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 PrP -Oct4 axis. In specimens from patients with colorectal cancer, the expressions of cellular prion protein (PrP ) 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 PrP . 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 PrP 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, PrP maintains cancer stemness during tumor progression. Therefore, targeting the PrP -Oct4 axis may prove instrumental in colorectal cancer therapy.

The protein kinase, membrane‑associated 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. PKMYT1‑depleted CRC cells were analyzed to determine proliferation, migration, invasion and colony forming ability. In addition, 179 patient‑derived samples were used to find the correlation of the expression of PKMYT1 with the prognosis of CRC patients. By siRNA‑mediated 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 patient‑derived 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.

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.

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.

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.