Colon cancer: genomics and apoptotic events

Integrative analysis and risk model construction for super‑enhancer‑related immune genes in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer associated with poor prognosis, and accounts for the majority of RCC-related deaths. The lack of comprehensive diagnostic and prognostic biomarkers has limited further understanding of the pathophysiology of ccRCC. Super-enhancers (SEs) are congregated enhancer clusters that have a key role in tumor processes such as epithelial-mesenchymal transition, metabolic reprogramming, immune escape and resistance to apoptosis. RCC may also be immunogenic and sensitive to immunotherapy. In the present study, an Arraystar human SE-long non-coding RNA (lncRNA) microarray was first employed to profile the differentially expressed SE-lncRNAs and mRNAs in 5 paired ccRCC and peritumoral tissues and to identify SE-related genes. The overlap of these genes with immune genes was then determined to identify SE-related immune genes. A model for predicting clinical prognosis and response to immunotherapy was built following the comprehensive analysis of a ccRCC gene expression dataset from The Cancer Genome Atlas (TCGA) database. The patients from TCGA were divided into high- and low-risk groups based on the median score derived from the risk model, and the Kaplan-Meier survival analysis showed that the low-risk group had a higher survival probability. In addition, according to the receiver operating characteristic curve analysis, the risk model had more advantages than other clinical factors in predicting the overall survival (OS) rate of patients with ccRCC. Using this model, it was demonstrated that the high-risk group had a more robust immune response. Furthermore, 61 potential drugs with half-maximal inhibitory concentration values that differed significantly between the two patient groups were screened to investigate potential drug treatment of ccRCC. In summary, the present study provided a novel index for predicting the survival probability of patients with ccRCC and may provide some insights into the mechanisms through which SE-related immune genes influence the diagnosis, prognosis and potential treatment drugs of ccRCC.

Induction of G0/G1 phase cell cycle arrest and apoptosis by thymol through ROS generation and caspase-9/-3 activation in breast and colorectal cancer cell lines

BACKGROUND

Cancer is a major malignancy and one of the leading causes of death; it calls for a proactive strategy for the cure. Herbs are reservoirs of novel chemical entities and their phytochemical exploration has contributed considerably to the discovery of new anticancer drugs. Thymol, a natural phenolic monoterpenoid, has been implicated with many medicinal properties, including anticancer ones. However, the anti-proliferative and apoptosis-inducing ability of thymol on MDA-MB-231 and HCT-8 cell lines has not been studied yet in detail, and hence this study was conceived.

MATERIALS AND METHODS

We studied the cytotoxicity, morphological alterations of the cell, oxidative stress, cell cycle modulation, apoptosis and expression of apoptosis-related proteins that ensued due to thymol treatment in these cancer cells.

RESULTS

Thymol inhibited the cell proliferation, altered the morphology of the cells, increased the intracellular ROS level, arrested the cells in G0/G1 phase, induced apoptosis, upregulated pro-apoptotic protein p53 expression, downregulated anti-apoptotic protein Bcl-xL expression, and activated caspase-9 and -3.

CONCLUSION

These findings elucidate that thymol induces apoptosis through the intrinsic pathway, in MDA-MB-231 breast and HCT-8 colorectal cancer cells through ROS generation and G0/G1 phase cell cycle arrest. This reiterates the broad-spectrum anti-tumor potential of thymol and provides an insight to study further to be developed into an anticancer drug.

A possible genetic association between obesity and colon cancer in females

Object

There is mounting clinical evidence that an increase in obesity is linked to an increase in cancer incidence and mortality. Although studies have shown a link between obesity and colon cancer, the particular mechanism of the interaction between obesity and colon cancer in females remains unknown. The goal of this work is to use bioinformatics to elucidate the genetic link between obesity and colon cancer in females and to investigate probable molecular mechanisms.

Methods

GSE44076 and GSE199063 microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. In the two microarray datasets and healthy controls, the online tool GEO2R was utilized to investigate the differential genes between obesity and colon cancer. The differential genes (DEGs) identified in the two investigations were combined. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment studies were performed on the DEGs. The STRING database and Cytoscape software were then used to build protein-protein interaction (PPI) networks to discover hub genes. NetworkAnalyst was also used to build networks of target microRNAs (miRNAs) and hub genes, as well as networks of transcriptions.

Results

Between the two datasets, 146 DEGs were shared. The DEGs are primarily enriched in inflammatory and immune-related pathways, according to GO analysis and KEGG. 14 hub genes were identified via PPI building using the Cytoscape software's MCODE and CytoNCA plug-ins: TYROBP, CD44, BGN, FCGR3A, CD53, CXCR4, FN1, SPP1, IGF1, CCND1, MMP9, IL2RG, IL6 and CTGF. Key transcription factors for these hub genes include WRNIP1, ATF1, CBFB, and NR2F6. Key miRNAs for these hub genes include hsa-mir-1-3p, hsa-mir-26b-5p, hsa-mir-164a-5p and hsa-mir-9-5p.

Conclusion

Our research provides evidence that changed genes are shared by female patients with colon cancer and obesity. Through pathways connected to inflammation and the immune system, these genes play significant roles in the emergence of both diseases. We created a network between hub genes and miRNAs that target transcription factors, which may offer suggestions for future research in this area.

Effective prediction of potential ferroptosis critical genes in clinical colorectal cancer

BACKGROUND

Colon cancer is common worldwide, with high morbidity and poor prognosis. Ferroptosis is a novel form of cell death driven by the accumulation of iron-dependent lipid peroxides, which differs from other programmed cell death mechanisms. Programmed cell death is a cancer hallmark, and ferroptosis is known to participate in various cancers, including colon cancer. Novel ferroptosis markers and targeted colon cancer therapies are urgently needed. To this end, we performed a preliminary exploration of ferroptosis-related genes in colon cancer to enable new treatment strategies.

