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Cuproptosis is a new form of copper-dependent programmed cell death commonly occurring within the body. There is emerging evidence indicating that cuproptosis has a significant regulatory function in the onset and progression of cancer. However, it is still unclear how cuproptosis regulates cancer and whether other genes are involved in the regulation. Using the TCGA-COAD dataset of 512 samples, we found that seven of ten cuproptosis markers showed prognostic value in colorectal cancer (CRC) using Kaplan–Meier survival analysis. Furthermore, 31 prognostic cuproptosis-related genes were identified using weighted gene co-expression network analysis and univariate Cox analysis. Subsequently, we constructed a 7-PCRG signature using least absolute shrinkage and selection operator (LASSO)–Cox regression analysis. The risk score predicting survival in patients with CRC was evaluated. Two risk groups were classified based on their risk scores. The two groups revealed a significant difference in immune cells, such as B and T cells. Furthermore, we identified differences in many immune functions and checkpoints, including CD276 and CD28. In vitro experiments showed that a hub cuproptosis-related gene, TIGD1, could significantly regulate cuproptosis in CRC after exposure to elesclomol. This study validated that cuproptosis was closely related to the progression of CRC. Seven new cuproptosis-related genes were identified, and the function of TIGD1 in cuproptosis was preliminarily understood. Since a certain concentration of copper in CRC cells is important, cuproptosis may provide a new target for cancer therapy. This study may provide novel insights into the treatment of CRC.

Background Circular RNAs (circRNAs) play important roles in cancer progression and metabolism regulation. Serine/glycine metabolism supports the growth of cancer cells by contributing to their anabolic demands and epigenome as well as by regulating their redox state. However, the role of circRNA in the regulation of serine/glycine metabolism has not been well elucidated. Methods Microarray analysis was used to screen differentially expressed novel circRNAs. qRT-PCR and FISH were utilized to analyzed the expression of circMYH9. CCK8, colony formation and FACS were used to analyze proliferation of colorectal cancer (CRC) cells. Xenograft experiments were used to analyze tumor growth in vivo. RNA-sequencing, immunoblot and LC–MS were used to identify the downstream metabolic pathway of circMYH9. ChIRP, Mass Spectrometry, RIP and RNA pulldown were utilized to test the interaction between circMYH9, hnRNPA2B1 and p53 pre-mRNA. ChIP-qPCR was used to analyze the binding sites of HIF-1α. Chemically-induced CRC mice were generated to evaluate the role of circMYH9 in tumorigenesis. Results We identified an intron-derived circRNA, circMYH9, which was significantly upregulated in CRC tissues. A higher circMYH9 level correlated with shorter relapse-free survival and overall survival of CRC patients. CircMYH9 promoted serine/glycine metabolism, the NAD + /NADH ratio, and glutathione recycling and inhibited reactive oxygen species (ROS) in a p53-dependent manner, impacting tumour growth. Mechanistically, circMYH9 destabilized the pre-mRNA of p53 by recruiting hnRNPA2B1 in the nucleus. hnRNPA2B1 bound to N6-methyladenosine sites on the 3' untranslated region of p53 pre-mRNA and maintained its stability. Moreover, a lack of amino acids led to an elevated level of ROS, resulting in increased HIF1α, which promoted circMYH9 expression by binding to the promoter region. Furthermore, in vivo AAV9-mediated transfection of circMYH9 could drive chemically-induced carcinogenesis by suppressing p53 in mice. Conclusions The overexpression of circMYH9 promotes CRC proliferation though modulating serine/glycine metabolism and redox homeostasis in a p53-dependent manner, and targeting circMYH9 and its pathway may be an effective strategy for the treatment of CRC.

Background Currently, whether daily excess iodized salt intake increases the risk of thyroid nodules and even thyroid cancer remains controversial. Our research group aimed to provide a theoretical basis for the clinical guidance of daily iodized salt intake and the prevention of thyroid nodules through a retrospective analysis of the correlation between daily iodized salt intake and the risk of thyroid nodules and thyroid cancer in Hunan, China. Methods This study retrospectively analyzed the data of subjects who underwent a physical examination at the Health Management Center, Third Xiangya Hospital of Central South University, between January 1, 2017, and December 31, 2019. Subjects enrolled in this study underwent thyroid ultrasonography and tests to urine routines and liver and kidney function, and all subjects completed a questionnaire survey. The daily iodized salt intake of the study subjects was estimated based on spot urine methods (Tanaka). A multivariate logistic regression model was used to analyze the relationship between daily iodized salt intake and thyroid nodules and thyroid cancer. Results Among the 51,637 subjects included in this study, the prevalence of thyroid nodules was 40.25%, and the prevalence of thyroid cancer was 0.76%; among all enrolled subjects, only 3.59% had a daily iodized salt intake less than 5 g. In addition, we found that a daily intake of more than 5 g of iodized salt was not only an independent risk factor for the occurrence of thyroid nodules (odds ratio (OR): 2.08, 95% confidence interval (CI): 1.86–2.31, p p = 0.012). A pooled analysis showed a significantly higher risk of thyroid nodules in subjects aged > 60 years with a daily iodized salt intake of more than 5 g compared to subjects aged p 60 years with a daily iodized salt intake of more than 5 g and those aged p = 0.281). The risk of thyroid nodules was not increased in physically active subjects with a daily iodized salt intake of more than 5 g compared to physically inactive subjects with a daily iodized salt intake of no more than 5 g (OR: 1.12, 95% CI: 0.97–1.28, p = 0.111). The same protective effect of physical activity was observed for thyroid cancer in subjects whose daily iodized salt intake exceeded 5 g. The risk of thyroid nodules was reduced for subjects with an education level of postgraduate and above, even when the daily iodized salt intake exceeded 5 g, compared to those with high school education and below and a daily iodized salt intake of no more than 5 g (OR: 0.79, 95% CI: 0.66–0.93, p = 0.005); however, a protective effect of education level on the occurrence of thyroid cancer was not observed. Independent risk factors affecting daily iodized salt intake greater than 5 g included age, triglycerides, family history of tumors, physical activity, and marital status. Conclusions Daily intake of more than 5 g of iodized salt increased the risk of thyroid nodules and thyroid cancer, while increased physical activity and education level reduced the risk of thyroid nodules and thyroid cancer caused by iodized salt intake.

BackgroundIndividual immune-related alternative splicing (AS) events have been found to be significant in immune regulation and cancer prognosis. However, a comprehensive analysis of AS events in cancer cells based on immune-related genes (IRGs) has not been performed, and its clinical value is unknown.MethodsColon cancer cases with AS data were obtained from TCGA, and then, we identified overall survival-related AS events (OS-ASEs) based on IRGs by univariate analyses. Using Lasso regression, multivariate Cox regression, Kaplan–Meier analysis and nomograms, we constructed an AS risk model based on the calculated risk score. Furthermore, associations of the risk score with clinical and immune features were confirmed through the Wilcoxon rank sum test, association analysis, etc. Finally, by qRT–PCR, cell coculture and CCK-8 analyses, we validated the significance of OS-ASEs in colon cancer cell lines and clinical samples.ResultsA total of 3,119 immune-related AS events and 183 OS-ASEs were identified, and 9 OS-ASEs were ultimately used to construct a comprehensive risk model for colon cancer patients. Low-risk patients had better OS and DFS rates than high risk patients. Furthermore, a high risk score corresponded to high numbers of multiple tumour-infiltrating immune cells and high expression of HLA-D region genes and immune checkpoint genes. Notably, we identified for the first time that anti-PD-L1 or anti-CTLA-4 antibodies may decrease the OS of specific colon cancer patients in the low-risk group. Additionally, the in vitro experiment validated that CD46-9652-ES and PSMC5-43011-ES are positively correlated with the infiltration of immune cells and promote the growth of colon cancer cells. CD46-9652-ES can contribute to T cell-mediated tumour cell killing. PSMC5-43011-ES was observed to induce M2 polarization of macrophages.ConclusionsThis study identified and validated immune-related prognostic AS signatures that can be used as a novel AS prognostic model and provide a novel understanding of the relationship between the immune microenvironment and clinical outcomes.

