Circ-CCS is identified as a cancer-promoting circRNA in lung cancer partly by regulating the miR-383/E2F7 axis

Advanced approaches of the use of circRNAs as a replacement for cancer therapy

Cancer is a broad name for a group of diseases in which abnormal cells grow out of control and are characterized by their complexity and recurrence. Although there has been progress in cancer therapy with the entry of precision medicine and immunotherapy, cancer incidence rates have increased globally. Non-coding RNAs in the form of circular RNAs (circRNAs) play crucial roles in the pathogenesis, clinical diagnosis, and therapy of different diseases, including cancer. According to recent studies, circRNAs appear to serve as accurate indicators and therapeutic targets for cancer treatment. However, circRNAs are promising candidates for cutting-edge cancer therapy because of their distinctive circular structure, stability, and wide range of capabilities; many challenges persist that decrease the applications of circRNA-based cancer therapeutics. Here, we explore the roles of circRNAs as a replacement for cancer therapy, highlight the main challenges facing circRNA-based cancer therapies, and discuss the key strategies to overcome these challenges to improve advanced innovative therapies based on circRNAs with long-term health effects.

Novel genome-wide DNA methylation profiling reveals distinct epigenetic landscape, prognostic model and cellular composition of early-stage lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) has been a leading cause of cancer-related mortality worldwide. Early intervention can significantly improve prognosis. DNA methylation could occur in the early stage of tumor. Comprehensive understanding the epigenetic landscape of early-stage LUAD is crucial in understanding tumorigenesis.

METHODS

Enzymatic methyl sequencing (EM-seq) was performed on 23 tumors and paired normal tissue to reveal distinct epigenetic landscape, for compared with The Cancer Genome Atlas (TCGA) 450K methylation microarray data. Then, an integrative analysis was performed combined with TCGA LUAD RNA-seq data to identify significant differential methylated and expressed genes. Subsequently, the prognostic risk model was constructed and cellular composition was analyzed.

RESULTS

Methylome analysis of EM-seq comparing tumor and normal tissues identified 25 million cytosine-phosphate-guanine (CpG) sites and 30,187 differentially methylated regions (DMR) with a greater number of untraditional types. EM-seq identified a significantly higher number of CpG sites and DMRs compared to the 450K microarray. By integrating the differentially methylated genes (DMGs) with LUAD-related differentially expressed genes (DEGs) from the TCGA database, we constructed prognostic model based on six differentially methylated-expressed genes (MEGs) and verified our prognostic model in GSE13213 and GSE42127 dataset. Finally, cell deconvolution based on the in-house EM-seq methylation profile was used to estimate cellular composition of early-stage LUAD.

CONCLUSIONS

This study firstly delves into novel pattern of epigenomic DNA methylation and provides a multidimensional analysis of the role of DNA methylation revealed by EM-seq in early-stage LUAD, providing distinctive insights into its potential epigenetic mechanisms.

Circ-10720 as a ceRNA adsorbs microRNA-1238 and modulates ZEB2 to boost NSCLC development by activating EMT

BACKGROUND

Circular RNAs (circRNAs) are critical regulators in the progression of tumors. This experimental design aimed to explore the mechanism of circ-10720 in non-small cell lung cancer (NSCLC).

METHODS

We used RT-qPCR to measure circ-10720 expression in clinical samples and analyzed its relationship with the clinicopathological characteristics of NSCLC patients. The expression levels of microRNA-1238 (miR-1238) and Zinc Finger E-box-binding Homeobox 2 (ZEB2) in clinical samples were detected by RT-qPCR. NSCLC cells were transfected with relevant plasmids or sequences. Circ-10720, miR-1238, and ZEB2 expressions in cells were analyzed via RT-qPCR or western blot. Cell proliferation, apoptosis, migration, and invasion were assessed with CCK-8, flow cytometry, and transwell assay, respectively. The protein expression of ZEB2 and epithelial-mesenchymal transition (EMT)-related markers (E-cadherin, Vimentin, N-cadherin) were detected via western blot. Xenograft assay was used to determine the effect of circ-10720 on NSCLC in vivo. Circ-10720 and ZEB2 expressions in tumors were detected using RT-qPCR or Western blot. Immunohistochemistry was used to evaluate E-cadherin and N-cadherin expression in tumors. Finally, the binding relationship between miR-1238 with circ-10720 or ZEB2 was verified by the bioinformatics website, dual luciferase reporter assay, RNA pull-down assay, and RIP assay.