METHODS

Ferroptosis-related genes in colon cancer were obtained by data mining and screening for differentially expressed genes (DEGs) using bioinformatics analysis tools. We normalized the data across four independent datasets and a ferroptosis-specific database. Identified genes were validated by immunohistochemical analysis of pathological and healthy clinical samples.

RESULTS

We identified DEGs in colon cancer that are involved in ferroptosis. Among these, five core genes were found: ELAVL1, GPX2, EPAS1, SLC7A5, and HMGB1. Bioinformatics analyses revealed that the expression of all five genes, except for EPAS1, was higher in tumor tissues than in healthy tissues.

CONCLUSIONS

The preliminary exploration of the five core genes revealed that they are differentially expressed in colon cancer, playing an essential role in ferroptosis. This study provides a foundation for subsequent research on ferroptosis in colon cancer.

Identification and Validation of a Novel Prognostic Gene Model for Colorectal Cancer

Aims

Colon cancer (CRC), with high morbidity and mortality, is a common and highly malignant cancer, which always has a bad prognosis. So it is urgent to employ a reasonable manner to assess the prognosis of patients. We developed and validated a gene model for predicting CRC risk.

Methods

The Gene Expression Omnibus (GEO) database was used to extract the gene expression profiles of CRC patients (N = 181) from GEO to identify genes that were differentially expressed between CRC patients and controls and then stable signature genes by firstly using both robust likelihood-based modeling with 1000 iterations and random survival forest variable hunting algorithms. Cluster analysis using the longest distance method was drawn out, and Kaplan–Meier (KM) survival analysis was used to compare the clusters. Meanwhile, the risk score was evaluated in three independent datasets including the GEO and Illumina HiSeq sequencing platforms. The corresponding risk index was calculated, and samples were clustered into high- and low-risk groups according to the median. And survival ROC analysis was used to evaluate the prognostic model. Finally, the Gene Set Enrichment Analysis (GSEA) was performed for further functional enrichment analyses.

Results

A 10-gene model was obtained, including 7 negative impact factors (SLC39A14, AACS, ERP29, LAMP3, TMEM106C, TMED2, and SLC25A3) and 3 positive ones (CNPY2, GRB10, and PBK), which related with several important oncogenic pathways (KRAS signaling, TNF-α signaling pathway, and WNT signaling pathway) and several cancer-related cellular processes (epithelial mesenchymal transition and cellular apoptosis). By using colon cancer datasets from The Cancer Genome Atlas (TCGA), the model was validated in KM survival analysis (P ≤ 0.001) and significant analysis with recurrence time (P = 0.0018).

Conclusions

This study firstly developed a stable and effective 10-gene model by using novel combined methods, and CRC patients might be able to use it as a prognostic marker for predicting their survival and monitoring their long-term treatment.

GINS2 regulates the proliferation and apoptosis of colon cancer cells through PTP4A1

Colon cancer is associated with high death rates worldwide and poses a serious threat to public health. GINS complex subunit 2 (GINS2) serves a carcinogenic role in many cancers, including gastric adenocarcinoma, ovarian cancer and pancreatic cancer. However, the specific function of GINS2 in the development of colon cancer has not been described in detail. The present study aimed to clarify the role of GINS2 in colon cancer. A Cell Counting Kit‑8 assay, EdU staining, TUNEL and flow cytometry analyses were performed to determine the levels of cell viability, proliferation and apoptosis and to evaluate the cell cycle. Through the analysis of BioGrid, a Protein‑Protein Interaction database, it was hypothesized that protein tyrosine phosphatase 4A1 (PTP4A1) is a protein that might interact with GINS2, which was then validated using a co‑immunoprecipitation assay. mRNA and protein levels were measured using reverse transcription‑quantitative PCR and western blotting, respectively. The results of the present study demonstrated that GINS2 expression levels were increased in colon cancer cells. Furthermore, GINS2 knockdown inhibited the proliferation of colon cancer cells, while the levels of cell cycle arrest and apoptosis were increased. By interacting with PTP4A1, GINS2 promoted the expression of PTP4A1, a novel p53 target. GINS2 knockdown was increased, while PTP4A1 overexpression decreased the protein level of p53. Notably, PTP4A1 overexpression partly reversed the effects of GINS2 downregulation on colon cancer cells. Therefore, the present study demonstrated that GINS2 regulated the proliferation and apoptosis of colon cancer cells through PTP4A1/p53 pathway, highlighting that GINS2 may serve as a novel molecular marker for colon cancer prevention and therapy.

Colorectal Carcinoma Growth Inhibition by Dietary Care Combined with Probiotic Intervention through Targeting NRP2 Expression

The present study investigated the effect of probiotics on inhibition of colorectal tumor growth in vivo and as anti-proliferative agent in vitro. Viability changes were measured by MTT assay whereas protein expression was assessed using western blotting. The study demonstrated that tumor growth was delayed significantly (P < 0.05) in probiotic administered mice from 2nd week compared to the control group. The difference in body weight of the mice in probiotic administered, 5-fluorouracil treated and untreated groups of the mice showed no significant differences during 5-weeks of the study. In probiotic administered mice the expression of miR-331-3p was significantly promoted and that of NRP2 effectively alleviated. Probiotic administration of the mice led to a significant (P < 0.05) increase in p53 and p-c-Jun expression and reduction in Bcl-2 level. Probiotic treatment of SW480 and HCT116 cells led to a significant (P < 0.05) reduction in viability after 48 h compared to the control cells. However, no changes were observed in FHC cell viability after 48 h of treatment with probiotics. The expression of miR-331-3p in SW480 and HCT116 cells was significantly promoted on treatment with probiotics after 48 h. Additionally, probiotic treatment for 48 h led to a remarkable reduction in NRP2 expression in SW480 and HCT116 cells. Thus, probiotic administration inhibited colorectal tumor growth in vivo in mice possibly by upregulation of miR-331-3p expression and down-regulation of NRP2 level. Therefore, probiotics may be used for the treatment of colorectal cancer growth.