AS (alternative splicing) is a fundamental process by which a gene can generate multiple distinct mRNA transcripts to increase protein diversity. Defects in AS influence the occurrence and development of many diseases, including cancers, and are frequently found to participate in various aspects of cancer biology, such as promoting invasion, metastasis, apoptosis resistance and drug resistance. NcRNAs (noncoding RNAs) are an abundant class of RNAs that do not encode proteins. NcRNAs include miRNAs (microRNAs), lncRNAs (long noncoding RNAs), circRNAs (circular RNAs) and snRNAs (small nuclear RNAs) and have been proven to act as regulatory molecules that mediate cancer processes through AS. NcRNAs can directly or indirectly influence a plethora of molecular targets to regulate cis-acting elements, trans-acting factors, or pre-mRNA transcription at multiple levels, affecting the AS process and generating alternatively spliced isoforms. Consequently, ncRNA-mediated AS outcomes affect multiple cellular signaling pathways that promote or suppress cancer progression. In this review, we summarize the current mechanisms by which ncRNAs regulate AS in cancers and discuss their potential clinical applications as biomarkers and therapeutic targets.

Background Previous studies have shown that the N6-methyladenosine (m6A) modification enhances the binding ability of mRNAs/long noncoding RNAs (lncRNAs) to microRNAs (miRNAs), but the impact of this modification on the competitive endogenous RNA (ceRNA) function of circular RNAs (circRNAs) is unclear. Methods We used a human circRNA microarray to detect the expression profiles of circRNAs in 3 pairs of cancer and paracancerous tissues from patients with colorectal cancer (CRC) and 3 pairs of peripheral blood specimens from patients with CRC and healthy individuals. The circRNAs highly expressed in both peripheral blood and tumour tissues of patients with CRC, including circALG1, were screened. A quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis of an expanded sample size was performed to detect the expression level of circALG1 in peripheral blood and tumour tissues of patients with CRC and determine its correlation with clinicopathological features, and circRNA loop-forming validation and stability assays were then conducted. Transwell assays and a nude mouse cancer metastasis model were used to study the function of circALG1 in CRC and the role of altered m6A modification levels on the regulation of circALG1 function. qRT-PCR, western blot (WB), Transwell, RNA-binding protein immunoprecipitation (RIP), RNA antisense purification (RAP), and dual-luciferase reporter gene assays were performed to analyse the ceRNA mechanism of circALG1 and the effect of the m6A modification of circALG1 on the ceRNA function of this circRNA. Results CircALG1 was highly expressed in both the peripheral blood and tumour tissues of patients with CRC and was closely associated with CRC metastasis. CircALG1 overexpression promoted the migration and invasion of CRC cells, and circALG1 silencing and reduction of the circALG1 m6A modification level inhibited CRC cell migration and invasion. In vivo experiments further confirmed the prometastatic role of circALG1 in CRC. Further mechanistic studies showed that circALG1 upregulated the expression of placental growth factor (PGF) by binding to miR-342-5p and that m6A modification enhanced the binding of circALG1 to miR-342-5p and promoted its ceRNA function. Conclusion M6A modification enhances the binding ability of circALG1 to miR-342-5p to promote the ceRNA function of circALG1, and circALG1 could be a potential therapeutic target in and a prognostic marker for CRC.

Transcription factors are frequently aberrantly reactivated in various cancers, including colorectal cancer (CRC). However, as a transcription factor, the role of GMEB2 in cancer is still unclear, and further studies are needed. Here, we aimed to identify the function and mechanism of GMEB2 in regulating the malignant progression of CRC. GMEB2 was found to be highly expressed in online data analyses. We demonstrated that GMEB2 was markedly upregulated at both the mRNA and protein levels in CRC cells and tissues. GMEB2 knockdown inhibited CRC cell growth in vitro and in vivo. Mechanistically, as a transcription factor, GMEB2 transactivated the ADRM1 promoter to increase its transcription. Rescue experiments showed that ADRM1 downregulation partially reversed the promoting effects of GMEB2 on CRC growth in vitro. Moreover, the GMEB2/ADRM1 axis induced nuclear translocation of NF-κB, thus activating NF-κB signalling. Finally, we further revealed that YTHDF1 recognized and bound to the m6A site on GMEB2 mRNA, which enhanced its stability. Taken together, our findings reveal the crucial role and regulatory mechanism of GMEB2 in CRC for the first time and provide a novel potential therapeutic target for CRC therapy.

Alternative splicing (AS) event is a novel biomarker of tumor tumorigenesis and progression. However, the comprehensive analysis of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) is lacking. Differentially expressed analysis was used to identify the differentially expressed alternative splicing (DEAS) events between HCC or ICC tissues and their normal tissues. The correlation between DEAS events and functional analyses or immune features was evaluated. The cluster analysis based on DEAS can accurately reflect the differences in the immune microenvironment between HCC and ICC. Forty-five immune checkpoints and 23 immune features were considered statistically significant in HCC, while only seven immune checkpoints and one immune feature in ICC. Then, the prognostic value of DEAS events was studied, and two transcripts with different basic cell functions (proliferation, cell cycle, invasion, and migration) were produced by ADHFE1 through alternative splicing. Moreover, four nomograms were established in conjunction with relevant clinicopathological factors. Finally, we found two most significant splicing factors and further showed their protein crystal structure. The joint analysis of the AS events in HCC and ICC revealed novel insights into immune features and clinical prognosis, which might provide positive implications in HCC and ICC treatment.

The RNA binding protein PTBP3 was recently reported to play a critical role in multiple cancers, and the molecular mechanisms involved RNA splicing, 3′ end processing and translation. However, the role of PTBP3 in colorectal cancer (CRC) remains poorly explored. Herein, PTBP3 was upregulated in CRC and associated with a poor prognosis. PTBP3 knockdown in colorectal cancer cell lines restricted CRC proliferative capacities in vitro and in vivo. Mechanistically, PTBP3 regulated the expression of the E3 ubiquitin ligase UBE4A by binding the 3′ UTR of its mRNA, preventing its degradation. UBE4A participated in P53 degradation, and PTBP3 knockdown in colorectal cancer cell lines showed increased P53 expression. UBE4A overexpression rescued PTBP3 knockdown-induced inhibition of CRC cell proliferation and P53 expression. Our results demonstrated that PTBP3 plays an essential role in CRC cell proliferation by stabilizing UBE4A to regulate P53 expression and may serve as a new prognostic biomarker and effective therapeutic target for CRC.

Background Colorectal cancer (CRC) is the most common malignancy worldwide and has become the second leading cause of cancer-related death worldwide. The RNA-binding protein polypyrimidine tract-binding protein 3 (PTBP3) was recently reported to play a critical role in multiple cancers, and its molecular mechanisms involve RNA splicing, 3′ end processing and translation. However, the role of PTBP3 in CRC is unclear. Methods We analyzed the expression levels of PTPB3 using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets and clinical tissues. The effect of PTBP3 on CRC cell proliferation was measured by Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry and tumor xenograft assays. A series of experiments were conducted to reveal the mechanisms by which PTBP3 promotes CRC proliferation. Results We showed that PTBP3 was upregulated in CRC and associated with a poor prognosis. Knockdown of PTBP3 in CRC cell lines restricted CRC proliferative capacities in vitro and in vivo. Mechanistically, we found that PTBP3 regulated the expression of the E3 ubiquitin ligase ubiquitination factor E4A (UBE4A) by binding the 3' untranslated region (UTR) of its mRNA, thereby preventing its degradation. We also discovered that UBE4A participated in the degradation of P53, and knockdown of PTBP3 in CRC cell lines increased P53 expression. Overexpression of UBE4A rescued PTBP3 knockdown-induced inhibition of CRC cell proliferation and P53 expression. Conclusions PTBP3 plays an essential role in CRC cell proliferation by stabilizing UBE4A to regulate P53 expression and may serve as a new prognostic biomarker and effective therapeutic target for CRC.

