Biology of colorectal cancer. Cancer J. 2010;16:196-201. [PMID: 20526096 DOI: 10.1097/ppo.0b013e3181e076af]

Arginine and colorectal cancer: Exploring arginine-related therapeutic strategies and novel insights into cancer immunotherapies

Concerning the progression of societies and the evolution of lifestyle and dietary habits, the potential for the development of human malignancies, particularly colorectal cancer (CRC), has markedly escalated, positioning it as one of the most prevalent and lethal forms of cancer globally. Empirical evidence indicates that the metabolic processes of cancerous and healthy cells can significantly impact immune responses and the fate of tumors. Arginine, a multifaceted amino acid, assumes a crucial and paradoxical role in various metabolic pathways, as certain tumors exhibit arginine auxotrophy while others do not. Notably, CRC is classified as arginine non-auxotrophic, possessing the ability to synthesize arginine from citrulline. Systemic arginine deprivation and the inhibition of arginine uptake represent two prevalent therapeutic strategies in oncological treatment. However, given the divergent behaviors of tumors concerning the metabolism and synthesis of arginine, one of these therapeutic approaches-namely systemic arginine deprivation-does not apply to CRC. This review elucidates the characteristics of arginine uptake inhibition and systemic arginine deprivation alongside their respective benefits and limitations in CRC. Furthermore, the involvement of arginine in immunotherapeutic strategies is examined in light of the most recent discoveries on various human malignancies.

Interactions between Dietary Antioxidants, Dietary Fiber and the Gut Microbiome: Their Putative Role in Inflammation and Cancer

The intricate relationship between the gastrointestinal (GI) microbiome and the progression of chronic non-communicable diseases underscores the significance of developing strategies to modulate the GI microbiota for promoting human health. The administration of probiotics and prebiotics represents a good strategy that enhances the population of beneficial bacteria in the intestinal lumen post-consumption, which has a positive impact on human health. In addition, dietary fibers serve as a significant energy source for bacteria inhabiting the cecum and colon. Research articles and reviews sourced from various global databases were systematically analyzed using specific phrases and keywords to investigate these relationships. There is a clear association between dietary fiber intake and improved colon function, gut motility, and reduced colorectal cancer (CRC) risk. Moreover, the state of health is reflected in the reciprocal and bidirectional relationships among food, dietary antioxidants, inflammation, and body composition. They are known for their antioxidant properties and their ability to inhibit angiogenesis, metastasis, and cell proliferation. Additionally, they promote cell survival, modulate immune and inflammatory responses, and inactivate pro-carcinogens. These actions collectively contribute to their role in cancer prevention. In different investigations, antioxidant supplements containing vitamins have been shown to lower the risk of specific cancer types. In contrast, some evidence suggests that taking antioxidant supplements can increase the risk of developing cancer. Ultimately, collaborative efforts among immunologists, clinicians, nutritionists, and dietitians are imperative for designing well-structured nutritional trials to corroborate the clinical efficacy of dietary therapy in managing inflammation and preventing carcinogenesis. This review seeks to explore the interrelationships among dietary antioxidants, dietary fiber, and the gut microbiome, with a particular focus on their potential implications in inflammation and cancer.

CBC-1 as a Cynanbungeigenin C derivative inhibits the growth of colorectal cancer through targeting Hedgehog pathway component GLI 1

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers that results in death in worldwide. The Hedgehog (HH) signalling pathway regulates the initiation and progression of CRC. Inhibiting the HH pathway has been presented as a potential treatment strategy in recent years. Cynanbungeigenin C (CBC) is a new type of C21 steroid that has been previously reported for the treatment of medulloblastoma. However, its further investigation was limited by its poor water solubility. In this study, six new CBC derivatives were synthesized through the structural modification of CBC, and four of them showed better water solubility than CBC. Moreover, their antiproliferative activities on CRC were evaluated. It was found that CBC-1 presented the best inhibitory effect on three types of CRC cell lines, and this effect was superior to that of CBC. Mechanistically, CBC-1 inhibited the proliferation of CRC cells through regulation of mRNA and proteins of the HH pathway according to qRT-PCR and Western blotting analysis. Furthermore, Cellular Thermal Shift Assay results indicated that CBC-1 regulated this signalling pathway by targeting glioma‑associated oncogene (GLI 1).In addition, cell apoptosis was induced increasingly by transfection with GLI 1 siRNA or treatment with CBC-1 to downregulate GLI 1. Last, the in vivo results demonstrated that CBC-1 significantly reduced tumour size and downregulated GLI 1 in CRC. Therefore, this study suggests that CBC-1, a new GLI 1 inhibitor derived from natural products, may be developed as a potential antitumour candidate for CRC treatment.

Emerging trends in gastrointestinal cancers: Targeting developmental pathways in carcinogenesis and tumor progression

Gastrointestinal carcinomas are a group of cancers associated with the digestive system and its accessory organs. The most prevalent cancers related to the gastrointestinal tract are colorectal, gall bladder, gastric, hepatocellular, and esophageal cancers, respectively. Molecular aberrations in different signaling pathways, such as signal transduction systems or developmental pathways are the chief triggering mechanisms in different cancers Though a massive advancement in diagnostic and therapeutic interventions results in improved survival of patients with gastrointestinal cancer; the lower malignancy stages of these carcinomas are comparatively asymptomatic. Various gastrointestinal-related cancers are detected at advanced stages, leading to deplorable prognoses and increased rates of recurrence. Recent molecular studies have elucidated the imperative roles of several signaling pathways, namely Wnt, Hedgehog, and Notch signaling pathways, play in the progression, therapeutic responsiveness, and metastasis of gastrointestinal-related cancers. This book chapter gives an interesting update on recent findings on the involvement of developmental signaling pathways their mechanistic insight in gastrointestinalcancer. Subsequently, evidences supporting the exploration of gastrointestinal cancer related molecular mechanisms have also been discussed for developing novel therapeutic strategies against these debilitating carcinomas.

Cholesterol in colorectal cancer: an essential but tumorigenic precursor?

Colorectal cancer (CRC) is one of the most lethal human malignancies, and with the growth of societies and lifestyle changes, the rate of people suffering from it increases yearly. Important factors such as genetics, family history, nutrition, lifestyle, smoking, and alcohol can play a significant role in increasing susceptibility to this cancer. On the other hand, the metabolism of several macromolecules is also involved in the fate of tumors and immune cells. The evidence discloses that cholesterol and its metabolism can play a role in the pathogenesis of several cancers because there appears to be an association between cholesterol levels and CRC, and cholesterol-lowering drugs may reduce the risk. Furthermore, changes or mutations of some involved genes in cholesterol metabolism, such as CYP7A1 as well as signaling pathways, such as mitogen-activated protein kinase (MAPK), can play a role in CRC pathogenesis. This review summarized and discussed the role of cholesterol in the pathogenesis of CRC as well as available cholesterol-related therapeutic approaches in CRC.

Fibres and Colorectal Cancer: Clinical and Molecular Evidence

Colorectal cancer (CRC) is one of the leading causes of mortality for cancer in industrialized countries. The link between diet and CRC is well-known, and presumably CRC is the type of cancer which is most influenced by dietary habits. In Western countries, an inadequate dietary intake of fibers is endemic, and this could be a driving factor in the increase of CRC incidence. Indeed, several epidemiologic studies have elucidated an inverse relationship between daily fiber intake and risk of CRC. Long-term prognosis in CRC survivors is also dependent on dietary fibers. Several pathogenetic mechanisms may be hypothesized. Fibers may interfere with the metabolism of bile acids, which may promote colon carcinogenesis. Further, fibers are often contained in vegetables which, in turn, contain large amounts of antioxidant agents like resveratrol, polyphenols, or phytoestrogens. Moreover, fibers can be digested by commensal flora, thus producing compounds such as butyrate, which exerts an antiproliferative effect. Finally, fibers may modulate gut microbiota, whose composition has shown to be associated with CRC onset. In this regard, dietary interventions based on high-fiber-containing diets are ongoing to prevent CRC development, especially in patients with high potential for this type of tumor. Despite the fact that outcomes are preliminary, encouraging results have been observed.