Downregulation of SUN2 promotes metastasis of colon cancer by activating BDNF/TrkB signalling by interacting with SIRT1

Distant metastasis is the major cause of colon cancer (CC) treatment failure. SAD1/UNC84 domain protein-2 (SUN2) is a key component of linker of the nucleoskeleton and cytoskeleton (LINC) complexes that may be relevant for metastasis in several cancers. Here, we first confirmed that SUN2 levels were significantly lower in primary CC tissues and distant metastasis than in normal colon tissues, and high SUN2 expression predicted good overall survival. Overexpression of SUN2 or knockdown of SUN2 inhibited or promoted cell migration and invasion in vitro, respectively. Moreover, silencing of SUN2 promoted metastasis in vivo. Mechanistically, we showed that SUN2 exerts its tumour suppressor functions by decreasing the expression of brain derived neurotrophic factor (BDNF) to inhibit BDNF/tropomyosin-related kinase B (TrkB) signalling. Additionally, SUN2 associated with SIRT1 and increased the acetylation of methyl-CpG binding protein 2 (MeCP2) to increase its occupancy at the BDNF promoter. Taken together, our findings indicate that SUN2 is a key component in CC progression that acts by inhibiting metastasis and that novel SUN2-SIRT1-MeCP2-BDNF signalling may prove to be useful for the development of new strategies for treating patients with CC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Andiroba oil and nanoemulsion (Carapa guianensis Aublet) reduce lesion severity caused by the antineoplastic agent doxorubicin in mice

Doxorubicin (DOX) is an anthracycline antibiotic used in the fight against many types of cancer. Although it is quite effective for this purpose, its clinical use is limited by its severe side effects, highlighting the relevance of efforts to identify substances that act to minimize these effects. In this work, we sought to verify the ability of andiroba oil (AO) and a nanoemulsion of andiroba oil (AN) to lessen the side effects of DOX. The animals were separated into 7 groups with 6 animals each: mice treated with AO (2000 mg/kg), AN (2000 mg/kg), the antineoplastic agent DOX (40 mg/kg), AO+DOX, AN+DOX and solvent controls was used of negative control (corn oil and nanoemulsion surfactant). AO and AN were administered for 14 consecutive days orally by gavage and on the 13th day, applied DOX by intraperitoneal route (i.p.), in order to evaluate the protective potential of andiroba. The animals were euthanized on the 15th day. Hematological, biochemical, histological, and immunohistochemical parameters were analyzed. Andiroba reduced several aspects of the severity of lesions caused by DOX, decreasing hematotoxicity and the severity of histological changes in the liver and kidneys, and reducing the frequency of apoptotic cell death. In many cases, AN showed greater efficacy than AO alone, reflecting the feasibility of using this nanotechnology to improve the pharmacokinetics of lipid compounds in the body. The study sheds new light on the therapeutic benefits of andiroba and suggests new ways for investigating how the quantity and quality of lipid compounds affect exposed organisms.

Syntaxin 2 promotes colorectal cancer growth by increasing the secretion of exosomes

Background: Colorectal cancer (CRC) is one of the most common cancers with high mortality worldwide. Uncontrolled growth is an important hallmark of CRC. However, the mechanisms are poorly understood. Methods: Syntaxin 2 (STX2) expression was analyzed in 160 cases of paraffin-embedded CRC tissue by immunohistochemistry, in 10 cases of fresh CRC tissue by western blot, and in 2 public databases. Gain- and loss-of-function analyses were used to investigate the biological function of STX2 in CRC growth. Exosomes isolation, characterization, Co-immunoprecipitation (Co-IP), flow cytometry and fluorescence were conducted to study the molecular mechanism of STX2 in CRC growth. Results: The expression of STX2 was obviously up-regulated in human CRC tissues. Overexpression of STX2 increased the growth of CRC cells in vitro and in vivo. Downregulation of STX2 repressed the growth of CRC. STX2 modulated exosomes secretion of CRC cells which might correlated with Rab8a expression. The secreted exosomes could be ingested by CRC cells, and ultimately promoted the growth of CRC by arresting the tumor cells at S phase. Conclusions: Our data provide evidence that STX2 promotes CRC growth by increasing exosomes secretion of CRC cells; And the modulation of STX2 in exosomes secretion correlates with Rab8a. Thus, our study identified a new mechanism of STX2 in CRC growth and may provide a possible strategy for CRC therapy.

Identification of Transcription Factor/Gene Axis in Colon Cancer Using a Methylome Approach

Colon cancer is one of the most commonly diagnosed cancers worldwide. Both environmental and molecular characters can influence its development. DNA methylation has been heralded as a promising marker for use in cancer prevention, diagnosis, and treatment. It has been shown to facilitate cancer progression through multiple mechanisms. Changes in DNA methylation can inhibit or promote the binding of transcription factors (TFs) and further disturb gene regulation. Detection of DNA methylation-mediated regulatory events in colon cancer are critical for mining novel biomarkers. Here, we explore the influence of CpG sites located at promoter regions of differentially expressed genes and identify methylation–gene relationships using expression–methylation quantitative trait loci. We find that promoter methylation sites mainly negatively regulate the corresponding genes. We also identify candidate TFs that can bind to these sites in a sequence-dependent manner. By integrating transcriptome and methylome profiles, we construct a TF–CpG–gene regulatory network for colon cancer, which is used to determine the roles of TFs and methylation in the transcription process. Finally, based on TF–CpG–gene relationships, we design a framework to evaluate patient prognosis, which shows that one TF–CpG–gene triplet is significantly associated with patient survival rate and represents a potential novel biomarker for use in colon cancer prognosis and treatment.

