Silencing of the chemokine CXC receptor 4 (CXCR4) hampers cancer progression and increases cisplatin (DDP)-sensitivity in clear cell renal cell carcinoma (ccRCC)

Systematic analysis of RNASET2 gene as a potential prognostic and immunological biomarker in clear cell renal cell carcinoma

BACKGROUND

RNASET2 has been identified as an oncogene with anti-angiogenic and immunomodulatory effects in a variety of cancers, but its function in clear cell renal cell carcinoma (ccRCC) is still not well understood.

METHODS

The RNASET2 expression matrix was extracted from the The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets and analyzed for diagnostic and prognostic value. RNASET2 mRNA expression was detected by quantitative polymerase chain reaction (qPCR) in ccRCC patients and renal cancer cell lines. Wound healing assay, transwell assay, western blotting, and tube formation assays were used to evaluate the function of RNASET2 in renal cancer in vitro. In addition, transcriptome sequencing was performed on knockdown RNASET2 kidney cancer cells to analyze their potential signaling pathways. Moreover, the immune microenvironment and mutational status were evaluated to predict the potential mechanisms of RNASET2 involvement in renal cancer progression. Sensitivity to common chemotherapeutic and targeted agents was assessed according to the Genomics of Drug Sensitivity in Cancer (GDSC) database.

RESULTS

RNASET2 expression was significantly upregulated in ccRCC tissues and renal cancer cell lines, predicting poor prognosis for patients. In vitro experiments showed that silencing RNASET2 inhibited the migration and pro-angiogenic ability of renal cancer cells. Transcriptome sequencing suggested its possible involvement in the remodeling of the immune microenvironment in renal cell carcinoma. Furthermore, bioinformatics analysis and immunohistochemical staining showed that RNASET2 was positively correlated with the infiltration abundance of regulatory T cells. Finally, we mapped the mutational landscape of RNASET2 in ccRCC and found its predictive value for drug sensitivity.

CONCLUSIONS

Our results suggest that RNASET2 is a promising biomarker and therapeutic target in ccRCC.

CGN Correlates With the Prognosis and Tumor Immune Microenvironment in Clear Cell Renal Cell Carcinoma

This study aimed to screen and verify the important prognostic genes related to clear cell renal cell carcinoma (ccRCC) and further analyze their relationship with the immune microenvironment. Gene expression profiles from the TCGA-KIRC, GSE46699, GSE36895, and GSE16449 datasets were utilized to explore differentially co-expressed genes in ccRCC. We screened 124 differentially co-expressed genes using a weighted gene co-expression network and differential gene expression analyses. Univariate and multivariate Cox survival analyses revealed that the expressions of genes CGN, FECH, UCHL1, and WT1 were independently related to the overall survival of ccRCC patients. Kaplan–Meier survival analysis was performed, and CGN was found to have the strongest correlation with the prognosis of ccRCC patients and was consequently selected for further analyses and experimental verification. The results showed that NK cell activation, resting dendritic cells, resting monocytes, and resting mast cells were positively correlated with CGN expression; CD4+ memory activated T cells, regulatory T cells, and M0 macrophages were negatively correlated with CGN expression. Finally, using western blotting and reverse transcription polymerase chain reaction, we verified that the CGN protein level was down-regulated in ccRCC samples, which was consistent with the mRNA levels. CGN was thus identified as diagnosis and prognosis biomarker for ccRCC and is related to the immune microenvironment.

Silencing of specificity protein 1 protects H9c2 cells against lipopolysaccharide-induced injury via binding to the promoter of chemokine CXC receptor 4 and suppressing NF-κB signaling

G protein-coupled protein receptor CXC chemokine receptor 4 (CXCR4) has been shown to be involved in the development of sepsis; however, it remains unclear whether CXCR4 participates in the septic myocardial injury. In our study, treatment with lipopolysaccharide (LPS) increased the expression of specificity protein 1 (SP1) and CXCR4 in H9c2 cells. Notably, a positive association between SP1 and CXCR4 expression was observed in LPS-treated H9c2 cells, and SP1 positively regulated CXCR4 expression in H9c2 cells. Moreover, silencing of SP1 or CXCR4 suppressed LPS-induced inflammation and cell apoptosis in H9c2 cells, as evidenced by the increase in cell viability and decrease in lactate dehydrogenase release, interleukin (IL)-6, IL-8, and tumor necrosis factor (TNF)-α levels, and caspase-3 activity. Additionally, overexpression of CXCR4 abolished the protective effects of SP1 silencing on LPS-induced injury in H9c2 cells. SP1 was also shown to enhance the promoter activity of CXCR4 by directly binding with the binding motif site – 109/–100 in CXCR4 promoter. Besides, downregulation of SP1 or CXCR4 blocked LPS-induced activation of the NF-кB signaling in H9c2 cells. Furthermore, inhibition of NF-кB signaling by DHMEQ abolished LPS-induced myocardial inflammation and apoptosis. In conclusion, silencing of SP1 protected H9c2 cells against LPS-induced injury by binding to the promoter of CXCR4 and suppressing the NF-κB signaling pathway. Hence, our findings provide evidence that manipulation of SP1 or CXCR4 may be an effective approach to promote prevention or recovery of septic myocardial injury, and thereby, may serve as a potential therapeutic strategy for sepsis.

GADD45B Is a Potential Diagnostic and Therapeutic Target Gene in Chemotherapy-Resistant Prostate Cancer

Background

Chemoresistance is the major cause of death in advanced prostate cancer (PCa), especially in metastatic PCa (mPCa). However, the molecular mechanisms underlying the chemoresistance of PCa remain unclear. Understanding the reason behind the drug resistance would be helpful in developing new treatment approaches.

Methods

The Cancer Genome Atlas, Gene Expression Omnibus datasets, and clinical samples were used to examine the correlation between growth arrest and DNA damage-inducible 45 beta (GADD45B) with clinical characteristics and prognosis. Lentiviral transfection was used to construct GADD45B overexpression cell lines. Hypoxic incubator, low serum medium, or docetaxel was used to build environmental stress model or chemotherapy cell model. The MTS assay and colony formation assay were used to test cell viability. Apoptosis and cell cycle were detected by flow cytometry. The RNA and protein levels of related biomarkers were tested by Western blotting and quantitative polymerase chain reaction. Bioinformatics analysis after RNA sequencing was performed to identify the possible mechanism of how GADD45B regulates chemotherapy resistance.

Results

GADD45B was related to distant metastasis but not to Gleason score, prostate-specific antigen level, T stage, or lymph node metastasis and indicated a good prognosis. The level of GADD45B increased significantly in PCa cells that faced environmental stress. It was found that a high level of GADD45B significantly enhanced the chemosensitivity. Furthermore, high GADD45B promoted cell apoptosis via mitogen-activated protein kinase (MAPK) pathway.

Conclusion

GADD45B promoted chemosensitivity of prostate cancer through MAPK pathway. GADD45B could serve as a diagnostic biomarker and therapeutic target for mPCa or chemotherapy-resistant patients.