RAD51AP1 as an Immune-Related Prognostic Biomarker and Therapeutic Response Predictor in Hepatocellular Carcinoma.

Background: RAD51 associated protein 1 (RAD51AP1) is shown to regulate cell proliferation and cancer progression. However, the immune-infiltrating correlation and the therapeutics guidance of RAD51AP1 in hepatocellular carcinoma (HCC) still need further investigation. Methods: In this study, comprehensive bioinformatic analysis of RAD51AP1 on differential expression, clinicopathologic correlation, prognostic value, and function enrichment were performed in The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO; GSE14520 and GSE76427), and International Cancer Genome Consortium (ICGC) datasets. Besides, the Guangxi cohort containing 50 pairs HCC and adjacent non-cancerous samples from First Affiliated Hospital of Guangxi Medical University was served as validation cohort. Moreover, we explored the predictive value of RAD51AP1 to therapeutics response and its underlying correlation with HCC immunoinfiltration. Results: RAD51AP1 was significantly overexpressed in HCC tissues and had a high diagnostic value of HCC. The shorter survival time and poorer clinical features were showed when RAD51AP1 upregulated, and then a nomogram featuring RAD51AP1 expression and other clinicopathologic factors was established to predict prognosis. In CIBERSORT analysis, higher T cells follicular helper but lower T cells CD4+ memory resting infiltration levels were exhibited when RAD51AP1 upregulated. The ssGSEA analysis demonstrated that high-RAD51AP1 expression subgroup had higher macrophages, Th2 and Treg cells infiltration levels, but lower type II IFN response function. Furthermore, high-RAD51AP1 expression subgroup exhibited the upregulated expression levels of immune-related checkpoint genes, but lower IPS and TIDE scores which suggested a possibly better immunotherapy response. The drug sensitivity analysis showed the high-expression subgroup may be more susceptible to Bexarotene, Doxorubicin, Gemcitabine and Tipifarnib. Conclusion: Taken together, RAD51AP1 is a potential diagnostic and prognostic biomarker. It may be related to the immunosuppressive microenvironment and could be an underlying HCC treatment strategy. However, the conclusions still require further validation studies.

A pan-cancer analysis of the expression and prognostic significance of PDRG1.

Background: PDRG1 are involved in various physiological regulations of cells, include cell proliferation, growth, apoptosis and cell cycle regulation, but their roles in cancer have not been clearly studied. Methods: Firstly, we evaluated the expression and prognostic significance of PDRG1 using a pan-cancer analysis of The Cancer Genome Atlas (TCGA) and Genotypic Tissue Expression (GTEx) databases. Secondly, correlations between PDRG1 and pan-cancer immune cells, m6A methylation, tumor mutation burden (TMB), and microsatellite instability (MSI) were investigated. Finally, we explored the relationship between PDRG1 expression and clinical stage in hepatocellular carcinoma (HCC). Results: We found that PDRG1 was significantly overexpressed in bladder urothelial carcinoma (BLCA), breast invasive carcinoma (BRCA), cholangiocarcinoma (CHOL), liver hepatocellular carcinoma (LIHC), and other tumor tissues and was associated with prognosis. In addition, PDRG1 was closely associated with pan-cancer immune cells, m6A methylation, TMB, and MSI expression. The expression of PDRG1 in HCC was correlated with clinical stage, and western blot assay confirmed that PDRG1 was significantly overexpressed in HCC tissues. Conclusions: PDRG1 may be an important pan-cancer molecular biomarker for diagnosis and prognosis, and our results may provide a theoretical basis for its future clinical application in cancer diagnosis, treatment, and prognosis, and have been preliminarily validated in HCC.

MCM2 promotes the stemness and sorafenib resistance of hepatocellular carcinoma cells via hippo signaling.