Integrin Subunit Alpha 5 (ITGA5) Gene Circular RNA Sponges microRNA-107 in Colorectal Carcinoma Cells and Tissues and Regulates the Expression of the Forkhead Box J3 (FOXJ3) Gene

Background

Circular RNAs (circRNAs) can function as sponges for microRNA (miRNA) in carcinogenesis. This study aimed to investigate the role of the circRNA of the integrin subunit alpha 5 (ITGA5) gene and microRNA-107 (miR-107) in human colorectal carcinoma (CRC) cells in vitro and tissue samples from patients with CRC and the expression of forkhead box J3 (FOXJ3) protein.

Material/Methods

Thirty paired CRC tissue samples and adjacent normal colon tissue samples were studied. Human CRC cell lines, including HT29, SW480, LoVo, and HIEC cells, were studied for cell proliferation using the cell counting kit-8 (CCK-8) assay. Cell migration was studied using a transwell assay, and cell apoptosis was determined using flow cytometry. The luciferase reporter assay was used to study the interactions between ITGA5 circRNA, FOXJ3, and miR-107 in human CRC cells. The expression of ITGA5 circRNA and miR-107 was determined using quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of FOXJ3 were measured by Western blot.

Results

The expression of ITGA5 circRNA was significantly reduced in CRC tissues and CRC cell lines. High ITGA5 circRNA expression inhibited the proliferation and cell migration of CRC cells and promoted the apoptosis of CRC cells. The luciferase reporter assay confirmed that ITGA5 circRNA bound to miR-107, which directly targeted FOXJ3.

Conclusions

ITGA5 circRNA may act as a sponge for miR-107 to upregulate FOXJ3 expression and act as a tumor suppressor in CRC cells.

An Overview of Recent Advances in Biological and Pharmaceutical Developments of Fluoro-containing Drugs

:

This review article provides a brief assessment of the biological and pharmaceutical developments of fluorinated drugs. It also discusses possible impacts on the further development of new fluoro-containing pharmaceuticals. Structural aspects of new drug-candidates currently under development and their biological properties, therapeutic potential and syntheses are critically evaluated

circIFT80 Functions as a ceRNA of miR-1236-3p to Promote Colorectal Cancer Progression

Circular RNAs (circRNAs), a recently identified new member of non-coding RNAs, are demonstrated to participate in diverse biological processes; however, the molecular mechanisms that link circRNAs with colorectal cancer (CRC) are not well understood. In the present study, we attempted to explore the roles of the exosomal circRNAs on CRC progression. We first compared the expression patterns of exosomal circRNAs between the plasma of CRC patients and healthy controls. We identified 448 significantly dysregulated exosomal circRNAs in CRC plasma. We focused on hsa_circ_0067835, which is located on chromosome 3 and derived from IFT80; thus, we named it circIFT80. Then, the expression of circIFT80 was detected in 58 CRC tissues and cell lines by qRT-PCR. Functional assays were performed to evaluate the effects of circIFT80 on tumor growth in vitro and in vivo. The relationship between circIFT80 and miR-1236-3p was confirmed by luciferase reporter assay. We found that circIFT80 was significantly upregulated in CRC serum exosomes, CRC tissues, and CRC cell lines compared with normal control. Silencing circIFT80 suppressed CRC cell growth both in vitro and in vivo. We further demonstrated that circIFT80/miR-1236-3p/HOXB7 axis plays an important role in regulating CRC progression. Dual-luciferase reporter system validated the direct interaction of circIFT80, miR-1236-3p, and HOXB7. Western blot verified that inhibition of circIFT80 decreased HOXB7 expression, while a miR-1236-3p inhibitor attenuated the effect of inhibition of circIFT80. In conclusion, these data suggest that circIFT80 is a central component linking circRNAs to the progression of CRC via a miR-1236-3p/HOXB7 axis.

Docking-based approach for identification of mutations that disrupt binding between Bcl-2 and Bax proteins: Inducing apoptosis in cancer cells

BACKGROUND

Inducing apoptosis in cancer cells is an important step for the successful treatment of cancer patients. Bcl-2 is an antiapoptotic protein which determines apoptosis by interacting with proapoptotic members of the Bcl-2 family. Exome sequencing has identified Bcl-2 and Bax missense mutations in more than 40 cancer types. However, a little information is available about the functional impact of each Bcl-2 and Bax mutation on the pathogenesis of cancer.

METHODS

The mutational data from cancer tissues and cell lines were retrieved from the cBioPortal web resource. The 13 mutated Bcl-2 and wild-type Bax complexes with experimentally verified binding were identified from previous studies wherein, binding for all complexes was reportedly disrupted except one. Several protein-protein docking methods such as ClusPro, HDOCK, PatchDock, FireDock, InterEVDock2 and several mutation prediction methods such as PolyPhen-2, SIFT, and OncoKB have been used to predict the effect of mutation to disrupt the binding between Bcl-2 and Bax. The result obtained was compared with the known experimental data.

RESULTS

The protein-protein docking method, ClusPro, employed in the present study confirmed that the binding affinity of 11 out of 13 complexes decreases. Similarly, binding affinity computed for all the 10 wild-type Bcl-2 and mutated Bax complexes agreed with experimentally verified results.

