Tumor Immunoassessment Resource (TIMER)
Gene expression levels of TRIB3 have been calculated using the TIMER database (http://timer.comp-genomics.org/). We selected the Gene_DE module and entered TRIB3 to obtain its mRNA expression in a pan-cancer landscape. Gene expression levels have been expressed as log2 TPMs (15, 16).
TRIB3 Expression Patterns in Human Pancarcinomas
Dysregulation of TRIB3 expression between various cancer types and normal tissues was investigated by combining normal tissue data from the GTEx database with data from The Cancer Genome Atlas (TCGA) (17, 18). The following cancers were obtained from the TCGA database: Head and Neck Squamous Cell Carcinoma (HNSC), Thyroid Carcinoma (THCA), Thymoma (THYM), Breast Invasive Carcinoma (BRCA), Oesophageal Carcinoma (ESCA), Lung Adenocarcinoma (LUAD), Lung Squamous Cell Carcinoma (LUSC), Mesothelioma (MESO), Stomach Adenocarcinoma (STAD), Colorectal Adenocarcinoma (COAD), Rectal Adenocarcinoma (READ), Liver Hepatocellular Carcinoma (LIHC), Pancreatic Anaplasmacytosis (PAAD), Pancreatic Adenocarcinoma (PAAD), Kidney Clear Cell Carcinoma (KIRC), Kidney Renal Pleomorphic Cell Carcinoma (KIRP), Kidney Eosinophilic Cell Carcinoma (KICH), Bladder Urothelial Carcinoma (BLCA), Prostate Adenocarcinoma (PRAD), Testicular Germ Cell Tumor (TGCT), Uterus Carcinoma of the Uterus Body and Endometrium (UCEC), Uterine Carcinoma (UCS), Ovarian Volvulus Cystic Carcinoma (OV), Adrenocortical Carcinoma (ACC), Squamous Cell Carcinoma of the Cervix (CESC), Skin Melanoma (SKCM), Sarcoma (SARC), Acute Myeloid Leukaemia (LAML), Diffuse Large B-cell Lymphoma (DLBC), Glioblastoma (GBM), Low Grade Glioma of the Brain (LGG), Pheochromocyte Cancer (PAC), Pheochromocytes (PA), and Pheochromocytoma and Paraganglioma (PCPG). All expression data underwent normalization using the transformation Log_2(TPM + 1).
Genomic Heterogeneity Score
We derived TRIB3 gene expression data from various types of sources and further screened primary blood-derived cancers-peripheral blood and primary tumor samples. In addition, we downloaded level 4 simple nucleotide variant datasets instrumented by MuTect2 software (19) from all TCGA samples on GDC (https://www.portal.gdc.cancer.gov/), as well as the Neoantigen or purity score for each tumor (20). We integrated the samples' TMB, NEO, and purity scores with the gene expression data and filtered out samples with an expression level of 0 (21, 22).
Construction of ROC
We also obtained pan-cancer statistical clinical data from the TCGA database and built receiver operating characteristic curves (ROCs) utilizing the "pROC" R package to evaluate the diagnostic ability of TRIB3 for 24 cancers (23).
Expression and localization characteristics of TRIB3
The mRNA expression spectrum of CHOL was obtained from the TCGA database and transformed into Log2 (TPM + 1) form after normalization. To analyze TRIB3 expression differences between tumor and neighboring non-tumor tissues, the R packages "stats" (version 4.2.1) and "car" (version 3.1-0) were utilized. Finally, the data were visualized using the R package "ggplot2" (version 3.3.5). In an attempt to further explore the localization of TRIB3 in CHOL, A single-cell RNA sequence analysis based on TRIB3 mRNA expression was conducted on the Tumor Immune Single-Cell Hub (Tisch, http://www.tisch.comp-genomics.org/) (24). In addition, CHOL_GSE138709 dataset was analyzed for TRIB3 levels of expression in various cell cluster.
Immune infiltration analysis
The CIBERSORT algorithm was applied in the evaluation of the immunologic infiltration of 22 immune cells using the "immuneeconv "R software package. The levels of immunologic infiltration were then compared between the high and low TRIB3-expressing cohorts. Subsequently, the Spearman method was utilized to determine the correlation among the level of immmunocyte infiltration and TRIB3 expression in the samples. The visualization were performed with the “ggplot2” and “ggClusterNet” in R. P-value < 0.05 was considered statistically significant.
We also utilized the online bioinformatics analysis platform BEST to integrate two datasets related to CHOL, such as GSE107943 and TCGA_CHOL, to detect the link between immmunocyte infiltration and immune-related gene sets. Specifically, we employed seven distinct algorithms (cibersort, epic, estimate, mcpcounter, quantiseq, timer, and xCELL) to assess immmunocyte infiltration patterns. Furthermore, we scrutinized the correlation between TRIB3 level and five categories of Immunomodulators separately, namely Antigen Presentation, Immunoinhibitor, Immunostimulator, Chemokine, and Receptor, within the context of the CHOL datasets analyzed.
Protein-protein interactive network construction and enrichment analysis
STRING website (https://www.string-db.org/) was utilized to create the protein–protein interaction (PPI) network of TRIB3 containing 20 related proteins. To examine the correlation between TRIB3 and these top 20 related-genes, the correlation analysis was performed with the Gene Expression Profiling Interactive Analysis 2nd Edition (GEPIA2, http://www.gepia2.cancer-pku.cn/#analysis) (25). Those genes with Pearson's coefficient greater than 0.3 and p-value less than 0.05 were chosen for Kyoto Encyclopedia of Genomes (KEGG) and Gene Ontology (GO) analyses. The results were visually processed with the "gplot2" (version 3.3.0) and "clusterProfiler" (version 3.14.2) R packages.