OBJECT: A large number of studies have suggested that stemness is an essential mechanism for drug resistance, metastasis and relapse in hepatocellular carcinoma (HCC). The aim of this study was to determine the impact of MCM2 on stemness and identify potential mechanisms that complement the stemness regulatory network in HCC. METHODS: MCM2 expression features and prognostic significance were analyzed in multiple cohorts, including TCGA LIHC dataset, GSE14520 dataset, Guangxi cohort, and GSE76427 dataset. Stemness-related molecules and phenotypes were examined to evaluate the impact of MCM2 on stemness. The expression levels of key molecules of the hippo signaling pathway together with downstream target genes were examined to evaluate the effect of MCM2 on hippo signaling. This was further demonstrated by rescue experiments with hippo signaling pathway inhibitors (super-TDU). Sorafenib-resistant cells were constructed to assess the effect of MCM2 on drug resistance. A xenotransplantation model of nude mice was constructed to validate the role of MCM2 in vivo. RESULTS: MCM2, which is expressed at higher levels in HCC tissue than in normal liver tissues, is a good indicator for distinguishing tumor tissues from normal liver tissues and can help differentiate HCC patients at different BCLC stages. The annotation of the differentially expressed genes in the MCM2 high and low expression groups indicated that MCM2 may be associated with the hippo signaling pathway. In addition, the expression of MCM2 in HCC tissues was correlated with the expression of YAP1/TAZ, which are key molecules of the hippo signaling pathway. It indicated that manipulation of MCM2 expression affects hippo signaling and stemness, while the inhibition of hippo signaling significantly reversed the effect of MCM2 on stemness. Disruption of MCM2 expression significantly elevated the sensitivity of sorafenib-resistant cells to sorafenib, as evidenced by the decrease in IC50 and diminished sphere-forming capacity. The in vivo assays showed that MCM2 effectively enhanced the efficacy of sorafenib. CONCLUSION: MCM2 is a good prognostic marker. MCM2 enhances the stemness of HCC cells by affecting the Hippo signaling pathway, while the downregulation of MCM2 inhibits resistance towards sorafenib.

A novel Peng's test in reducing bile leakage after partial hepatectomy for hepatocellular carcinoma: From an animal study to a clinical cohort Propensity score matching comparative study.

BACKGROUND: Bile leakage (BL) is a common complication of partial hepatectomy for hepatocellular carcinoma (HCC). However, various intraoperative approaches to detect BL have not been widely accepted owing to uncertainty in their treatment effectiveness and complexity of use. MATERIALS AND METHODS: A novel BL-detection approach (Peng's test) was developed in a swine model to determine the pressures generated in the gallbladder and common bile duct (CBD) during the test. A comparative study was then conducted on a prospective cohort of patients using Peng's test versus a retrospective historical cohort patient group using the White Gauze test in partial hepatectomy for HCC. Propensity score matching (PSM) was performed in a 1:1 ratio to balance confounding factors. RESULTS: The maximum pressures with methylene blue injection in the gallbladder and CBD without Pringle's maneuver in the four swines were 103.8 ± 11.8 and 42.3 ± 6.1, respectively. After Pringle's maneuver, 32.0 ± 6.8 mL methylene blue injection led to a maximum pressure in the CBD of 85.3 ± 9.5 cmH2O. The pressures in CBD were 25.8 ± 3.3 and 86.0 ± 9.9 cmH2O when BL appeared at small bile ducts and around the ligation sites, respectively. Of the 206 patients enrolled in the historical control group, 31 (15.0%) developed BL, while of the 54 patients in the study group, only 1 developed grade A BL. The number of BL detected by the routine white gauze test in the control group was significantly lower than that in the study group (Z = -3.002, P = 0.003). After PSM, the incidence of BL in the control group and grade B/C BL was 20.4% and 11.1%, respectively. The corresponding incidences in the study group were 1.9% (χ2 = 7.594, P = 0.006) and 0% (P = 0.027), respectively. The length of hospital stay in the study group was significantly reduced (Z = -6.048, P < 0.001). CONCLUSION: Peng's test for intraoperative BL detection is safe and effective in reducing BL after hepatectomy.

Clinical Significance and Potential Mechanisms of ATP Binding Cassette Subfamily C Genes in Hepatocellular Carcinoma.