Cisplatin (DDP) resistance is an important factor that decreases the effect of chemotherapy, thus leading to local recurrence and lymph node metastasis of hypopharyngeal squamous cell carcinoma (HSCC). We aimed to explore the role and mechanism of extrachromosomal circular DNA (eccDNA) in the DDP resistance of HSCC. In our research, the HSCC cell line FaDu and the DDP-resistant cell line FaDu/DDP were used as subjects. eccDNA sequencing and whole transcriptome sequencing were conducted, followed by a combined analysis of the two sequencing profiles. Outward PCR, inward PCR and Sanger sequencing were used to verify sequences of the eccDNAs. Bioinformatics analysis based on TCGA/GEO was performed in addition to plasmid transfection, RNA interference, qRT-PCR and Western blot experiments to verify the expression level of RAB3B amplified from eccDNA. mRFP-GFP-LC3 adenoviral particle transfection and transmission electron microscopy were used to detect autophagic flux. Finally, we evaluated the role of RAB3B in FaDu/DDP cells and patient-derived organoids. Our results showed that we purified and sequenced more than 10 thousand eccDNAs from the two cell lines, and the size of the eccDNAs was distributed from 0.01 kb to 1000 kb. The combined analysis between eccDNA and transcript sequencing indicated that there were some highly expressed genes that were completely or partially transcribed from related sequences of eccDNAs and not from genome linear DNA. We further screened and verified the encoding gene RAB3B using full-length sequences that might be amplified from eccDNA [chr1circle 46219-52682 kb]. Finally, we confirmed that RAB3B could promote DDP resistance in HSCC by inducing autophagy. The eccDNA might play significant roles in DDP resistance in HSCC by amplifying related functional genes. Further study is needed to explore the novel mechanisms of eccDNA in the drug resistance of HSCC.

Background In clinical practice, we often encounter patients with concurrent papillary thyroid carcinoma (PTC) and nodular goitre (NG). What are the similarities and differences between these patients and patients with simple NG? Whether NG-related nodules can affect the occurrence and development of PTC still remains unknown. Methods We retrospectively analysed 650 patients undergoing surgery for a thyroid nodule in our hospital from January 1, 2015, to January 31, 2016. A total of 574 patients who met the inclusion criteria were divided into the NG, PTC and NG&PTC groups according to their postoperative pathological features. SPSS 22 software was used to compare the characteristics of patients between the three groups, the similarities and differences of potential risk factors (such as age, sex, residence location, BMI…) and thyroid function between the NG&PTC and NG groups, and the similarities and differences of tumour pathological features between the NG&PTC and PTC groups. Results There were significant differences in the composition ratios of age, gender and residence location between the NG, PTC and NG&PTC groups. There were significant differences in residence location and body mass index (BMI) between the NG group and the NG&PTC group. There were significant differences in the number of cancer nodules, lymph node metastasis, and central lymph node metastasis between the NG&PTC and PTC groups. Conclusions Overweight may affect the occurrence of PTC in patients with NG. NG may limit the intra- or extra-glandular metastasis of PTC but does not affect the growth and invasion of PTC.

Necroptosis is a newly defined form of programmed cell death that plays an important role in cancers. However, necroptosis-related lncRNAs (NRLs) involved in colorectal cancer (CRC) have not yet been thoroughly studied. Methods: In this study, a 4-NRL model was developed based on the least absolute shrinkage and selection operator (LASSO) algorithm. A series of informatic, in vitro and in vivo analyses were applied to validate the prognostic value of the model and the potential function of the hub lncRNA MYOSLID. Results: The model exhibited an excellent capacity for the prediction of overall survival and other clinicopathological features of CRC patients using Kaplan–Meier (K–M) survival curves and receiver operating characteristic (ROC) curves. Furthermore, a significant difference in the levels of immune cells, such as CD4 memory T cells and activated mast cells, between two risk groups was observed. The low-risk patients had a higher expression of immune checkpoints, such as PDCD1 (PD-1) and CD274 (PD-L1). The levels of MYOSLID, a hub lncRNA in our model, were higher in CRC tissues than in normal tissues. Knockdown of MYOSLID induced necroptosis and inhibited the proliferation of CRC cells in vitro and in vivo. Interestingly, knockdown of MYOSLID also increased the percentage of CD4+ and CD8+ T cells in subcutaneously transplanted tumours. Conclusion: Our model is a promising biomarker that can be used to predict clinical outcomes in CRC patients, and MYOSLID plays an important role in regulating necroptosis and immune cell infiltration in CRC.

Colorectal cancer (CRC) is a common hereditary tumor that is often fatal. Its pathogenesis involves multiple genes, including circular RNAs (circRNAs). Notably, circRNAs constitute a new class of noncoding RNAs (ncRNAs) with a covalently closed loop structure and have been characterized as stable, conserved molecules that are abundantly expressed in tissue/development-specific patterns in eukaryotes. Based on accumulating evidence, circRNAs are aberrantly expressed in CRC tissues, cells, exosomes, and blood from patients with CRC. Moreover, numerous circRNAs have been identified as either oncogenes or tumor suppressors that mediate tumorigenesis, metastasis and chemoradiation resistance in CRC. Although the regulatory mechanisms of circRNA biogenesis and functions remain fairly elusive, interesting results have been obtained in studies investigating CRC. In particular, the expression of circRNAs in CRC is comprehensively modulated by multiple factors, such as splicing factors, transcription factors, specific enzymes and cis-acting elements. More importantly, circRNAs exert pivotal effects on CRC through various mechanisms, including acting as miRNA sponges or decoys, interacting with RNA binding proteins, and even translating functional peptides. Finally, circRNAs may serve as promising diagnostic and prognostic biomarkers and potential therapeutic targets in the clinical practice of CRC. In this review, we discuss the dysregulation, functions and clinical significance of circRNAs in CRC and further discuss the molecular mechanisms by which circRNAs exert their functions and how their expression is regulated. Based on this review, we hope to reveal the functions of circRNAs in the initiation and progression of cancer and highlight the future perspectives on strategies targeting circRNAs in cancer research. Supplementary Information The online version contains supplementary material available at 10.1186/s12943-021-01318-6.

MicroRNAs (miRNAs) and their target genes have been shown to play an important role in gastric cancer but have not been fully clarified. Therefore, our goal was to identify the key miRNA–mRNA regulatory network in gastric cancer by utilizing a variety of bioinformatics analyses and experiments. A total of 242 miRNAs and 1080 genes were screened from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), respectively. Then, survival-related differentially expressed miRNAs and their differentially expressed target genes were screened. Twenty hub genes were identified from their protein–protein interaction network. After weighted gene co-expression network analysis was conducted, we selected miR-137-3p and its target gene, COL5A1, for further research. We found that miR-137-3p was significantly downregulated and that overexpression of miR-137-3p suppressed the proliferation, invasion, and migration of gastric cancer cells. Furthermore, we found that its target gene, COL5A1, could regulate the expression of another hub gene, FSTL1, by sponging miR-137-3p, which was confirmed by dual-luciferase reporter assays. Knockdown of COL5A1 inhibited the proliferation, invasion, and migration of gastric cancer cells, which could be rescued by the miR-137-3p inhibitor or overexpression of FSTL1. Ultimately, bioinformatics analyses showed that the expression of FSTL1 was highly correlated with immune infiltration.

The long noncoding RNA (lncRNA) LUCAT1 was recently reported to be upregulated and to play an essential role in multiple cancer types, especially colorectal cancer (CRC), but the molecular mechanisms of LUCAT1 in CRC are mostly unreported. Here, a systematic analysis of LUACT1 expression is performed with data from TCGA database and clinic CRC samples. LUCAT1 is identified as a putative oncogene, which is significantly upregulated in CRC and is associated with poor prognosis. Loss of LUCAT1 restricts CRC proliferative capacities in vitro and in vivo. Mechanically, NCL is identified as the protein binding partner of LUCAT1 by using chromatin isolation by RNA purification coupled with mass spectrometry (ChIRP-MS) and RNA immunoprecipitation assays. We also show that NCL directly binds to LUCAT1 via its putative G-quadruplex-forming regions from nucleotides 717 to 746. The interaction between LUCAT1 and NCL interferes NCL-mediated inhibition of MYC and promote the expression of MYC. Cells lacking LUCAT1 show a decreased MYC expression, and NCL knockdown rescue LUCAT1 depletion-induced inhibition of CRC cell proliferation and MYC expression. Our results suggest that LUCAT1 plays a critical role in CRC cell proliferation by inhibiting the function of NCL via its G-quadruplex structure and may serve as a new prognostic biomarker and effective therapeutic target for CRC.