RESULTS

Circ-10720 was upregulated in NSCLC and correlated with TNM stage of NSCLC patients. MiR-1238 was lowly expressed but ZEB2 was highly expressed in NSCLC. Circ-10720 silencing suppressed the proliferation, metastasis, and EMT of NSCLC cells. Mechanically, circ-10720 was a competitive endogenous RNA (ceRNA) for miR-1238, and ZEB2 was a target of miR-1238. circ-10720-modulated ZEB2 via competitively binding with miR-1238 to control NSCLC progression. In addition, circ-10720 knockdown suppressed tumor growth in vivo.

CONCLUSIONS

Circ-10720 acts as a ceRNA to adsorb miR-1238 and modulate ZEB2 to facilitate the proliferation, migration, invasion, and EMT of NSCLC cells.

Copper metabolism and cuproptosis in human malignancies: Unraveling the complex interplay for therapeutic insights

Copper, a vital trace element, orchestrates diverse cellular processes ranging from energy production to antioxidant defense and angiogenesis. Copper metabolism and cuproptosis are closely linked in the context of human diseases, with a particular focus on cancer. Cuproptosis refers to a specific type of copper-mediated cell death or copper toxicity triggered by disruptions in copper metabolism within the cells. This phenomenon encompasses a spectrum of mechanisms, such as oxidative stress, mitochondrial dysfunction, endoplasmic reticulum stress, and perturbations in metal ion equilibrium. Mechanistically, cuproptosis is driven by copper binding to the lipoylated enzymes within the tricarboxylic acid (TCA) cycle. This interaction participates in protein aggregation and proteotoxic stress, ultimately culminating in cell death. Targeting copper metabolism and its associated pathways in cancer cells hold therapeutic potential by selectively targeting and eliminating cancerous cells. Strategies to modulate copper levels, enhance copper excretion, or interfere with cuproptotic pathways are being explored to identify novel therapeutic targets for cancer therapy and improve patient outcomes. Understanding the relationship between cuproptosis and copper metabolism in human malignancies remains an active area of research. This review provides a comprehensive overview of the association among copper metabolism, copper homeostasis, and carcinogenesis, explicitly emphasizing the cuproptosis mechanism and its implications for cancer pathogenesis. Additionally, we emphasize the therapeutic aspects of targeting copper and cuproptosis for cancer treatment.

Circ_0006324 regulates cell proliferation, cell-cycle progression, apoptosis, and glycolysis of non-small cell lung cancer cells through miR-496/TRIM59 axis

Increasing evidence suggests that circular RNA (circRNA) plays an important role in non-small cell lung cancer (NSCLC) progression. This study aimed to investigate the role and potential molecular mechanism of circ_0006324 in NSCLC. The expression levels of circ_0006324, miR-496, miR-488-5p, and tripartite motif-containing 59 (TRIM59) mRNA were determined by quantitative real-time polymerase chain reaction (PCR). 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay, EdU assay, and flow cytometry were carried out to evaluate cell proliferation and apoptosis. The extracellular acidification rate and lactic acid production were examined to assess cell glycolysis. Western blot assay was used to detect protein levels. The target relationship of circ_0006324/miR-496/TRIM59 axis was validated by RNA pull-down assay, dual luciferase reporter assay, and radio immunoprecipitation assay. Xenograft tumor assay was performed to reveal the function of circ_0006324 in vivo. Circ_0006324 was upregulated in NSCLC and related to tumor node metastasis stage and distant metastasis. Knockdown of circ_00006324 impeded NSCLC cell proliferation, glycolysis, and promoted cell apoptosis. MiR-496 was verified as a target of circ_0006324 and circ_00006324 mediated the altering of cell proliferation, apoptosis, and glycolysis of NSCLC cells through targeting miR-496. TRIM59 was verified as a target of miR-496, and circ_0006324 positively regulated TRIM59 expression by targeting miR-496. Overexpression of TRIM59 could reverse the effects of circ_0006324 silencing on the proliferation, apoptosis, and glycolysis of NSCLC cells. Circ_0006324 knockdown impeded NSCLC tumor growth in vivo. Circ_0006324 functioned as a tumor promoter in NSCLC to promote cell proliferation, cell cycle progression, and glycolysis and inhibit cell apoptosis via miR-496/TRIM59 axis.