The purpose of this investigation was to assess the diagnostic and prognostic significance of ATP binding cassette subfamily C (ABCC) genes in hepatocellular carcinoma (HCC). The Student t-test was used to compare the expression level of ABCCs between HCC and paraneoplastic tissues. Receiver operating characteristic curve (ROC) analysis was applied for diagnostic efficiency assessment. The Kaplan-Meier method and Cox proportional hazards model were respectively applied for survival analysis. Genes with prognostic significance were subsequently used to construct prognostic models. From the perspective of genome-wide enrichment analysis, the mechanisms of prognosis-related ABCC genes were attempted to be elaborated by gene set enrichment analysis (GSEA). It was observed in the TCGA database that ABCC1, ABCC4, ABCC5, and ABCC10 were significantly upregulated in tumor tissues, while ABCC6 and ABCC7 were downregulated in HCC tissues. Receiver operating characteristic analysis revealed that ABCC7 might be a potential diagnostic biomarker in HCC. ABCC1, ABCC4, ABCC5, and ABCC6 were significantly related to the prognosis of HCC in the TCGA database. The prognostic significance of ABCC1, ABCC4, ABCC5, and ABCC6 was also observed in the Guangxi cohort. In the Guangxi cohort, both polymerase chain reaction and IHC (immunohistochemical) assays demonstrated higher expression of ABCC1, ABCC4, and ABCC5 in HCC compared to liver tissues, while the opposite was true for ABCC6. GSEA analysis indicated that ABCC1 was associated with tumor differentiation, nod-like receptor signal pathway, and so forth. It also revealed that ABCC4 might play a role in HCC by regulating epithelial-mesenchymal transition, cytidine analog pathway, met pathway, and so forth. ABCC5 might be associated with the fatty acid metabolism and KRT19 in HCC. ABCC6 might impact the cell cycle in HCC by regulating E2F1 and myc. The relationship between ABCC genes and immune infiltration was explored, and ABCC1,4,5 were found to be positively associated with infiltration of multiple immune cells, while ABCC6 was found to be the opposite. In conclusion, ABCC1, ABCC4, ABCC5, and ABCC6 might be prognostic biomarkers in HCC. The prognostic models constructed with ABCC1, ABCC4, ABCC5, and ABCC6 had satisfactory efficacy.

Clinical implications and molecular mechanisms of Cyclin-dependent kinases 4 for patients with hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) was frequently considered as a kind of malignant tumor with a poor prognosis. Cyclin-dependent kinases (CDK) 4 was considered to be cell-cycle-related CDK gene. In this study, we explored the clinical significance of CDK4 in HCC patients. METHODS: Data of HCC patients were obtained from The Cancer Genome Atlas database (TCGA) and the Gene Expression Omnibus (GEO) database. Kaplan-Meier analysis and Cox regression model were performed to calculate median survival time (MST) and the hazard ration (HR), respectively. The joint-effect analysis and prognostic risk score model were constructed to demonstrate significance of prognosis-related genes. The differential expression of prognostic genes was further validated using reverse transcription-quantitative PCR (RT-qPCR) of 58 pairs of HCC samples. RESULTS: CDK1 and CDK4 were considered prognostic genes in TCGA and GSE14520 cohort. The result of joint-effect model indicated patients in CDK1 and CDK4 low expression groups had a better prognosis in TCGA (adjusted HR = 0.491; adjusted P = 0.003) and GSE14520 cohort (adjusted HR = 0.431; adjusted P = 0.002). Regarding Kaplan-Meier analysis, high expression of CDK1 and CDK4 was related to poor prognosis in both the TCGA (P < 0.001 and = 0.001 for CDK1 and CDK4, respectively) and the GSE14520 cohort (P = 0.006 and = 0.033 for CDK1 and CDK4, respectively). However, only CDK4 (P = 0.042) was validated in RT-qPCR experiment, while CDK1 (P = 0.075) was not. CONCLUSION: HCC patients with high CDK4 expression have poor prognosis, and CDK4 could be a potential candidate diagnostic biomarker for HCC.

High-Mobility Group AT-Hook 1 Served as a Prognosis Biomarker and Associated with Immune Infiltrate in Hepatocellular Carcinoma.

