USP5 expression in human organs/tissues and pan-cancer
Initially, we examined the mRNA and protein expression levels of USP5 in various organs or tissues. The results obtained from consensus dataset created by combing the HPA and GTEx transcriptomics datasets showed that mRNA of USP5 mainly expressed in skeletal muscle, skin, tongue, parathyroid gland, testis, pons, esophagus, cerebral cortex, adrenal gland and thymus (Supplementary Fig. 1A, B). In addition, the protein of USP5 primarily expressed in cerebellum, testis, cerebral cortex, hippocampus, caudate, thyroid gland, parathyroid gland, adrenal gland, bronchus and lung demonstrated by the HPA dataset (Supplementary Fig. 1A, C).
Then, we analyzed the mRNA expression level of USP5 in pan-cancer. Unpaired analysis of USP5 mRNA expression between paracancerous tissues and cancers revealed that USP5 expressed significantly higher in BRCA (Breast invasive carcinoma), CHOL (Cholangiocarcinoma), COAD (Colon adenocarcinoma), ESCA (Esophageal carcinoma), HNSC (Head and Neck squamous cell carcinoma), KIRP (Kidney renal papillary cell carcinoma), LIHC (Liver hepatocellular carcinoma), LUAD (Lung adenocarcinoma), LUSC (Lung squamous cell carcinoma), PCPG (Pheochromocytoma and Paraganglioma), STAD (Stomach adenocarcinoma) and UCEC (Uterine Corpus Endometrial Carcinoma), and significantly lower in GBM (Glioblastoma multiforme), KICH (Kidney Chromophobe) and PRAD (Prostate adenocarcinoma). There was no obvious difference shown in BLCA (Bladder Urothelial Carcinoma), CESC (Cervical squamous cell carcinoma and endocervical adenocarcinoma), KIRC (Kidney renal clear cell carcinoma), PAAD (Pancreatic adenocarcinoma), READ (Rectum adenocarcinoma) and THCA (Thyroid carcinoma). ACC (Adrenocortical carcinoma), DLBC (Lymphoid Neoplasm Diffuse Large B-cell Lymphoma), LAML (Acute Myeloid Leukemia), LGG (Brain Lower Grade Glioma), MESO (Mesothelioma), OV (Ovarian serous cystadenocarcinoma), SARC (Sarcoma), SKCM (Skin Cutaneous Melanoma), THYM (Thymoma), TGCT (Testicular Germ Cell Tumors), UCS (Uterine Carcinosarcoma) and UVM (Uveal Melanoma) were unable to be analyzed due to the lack of sufficient paracancerous samples (Fig. 1A). Moreover, the paired sample analysis showed that compared with paracancerous tissues, USP5 was overexpressed in BLCA, BRCA, CHOL, ESCA, HNSC, KIRC, KIRP, LIHC, LUAD, LUSC and STAD. On the contrary, USP5 was decreased in KICH and PRAD. And no significantly differential expression of USP5 observed in COAD, PAAD, READ, THCA and UCEC (Fig. 1B). Given the lack of paracancerous tissues in some analysis, we further detected the expression differences of USP5 using the combination of TCGA and GTEx. And the results showed that low expression of USP5 was only observed in LAML, and high expression of USP5 was observed in ACC, BRCA, CESC, CHOL, COAD, DLBC, ESCA, GBM, HNSC, KIRP, LGG, LIHC, LUAD, LUSC, OV, PAAD, PCPG, PRAD, READ, SKCM, STAD, TGCT, THCA, THYM, UCEC and UCS. There was no difference shown in BLCA, KICH and KIRC. Analysis of MESO, SARC and UVM was not possible due to lack of sufficient normal samples (Fig. 1C). Furthermore, we used GEPIA2.0 to explore the effect of USP5 mRNA expression on patient’s pathological stages. And we found that the expression of USP5 was significantly correlated with the pathological stages of CESC, KIRC, LIHC, LUAD, OV and PAAD (Fig. 1D).