Evaluation of enterotoxigenic Bacteroides fragilis correlation with the expression of cellular signaling pathway genes in Iranian patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers all over the world, and dysbiosis in the gut microbiota may play a role in colorectal carcinogenesis. Bacteroides fragilis can lead to tumorigenesis by changing signaling pathways, including the WNT/β-catenin pathway. Therefore, in the present study, we investigated the correlation between the enterotoxigenic B. fragilis amount and the expression of signaling pathway genes involved in CRC.

MATERIALS AND METHODS

B. fragilis was determined in 30 tumors and adjacent healthy tissues by the qPCR method. Next, the relationship between enterotoxigenic B. fragilis and the expression of signaling pathway genes, including CCND1, TP53, BCL2, BAX, WNT, TCF, AXIN, APC, and CTNNB1 was investigated. Additionally, possible correlations between clinicopathological features of the tumor samples and the abundance of B. fragilis were analyzed.

RESULTS

The results showed that B. fragilis was detected in 100% of tumor samples and 86% of healthy tissues. Additionally, enterotoxigenic B. fragilis colonized 47% of all samples, and bft-1 toxin was the most frequently found isotype among the samples. The analysis showed that the high level of B. fragilis has a significant relationship with the high expression of AXIN, CTNNB1, and BCL2 genes. On the other hand, our results did not show any possible correlation between this bacterium and the clinicopathological features of the tumor sample.

CONCLUSION

B. fragilis had a higher abundance in the tumor samples than in healthy tissues, and this bacterium may lead to CRC by making changes in cellular signaling pathways and genes. Therefore, to better understand the physiological effects of B. fragilis on the inflammatory response and CRC, future research should focus on dissecting the molecular mechanisms by which this bacterium regulates cellular signaling pathways.

Inhibition of Cell Proliferation and Induction of Cell Cycle Arrest in Colon Cancer Cells by Lyophilized Mango (Mangifera indica L.) Pulp Extract

The present study evaluated the antiproliferative capacity and possible cell death mechanisms of lyophilized mango pulp extract (LMPE), applied to human colon cancer cells (SW480) and their metastasis-derived counterparts (SW620). The total phenolic content of LMPE was estimated by the Folin-Ciocalteu method. Three assays were employed to determine its antioxidant capacity: ferric-reducing antioxidant power, oxygen radical absorbance capacity, and 2,2-diphenyl-1-picrylhydrazyl. Furthermore, the antiproliferative activity of LMPE was assessed by sulforhodamine B, clonogenic, and Ki-67 assays. Flow cytometry was employed to examine the cell cycle, production of intracellular reactive oxygen species (ROS), cell-surface phosphatidylserine, and change in mitochondrial membrane potential. LMPE exhibited a high level of total phenolic content and antioxidant activity. The mean maximal inhibitory concentration values of LMPE at 48 h of exposure were 43 and 29 mg/mL for SW480 and SW620, respectively. In the SW480 and SW620 cell lines, LMPE at 50 mg/mL and 48 h of exposure induced an increase in intracellular ROS, cell cycle arrest in the G2/M phase, and probably, apoptotic processes without mitochondrial depolarization. LMPE had an antiproliferative capacity against the human colorectal cancer cell lines SW480 and SW620. These results highlight the chemopreventive potential of LMPE in colorectal cancer treatments.

Deep convolutional neural networks with ensemble learning and transfer learning for automated detection of gastrointestinal diseases

Gastrointestinal (GI) diseases are serious health threats to human health, and the related detection and treatment of gastrointestinal diseases place a huge burden on medical institutions. Imaging-based methods are one of the most important approaches for automated detection of gastrointestinal diseases. Although deep neural networks have shown impressive performance in a number of imaging tasks, its application to detection of gastrointestinal diseases has not been sufficiently explored. In this study, we propose a novel and practical method to detect gastrointestinal disease from wireless capsule endoscopy (WCE) images by convolutional neural networks. The proposed method utilizes three backbone networks modified and fine-tuned by transfer learning as the feature extractors, and an integrated classifier using ensemble learning is trained to detection of gastrointestinal diseases. The proposed method outperforms existing computational methods on the benchmark dataset. The case study results show that the proposed method captures discriminative information of wireless capsule endoscopy images. This work shows the potential of using deep learning-based computer vision models for effective GI disease screening.

New Insights into Bile Acids Related Signaling Pathways in the Onset of Colorectal Cancer

Colorectal cancer (CRC) ranks as the second among the causes of tumor death worldwide, with an estimation of 1.9 million new cases in 2020 and more than 900,000 deaths. This rate might increase by 60% over the next 10 years. These data are unacceptable considering that CRC could be successfully treated if diagnosed in the early stages. A high-fat diet promotes the hepatic synthesis of bile acids (BAs) increasing their delivery to the colonic lumen and numerous scientific reports correlate BAs, especially secondary BAs, with CRC incidence. We reviewed the physicochemical and biological characteristics of BAs, focusing on the major pathways involved in CRC risk and progression. We specifically pointed out the role of BAs as signaling molecules and the tangled relationships among their nuclear and membrane receptors with the big bang of molecular and cellular events that trigger CRC occurrence.

Toosendanin inhibits colorectal cancer cell growth through the Hedgehog pathway by targeting Shh

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. This complex and often fatal disease has a high mortality rate. The Hedgehog (Hh) signaling pathway is crucial in CRC. Many studies have indicated that Shh is overexpressed in cancer stem cells (CSCs), and shh overexpression is positively correlated with CRC tumorigenesis. New drugs that kill CRC cells through the Hh pathway are needed. Toosendanin (TSN), a natural triterpenoid saponin extracted from the bark or fruit of Melia toosendan Sieb. et Zucc, can inhibit various tumors. Here, we investigated the effects of TSN in CRC and explored the possible targets and mechanisms. Shh-Light Ⅱ cells were treated with TSN and tested by dual luciferase reporter assays to determine the relationship with the Hh pathway. Cell Counting Kit-8 (CCK-8) assays were used to test the inhibitory effects of TSN on CRC cells. The expression of Hh components after TSN treatment was detected using western blots and quantitative reverse transcription polymerase chain reaction. Cellular thermal shift assays confirmed the targets of TSN. The same effects of TSN on xenograft tumor growth were investigated in vivo. The average weight, volume of the finally resected tumor, and the expression of Shh in the TSN-treated groups were significantly lower than those of the control group. This result strongly suggested that TSN administration inhibited CRC growth in vivo. Our research preliminarily demonstrated that the target of TSN was Shh and that TSN inhibits CRC cell growth by inhibiting the Hh pathway, identifying a new anticancer molecular mechanism of TSN in CRC.