CircRNAs and lung cancer: Insight into their roles in metastasis

Lung cancer is the leading cause of cancer-related mortality worldwide. A major contributing factor to the poor survival rates in lung cancer is the high prevalence of metastasis at the time of diagnosis. To address this critical issue, it is imperative to investigate the mechanisms underlying lung cancer metastasis. Circular RNAs (circRNAs), a distinct type of ribonucleic acid characterized by their unique circular structure, have been implicated in the progression of various diseases. Recent studies have highlighted the close association between circRNAs and the occurrence and development of lung cancer, particularly in relation to metastasis. In this review, we provide a concise overview of the expression patterns and prognostic significance of circRNAs in lung cancer. Additionally, we summarized the current understanding of the clinical relevance of circRNAs in lung cancer metastasis. Furthermore, we systematically focused on the roles of circRNAs in each step of lung cancer metastasis, reflecting the sequential progression of this process. Notably, circRNAs exhibit dual functionality in lung cancer metastasis, acting both as facilitators and inhibitors of metastatic processes. Given their potential, circRNAs hold promise as novel biomarkers and therapeutic targets for lung cancer metastasis, warranting further investigation.

Circ_0010235 confers cisplatin resistance in lung cancer by upregulating E2F7 through absorbing miR-379-5p

BACKGROUND

Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for lung cancer patients. Circular RNAs (circRNAs) have been revealed to participate in the chemoresistance in lung cancer. Hence, the role and mechanism of circ_0010235 in cisplatin resistance in lung cancer was investigated.

METHODS

Expression levels of circ_0010235, microRNA (miR)-379-5p and E2F transcription factor 7 (E2F7) were analyzed using quantitative reverse transcription PCR (qRT-PCR) and western blot. Cell DDP sensitivity, proliferation, apoptosis, invasion, and migration were detected by cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EDU) assay, flow cytometry and western blot, respectively. The binding interaction was verified using dual-luciferase reporter assay. A murine xenograft model was established to investigate effects in vivo.

RESULTS

Circ_0010235 was highly expressed in DDP-resistant lung cancer tissues and cells. Knockdown of circ_0010235 elevated DDP sensitivity, constrained proliferation, invasion and migration as well as fostered apoptosis in DDP-resistant lung cancer cells. Moreover, circ_0010235 silencing boosted DDP sensitivity and impeded tumor growth in lung cancer in vivo. Mechanistically, circ_0010235 acted as a sponge for miR-379-5p to elevate the expression of its target E2F7. Rescue experiments showed that miR-379-5p inhibition attenuated circ_0010235 knockdown-evoked reduction on DDP resistance of DDP-resistant cancer cells. In addition, miR-379-5p re-expression elevated DDP sensitivity and suppressed the malignant phenotype of DDP-resistant lung cancer cells through miR-379-5p.

CONCLUSION

Circ_0010235 knockdown reduced DDP resistance and tumor growth via miR-379-5p/ E2F7 axis in lung cancer, suggesting an effective therapeutic target for lung cancer patients.

The role of selected non-coding RNAs in the biology of non-small cell lung cancer

Lung cancer is the second most frequently diagnosed cancer worldwide and a leading cause of cancer-related deaths. Non-small cell lung carcinoma (NSCLC) represents 85% of all cases. Accumulating evidence highlights the outstanding role of non-coding RNA (ncRNA) in regulating the tumorigenesis process by modulating crucial signaling pathways. Micro RNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA) are either up- or downregulated in lung cancer patients and can promote or suppress the progression of the disease. These molecules interact with messenger RNA (mRNA) and with each other to regulate gene expression and stimulate proto-oncogenes or silence tumor suppressors. NcRNAs provide a new strategy to diagnose or treat lung cancer patients and multiple molecules have already been identified as potential biomarkers or therapeutic targets. The aim of this review is to summarize the current evidence on the roles of miRNA, lncRNA and circRNA in NSCLC biology and present their clinical potential.

