated by the downregulation of TGFBI. LINC00460 positively regulated TGFBI expression, possibly by acting as a sponge of miR-338-3p. LINC00460 knockdown contributed to DDP sensitivity of cervical cancer by downregulating TGFBI, providing a novel mechanism underlying the acquisition of DDP sensitivity.

CircRNF111 Contributes to Adipocyte Differentiation by Elevating PPARγ Expression via miR-27a-3p

The content and distribution of adipocytes is an important factor that affects meat quality. Previous studies showed that circRNAs are involved in various physiological processes. Nevertheless, more research is needed to investigate the function of circRNAs in adipogenesis. The present study examines the effects of circRNF111 on adipogenesis of bovine preadipocyte and aims to elucidate the underlying molecular mechanisms. In our study, the sequence signature of circRNF111 was identified using bioinformatics, RNA-FISH, and sequencing. Mechanistically, knockdown or exogenous expression of circRNF111 in preadipocytes was done to prove the functional significance of circRNF111. Combined with bioinformatics, a dual fluorescein reporter system, and immunoprecipitation, the interaction between circRNF111, miR-27a-3p, and the target gene PPARγ was verified. The results reveal that circRNF111 is positively correlated with adipocyte differentiation. The newly identified bovine circRNF111 functions as a miR-27a-3p sponge to rescue the inhibitory effect of miR-27a-3p on the PPARγ gene, thereby promoting adipogenesis.

Circ_0084188 promotes colorectal cancer progression by sponging miR-654-3p and regulating kruppel-like factor 12

To investigate the biological role and mechanism of circ_0084188 in colorectal cancer (CRC). Real-time quantitative polymerase chain reaction and western blot assay were used to detect RNA levels and protein levels in CRC cell lines (HCT116 and SW480), respectively. Cell proliferation was evaluated by Cell Counting Kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, and colony formation assays. Cell apoptosis was determined using flow cytometry. Cell migration and invasion were measured by transwell assay. Sphere formation efficiency was determined by sphere formation assay. The interaction between microRNA-654-3p (miR-654-3p) and circ_0084188 or Kruppel-like factor 12 (KLF12) was confirmed by a dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Xenograft in CRC mice model was utilized for exploring the role of circ_0084188 in vivo.Circ_0084188 was overexpressed in CRC tissues and cells. Circ_0084188 silencing suppressed cell proliferation, migration, invasion, and stemness and induced apoptosis in CRC cells. Circ_0084188 acted as a sponge for miR-654-3p, and circ_0084188 regulated CRC cell behaviors via sponging miR-654-3p. Moreover, KLF12 was a target of miR-654-3p, and miR-654-3p overexpression inhibited the malignant behaviors of CRC cells by downregulating KLF12. Mechanically, circ_0084188 sponged miR-654-3p to regulate KLF12 expression in CRC cells. In addition, circ_0084188 downregulation inhibited tumor growth in vivo.Circ_0084188 knockdown might repress CRC progression partially via regulating the miR-654-3p/KLF12 axis, providing a novel insight into the pathogenesis of CRC.

Zinc Finger Proteins in the War on Gastric Cancer: Molecular Mechanism and Clinical Potential

According to the 2020 global cancer data released by the World Cancer Research Fund (WCRF) International, gastric cancer (GC) is the fifth most common cancer worldwide, with yearly increasing incidence and the second-highest fatality rate in malignancies. Despite the contemporary ambiguous molecular mechanisms in GC pathogenesis, numerous in-depth studies have demonstrated that zinc finger proteins (ZFPs) are essential for the development and progression of GC. ZFPs are a class of transcription factors with finger-like domains that bind to Zn²⁺ extensively and participate in gene replication, cell differentiation and tumor development. In this review, we briefly outline the roles, molecular mechanisms and the latest advances in ZFPs in GC, including eight principal aspects, such as cell proliferation, epithelial-mesenchymal transition (EMT), invasion and metastasis, inflammation and immune infiltration, apoptosis, cell cycle, DNA methylation, cancer stem cells (CSCs) and drug resistance. Intriguingly, the myeloid zinc finger 1 (MZF1) possesses reversely dual roles in GC by promoting tumor proliferation or impeding cancer progression via apoptosis. Therefore, a thorough understanding of the molecular mechanism of ZFPs on GC progression will pave the solid way for screening the potentially effective diagnostic indicators, prognostic biomarkers and therapeutic targets of GC.

SP and KLF Transcription Factors in Cancer Metabolism

Tumor development and progression depend on reprogramming of signaling pathways that regulate cell metabolism. Alterations to various metabolic pathways such as glycolysis, oxidative phosphorylation, lipid metabolism, and hexosamine biosynthesis pathway are crucial to sustain increased redox, bioenergetic, and biosynthesis demands of a tumor cell. Transcription factors (oncogenes and tumor suppressors) play crucial roles in modulating these alterations, and their functions are tethered to major metabolic pathways under homeostatic conditions and disease initiation and advancement. Specificity proteins (SPs) and Krüppel-like factors (KLFs) are closely related transcription factors characterized by three highly conserved zinc fingers domains that interact with DNA. Studies have demonstrated that SP and KLF transcription factors are expressed in various tissues and regulate diverse processes such as proliferation, differentiation, apoptosis, inflammation, and tumorigenesis. This review highlights the role of SP and KLF transcription factors in the metabolism of various cancers and their impact on tumorigenesis. A better understanding of the role and underlying mechanisms governing the metabolic changes during tumorigenesis could provide new therapeutic opportunities for cancer treatment.