Consensus molecular subtype differences linking colon adenocarcinoma and obesity revealed by a cohort transcriptomic analysis

Colorectal cancer (CRC) is the third-leading cause of cancer-related deaths in the United States and worldwide. Obesity—a worldwide public health concern—is a known risk factor for cancer including CRC. However, the mechanisms underlying the link between CRC and obesity have yet to be fully elucidated in part because of the molecular heterogeneity of CRC. We hypothesized that obesity modulates CRC in a consensus molecular subtype (CMS)-dependent manner. RNA-seq data and associated tumor and patient characteristics including body weight and height data for 232 patients were obtained from The Cancer Genomic Atlas–Colon Adenocarcinoma (TCGA-COAD) database. Tumor samples were classified into the four CMSs with the CMScaller R package; body mass index (BMI) was calculated and categorized as normal, overweight, and obese. We observed a significant difference in CMS categorization between BMI categories. Differentially expressed genes (DEGs) between obese and overweight samples and normal samples differed across the CMSs, and associated prognostic analyses indicated that the DEGs had differing associations on survival. Using Gene Set Enrichment Analysis, we found differences in Hallmark gene set enrichment between obese and overweight samples and normal samples across the CMSs. We constructed Protein-Protein Interaction networks and observed differences in obesity-regulated hub genes for each CMS. Finally, we analyzed and found differences in predicted drug sensitivity between obese and overweight samples and normal samples across the CMSs. Our findings support that obesity impacts the CRC tumor transcriptome in a CMS-specific manner. The possible associations reported here are preliminary and will require validation using in vitro and animal models to examine the CMS-dependence of the genes and pathways. Once validated the obesity-linked genes and pathways may represent new therapeutic targets to treat colon cancer in a CMS-dependent manner.

Low curcumin concentration enhances the anticancer effect of 5-fluorouracil against colorectal cancer

BACKGROUND

Colon cancer treatments include surgery, radiotherapy, and chemotherapy. Chemotherapy using 5-fluorouracil (5-FU) has been widely applied to treat colorectal cancer (CRC). However, it is important to explore the use of chemotherapy drugs in combination with other agents to decrease severe adverse effects.

PURPOSE

This study aimed to investigate the effects of curcumin in combination with 5-FU on the proliferation, migration, and apoptosis of CRC SW620 cell line both in vitro and in vivo.

METHODS

Flow cytometry was used to study the effect of curcumin on chemotherapy-induced apoptosis in CRC cells. The mechanism of curcumin's enhanced antitumor effect in vivo was investigated using gene knockdown, TUNEL, western blot, qRT-PCR and immunohistochemistry.

RESULTS

The results showed a synergistic effect of the two compounds on CRC cells. Considerable reduction in the proliferation and migration of SW620 cells was observed in the combination treatment group. Significantly increased apoptosis rate extended the survival of immunodeficient mice in the combination group as compared to that of the 5-FU group (p < 0.05). The results showed that curcumin significantly inhibited pERK signaling and downregulated L1 expression in SW620 cells.

CONCLUSIONS

We conclude that curcumin promotes chemosensitivity of CRC cells to 5-FU by downregulating L1 expression. Our findings provide experimental evidence for the synergism between curcumin and 5-FU, which can be utilized in clinical applications for reducing the toxicity and adverse effects of 5-FU.

The Expression and Clinical Significance of miRNA-135a and Bach1 in Colorectal Cancer

Aim

The objective of this study was to explore the correlation between the expression of miRNA-135a and Bach1 in colorectal cancer tissue and the patient's clinical information.

Methods

Sixty patients with colorectal carcinoma were treated as a control group. Real-time quantitative polymerase chain reaction assays and immunohistochemistry methods were performed to detect the expression of miRNA-135a and Bach1 in 60 colorectal carcinomas and adjacent normal tissues, and the clinical and pathologic classifications were also investigated. SPSS 19.00 software was used. All data are represented as mean ± SD of 3 independent experiments. P &lt; 0.05 was considered statistically significant.

Results

miRNA-135a expression levels increased significantly in colon cancer tissues compared with the nontumor control tissues (P &lt; 0.01). miRNA-135a expression levels were higher in stage III/IV than in stage I/II colon cancer patients. The expression level of Bach1 in colorectal cancer was significantly lower (P &lt; 0.01). Bach1 and miRNA-135a were negatively correlated.

Conclusions

The levels of miRNA-135a and Bach1 were opposite: the overexpression of miRNA-135a might downregulate the expression of Bach1, which might be involved in the pathogenesis of colorectal cancer.

α-Mangostin-encapsulated PLGA nanoparticles inhibit colorectal cancer growth by inhibiting Notch pathway

Colorectal cancer (CRC) is the fourth leading cause of cancer‐related mortality. Recent studies have stated that Notch signalling is highly activated in cancer stem cells (CSCs) and plays an important role in the development and progression of CRC. Like normal colorectal epithelium, CRCs are organized hierarchically and include populations of CSCs. In order to enhance the biological activity of α‐mangostin, we formulated α‐mangostin‐encapsulated PLGA nanoparticles (Mang‐NPs) and examined the molecular mechanisms by which Mang‐NPs inhibit CRC cell viability, colony formation, epithelial‐mesenchymal transition (EMT) and induce apoptosis. Mang‐NPs inhibited cell viability, colony formation and induced apoptosis. Mang‐NPs also inhibited EMT by up‐regulating E‐cadherin and inhibiting N‐cadherin and transcription factors Snail, Slug and Zeb1. As dysregulated signalling through the Notch receptors promotes oncogenesis, we measured the effects of Mang‐NPs on Notch pathway. Mang‐NPs inhibited Notch signalling by suppressing the expression of Notch receptors (Notch1 and Notch2), their ligands (Jagged 1 and DLL4), γ‐secretase complex protein (Nicastrin) and downstream target (Hes‐1). Notch receptor signalling regulates cell fate determination in stem cell population. Finally, Mang‐NPs inhibited the self‐renewal capacity of CSCs, stem cell markers (CD133, CD44, Musashi and LGR5) and pluripotency maintaining factors (Oct4, Sox‐2, KLF‐4, c‐Myc and Nanog). Overall, our data suggest that Mang‐NPs can inhibit CRC growth, EMT and CSCs’ population by suppressing Notch pathway and its target. Therefore, Mang‐NPs can be used for the treatment and prevention of CRC.

Colorectal cancer (CRC) as a multifactorial disease and its causal correlations with multiple signaling pathways

Colorectal cancer (CRC) is the third most common malignancy and one of the leading causes of cancer-related death among men worldwide. CRC is a multifactor digestive pathology, which is a huge problem faced not only by clinicians but also by researchers. Importantly, a unique feature of CRC is the dysregulation of molecular signaling pathways. To date, a series of reviews have indicated that different signaling pathways are disordered and have potential as therapeutic targets in CRC. Nevertheless, an overview of the function and interaction of multiple signaling pathways in CRC is needed. Therefore, we summarized the pathways, biological functions and important interactions involved in CRC. First, we investigated the involvement of signaling pathways, including Wnt, PI3K/Akt, Hedgehog, ErbB, RHOA, Notch, BMP, Hippo, AMPK, NF-κB, MAPK and JNK. Subsequently, we discussed the biological function of these pathways in pathophysiological aspects of CRC, such as proliferation, apoptosis and metastasis. Finally, we summarized important interactions among these pathways in CRC. We believe that the interaction of these pathways could provide new strategies for the treatment of CRC.

