CPLX2 is a novel tumor suppressor and improves the prognosis in glioma.

BACKGROUND: Glioma is a type of malignant cancer that affect the central nervous system. New predictive biomarkers have been investigated in recent years, but the clinical prognosis for glioma remains poor. The function of CPLX2 in glioma and the probable molecular mechanism of tumor suppression were the focus of this investigation. METHODS: The glioma transcriptome profile was downloaded from The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases for analysis of CPLX2 expression in glioma. RT-qPCR was performed to detect the expression of CPLX2 in 68 glioma subjects who have been followed up. Kaplan-Meier survival analyses were conducted to assess the effect of CPLX2 on the prognosis of glioma patients. The knockdown and overexpressed cell lines of CPLX2 were constructed to investigate the impact of CPLX2 on glioma. The cell growth, colony formation, and tumor formation in xenograft were performed. RESULTS: The expression of CPLX2 was downregulated in glioma and was negatively correlated with the grade of glioma. The higher expression of CPLX2 predicted a longer survival, as indicated by the analysis of Kaplan-Meier survival curves. Overexpressed CPLX2 impaired tumorigenesis in glioma progression both in vivo and in vitro. Knocking down CPLX2 promoted the proliferation of glioma cells. The analysis of GSEA and co-expression analysis revealed that CPLX2 may affect the malignancy of glioma by regulating the hypoxia and inflammation pathways. CONCLUSIONS: Our data indicated that CPLX2 functions as a tumor suppressor and could be used as a potential prognostic marker in glioma.

Highly expressed RPLP2 inhibits ferroptosis to promote hepatocellular carcinoma progression and predicts poor prognosis.

BACKGROUND: RPLP2, an integral part of ribosomal stalk, plays an important role in the tumorigenesis of various cancers. However, its specific effect on HCC remains elusive. METHODS: TCGA, GTEx, HCCDB, HPA, UALCAN, MethSurv, TISIDB, K-M plotter, FerrDb, RNAactDrug, STRING, Cytoscape and R studio were conducted for bioinformatics analysis. RPLP2 expression level in HCC was verified by IHC and western blot. IHC was used to demonstrate the immune cell infiltration. Functional experiments including CCK8, transwell and colony formation assays, and nude mice xenograft model were performed for in vitro and in vivo validation. Western blot, IHC, CCK8 assay and detection of GSH and lipid ROS were adopted to determine the effect of RPLP2 on the ferroptosis of HCC cells. RESULTS: Here, we demonstrate that elevated level of RPLP2 is strongly associated with advanced clinicopathologic features, and predicts poor prognosis of HCC patients. Additionally, DNA methylation level of RPLP2 decreases in HCC, and significantly correlates with patients outcome. Moreover, high RPLP2 expression level is linked closely to the unfavorable immune infiltration. Most importantly, RPLP2 positively associates with ferroptosis suppressor GPX4, and inhibition of RPLP2 could lead to the acceleration of ferroptosis to suppress tumor progression of HCC. Last, drug sensitivity analysis predicts many drugs that potentially target RPLP2. CONCLUSION: Together, our study reveals previous unrecognized role of RPLP2 in HCC, and provides new regulatory mechanism of ferroptosis, indicating RPLP2 may be a novel therapeutic target for HCC.

The DUBA-SLC7A11-c-Myc axis is critical for stemness and ferroptosis.

Ferroptosis is characterized by the accumulation of lipid peroxidation as a unique iron-dependent cell death. However, the interplay between stemness and ferroptosis remains unknown. Here, we demonstrate that undifferentiated cells are more sensitive to ferroptosis than differentiated cells, and cystine transporter SLC7A11 protein is highly up-regulated by deubiquitinase DUBA in differentiated cells. Additionally, DUBA promotes stemness by deubiquitinating SLC7A11. Moreover, SLC7A11 drastically increases the expression of c-Myc through cysteine, the combination of sorafenib and c-Myc inhibitor EN4 has a synergetic effect on cancer therapy. Together, our results reveal that enhanced stemness increases the susceptibility to ferroptosis, and the DUBA-SLC7A11-c-Myc axis is pivotal for differentiated cancer stem cells (CSCs) resistant to ferroptosis, providing a promised targets to eradicate CSCs through ferroptosis.

The ubiquitin-specific protease 5 mediated deubiquitination of LSH links metabolic regulation of ferroptosis to hepatocellular carcinoma progression.

Epigenetic regulators and posttranslational modifications of proteins play important roles in various kinds of cancer cell death, including ferroptosis, a non-apoptotic form of cell death. However, the interplay of chromatin modifiers and deubiquitinase (DUB) in ferroptosis remains unclear. Here, we found that ubiquitin-specific protease 5 (USP5) is regarded as a bona fide DUB of lymphoid-specific helicase (LSH), a DNA methylation repressor, in hepatocellular carcinoma (HCC). Functional studies reveal that USP5 interacts with LSH and stabilizes LSH by a deubiquitylation activity-dependent process. Furthermore, the USP5-mediated deubiquitination of LSH facilitates the tumorigenesis of HCC by upregulating solute carrier family 7 member 11 (SLC7A11) to suppress ferroptosis of liver cancer cells. Moreover, the USP5 inhibitor degrasyn inhibits DUB activities of USP5 to LSH to suppress the progression of HCC. Additionally, USP5 and LSH are positively correlated and both are overexpressed and linked to poor prognosis in HCC patients. Together, our findings show that USP5 interacts with LSH directly and enhances LSH protein stability through deubiquitination, which, in turn, promotes the development of HCC by suppressing ferroptosis of liver cancer cells, suggesting that USP5 may be a potential therapeutic target for HCC.

