Overexpression of Apolipoprotein C1 (APOC1) in Clear Cell Renal Cell Carcinoma and Its Prognostic Significance

Upregulation of APOC1 Promotes Colorectal Cancer Progression and Serves as a Potential Therapeutic Target Based on Bioinformatics Analysis

Background

Approximately 10% of cancer patients worldwide have colorectal cancer (CRC), a prevalent gastrointestinal malignancy with substantial mortality and morbidity. The purpose of this work was to investigate the APOC1 gene's expression patterns in the CRC tumor microenvironment and, using the findings from bioinformatics, to assess the biological function of APOC1 in the development of CRC.

Methods

The TCGA portal was employed in this investigation to find APOC1 expression in CRC. Its correlation with other genes and clinicopathological data was examined using the UALCAN database. To validate APOC1's cellular location, the Human Protein was employed. In order to forecast the relationship between APOC1 expression and prognosis in CRC patients, the Kaplan-Meier plotter database was used. TISIDB was also employed to evaluate the connection between immune responses and APOC1 expression in CRC. The interactions of APOC1 with other proteins were predicted using STRING. In order to understand the factors that contribute to liver metastasis from CRC, single-cell RNA sequencing (scRNA-seq) was done on one patient who had the disease. This procedure included sampling preoperative blood and the main colorectal cancer tissues, surrounding colorectal cancer normal tissues, liver metastatic cancer tissues, and normal liver tissues. Finally, an in vitro knockdown method was used to assess how APOC1 expression in tumor-associated macrophages (TAMs) affected CRC cancer cell growth and migration.

Results

When compared to paracancerous tissues, APOC1 expression was considerably higher in CRC tissues. The clinicopathological stage and the prognosis of CRC patients had a positive correlation with APOC1 upregulation and a negative correlation, respectively. APOC1 proteins are mostly found in cell cytosols where they may interact with APOE, RAB42, and TREM2. APOC1 was also discovered to have a substantial relationship with immunoinhibitors (CD274, IDO1, and IL10) and immunostimulators (PVR, CD86, and ICOS). According to the results of scRNA-seq, we found that TAMs of CRC tissues had considerably more APOC1 than other cell groups. The proliferation and migration of CRC cells were impeded in vitro by APOC1 knockdown in TAMs.

Conclusion

Based on scRNA-seq research, the current study shows that APOC1 was overexpressed in TAMs from CRC tissues. By inhibiting APOC1 in TAMs, CRC progression was reduced in vitro, offering a new tactic and giving CRC patients fresh hope.

Decreased APOC1 expression inhibited cancer progression and was associated with better prognosis and immune microenvironment in esophageal cancer

Several studies have demonstrated the involvement of apolipoprotein C1 (APOC1) in multiple cancers. However, the role of APOC1 in esophageal cancer (ESCA) has not been elucidated. Hence, we examined the expression of APOC1 in ESCA tissues acquired from The Cancer Genome Atlas (TCGA) database and clinical samples from our hospital. An investigation of the association of APOC1 with the clinicopathological characteristics, prognosis, and diagnosis of ESCA was carried out on the basis of survival, receiver operating characteristics, and correlation analyses. Gene ontology, KEGG analysis, and protein-protein interaction network showed that co-expressed APOC1 genes were involved in the functions, mechanisms, and action network. The effects of APOC1 expression on ESCA cells were explored using CCK-8, migration and invasion assays. The relationship between APOC1 expression and ESCA immune-infiltrating cells and cell markers were examined using correlation analysis. We found that APOC1 was overexpressed in TCGA ESCA tissues and the same was validated in clinical ESCA tissues, with the area under the curve for APOC1 being 0.887. Overexpression of APOC1 was associated with short overall survival, disease-specific survival, progression-free interval, T stage, pathological stage, body mass index, and histological grade. Inhibition of APOC1 expression significantly reduced the proliferation, migration, and invasion of ESCA cells. Furthermore, APOC1 expression positively correlated with the ESTIMATE, immune, and stromal scores in ESCA. Overexpression of APOC1 correlated with the tumor purity, B cells, T helper cells, natural killer cells, cytotoxic cells, and other immune cells. Moreover, APOC1 was involved in ESCA progression via T cell receptor, B cell receptor, and other immune signaling pathways. Thus, APOC1 overexpression is expected to be a biomarker for dismal prognosis and diagnosis of ESCA. Inhibition of APOC1 expression significantly reduced the proliferation, migration, and invasion of ESCA cells. Overexpression of APOC1 was associated with the immune microenvironment in ESCA. Thus, APOC1 may be an efficient biomarker for proper prognosis and diagnosis of ESCA.