CONCLUSION

Several methods like PolyPhen-2, SIFT, and OncoKB have been developed to predict cancer-associated or deleterious mutations, but no method is available to predict apoptosis-inducing mutations. Thus, in this study, we have examined the mutations in Bcl-2 and Bax proteins that disrupt their binding, which is crucial for inducing apoptosis to eradicate cancer. This study suggests that protein-protein docking methods can play a significant role in the identification of hotspot mutations in Bcl-2 or Bax that can disrupt their binding with wild-type partner to induce apoptosis in cancer cells.

Inhibition of MALAT1 reduces tumor growth and metastasis and promotes drug sensitivity in colorectal cancer

Human metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA known to be highly expressed in several tumors. In colorectal cancer (CRC), MALAT1 promotes cell proliferation, metastasis, and invasion in vitro and in vivo. This study aimed to investigate the effect of MALAT1 on the proliferation, migration, and drug sensitivity of CRC cells in vitro and in vivo and the mechanisms involved therein. We observed increased expression of MALAT1 in six CRC cell lines compared to that in normal cells, suggesting its involvement in CRC progression. Downregulation of MALAT1 inhibited cell migration and induced apoptosis in vitro and inhibited tumor growth and metastasis in nude mice. Furthermore, MALAT1 silencing downregulated the expression of ATP-binding cassette transporters (ABC), breast cancer resistance protein (BCRP), and multi-drug resistance proteins including MDR1 and MRP1, resulting in decreased resistance of cancer cells to 5-FU. In addition, the metastasis and invasion of HCT-116 and HCT-116/5-FU cells were regulated via targeting miR-20b-5p. Based on these observations, we infer that inhibition of MALAT1 suppressed CRC progression and metastasis and improved the sensitivity of cancer cells to 5-FU. The present study proposes a new direction to investigate the molecular mechanisms underlying the invasion and metastasis of CRC, whereby the interaction between MALAT1 and miR-20b-5p could be a novel therapeutic target for CRC.

GLI1 promotes cancer stemness through intracellular signaling pathway PI3K/Akt/NFκB in colorectal adenocarcinoma

The role of Hedgehog (HH)/ glioma-associated oncogene homolog 1 (GLI1) pathway has been implicated in a variety of cancer entities, and the targeted pathway inhibition mediated by GLI1 is of therapeutic relevance. However, its oncogenicity and cross-talks with other cancer pathways including PI3K/Akt/NFκB, which modulates the HH/GLI1 signal strength, have rarely been explored in colorectal adenocarcinoma. We assessed the expression of GLI1 and its relationship with other cancer stemness genes, cell cycle markers, epithelial-mesenchymal transition (EMT), PI3K/Akt/NFκB signaling pathway genes, and HIF1α in 100 paraffin-embedded colorectal adenocarcinoma tissue samples using immunohistochemistry. We further addressed the effect of GLI1 on EMT, cell cycle, and its putative interaction with the PI3K/Akt/NFκB cascade in colorectal adenocarcinoma cell lines. The expression of GLI1 in colorectal adenocarcinoma tissues was found to correlate with the clinical stages, and distant metastasis. Moreover, GLI1 was found to be an independent predictor of poor overall survival and disease-free survival in colorectal adenocarcinoma. GLI1-expressing cancer cells also expressed their representative cancer stem-like cell (CSC) markers (SOX9 and CD133), as well as HIF1α. GLI1 expression was also strongly linked to EMT-related and PI3K/Akt/NFκB signaling genes. Downregulation of GLI1 by inhibitor treatment in colorectal adenocarcinoma cell lines resulted in reduced expression of CSC markers, cell clonogenicity, S-phase subpopulations, as well as the migration and invasion ability. Importantly, Akt inhibitor Perifosine significantly inhibited the expression of pAkt and GLI1 in colorectal adenocarcinoma cells. Combination of GLI1 inhibitor GANT61 and NFκB p65 inhibitor QZN exhibited much higher inhibition compared to using any of them individually on colorectal adenocarcinoma cells. We suggested that GLI1 may be a novel stem cell marker, and cancer stemness was activated via PI3K/Akt/NFκB pathway. In addition, co-targeting GLI1 and PI3K/Akt/NFκB signaling simultaneously might provide an alternative therapeutic strategy for colorectal adenocarcinoma patients.

The effects of lncRNA MALAT1 on proliferation, invasion and migration in colorectal cancer through regulating SOX9

Background

For the study, we determine the potential biomarkers and uncover the regulatory mechanisms of lncRNA MALAT1 / miR-145 / SOX9 axis on the abilities of cell growth and cell metastasis of colorectal cancer.

Methods

Previously published dataset GSE18105 from GEO database was used for microarray analysis to identify differential-expressed lncRNAs and mRNAs. The miRNA which had targeted relationships with both lncRNA and mRNA was predicted using miRCode and Targetscan. The association between lncRNA and miRNA, miRNA and mRNA was verified using dual-luciferase reporter assay.

Expression levels of lncRNA MALAT1, miR-145 and SOX9 were examined by quantitative RT-PCR analysis. The cell viability of two cancer cell lines was compared by CCK-8 assay. Colony formation was hired to detected cell proliferation. The cell cycle distribution and apoptotic cell rate were conducted by flow cytometry assay. Wound healing as well as transwell assay were compare the cell migration and cell invasion respectively among groups. The effect of MALAT1 on colorectal cancer in vivo was constructed by xenograft model.

