OBJECTIVE: To conduct a pan-cancer analysis of the expression of long non-coding RNA (lncRNA) MIR22HG and explore its association with clinical characteristics. METHODS: We analyzed the expression of MIR22HG in different tumors and its association with clinical staging, lymph node metastasis, tumor mutation burden (TMB) and microsatellite instability (MSI) using R package based on the Cancer Genome Atlas (TCGA) datasets. The relationship between MIR22HG expression and infiltrating immune cells was analyzed using TIMER algorithm. The association of MIR22HG gene alteration frequency with the clinical outcomes was examined using cBioPortal online software. Data form Genomics of Drug Sensitivity in Cancer (GDSC) were used to analyze the relationship between MIR22HG and the sensitivity of chemotherapy drugs. We specifically analyzed MIR22HG expression in hepatocellular carcinoma (HCC) and its correlation with sorafenib treatment using GEO database and verified the results in 12 pairs of HCC specimens. Kaplan-Meier analysis was performed to analyze the correlation of MIR22HG with the outcomes of sorafenib treatment. We also tested the effects of MIR22HG overexpression and knockdown on IC₅₀ of sorafenib in HCC cells. RESULTS: MIR22HG was downregulated in most tumors (P < 0.05), where its deletion mutations were frequent, and associated with a poor prognosis (P < 0.05). In many tumors, MIR22HG expression level was correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, immune checkpoint-related genes, and sensitivity to common chemotherapeutic drugs (P < 0.05). Among the 6 common infiltrating immune cells in cancers, neutrophil infiltration had the strongest correlation with MIR22HG expression level, especially in breast cancer, rectal cancer and kidney renal papillary cell carcinoma (P < 0.05). MIR22HG was downregulated in HCC in association with HCC progression (P < 0.05). In HCC patients, a low MIR22HG expression was associated with a favorable outcome after sorafenib treatment (HR=2.94, P=0.075) and was capable of predicting the response to sorafenib treatment (AUC=0.8095). Compared with the negative control, MIR22HG overexpression obviously reduced sorafenib sensitivity (with IC₅₀ of 7.731 vs 15.61) while MIR22HG knockdown increased sorafenib sensitivity of HCC cells (with IC₅₀ of 7.986 vs 5.085). CONCLUSION MIR22HG expression level is correlated with clinical stage, lymph node metastasis, TMB, MSI, immune cell infiltration, and chemosensitivity in most cancer, suggesting its potential as an immunotherapeutic target and also a prognostic biomarker for tumors.
Biomarkers, Tumor/genetics* ; Carcinoma, Hepatocellular/pathology* ; Gene Expression Regulation, Neoplastic ; Humans ; Liver Neoplasms/pathology* ; Lymphatic Metastasis ; Microsatellite Instability ; RNA, Long Noncoding/genetics* ; Sorafenib/pharmacology*

Objective: To investigate the effect and possible mechanism of Y-box-binding protein 1 (YB-1) on sorafenib resistance in hepatoma cells. Methods: Lentiviral vectors with YB-1 overexpression and knockdown were constructed, respectively, to stimulate human hepatoma cell lines (HepG2 and Huh7) alone or in combination with sorafenib.The overexpression part of the experiment was divided into four groups: overexpression control group (Lv-NC), YB-1 overexpression group (Lv-YB-1), overexpression control combined with sorafenib resistance group (Lv-NC+sorafenib), YB-1 overexpression combined with sorafenib resistance group (Lv-YB-1 + sorafenib). The knockdown part of the experiment was also divided into four groups: knockdown control group (Lv-shNC), YB-1 knockdown group (Lv-shYB-1), knockdown control combined with sorafenib resistance group (Lv-shNC + sorafenib), YB-1 knockdown combined with sorafenib resistance group (Lv-shYB-1 + sorafenib). The occurrence of cell apoptosis was detected by TUNEL. The protein expression levels of phosphorylated (p)-ERK and ERK, key proteins in the extracellular regulatory protein kinase (ERK) signaling pathway, were detected by Western blot and quantified by ImageJ software. Subcutaneous tumorigenesis experiments were performed in nude mice. The effect of YB-1 on the efficacy of sorafenib was verified in vivo. The comparison between the two sets of data was carried out by an independent sample t-test. One-way ANOVA was used for comparisons between the three groups of data above. Results: Sorafenib had accelerated the occurrence of apoptosis in hepatoma cells, while YB-1 overexpression had inhibited cell apoptosis, and at the same time also inhibited the apoptosis-accelerating impact of sorafenib. On the contrary, YB-1 knockdown accelerated cell apoptosis and amplified the induction effect of sorafenib on apoptosis. Furthermore, sorafenib resistance had down-regulated p-ERK levels (HepG2: Lv-NC 0.685 ± 0.143, Lv-NC + sorafenib 0.315 ± 0.168, P < 0.05; Huh7: Lv-NC 0.576 ± 0.078, Lv-NC + sorafenib 0.150 ± 0.131, P < 0.01), whereas YB-1 overexpression had inhibited sorafenib resistance p-ERK reduction (HepG2: Lv-NC + sorafenib 0.315 ± 0.168, Lv-YB-1 + sorafenib 0.688 ± 0.042, P < 0.05; Huh7: Lv-NC + sorafenib 0.150 ± 0.131, Lv-YB-1 + sorafenib 0.553 ± 0.041, P < 0.05). YB-1 knockdown further increased sorafenib-induced p-ERK downregulation (HepG2: Lv-shNC + sorafenib 0.911 ± 0.252, Lv-shYB-1 + sorafenib 0.500 ± 0.201, P < 0.05; Huh7: Lv-shNC + sorafenib 0.577 ± 0.082, Lv-shYB-1 + sorafenib 0.350 ± 0.143, P < 0.05), which was further verified in naked mice (Lv-shNC + sorafenib 0.812 ± 0.279, Lv-shYB-1 + sorafenib 0.352 ± 0.109, P < 0.05). Conclusion: YB-1 mediates the occurrence of sorafenib resistance via the ERK signaling pathway in hepatoma cells.
Humans ; Cell Line, Tumor ; Sorafenib/pharmacology* ; Drug Resistance, Neoplasm ; Y-Box-Binding Protein 1/metabolism* ; Carcinoma, Hepatocellular/metabolism* ; MAP Kinase Signaling System ; Animals ; Mice ; Mice, Nude