High expression of LY6E is an independent prognostic factor of colorectal cancer patients.

Colorectal cancer (CRC) is common cancer worldwide, and the 5­year relative survival rate of CRC patients with distant metastasis is as low as 14%. Therefore, identifying markers of CRC is important for the early detection of CRC and applying appropriate treatment strategies. The lymphocyte antigen 6 family (LY6 family) is closely related to the behavior of various cancer types. Among the LY6 family, the lymphocyte antigen 6 complex, locus E (LY6E), which is specifically highly expressed in CRC. Hence, the effects of LY6E on cell function in CRC and its role in CRC recurrence and metastasis were investigated. Reverse transcription­quantitative PCR, western blotting and in vitro functional studies were carried out using four CRC cell lines. Immunohistochemical analysis of 110 CRC tissues was performed to explore the biological functions and expression patterns of LY6E in CRC. LY6E was overexpressed CRC tissues compared with that in adjacent normal tissues. High expression of LY6E in CRC tissues was an independent prognostic factor of worse overall survival (P=0.048). Knockdown of LY6E using small interfering RNA inhibited CRC cell proliferation, migration, invasion, and soft agar colony formation, indicating some of its effects on CRC carcinogenic functions. High expression of LY6E may have oncogenic functions in CRC and be useful as a valuable prognostic marker and potential therapeutic target for CRC.

Expression of Spermine Oxidase Is Associated with Colorectal Carcinogenesis and Prognosis of Patients.

Uncovering tumor markers of colorectal cancer is important for the early detection and prognosis of the patients. Spermine oxidase (SMOX) is upregulated in various cancers. The present study aims to explore the biologic function and expression patterns of SMOX in colorectal cancer (CRC), the third most common type of cancer worldwide. We used quantitative real-time PCR, Western blot, and in vitro functional studies in four CRC cell lines knocked down by SMOX siRNA and immunohistochemistry in 350 cases of CRC tissues. The results showed that SMOX was overexpressed in CRC cell lines and clinical samples. SMOX overexpression in tumor tissues was an independent prognostic factor, worsening overall survival (p = 0.001). The knock-down of SMOX inhibited CRC cell proliferation, invasion, and soft agar colony formation, uncovering its carcinogenic functions. This study indicated that SMOX overexpression could be an important oncogene in CRC and might serve as a valuable prognostic marker and potential therapeutic target for CRC.

Prognostic impact of GPR56 in patients with colorectal cancer.

G protein-coupled receptor 56 (GPR56) belongs to the adhesion G protein-coupled receptor subfamily, which plays a role in cell progression and survival. The aim of this study was to investigate the role of the GPR56 gene in a cell line study and the impact of its protein expression on the prognosis of colorectal cancer (CRC) patients. The effect of GPR56 on tumor cell proliferation (WST-1 assay), invasion (Transwell assay), migration (Transwell assay, wound healing assay), and colony-forming ability (semisolid agar colony-forming assay) was explored. The expression levels of GPR56 in tissue samples of 109 CRC patients were evaluated by immunohistochemistry. The prognostic value of GRP56 was analyzed using univariate and multivariate analyses. The downregulation of GPR56 in the CRC cell line reduced cell proliferation as compared with that in a control sample (48 h; p=0.042, 72 h; p=0.001). Downregulation of the GPR56 expression reduced cell invasion and migration abilities and inhibited colony-forming abilities (p<0.005). The 5-year overall survival rate was worse in the high-expression group as compared with that in the low-expression group (51.6% vs. 74.4%, p=0.008). High GPR56 expression was a significant prognostic factor for overall survival of CRC patients in the univariate (p=0.001) and multivariate (p<0.001) analyses. The expression level of GPR56 plays an important role in tumor progression in CRC, and it may serve as a prognostic indicator in CRC patients.

Prognostic Relevance of HJURP Expression in Patients with Surgically Resected Colorectal Cancer.

HJURP is a key factor for CENP-A deposition and maintenance in centromeres. The role of mis-regulation of histone chaperones in cancer initiation and progression has been studied. However, its role in colorectal cancer is still unclear. In this study, we aimed to evaluate the expression of HJURP in 162 colorectal cancer tissue. To investigate the function of HJURP in the colorectal cancer cell, we suppressed HJURP expression by siRNA and confirmed proliferation, migration, invasion, and anchorage independent of colony forming ability. The association between HJURP expression levels and clinicopathological factors was evaluated in 162 CRC tissues using immunohistochemistry. The overall survival rate in patients of HJURP high expression was higher than those in HJURP low expression in CRC. Suppressing HJURP expression decreased cellular proliferation, invasion, and migration in four CRC cell lines: HT29, HCT116, SW480, SW620 in vitro study. Our findings revealed that the knockdown of HJURP suppressed the proliferation, migration, invasion, and tumorigenicity in CRC cells. Due to its strong association with CRC, HJURP could be a potential prognostic biomarker and a novel target for drug discovery.