Dexmedetomidine promotes ferroptotic cell death in gastric cancer via hsa_circ_0008035/miR-302a/E2F7 axis

Dexmedetomidine (DEX), a common anesthetic, has significant effects on the biological features of cancer cells. Although numerous studies have been published on the impact of DEX on the biological characteristics of GC cells, the mechanism remains unknown. This study aimed to explore the effect of DEX on the biological properties of GC cells. DEX suppressed the viability and increased the apoptosis of GC cells in vitro and inhibited tumor growth in vivo. Besides, DEX raised the levels of reactive oxygen species (ROS) and iron, but decreased the levels of glutathione (GSH), glutathione peroxidase 4 (GPX4), and solute carrier family 7 member 11 (SLC7A11) in GC cells, which were abolished by Ferrostatin-1 (the inhibitor of ferroptosis) treatment. In addition, the level of circ0008035 and E2F7 were downregulated, but miR-302a level was upregulated in DEX-treated GC cells. Circ0008035 increased the expression of E2F2 by acting as a sponge for miR-302a. Circ0008035 inhibited DEX-induced ferroptotic cell death in GC cells, which was reversed by miR-302a overexpression or E2F7 reduction. Taken together, DEX mediated ferroptotic cell death in GC through regulating the circ0008035/miR-302a/E2F7 axis, suggesting a feasible therapy option for GC.

LncRNA-UCA1 regulates lung adenocarcinoma progression through competitive binding to miR-383

The present study aimed to assess the role of the long non-coding RNA-urothelial cancer associated 1 (lncRNA-UCA1)/microRNA (miR)-383/vascular endothelial growth factor A (VEGFA) axis in regulating lung adenocarcinoma physiology through in vivo and in vitro experiments. The expression profile of lncRNA-UCA1 was analyzed by genome-wide analysis from GSE146459. The cell counting Kit-8, colony formation, wound healing and transwell assays were performed to evaluate the effects of lncRNA-UCA1 in vitro. In addition, luciferase reporter assays were performed to confirm the binding site. The expression levels of miR-383 and VEGFA in tumor cells were measured using reverse transcription-quantitative PCR. HCC-78 was also transfected with miR-383 mimics, inhibitors and siRNA-VEGFA before their viability was also assessed. Xenograft models were established in nude mice to investigate the tumor characteristics in vivo. The expression of lncRNA-UCA1 was significantly increased in tumor tissues and cells compared with adjacent tissues or HBE cells. Silencing lncRNA-UCA1 expression in cells resulted in a reduction in lung cancer cell viability. In addition, lncRNA-UCA1 silencing increased the expression of miR-383. Inhibiting miR-383 expression increased HCC-78 proliferation, migration and invasion, whilst reducing their apoptosis. miR-383 was shown to specifically target VEGFA to inhibit its expression at both the protein and mRNA levels. VEGFA knockdown resulted in a reduction in all aforementioned aspects of HCC-78 cell activity. In addition, inhibiting miR-383 expression led to larger tumor sizes in vivo. To conclude, the results of the study suggest that lncRNA-UCA1 can regulate the expression of miR-383 and, in turn, VEGFA.

CircKRT14 upregulates E2F3 by interacting with miR-1256 to act as an oncogenic factor in esophageal cancer

BACKGROUND

A growing number of studies have focused on the regulatory role of circular RNAs (circRNAs) in a variety of cancers. The purpose of this study was to investigate the effect of circRNA Keratin 14 (circKRT14) on the progression of esophageal cancer (EC).

METHODS

The levels of circKRT14, miR-1256 and E2F transcription factor 3 (E2F3) were analyzed by real-time quantitative polymerase chain reaction (qRT-PCR) and western blot. The circular structure of circKRT14 was confirmed by RNase R digestion assay. Cell apoptosis, migration and invasion were detected by flow cytometry and transwell assay. The protein levels of related factors were determined by western blot. The relationship between miR-1256 and circKRT14 or E2F3 was verified by dual-luciferase reporter assay. The in vivo function of circKRT14 was studied by xenograft tumor assay.

RESULTS

CircKRT14 was significantly increased in EC tissues and cells. CircKRT14 silencing inhibited EC cell proliferation, migration, and invasion, but promoted EC cell apoptosis in vitro. CircKRT1 acted as a sponge for miR-1256 in EC, and in-miR-1256 abolished the inhibitory effect of circKRT14 suppression on EC cell progression. E2F3 was a target of miR-1256 and functioned as an oncogene in EC cells. MiR-1256 curbed EC progression by downregulating E2F3. CircKRT14 could affect E2F3 expression by targeting miR-1256. CircKRT14 regulated EC progression in vivo through miR-1256/E2F3 axis.