Background Circular RNAs (circRNAs) are a novel class of noncoding RNAs. Increasing evidence indicates that circRNAs play an important role in the occurrence and development of tumors. However, the role of circRNA hsa_circ_0044556 in the progression of colorectal cancer (CRC) remains unclear. Methods First, we searched for differentially expressed circRNAs using a circRNA microarray in paired CRC and adjacent normal tissues. The circRNA hsa_circ_0044556 was screened out from the existing CRC circRNA microarray in the Gene Expression Omnibus database and our microarray. The clinical significance of hsa_circ_0044556 expression level in CRC patients was then investigated. Finally, the functions of the targets of this circRNA were determined in CRC cell lines. Results Hsa_circ_0044556 was highly expressed in CRC patients and was positively correlated with tumor stage and lymph node metastasis. In CRC cell lines, the proliferation, migration, and invasion of cancer cells were inhibited by knocking down hsa_circ_0044556 expression. Conclusion Hsa_circ_0044556 promoted the progression of CRC. It is possible that hsa_circ_0044556 will become a novel biomarker or therapeutic target for CRC.

Chunxing Yang,1,* Daojiang Li,1,* Yang Bai,1 Shenglei Song,1 Peicheng Yan,1 Runliu Wu,1 Yi Zhang,1 Gui Hu,1 Changwei Lin,1 Xiaorong Li,1 Lihuang Huang2 1Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, Changsha, Hunan Province, China; 2Department of Central laboratory, The Third Xiangya Hospital of Central South University, Changsha, Hunan Province, China *These authors contributed equally to this work Background: Cancer stem cells (CSCs) are responsible for all important characteristics of tumors. DEAD-box helicase 27 (DDX27) is a member of the DEAD-box RNA helicase family, and there have been only a few studies on DDX27 function in cancer cells. This study is aimed at exploring whether DDX27 has any relation to tumorigenesis of colorectal cancer (CRC) and elucidating the potential mechanism. Methods: Data from Catalog Of Somatic Mutations In Cancer, Gene Expression Omnibus, and The Cancer Genome Atlas databases reveal that DDX27 is overexpressed in CRC tissues. qRT-PCR and Western blots were used to evaluate the expression level of DDX27 in 40 paired clinical CRC samples. DDX27 was knockdown in HT29 and HCT116 cell line with shRNA. Then CCK-8, colony formation assay and flow cytometry assay were performed to examine proliferative ability, cell cycle and sensitivity to 5-fluorouracil. Sphere-formation assay and in vivo subcutaneous tumor-formation assay were used to assess self-renewal in vitro and vivo as well as the tumor-initiating potential. Results: DDX27 is upregulated in CRC tissues and downregulation of DDX27 inhibits proliferation of colorectal cancer cell and promotes sensitivity to 5-fluorouracil. Downregulation of DDX27 can downregulate the gene expression of known CSC markers in CRC cells, inhibit sphere-formation ability, and promote colonosphere differentiation. Downregulation of DDX27 in CSCs can decrease the tumor-initiating ability of CRC cells in vivo. Conclusion: DDX27 may play a tumorpromoter role of CRC by regulating the stem cell-like activity of CRC cells. Keywords: DDX27, cancer stem cell, colonosphere, tumor-initiating ability

Sonodynamic therapy (SDT), which involves a combination of low-intensity ultrasound (US) and a chemical sonosensitizer, has emerged as a promising minimally invasive and selective approach for the treatment of deep tumors. US not only increases cell membrane permeability, thereby enhancing the cellular uptake efficiency of chemical sonosensitizers, but also excites chemical sonosensitizers in deep tissues to generate reactive oxygen species (ROS), which in turn kill cancer cells. As compared with inorganic materials, organic sonosensitizers exhibit a defined chemical structure, controlled synthesis process, excellent biodegradability, and high ROS generation. However, they frequently exhibit poor water solubility, strong phototoxicity, and low tumor tissue targeting capacity. In this review, we address the currently accepted mechanisms in SDT and the recent progresses in organic sonosensitizers, discuss the strategies to improve the water solubility, tumor targeting capacity, biocompatibility, and therapeutic effects of organic sonosensitizers. The advantages of combining SDT with other cancer treatments, including phototherapy, chemodynamic therapy, chemotherapy, starvation therapy, gas therapy, and immune therapy are also demonstrated. Finally, the existing challenges and future perspectives on clinical SDT of tumor are discussed.

YTH N6-methyladenosine (m6A) RNA binding protein 1 (YTHDF1) is a core factor in RNA methylation modification. Recent studies have shown that m6A is closely related to multiple tumors, thus YTHDF1 may also play a role in tumorigenesis. This study, aimed to explore the role of YTHDF1 in the colorectal cancer (CRC). In this study, we identified YTHDF1 as being highly expressed at the mRNA and protein levels in TCGA, GEO CRC and primary CRC. Furthermore, the YTHDF1 gene copy number was positively correlated with YTHDF1 mRNA expression in CRC. Knocking down the expression of YTHDF1 significantly inhibited the CRC cell's tumorigenicity in vitro and murine xenograft tumor growth in vivo. Furthermore, silencing of YTHDF1 inhibited the colonosphere formation ability in vitro. Mechanistically, we found that silencing YTHDF1 significantly inhibited Wnt/β-catenin pathway activity in CRC cells. Together, YTHDF1 is overexpressed in CRC and plays a vital oncogenic role in CRC, and this novel finding may provide a potential therapeutic target for CRC.

Research on DNA methylation offers great potential for the identification of biomarkers that can be applied for accurately assessing an individual's risk for cancer. In this article, we try to find the ideal epigenetic genes involved in colorectal cancer (CRC) based on a CRC database and our CRC cohort. The top 20 genes with an extremely high frequency of hypermethylation in CRC were identified in the latest database. Remarkably, 3 HOXA genes were included in this list and ranked at the top. The percentage of methylation in the HOXA5, HOXA2, and HOXA6 genes in CRC were up to 67.62, 58.36, and 31.32%, respectively, and ranked first in CRC among all human tumor tissues. Paired colorectal tumor samples and adjacent non-tumor colorectal tissue samples and four CRC cell lines were selected for MethylTarget™ assays. The results demonstrated that CRC tissues and cells had a stronger methylation status around the 3 HOXA gene promoter regions compared with adjacent non-tumor colonic tissue samples. The Receiver operator characteristic curve (ROC) curves for HOXA genes show excellent diagnostic ability in distinguishing tissue from healthy individuals and CRC patients, especially for Stage I patients (AUC = 0.9979 in HOXA2, 0.9309 in HOXA5, and 0.8025 in HOXA6). An association analysis between the methylation pattern of HOXA genes and clinical indicators was performed and found that HOXA2 methylation was significantly associated with age, N, stage, M, lymphovascular invasion, perineural invasion, lymph node number. HOXA5 methylation was associated with age, T, M, stage, and tumor status, and HOXA6 methylation was associated with age and KRAS mutation. Notably, we found that the highest methylation of HOXA5 and HOXA2 occurs in the early stages of colorectal cancer tissues such as stage I, N0, MO, and non-invasive tissues. The methylation levels declined as tumors progressed. However, methylation level at any stage of the tumor was still significantly higher than in normal tissues (p < 0.0001). The mRNA of the 3 HOXA genes was downregulated in early tumor stages due to hypermethylation of CpG islands adjacent to the promoters of the genes. In addition, hypermethylation of HOXA5 and HOXA6 mainly occurred in patients < 60 years old and with MSI-L, MSS, CIMP.L and non-CIMP tumors. Together, this suggests that epigenetic silencing of 3 adjacent HOXA genes may be an important event in the progression of colorectal cancer.