Results

Significantly dysregulated lncRNAs and mRNAs were identified by microarray analysis. By experimental verification, MALAT1 and SOX9 were expressed in a high percentage of colorectal cancer tumors and cells, while miR-145 was in a low expression. We also identified miR-145 as a target of MALAT1 and SOX9. MALAT1 played a role in regulating cancer process by functioning as a competing endogenous RNA. Silencing MALAT1 could effectively decrease the expression level of SOX9, thus suppress cell viability and metastasis. Down-regulated MALAT1 could induce resistance of G1 phase in cell cycle, and facilitation of colorectal cancer cell apoptosis. Nude mice injected with cells transfected with si-MALAT1 had smaller tumor on size and weight.

Conclusions

The regulatory function of lncRNA MALAT1 / miR-145 / SOX9 axis was revealed in colorectal cancer based on bioinformatics analysis. LncRNA MALAT1 could facilitate colorectal cancer cell proliferation, invasion and migration by down-regulating miR-145 and up-regulating SOX9. LncRNA MALAT1 could suppress cell cycle and apoptosis through MALAT1 / miR-145 / SOX9 axis.

High Expression of PhospholipaseD2 Induced by Hypoxia Promotes Proliferation of Colon Cancer Cells through Activating NF- κ Bp65 Signaling Pathway

Hypoxia is a typical feature of colon cancer occurrence and progression. We have reported that high expression and activity of PhospholipaseD2 (PLD2) induced by hypoxia in colon cancer cells. In order to further investigate the role of PLD2 in colon cancer under hypoxic conditions. MTT assay was used to detect the proliferation of human colon cancer cells (SW480 and SW620) under hypoxic conditions by decrease the PLD2 gene expression or inhibit the activity of PLD2. Expression level of p-P65/T-P65 and Cyclin D1 were detected in those cells treated as above through using western blot and RT-PCR analysis. Effect of NF-Bp65 inhibitor (BAY-117082) on the proliferation and expression level of Cyclin D1 and PLD2 of colon cancer cells under hypoxic conditions were further analysised. As a result, decreased the expression of PLD2 or inhibited the activity of PLD2 leaded to the proliferation of hypoxia colon cancer cells reduced, and along with the expression level of p-P65/T-P65 and Cyclin D1 reduced. However, inhibition the expression level of p-P65/T-P65 lead to the proliferation and expression of Cyclin D1 in those hypoxia colon cancer cells also reduced. In vivo growth decreased in response to PLD2 and NF-Bp65 inhibition. Our study indicates that high expression of PLD2 induced by hypoxia promotes the proliferation of colon cancer cells, and it may elevate the expression level of Cyclin D1 through activating NF-Bp65 signaling pathway. Inhibition of the PLD2 expression may provide a new clue for treatment for colon cancer.

A polysaccharide from Lentinus edodes inhibits human colon cancer cell proliferation and suppresses tumor growth in athymic nude mice

The antitumor effect of Lentinan is thought rely on the activation of immune responses; however, little is known about whether Lentinan also directly attacks cancer cells. We therefore investigated the direct antitumor activity of SLNT (a water-extracted polysaccharide from Lentinus edodes) and its probable mechanism. We showed that SLNT significantly inhibited proliferation of HT-29 colon cancer cells and suppressed tumor growth in nude mice. Annxein V-FITC/PI, DAPI, AO/EB and H&E staining assays all showed that SLNT induced cell apoptosis both in vitro and in vivo. SLNT induced apoptosis by activating Caspase-3 via both intrinsic and extrinsic pathways, which presented as the activation of Caspases-9 and -8, upregulation of cytochrome c and the Bax/Bcl-2 ratio, downregulation of NF-κB, and overproduction of ROS and TNF-α in vitro and in vivo. Pretreatment with the caspase-3 inhibitor Ac-DEVD-CHO or antioxidant NAC blocked SLNT-induced apoptosis. These findings suggest that SLNT exerts direct antitumor effects by inducing cell apoptosis via ROS-mediated intrinsic and TNF-α-mediated extrinsic pathways. SLNT may thus represent a useful candidate for colon cancer prevention and treatment.

Upregulated plasmacytoma variant translocation 1 promotes cell proliferation, invasion and metastasis in colorectal cancer

Emerging evidence indicates that the long non-coding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is associated with tumourigenesis in various types of cancer. However, its specific effects on the proliferation, invasion and metastasis of colorectal cancer (CRC) are still poorly understood. The present study aimed to investigate PVT1 expression in CRC and explore its role in CRC pathogenesis. The reverse transcriptase‑quantitative polymerase chain reaction (RT‑qPCR) technique was used to assess PVT1 expression in CRC cell lines. Gene Expression Omnibus (GEO) database analysis and measurement of clinical samples was used to analyse the correlation between PVT1 expression, CRC metastasis and overall survival (OS). In addition, knockdown of PVT1 expression was performed using short interfering RNA (siRNA) and RT‑qPCR, western blotting, CCK‑8 assays, tumour cell clone‑formation and Matrigel invasion assays were used to observe its biological functions in HCT116 cells. The present study demonstrated that the expression of PVT1 in CRC cell lines was higher than that in normal colon mucosal cell lines. Using GEO database analysis and the measurement of clinical samples, it was revealed that CRC patients with high PVT1 expression demonstrated poor OS. Multivariate analysis indicated that high PVT1 expression is an independent risk factor for patients with CRC. In addition, PVT1 knockdown suppressed the proliferation, invasion and metastasis of CRC cells in vitro, which were associated with decreasing vimentin, cyclin D1 and cyclin‑dependent kinase 4 expression and enhanced E‑cadherin expression. The results of the present study suggest that PVT1 may serve a critical role in CRC progression and metastasis and may serve as a potential prognostic biomarker for CRC.

