Agmatinase facilitates the tumorigenesis of pancreatic adenocarcinoma through the TGFβ/Smad pathway

[Identification of potential pathogenic genes of intestinal metaplasia based on transcriptomic sequencing and bioinformatics analysis]

OBJECTIVE

To explore the potential pathogenic genes of intestinal metaplasia.

METHODS

Twenty-one patients with intestinal metaplasia admitted to the Department of Gastroenterology at the Second Affiliated Hospital of Anhui University of Chinese Medicine from January, 2022 to June, 2022, and 21 healthy subjects undergoing gastroscopic examination during the same period were enrolled in this study. All the participants underwent gastroscopy and pathological examination, and gastric tissue samples were collected for transcriptome sequencing to screen for differentially expressed genes (DEGs). The biological functions of the DEGs were analyzed using bioinformatics analysis, and qRT-PCR was used to validate the results.

RESULTS

Transcriptomic sequencing identified a total of 1373 DEGs, including 827 upregulated and 546 downregulated ones. The top 6 upregulated genes (AGMAT, CCL25, FABP1, CDX1, SPINK4, and MUC2), ranked based on their significance and average expression level, were selected for validation, and qRT-PCR showed significant upregulation of their mRNAs in the gastric tissues of patients with intestinal metaplasia (P < 0.05).

CONCLUSION

AGMAT, CCL25, FABP1, CDX1, SPINK4, and MUC2 participate in the occurrence and development of intestinal metaplasia, and may serve as potential biomarkers for diagnosing intestinal metaplasia.

Suppression of the KRAS-NRF2 axis shifts arginine into the phosphocreatine energy system in pancreatic cancer cells

In pancreatic ductal adenocarcinomas (PDAC), the KRASG12D-NRF2 axis controls cellular functions such as redox homeostasis and metabolism. Disruption of this axis through suppression of NRF2 leads to profound reprogramming of metabolism. Unbiased transcriptome and metabolome analyses showed that PDAC cells with disrupted KRASG12D-NRF2 signaling (NRF2-/- cells) shift from aerobic glycolysis to metabolic pathways fed by amino acids. Metabolome, RNA-seq and qRT-PCR analyses revealed a blockade of the urea cycle, making NRF2-/- cells dependent on exogenous arginine for survival. Arginine is channeled into anabolic pathways, including the synthesis of phosphocreatine, which generates an energy buffer essential for cell growth. A similar switch was observed in tumor clones that had survived FOLFIRINOX therapy or blockade of KRAS signaling. Inhibition of the creatine pathway with cyclocreatine reduced both ATP and invasion rate in 3D spheroids from NRF2-deficient PDAC cells. Our study provides basis for the rational development of combination therapies for pancreatic cancer.

A polyamine metabolism risk signature for predicting the prognosis and immune therapeutic response of kidney cancer

Background

Polyamine metabolism is critically involved in the proliferation and metastasis of tumor cells, including in kidney renal clear cell (KIRC) cancer. However, the molecular mechanisms underlying the effect of polyamines in KIRC cancer remain largely unknown.

Methods

The messenger RNA (mRNA) expression profile of KIRC was downloaded from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and ArrayExpress database. Differential expression analysis was performed with the "limma" package in R. Univariate Cox regression and multivariable Cox regression were used to estimate correlation between variables and prognosis. Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was employed to screen variables and construct a risk signature. A nomogram model was established using the risk signature and clinical variables. Receiver operating characteristic (ROC), calibration curve, and decision curve analysis (DCA) were used to assess the predicted accuracy and clinical benefit of the model.

Results

We identified nine differentially expressed polyamine metabolism-related genes (PMRGs) in TCGA-KIRC. Of these, six were closely associated with patients' outcomes. These six genes participated in different pathways and originated from different cell types within the tumor microenvironment (TME). Using the mRNA expression values of these genes, we constructed a 4-gene PMRG risk signature. Patients with high PMRG risk exhibited worse outcomes, and our analysis showed that the PMRG risk signature was an independent prognostic factor when clinical information was used as a covariate. We also found that multiple immune- or metabolism-related pathways were differentially enriched in high or low PMRG risk groups, suggesting that altering these pathways could lead to different clinical outcomes. Finally, in two external datasets, we found that the PMRG risk signature could predict the response of patients to immune therapy.

Conclusions

In summary, our study identified several potentially important PMRGs in KIRC and constructed a practical risk signature, which could serve as a foundation for further development of polyamine metabolism-based targeted therapies for KIRC.

miR‑151a‑5p promotes the proliferation and metastasis of colorectal carcinoma cells by targeting AGMAT

Colorectal carcinoma (CRC) is one of the most common types of digestive cancer. It has been reported that the ectopic expression of microRNAs (miRs) plays a critical role in the occurrence and progression of CRC. In addition, it has also been suggested that miR‑151a‑5p may serve as a useful biomarker for the early detection and treatment of different types of cancer and particularly CRC. However, the specific effects and underlying mechanisms of miR‑151a‑5p in CRC remain elusive. The results of the current study demonstrated that miR‑151a‑5p was upregulated in CRC cell lines and clinical tissues derived from patients with CRC. Functionally, the results showed that miR‑151a‑5p significantly promoted CRC cell proliferation, migration and invasion. Additionally, dual luciferase reporter assays verified that agmatinase (AGMAT) was a direct target of miR‑151a‑5p and it was positively associated with miR‑151a‑5p expression. Mechanistically, miR‑151a‑5p could enhance the epithelial‑mesenchymal transition of CRC cells. Taken together, the results of the current study revealed a novel molecular mechanism indicating that the miR‑151a‑5p/AGMAT axis could serve a crucial role in the regulation of CRC and could therefore be considered as a potential therapeutic strategy for CRC.