Expression and mechanism of long non-coding RNA GHRLOS2 in colorectal cancer

Objective To investigate the expression and mechanism of long non-coding RNA (lncRNA) GHRLOS2 in colorectal cancer tissues and cells.

Methods Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression levels of GHRLOS2 and microRNA-33b-5p (miR-33b-5p) in colorectal cancer tissues or cells. Overexpressing of GHRLOS2 in HCT116 and SW480 colorectal cancer cell lines were constructed, and the effects of overexpression of GHRLOS2 on the migration and invasion abilities in HCT116 and SW480 cell lines were detected by wound healing assay and Transwell assay. Glucose content in cells of overexpressing GHRLOS2 and control cells was detected using a glucose detection kit. Western blot was used to detect the expression level of PCK1 protein in cells. The targeted binding relationship between miR-33b-5p and PCK1 was predicted based on bioinformatics methods.

Results The qRT-PCR results showed that the expression level of GHRLOS2 in colorectal cancer tissue samples was lower than that in adjacent non-cancerous tissues, and was lower in colorectal cancer cells than that in normal colon epithelial cells (P < 0.05). The expression of GHRLOS2 was correlated with grade classification, staging, and lymph node metastasis (P < 0.05). The expression level of miR-33b-5p in colorectal cancer tissues was higher than that in corresponding adjacent non-cancerous tissues (P < 0.001). The results of wound healing assay, Transwell assay, and glucose content detection showed that overexpression of GHRLOS2 significantly inhibited the invasion, migration, and glucose metabolism of colorectal cancer cells. Overexpression of GHRLOS2 inhibited the expression level of miR-33b-5p; GHRLOS2 functioned as a molecular sponge for miR-33b-5p, and PCK1 was a target of miR-33b-5p; overexpression of GHRLOS2 competitively bound to miR-33b-5p, thereby promoting increased expression of PCK1.

Conclusion The expression of GHRLOS2 is downregulated in colorectal cancer tissues and cells, and it may regulate the invasion, migration, and glucose metabolism of colorectal cancer cells through the miR-33b-5p/PCK1 pathway, making it a potential biological target for targeted therapy of colorectal cancer.