GENES, CHROMOSOMES & CANCER 53:358–365 (2014)
Low Expression of MicroRNA-126 is Associated with Poor Prognosis in Colorectal Cancer Yaling Liu,1† Yu Zhou,2† Xiao Feng,2 Pengchun Yang,2 Jingfang Yang,2 Ping An,1 Hao Wang,2 Shicai Ye,2 Caiyuan Yu,2 Yanting He,2 and Hesheng Luo1* 1
Department of Gastroenterology,Renmin Hospital of Wuhan University,Wuhan,Hubei province,China Department of Gastroenterology, the Aff|liated Hospital of Guangdong Medical College, Zhanjiang,Guangdong province,China
2
MicroRNA-126 (miR-126) has been reported to be a tumor suppressor that targets CXCR4 in colorectal cancer (CRC) cells. This study investigated whether miR-126 has any prognostic impact in patients with CRC. MiR-126 and CXCR4 mRNA expression in 92 pairs of CRC and adjacent nontumorous tissues was examined using quantitative real-time PCR, and CXCR4 protein expression was assessed by immunohistochemistry (IHC) and Western blotting. The correlation between miR-126 and CXCR4 protein expression and clinicopathological features and overall survival rate was determined. MiR-126 was downregulated in CRC tissues that expressed high levels of CXCR4 mRNA. IHC and Western blotting detected high expression of CXCR4 protein in CRC tissues. An inverse correlation was observed between miR-126 and CXCR4 protein expression in CRC tissues. Moreover, low miR-126 and high CXCR4 protein expression was associated with distant metastasis, clinical TNM stage, and poor survival. Multivariate analysis indicated that miR-126 was an independent prognostic factor for overall survival, suggesting its clinical significance as a prognostic predictor in CRC C 2014 Wiley Periodicals, Inc. V patients.
INTRODUCTION
Colorectal cancer (CRC) is a major cause of mortality and accounts for 9% of all cancer deaths in the Western world (Siegel et al., 2013), with high possibilities of recurrence and metastasis. The prognosis for CRC patients has shown little improvement despite advances in treatment approaches over the last decades. Consequently, there is an ongoing effort to identify novel and effective targets to improve therapeutic efficacy and clinical outcome. MicroRNAs (miRNAs) are small RNAs that can regulate gene expression via complementary base pairing with the 30 untranslated region (30 -UTR) of target mRNAs, resulting in translational repression or mRNA degradation (Bartel, 2004). MiRNAs are known to mediate diverse biological processes, such as cell proliferation, differentiation, and apoptosis (Bartel, 2004). Many studies have reported specific aberrant miRNAs expression profiles of various cancer types (Calin and Croce, 2006; Catto et al., 2011), and recent reports indicate that miRNAs may function as tumor suppressors as well as oncogenes (Esquela-Kerscher and Slack, 2006; Babashah and Soleimani, 2011). Moreover, accumulating evidence suggests that miRNAs are potential biomarkers of diagnosis, treatment, and outcomes, which are highly tissueC 2014 Wiley Periodicals, Inc. V
specific for cancer patients (Takamizawa et al., 2004; Cho, 2007; Nair et al., 2012). MiR-126 is frequently downregulated in a variety of malignancies (Tavazoie et al., 2008; Wang et al., 2008; Walter et al., 2013) and acts as a potential tumor suppressor. Moreover, low expression of miR-126 has been correlated with poor prognosis in patients with breast cancer, adult Tcell leukemia, and malignant mesothelioma (Tavazoie et al., 2008; Ishihara et al., 2012; Tomasetti et al., 2012). Likewise, miR-126 is downregulated in CRC and plays important roles in cell proliferation, invasion, and metastasis by regulating several targets (Guo et al., 2008; Li et al., 2013b). One target of miR-126 is the CXCchemokine receptor-4 (CXCR4) (Li et al., 2013b), a seven-transmembrane G-protein-coupled receptor of stromal cell-derived factor (SDF-1). Upregulation of CXCR4 expression has been observed in various cancers, including CRC, and has been *Correspondence to: Hesheng Luo, Department of Gastroenterology, Renmin Hospital of Wuhan University, Number 238, Jiefang Road, Wuhan 430060, Hubei Province, China. E-mail: [email protected] † Yaling Liu and Yu Zhou contributed equally to this manuscript. Received 12 November 2013; Accepted 7 January 2014 DOI 10.1002/gcc.22146 Published online 29 January 2014 in Wiley Online Library (wileyonlinelibrary.com).