Background Our previous study revealed that PLAGL2 or POFUT1 can promote tumorigenesis and maintain significant positive correlations in colorectal cancer (CRC). However, the mechanism leading to the co-expression and the underlying functional and biological implications remain unclear. Methods Clinical tumor tissues and TCGA dataset were utilized to analyze the co-expression of PLAGL2 and POFUT1. Luciferase reporter assays, specially made bidirectional promoter vectors and ectopic expression of 3’UTR were employed to study the mechanisms of co-expression. In vitro and in vivo assays were performed to further confirm the oncogenic function of both. The sphere formation assay, immunofluorescence, Western blot and qRT-PCR were performed to investigate the effect of both genes in colorectal cancer stem cells (CSCs). Findings PLAGL2 and POFUT1 maintained co-expression in CRC (r = 0.91, p

// Jing Dai 1 * , Hao Wu 1 * , Yi Zhang 1 , Kai Gao 1 , Gui Hu 1 , Yihang guo 1 , Changwei Lin 1 , Xiaorong Li 1 1 Department of Gastrointestinal and Thyroid Surgery, The Third Xiang Ya Hospital of Central South University, Changsha, Hunan 410013, P. R. China * These authors have contributed equally to this work Correspondence to: Xiaorong Li, email: lixiaorong@medmail.com.cn Changwei Lin, email: linchangwei1987@csu.edu.cn Keywords: TAp63, miR-133b, negative feedback, proliferation, metastasis Received: February 4, 2016 Accepted: October 16, 2016 Published: November 23, 2016 ABSTRACT Background: TAp63 is known as the most potent transcription activator and tumor suppressor. microRNAs (miRNAs) are increasingly recognized as essential components of the p63 pathway, mediating downstream post-transcriptional gene repression. The aim of present study was to investigate a negative feedback loop between TAp63 and miR-133b. Results: Overexpression of TAp63 inhibited HCT-116 cell proliferation, apoptosis and invasion via miR-133b. Accordingly, miR-133b inhibited TAp63 expression through RhoA and its downstream pathways. Moreover, we demonstrated that TAp63/miR-133b could inhibit colorectal cancer proliferation and metastasis in vivo and vitro. Materials and Methods: We evaluated the correlation between TAp63 and miR-133b in HCT-116 cells and investigated the roles of the TAp63/miR-133b feedback loop in cell proliferation, apoptosis and metastasis via MTT, flow cytometry, Transwell, and nude mouse xenograft experiments. The expression of TAp63, miR-133b, RhoA, α-tubulin and Akt was assessed via qRT-PCR, western blot and immunofluorescence analyses. miR-133b target genes were identified through luciferase reporter assays. Conclusions: miR-133b plays an important role in the anti-tumor effects of TAp63 in colorectal cancer. miR-133b may represent a tiemolecule between TAp63 and RhoA, forming a TAp63/miR-133b/RhoA negative feedback loop, which could significantly inhibit proliferation, apoptosis and metastasis.

Shenglei Song, Daojiang Li, Chunxing Yang, Peicheng Yan, Yang Bai, Yi Zhang, Gui Hu, Changwei Lin, Xiaorong Li Department of Gastrointestinal Surgery, The Third Xiang Ya Hospital of Central South University, Changsha, Hunan 410013, China Purpose: Negative elongation factor complex member C/D (NELFCD), mapped to chromosome 20q13.32, has been found to be significantly overexpressed in colorectal cancer (CRC) by our previous research. However, whether its overexpression contributes to CRC development is unknown. We aimed to explore the biological and clinical roles of NELFCD in CRC.Materials and methods: The expression of NELFCD was detected by qRT-PCR and Western blot. The biological function of NELFCD on CRC cell proliferation, migration, invasion, and apoptosis was detected by cell counting kit-8, plate colony formation assay, transwell migration and invasion assays, and flow cytometry in vitro and by murine xenograft tumor growth in vivo. Moreover, we evaluated the correction between its expression level and clinicopathologic parameters.Results: We found NELFCD was overexpressed in 50 pairs of CRC tissues in comparison to the adjacent nontumor tissues (P

Long noncoding RNAs (lncRNAs) have been indicated as important regulators in various human cancers. However, the overall biological roles and clinical significance of most lncRNAs in colon carcinogenesis are not fully understood. Hence, we investigated the clinical significance, biological function and mechanism of LINC01234 in colon cancer. First, we analyzed LINC01234 alterations in colon cancer tissues and corresponding paracancerous tissues through the analysis of sequencing data obtained from The Cancer Genome Atlas and colon cancer patients. Next, we evaluated the effect of LINC01234 on colon cancer cell proliferation and its regulatory mechanism of serine hydroxymethyltransferase 2 (SHMT2) by acting as a competing endogenous RNA (ceRNA). We found that LINC01234 expression was significantly upregulated in colon cancer tissues and was associated with a shorter survival time. Furthermore, the knockdown of LINC01234 induced proliferation arrest via suppressing serine/glycine metabolism. Mechanistic investigations have indicated that LINC01234 functions as a ceRNA for miR-642a-5p, thereby leading to the derepression of its endogenous target serine hydroxymethyltransferase 2 (SHMT2). LINC01234 is significantly overexpressed in colon cancer, and the LINC01234–miR642a-5p–SHMT2 axis plays a critical role in colon cancer proliferation. Our findings may provide a potential new target for colon cancer diagnosis and therapy.

The biological functions of long non‑coding RNAs (lncRNAs) in cancer have not been fully elucidated. The present study demonstrated that the expression of a newly identified lncRNA, RP1‑85F18.6, was upregulated in colorectal cancer (CRC) tissues and cell lines. Knockdown of lncRNA RP1‑85F18.6 served a key role in tumor inhibition, reduced cell proliferation and invasion, disrupted the cell cycle, and increased apoptosis and pyroptosis of CRC cells. Conversely, overexpression of lncRNA RP1‑85F18.6 exerted the opposite effects. Furthermore, silencing lncRNA RP1‑85F18.6 decreased ΔNp63 expression at both the mRNA and protein levels. Furthermore, co‑transfection with ΔNp63 siRNA and lncRNA RP1‑85F18.6‑expressing vector attenuated the tumor‑promoting effects of lncRNA RP1‑85F18.6 overexpression. The expression levels of lncRNA RP1‑85F18.6, ΔNp63 and gasdermin D (GSDMD) were revealed to be associated with lymph node and distant metastases in patients with CRC, and therefore may serve as predictors in CRC. The findings of the present study suggested that lncRNA RP1‑85F18.6 may trigger CRC cell proliferation, invasion and cell cycle disruption, and suppress apoptosis and pyroptosis of CRC cells through regulating ΔNp63 expression. Therefore, lncRNA RP1‑85F18.6 and ΔNp63 may be considered unfavorable biomarkers, whereas GSDMD may be a favorable biomarker in CRC; these markers may prove valuable in the future diagnosis and prognosis of CRC.

Background Colorectal cancer mainly metastasizes through the lymphatic pathways and is associated with a high mortality rate. It is one of the leading causes of cancer-related deaths. In this study, the effects of long non-coding RNA (lncRNA) ENSG00000231881 on the metastasis of colorectal cancer cells were evaluated. Methods The expression level of ENSG00000231881 in colorectal cancer tissues was detected with bioinformatics analysis and quantitative polymerase chain reaction (qPCR) assay. Functional colorectal cancer cell models for the overexpression and interference expression of ENSG00000231881 were established. MTT, transwell, tube formation, qPCR, and western blot assays were performed to detect changes in various cellular functions and expression levels of key factors (miR-133b and vascular endothelial growth factor C [VEGFC]) in ENSG00000231881 functional models. Dual luciferase assay was performed to verify the binding relationship between ENSG00000231881 and miR-133b. Results ENSG00000231881 expression level was substantially higher in colorectal cancer tissues than in paracancerous tissues and correlated with malignancy and prognosis. In colorectal cancer cells, ENSG00000231881 overexpression significantly promoted cell proliferation, metastasis, and tube formation in lymphatic epithelium, decreased miR-133b expression, and increased VEGFC expression. On the contrary, ENSG00000231881 interference expression showed exactly opposite results. ENSG00000231881 could bind to miR-133b and consequently affect the cell functions through the regulation of VEGFC expression via miR-133b. Conclusion ENSG00000231881 binds to miR-133b via competitive endogenous RNA (ceRNA) mechanism and regulates the VEGFC signaling pathway, consequently leading to the metastasis of colorectal cancer cells. Our study provides a theoretical basis for the use of ENSG00000231881 as a therapeutic target for gene-targeted therapy in colorectal cancer.

