ABSTRACT
Silencing XB130 inhibits cell proliferation and epithelial-mesenchymal transition in non-small cell lung cancer (NSCLC), suggesting that downregulating XB130 expression may impede NSCLC progression. However, the molecular mechanism underlying the regulation of XB130 expression remains unclear. In the present study, the role of the 3'-untranslated region (3'-UTR) in the regulation of XB130 expression was investigated. Recombinant psiCHECK-2 vectors with wild-type, truncated, or mutant XB130 3'-UTR were constructed, and the effects of these insertions on reporter gene expression were examined using a dual-luciferase reporter assay and reverse transcription-quantitative PCR. Additionally, candidate proteins that regulated XB130 expression by binding to critical regions of the XB130 3'-UTR were screened for using an RNA pull-down assay, followed by mass spectrometry and western blotting. The results revealed that insertion of the entire XB130 3'-UTR (1,218 bp) enhanced reporter gene expression. Positive regulatory elements were primarily found in nucleotides 113-989 of the 3'-UTR, while negative regulatory elements were found in the 1-112 and 990-1,218 regions of the 3'-UTR. Deletion analyses identified nucleotides 113-230 and 503-660 of the 3'-UTR as two major fragments that likely promote XB130 expression by increasing mRNA stability and translation rate. Additionally, a U-rich element in the 970-1,053 region of the 3'-UTR was identified as a negative regulatory element that inhibited XB130 expression by suppressing translation. Furthermore, seven candidate proteins that potentially regulated XB130 expression by binding to the 113-230, 503-660, and 970-1,053 regions of the 3'-UTR were identified, shedding light on the regulatory mechanism of XB130 expression. Collectively, these results suggested that complex sequence integrations in the mRNA 3'-UTR variably affected XB130 expression in NSCLC cells.
ABSTRACT
Heterogeneous nuclear ribonucleoprotein A/B (hnRNPAB) is an RNA binding protein that is closely associated with the biological function and metabolism of RNA, which is involved in the malignant transformation of various tumor cells. However, the role and mechanisms of hnRNPAB in non-small cell lung cancer (NSCLC) are still unclear. In the present study, the expression levels of hnRNPAB in NSCLC and normal tissues were analyzed using the human protein atlas database and UALCAN database. The clinical significance of hnRNPAB was assayed using the data of NSCLC cases from The Cancer Genome Atlas database. Subsequently, two stable NSCLC cell lines with hnRNPAB knockdown were constructed and the effects of hnRNPAB silencing on cell viability, migration, invasion and epithelial-mesenchymal transition (EMT) were identified. Genes associated with hnRNPAB expression in NSCLC were screened using the Linked Omics database and verified by quantitative real-time PCR (RT-qPCR). The database analysis indicated that hnRNPAB was mainly expressed in the nucleus of NSCLC cells. Compared with the normal tissues, hnRNPAB expression was overexpressed in NSCLC tissues and was closely associated with the overall survival, sex, tumor-node-metastases classification, and poor prognosis of patients with lung adenocarcinoma. Functionally, knockdown of hnRNPAB inhibited the proliferation, migration, invasion and EMT of NSCLC cells and arrested the cell cycle at G1 phase. Mechanistically, the bioinformatics analysis and RT-qPCR verification demonstrated that hnRNPAB knockdown led to a significant expression change of genes associated with tumorigenesis. In conclusion, the present study indicated that hnRNPAB played an important role in the malignant transformation of NSCLC, supporting the significance of hnRNPAB as a novel potential therapeutic target for the early diagnosis and prognosis of NSCLC.