CONCLUSIONS

These results uncovered that circKRT14 up-regulated the expression of E2F3 and promoted the malignant development of EC through sponging miR-1256.

Circ_0003570 Suppresses the progression of hepatocellular carcinoma through miR-182-5p/STARD13 regulatory axis

Background

Emerging evidence have revealed that circRNAs exert important biological effects in the development and progression of various diseases, including cancer. Our study aimed to elaborated the biological effects of hsa-circ_0003570 in hepatocellular carcinoma (HCC) development at the molecular level.

Results

The results of functional experiments showed that knockdown of circ_0003570 induced HCC cell growth, migration and invasion, whereas overexpression of circ_0003570 presented the opposite effects. In vivo experiments, xenograft tumors grown from circ-overexpressed cells had smaller tumor volume and weight than the control group. Further investigations suggested that circ_0003570 may function as a competing endogenous RNA via competitively binding miR-182-5p and thereby regulating the repression of downstream target gene STARD13, which were demonstrated by dual luciferase reporter assay and functional rescued experiments.

Conclusions

Taken together, circ_0003570 suppresses the development of HCC by modulating miR-182-5p/STARD13 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12575-022-00176-w.

Circular RNA Controls Tumor Occurrence and Development via Cell Cycle Regulation

Circular RNAs (circRNAs) participate in the occurrence and development of various diseases through different mechanisms, such as by acting as a microRNA (miRNA) sponge, interacting with RNA-binding proteins, and regulating gene transcription and protein translation. For example, the abnormal expression of specific circRNAs in tumor cells can alter key regulatory factors and the cell cycle network, resulting in cell cycle disorders and the development and metastasis of tumors. Here, we summarize the mechanisms involved in the circRNA-mediated processes that lead to uncontrolled cell cycle and tumor cell proliferation. Extensive studies investigating the abnormal expression of circRNAs in different cancer types have been conducted. The unique characteristics of circRNAs and their ability to regulate the cell cycle through diverse mechanisms is extremely valuable in tumor diagnosis, treatment, and prognosis. Our review may assist in further understanding the circRNA-mediated regulation of the cell cycle in tumors and provide insights for research on circRNA-based therapeutic strategies and biological diagnosis for cancer.

NLR family CARD domain containing 5 promotes hypoxia-induced cancer progress and carboplatin resistance by activating PI3K/AKT via carcinoembryonic antigen related cell adhesion molecule 1 in non-small cell lung cancer

It is well known that non-small cell lung cancer (NSCLC) is a malignant tumor with high incidence in the world. We aimed to clarify a possible target and identify its precise molecular biological mechanism in NSCLC. NLR family CARD domain containing 5 (NLRC5) is widely expressed in tissues and exerts a vital role in anti-tumor immunity. We determined NLRC5 expression by RT-qPCR and western blot assay. The role of NLRC5 in the development of NSCLC was assessed by a loss-of-function assay. CCK-8, Annexin-V-FITC/PI Apoptosis Detection Kit, Transwell, and wound healing assays were used to determine the cell functions. Drug resistance-related proteins were analyzed by western blot assay. Furthermore, the modulation of NLRC5 on carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) expression and subsequent PI3K/AKT signaling was assessed. In this study, a hyper-expression of NLRC5 was found in NSCLC tissues and cell lines. Knockdown of NLRC5 suppressed cell viability, invasion, and migration, and furthermore promoted cell apoptosis in NSCLC cells. Moreover, under normoxia or hypoxia treatment, the upregulation of NLRC5 was related to carboplatin resistance. NLRC5 silencing increased carboplatin-resistant cell chemosensitivity, as evidenced by the increase in the cell inhibition rate and decrease in drug resistance-related protein expression. Mechanistically, NLRC5 knockdown inhibited the expression of CEACAM1 and subsequently blocked the PI3K/AKT signaling pathway. In conclusion, NLRC5 promotes the malignant biological behaviors of NSCLC cells by activating the PI3K/AKT signaling pathway via the regulation of CEACAM1 expression under normoxia and hypoxia.

