Reduced expression of circRNA hsa_circ_001888 in gastric cancer and its clinical significance

Non-Coding RNA as Biomarkers and Their Role in the Pathogenesis of Gastric Cancer-A Narrative Review

Non-coding RNAs (ncRNAs) represent a broad family of molecules that regulate gene expression, including microRNAs, long non-coding RNAs and circular RNAs, amongst others. Dysregulated expression of ncRNAs alters gene expression, which is implicated in the pathogenesis of several malignancies and inflammatory diseases. Gastric cancer is the fifth most frequently diagnosed cancer and the fourth most common cause of cancer-related death. Studies have found that altered expression of ncRNAs may contribute to tumourigenesis through regulating proliferation, apoptosis, drug resistance and metastasis. This review describes the potential use of ncRNAs as diagnostic and prognostic biomarkers. Moreover, we discuss the involvement of ncRNAs in the pathogenesis of gastric cancer, including their interactions with the members of major signalling pathways.

miRNAs as short non-coding RNAs in regulating doxorubicin resistance

The treatment of cancer patients has been prohibited by chemoresistance. Doxorubicin (DOX) is an anti-tumor compound disrupting proliferation and triggering cell cycle arrest via inhibiting activity of topoisomerase I and II. miRNAs are endogenous RNAs localized in cytoplasm to reduce gene level. Abnormal expression of miRNAs changes DOX cytotoxicity. Overexpression of tumor-promoting miRNAs induces DOX resistance, while tumor-suppressor miRNAs inhibit DOX resistance. The miRNA-mediated regulation of cell death and hallmarks of cancer can affect response to DOX chemotherapy in tumor cells. The transporters such as P-glycoprotein are regulated by miRNAs in DOX chemotherapy. Upstream mediators including lncRNAs and circRNAs target miRNAs in affecting capacity of DOX. The response to DOX chemotherapy can be facilitated after administration of agents that are mostly phytochemicals including curcumol, honokiol and ursolic acid. These agents can regulate miRNA expression increasing DOX's cytotoxicity. Since delivery of DOX alone or in combination with other drugs and genes can cause synergistic impact, the nanoparticles have been introduced for drug sensitivity. The non-coding RNAs determine the response of tumor cells to doxorubicin chemotherapy. microRNAs play a key role in this case and they can be sponged by lncRNAs and circRNAs, showing interaction among non-coding RNAs in the regulation of doxorubicin sensitivity.

Detecting plasma hsa_circ_0061276 in patients with gastric cancer by reverse transcription-digital polymerase chain reaction

Background

The role of circular RNAs (circRNAs) in the occurrence of gastric cancer is still unclear. Therefore, the diagnostic value and mechanisms underlying hsa_circ_0061276 in the occurrence of gastric cancer were explored.

Methods

Reverse transcription-droplet digital polymerase chain reaction was used to detect the copy number of hsa_circ_0061276 in plasma from healthy individuals, as well as from patients with gastric precancerous lesions or early-stage or advanced gastric cancer. Plasmids overexpressing or knocking down hsa_circ_0061276 expression were transfected into gastric cancer cells. The effects on the growth, migration, and cell cycle distribution of gastric cancer cells were then analyzed. Finally, miRanda and RNAhybrid were used to explore the binding sites between hsa_circ_0061276 and microRNAs (miRNAs). A double luciferase reporter gene assay was used to confirm the miRNA sponge effect.

Results

The results show that plasma hsa_circ_0061276 copy number showed a trend of a gradual decrease when comparing healthy controls to the early cancer group and advanced gastric cancer group. Overexpression of hsa_circ_0061276 inhibited the growth and migration of gastric cancer cells. Through bioinformatic analyses combined with cellular experiments, it was found that hsa_circ_0061276 inhibited the growth of gastric cancer by binding to hsa-miR-7705.

Conclusion

Hsa_circ_0061276 may be a new biomarker for gastric cancer. The tumor suppressor role of hsa_circ_0061276 on gastric cancer likely occurs through a sponge effect on miRNAs such as hsa-miR-7705.

The diagnostic significance of blood-derived circRNAs in NSCLC: Systematic review and meta-analysis

Background

Using blood-derived circular RNAs (circRNAs) may be an efficient tool for noninvasive fluid biopsy in diagnosing non-small cell lung cancer (NSCLC). However, no relevant systemic meta-analysis has been conducted so far to support the diagnostic value of using blood-derived circRNAs in NSCLC clinically. The aim of this study is to clarify the issue through a meta-analysis.