Recycling the Interspecific Relations with Epithelial Cells: Bacteria and Cancer Metabolic Symbiosis

Several aspects of the human physiology are controlled by the microbiota that plays a key role in health and disease. In fact, microbial dysbiosis is associated with numerous diseases, including several types of cancer such as colon, gastric, esophageal, pancreatic, laryngeal, breast and gallbladder carcinomas.Metabolic symbiosis between non-malignant cells and the resident microbita is crucial for the host homeostasis. However, cancer cells are able to repurpose the pre-existing metabolic symbiosis, being able to recycle those relations and also create novel metabolic symbiosis, leading to profound alterations on the local microenvironment.In here we will explore some of these symbiotic metabolic interactions between bacteria and non-malignant cells in two different contexts: colon and uterine cervix. The way malignant cells are able to recycle these normal interactions and also create novel types of symbiotic metabolic relations will also be discussed.The knowledge of these complex interactions and recycling mechanisms is of extreme importance for cancer treatment, as new therapeutic targets could be developed.

Grape seed procyanidin B2 promotes the autophagy and apoptosis in colorectal cancer cells via regulating PI3K/Akt signaling pathway

Aim: Colorectal cancer (CRC) is a major malignancy in China, which is the critical risk of people health. Many natural herbs extracts have been found to exhibit good therapeutic effect on CRC. Our previous study found that grape seed procyanidins B2 (PB2) would induce CRC cell death. However, the molecular mechanism underlying its anti-tumor effect on CRC remains unclear. Thereby, this study aimed to investigate the anti-tumor mechanism of PB2 on CRC.

Methods: CCK-8, western blotting, flow cytometry, qRT-PCR and animal study were used in the current study.

Results: The in vitro and in vivo data demonstrated that PB2 could promote the apoptosis of CRC cells in a dose-dependent manner, which was significantly reversed by caspase 3 inhibitor. Meanwhile, PB2 dose-dependently induced autophagy in CRC cells, which was markedly attenuated by autophagy inhibitor 3-MA. In addition, PB2 dose-dependently inhibited the expressions of p-PI3K, p-Akt and p-mTOR in the cells.

Conclusion: PB2 dose-dependently induced apoptosis and autophagy in CRC cells via downregulation of PI3K/Akt pathway. This study provided the experimental basis for further development of PB2 as a new effective anticancer drug for the patients with CRC.

Histone deacetylase 6 is overexpressed and promotes tumor growth of colon cancer through regulation of the MAPK/ERK signal pathway

Purpose: To investigate the expression of histone deacetylase 6 (HDAC6) in colon cancer and its role in colon cancer cell growth and migration. Materials and methods: We detected the expression of HDAC6 in a colon cancer tissue chip using immunochemical staining, and analyzed the difference in HDAC6 expression between cancer and adjacent noncancerous tissues. Then, we explored the relationship between HDAC6 expression and patients' clinicopathological characteristics and prognoses. In adidition, the role of HDAC6 in colon cancer cell growth and migration, as well as its potential related signal pathway, through HDAC6 knockdown was explored. Results: The immunochemical score of HDAC6 expression was higher in cancer tissue than in the adjacent noncancerous tissue (4.54 vs 3.08, P<0.005); similarly, as well as the rate of high HDAC6 expression was higher in cancer tissue than in the adjacent noncancerous tissue (71.1% vs 40.9%, P<0.001). Patients showing high HDAC6 expression had a shorter overall survival time. Additionally, Cox regression analysis showed that high HDAC6 expression was an independent risk factor for poor prognosis. HDAC6 knockdown decreased cell viability, colony formation, and number of migrated colon cancer cells (HCT116 and HT29); the expression of p-MEK, p-ERK, and p-AKT was also decreased, but had no influence on MEK, ERK, and AKT expression. Conclusion: HDAC6 is highly expressed in colon cancer and associated with a poor prognosis. HDAC6 knockdown inhibits colon cancer cell growth and migration, partly through the MAPK/ERK pathway.

Increased EZH2 expression during the adenoma-carcinoma sequence in colorectal cancer

The adenoma-carcinoma sequence, the sequential mutation and deletion of various genes by which colorectal cancer progresses, is a well-established and accepted concept of colorectal cancer carcinogenesis. Proteins of the polycomb repressive complex 2 (PRC2) function as transcriptional repressors by trimethylating histone H3 at lysine 27; the activity of this complex is essential for cell proliferation and differentiation. The histone methyltransferase enhancer of zeste homolog 2 (EZH2), an essential component of PRC2, is associated with the transcriptional repression of tumor suppressor genes. EZH2 expression has previously been reported to increase with the progression of pancreatic intraductal papillary mucinous neoplasm. Thus, we hypothesized that EZH2 expression also increases during the adenoma-carcinoma sequence of colorectal cancer. The present study investigated changes in EZH2 expression during the colorectal adenoma-carcinoma sequence. A total of 47 patients with colorectal adenoma, 20 patients with carcinoma in adenoma and 43 patients with colorectal carcinoma who underwent surgical or endoscopic resection were enrolled in this study. Non-cancerous tissue from the clinical specimens was also examined. The association between EZH2 expression, pathology and expression of tumor suppressor genes during colorectal carcinogenesis were analyzed. Each specimen was immunohistochemically stained for EZH2, proliferation marker protein Ki-67 (Ki-67), cyclin-dependent kinase inhibitor (CDKN) 1A (p21), CDKN1B (p27) and CDKN2A (p16). Total RNA was extracted from formalin-fixed paraffin-embedded blocks and reverse transcription-quantitative polymerase chain reaction analysis of these genes was performed. Ki-67 and EZH2 expression scores increased significantly during the progression of normal mucosa to adenoma and carcinoma (P=0.009), and EZH2 expression score was positively associated with Ki-67 expression score (P=0.02). Conversely, p21 mRNA and protein expression decreased significantly, whereas expression of p27 and p16 did not change significantly. During the carcinogenesis sequence from normal mucosa to adenoma and carcinoma, EZH2 expression increased and p21 expression decreased significantly. EZH2 may therefore contribute to the development of colorectal cancer from adenoma via suppression of p21.

Significance of Notch and Wnt signaling for chemoresistance of colorectal cancer cells HCT116

5-fluorouracil (5-FU) and oxaliplatin (OxaPt) are the main chemotherapeutics for colorectal cancer (CRC). Chemotherapy response rates for advanced CRC remain low, primarily due to intrinsic or acquired chemoresistance. The importance of Notch and Wnt signaling for carcinogenesis of CRC as well as crosstalk of Notch and Wnt signaling with many oncogenic signaling pathways suggest that Notch and Wnt pathways could be responsible for chemoresistance. In this study, we compared changes in Notch and Wnt signaling after 5-FU and OxaPt treatment in CRC cells HCT116 and its chemoresistant sublines HCT116/FU and HCT116/OXA. The levels of Notch1 receptor intracellular domain NICD1 and non-phosphorylated β-catenin, the reporters of Notch and Wnt signaling, were upregulated in untreated chemoresistant HCT116/FU and HCT116/OXA cells. Our data suggest that Notch inhibitor RO4929097 (RO) and Wnt inhibitor XAV939 (XAV) enhance the survival potential of OxaPt-treated cells. The protein level of Notch target gene HES1 was significantly upregulated in chemoresistant HCT116/FU and HCT116/OXA cells, compared to HCT116. HES1 silencing increased viability of HCT116 and its chemoresistant sublines after 5-FU or OxaPt treatment. The results of HES1 downregulation coincide with RO and XAV effects on cell viability of OxaPt-treated cells.