Copy number variations (CNVs) are key drivers of colorectal cancer (CRC). Our previous studies revealed that protein O-fucosyltransferase 1 (POFUT1) overexpression is driven by CNVs during CRC development. The potential role and underlying mechanisms of POFUT1 in CRC were not investigated. In this study, we analyzed the expression of POFUT1 in CRC from cosmic and TCGA databases and confirmed that POFUT1 is highly expressed in CRC. We used well characterized CRC cell lines, including SW620 and HCT116 to establish a model POFUT1 knockdown cell line. Using these cells, we investigated the role of POFUT1 in CRC. Our data revealed that silencing POFUT1 in CRC cells inhibits cell proliferation, decreases cell invasion and migration, arrests cell cycle progression, and stimulates CRC cell apoptosis in vitro. We further demonstrate that POFUT1 silencing dramatically suppresses CRC tumor growth and transplantation in vivo. We additionally reveal new mechanistic insights into the role of POFUT1 during CRC, through demonstrating that POFUT1 silencing inhibits Notch1 signaling. Taken together, our findings demonstrate that POFUT1 is a tumor activating gene during CRC development, which positively regulates CRC tumor progression through activating Notch1.

Researchers hold the view that PLAGL2 is overexpressed in many malignancies and that it can promote tumor proliferation, migration, invasion and self‑renewal; however, there is no evidence revealing a relationship between PLAGL2 and colorectal cancer (CRC). In the present study, genes that are overexpressed in CRC were screened using the COSMIC database and GEPIA database and the expression of PLAGL2 in carcinoma tissues and pericarcinomatous tissues was detected by RT‑qPCR and western blot assays. A Cell Counting Kit‑8 assay, a cell cycle analysis experiment and a xenograft model were used to explore the influence of PLAGL2 on CRC after knocking down PLAGL2 expression in HCT116 and SW480 cells. Using ChIP assays and Dual‑Luciferase Reporter assays, the promoter regions to which PLAGL2 binds were discovered. It was observed that PLAGL2 was overexpressed in colorectal cancer and that it influenced the colorectal cancer cell cycle and promoted colorectal cancer proliferation in vivo and in vitro. The expression of some genes in the Wnt/β‑catenin pathway, were downregulated after knocking down the expression of PLAGL2; Wnt6 was altered the most. PLAGL2 could bind to the promoter region of Wnt6 and promote its expression. These results indicated that PLAGL2 was overexpressed in CRC as a proto‑oncogene and that it could active the Wnt/β‑catenin pathway as a transcription factor by binding with the promoter region of Wnt6. PALGL2 was revealed to play an important role in colorectal cancer and may be a new therapeutic target for targeted medicine.

Background Abnormal expression of long non-coding RNA (lncRNAs) often facilitates unrestricted growth of cancer cells. Long intergenic non-protein coding RNA 1510, an enhancer lncRNA (LINC01510), a lncRNA enhancer is upregulated in colorectal cancer (CRC), and its expression might relate to MET as revealed by lncRNA microarray data. However, the potential biological role of LINC01510 and its regulatory mechanism in CRC remain unclear. Therefore, we investigated the involvement of LINC01510 in the proliferation of CRC cells. Methods Microarray analysis, In situ hybridization, colony formation assay, MTT assay, Western blotting, quantitative RT-PCR and flow cytometry were applied. The two-tailed Student’s t test and analysis of variance or general linear model of single factor variable was used for statistical analyse. Results In the present study, we found that LINC01510 was significantly upregulated in CRC tissues and cell lines. The LINC01510 expression level were associated with the clinicopathological grade and stage. Meanwhile, gain- and loss-of-function assays demonstrated that LINC01510 overexpression increased CRC cell proliferation, and promoted cell cycle progression from the G1 phase to the S phase. Further study indicated that LINC01510 was positively correlated with the expression of MET, and its effects were most likely at the transcriptional level. Conclusions Taken together, our findings suggested that upregulation of LINC01510 contributes to the proliferation of CRC cells, at least in part, through the regulation of MET protein. LINC01510 could be a candidate prognostic biomarker and a target for new therapies in CRC patients.

The dysregulation of microRNA (miRNA) expression is highly involved in cancer. Recently, a number of studies have demonstrated that the silencing of specific miRNAs is associated with DNA methylation. The muscle-specific miRNA-113b (miR-133b) is markedly downregulated in human colorectal cancer (CRC) compared with healthy colon cells, and is critical in the regulation of CRC cell proliferation and apoptosis. However, the mechanism of miR-133b downregulation in CRC has yet to be elucidated. Therefore, the aim of the present study was to determine the existence of an association between DNA methylation and miR-133b expression in CRC cells. It was identified that miR-133b promoter hypermethylation is upregulated in CRC tissues. To investigate the role of miR-133b methylation in CRC cells, the survival, cell cycle and invasion were analyzed in HT-29 and SW620 CRC cells treated with 5-aza-2'-deoxycytidine (5-Aza-CdR), 4-phenylbutyric acid (PBA) and 5-Aza-CdR/PBA. Functional analysis demonstrated that demethylation increased the expression of miR-133b, which restored migration and apoptosis in CRC cells. Thus, these results indicate that the regulation of miR-133b methylation may provide a novel therapeutic strategy for CRC treatment.

Colorectal cancer (CRC) is one of the most common and lethal types of cancer worldwide. Multiple lines of evidence have illustrated that long non‑coding RNAs (lncRNAs) are critical molecules in the regulation of CRC development and progression. The identification of new lncRNAs is expected to provide new biomarkers and potential therapeutic targets for CRC diagnosis and prevention. Previous research has revealed that, ENST00000547547, a 434‑bp lncRNA on human chromosome12q15 (RP11‑611E13.3‑001), was found to be downregulated in CRC tissues from lncRNA microarray studies. However, its role in the development and progression of CRC remains largely unknown. In the present study, we demonstrated that the ENST00000547547 level is significantly downregulated in CRC tissues compared to normal tissues. Furthermore, the overexpression of ENST00000547547 inhibited the cell proliferation, invasion and migration of CRC cells in vitro and decreased tumorigenesis ability in vivo. Furthermore, we provided the first evidence that ENST00000547547 inhibited the proliferation of CRC cells by affecting the cell cycle and apoptosis. Finally, we demonstrated that the epithelial‑mesenchymal transition (EMT) process was associated with the inhibitory effects of ENST00000547547 on the invasion and migration of CRC cells. In summary, the present study indicated that lncRNA ENST00000547547 acted as a tumor suppressor in CRC, which may provide us with a new biomarker for CRC prognosis and a potential therapeutic target for molecular cancer therapy.

Colorectal cancer (CRC) is one of the most common cancers and the third leading cause of cancer-related deaths due to its rapid progression and poor prognosis. 5-Fluorouracil (5-FU)-based chemotherapies are the standard treatment for locally advanced CRC. However, a considerable percentage of CRCs have inherent or acquired 5-FU resistance, which critically impedes clinical outcomes. In the present study, we reported that the expression level ENST00000547547 was downregulated in 5-FU-resistant CRC cells in comparison with the parental cells, While rising with the treatment of 5-FU in parental cells. Overexpression of ENST00000547547 promoted 5-FU-induced cell apoptosis and reduced the chemoresistance of 5-FU in vitro. Moreover, we found that ENST00000547547 was a target of miR-31, as confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. Notably, miR-31 was upregulated in 5-FU-resistant CRC cells, and knockdown of miR-31 increased the chemosensitivity of 5-FU-resistant CRC cells. Furthermore, we demonstrated that ENST00000547547 reduced the chemoresistance of 5-FU via competitive binding to miR-31 in 5-FU-resistant CRC cell lines. Collectively, our findings revealed that ENST00000547547 reduced chemoresistance in 5-FU of 5-FU-resistant CRC cells through competitive binding to miR-31 and has the potential to serve as a therapeutic target in CRC patients.