Prognosis-related genes participate in immunotherapy of renal clear cell carcinoma possibly by targeting dendritic cells

Tumor immunotherapy has become one of the most promising approaches to tumor treatment. This study aimed to screen genes involved in the response of clear cell renal cell carcinoma (ccRCC) to immunotherapy and analyze their function. Based on the Gene Expression Omnibus and The Cancer Genome Atlas datasets, we screened out nine differentially expressed genes (TYROBP, APOC1, CSTA, LY96, LAPTM5, CD300A, ALOX5, C1QA, and C1QB) associated with clinical traits and prognosis. A risk signature constructed by these nine genes could predict the survival probability for patients at 1 year, 3 years, and 5 years. The immune checkpoint blockade response rate in the high-risk group was significantly higher than in the low-risk group (49.25% vs. 24.72%, p ≤ 0.001). The nine prognosis-related genes were negatively correlated with activated dendritic cells in the low-risk group but not in the high-risk group. qRT-PCR, immunohistochemistry, and immunofluorescence showed that the nine prognosis-related genes were associated with dendritic cell activity and the PD-1 positive staining rate. In conclusion, the nine prognosis-related genes have a high prognostic value. The patients in the high-risk group were more likely to benefit from immunotherapy, and the mechanism might be related to the release of dendritic cell-mediated immunosuppression.

Z-DNA-Containing Long Terminal Repeats of Human Endogenous Retrovirus Families Provide Alternative Promoters for Human Functional Genes

Transposable elements (TEs) account for approximately 45% of the human genome. TEs have proliferated randomly and integrated into functional genes during hominoid radiation. They appear as right-handed B-DNA double helices and slightly elongated left-handed Z-DNAs. Human endogenous retrovirus (HERV) families are widely distributed in human chromosomes at a ratio of 8%. They contain a 5'-long terminal repeat (LTR)-gag-pol-env-3'-LTR structure. LTRs contain the U3 enhancer and promoter region, transcribed R region, and U5 region. LTRs can influence host gene expression by acting as regulatory elements. In this review, we describe the alternative promoters derived from LTR elements that overlap Z-DNA by comparing Z-hunt and DeepZ data for human functional genes. We also present evidence showing the regulatory activity of LTR elements containing Z-DNA in GSDML. Taken together, the regulatory activity of LTR elements with Z-DNA allows us to understand gene function in relation to various human diseases.

Shared Genetic Basis and Causal Relationship Between Television Watching, Breakfast Skipping and Type 2 Diabetes: Evidence From a Comprehensive Genetic Analysis

Background

Epidemiological investigations have established unhealthy lifestyles, such as excessive leisurely sedentary behavior (especially TV/television watching) and breakfast skipping, increase the risk of type 2 diabetes (T2D), but the causal relationship is unclear. We aimed to understand how single nucleotide variants contribute to the co-occurrence of unhealthy lifestyles and T2D, thereby providing meaningful insights into disease mechanisms.

Methods

Combining summary statistics from genome-wide association studies (GWAS) on TV watching (N = 422218), breakfast skipping (N = 193860) and T2D (N = 159208) in European pedigrees, we conducted comprehensive pairwise genetic analysis, including high-definition likelihood (HDL-method), cross-phenotype association studies (CPASSOC), GWAS-eQTL colocalization analysis and transcriptome-wide association studies (TWAS), to understand the genetic overlap between them. We also performed bidirectional two-sample Mendelian randomization (MR) analysis for causal inference using genetic instrumental variables, and two-step MR mediation analysis was used to assess any effects explained by body mass index, lipid traits and glycemic traits.

Results

HDL-method showed that T2D shared a strong genetic correlation with TV watching (rg = 0.26; P = 1.63×10-29) and skipping breakfast (rg = 0.15; P =2.02×10-6). CPASSOC identifies eight independent SNPs shared between T2D and TV watching, including one novel shared locus. TWAS and CPASSOC showed that shared genes were enriched in lung, esophageal, adipose, and thyroid tissues and highlighted potential shared regulatory pathways for lipoprotein metabolism, pancreatic β-cell function, cellular senescence and multi-mediator factors. MR showed TV watching had a causal effect on T2D (βIVW = 0.629, PIVW = 1.80×10-10), but no significant results were observed between breakfast skipping and T2D. Mediation analysis provided evidence that body mass index, fasting glucose, hemoglobin A1c and high-density lipoprotein are potential factors that mediate the causal relationship between TV and T2D.

Conclusions

Our findings provide strong evidence of shared genetics and causation between TV watching and T2D and facilitate our identification of common genetic architectures shared between them.