Update on Sporadic Colorectal Cancer Genetics

Our understanding of the genetics of colorectal cancer has changed dramatically over recent years. Colorectal cancer can be classified in multiple different ways. Along with the advent of whole-exome sequencing, we have gained an understanding of the scale of the genetic changes found in sporadic colorectal cancer. We now know that there are multiple pathways that are commonly involved in the evolution of colorectal cancer including Wnt/β-catenin, RAS, EGFR, and PIK3 kinase. Another recent leap in our understanding of colorectal cancer genetics is the recognition that many, if not all tumors, are actually genetically heterogeneous within individual tumors and also between tumors. Recent research has revealed the prognostic and possibly therapeutic implications of various specific mutations, including specific mutations in BRAF and KRAS . There is increasing interest in the use of mutation testing for screening and surveillance through stool and circulating DNA testing. Recent advances in translational research in colorectal cancer genetics are dramatically changing our understanding of colorectal cancer and will likely change therapy and surveillance in the near future.

LDB1 overexpression is a negative prognostic factor in colorectal cancer

Background

Colorectal cancer (CRC) is the third most common cancer in western countries and is driven by the Wnt signaling pathway. LIM-domain-binding protein 1 (LDB1) interacts with the Wnt signaling pathway and has been connected to malignant diseases. We therefore aimed to evaluate the role of LDB1 in CRC.

Results

Overexpression of LDB1 in CRC is associated with strikingly reduced overall and metastasis free survival in all three independent patient cohorts. The expression of LDB1 positively correlates with genes involved in the Wnt signaling pathway (CTNNB1, AXIN2, MYC and CCND1). Overexpression of LDB1 in CRC cell lines induced Wnt pathway upregulation as well as increased invasivity and proliferation. Upon separate analysis, the role of LDB1 proved to be more prominent in proximal CRC, whereas distal CRC seems to be less influenced by LDB1.

Materials and Methods

The expression of LDB1 was measured via RT-qPCR in 59 clinical tumor and normal mucosa samples and correlated to clinical end-points. The role of LDB1 was examined in two additional large patient cohorts from publicly available microarray and RNAseq datasets. Functional characterization was done by lentiviral overexpression of LDB1 in CRC cell lines and TOP/FOP, proliferation and scratch assays.

Conclusions

LDB1 has a strong role in CRC progression, confirmed in three large, independent patient cohorts. The in vitro data confirm an influence of LDB1 on the Wnt signaling pathway and tumor cell proliferation. LDB1 seems to have a more prominent role in proximal CRC, which confirms the different biology of proximal and distal CRC.

Macrophage conditioned medium promotes colorectal cancer stem cell phenotype via the hedgehog signaling pathway

BACKGROUND

There is conflicting data on the role of macrophages in colorectal cancer (CRC); some studies have shown that macrophages can exert an anti-tumor effect whereas others show that macrophages are tumor promoting. We sought to determine the role of conditioned medium (CM) from macrophages, in particular classically activated macrophages, on the development of the CSC phenotype in CRC cells, which is believed to mediate tumor growth and chemoresistance.

METHODS

Murine (CT26) and human (HCP-1) CRC cell lines were treated with CM from lipopolysaccharide (LPS)-activated murine macrophages. The CSC population was assessed using the sphere-forming assay and aldehyde dehydrogenase assay. Chemoresistance studies were performed using the MTT assay. CSC transcription factors and SHH protein were analyzed by Western blotting.

RESULTS

The results showed that LPS-activated macrophage CM induced the CSC phenotype in CRC cells. Further studies showed that the CSC phenotype was mediated by the sonic hedgehog (SHH)-Gli signaling pathway, which is known to drive self-renewal; these effects were blocked by depletion of SHH in macrophage CM. In addition, LPS-activated macrophage CM enhanced chemoresistance.

CONCLUSIONS

LPS-activated macrophages play an active role in promoting the CSC phenotype through activation of the SHH-Gli signaling pathway in CRC cells.

The clinical and biological roles of transforming growth factor beta in colon cancer stem cells: A systematic review

BACKGROUND

Transforming growth factor beta (TGF-β) is a multipurpose cytokine, which plays a role in many cellular functions such as proliferation, differentiation, migration, apoptosis, cell adhesion and regulation of epithelial to mesenchymal transition. Despite many studies having observed the effect that TGF-β plays in colorectal cancer, its role in the colorectal stem cell population has not been widely observed.

METHOD

This systematic review will analyse the role of TGF-β in the stem cell population of colorectal cancer.

RESULTS

The effects on the stem cell phenotype are through the downstream proteins involved in activation of the TGF-β pathway. Its involvement in the initiation of the epithelial to mesenchymal transition (EMT), the effect of colorectal invasion and metastasis regulated through the Smad protein involvement in the EMT, initiation of angiogenesis, promotion of metastasis of colorectal cancer to the liver and its ability to cross-talk with other pathways.

CONCLUSION

TGF-β is a key player in angiogenesis, tumour growth and metastasis in colon cancer.

Withaferin-A suppress AKT induced tumor growth in colorectal cancer cells

The oncogenic activation of AKT gene has emerged as a key determinant of the aggressiveness of colorectal cancer (CRC); hence, research has focused on targeting AKT signaling for the treatment of advanced stages of CRC. In this study, we explored the anti-tumorigenic effects of withaferin A (WA) on CRC cells overexpressing AKT in preclinical (in vitro and in vivo) models. Our results indicated that WA, a natural compound, resulted in significant inhibition of AKT activity and led to the inhibition of cell proliferation, migration and invasion by downregulating the epithelial to mesenchymal transition (EMT) markers in CRC cells overexpressing AKT. The oral administration of WA significantly suppressed AKT-induced aggressive tumor growth in a xenograft model. Molecular analysis revealed that the decreased expression of AKT and its downstream pro-survival signaling molecules may be responsible for tumor inhibition. Further, significant inhibition of some important EMT markers, i.e., Snail, Slug, β-catenin and vimentin, was observed in WA-treated human CRC cells overexpressing AKT. Significant inhibition of micro-vessel formation and the length of vessels were evident in WA-treated tumors, which correlated with a low expression of the angiogenic marker RETIC. In conclusion, the present study emphasizes the crucial role of AKT activation in inducing cell proliferation, angiogenesis and EMT in CRC cells and suggests that WA may overcome AKT-induced cell proliferation and tumor growth in CRC.

Molecular characterization of pro-metastatic functions of β4-integrin in colorectal cancer

The β4-integrin subunit has been implicated in development and progression of several epithelial tumor types. However, its role in metastases of colorectal cancer (CRC) remains elusive. To study CRC metastasis, we generated a highly invasive, metastatic cell line MC38-LM10 (LM10) by passaging mouse CRC MC38 cells ten times, using a splenic injection model of liver metastasis. Affymetrix microarray analyses of LM10 and MC38 cell lines and their corresponding liver metastases generated a gene signature for CRC metastasis. This signature shows strong upregulation of β4-integrin in LM10 cells and corresponding metastases. Upregulation of β4-integrin in highly aggressive LM10 cells is associated with increased migration, invasion, and liver metastases. Furthermore, stable knockdown of β4-integrin in human CRC SW620 cells reduces Bcl-2 expression, increases apoptosis, and decreases invasion, tumorigenicity, and liver metastasis, thus resulting in significantly increased survival of mice (hazard ratio = 0.32, 95% confidence interval = 0.15-0.66, P<0.01). Patients with CRC tumors display higher β4-integrin levels in stages 1-4 and significantly lower survival rate. Collectively, β4-integrin plays a critical role in CRC progression, invasion, and metastasis, suggesting that it could be a potential therapeutic target for CRC patients.

