Evaluation of KIF23 variant 1 expression and relevance as a novel prognostic factor in patients with hepatocellular carcinoma
BMC CANCER
Authors: Sun, Xiaotong; Jin, Zhongtian; Song, Xiao; Wang, Jingjing; Li, Yan; Qian, Xiaoping; Zhang, Yu; Yin, Yanhui
Abstract
Background: KIF23 (kinesin family member 23) is a kinesin-like motor protein and plays an important role in cytokinesis. In search for genes associated with hepatocellular carcinoma (HCC) by cDNA microarray, we found that KIF23 was upregulated in HCC tissues. At present, much less is known about its expression and functions in tumor cells. In this work, we aimed to investigate the expression of KIF23 in HCC and the correlation between its expression and clinical features. Methods: Total RNA was extracted from 16 HCC and paired adjacent non-cancerous tissues. The expressions of the two KIF23 splice variants (KIF23 V1 and KIF23 V2) in normal and HCC tissues were determined by reverse transcriptase polymerase chain reaction (RT-PCR). Polyclonal antibody specific to KIF23 V1 was prepared, and the specificity of the antibody was confirmed by siRNA knockdown and Western blotting experiments. KIF23 protein expression in HCC was examined by immunohistochemistry staining with anti-KIF23 V1 or anti-KIF23 (commercially available for recognizing both KIF23 V1 and V2) antibodies, respectively. Univariate and Multivariate Cox regression analyses were used to determine the correlation between KIF23 protein expression and overall survival of HCC patients. Results: The two splicing variants of KIF23 mRNA were not detected in normal liver tissue by RT-PCR, but they were aberrantly expressed in HCC tissues. Immunohistochemistry staining with anti-KIF23 V1 antibody revealed that KIF23 V1 was mainly distributed in the nucleus, whereas the positive staining signals were predominantly in the cytoplasm when using anti-KIF23 antibody, suggesting that KIF23 V2 might localize in the cytoplasm of HCC cells. KIF23 V1 protein was detected in 57.6 % (83/144) HCC patients and the mean H-score was 42, while KIF23 V2 was detected in 94.4 % (135/143) HCC samples and the mean H-score was 68. Follow-up study showed that HCC patients with expression of KIF23 V1 had a longer 5-year survival (p = 0.0052), however, expression of KIF23 V2 protein did not associate with 3- and 5-year survival. Conclusion: In this study we show for the first time that KIF23 V1 and V2 have different localizations in HCC cells. Furthermore, KIF23 V1 protein expression might be a marker of longer overall survival in HCC patients.
KIF15 promotes pancreatic cancer proliferation via the MEK-ERK signalling pathway
BRITISH JOURNAL OF CANCER
Authors: Wang, Jie; Guo, Xingjun; Xie, Chencheng; Jiang, Jianxin
Abstract
Background: Pancreatic cancer is highly malignant and characterised by rapid and uncontrolled growth. While some of the important regulatory networks involved in pancreatic cancer have been determined, the cancer relevant genes have not been fully identified. Methods: We screened genes that may control proliferation in pancreatic cancer in seven pairs of matched pancreatic cancer and normal pancreatic tissue samples. We examined KIF15 expression in pancreatic cancer tissues and the effect of KIF15 on cell proliferation in vitro and in vivo. The mechanisms underlying KIF15 promotion of cell proliferation were investigated. Results: mRNA microarray and functional analysis identified 22 genes that potentially play an important role in the proliferation of pancreatic cancer. High-content siRNA screening evaluated whether silencing these 22 genes affected proliferation of pancreatic cancer. Notably, silencing KIF15 exhibited the most potent inhibition of proliferation compared with the rest of the 22 genes. KIF15 was upregulated in human pancreatic cancer tissues, and higher KIF15 expression levels correlated with shorter patient survival times. Upregulation KIF15 promoted pancreatic cancer growth. KIF15 upregulated cyclin D1, CDK2, and phospho-RB and also promoted G1/S transition in pancreatic cancer cells. KIF15 upregulation activated MEK-ERK signalling by increasing p-MEK and p-ERK levels. MEK-ERK inhibitors successfully inhibited cell cycle progression, and PD98059 blocked KIF15-mediated pancreatic cancer proliferation in vivo and in vitro. Conclusions: This study identified KIF15 as a critical regulator that promotes pancreatic cancer proliferation, broadening our understanding of KIF15 function in tumorigenesis.