MIR-126 IS ASSOCIATED WITH PROGNOSIS OF CRC
TABLE 1. Demographic and Pathological Characteristics of 92 Patients with CRC Characteristics Male Age (years) Means 6 SD Range Tumor location Colon Rectum Tumor size
Low Expression of MicroRNA-126 is Associated with Poor Prognosis in Colorectal Cancer Yaling Liu,1† Yu Zhou,2† Xiao Feng,2 Pengchun Yang,2 Jingfang Yang,2 Ping An,1 Hao Wang,2 Shicai Ye,2 Caiyuan Yu,2 Yanting He,2 and Hesheng Luo1* 1
Department of Gastroenterology,Renmin Hospital of Wuhan University,Wuhan,Hubei province,China Department of Gastroenterology, the Aff|liated Hospital of Guangdong Medical College, Zhanjiang,Guangdong province,China
2
MicroRNA-126 (miR-126) has been reported to be a tumor suppressor that targets CXCR4 in colorectal cancer (CRC) cells. This study investigated whether miR-126 has any prognostic impact in patients with CRC. MiR-126 and CXCR4 mRNA expression in 92 pairs of CRC and adjacent nontumorous tissues was examined using quantitative real-time PCR, and CXCR4 protein expression was assessed by immunohistochemistry (IHC) and Western blotting. The correlation between miR-126 and CXCR4 protein expression and clinicopathological features and overall survival rate was determined. MiR-126 was downregulated in CRC tissues that expressed high levels of CXCR4 mRNA. IHC and Western blotting detected high expression of CXCR4 protein in CRC tissues. An inverse correlation was observed between miR-126 and CXCR4 protein expression in CRC tissues. Moreover, low miR-126 and high CXCR4 protein expression was associated with distant metastasis, clinical TNM stage, and poor survival. Multivariate analysis indicated that miR-126 was an independent prognostic factor for overall survival, suggesting its clinical significance as a prognostic predictor in CRC C 2014 Wiley Periodicals, Inc. V patients.
INTRODUCTION
Colorectal cancer (CRC) is a major cause of mortality and accounts for 9% of all cancer deaths in the Western world (Siegel et al., 2013), with high possibilities of recurrence and metastasis. The prognosis for CRC patients has shown little improvement despite advances in treatment approaches over the last decades. Consequently, there is an ongoing effort to identify novel and effective targets to improve therapeutic efficacy and clinical outcome. MicroRNAs (miRNAs) are small RNAs that can regulate gene expression via complementary base pairing with the 30 untranslated region (30 -UTR) of target mRNAs, resulting in translational repression or mRNA degradation (Bartel, 2004). MiRNAs are known to mediate diverse biological processes, such as cell proliferation, differentiation, and apoptosis (Bartel, 2004). Many studies have reported specific aberrant miRNAs expression profiles of various cancer types (Calin and Croce, 2006; Catto et al., 2011), and recent reports indicate that miRNAs may function as tumor suppressors as well as oncogenes (Esquela-Kerscher and Slack, 2006; Babashah and Soleimani, 2011). Moreover, accumulating evidence suggests that miRNAs are potential biomarkers of diagnosis, treatment, and outcomes, which are highly tissueC 2014 Wiley Periodicals, Inc. V
specific for cancer patients (Takamizawa et al., 2004; Cho, 2007; Nair et al., 2012). MiR-126 is frequently downregulated in a variety of malignancies (Tavazoie et al., 2008; Wang et al., 2008; Walter et al., 2013) and acts as a potential tumor suppressor. Moreover, low expression of miR-126 has been correlated with poor prognosis in patients with breast cancer, adult Tcell leukemia, and malignant mesothelioma (Tavazoie et al., 2008; Ishihara et al., 2012; Tomasetti et al., 2012). Likewise, miR-126 is downregulated in CRC and plays important roles in cell proliferation, invasion, and metastasis by regulating several targets (Guo et al., 2008; Li et al., 2013b). One target of miR-126 is the CXCchemokine receptor-4 (CXCR4) (Li et al., 2013b), a seven-transmembrane G-protein-coupled receptor of stromal cell-derived factor (SDF-1). Upregulation of CXCR4 expression has been observed in various cancers, including CRC, and has been *Correspondence to: Hesheng Luo, Department of Gastroenterology, Renmin Hospital of Wuhan University, Number 238, Jiefang Road, Wuhan 430060, Hubei Province, China. E-mail: [email protected] † Yaling Liu and Yu Zhou contributed equally to this manuscript. Received 12 November 2013; Accepted 7 January 2014 DOI 10.1002/gcc.22146 Published online 29 January 2014 in Wiley Online Library (wileyonlinelibrary.com).
MIR-126 IS ASSOCIATED WITH PROGNOSIS OF CRC
TABLE 1. Demographic and Pathological Characteristics of 92 Patients with CRC Characteristics Male Age (years) Means 6 SD Range Tumor location Colon Rectum Tumor size