Accumulating evidence indicates that dysregulation of microRNA-133b (miR-133b) is an important step in the development of certain types of human cancer and contributes to tumorigenesis. Altered expression of miR-133b has been reported in colon carcinoma, but its association with clinical stage in colorectal cancer (CRC) has remained elusive. Connective tissue growth factor (CTGF), a potentially promising candidate gene for interaction with miR-133b, was screened using micro- array analysis. The expression of miR-133b and CTGF was evaluated using reverse transcription-quantitative polymerase chain reaction and western blot analysis. The regulatory effects of miR-133b on CTGF were evaluated using a dual-luciferase reporter assay. CTGF was identified as a functional target of miR-133b. The results demonstrated low expression of miR-133b in CRC specimens with poor cell differentiation (P=0.011), lymph node metastasis (P=0.037) and advanced clinical stages (stage III or IV vs. I or II; P=0.036). Furthermore, there was a significant association between a high level of expression of CTGF mRNA and an advanced clinical stage (stage III or IV vs. I or II; P=0.015) and lymph node metastasis (P=0.034). CTGF expression was negatively regulated by miR-133b in the human colorectum, suggesting that miR-133b and CTGF may be candi- date therapeutic targets in colorectal cancer.

Aims The EZH2 gene, which is expressed in various solid tumours, including liver cancer, can regulate gene transcription and promote the generation and progression of tumours. Our aim was to investigate the relationship between EZH2 and multidrug-resistance of human hepatic cancer cells using RNA interference. Main methods We detected the expression of EZH2 in the human hepatic multidrug-resistant cancer cell line Bel/Fu by RT-PCR and western blot; then knocked EZH2 gene by RNA interference to investigate the proliferation, the cell cycle and cell apoptosis by MTT and flow cytometry; finally we checked the alteration of MDR1 methylation and MDR1 expression after EZH2 silencing by MS-PCR, RT-PCR and western blot. Key findings EZH2 is highly expressed in Bel/Fu cells. After EZH2-depleted Bel/Fu cells were treated with 5-Fu, the cell proliferation was inhibited, the cell cycle arrested at G1, which may be associated with the alteration of G1/S checkpoint regulators, meanwhile the apoptotic rate of the cells increased. Furthermore, the expression of MDR1 decreased and the corresponding methylation levels of MDR1 were significantly increased in EZH2-depleted Bel/Fu cells. Significance We demonstrate the relationship between EZH2 and multidrug-resistance in hepatic cancer for the first time. EZH2 may become a new target for gene therapy to reverse multidrug-resistance in hepatic cancer.

Objectives Chemoresistance development represents a major obstacle to the successful treatment of colorectal cancer (CRC). The aim of this study was to elucidate the mechanism by which miR-506 reverses oxaliplatin chemoresistance in CRC. Methods In this study, miR-506 levels were measured in 74 patients with colon cancer via quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). We subsequently analysed the relationship between miR-506 expression and CRC patient survival via the Kaplan-Meier method. MTT assay demonstrated the fractional survival rates and cell viability of HCT116-OxR, HCT116-OxR-miR-Ctrl and HCT116-OxR-miR-506 cells treated with oxaliplatin at different concentrations. Cell proliferation and apoptosis were assessed via flow cytometry (FCM) analysis and apoptosis assay. MDR1 mRNA expression and P-gp protein expression were assessed via qRT-PCR and Western blotting (WB) respectively. Immunofluorescence (IF) staining demonstrated P-gp expression in HCT116-OxR and HCT116-OxR-miR-506 cells. qRT-PCR and WB were used to detect Wnt/β-catenin pathway activity after miR-506 overexpression. Results In the present study, in ISH and qRT-PCR results demonstrated that miR-506 is weakly expressed in chemoresistant CRC tissues. The low miR-506 expression group exhibited lower 5-year OS and lower 5-year RFS than the high miR-506 expression group. miR-506 overexpression inhibited cell growth and increased oxaliplatin-induced cell apoptosis in HCT116-OxR cells, as shown via FCM and apoptosis assay. We subsequently noted low MDR1/P-gp expression in HCT116-OxR-miR-506 cells via qRT-PCR, WB and IF. Lastly, we demonstrated low MDR1/P-gp expression in HCT116-OxR-miR-506 cells via inhibition of the Wnt/β-catenin by WB, MTT and FCM analysis. Conclusion Taken together, the findings of our study demonstrate that miR-506 overexpression in HCT116-OxR cells enhances oxaliplatin sensitivity by inhibiting MDR1/P-gp expression via down-regulation of the Wnt/β-catenin pathway and thus provide a rationale for the development of miRNA-based strategies to reverse oxaliplatin resistance in CRC cells.

Downregulation of miR-133b has been reported in multiple types of malignancies including colorectal cancer (CRC). We previously confirmed that TAp63 actively translates microRNA-133b (miR-133b) transcripts. While the presence of miRNA mutations have frequently been described in CRC, most CRCs do not show any variation in the miR‑133b coding sequence. Therefore, it is important to elucidate the relationship between TAp63 and miR-133b, and identify other mediators of miR-133b downregulation in CRC. The expression of TAp63 was detected by RT-qPCR, western blotting, immunohistochemistry (IHC) and densitometric analysis using Image-Pro Plus 6.0 software in 38 CRC and corresponding non-cancerous tissues (NCTs). The expression of mature miR‑133b was determined by RT-qPCR, in situ hybridization (ISH) and densitometric analysis using Image-Pro Plus 6.0 software. The DNA from 38 CRC tissues and NCTs were screened for miR-133b mutations through sequence analysis. Compared with the NCTs, TAp63 mRNA expression was significantly lower in 21 (55.27%) tumor tissues. Compared with the NCTs, the miR‑133b expression level was significantly lower in 31 (81.58%) tumor tissues. The expression of miR‑133b was found to be positively correlated with TAp63. Loss of TAp63 and miR-133b was associated with an increased likelihood of metastatic events. The area under the ROC curve (AUC) of TAp63 for CRC was 0.623 [95% confidence interval (CI), 0.497-0.748; P=0.046], with 73.7% sensitivity and 50% specificity, respectively. The AUC of miR-133b for CRC was 0.857 (95% CI, 0.774‑0.940; P

Emerging evidence has identified the vital role of long noncoding RNAs (lncRNAs) in the development of colorectal cancer. In this study, we aimed to investigate the role of lncRNA gastric carcinoma highly expressed transcript 1 (GHET1) in colorectal cancer. We analyzed the expression of GHET1 in colorectal cancer (CRC) tissues by using ISH. We found that GHET1 expression was significantly increased in the CRC samples compared with adjacent tissues. Furthermore, the cancer tissues had higher GHET1 mRNA levels than their matched adjacent tissues. GHET1 expression was also significantly increased in the CRC cell lines compared with human normal colon epithelial cells. Downregulation of GHET1 mediated by shRNA suppressed the proliferation, cell cycle arrest, migration, and invasion of colorectal cancer cells in vitro. In addition, inhibition of GHET1 reversed the epithelial‐mesenchymal transition in colorectal cancer cell lines. Taken together, our results suggest the potential use of GHET1 as a therapeutic target of colorectal cancer.

The P2X7 receptor (P2X7R) is a nucleotide receptor expressed predominantly on hemopoietic, bone, and epithelial cells. The P2X7R can be activated by extracellular ATP and induces the influx of calcium, releases cytokines, and participates in cell proliferation and apoptosis. CD44 is an adhesion molecule. The effects of CD44 include cell–cell and cell–matrix adhesion interactions, lymphocyte activation, and cell migration. Many studies have shown that P2X7R and CD44 play important roles in hematological malignancies, but no study exists regarding the relationship between P2X7R and CD44. In the present study, we characterized P388D1 cells for the surface expression of CD44 and analyzed ATP-induced shedding. The data showed that P388D1 cells express CD44. Incubation of P388D1 cells with ATP induced a rapid loss of CD44 from the P388D1 cell surface. In addition, using a receptor inhibitor and P2X7R short hairpin RNA, we showed that the loss of CD44 is mediated via the P2X7R. Finally, we demonstrated that activation of P2X7R by ATP induces CD44 shedding. Copyright © 2011 John Wiley & Sons, Ltd.