BACKGROUND: The protein high-mobility group AT-hook 1 (HMGA1) has been demonstrated that modulated cellular proliferation, invasion, and apoptosis with a poor prognosis in miscellaneous carcinomas. However, the mechanism of circumstantial carcinogenesis and association with the immune microenvironment of HMGA1 in hepatocellular carcinoma (HCC) had not been extensively explored. METHODS: The gene expression, clinicopathological correlation, and prognosis analysis were performed in the data obtained from TCGA. The results were further validated by ICGC and GEO database and external validation cohort from Guangxi. The HMGA1 protein expression was further examined in the HPA database. Biological function analyses were conducted by GSEA, STRING database, and Coexpedia online tool. Using TIMER and CIBERSORT method, the relationship between immune infiltrate and HMGA1 was investigated. RESULTS: In HCC, HMGA1 had much higher transcriptional and proteomic expression than in corresponding paraneoplastic tissue. Patients with high HMGA1 expression had a poor prognosis and unpromising clinicopathological features. High HMGA1 expression was closely related to the cell cycle, tumorigenesis, substance metabolism, and immune processes by regulating complex signaling pathways. Notably, HMGA1 may be associated with TP53 mutational carcinogenesis. Moreover, increased HMGA1 expression may lead to an increase in immune infiltration and a decrease in tumor purity in HCC. CIBERSORT analysis elucidated that the amount of B cell naive, B cell memory, T cells gamma delta, macrophages M2, and mast cell resting decreased when HMGA1 expression was high, whereas T cells follicular helper, macrophages M0, and Dendritic cells resting increased. CONCLUSION: In conclusions, HMGA1 is a potent prognostic biomarker and a sign of immune infiltration in HCC, which may be a potential immunotherapy target for HCC.

CYP2C8 Suppress Proliferation, Migration, Invasion and Sorafenib Resistance of Hepatocellular Carcinoma via PI3K/Akt/p27kip1 Axis.

BACKGROUND: Cytochrome P450 2C8 (CYP2C8) gene is one of the members of the cytochrome P450 enzymes (CYPs) gene family. The aim of this study was to reveal the function of CYP2C8 in hepatocellular carcinoma (HCC) and its effect on the sorafenib resistance. METHODS: Differential expression analysis in multiple HCC datasets all suggested that CYP2C8 expression was significantly decreased in HCC tissues, compared with para-carcinoma liver tissues. The expression level of CYP2C8 was subsequently compared between HCC tissues and para-carcinoma liver tissues of 70 patients form Guangxi, China, with the result consistent with the above. Survival analysis and ROC analysis indicated that CYP2C8 was equipped with satisfactory diagnostic and prognostic value in HCC. To examine the effect of CYP2C8 on the malignant phenotype of HCC cells, stable transcriptional cell lines with CYP2C8 over-expression were established, and then Cell Counting Kit-8 (CCK8) assay, colony formation assay, cell cycle assay, cell invasion assay and wound healing assay were performed. RESULTS: The results of aforementioned assays suggested that CYP2C8 over-expression restricted the proliferation, clonality, migration, invasion and cell cycle of HCC cells but had no significant effect on cell apoptosis. The enrichment analysis in terms of sequencing data of HCC cell lines with stable CYP2C8 over-expression suggested that CYP2C8 might be related to PI3K/Akt/p27Kip1 axis. The inhibition of CYP2C8 over-expression on PI3K/Akt/p27Kip1 axis was subsequently demonstrated with Western blot assay. In the rescue experiment, it was observed that both P27 inhibitor and PI3K agonist counteracted the repressed malignant phenotype caused by CYP2C8 over-expression, which further demonstrated that CYP2C8 played a role in HCC cells via PI3K/Akt/p27Kip1 axis. DISCUSSION: The results demonstrated that CYP2C8 enhances the anticancer activity of sorafenib in vitro assays and in tumor xenograft model, with Ki-67 down-regulation and PI3K/Akt/p27Kip1 axis inhibition. In conclusion, these findings hinted that CYP2C8 restricted malignant phenotype and sorafenib resistance in HCC via PI3K/Akt/p27kip1 axis.