At last, we further explored the protein expression level of USP5 in pan-cancer using the National Cancer Institute’s CPTAC dataset and the IHC results provided by the HPA dataset. The result of CPTAC analysis indicated that the protein expression of USP5 was up-regulated and correlated with pathological stages in clear cell RCC (Renal cell carcinoma) and OV (Supplementary Fig. 2A, B). And the IHC results of the HPA showed that staining intensity of USP5 was greater in many cancers, mainly including BRCA, LIHC, OV, PRAD, READ and UCEC, which was consistent with the analysis result of the mRNA expression level of USP5 form TCGA + GTEx (Fig. 2A-F). Overall, USP5 was overexpressed in most cancers.
Usp5 Expression In Different Molecular Subtypes And Immune Subtypes Of Pan-cancer
We analyzed the correlation between USP5 expression and molecular or immune subtypes in pan-cancer from the TISIDB database. The results indicated that USP5 was expressed differently in 10 of 17 cancers for molecular subtypes, including BRCA (5 subtypes), COAD (4 subtypes), ESCA (5 subtypes), HNSC (4 subtypes), KIRP (4 subtypes), LGG (6 subtypes), LUSC (4 subtypes), OV (4 subtypes), PCPG (4 subtypes) and UCEC (4 subtypes) (Fig. 3A-J). Meanwhile, for immune subtypes (C1: wound healing, C2: IFN-gamma dominant, C3: inflammatory, C4: lymphocyte depleted, C5: immunologically quiet, C6: TGF-b dominant), we found that USP5 expression was significantly different in 14 of 30 cancers, including BLCA, BRCA, HNSC, KICH, KIRC, KIRP, LIHC, LUAD, LUSC, MESO, OV, PCPG, SKCM and STAD (Fig. 4A-N).
Diagnostic Value Of Usp5 In Pan-cancer
We plotted the receiver operating curve (ROC) to investigate the diagnostic value of USP5 in pan-cancer. And the ROC curve analysis demonstrated that USP5 had certain diagnostic accuracy (AUC > 0.7) in 20 cancer types, including ACC, BRCA, CESC, CHOL, COAD, DLBC, GBM, HNSC, KIRP, LGG, LIHC, LUAD, LUSC, OV, PAAD, READ, STAD, TGCT, THYM and UCS (Fig. 5A-T). Among them, USP5 had great diagnostic performance (AUC > 0.9) in BRCA, CHOL, DLBC, LGG, LUSC, PAAD and THYM.
Prognostic Value Of Usp5 In Pan-cancer
To evaluate the prognostic assessment value of USP5 in pan-cancer, we carried out the Cox proportional hazards model and Kaplan-Meier analysis. And the result showed that the high level of USP5 predicted poor OS of LAML, LIHC, LUAD, MESO, SKCM and UVM (Fig. 6A, B). For DSS, USP5 played a risk role for BLCA, COAD, LUAD, MESO, SKCM and UVM (Fig. 6A, C). Furthermore, patients with high expression of USP5 had shortened PFI in ACC, COAD, MESO and UVM (Fig. 6A, D).
Genetic Alteration Of Usp5 In Pan-cancer
To investigate the genetic mutations of USP5 in pan-cancer, we used cBioPortal online platform based on TCGA data. The highest frequency of USP5 alteration appeared in AML (Acute Myeloid Leukemia), ACC, BLCA, LGG, BRCA, CESC, CHOL and COADREAD. And mutation, amplification and deep deletion were the most common genetic alterations types of USP5 (Fig. 7A). In addition, we found 149 mutation sites with missense mutation as the main alteration type in USP5. For instance, a missense mutation within the UCH domain, P650L/S alteration was detected in one case of UCEC and two cases of SKCM (Fig. 7B). Then the correlation between the putative CNA of USP5 and its gene expression in pan-cancer was shown in Fig. 7C, D. Moreover, compared with the unaltered group, the gene alteration of AGAP10P, CHD4, VWF, NCAPD2, GPR162, LRRC23, PTPN6, ATN1, LAG3 and CD4 was more predominant in group with USP5 alteration (Fig. 7E). Last, we studied the effect of USP5 genetic alteration on the prognosis of patients in pan-cancer, and the result indicated that patients with USP5 alteration had poor PFS in pan-cancer (Fig. 7F), but not OS, DFS and DSS (Supplementary Fig. 3A-C).