Apoptosis-associated speck-like protein (ASC) is a bipartite adaptor molecule that participates in inflammation and apoptosis. ASC silencing has been observed in a significant proportion of human cancers. Here, we examined the role of ASC overexpression in the metastasis of the P388D1 murine lymphoma cell line to the liver, lung, spleen and kidney. First, we determined that the P388D1 cells express ASC. Then, ASC overexpression in P388D1 was achieved by transfecting pEGFP-ASC-C2 into the P388D1 cells. Furthermore, after the ASC-overexpressing P388D1 cells were injected into DBA/2 mice through the vena caudalis, their metastasis to the lung and the liver was significantly reduced in the pEGFP-ASC-C2-transfected group. These data indicate that ASC overexpression affects the in vivo metastatic properties of P388D1 cells. Copyright © 2011 John Wiley & Sons, Ltd.

// Yi Zhang 1, 2, * , Changwei Lin 3, * , Guoqing Liao 1 , Sheng Liu 1 , Jie Ding 4 , Fang Tang 5 , Zhenran Wang 5 , Xingsi Liang 5 , Bo Li 5 , Yangchao Wei 5 , Qi Huang 5 , Xuan Li 5 , Bo Tang 5 1 Department of Gastrointestinal Surgery, Xiangya Hospital, Central South University, 410008, PR China 2 Department of Oncological Surgery, Affiliated Hospital of Xuzhou Medical College, 221000, PR China 3 Department of Gastrointestinal Surgery, Third Xiangya Hospital, Central South University, 410008, PR China 4 Department of Gastrointestinal Surgery, Guizhou Provincial People's Hospital, 550000, PR China 5 Department of Hepatobiliary Surgery, Affiliated Hospital of Guilin Medical University, 541000, PR China * These authors have contributed equally to this work Correspondence to: Guoqing Liao, e-mail: liaoguoqing@medmail.com.cn Bo Tang, e-mail: dytangbo@163.com Keywords: miR-506, EZH2, proliferation, metastasis, colon cancer Received: March 27, 2015 Accepted: September 21, 2015 Published: October 03, 2015 ABSTRACT Increasing evidence reveals that aberrant expression of microRNA contributes to the development and progression of colon cancer, but the roles of microRNA-506 (miR-506) in colon cancer remain elusive. Here, we demonstrated that miR-506 was down-regulated in colon cancer tissue and cells and that miR-506 expression was inversely correlated with EZH2 expression, tumor size, lymph node invasion, TNM stage and metastasis. A high level of miR-506 identified patients with a favorable prognosis. In vitro and in vivo experiments confirmed that miR-506 inhibits the proliferation and metastasis of colon cancer, and a luciferase reporter assay confirmed that EZH2 is a direct and functional target of miR-506 via the 3′UTR of EZH2. The restoration of EZH2 expression partially reversed the proliferation and invasion of miR-506-overexpressing colon cancer cells. Moreover, we confirmed that the miR-506-EZH2 axis inhibits proliferation and metastasis by activating/suppressing specific downstream tumor-associated genes and the Wnt/β-catenin signaling pathway. Taking together, our study sheds light on the role of miR-506 as a suppressor for tumor growth and metastasis and raises the intriguing possibility that miR-506 may serve as a new potential marker for monitoring and treating colon cancer.

Only 3–5% of gastrointestinal stromal tumors (GISTs) are located in the duodenum. They are associated with an increased risk of fatal gastrointestinal bleeding, which is a primary manifestation. A small GIST (less than 2 cm in size) is easily confused with a duodenal papilla. In the 2 cases presented in this study, endoscopic examination alone resulted in a misdiagnoses of hemobilia. To the best of our knowledge, this is the first case report of this type in the literature. Patient 1 is a 66-year-old male who was admitted to The Second Affiliated Hospital of Dalian Medical University with syncope. Emergent upper gastrointestinal endoscopy identified bleeding from what appeared to be a duodenal papilla, and the patient was diagnosed with hemobilia. However, the angiography did not support this result. To save the patient’s life, an exploratory laparotomy was conducted. We identified a small tumor in the descending part of the duodenum and a wedge resection was successfully conducted. The final diagnosis was duodenal GIST with no further risk to the patient. Patient 2 is a 71-year-old female who was admitted to the hospital diagnosed with hemobilia. The patient underwent a barium swallow examination and a contrast-enhanced computed tomography (CT) scan, in which a tumor on the descending part of the duodenum was identified. Patient 2 also underwent a wedge resection. The final diagnosis was duodenal GIST with no further risk to the patient. Gastroscopy may be a useful procedure for duodenal GIST diagnosis; however, the endoscopic findings may be confused with hemobilia when the tumor diameter is less than 2 cm in size and heavily accompanied with blood clots. A barium swallow examination and contrast-enhanced CT may prevent a misdiagnosis of hemobilia.

Colorectal cancer (CRC) is the third most common cancer with a very poor prognosis predominantly due to its high rate of tumor invasion and migration, and its resistance to anti‑epidermal growth factor receptor (EGFR) therapy. Although CRC has been widely studied, the underlying molecular mechanism remains to be elucidated. MicroRNA (miR)‑133b has been demonstrated to act as a tumor suppressor in several human cancer types by regulating EGFR. However, the detailed involvement of miR‑133b and EGFR in CRC cells remain to be elucidated. The present study used reverse transcription quantitative polymerase chain reaction and characterized the downregulation of the expression levels of miR‑133b in CRC tissues and cell lines. Cell functional assays demonstrated that restored expression of miR‑133b inhibited the growth and invasion of CRC cells. In addition, a luciferase reporter assay revealed that miR‑133b directly targeted EGFR and repressed its expression levels in CRC cells. Additionally, combination treatment with miR‑133b mimics and the monoclonal anti‑EGFR antibody, cetuximab, which is approved and frequently used for treating patients with CRC, exhibited improved inhibitory effects on the growth and invasion of CRC cells compared with treatment with either alone. Taken together, the present study characterized the role of the miR‑133b/EGFR interaction in CRC cells and this suggested the combinational therapy with cetuximab and miR‑133b was positive and may be a potential novel treatment for patients with CRC in the future.

Hepatocellular carcinoma (HCC) is the fifth most common malignancy in the world. It is of important significance to find biomarkers for the prognostic monitoring of HCC. The 14-3-3σ and EZH2 proteins are involved in cell cycle regulation and epigenetic silencing. We herein examined the significance of 14-3-3 σ and EZH2 in HCC (n = 167) by immunohistochemistry, RT-PCR and qRT-PCR. The correlation between 14-3-3σ and EZH2 expression and patients' clinicopathologic features were examined, as was the correlation between 14-3-3σ and EZH2 expression and the prognosis of HCC patients. We found that 14-3-3σ and EZH2 were highly expressed in HCC (71% and 90%), the expression of EZH2, but not 14-3-3σ, is associated with vascular invasion and tumor differentiation (p

Objective Adhesion molecules play an important role in tumour metastasis. The liver is a frequent target for the metastasis of several tumour types. However, virtually no liver-specific adhesion molecules have been described in terms of organ-specific metastasis. This study aimed to determine the role of liver sinusoidal endothelial cell lectin (LSECtin) in colon carcinoma metastasis to the liver. Design The role of LSECtin in colon carcinoma metastasis to the liver was determined by LSECtin knockout nude mice and anti-LSECtin antibody. LSECtin promoting the migration of LS174T and LoVo cells was determined by transwell experiment. The serum levels of soluble LSECtin in patients were elevated by ELISA. Results LSECtin was found to adhere to LS174T and LoVo colon cancer cells in vitro and in vivo. Deficiency or blocking of LSECtin significantly decreased hepatic metastases of LS174T and LoVo cells. Primary colon cancer cells from patients also exhibited remarkably low rates of hepatic metastasis in LSECtin knockout mice. LSECtin promoted the migration of LS174T and LoVo cells and increased the expression of c-Met in these cells. Serum soluble LSECtin was detected at significantly higher levels in colon cancer patients with or without hepatic metastases compared with healthy controls and was also increased in colon cancer patients with metastases compared with those without metastases. Conclusion The results indicate that LSECtin plays an important role in colorectal carcinoma liver metastasis and may be a promising new target for intervention in metastasis formation.