Mechanism of RNA circHIPK3 Involved in Resistance of Lung Cancer Cells to Gefitinib

To study the mechanism of circular ribonucleic acid (RNA) circHIPK3 involved in the resistance of lung cancer cells to gefitinib, 110 patients with lung cancer were recruited as the research objects, and the tumor tissue and para-cancerous tissue of each patient's surgical specimens were collected and paraffinized to detect the expression of circHIPK3 in different tissues. Gefitinib drug-resistant cell line of lung cancer was constructed with gefitinib to detect cell apoptosis under different conditions. As a result, the relative expression of circHIPK3 in patients with tumor diameter no less than 3 cm was dramatically inferior to that in patients with tumor diameter less than 3 cm (P < 0.05). The relative expression of circHIPK3 in patients with TNM stage II/III was dramatically inferior to that in patients with tumor, node, and metastasis (TNM) stage I (P < 0.05). Expression of circHIPK3 in patients with lymph node metastasis was dramatically inferior to that in patients without lymph node metastasis (P < 0.05). Of the lung cancer tissues of patients with different TNM stages, only six patients had high expression, and the remaining 104 patients had low expression. Moreover, electrophoresis revealed that circHIPK3 can only be amplified in cDNA, but not in gDNA. Gefitinib-mediated apoptosis rate of lung cancer drug-resistant cell lines decreased notably. In summary, the circular RNA circHIPK3 may have a notably low expression in lung cancer tissues, whose low expression had a certain enhancement effect on the drug resistance of lung adenocarcinoma cells to gefitinib.

Circular RNA-UBE2D2 accelerates the proliferation and metastasis of non-small cell lung cancer cells via modulating microRNA-376a-3p/Eukaryotic Translation Initiation Factor 4γ2 axis

Non-small cell lung cancer (NSCLC) ranks first in the morbidity and mortality of malignant tumors in China. As reported, circular RNAs (circRNAs) are emerged in the progress of NSCLC. The study was to figure out the potential mechanism of circ-UBE2D2 in the progression of NSCLC. First, plasmid vectors intervening circ-UBE2D2, microRNA (miR)-376a-3p or Eukaryotic Translation Initiation Factor 4γ2 (EIF4G2) expression were transfected into NSCLC cells, and the expression of circ-UBE2D2, miR-376a-3p and EIF4G2 was detected by reverse transcription quantitative polymerase chain reaction or Western blot. Then, cell proliferation was detected by Cell counting kit-8 assay and plate cloning. Cell apoptosis was tested by flow cytometry. Plate scratches and Transwell were used to detect cell migration and invasion. Finally, the binding sites of circRNA UBE2D2, EIF4G2 and miR-376a-3p were verified by bioinformatics website starBase analysis and dual luciferase reporter gene assay. The results manifested the up-regulation of circ-UBE2D2 expression in NSCLC tissues and cells. Circ-UBE2D2 promoted the proliferation, migration and invasion, but repressed apoptosis of NSCLC cells. Interestingly, circ-UBE2D2 directly targeted miR-376a-3p and up-regulated miR-376a-3p restrained proliferation, migration and invasion, but accelerated apoptosis of NSCLC cells. More importantly, EIF4G2 was the target of miR-376a-3p, and overexpression of EIF4G2 reversed the effects of circ-UBE2D2 downregulation on proliferation, migration, invasion and apoptosis of NSCLC cells. These results suggest that circ-UBE2D2 promotes the proliferation, migration and invasion but restrains apoptosis of lung cancer cells by regulating miR-376a-3p/EIF4G2 axis.

CircCAMSAP1 promotes non-small cell lung cancer proliferation and inhibits cell apoptosis by sponging miR-1182 and regulating BIRC5

Recently, various studies have suggested that circular RNAs (circRNAs) are ubiquitous in various malignant events, including non-small cell lung cancer (NSCLC) and are closely related to cell proliferation and apoptosis. Unfortunately, the molecular functions involved in this action still have little overlap. Therefore, this study aimed to identify a novel circCAMSAP1 role in NSCLC. Overexpression of circCAMSAP1 has been demonstrated in NSCLC lung tissues and cell lines. Sequencing and RNase R experiments were planned to determine whether circCAMSAP1 is looped and exists in NSCLC. We also found that downregulated circCAMSAP1 repressed cell proliferation and increased apoptosis of NSCLC cells in vitro and suppressed xenograft tumor growth in vivo. Furthermore, a luciferase assay revealed that circCAMSAP1 could regulate baculoviral inhibitor of apoptosis protein (IAP) repeat containing 5 (BIRC5, also known as survivin) expression by directly binding to miR-1182. However, BIRC5 without 3ʹ untranslated regions (3ʹUTR) could reverse the influence of downregulated circCAMSAP1 on proliferation and apoptosis in NSCLC. Together, our findings reveal a novel mechanism by which the circCAMSAP1/miR-1182/BIRC5 axis promotes NSCLC progression.

