Identification and Comparison of Differentiation-Related Proteins in Hepatocellular Carcinoma Tissues by Proteomics

Development and validation of nomograms for predicting prognosis in patients with solitary HCC: A TRIPOD-Compliant study

Objective

To develop and validate nomograms for predicting the OS and CSS of patients with Solitary Hepatocellular Carcinoma (HCC).

Methods

Using the TRIPOD guidelines, this study identified 5206 patients in the Surveillance, Epidemiology, and End Results (SEER) 17 registry database. All patients were randomly divided in a ratio of 7:3 into a training cohort (n = 3646) and a validation cohort (n = 1560), and the Chinese independent cohort (n = 307) constituted the external validation group. The prognosis-related risk factors were selected using univariate Cox regression analysis, and the independent prognostic factors of OS and CSS were identified using the Lasso-Cox regression model. The nomograms for predicting the OS and CSS of the patients were constructed based on the identified prognostic factors. Their prediction ability was evaluated using the concordance index (C-index), receiver operating characteristic (ROC) curve, and calibration curve in both the training and validation cohorts.

Results

We identified factors that predict OS and CSS and constructed two nomograms based on the data. The ROC analysis, C-index analysis, and calibration analysis indicated that the two nomograms performed well over the 1, 3, and 5-year OS and CSS periods in both the training and validation cohorts. Additionally, these results were confirmed in the external validation group. Decision curve analysis (DCA) demonstrated that the two nomograms were clinically valuable and superior to the TNM stage system.

Conclusion

We established and validated nomograms to predict 1,3, and 5-year OS and CSS in solitary HCC patients, and our results may also be helpful for clinical decision-making.

Silencing of peroxiredoxin 2 suppresses proliferation and Wnt/β-catenin pathway, and induces senescence in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), a common malignancy worldwide, still lacks effective clinical treatment. The study aimed to investigate the oncogenes that affect the progression of HCC and their possible mechanisms. In our study, we initially confirmed a higher level of PRDX2 in the bile of HCC patients compared to those with choledocholithiasis by 2-DE, LC-MS, and ELISA. Subsequently, we demonstrated the high expression of peroxiredoxin 2 (PRDX2) in HCC based on the TCGA database and clinical sample analysis. Furthermore, PRDX2 overexpression enhanced the viability of HCC cells. And PRDX2 silencing induced senescence of HCC cells. In vivo, knockdown of PRDX2 significantly reduced the weight of xenograft tumors. PRDX2 also was found to activate the Wnt/β-catenin pathway by inducing β-catenin nuclear translocation. Consequently, we proved that silencing PRDX2 could inhibit proliferation and Wnt/β-catenin pathway while promoting senescence in HCC cells.

The immunohistochemical detection of peroxiredoxin 1 and 2 in canine spontaneous vascular endothelial tumors

Peroxiredoxin (PRDX) is an antioxidant enzyme family with six isoforms (PRDX1-6). The main function of PRDXs is to decrease cellular oxidative stress by reducing reactive oxygen species, such as hydrogen peroxide, to H2O. Recently, it has been reported that PRDXs are overexpressed in various malignant tumors in humans, and are involved in the development, proliferation, and metastasis of tumors. However, studies on the expression of PRDXs in tumors of animals are limited. Therefore, in the present study, we immunohistochemically investigated the expression of PRDX1 and 2 in spontaneous canine hemangiosarcoma (HSA) and hemangioma (HA), as well as in selected normal tissue and granulation tissue, including newly formed blood vessels. Although there were some exceptions, immunolocalization of PRDX1 and 2 in normal canine tissues was similar to those in humans, rats, or mice. In granulation tissue, angiogenic endothelial cells were strongly positive for PRDX1 and 2, whereas quiescent endothelial cells in mature vessels were negative. Both PRDX1 and 2 were significantly highly expressed in HSA compared to HA. There were no significant differences in the expression of PRDX1 and 2 among the subtypes and primary sites of HSA. These results suggest that PRDX1 and 2 may be involved in the angiogenic phenotypes of endothelial cells in granulation tissue as well as in the behavior in the malignant endothelial tumors.

Identification and functional analysis of senescence-associated secretory phenotype of premature senescent hepatocytes induced by hexavalent chromium

Hexavalent chromium [Cr(VI)] is a common heavy metal pollutant that can cause a number of human disease, including inflammation and cancer. Senescent cells can secrete a variety of molecules known as senescence-associated secretory phenotype (SASP). Our previous studies have confirmed that Cr(VI) can induce premature senescence in L02 hepatocytes, but the composition and the function of the related SASP are still unknown. In order to understand the components of SASP secreted by senescent L02 hepatocytes under the action of Cr(VI), we applied LC-MS/MS-based label-free protein quantification. We found that three SASP components including Coactosin-like protein 1 (COTL1), Alpha-enolase (ENO1), and Peroxiredoxin 2 (PRDX2) were up-regulated, which were confirmed by western blotting and qRT-PCR. Evidence suggested that SASP may promote the development of tumor through chronic inflammatory response, therefore we identified and analyzed the potential biological functions and signaling pathways of these three SASP components using GO and KEGG methods. The interaction between SASP components was analyzed by STRING, and verified by Co-IP. We also found that ENO1 and PRDX2, which have direct interaction, can inhibit the growth and proliferation of wildtype hepatocytes and premature senescent hepatocytes, but can promote the proliferation and behavioral changes of liver tumor cells. The present study provides valuable clues for elucidation of the carcinogenic mechanism of Cr(VI), especially for further prevention and targeted treatment of Cr(VI)-related cancer.

Peroxiredoxin2 downregulation enhances hepatocellular carcinoma proliferation and migration, and is associated with unfavorable prognosis in patients

It has been revealed by our previous proteomic study that the expression profile is different between well-differentiated and poorly differentiated hepatocellular carcinoma (HCC). Among those differently expressed proteins, peroxiredoxin2 (PRDX2) was our protein of interest. The present study aimed to further investigate the value of PRDX2 as a prognostic factor in HCC. Tissue microarrays were used to investigate the expression difference between HCC tissues and their adjacent normal liver tissues. The expression of PRDX2 at both mRNA and protein levels was examined by q-RT-PCR, western blotting and immunohistochemical assessment in HCC tissues and cell line HCCLM3. Silencing of PRDX2 in HCCLM3 was achieved usingpGMLV-SC1 lentiviral vectors. Cell Counting Kit-8 (CCK-8) and Transwell migration assays were used to assess cell proliferation and migration, respectively. Categorical variables were assessed using the Chi-square test, and ordinal variables were examined using the Mann-Whitney U test. The difference of continuous variables between groups were compared with t-tests. The Kaplan-Meier method was used to calculate the overall survival (OS) and disease-free survival (DFS) of patients, and the log-rank test was used to analyze the differences between groups. The results revealed that the expression of PRDX2 was decreased at both the mRNA and protein levels in an HCC cell line compared to that of a normal human liver cell line. PRDX2 protein expression levels were significantly downregulated in HCC tissues and were positively linked to overall survival (OS) and disease-free survival (DFS) of HCC patients. Patients with high PRDX2 expression levels had longer OS and DFS times than those with lower PRDX2 expression. Silencing of PRDX2 in the HCC cell line HCCLM3 promoted cancer cell proliferation and migration. Our findings indicated that PRDX2 may play an important role in HCC development; PRDX2 may serve as a useful prognostic factor and a therapeutic target.