Hedgehog signaling pathway in colorectal cancer: function, mechanism, and therapy

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. It is a complicated and often fatal cancer, and is related to a high disease-related mortality. Around 90% of mortalities are caused by the metastasis of CRC. Current treatment statistics shows a less than 5% 5-year survival for patients with metastatic disease. The development and metastasis of CRC involve multiple factors and mechanisms. The Hedgehog (Hh) signaling plays an important role in embryogenesis and somatic development. Abnormal activation of the Hh pathway has been proven to be related to several types of human cancers. The role of Hh signaling in CRC, however, remains controversial. In this review, we will go through previous literature on the Hh signaling and its functions in the formation, proliferation, and metastasis of CRC. We will also discuss the potential of targeting Hh signaling pathway in the treatment, prognosis, and prevention of CRC.

Effect of mTHPC-mediated photodynamic therapy on 5-fluorouracil resistant human colorectal cancer cells

The primary or acquired cancer chemoresistance is a major problem in the treatment of cancer patients. It could be overcome by non-overlapping treatment regimens such as photodynamic therapy (PDT). PDT is based on the oxidation of cellular components which occurs when a light-excited photosensitizer generates reactive oxygen species (ROS). In this study the effect of mTHPC mediated PDT (mTHPC-PDT) on 5-FU resistant colorectal cancer (CRC) cells HCT116 was investigated. The results show that mTHPC-PDT overcomes 5-FU resistance and is effective against chemoresistant colorectal carcinoma cells.

Increased phosphorylation of 4E‑binding protein 1 predicts poor prognosis for patients with colorectal cancer

As demonstrated in previous studies, the phosphorylated form of 4E‑binding protein 1 (p‑4E‑BP1) may be a suitable tumor biomarker. The aim of the current study was to examine the expression status of p‑4E‑BP1 in colorectal cancer (CRC), in order to determine its clinical significance. The present study enrolled 89 patients with CRC that had undergone radical resection. Paired tumor and adjacent normal tissues were evaluated using immunohistochemistry to detect the protein expression of p‑4E‑BP1 and phosphatase and tensin homolog (PTEN). The study identified 53 cases (59.6%) that exhibited moderate or high expression of p‑4E‑BP1 in tumor tissues, compared with little or no expression in the adjacent normal tissues. Conversely, PTEN protein expression was markedly lower in CRC compared with adjacent normal tissues. p‑4E‑BP1 protein upregulation tissues samples was consistent with PTEN downregulation in CRC samples. p‑4E‑BP1 overexpression was predominant in patients with metastasis to the regional lymph nodes. Moderate/high expression of p‑4E‑BP1 protein was significantly associated with adverse overall survival (OS) in patients. Statistical analysis using the Cox proportional hazards model, indicated that p‑4E‑BP1 expression was an independent factor suitable for predicting OS in CRC patients, which was independent of lymph node metastasis. In conclusion, p‑4E‑BP1 protein expression appears to be upregulated in CRC, suggesting that it may be a suitable biomarker for predicting CRC prognosis.

AKT1 has dual actions on the glucocorticoid receptor by cooperating with 14-3-3

Glucocorticoids are important therapeutic compounds for acute lymphoblastic leukemia (ALL). AKT1 or the protein kinase B is frequently activated in ALL, and contributes to the development of glucocorticoid resistance. We examined impact of AKT1 on glucocorticoid receptor (GR)-induced transcriptional activity in cooperation with phospho-serine/threonine-binding protein 14-3-3. AKT1 has two distinct actions on GR transcriptional activity, one through segregation of GR in the cytoplasm by phosphorylating GR at Ser-134 and subsequent association of 14-3-3, and the other through direct modulation of GR transcriptional activity in the nucleus. For the latter, AKT1 and 14-3-3 are attracted to DNA-bound GR, accompanied by AKT1-dependent p300 phosphorylation, H3S10 phosphorylation and H3K14 acetylation at the DNA site. These two actions of AKT1 regulate distinct sets of glucocorticoid-responsive genes. Our results suggest that specific inhibition of the AKT1/14-3-3 activity on the cytoplasmic retention of GR may be a promising target for treating glucocorticoid resistance observed in ALL.

microRNA-342-5p and miR-608 inhibit colon cancer tumorigenesis by targeting NAA10

miRNAs have been shown to play pivotal roles in the establishment and progression of colon cancer, but their underlying mechanisms are not fully understood. N-acetyltransferase NAA10 participates in many cellular processes, including tumorigenesis. Here we showed that miR-342-5p and miR-608 suppressed the tumorigenesis of colon cancer cells in vitro and in vivo by targeting NAA10 mRNA for degradation. Overexpression of miR-342-5p or miR-608 decreased NAA10 mRNA and protein levels and thereby suppressed cell proliferation, migration, and cell-cycle progression, as well as promoted apoptosis in SW480 and SW620 cells. More importantly, miR-342-5p and miR-608 significantly decreased the tumorigenic capacity of SW480 and SW620 cells in a mouse xenograft model. We also observed an inverse correlation between the expression of NAA10 and that of both miRNAs. Our results implicate miR-342-5p and miR-608 in colon cancer development and unveil the underlying mechanism of this phenomenon, which involves NAA10.

Inhibition of cell proliferation and tumor growth of colorectal cancer by inhibitors of Wnt and Notch signaling pathways

Understanding the role and mechanism of signaling pathways including Notch and Wnt in colorectal carcinogenesis is critical to the development of novel therapeutics. In the present study, we analyzed the cell proliferation, migration, G2/M percentage and the expression of molecules of signaling pathways in HCT-116 cells through the inhibition of Wnt and Notch pathways, and also investigated the effect of inhibitors of Wnt and Notch pathways on tumor growth in a transplantation tumor model. We observed that rDDK-1 (an inhibitor of the Wnt signaling pathway) and LY374973 (an inhibitor of the Notch signaling pathway) synergistically inhibited the proliferation, migration and G2/M percentage of HCT-116 cell lines, and could further synergistically inhibit the tumor volume and weight in the transplantation tumor model. In the cell line and the transplantation tumor model, rDDK-1 and LY374973 further synergistically inhibited the expression level of all detected Wnt and Notch pathway genes. Our results may pave the way for using inhibitors of Wnt and Notch signaling pathways together to treat colorectal cancer.

Anastomotic recurrence of colon cancer: Genetic analysis challenges the widely held theories of cancerous cells' intraluminal implantation and metachronous carcinogenesis

BACKGROUND AND OBJECTIVES

Anastomotic recurrence (AR), whose etiopathogenesis is attributed to intraluminal implantation of cancerous cells or metachronous carcinogenesis, is a major issue for patients undergoing colon cancer (CC) resection. The objective of the study is to throw some light on AR etiopathogenesis and to identify risk factors of AR in selecting patients to undergo early endoscopy.

METHODS

An analysis of clinical and histopathological parameters, including MSI and LOH of seven sites (Myc-L, BAT26, BAT40, D5S346, D18S452, D18S64, D16S402) was performed in primary CC and AR of 18 patients. They were then compared to 36 controls not developing AR.

RESULTS

A genetic instability was present in 16/18 patients, with distinct genetic patterns between primaries and ARs. LOH at 5q21 and/or 18p11.23 were found in both primary and AR in >50% of cases, but this rate was no different from control population. CEA resulted as associated with AR (P = 0.03), whereas N status presented a borderline result (P = 0.08).

CONCLUSIONS

Our findings challenge present theories about AR development. No "genetic marker" has been found. CEA and, to a lesser extent, N status, appear associated with AR. Rectal washout is seemingly meaningless. Iterative resection should be recommended since a long survival may be expected. J. Surg. Oncol. 2016;114:228-236. © 2016 Wiley Periodicals, Inc.