A Concise Review of MicroRNA-383: Exploring the Insights of Its Function in Tumorigenesis

MicroRNAs (miRNAs) are small noncoding RNAs that commonly have 18-22 nucleotides and play important roles in the regulation of gene expression via directly binding to the 3'-UTR of target mRNAs. Approximately 50% of human genes are regulated by miRNAs and they are involved in many human diseases, including various types of cancers. Recently, microRNA-383 (miR-383) has been identified as being aberrantly expressed in multiple cancers, such as malignant melanoma, colorectal cancer, hepatocellular cancer, and glioma. Increasing evidence suggests that miR-383 participates in tumorigenic events including proliferation, apoptosis, invasion, and metastasis as well as drug resistance. Although downstream targets including CCND1, LDHA, VEGF, and IGF are illustrated to be regulated by miR-383, its roles in carcinogenesis are still ambiguous and the underlying mechanisms are still unclear. Herein, we review the latest studies on miR-383 and summarize its functions in human cancers and other diseases. The goal of this review is to provide new strategies for targeted therapy and further investigations.

MicroRNA-383: A tumor suppressor miRNA in human cancer

Downregulated expression of anti-tumor miR-383 has been found in many kinds of cancer. MiR-383 family members can directly target the 3'-untranslated region (3'-UTR) of the mRNA of some pro-tumor genes to attenuate several cancer-related processes, including cell proliferation, invasion, migration, angiogenesis, immunosuppression, epithelial-mesenchymal transition, glycolysis, chemoresistance, and the development of cancer stem cells, whilst promoting apoptosis. Functionally, miR-383 operates as a tumor inhibitor miRNA in many types of cancer, including breast cancer, hepatocellular carcinoma, gastric cancer, pancreatic cancer, colorectal cancer, esophageal cancer, lung cancer, head and neck cancer, glioma, medulloblastoma, melanoma, prostate cancer, cervical cancer, oral squamous cell carcinoma, thyroid cancer, and B-cell lymphoma. Both pro-tumor and anti-tumor effects have been attributed to miR-383 in ovarian cancer. However, only the pro-tumor effects of miR-383 were reported in cholangiocarcinoma. The restoration of miR-383 expression could be considered a possible treatment for cancer. This review discusses the anti-tumor effects of miR-383 in human cancers, emphasizing their downstream target genes and potential treatment approaches.

Circular RNA UBR1 promotes the proliferation, migration, and invasion but represses apoptosis of lung cancer cells via modulating microRNA-545-5p/SSFA2 axis

Lung cancer (LC) is a malignant tumor with the highest incidence in the world, and its specific pathogenesis is still unclear. Circular RNAs (circRNAs) are a group of non-coding RNAs that play a key role in the development and progression of various cancers. The expression pattern and function of circRNAs in LC are still not completely distinct. In this study, it was aimed to study the expression and potential mechanism of circ-UBR1 in LC cells. Then it was found that circ-UBR1 was up-regulated in LC cells, and had microRNA (miR)-545-5p binding sites. Meanwhile, it was confirmed by dual-luciferase reporter assay that circ-UBR1 directly bound to miR-545-5p and then repressed its expression. MiR-545-5p was down-regulated in LC cells and refrained its expression by binding to the downstream target gene SSFA2. Knockdown circ-UBR1 or enhancive miR-545-5p repressed A549 cell proliferation, migration, and invasion, but accelerated apoptosis. After transfection with circ-UBR1 low expression vector, upregulation of SSFA2 apparently reversed the depression of reduced circ-UBR1 on cell proliferation, migration, and invasion, and the promotion of cell apoptosis. Further tumor xenograft experiments in nude mice also confirmed that knockdown of circ-UBR1 could increase the expression of miR-545-5p, but decrease the expression of SSFA2, thus alleviating the progression of LC in vivo. Therefore, these results fully indicate that circ-UBR1 promotes LC cell proliferation, migration, and invasion, but represses apoptosis via the circ-UBR1 axis, which may be a closely related marker and therapeutic target of LC.