A pan-cancer analysis of the role of USP5 in human cancers.

Posttranslational modifications (PTM) such as acetylation, deubiquitination, and phosphorylation of proteins, play important roles in various kinds of cancer progression. Ubiquitin-specific proteinase 5 (USP5), a unique member of deubiquitinating enzymes (DUBs) which recognizes unanchored polyubiquitin specifically, could regulate the stability of many tumorigenesis-associated proteins to influence cancer initiation and progression. However, the diverse biological significance of USP5 in pan-cancer has not been systematically and comprehensively studied. Here, we explored the role of USP5 in pan-cancer using The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) database, and we also acquired and analyzed data via various software and web platforms such as R, GEPIA2.0, HPA, TISIDB, cBioPortal, UALCAN, TIMER 2.0, CancerSEA and BioGRID. USP5 expression was high in most cancers and differed significantly in different molecular and immune subtypes of cancers. In addition, USP5 had certain diagnostic value in multiple cancers, and high expression of USP5 generally predicted poor prognosis for cancer patients. We also found that the most frequent genetic alterations type of USP5 was mutation, and the DNA methylation level of USP5 decreased in various cancers. Furthermore, USP5 expression correlated with cancer-associated fibroblasts (CAFs), endothelial cells (EC) and genetic markers of immunodulators in cancers. Moreover, the result from single cell sequencing showed that USP5 could regulate several tumor biological behaviors such as apoptosis, DNA damage and metastasis. Gene enrichment analysis indicated "spliceosome" and "RNA splicing" may be the critical mechanism for USP5 to involve in cancer. Taken together, our study elucidates the biological significance of USP5 in the diagnosis, prognosis and immune in human pan-cancer.

Mutations and expressions of breast cancer 1/2 in lung cancer.

BACKGROUND: Breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) tumor suppressor genes play crucial roles in DNA repair and regulation of transcription. Mutations in these genes are closely associated with the occurrence of cancers. However, the mutation status of BRCA gene in central south Chinese lung cancer patients remains unclear, and its expression levels in lung cancer also need to be further explored. METHODS: In this study, we use next-generation sequencing (NGS) technology to analyze the BRCA genes mutations in 462 central south Chinese lung cancer patients. Public databases including cBioportal, Catalogue Of Somatic Mutations In Cancer (COSMIC), The Cancer Genome Atlas (TCGA), Human Protein Atlas (HPA) and Expression Profiling Interactive Analysis (GEPIA) are also applied to explore the expression level and mutation status of BRCA in lung cancer patients and their relationships with the prognosis. RESULTS: We found that the mutation rate of BRCA1/2 in central south Chinese lung cancer patients is 4.3% and 6.5% respectively, and missense mutations account for the majority in both BRCA1/2, which are similar to the international status of BRCA1/2 from public databases. In addition, 45 novel mutations of BRCA1/2 in lung cancer are reported in this study. Furthermore, we find that the BRCA2 mutations are negatively correlated with overall survival rate in lung cancer using cBioportal. Last, we demonstrate that both of the mRNA and protein levels of BRCA1/2 are upregulated in lung cancer, and the elevated mRNA expression levels are positively linked with poor prognosis. CONCLUSION: In general, our study better complements knowledge of the BRCA1/2 mutation status in the Chinese lung cancer patients, and firstly reveals the association between BRCA1/2 expression levels and prognosis of lung cancer patients, which may provide great value for the early diagnosis and clinical treatment of lung cancer.

AhR Promotes the Development of Non-small cell lung cancer by Inducing SLC7A11-dependent Antioxidant Function.

Objective: Aryl hydrocarbon receptor (AhR) is a transcription factor. It is reported that AhR is associated with non-small cell lung cancer (NSCLC), but the mechanisms underlying this relationship remain unclear. Therefore, we investigated the role of AhR in NSCLC to elucidate the underlying mechanisms. Methods: We collected clinical lung cancer samples and constructed AhR overexpression and knockdown cell lines to investigate the tumorigenicity of AhR in vivo and in vitro. Furthermore, we performed a ferroptosis induction experiment and chromatin immunoprecipitation experiment. Results: AhR was highly expressed in NSCLC tissue. AhR knockdown cells showed ferroptosis related phenomenon. Furthermore, Chromatin immunoprecipitation confirmed the correlation between AhR and solute carrier family 7 member 11 (SLC7A11) and ferroptosis induction experiment confirmed that AhR affects ferroptosis via SLC7A11. Specifically, AhR regulates ferroptosis-related SLC7A11, which affects ferroptosis and promotes NSCLC progression. Conclusions: AhR promoted NSCLC development and positively correlated with SLC7A11, affecting its actions. AhR bound to the promoter region of SLC7A11 promotes NSCLC by activating SLC7A11 expression, improving the oxidative sensitivity of cells, and inhibiting ferroptosis. Thus, AhR affects ferroptosis in NSCLC by regulating SLC7A11, providing foundational evidence for novel ferroptosis-related treatments.