High kinesin family member 11 expression predicts poor prognosis in patients with clear cell renal cell carcinoma

Abstract

Aims: Kinesin family member 11 (Kif11) is a member of the kinesin family motor proteins, which is associated with spindle formation and tumour genesis. In this study, we investigated the relationship between Kif11 expression and clear cell renal cell carcinoma (CCRCC) development.

Methods: The relationship between Kif11 expression and CCRCC development was analysed by quantitative real-time (qRT)-PCR analyses, and tissue immunohistochemistry. The prognostic significance of Kif11 expression was explored by univariable and multivariable survival analyses of 143 included patients. Furthermore, SB743921 was used as a specific Kif11 inhibitor to treat 786-O cells with the epithelial to mesenchymal transition (EMT) process analysed by qRT-PCR, and cell survival rates analysed with Annexin V-FITC/PI staining followed by flow cytometric analyses. Disease-free survival curves of Kif11 with different cancers and the relationships between Kif11 and the von Hippel-Lindau disease tumour suppressor gene (VHL), and proliferating cell nuclear antigen (PCNA) in kidney cancer were further analysed using the GEPIA database.

Results: The levels of Kif11 mRNA were significantly higher in CCRCC tissues compared with corresponding non-cancerous tissues. The results of immunohistochemistry demonstrated that the expression of Kif11 protein was significantly associated with clinicopathologial parameters, including nuclear grade and TNM stage. The Kaplan-Meier survival curve indicated that high Kif11 expression, nuclear grade and TNM stage were independent factors to predict poor prognosis in patients with CCRCC. In addition, inhibition of Kif11 expression by SB743921 suppressed cell proliferation, migration and the EMT process with increased apoptosis rate.

Conclusions: These results combined with bioinformation analyses suggest that high Kif11 expression was associated with unfavourable prognosis in CCRCC and could be used as a potential prognostic marker in the clinical diagnosis of CCRCC.

Keywords: Clear cell renal cell carcinoma; EMT; Kif11; prognosis.

Figure 1

Quantitative real-time PCR analyses were used to detect the kinesin family member 11 (Kif11) mRNA expression levels in clear cell renal cell carcinoma (CCRCC) tissues and the corresponding adjacent tissues. The Kif11 mRNA median level in CCRCC tissues is 0.7799 (IQR 0.6227–1.2454), compared with the median level in the adjacent tissues which is 0.4111 (IQR 0.3066–0.6487) (Z=−4.391, p<0.001, with Wilcoxon signed-rank non-parametric test).

Figure 2

Representative images of the kinesin family member 11 (Kif11) protein and proliferating cell nuclear antigen (PCNA) location and expression in clear cell renal cell carcinoma (CCRCC) tissues. (A) No immunohistochemistry (IHC) staining of Kif11 in the cytoplasm of normal kidney cells. (B) High IHC staining of Kif11 in the cytoplasm of normal kidney cells. (C) Low IHC staining of Kif11 in the cytoplasm of CCRCC cells. (D) Moderate IHC staining of Kif11 in the cytoplasm of CCRCC cells. (E) High IHC staining of Kif11 in the cytoplasm of CCRCC cells. (F) Low IHC staining of PCNA in the nucleus of CCRCC cells. (G) Moderate IHC staining of PCNA in the nucleus of CCRCC cells. (H) High IHC staining of PCNA in the nucleus of CCRCC cells. Bar=50 µm.

Figure 3

Survival analyses of patients with clear cell renal cell carcinoma (CCRCC) using the Kaplan-Meier test. (A) Overall survival rate in patients with CCRCC and high expression levels of kinesin family member 11 (Kif11) (green line) was statistically lower than that in patients with CCRCC and low or no Kif11 expression (blue line). (B) Overall survival rate in patients with CCRCC and nuclear grade G3–4 was statistically higher than that in patients with CCRCC and nuclear grade G1 and G2. (C) Overall survival rate in patients with CCRCC and TNM stage Ⅲ+Ⅳ was statistically higher than that in patients with CCRCC and TNM stageⅠ and Ⅱ.

Figure 4

Inhibition of kinesin family member 11 (Kif11) in 786-O cells by SB743921 treatments. (A) Early apoptosis rate of 786-O cells by SB743921 treatments by FACS. (B) Effects of SB743921 on 786-O cell growth over 72 hours. Different letters indicate significant difference (p<0.05). (C) Representative micrographs of the motility of 786-O cells in the wound healing assay at 0 and 24 hours. PBS, phosphate-buffered saline.

Figure 5

Expression of epithelial to mesenchymal transition (EMT) related genes and kinesin family member 11 (Kif11) mRNA in 786-O cells with SB743921 treatments. Different letters in each column indicate significant difference (p<0.05). PBS, phosphate-buffered saline.

Figure 6

High expression of kinesin family member 11 (Kif11) was correlated with poorer prognosis in different cancers. Overall survival rates in patients with ACC, BLCA, KICH, KIRP, SARC, LIHC, LGG, PAAD and UVM with high expression levels of Kif11 protein (red line) were statistically lower than those in patients with low and no Kif11 expression (blue line). ACC, adrenocortical carcinoma; BLCA, bladder urothelial carcinoma; LGG, brain lower grade glioma; KICH, kidney chromophobe; KIRP, kidney renal papillary cell carcinoma; LIHC, liver hepatocellular carcinoma;PAAD, pancreatic adenocarcinoma; SARC, sarcoma; TPM, transcripts per kilobase of exonmodel per million mapped reads; UVM. uveal melanoma.

Figure 7

Relationship between kinesin family member 11 (Kif11), proliferating cell nuclear antigen (PCNA) and the von Hippel-Lindau disease tumour suppressor gene (VHL) in kidney renal clear cell carcinoma tissues. TPM, transcripts per kilobase of exonmodel per million mapped reads.