ANAXs, as a Ca2+-dependent, phospholipid-binding protein super family, have been reported in numerous types of human cancer, and have participated in a wide variety of biological activities, such as tumorigenesis, progression and resistance to chemotherapeutic agents3,30. However, a further comprehensive bioinformatics analysis of ANAXs in KIRC has yet to be performed. In the present study, we analyzed the relationship between different ANAX factors expression and prognoses (OS and RFS) of KIRC for the first time. We hope that our findings may help create a foundation to better understand and improve current therapies and prognostic accuracy for patients with KIRC.
ANXA1 is known as an anti-inflammatory protein,but recognized to have a broader role in tumor cell biology beyond inflammation alone. ANXA1, located on the human chromosome 9q21.13, is the first characterized member of the super-family12. Transposition of ANXA1, which was found in Esophagus cancer, could affect the activities of arachidonic acid metabolism31. However, It’s more likely a double-edged sword due to its numerous and sometimes opposite functions. Yamanoi et al18 found that knockdown of ANXA1 inhibits the proliferation, migration, invasion and adhesion of kidney carcinoma cells. We first used the oncomine databases to reveal that ANXA1 mRNA expression level was significantly higher in KIRC tissues than that in normal tissues. However, its expression didn’t correlate with specific clinical features in KIRC. Using the Kaplan-Meier Plotter,we estimate the prognostic value of ANXA1 in patients with KIRC. The patients with KIRC with high mRNA level of the ANXA1 was predicted to have a lower RFS.
The ANXA2 monomer exists in cell cytoplasm and heterotetramer complexed with S100A10 which exists on cell membranes. Sadashiv et al32 reported that moderate immune expression of ANXA2 was found in the proximal convoluted tubules which were considered as the origin of KIRC. Yang et al20 demonstrated that the abilities of migration and invasion of the tumor cell were suppressed by silencing the expression of ANXA2, whereas tumor cell proliferation was not affected. In our study, the expression of ANXA2 in KIRC tissues was higher than that in normal tissues. We also demonstrated that high ANXA2 expression was significantly correlated with poor OS in the patients with KIRC. However, its expression wasn’t correlated with tumor stage.
Bianchi et al33 cultured primary cell from human renal cell carcinoma and observed two spliced isoforms of ANXA3. However, one spliced isoform of ANXA3 down-regulated in KIRC and the other up-regulated. The total ANXA3 protein down-regulated in KIRC cultures based on microarray analysis. In our report, we demonstrated that the expressions of ANXA3 were not significantly different between tumor and normal tissue, which seemed inconsistent with the Bianchi et al. But we found a high ANXA3 expression was significantly correlated with favorable OS in the patients with KIRC.
A data-independent acquisition-mass spectrometry proteomic approach demonstrated ANXA4 at the expression levels is higher in KIRC than normal tissue34. In our research, we proved for the first time that mRNA expression of ANXA4 was higher in KIRC tissues than in normal tissues, but this expression did not correlate with tumor progression stage. Meanwhile, low expression of ANXA4 was remarkably associated with poor OS in KIRC patients. This study seems that ANXA4 acts as a tumor suppressor gene.
ANXA5 was upregulated in KIRC, and high expression was associated with the higher clinical stage and histological grade19. We found the similar result in our study, that is, the expression of ANXA5 in KIRC tissues was higher than that in normal tissues. And a higher ANXA5 expression was significantly related with poor OS in the patients with KIRC.
ANXA6 is found highly expressed in a variety of tumors, such as acute myeloid leukemia35, pancreatic cancer36, and breast carcinoma37. However, its expression and prognostic role in KIRC have not been reported. In the present study, we confirmed that ANXA6 expression was higher in KIRC tissues than in normal tissues, but this expression did not relate to the stage of the tumor. A higher ANXA6 expression was significantly correlated with poor RFS in the patients with KIRC. Moreover, ANXA6 displayed the highest incidence rate of genetic variations among the super family, which might relate to kidney tumor progression.
The ANXA7-GTPase is considered as a tumor suppressor frequently inactivated by genomic alterations at 10q21 in a variety of human malignancies, including KIRC38. In this report, we demonstrated that the expression of ANXA7 in KIRC tissues was higher than that in normal tissues in Jones’s dataset24, but we also got opposite result from the GEPIA dataset. It was discovered that high-stage KIRC exhibited a significantly reduced ANAX7 expression. Moreover, the decreased ANXA7 mRNA levels were significantly associated with the lower OS that conformed to its role of a tumor suppressor.
