Plasma exo-hsa_circRNA_0056616: A potential biomarker for lymph node metastasis in lung adenocarcinoma

Abstract

Background: To investigate the relationship between CXCR4-related circular RNAs (circRNAs) in exosomes and lymph node metastasis of lung adenocarcinoma. Methods: Totally 41 lung adenocarcinoma tissues (21 with lymph node metastasis and 20 without) were collected. Expression of CXCR4 protein was detected by western blotting analysis. A stable PC9/CXCR4-shRNA and PC14/CXCR4-shRNA knockdown lung adenocarcinoma cell lines were established and subjected to functional assays (cell proliferation, colony formation, migration and invasion) for phenotype changes. Exo-hsa-circRNAs (has-circRNAs in exosomes) were detected in vivo and in vitro. The diagnostic value of differentially expressed exo-has-circRNAs was evaluated. Results: Expression levels of CXCR4 were higher in patients with lymph node metastasis than in those without (P = 0.001). Silencing CXCR4 expression in PC9 and PC14 cell lines with short hairpin RNA could effectively abolish colony formation frequency, proliferation rate, migration rate, and the number of invasive cells (all P < 0.001). Exo_circRNA_0056616 was detected in both PC-9/CXCR4-shRNA cells and lung adenocarcinoma plasma at significantly higher levels than in the corresponding control (P < 0.001). When a receiver operating characteristic (ROC) curve for plasma exo-hsa_circRNA_0056616 levels and diagnosis of lymph node metastasis of lung adenocarcinoma was generated, a cutoff value of 0.394 was identified with an area under the curve of 0.812 (95% confidence interval 0.720-0.903), a sensitivity of 0.792, and specificity of 0.810. Conclusions: Taken together, our findings suggested that CXCR4 was higher in the lung adenocarcinoma tissues with lymph node metastasis. Higher plasma levels of exo-hsa_circRNA_0056616 in these patients also suggest that this circRNA represents a potential biomarker for lymph node metastasis predictor in lung adenocarcinoma.

The crosstalk between circular RNAs and the tumor microenvironment in cancer metastasis

“…Thus, it can be reckoned that local tumor cell homing may be mediated by exosomes, which can facilitate the crosstalk with other cells within the TME. LUAD patients with lymph node metastasis had higher plasma levels of exo-hsa_circRNA_0056616 and CXCR4 expression than those without [113]. CircRNAs can build up a ceRNA network with miRNAs.…”

“…CD44 is another tumor cell receptor for ECM proteins, more specifically, a highly polymorphic receptor for hyaluronan (HA), part of the immunoglobulin Table 1 The crosstalk between circRNAs and the TME in cancer metastasis ↑ upregulation; ↓ downregulation; ECM: extracellular matrix; CRC: colorectal cancer; BC: bladder cancer; HCC: hepatocellular carcinoma; CC: colon cancer; OSCC: oral squamous cell carcinoma; PDAC: pancreatic ductal adenocarcinoma; TIMPs: tissue inhibitors of metalloproteinases; ITGB8: integrin β8; GC: gastric cancer; COL1A1: collagen type I α 1; FN1: fibronectin 1; LUAD: lung adenocarcinoma; CAFs: cancer-associated fibroblasts; CCRCC: clear cell renal cell carcinoma; AR: androgen receptor; PAAD: pancreatic adenocarcinoma; NSCLC: non-small cell lung cancer; TERT: telomerase reverse transcriptase; ISM: Isthmin; VM: vasculogenic mimicry; SOX9: SRY (sex determining region Y)-box 9; TPT1: translationally controlled tumor protein; NFPAs: non-functioning pituitary adenomas; EOC: epithelial ovarian cancer; MTDH: metadherin Bladder cancer urine↑ hsa_circ_0137439/miR-142-5p/MTDH [110] hsa_circRNA_0056616 LUAD↑ Unknown [113] receptor superfamily, and a surface proteoglycan. CD44 proteins comprise a major class of single-pass transmembrane glycoproteins and connect the extracellular matrix to the cytoskeleton to induce downstream signaling for the promotion of tumor invasion [56].…”

Circular RNAs: Emerging Role in Cancer Diagnostics and Therapeutics

“…CircRNA_0056616 was upregulated in tissues and plasma of LUAD patients and it was correlated with TNM stage and lymph node metastasis (He F. et al, 2020). Circ_0000190 and circ_000164 were overexpressed in plasma and tissues from LC patients and expression of circ_0000190 was associated with latestage, extra-thoracic metastasis, poor survival, and prognosis (Luo Y. H. et al, 2020).…”

Emerging Roles of Exosomal Circular RNAs in Cancer

“…In lung adenocarcinoma, hsa_circRNA_0056616 was downregulated in plasma exosome. When a receiver operating characteristic curve for exosomal hsa_circRNA_0056616 levels in the context of diagnosis of lymph node metastasis was generated ( n = 90), the AUC value was 0.812, suggesting that hsa_circRNA_0056616 could be a potential biomarker for lymph node metastasis ( He et al, 2020 ). In small cell lung cancer, serum exosomal FECR1 was associated with poor survival and clinical response to chemotherapy ( Li et al, 2019 ).…”