Downregulation of miR-9 correlates with poor prognosis in colorectal cancer.

INTRODUCTION: microRNAs (miRNAs) are frequently dysregulated in many human cancers including colorectal cancer (CRC) and are useful candidate biomarkers in liquid biopsy of cancer for their stability in the blood. METHODS: We compared the expression of microRNA-9 (miR-9) in tissues (n = 357) and sera (n = 109) of CRC patients to determine whether miR-9 in serum reflects that in the cancer tissue in parallel. Also, we examined the miR-9 role in CRC by in vitro functional studies in four CRC cell lines. RESULTS: On multivariate analysis of colorectal cancer tissues and sera, miR-9 low expressions were significantly associated pN stage (tissues; p < 0.01, serum; p = 0.013), and clinical stage (tissues; p < 0.01, serum; p = 0.031). Moreover, patients with low miR-9 expression had shorter survival than those with high miR-9 expression (log-rank test, tissue; p = 0.021, serum; p = 0.011). miR-9 level in serum reflects that in the tumor. The CRC cells with low miR-9 expression was significantly increased cell proliferation, migration, invasion and colony formation than cells with high miR-9 expression. CONCLUSION: Serum miR-9 is an useful early detection marker in liquid biopsy of CRC and overexpression of miR-9 in CRC may be a novel prognostic marker as well.

Capicua suppresses colorectal cancer progression via repression of ETV4 expression.

BACKGROUND: Although major driver gene mutations have been identified, the complex molecular heterogeneity of colorectal cancer (CRC) remains unclear. Capicua (CIC) functions as a tumor suppressor in various types of cancers; however, its role in CRC progression has not been examined. METHODS: Databases for gene expression profile in CRC patient samples were used to evaluate the association of the levels of CIC and Polyoma enhancer activator 3 (PEA3) group genes (ETS translocation variant 1 (ETV1), ETV4, and ETV5), the best-characterized CIC targets in terms of CIC functions, with clinicopathological features of CRC. CIC and ETV4 protein levels were also examined in CRC patient tissue samples. Gain- and loss-of function experiments in cell lines and mouse xenograft models were performed to investigate regulatory functions of CIC and ETV4 in CRC cell growth and invasion. qRT-PCR and western blot analyses were performed to verify the CIC regulation of ETV4 expression in CRC cells. Rescue experiments were conducted using siRNA against ETV4 and CIC-deficient CRC cell lines. RESULTS: CIC expression was decreased in the tissue samples of CRC patients. Cell invasion, migration, and proliferation were enhanced in CIC-deficient CRC cells and suppressed in CIC-overexpressing cells. Among PEA3 group genes, ETV4 levels were most dramatically upregulated and inversely correlated with the CIC levels in CRC patient samples. Furthermore, derepression of ETV4 was more prominent in CIC-deficient CRC cells, when compared with that observed for ETV1 and ETV5. The enhanced cell proliferative and invasive capabilities in CIC-deficient CRC cells were completely recovered by knockdown of ETV4. CONCLUSION: Collectively, the CIC-ETV4 axis is not only a key module that controls CRC progression but also a novel therapeutic and/or diagnostic target for CRC.

Defensin alpha 6 (DEFA6) is a prognostic marker in colorectal cancer.

Defensin alpha 6 (DEFA6) is a member of the alpha defensin family of microbicidal and cytotoxic peptides that defend against bacteria and viruses. Here, we provide a novel function of DEFA6 in tumorigenesis of colorectal cancer (CRC) in vitro and in vivo. Specifically, DEFA6 is highly expressed in both CRC cancer cell lines as well as patient-derived samples at the level of RNA and protein. By shRNA-mediated loss of function of DEFA6, we found that proliferation, migration, invasion, colony forming ability of CRC cell lines were impaired in the absence of DEFA6 in vitro. Furthermore, DEFA6-deficient cancer cells exhibited significantly reduced growth rates compared to control cells in vivo. More importantly, by analyzing 352 patient-derived samples, we revealed that DEFA6 is associated with overall survival rate of CRC patients and thus an independent prognostic marker for CRC. These results suggest that DEFA6 plays an essential oncogenic role in CRC and serves a good therapeutic target for the disease.

