Function of Long Noncoding RNA UCA1 on Gastric Cancer Cells and its Clinicopathological Significance in Plasma

Diagnosis and treatment of gastric cancer (GC) at early stages is challenging, causing great difficulties to patients. Long noncoding RNAs (lncRNAs) may serve both as novel molecular markers and therapeutic targets in diagnosis and prognosis of cancers. This study aimed to investigate the function of long non-coding RNA Urothelial Carcinoma Associated 1 (UCA1) on GC cells and evaluate its diagnostic value in GC.

In total, 90 patients with GC and 43 healthy individuals were recruited for the study. Venous blood samples from 40 of the 90 GC patients who underwent surgery were collected before and one week after the surgery. Thirty GC and matched normal tissues were sampled from patients who had undergone surgical resection. The plasma level of UCA1 was quantified using RT-qPCR. In situ hybridization was carried out on formaldehyde-fixed tissue sections from GC patients to detect UCA1. Cell migration assay, cell proliferation assay, and flow cytometry analysis were carried out to study the effect of UCA1 on GC development in vitro.

RT-PCR results showed that the expression levels of UCA1 in GC tissues were significantly higher compared to those in adjacent normal specimens. Down-regulation of UCA1 inhibited the proliferation, migration, and apoptosis of GC cells. In GC patients, plasma expression of UCA1 was significantly up-regulated compared to that in healthy controls (1.417 ± 0.106 vs. 0.223 ± 0.030, p < 0.0001). Plasma UCA1 was significantly correlated with tumor differentiation (p < 0.05), T stage (p < 0.001) and lymph node metastasis (p < 0.001). Plasma UCA1 expression (AUC = 0.883) in post-surgery samples was significantly decreased compared to the expression level of pre-surgery patients (1.403 ± 1.329 versus 0.712 ± 0.944, p < 0.01).

UCA1 promoted proliferation, migration and apoptosis of GC cells and was significantly up-regulated in GC plasma, indicating poor tumor prognosis.