Down‐regulation of microRNA‐19b in hormone receptor‐positive/HER2‐negative breast cancer

Abstract

miR-19b (miR-19b-3p) has been reported to be correlated with either favorable or unfavorable events in several cancers. However, no study has been conducted to evaluate the expression level of miR-19b in patients with breast cancer (BC). This study was aimed to investigate the expression level of miR-19b in human malignant and healthy breast tissues with histopathology of ER+/PR+/HER2-. We performed a miRNA real-time PCR to detect differential expression of miR-19b in 40 BC, including 17 BC with familial background and 23 BC without familial background, and 12 non-tumoral tissues. Moreover, a bioinformatics prediction upon miR-19b functionality in BC cells was performed. The miR-19b expression level was significantly down-regulated in BC, BC with familial background, and BC without familial background compared with its expression in normal tissue (p value, <0.0001; fold change, -7.45; p value, 0.0003; fold change, -6.45; and p value, 0.0005; fold change, -8.41, respectively). Moreover, according to the AUCs (area under curve) of receiver operating characteristic (ROC) curves, miR-19b can significantly distinguish all defined categories. Last, in agreement with our experimental findings, proteoglycans in cancer, pathways in cancer, FoxO signaling pathway, central carbon metabolism in cancer, p53 signaling pathway, transcriptional misregulation in cancer, and prolactin signaling pathway were predicted as miR-19b-related signaling pathways. In summary, down-regulation of miR-19b in BC vs healthy tissue suggests that mir-19b can function as a tumor suppressor. Our results shed additional information on controversial expression pattern of miR-19b depending on different cancer types.

<p>Circular RNA SMARCA5 inhibits the proliferation, migration, and invasion of non-small cell lung cancer by miR-19b-3p/HOXA9 axis</p>

“…Besides, miR-19b-3p is an independent prognostic factor associated with OS and disease-free survival in colon cancer patients 16. The miR-19b expression level is significantly down-regulated in breast cancer and may function as a tumor suppressor 17. In addition, plasma miR-19b-3p level is significantly higher in the lung cancer patients, compared with the healthy control group 18.…”

HNRNPA2/B1 is upregulated in endocrine-resistant LCC9 breast cancer cells and alters the miRNA transcriptome when overexpressed in MCF-7 cells

“…Both miR193a-5p and miR-193a-3p repressed MCF-7 and MDA-MB-231 cell proliferation by different targets. miR-193a-3p suppressed cell growth by inhibiting CCND1, PLAU , and SEPN1 and inhibited cell motility by suppressing PLAU expressionTumor suppressor in many cancers.miR-19a-3p−0.70Lower in MCF-7 than MDA-MB-231 cells 211 .oncomiR in breast cancer cells 212 miR-19b-3p−0.82Expression level was significantly down‐regulated in BCa vs normal breast 213 . Downregulated in SK-BR-3 cells resistant to the PI3K inhibitor saracatinib and miR-19b-3p directly targets PIK3CA 214 Tumor suppressormiR-20a-5p−0.64Higher in TNBC than luminal A invasive breast ductal cancer 198 .…”

The miR‐19b‐3p‐MAP2K3‐STAT3 feedback loop regulates cell proliferation and invasion in esophageal squamous cell carcinoma

“…However, the role of miR-19b-3p is not without controversy. The miR-19b expression level is significantly downregulated and function as a tumor suppressor in breast cancer [29]. However, the expression and function of miR-19b-3p in ESCC development remains unclear.…”