Melatonin and 5-fluorouracil co-suppress colon cancer stem cells by regulating cellular prion protein-Oct4 axis.

Melatonin suppresses tumor development. However, the exact relationship between melatonin and cancer stem cells (CSCs) is poorly understood. This study found that melatonin inhibits colon CSCs by regulating the PrPC -Oct4 axis. In specimens from patients with colorectal cancer, the expressions of cellular prion protein (PrPC ) and Oct4 were significantly correlated with metastasis and tumor stages. Co-treatment with 5-fluorouracil (5-FU) and melatonin inhibited the stem cell markers Oct4, Nanog, Sox2, and ALDH1A1 by downregulating PrPC . In this way, tumor growth, proliferation, and tumor-mediated angiogenesis were suppressed. In colorectal CSCs, PRNP overexpression protects Oct4 against inhibition by 5-FU and melatonin. In contrast, Nanog, Sox2, and ALDH1A1 have no such protection. These results indicate that PrPC directly regulates Oct4, whereas it indirectly regulates Nanog, Sox2, and ALDH1A1. Taken together, our findings suggest that co-treatment with anticancer drug and melatonin is a potential therapy for colorectal cancer. Furthermore, PrPC maintains cancer stemness during tumor progression. Therefore, targeting the PrPC -Oct4 axis may prove instrumental in colorectal cancer therapy.

Protein kinase, membrane­associated tyrosine/threonine 1 is associated with the progression of colorectal cancer.

The protein kinase, membrane­associated tyrosine/threonine 1 (PKMYT1) is known to inhibit precocious entry into mitosis by phosphorylating CDK1 at Thr14 and Tyr15 residues. However, the functional importance of PKMYT1 in colorectal cancer (CRC) remains unknown. Thus, it is important to elucidate whether PKYMT1 is indispensable in the tumorigenesis of CRC. To investigate the functional importance of PKMYT1 in CRC tumorigenesis, PKMYT1 was knocked down in CRC cell lines such as SW480, SW620, HCT116 and HT29 by siRNA. PKMYT1­depleted CRC cells were analyzed to determine proliferation, migration, invasion and colony forming ability. In addition, 179 patient­derived samples were used to find the correlation of the expression of PKMYT1 with the prognosis of CRC patients. By siRNA­mediated loss of function of PKMYT1, we observed that proliferation, migration, invasion and colony forming ability of CRC cell lines were significantly impaired in the absence of PKMYT1 in vitro. Furthermore, by analyzing patient­derived samples, we revealed the association of PKMYT1 with the overall survival rate of CRC patients. These results indicated that PKMYT1 plays an essential oncogenic role in CRC and could serve as a good therapeutic target for the treatment of CRC.

Karyopherin α-2 is a reliable marker for identification of patients with high-risk stage II colorectal cancer.

PURPOSE: Adjuvant chemotherapy (AC) is frequently considered in patients with high-risk stage II colorectal cancer (CRC). Among patients with stage II CRC who do not receive AC because they are not considered to be at high risk, 20-25% will develop recurrence and die from the disease. Elevated levels of KPNA2 have been observed in various cancers, and overexpression of KPNA2 is related to CRC progression. METHODS: We examined the expression of KPNA2 using 293 CRC tissues, including 118 with stage II CRC, and investigated the applicability of KPNA2 as a biomarker to predict high-risk stage II CRC. Moreover, we further investigated the role of KPNA2 as an oncogene in CRC carcinogenesis using in vitro functional studies. RESULTS: High KPNA2 expression was associated with vascular (p = 0.027) and lymphatic invasion (p = 0.009) in patients with stage II CRC. On multivariate analysis, high KPNA2 expression (HR 3.174, 95% CI 2.060-4.889; p < 0.001) was independently associated with survival in patients with CRC. The overall survival rate in patients with high KPNA2 expression was higher than that in patients with low KPNA2 expression in CRC (p < 0.001), even in patients with stage II CRC (p = 0.001). Additionally, KPNA2 was associated with tumorigenesis and cancer progression in CRC cells; high KPNA2 expression was associated with increased cell proliferation (p < 0.05), migration (p = 0.03), invasion (p = 0.001), and semisolid agar colony formation (p < 0.001). CONCLUSION: KPNA2 expression is useful for identification of patients with high-risk stage II CRC who could benefit from AC and that KPNA2 may also be a promising therapeutic target.