Discussion

CENPN encoded proteins form nucleosome-associated complexes that are important for centromere assembly. CENPN binds to centromeres during the S and G2 phases and recruits other centromeric proteins22. Accurate chromosome segregation during mitosis is required for the proper transfer of genetic material from the mother to daughter cells. Missegregation of chromosomes can result in aneuploidy, a hallmark of cancer8. In humans, the histone H3 variant centromere protein A (CENPA) is present in the Functional centromeres. CENPA disruption or mutation results in failure of centromere formation23, 24. CENPN can recognize CENPA and regulate mitosis by forming the CENPA nucleosome-associated complex (NAC)25, 26. CENPN interacts with CENPA’s centromere-targeting domain of CENPA to facilitate centromere assembly27, and CENPN depletion leads to the loss of many other CENPs25, 28. Consequently, the CENPA nucleosome core region, which is necessary for centromere formation and chromosome segregation, is directly recognized by CENPN29. However, the mechanism of CENPN in STAD has not yet been reported, so it is of great significance to study the effect of CENPN in STAD.
TCGA and GTEx datasets were used in this study to evaluate the expression of CENPN in STAD. The evaluations revealed that STAD had higher CENPN expression than adjacent tumors (P < 0.05). We also examined CENPN expression in STAD paired samples from TCGA database. The results showed that STAD tissues had a greater level of CENPN expression than Matched normal tissues (P < 0.001). We verified this finding using immunohistochemistry. This is consistent with the high expression of CENPN in malignancies of the lungs, liver, nasopharynx, and mouth18, 19, 30, 31. The ROC curve also supports CENPN’s diagnostic value of CENPN. Additionally, we discovered that the degree of tumor invasion, TNM stage, and lymph node metastasis were substantially correlated with the level of CENPN expression in the tissues of patients with STAD, indicating that the abnormal expression of CENPN was intimately linked to the onset of STAD.
CENPN expression was found to be closely related to cell proliferation pathways such as”cell cycle,” ”DNA replication,” ”chromosome segregation,” and ”nuclear division” in our enrichment analysis. To validate this result, first we knocked down CENPN in AGS cells and discovered that depletion of CENPN significantly inhibited cell proliferation. Second, flow cytometry was used to detect changes in the cell cycle of AGS cells after CENPN knockdown. The results showed that knocked down of CENPN in AGS cells resulted in an increased percentage of G0-G1 cells (P < 0.05) and a significant decrease in the proportion of cells in the S and G2-M phases (P < 0.05). The S phase is the DNA synthesis phase that is critical for cell division and proliferation. These findings suggest that CENPN downregulation inhibits AGS cell proliferation. Studies have shown that CENPN knockdown promotes apoptosis in a variety of cancers17, 19 . This study hypothesizes that CENPN might have the same effect in STAD. Flow cytometry was performed to investigate the relationship between CENPN expression and apoptosis in AGS cells. The results revealed that CENPN knockdown significantly increased the apoptotic rate of AGS cells.This suggested that CENPN is involved in apoptosis in STAD.
Immune cells play a crucial role in controlling the malignant behavior of tumor cells32-34. Immune cell infiltration has been linked to the development and spread of cancer35, 36. In this study, we explored the association between CENPN expression and immune cell infiltration in STAD. These findings demonstrate a positive correlation between Th2 cells and NK CD56dim cells and CENPN expression.Instead, it negatively correlated with mast cells,pDC,NK cells ,and B cells. These findings imply that the regulation of tumor immunity may be significantly influenced by CENPN.
However, this study has certain limitations. First, confounding variables may have skewed the data from open databases. Second, the sample numbers were limited in this study, and more cases are required to validate an observation. Finally, further research is needed to determine the precise mechanism of CENPN in STAD.
In conclusion, our investigation showed that CENPN was upregulated in STAD tissues and that the degree of tumor invasion, TNM stage, and lymph node metastasis were significantly correlated with CENPN expression. The proliferation of STAD cells was inhibited by depletion of CENPN, which also decreased the percentage of cells in S and G2-M phases and increased apoptosis. Immune cell infiltration and CENPN expression Significantly correlated. Therefore, we believe that CENPN could be a possible therapeutic target for STAD.