ANXA8 is highly expressed in patients with several malignancies, such as ovarian cancer39 and oral squamous cell carcinoma40. Harumi et al41 found that co-transfection with an expression vector for ANXA8 and a reporter gene vector containing the HIF-1α promoter enhanced the activity of the HIF-1α promoter. And it might play a role in calcium fluctuation-mediated HIF-1α transcriptional activation in pancreatic cancer. However, ANXA8’s expression and prognosis role in KIRC have not been reported. In this report, we found that the expression of ANXA8 in KIRC tissues was higher than that in normal tissues, and the high-stage KIRC exhibited a significantly increased ANAX8 expression. The increased ANXA8 mRNA was significantly associated with the poor OS.
ANXA9 and ANXA11’s expression and prognosis role in KIRC have not been reported. Yu et al42 demonstrated ANXA9 promoted invasion and metastasis of colorectal cancer and predicted poor prognosis. ANXA9 showed high expression in head and neck squamous cell carcinomas and associated to the tumor differentiation grade. Hua et al43 found ANXA11 participated in the gastric cancer proliferation, migration, and invasion via the AKT/GSK-3β pathway. But in our report, we demonstrated that the expression of ANXA9 and ANXA11 in KIRC tissues were lower than that in normal tissues, and the expression did not correlate with tumor stage. The decreased ANXA9 and ANXA11 mRNA levels were significantly associated with the poor OS.
It has been proved that abnormal expression of ANXA10 is playing a key role in the generation, progress and prognosis of tumor44–46, although its functional role remains to be clarified and has not been reported in KIRC. The decreased expression of ANXA10 probably participates in malignant progression and poor prognosis47. Overexpression of ANXA10 could promote apoptosis of hepatocellular carcinoma cell48. However, the results of the present study confirmed that high expression of ANXA10 was significantly associated with the poor OS. And the expression of ANXA10 did not associated with clinical stage.
ANXA13 is the latest ANXAs member to be identified. There are limited studies available that focus on ANXA13 in cancer. ANXA13 ramps up cell growth and invasion. It also portended lymph node metastasis and poor prognosis in human colorectal cancer patients49. ANXA13 was identified as a regulator of chemotherapy resistance because ectopic overexpression of ANXA13 could increase the sensitivity of malignant breast cancer cells to Rapamycin50. In the present study, the expression level of ANXA13 was higher in KIRC tissues than in kidney tissues, and the high-stage KIRC exhibited a significantly decreased ANAX13 expression. Moreover, the decreased ANXA13 mRNA level was significantly associated with the poor OS.
Cancer cells carry different mutations which leads to wide varieties of clinical manifestation. Many gene show variations in copy number alterations and many may be associated with recurrence and death51. In present study, we found gene alteration in 9.32% of Annexin family in the database, including an amplification rate of 7.77 %, and a mutation rate of 1.44 %. The incidence rate of genetic variations in the ANXA6 gene was up to 7.0 %, whereas ANXA3, ANXA4 and ANXA10 had higher probabilities of mutation events. However, our finding shown the KIRC has relatively low alteration rate in ANXAs compared with other cancers39,52−54.
We adopted GeneMANIA database to construct a gene-gene interaction network which clarified the mechanisms of function of ANXAs in kidney cancer. The results showed that 20 genes, including STXBP2, RACK1, S100A10, NDRG1 and HARS, were enriched in this network based on their functions associated with physical interactions, co-expression, co-localization, pathway and genetic interaction. It has been demonstrated that RACK1 could regulate the ANXA2 phosphorylation to make it be involved in the invasion and metastasis of drug-resistant carcinoma cells.55 NDRG1, like ANXAs involving in plasma membrane repair, has been recognized as a suppressor of carcinoma by decreasing EMT-associated protein expression56. Aberrant expression of these interacting genes is related to the tumorigenesis and progression of tumors, but these interactions with ANXAs in kidney cancer are intriguing, and still need substantial experimental confirmation. It has been demonstrated that S100A10, located in the plasma membrane, could unite with ANXA2 to form a heterotetramer which composed of two subunits of S100A10 and ANXA2. The heterotetramer could activate the plasminogen activation pathway played a key role in cellular repair and further promote degradation of the extracellular matrix to increase the invasion capability of carcinoma cells57.