Studies on the KPNA family have recently started to increase. However, reports of the KPNAs proteins in gastric cancer are relatively rare. The KPNA1 was the first to be reported on its involvement in drug transport into cell membranes [24]. It was reported to block some nuclear translocation functions in breast cancer cells in concert with other family members KPNA5/6 [5]. Here in the article, it was found that both transcript and protein contents of KPNA1 were higher in gastric cancer tissues than in paraneoplastic tissues and remarkably linked to OS, FP, and PPS as well as involved in immune invasion of tumor cells. Therefore, it was evident that KPNA1 has potential to become a new oncotarget in gastric cancer.
The existing reports showed that elevated expression of KPNA2 is linked to poor prognosis in gastric cancer [8, 25], and the results obtained in these studies were also consistent. The KPNA2 was highly expressed for both mRNA and protein expression, However, the correlation with the clinical stage was not very high, whereas the AUC curve showed high confidence, and the KM curve exhibited that the prognosis of the gene was linked to OS, FP, and PPS. Further, it was involved in tumor invasion of B cell, CD4 + T cell, and many other immune cells. Therefore, it was evident that KPNA2 can be utilized as a molecular marker for diagnosis of gastric cancer.
Previously, KPNA3 was reported to be highly expressed in colorectal cancer [10], whereas the current study exhibited that KPNA3 was also highly expressed in both colorectal and gastric cancers, and the difference in the level of mRNA expression was relatively significant. Results of PCR experiments showed that the difference in mRNA expression between cancer and paracancerous tissues was statistically significant, whereas the result of WB also supported the high expression of KPNA3 protein in gastric cancer. From the plotted survival curve, it was found that harboring higher KPNA3 expression had a dismal prognosis in contrast with normal individuals. The invasion of B cell, dendritic cell, CD8 + T cell, neutrophils, and CD4 + T cells in gastric cancer tissues was also linked to KPNA3 expression. Therefore, it was evident that KPNA3 is important in dragonizing gastric cancer.
It has been suggested that the knockdown of KPNA4 attenuated the metastasis of prostate cancer and its overexpression also promoted proliferation and invasion of papillary thyroid cancer [11, 13]. This research work demonstrated that the difference in KPNA4 expression between cancer and paraneoplastic tissues was statistically significant, and this result was consistent with those of PCR, WB, and IHC. Furthermore, the invasion of numerous immune cells B cell, macrophages, CD8 + T cell, along with CD4 + T cells was also linked to the expression of KPNA4. Therefore, it can be concluded that the present study can be a useful marker for the diagnosing gastric cancer and offer a reference for the diagnosis along with treatment of gastric cancer.
It has been suggested that elevated expression of KPNA5 is inversely linked to overall survival rate of individuals with breast cancer [26]. The current study demonstrated that the difference in KPNA5 expression in gastric cancer and non-malignant gastric tissues was not statistically significant, but there was a significant correlation with the clinical stage of gastric cancer. Further, it was found that KPNA5 expression at the transcript and protein levels in human gastric cancer tissues was remarkably different from that in non-malignant gastric mucosal tissues.
From the KM curves, it was evident that elevated expression of KPNA5 was negatively linked to the survival rate. Further, there was a remarkable immune invasion of CD8 + T cells in tissues with high expression of KPNA5 gene. It was hence suggested that KPNA5 expression in gastric malignant tissues has an indispensable role and participates in the immune invasion of tumors, thus can offer a basis for the diagnosis of gastric cancer from a certain perspective.
The KPNA6 has been previously reported to be involved in E2 signaling in breast cancer [5], and the present research work also established that KPNA6 was expressed differently in gastric mucosa and gastric cancer tissues at the RNA level as well as at the protein level with statistical significant difference in expression. Results of the survival curve, exhibited that high expression of KPNA6 was inversely linked to OS, FP, and PPS in patients with gastric cancer and was statistically significant. The CD8 + T and neutrophil cell invasion in cancer tissues were remarkably linked to the expression of the gene. Therefore, it is evident that KPNA6 could be an important marker in the detection and treatment of gastric cancer.
It has been reported that silencing KPNA7 can inhibit malignant properties of pancreatic cancer in vitro [14]. In this premise, it was found that the differences in the expression of KPNA7 at RNA along with protein levels in non-malignant gastric tissues and gastric cancer tissues were remarkably different. From the KM curves, it was shown that high expression of KPNA7 was negatively and statistically linked to OS, FS, and PPS in the patients, as well as positively and statistically linked to CD8 + T cell, neutrophils, CD4 + T cell, and macrophage invasion in the cancer tissues.
Herein, the KPNAs family has a mutation rate of between 0.6 and 7%, and the string database showed that the KPNAs family molecules interacted very closely with each other. The GO and KEGG analyses show that the biological processes of KPNAs are mainly in the regulation of host morphology or physiology by viruses and symbionts, NLS- carrying proteins into the nucleus, regulation of host processes by viruses, and enrichment of host processes by symbionts. The main functions of the KPNAs family are focused on the activity of nucleocytic transport carriers, protein import into the nucleus, nuclear transport and signal sequence binding, cell-cell junction organization, and viral regulation of the host processes.