Differential expression and enrichment analyses
CHOL patients were categorized into highly-expressed and low-expressed groups based on the median expression level of TRIB3. The “limma” R oftware package was utilized to screen out the differentially expression genes (DEGs) between these two subsets, with the filtering threshold of DEGs set as p value less than 0.05 and |log2(Fold change)| >1.5(26). The heatmap displays the TOP 50 most significantly upregulated and downregulated genes. Following this, the DEGs were characterized by GO and KEGG analysis. The dataset "c2.cp.kegg.v7.4.symbols.gmt" containing gene sets was acquired from the Gene Set Enrichment Analysis (GSEA) (http://www.gsea-msigdb.org/gsea/index.jsp) to false discovery rates (FDR) for Differentially Expressed Genes (DEGs) between high- and low- TRIB3 level groups. GSEA also presents the calculation of the normalized enrichment score (NES), the results include the display of the Top 10 most significantly enriched pathways (27, 28).
Drug sensitivity analyses
We utilized the online bioconfidence analysis platform BEST (https://www.rookieutopia.com/app_direct/BEST/) to scrutinize various CHOL datasets, encompassing GSE107943 and TCGA_CHOL, within multiple drug sensitivity prediction repositories. The relationship between TRIB3 and drug sensitivity was explored utilizing three databases: GDSC (https://www.cancerrxgene.org/), PRISM (https://www.theprismlab.org/), and CTRP (https://www.portals.broadinstitute.org/ctrp/), with the results visualized through heatmaps.
Proteomic correlation analysis
The TCPA database was used to take samples from the TCGA project for tumor proteomic studies using reverse-phase protein arrays (RPPA) technology (http://tcpaportal.org/tcpa/), which we used to explore the mRNA expression of TRIB3 in CHOL in relation to the proteomic Correlation. We screened proteins with an absolute value of the correlation coefficient with TRIB3 greater than 0.3 and a p-value less than 0.05.
Culture of cells and transfection of siRNA
Cells used for the experiment at 37°C and 5% CO2 were grown in a humidified environment with nutrient solution selected from RPMI-1640 or high-sugar DMEM containing 10% fetal bovine serum (Gibco, USA).
TRIB3-siRNA#1, #2 and #3 for gene transfection were obtained from Shanghai GenePharma (Shanghai, China). The CHOL cell lines RBE and Hucc T1 (from Shanghai Cell Culture Preservation Center, China) were seeded into 6-well plates at a concentration of 3 × 105. The next day, when the cell fusion reached 60–70%, TRIB3-siRNA (100 nM) was transfected into the cells with TurboFect Transfection Reagent (Thermo Scientific, Waltham, MA, USA) (Table S1). 48 h later, we extracted the RNA from the cells and detected the relatively expressed level of TRIB3 mRNA.
Real-time Quantitative Reverse Transcription-PCR
RNA was isolated from cultivated cells with Trizol reagent (Invitrogen, Carlsbad, CA, USA) and reverse-transcribed to cDNA with an RNA reverse-transcription kit (Thermo Scientific, Waltham, MA, USA). qPCR was performed based on a qPCR kit (Takara SYBR Premix Ex Taq I, Tokyo, Japan) and Sangon Biotech (Shanghai, China) synthesized primers (see Table S2) for qPCR. We analyzed the results of the data with 2-ΔΔCT and normalized the TRIB3 expression levels.
Cell Counting Kit-8 Proliferation Assay
In each well of a 96-well plate, 1000 cells were placed. CCK-8 reagent (Dojindo Seed, Japan) was added directly into the culture medium at the specified times (24, 48, 72, 96 h). After that, the cells were incubated at 37°C for 2 h and the optional density (OD) value was calculated at 450 nm by an enzyme marker (BioTek Instruments, USA).
Flow cytometry apoptosis assay
All transfected cells were collected and made into single cell suspension cells/mL at a concentration of 1 × 106 using 1× binding buffer. Then, 100 µL of the cell suspension was mixed with 5 µL of PE and 5 µL of 7AAD stain for 15 minutes. Next, 400 µL of 1× binding buffer was added to each tube and the data was analysed by flow cytometry using FlowJo V10.
Wound Healing Assay
We inoculated a total number of 1 × 106 cells into a 6-well plate for 24 hours. The cells were then scratched onto a unilayer with a 200 µL pipette blade. Cell migration images captured at 0-, 24-, and 48-hours post-injury are representative. The decremental separation of the region of evoked damage was calculated and expressed as relative mobility, normalized to 0 hr power.
Transwell cell migration and invasion tests
Cell invasion and migration experiments were performed with Transwell chambers with or without matrix gel (BD Biosciences, San Jose, CA, USA). After transfection, cells were injected in the Transwell upper chamber, while the bottom chamber contained medium containing 20% FBS. Following 48 hours of incubation, cells in both chambers were immobilized with 4% paraformaldehyde solution, colored with 0.1% crystal violet, and imaged with a microscope. Migrating or invading cells were quantified using ImageJ platform.
Statistical analysis
Each experiment was repeated independently three times at least, and quantitative values were expressed in mean ± standard deviation. Statistical comparisons between the two groups were made by independent samples or paired t-tests, and multiple comparisons were made by one-way ANOVA when the data showed normal distribution and homoscedasticity. If these assumptions were not met, nonparametric tests were used. Visualization was performed using GraphPad Prism 8.0 and R Studio software, and statistical analysis was performed with SPSS 22.0 software. A level of significance at P < 0.05 was regarded as statistical significance.