Oncogene and Tumor Suppressor Gene Expression Changes in the Peripheral Blood Leukocytes of Patients with Colorectal Cancer

Aims and background

The mortality of colorectal cancer continues to stagnate despite the development of new therapeutic approaches. Therefore, identifying high-risk population groups could contribute to the prevention of a considerable part of deaths caused by colorectal tumors.

Methods

Fifty patients with colon cancer and 50 patients with other, nonmalignant diseases were selected for the study. Expression of the c-myc, Ha-ras and p53 genes was determined in the peripheral leukocytes of the participants.

Results

Marked elevations of the expression of all three investigated genes were seen in the colon cancer patients when compared to the controls.

Conclusions

Our investigations showed that increases in the expression of c-myc, Ha-ras and p53 genes can be demonstrated in the peripheral leukocytes of colon cancer patients. By applying our method to clinical investigations, individuals with a high risk of having developed colon cancer may be identified and early diagnosis may be established.

TP53 Gene Pro72Arg (rs1042522) Single Nucleotide Polymorphism as Not a Risk Factor for Colorectal Cancer in the Iranian Azari Population

Background:

The p53 protein participates critically in several cellular functions such as cell growth and DNA repair. Polymorphisms in the TP53locus have repeatedly been implicated in the pathogenesis of cancers all over the world. Over 200 single nucleotide polymorphisms (SNPs) have been characterized, but one well-known example at at codon 72, Pro72Arg(rs1042522), has the displayed inconsistent results with regard to cancer risk. Herein, we aimed to evaluate whether Pro72Arg(rs1042522) single nucleotide polymorphism (SNP) in TP53gene might be associated with risk of colorectal cancer in the Iranian Azari population.

Methods:

Blood samples were taken from 100 healthy controls and 100 colorectal cancer patients with Iranian-Azeri ethnicity. Genotyping was performed with Tetra-ARMS PCR.

Results:

The alleles of the TP53gene Pro72ArgSNP did not significantly differ in prevalence between patients and controls (P>0.05). Additionally, genotypes of Pro72ArgSNP were not significantly associated with colorectal cancer risk in the studied population.

Conclusions:

Pro72ArgSNP of TP53gene may not be involved in the disease pathogenesis in Iranian Azari patients with colorectal cancer.

The prognostic significance of protein arginine methyltransferase 6 expression in colon cancer

Protein arginine methylation is involved in cellular differentiation and proliferation. Recently, aberrant expression of protein arginine methyltransferases, which are responsible for the methylation reaction, has been reported in various types of cancer. However, there is no clear evidence regarding the prognostic value of abnormal PRMT6 expression in colorectal cancer or the effect of PRMT6 regulation on CRC cells. We investigated the expression patterns of PRMT6 in patients with stage II and III CRC. We detected nuclear expression of PRMT6 in 23.7% of carcinoma samples by immunohistochemistry. Among the clinicopathological parameters, the ratio of poorly differentiated cancer cells was approximately two-fold higher in patients with PRMT6-positive disease than in those with PRMT6-negative disease (p = 0.002). Patients with PRMT6-positive CRC had a shorter disease-free survival than those with PRMT6-negative CRC in both univariate and multivariate analyses (p = 0.018 and p = 0.035, respectively). siRNA-mediated inhibition of PRMT6 expression in CRC cells induced p21^WAF1/CIP1 overexpression and suppressed cell growth and colony-forming ability. Concomitantly, apoptosis was induced in PRMT6-suppressed CRC cells. These data suggest that PRMT6 can serve as a biomarker for unfavorable prognosis and as a therapeutic target in CRC.

Long non-coding RNA MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in colorectal cancer cells

Our earlier findings indicate that the long non-coding RNA MALAT1 promotes colorectal cancer (CRC) cell proliferation, invasion and metastasis in vitro and in vivo by increasing expression of AKAP-9. In the present study, we investigated the molecular mechanism by which MALAT1 enhances AKAP9 expression in CRC SW480 cells. We found that MALAT1 interacts with both SRPK1 and SRSF1. MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation. Following MALAT1 knockdown, overexpression of SRPK1 was sufficient to restore SRSF1 phosphorylation and AKAP-9 expression to a level that promoted cell proliferation, invasion and migration in vitro. Conversely, SRPK1 knockdown after overexpression of MALAT1 in SW480 cells diminished SRSF1 phosphorylation and AKAP-9 expression and suppressed cell proliferation, invasion and migration in vitro. These findings suggest MALAT1 increases AKAP-9 expression by promoting SRPK1-catalyzed SRSF1 phosphorylation in CRC cells. These results reveal a novel molecular mechanism by which MALAT1 regulates AKAP-9 expression in CRC cells.

SATB2/β-catenin/TCF-LEF pathway induces cellular transformation by generating cancer stem cells in colorectal cancer

Recent studies have demonstrated the involvement of colorectal cancer (CRC) stem cells (CSC) in transformation, cancer progression and metastasis. The main goal of this paper was to examine the molecular mechanisms by which SATB2 induced malignant transformation of colorectal epithelial cells. SATB2 induced malignant transformation and these transformed cells gained the characteristics of CSCs by expressing stem cell markers (CD44, CD133, LGR5 and DCLK1) and transcription factors (c-Myc, Nanog and Sox2). Overexpression of SATB2 in normal colorectal epithelial cells increased cell motility, migration and invasion, which were associated with an increase in N-cadherin and Zeb1, and decrease in E-cadherin expression. SATB2 overexpression also upregulated XIAP and cyclin D1, suggesting its role in cell survival and cell cycle. Furthermore, the expression of SATB2 was positively correlated with β-catenin expression in CRC. In contrary, depletion of SATB2 inhibited cell proliferation, colony formation, cell motility and expression of β-catenin, Snail, Slug, Zeb1 and N-cadherin, and upregulated E-cadherin. Furthermore, SATB2 silencing inhibited the expression of stem cell markers, pluripotency maintaining transcription factors, cell cycle and cell proliferation/survival genes and TCF/LEF targets. Finally, β-catenin/TCF-LEF pathway mediated the biological effects of SATB2 in CSCs. These studies support the role of SATB2/β-catenin/TCF-LEF pathway in transformation and carcinogenesis.