Analysis Of The Methylation Level Of Usp5 In Pan-cancer
DNA methylation has been proved to play an essential role in the occurrence and progression of cancers. Using UALCAN database, we compared the methylation level of USP5 between normal and cancer tissues. We found that the promoter methylation level of USP5 decreased in most cancers, including BLCA, BRCA, CHOL, COAD, ESCA, HNSC, LIHC, LUAD, LUSC, PAAD, PRAD, READ, TGCT and UCEC (Fig. 8A-N). An obvious increase in the methylation level of USP5 was showed in KIRP, KIRC and THCA (Supplementary Fig. 4A). And the difference of the USP5 methylation level was not significant in CESC, GBM, PCPG, SARC, STAD and THYM (Supplementary Fig. 4B).
Immunogenomic Analyses Of Usp5 In Pan-cancer
Considering the critical role of immune infiltration and immune regulation in the oncology progress, we first applied CIBERSORT, CIBERSORT-ABS, EPIC, MCPCOUNTER, QUANTISEQ, TIDE, TIMER and XCELL algorithms to explore the correlation between USP5 expression and the infiltration level of different immune and endothelial cells in pan-cancer of TCGA. The result showed that USP5 expression was positively correlated with the infiltration of cancer-associated fibroblasts in CESC, HNSC and HNSC-HPV- (Fig. 9A). In addition, we discovered a positive correlation between USP5 expression and endothelial cell infiltration in COAD, HNSC-HPV+, SKCM-Metastasis and THCA, while negatively correlated with endothelial cell infiltration in BRCA, BrCA-basal and THYM (Fig. 9B).
Also, we observed that USP5 was correlated with most immune inhibitors and immune stimulators except for KIR2DL1, KIR2DL3 and TNFSF18 in pan-cancer (Supplementary Fig. 5A, B). In terms of MHCs, USP5 was positively associated with most MHCs in KIRC, KIRP and UVM, and negatively associated with most MHCs in ESCA, KICH, LUSC and TGCT (Supplementary Fig. 5C). Moreover, we found that USP5 showed certain correlation with majority of chemokines with the exception of CCL1, CCL16, CCL27, CCL24 and CCL25 in pan-cancer (Supplementary Fig. 5D). Meanwhile, a negative correlation between USP5 and most chemokine receptors could be found in the majority of malignant tumors especially in ESCA, KICH, LUSC and TGCT (Supplementary Fig. 5E).
Functional States Analysis Of Usp5 At Single Cell Levels
Using the CancerSEA, we investigated the functional states of USP5 at single cell levels in various cancers. The results indicated that USP5 was positively correlated with angiogenesis, differentiation, hypoxia, inflammation and metastasis, and negatively correlated with apoptosis, cell cycle, DNA damage, DNA repair, invasion, metastasis, quiescence and stemness (Fig. 10A). Then, the association between USP5 and specific cancer types was further examined. And we observed that USP5 showed positive correlation with hypoxia in LUAD; with metastasis in RCC; with differentiation, angiogenesis and inflammation in RB (Retinoblestoma). In contrast, USP5 negative correlated with DNA repair in ALL (Acute Lymphoblastic Leukemia); with stemness in PC (Prostate cancer); with cell cycle in CRC (Colorectal cancer); with DNA repair, cell cycle and DNA damage in RB (Retinoblestoma); with DNA repair, DNA damage, apoptosis, invasion, metastasis and quiescence in UM (Uveal Melanoma) (Fig. 10B-H). Additionally, T-SNE diagrams were used to display USP5 expression profiles at single cell levels from ALL, LUAD, RCC, PC, CRC, RB and UM (Fig. 10I-O).
Functional Enrichment Analysis Of Usp5 In Pan-cancer
Finally, we screened out the USP5 co-expressed genes for a series of pathway enrichment analyses to understand the molecular mechanism of the USP5 gene in carcinogenesis and development. We first collected 179 molecules that interacted with USP5 via the BioGRID web service (Fig. 11A). Then we used GEPIA to acquire the top 100 USP5 co-expressed genes in pan-cancer. Among these, MLF2, COPS7A, PEX5, DDX47, STRAP and MRPL51 displayed strong correlations with USP5 in most cancer types (Fig. 11B, C). Furthermore, GO and KEGG enrichment analyses were used to reveal that USP5 co-expressed genes played a critical role in the regulation of spliceosome, RNA splicing, catalytic activity acting on RNA and histone binding in tumor pathogenesis (Fig. 11D).