Silencing of circCYP51A1 represses cell progression and glycolysis by regulating miR-490-3p/KLF12 axis in osteosarcoma under hypoxia

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CircCYP51A1 was up-regulated in osteosarcoma cells under hypoxia.

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CircCYP51A1 mediated KLF12 expression through sponging miR-490-3p.

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Under hypoxia condition, circCYP51A1 knockdown inhibited cell progression and glycolysis by regulating miR-490-3p/ KLF12 axis.

Background

Methods

Results

Conclusion

Hsa_circ_0001982 promotes the proliferation, invasion, and multidrug resistance of osteosarcoma cells

Background

Osteosarcoma (OS) is the most common bone cancer mostly seen in people aged 10–25 years. This research aims to clarify the function of hsa_circ_0001982 in osteosarcoma (OS) and its effect on drug resistance, preliminarily exploring its mechanism.

Methods

The expression of hsa_circ_0001982 and miR‐143 in OS clinical tissues and cells was detected by real‐time fluorescence quantitative polymerase chain reaction (qRT‐PCR), MTT, colony formation assay, and transwell assay assessed cell proliferation, colony formation, migration, and invasion, respectively. The targeted relationship of hsa_circ_0001982 and miR‐143 was verified by a dual‐luciferase reporter assay.

Result

The expression of hsa_circ_0001982 was significantly increased in OS tissues and cells (MG63), as in well as chemoresistant OS tissues and cells (MG63/Dox). Overexpression of hsa_circ_0001982 promoted proliferation, colony formation, migration, invasion, and multidrug resistance in MG63 cells. By contrast, knockdown of hsa_circ_0001982 markedly reduced the resistance of MG63/Dox cells to doxorubicin (IC50 evidently reduced). Bioinformatic prediction showed that miR‐143 was a target miRNA of hsa_circ_0001982, and a dual‐luciferase reporter assay proved this. Further experiments revealed that miR‐143 expression was notably downregulated in OS tissues, chemoresistant OS tissues, and MG63/Dox cells. Moreover, miR‐143 was negatively correlated with hsa_circ_0001982 in OS cells and tissues.

Conclusion

The regulation of malignant behaviors such as proliferation, invasion, migration, and multidrug resistance of OS cells by hsa_circ_0001982 may be achieved by targeting miR‐143. Moreover, hsa_circ_0001982 is a potential target for early diagnosis and targeted therapy of OS.

CircRNAs: promising factors for regulating angiogenesis in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers in the world. The incidence rate of cancer is high. The overall response to traditional treatment methods such as surgery, radiotherapy, and chemotherapy is not very satisfactory. Therefore, finding new therapeutic targets is very important for improving CRC treatment. In recent reports, the role of circRNAs in regulating colorectal angiogenesis has been gradually revealed. CircRNAs can indirectly act on angiogenesis pathways and regulate the expression of growth factors such as vascular endothelial growth factor (VEGF). CircRNAs are endogenous noncoding RNAs formed by pre-mRNAs through exon circular splicing. The covalent closed-loop structure makes these RNAs highly conserved and stable. CircRNAs have been found in human plasma, serum, urine, and other body fluids. Their highly conserved characteristics play important roles in many biological activities. CircRNAs can participate in the progression of many diseases by sponging miRNAs, interacting with proteins, and regulating transcription. Angiogenesis can provide nutrients and oxygen for tumour proliferation and metastasis. Angiogenesis is an important sign of the formation of the tumour microenvironment. Here, we will summarize the role of the latest circRNAs in the mechanism of angiogenesis in CRC and provide potential therapeutic targets for clinical treatment.

Construction of a circRNA-miRNA-mRNA network based on differentially co-expressed circular RNA in gastric cancer tissue and plasma by bioinformatics analysis

Background

Increasing evidence implicates circular RNAs (circRNAs) have been involved in human cancer progression. However, the mechanism remains unclear. In this study, we identified novel circRNAs related to gastric cancer and constructed a circRNA-miRNA-mRNA network.

Methods

Microarray datasets GSE83521 and GSE93541 were obtained from the Gene Expression Omnibus (GEO). Then, we used computational biology to identify circRNAs that were differentially expressed in both GC tissue and plasma compared to normal controls; then, we detected the expression of the selected circRNAs in gastric cell lines by quantitative real-time polymerase chain reaction (qRT-PCR). We also identified circRNA-related candidate miRNAs and their target genes with online tools. Combining the predicted miRNAs and target mRNAs, a competing endogenous RNA regulatory network was established. Functional and pathway enrichment analyses were performed, and interactions between proteins were predicted by using String and Cytoscape. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to elucidate the possible functions of these differentially expressed circRNAs. The regulatory network constructed using the microarray datasets (GSE83521 and GSE93541) contained three differentially co-expressed circRNAs (DECs). A circRNA-miRNA-mRNA network was constructed based on 3 circRNAs, 43 miRNAs and 119 mRNAs.

Results

GO and KEGG analysis showed that the regulation of apoptotic signaling pathway and PI3K−Akt signaling pathway were highest degrees of enrichment respectively. We established a protein-protein interaction (PPI) network consisting of 165 nodes and 170 edges and identified hub genes by using MCODE plugin in Cytoscape. Furthermore, a core circRNA-miRNA-mRNA network was constructed based on hub genes. Hsa_circ_0001013 was finally determined to play an important role in the pathogenesis of GC according to the core circRNA-miRNA-mRNA network.

Conclusions

We propose a new circRNA-miRNA-mRNA network that is associated with the pathogenesis of GC. The network may become a new molecular biomarker and could be used to develop potential therapeutic strategies for gastric cancer.