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.