Methods

A systematic search strategy was used to search relevant literature in the databases of PubMed, Web of Science, and Cochrane Library from 2017 to 2022. The relationship between the diagnostic accuracy of circRNAs and NSCLC was analyzed. For the purpose of evaluating the quality of the literature, Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) was used. Statistical analyses were assessed using Stata software (version 17.0) and META-DISC (version 1.4).

Results

The meta-analysis included 1,093 patients with NSCLC and 959 controls. Results are as follows: pooled sensitivity, 0.78 (95% CI = 0.71–0.83, I² = 71.86); pooled specificity, 0.76 (95% CI = 0.70–0.82, I² = 70.12); pooled positive likelihood ratio (PLR), 3.3 (95% CI = 2.6–4.2, I² = 37.56); pooled negative likelihood ratio (NLR), 0.29 (95% CI = 0.23–0.37, I² = 64.67); diagnostic odds ratio (DOR), 11.42 (95% CI = 7.88–16.56, I² = 99.05); area under the receiver operating characteristic curve (AUC), 0.84 (95% CI = 0.80–0.87). Based on the subgroup analysis, it appears that the heterogeneity is primarily caused by the NSCLC subgroup.

Conclusion

circRNAs are highly useful diagnostic biomarkers for NSCLC in China. Further prospective studies on the diagnostic value of circRNAs should be conducted in multiple countries.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022323804.

Circ_0010235 Regulates HOXA10 Expression to Promote Malignant Phenotypes and Radioresistance in Non-small Cell Lung Cancer Cells Via Decoying miR-588

Background:

Circular RNAs (circRNAs) are key modulators in carcinogenesis and radioresistance in multiple kinds of human cancers.

Aims:

To explore the role of circ_0010235 in non-small cell lung cancer (NSCLC).

Study Design:

Cell culture study and animal study.

Methods:

The detection of circ_0010235, microRNA-588 (miR-588), and homeobox protein A10 (HOXA10) was implemented via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). CCK-8, EdU, flow cytometry, transwell, and wound healing assays. These strategies were applied to evaluate cell functions. The western blot technique was employed for protein examination. The colony formation assay was used to determine cell survival after radiation treatment. In vivo research was performed by tumor xenograft assay. The binding analysis was also carried out through dual-luciferase reporter and RNA immunoprecipitation studies.

Results:

Circ_0010235 had an enhanced expression in NSCLC. Circ_0010235 deficiency inhibited cell proliferation, invasiveness, and migratory ability but promoted apoptosis and radiosensitivity. Downregulation of circ_0010235 decelerated tumor growth and promoted radiation sensitivity in vivo. Circ_0010235 was controlled biologically in NSCLC cells by combining with miR-588 and targeting miR-588. HOXA10 acted as a target of miR-588. MiR-588 upregulation inhibited NSCLC cell malignant phenotypes and elevated radiosensitivity via downregulating HOXA10. Circ_0010235 could regulate the level of HOXA10 by sponging miR-588.

Conclusion:

Circ_0010235 contributed to the malignant progression of NSCLC, but suppressed the radiation sensitivity via targeting miR-588 to induce HOXA10 upregulation.

Reduced expression of circRNA hsa_circ_001888 in gastric cancer and its clinical significance

Background

Circular RNAs (circRNAs) are a novel family of endogenous RNAs. Recent studies have demonstrated that circRNAs are potential novel biomarkers for diagnosing cancers. However, little is known about the role of circRNAs in gastric cancer (GC). This study aimed to identify the relationship between GC and a new circRNA named hsa_circ_001888.

Methods

Hsa_circ_001888 expression levels were measured by quantitative reverse transcription‐polymerase chain reaction (qRT‐PCR) in GC cell lines, tissues, and plasma samples. Then, the associations between the expression level of hsa_circ_001888 and the clinicopathological features of patients with GC were further investigated. A receiver operating characteristic (ROC) curve was generated to evaluate the diagnostic value of hsa_circ_001888.

Results

In this study, hsa_circ_001888 was first found to be significantly downregulated in GC cell lines (AGS and MKN‐45), tissues, and plasma samples compared to control samples. Clinicopathological features showed that the expression of hsa_circ_001888 in GC tissues was associated with differentiation and in GC plasma linked with serum CEA and CA19‐9 levels. The areas under the ROC curves of hsa_circ_001888 in tissues and plasma were 0.654 and 0.66, respectively.

Conclusions

Hsa_circ_001888 may serve as a potential biomarker in the diagnosis of GC and may be involved in GC development.