Overexpression of GRO-β is associated with an unfavorable outcome in colorectal cancer

Growth-related oncogene (GRO)-β, or chemokine (C-X-C motif) ligand 2 (CXCL2), is a member of the CXC chemokine family that may mediate various functions, including attracting neutrophils to sites of inflammation, and participating in tumorigenesis and progression. However, the expression of GRO-β in colorectal cancer (CRC) and the association with the clinical outcome of the disease remains poorly understood. In the present study, CXCL2 mRNA expression in CRC was analyzed using six independent datasets from the Oncomine microarray database. The immunohistochemical analysis of tissue microarrays (TMA) was used to characterize the expression of the GRO-β protein in CRC. The association between GRO-β expression and the clinicopathological features and prognosis of patients was determined by statistical analysis. The results indicated that GRO-β was highly expressed in CRC tissues, and that high GRO-β cytoplasmic expression was associated with the tumor location, extent of the primary tumor, and lymph node metastasis. Kaplan-Meier survival and Cox regression analysis revealed that high GRO-β expression was an independent indicator of poor prognosis for CRC patients. The results indicate that high GRO-β expression in CRC may correlate with an unfavorable outcome and facilitate cancer cell invasion and metastasis.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Activin and TGFβ use diverging mitogenic signaling in advanced colon cancer

Background

Understanding cell signaling pathways that contribute to metastatic colon cancer is critical to risk stratification in the era of personalized therapeutics. Here, we dissect the unique involvement of mitogenic pathways in a TGFβ or activin-induced metastatic phenotype of colon cancer.

Method

Mitogenic signaling/growth factor receptor status and p21 localization were correlated in primary colon cancers and intestinal tumors from either AOM/DSS treated ACVR2A (activin receptor 2) −/− or wild type mice. Colon cancer cell lines (+/− SMAD4) were interrogated for ligand-induced PI3K and MEK/ERK pathway activation and downstream protein/phospho-isoform expression/association after knockdown and pharmacologic inhibition of pathway members. EMT was assessed using epithelial/mesenchymal markers and migration assays.

Results

In primary colon cancers, loss of nuclear p21 correlated with upstream activation of activin/PI3K while nuclear p21 expression was associated with TGFβ/MEK/ERK pathway activation. Activin, but not TGFβ, led to PI3K activation via interaction of ACVR1B and p85 independent of SMAD4, resulting in p21 downregulation. In contrast, TGFβ increased p21 via MEK/ERK pathway through a SMAD4-dependent mechanism. While activin induced EMT via PI3K, TGFβ induced EMT via MEK/ERK activation. In vivo, loss of ACVR2A resulted in loss of pAkt, consistent with activin-dependent PI3K signaling.

Conclusion

Although activin and TGFβ share growth suppressive SMAD signaling in colon cancer, they diverge in their SMAD4-independent pro-migratory signaling utilizing distinct mitogenic signaling pathways that affect EMT. p21 localization in colon cancer may determine a dominant activin versus TGFβ ligand signaling phenotype warranting further validation as a therapeutic biomarker prior to targeting TGFβ family receptors.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0456-4) contains supplementary material, which is available to authorized users.

Functional characterization of the nitrogen permease regulator-like-2 candidate tumor suppressor gene in colorectal cancer cell lines

The nitrogen permease regulator‑like‑2 (NPRL2) gene is a candidate tumor suppressor gene, which has been identified in the 3p21.3 human chromosome region. Decreased expression levels of NPRL2 have been observed in colorectal cancer (CRC) tissues, however, the function of NPRL2 in CRC progression remains to be fully elucidated. The present study investigated the biological characteristics of the HCT116 and HT29 CRC cell lines overexpressing exogenous NPRL2. NPRL2 recombinant lentiviral vectors were also constructed and transfected in the present study. Cell growth was determined using a Cell Counting Kit‑8 assay and a colony formation assay. The cell cycle and rate of apoptosis were assessed using flow cytometric analysis. Transwell assays were used to evaluate cell invasion. The protein expression of phosphorylated (p)‑AKT and caspase 3, B‑cell lymphoma 2 (Bcl2) and Bcl‑2‑associated X protein apoptosis‑associated genes, were detected using western blotting. The results revealed that NPRL2 overexpression inhibited cell growth, induced cell cycle G1 phase arrest, promoted apoptosis and inhibited invasion in the two human CRC cell lines. Furthermore, the protein expression levels of p‑AKT and Bcl2 were significantly reduced in the NPRL2‑transfected HCT116 and HT29 cells, compared with the mock‑transfected group and control group, while the protein expression of caspase‑3 was increased. Therefore, NPRL2 acted as a functional tumor suppressor in the CRC cell lines.

Growth-factor dependent expression of the translationally controlled tumour protein TCTP is regulated through the PI3-K/Akt/mTORC1 signalling pathway

Translationally controlled tumour protein TCTP (gene symbol: TPT1) is a highly-conserved, cyto-protective protein implicated in many physiological and disease processes, in particular cancer, where it is associated with poor patient outcomes. To understand the mechanisms underlying the accumulation of high TCTP levels in cancer cells, we studied the signalling pathways that control translation of TCTP mRNA, which contains a 5'-terminal oligopyrimidine tract (5'-TOP). In HT29 colon cancer cells and in HeLa cells, serum increases the expression of TCTP two- and four-fold, respectively, and this is inhibited by rapamycin or mTOR kinase inhibitors. Polysome profiling and mRNA quantification indicate that these effects occur at the level of mRNA translation. Blocking this pathway upstream of mTOR complex 1 (mTORC1) by inhibiting Akt also prevented increases in TCTP levels in both HeLa and HT29 colon cancer cells, whereas knockout of TSC2, a negative regulator of mTORC1, led to derepression of TCTP synthesis under serum starvation. Overexpression of eIF4E enhanced the polysomal association of the TCTP mRNA, although it did not protect its translation from inhibition by rapamycin. Conversely, expression of a constitutively-active mutant of the eIF4E inhibitor 4E-BP1, which is normally inactivated by mTORC1, inhibited TCTP mRNA translation in HEK293 cells. Our results demonstrate that TCTP mRNA translation is regulated by signalling through the PI3-K/Akt/mTORC1 pathway. This explains why TCTP levels are frequently increased in cancers, since mTORC1 signalling is hyperactive in ~80% of tumours.

Molecular mechanisms associated with PTHrP-induced proliferation of colon cancer cells

Parathyroid Hormone-related Protein (PTHrP) is normally produced in many tissues and is recognized for its endocrine, paracrine, autocrine and intracrine modes of action. PTHrP is also implicated in different types of cancer and its expression correlates with the severity of colon carcinoma. Using the human colon cell line Caco-2 we recently obtained evidence that PTHrP, through a paracrine pathway, exerts a protective effect under apoptotic conditions. However, if exogenous PTHrP is able or not to induce the proliferation of these intestinal tumor cells is not known. We found that PTHrP treatment increases the number of live Caco-2 cells. The hormone induces the phosphorylation and nuclear translocation of ERK 1/2, α p38 MAPK, and Akt, without affecting JNK phosphorylation. In addition, PTHrP-dependent ERK phosphorylation is reverted when PI3K activity was inhibited. Following MAPKs nuclear translocation, the transcription factors ATF-1 and CREB were activated in a biphasic manner. In addition PTHrP induces the translocation into the nucleus of β-catenin, protein that plays key role in maintaining the growth and proliferation of colorectal cancer, and increases the amount of both positive cell cycle regulators c-Myc and Cyclin D. Studies with ERK1/2, α p38 MAPK, and PI3K specific inhibitors showed that PTHrP regulates Caco-2 cell proliferation via these signaling pathways. In conclusion, the results obtained in this work expand our knowledge on the role of exogenous PTHrP in intestinal tumor cells and identify the signaling pathways that are involved in the mitogenic effect of the hormone on Caco-2 cells.