Development of a novel embryonic germline gene-related prognostic model of lung adenocarcinoma

Background

Emerging evidence implicates the correlation of embryonic germline genes with the tumor progress and patient's outcome. However, the prognostic value of these genes in lung adenocarcinoma (LUAD) has not been fully studied. Here we systematically evaluated this issue, and constructed a novel signature and a nomogram associated with embryonic germline genes for predicting the outcomes of lung adenocarcinoma.

Methods

The LUAD cohorts retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database were used as training set and testing set, respectively. The embryonic germline genes were downloaded from the website https://venn.lodder.dev. Then, the differentially expressed embryonic germline genes (DEGGs) between the tumor and normal samples were identified by limma package. The functional enrichment and pathway analyses were also performed by clusterProfiler package. The prognostic model was constructed by the least absolute shrinkage and selection operator (LASSO)-Cox regression method. Survival and Receiver Operating Characteristic (ROC) analyses were performed to validate the model using training set and four testing GEO datasets. Finally, a prognostic nomogram based on the signature genes was constructed using multivariate regression method.

Results

Among the identified 269 DEGGs, 249 were up-regulated and 20 were down-regulated. GO and KEGG analyses revealed that these DEGGs were mainly enriched in the process of cell proliferation and DNA damage repair. Then, 103 DEGGs with prognostic value were identified by univariate Cox regression and further filtered by LASSO method. The resulting sixteen DEGGs were included in step multivariate Cox regression and an eleven embryonic germline gene related signature (EGRS) was constructed. The model could robustly stratify the LUAD patients into high-risk and low-risk groups in both training and testing sets, and low-risk patients had much better outcomes. The multi-ROC analysis also showed that the EGRS model had the best predictive efficacy compared with other common clinicopathological factors. The EGRS model also showed robust predictive ability in four independent external datasets, and the area under curve (AUC) was 0.726 (GSE30219), 0.764 (GSE50081), 0.657 (GSE37745) and 0.668 (GSE72094). More importantly, the expression level of some genes in EGRS has a significant correlation with the progression of LUAD clinicopathology, suggesting these genes might play an important role in the progression of LUAD. Finally, based on EGRS genes, we built and calibrated a nomogram for conveniently evaluating patients' outcomes.

Biogenesis, Functions, and Role of CircRNAs in Lung Cancer

CircRNAs, a class of endogenous non-coding RNAs with closed-loop structures, have attracted increasing attention because of their good stability, high specificity of tissue expression, long half-life, and highly conserved sequence. CircRNAs have multiple biological functions, including miRNA sponge, transcription regulator, protein translation, interaction with protein, RNA maturation, and so on. These functions indicate the important role of circRNAs in tumorigenesis and malignant progression and their potential as potent diagnostic biomarkers and therapeutic molecules. In recent years, an increasing body of evidence suggests that circRNAs play a crucial role in proliferation, migration, invasion, and apoptosis of lung cancer cells. Therefore, circRNAs have gradually become a research focus in the diagnosis and treatment of lung cancer patients. This review summarizes the classification, biogenesis, and function of circRNAs, and discusses the role of circRNAs in the diagnosis, prognosis, and treatment of lung cancer patients.

Emerging role of circular RNAs in the pathobiology of lung cancer

Lung cancer is among the leading causes of cancer mortality and incidence in both sexes. Different classes of transcripts have been proposed as molecular markers in this type of cancer. Circular RNAs (circRNAs) are a group of transcripts with circular enclosed and stable configuration. These transcripts are stable in the blood, thus can be used as markers for detection of disorders. Moreover, dysregulation of circRNAs in the affected tissues of patients with different cancers shows their possible roles in the carcinogenesis. Several circRNAs including circPRKC1, circFGFR1, hsa-circ-0020123 and circTP63 have been found to be up-regulated in lung cancer samples. Meanwhile, cir-ITCH, hsa_circ_100395, hsa_circ_0033155, circRNF13, circNOL10, circ-UBR5, circPTK2 and circCRIM1 have been shown to be down-regulated in lung cancer tissues compared with noncancerous counterparts. Finally, prognostic values of circPRKC1, circFGFR1, has-circ-00120123, circTP63, circ_0067934, CDR1as, hsa_circRN_103809 and some other circRNAs have been appraised in lung cancer. In the current manuscript, we describe the impact and utility of circRNAs in the pathology of lung cancer.