Peroxisome proliferator-activated receptor-γ is downregulated in ulcerative colitis and is involved in experimental colitis-associated neoplasia

The aim of the present study was to evaluate the expression of peroxisome proliferator-activated receptor (PPAR)-γ in inflammatory bowel disease (IBD), and to also identify the association between PPAR-γ and the clinical features of patients with IBD. An azoxymethane (AOM)/dextran sodium sulfate (DSS) animal model of colitis-associated neoplasia was established to investigate the protective effect of 5-aminosalicylic acid (5-ASA) and to explore the changes in the expression of PPAR-γ during this process. A total of 66 specimens of colorectal tissue obtained from biopsy performed on IBD patients and 30 healthy control individuals were immunohistochemically stained for PPAR-γ. An AOM/DSS animal model of colitis-associated neoplasia was then established. Reverse transcription quantitative polymerase chain reaction was conducted and it was found that, compared with the control group and patients with Crohn's disease (CD), the expression of PPAR-γ in the intestinal tissue of patients with ulcerative colitis (UC) was significantly decreased (P=0.027 and 0.046, respectively). The expression of PPAR-γ was found to be negatively associated with the disease activity of UC and was not associated with the severity of disease, site of lesions or CD characteristics. Administration of 5-ASA decreased the colitis and tumor burden of colons. The expression level of PPAR-γ in the intestinal tissue was also increased in the AOM/DSS/5-ASA group compared with AOM/DSS group (P<0.001). PPAR-γ is an important factor in the pathogenesis of UC and colitis-associated cancer. The present study found that 5-ASA significantly alleviates the colitis and tumor burden in a mouse model of AOM/DSS-induced colitis-associated neoplasia, and promotes the expression of PPAR-γ in the intestinal tract.

Mode and specificity of binding of the small molecule GANT61 to GLI determines inhibition of GLI-DNA binding

The GLI genes, GLI1 and GLI2, are transcription factors that regulate target genes at the distal end of the canonical Hedgehog (HH) signaling pathway (SHH->PTCH->SMO->GLI), tightly regulated in embryonic development, tissue patterning and differentiation. Both GLI1 and GLI2 are oncogenes, constitutively activated in many types of human cancers. In colon cancer cells oncogenic KRAS-GLI signaling circumvents the HH-SMO-GLI axis to channel through and activate GLI in the transcriptional regulation of target genes. We have observed extensive cell death in a panel of 7 human colon carcinoma cell lines using the small molecule GLI inhibitor GANT61. Using computational docking and experimental confirmation by Surface Plasmon Resonance, GANT61 binds to the 5-zinc finger GLI1 protein between zinc fingers 2 and 3 at sites E119 and E167, independent of the GLI-DNA binding region, and conserved between GLI1 and GLI2. GANT61 does not bind to other zinc finger transcription factors (KLF4, TFIIβ). Mutating the predicted GANT61 binding sites in GLI1 significantly inhibits GANT61-GLI binding and GLI-luciferase activity. Data establish the specificity of GANT61 for targeting GLI, and substantiate the critical role of GLI in cancer cell survival. Thus, targeting GLI in cancer therapeutics may be of high impact.

Biology of colorectal cancer

Colorectal cancer is a serious health problem, a challenge for research, and a model for studying the molecular mechanisms involved in its development. According to its incidence, this pathology manifests itself in three forms: family, hereditary, and most commonly sporadic, apparently not associated with any hereditary or familial factor. For the types having inheritance patterns and a family predisposition, the tumours develop through defined stages ranging from adenomatous lesions to the manifestation of a malignant tumour. It has been established that environmental and hereditary factors contribute to the development of colorectal cancer, as indicated by the accumulation of mutations in oncogenes, genes which suppress and repair DNA, signaling the existence of various pathways through which the appearance of tumours may occur. In the case of the suppressive and mutating tracks, these are characterised by genetic disorders related to the phenotypical changes of the morphological progression sequence in the adenoma/carcinoma. Moreover, alternate pathways through mutation in BRAF and KRAS genes are associated with the progression of polyps to cancer. This review surveys the research done at the cellular and molecular level aimed at finding specific alternative therapeutic targets for fighting colorectal cancer.

Effect of hierarchical psychological nursing on negative emotions and hope in colorectal cancer patients undergoing surgery

AIM: To explore the effect of hierarchical psychological nursing on negative emotions and hope in colorectal cancer patients undergoing surgery.

METHODS: Eighty colorectal cancer patients undergoing surgery from June 2012 to June 2014 were selected as an observation group, and 80 colorectal cancer patients undergoing operation from June 2010 and May 2012 comprised a control group. Patients in the control group were given conventional nursing, while the observation group was given hierarchical psychological nursing on the basis of conventional nursing. The scores of self-rating anxiety scale (SAS), self-rating depression scale (SDS), the Herth hope index (HHI), and nursing job satisfaction scale were compared between the two groups at admission and discharge. The length of hospital stay and total medical costs were also compared.

RESULTS: At the time of discharge, the scores of SAS and SDS in the observation group were significantly lower than those in the control group (P < 0.001). The total score and scores of every dimension of HHI and the score of nursing job satisfaction scale in the observation group were significantly higher than those in the control group (P < 0.05). The length of hospital stay and total medical costs in the observation group were significantly lower than those in the control group (P < 0.001).

CONCLUSION: Hierarchical psychological nursing could significantly reduce the negative emotions and improve hope levels in colorectal cancer patients undergoing surgery, thereby promoting rehabilitation and improving the quality of nursing.

MicroRNA-17-5p promotes chemotherapeutic drug resistance and tumour metastasis of colorectal cancer by repressing PTEN expression

Background: Colorectal cancer (CRC) is one of the most common cancers worldwide, especially in Western countries. Although chemotherapy is used as an adjuvant or as a palliative treatment, drug resistance poses a great challenge. This study intended to identify biomarkers as predictive factors for chemotherapy.

Patients and methods: By microarray analysis, we studied miRNAs expression profiles in CRC patient, comparing chemoresistant and chemosensitive groups. The miRNAs of interest were validated and the impact on clinical outcomes was assessed in a cohort of 295 patients. To search for potential targets of these miRNAs, tissue samples were subject to in situ hybridization and immunohistochemistry analysis. Colorectal adenocarcinoma cells were also used for in vitro experimentation, where cellular invasiveness and drug resistance were examined in miRNA-transfected cells.

Results: The expression level of miRNA-17-5p was found increased in chemoresistant patients. Significantly higher expression levels of miR-17-5p were found in CRC patients with distant metastases and higher clinical stages. Kaplan-Meier analysis showed that CRC patients with higher levels of miR-17-5p had reduced survival, especially in patients who had previously received chemotherapy. Overexpression of miR-17-5p promoted COLO205 cell invasiveness. We found that PTEN was a target of miR-17-5p in the colon cancer cells, and their context-specific interactions were responsible for multiple drug-resistance. Chemotherapy was found to increase the expression levels of miR-17-5p, which further repressed PTEN levels, contributing to the development of chemo-resistance.

Conclusions: MiR-17-5p is a predictive factor for chemotherapy response and a prognostic factor for overall survival in CRC, which is due to its regulation of PTEN expression.