SATB2/β-catenin/TCF-LEF pathway induces cellular transformation by generating cancer stem cells in colorectal cancer

Recent studies have demonstrated the involvement of colorectal cancer (CRC) stem cells (CSC) in transformation, cancer progression and metastasis. The main goal of this paper was to examine the molecular mechanisms by which SATB2 induced malignant transformation of colorectal epithelial cells. SATB2 induced malignant transformation and these transformed cells gained the characteristics of CSCs by expressing stem cell markers (CD44, CD133, LGR5 and DCLK1) and transcription factors (c-Myc, Nanog and Sox2). Overexpression of SATB2 in normal colorectal epithelial cells increased cell motility, migration and invasion, which were associated with an increase in N-cadherin and Zeb1, and decrease in E-cadherin expression. SATB2 overexpression also upregulated XIAP and cyclin D1, suggesting its role in cell survival and cell cycle. Furthermore, the expression of SATB2 was positively correlated with β-catenin expression in CRC. In contrary, depletion of SATB2 inhibited cell proliferation, colony formation, cell motility and expression of β-catenin, Snail, Slug, Zeb1 and N-cadherin, and upregulated E-cadherin. Furthermore, SATB2 silencing inhibited the expression of stem cell markers, pluripotency maintaining transcription factors, cell cycle and cell proliferation/survival genes and TCF/LEF targets. Finally, β-catenin/TCF-LEF pathway mediated the biological effects of SATB2 in CSCs. These studies support the role of SATB2/β-catenin/TCF-LEF pathway in transformation and carcinogenesis.

Casticin induced apoptotic cell death and altered associated gene expression in human colon cancer colo 205 cells

Casticin, a polymethoxyflavone, derived from natural plant Fructus Viticis exhibits biological activities including anti-cancer characteristics. The anti-cancer and alter gene expression of casticin on human colon cancer cells and the underlying mechanisms were investigated. Flow cytometric assay was used to measure viable cell, cell cycle and sub-G1 phase, reactive oxygen species (ROS) and Ca²⁺ productions, level of mitochondria membrane potential (ΔΨ_m ) and caspase activity. Western blotting assay was used to detect expression of protein level associated with cell death. Casticin induced cell morphological changes, decreased cell viability and induced G2/M phase arrest in colo 205 cells. Casticin increased ROS production but decreased the levels of ΔΨ_m , and Ca²⁺ , increased caspase-3, -8, and -9 activities. The cDNA microarray indicated that some of the cell cycle associated genes were down-regulated such as cyclin-dependent kinase inhibitor 1A (CDKN1A) (p21, Cip1) and p21 protein (Cdc42/Rac)-activated kinase 3 (PAK3). TNF receptor-associated protein 1 (TRAP1), CREB1 (cAMP responsive element binding protein 1) and cyclin-dependent kinase inhibitor 1B (CDKN1B) (p27, Kip1) genes were increased but matrix metallopeptidase 2 (MMP-2), toll-like receptor 4 (TLR4), PRKAR2B (protein kinase, cAMP-dependent, regulatory, type II, bet), and CaMK4 (calcium/calmodulin-dependent protein kinase IV) genes were inhibited. Results suggest that casticin induced cell apoptosis via the activation of the caspase- and/or mitochondria-dependent signaling cascade, the accumulation of ROS and altered associated gene expressions in colo 205 human colon cancer cells.

The prognostic value of abnormally expressed lncRNAs in colorectal cancer: A meta-analysis

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent cancer type and the third leading cause of cancer-related deaths worldwide, it is urgently needed to discover a new marker for the progress of CRC. Many long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in CRC, and may be feasible as effective biomarkers and prognostic factors. The aim of this study was to identify the prognostic value of various lncRNAs in CRC.

METHODS

Pubmed, Web of Science, Embase and Cochrane Library were searched for potentially related studies. A total of 34 eligible studies including 30 on overall survival (OS), 7 on disease-free survival (DFS), 1 on relapse-free survival (RFS), 2 on disease-specific survival (DSS) and 29 on clinicopathological features were qualified from the databases.

RESULTS

The results showed that the expression levels of lncRNAs were significantly associated with poor OS (hazard ratio (HR) = 2.08, 95% confidence interval (CI) = 1.68-2.57, P<0.001, I2 = 70%), DFS (HR = 1.79, 95% CI = 1.54-2.08, P<0.001, I2 = 6%) and DSS (HR = 0.11, 95% CI = 0.02-0.54, P = 0.007, I2 = 14%). Subgroup analysis further showed that lncRNA transcription level was significantly associated with tumor differentiation (odds ratio (OR) = 0.51, 95% CI = 0.34-0.77, P = 0.001), lymph node metastasis (OR = 1.63, 95% CI = 1.23-2.17, P = 0.0007), distant metastasis (OR = 2.06, 95% CI = 1.29-3.30, P = 0.002), TNM stage (OR = 0.44, 95% CI = 0.32-0.62, P<0.001), tumor invasion depth (OR = 0.48, 95% CI = 0.39-0.60, P<0.001).

CONCLUSIONS

The meta-analysis demonstrated that abnormal lncRNA transcription level may serve as a promising indicator for prognostic of patients with CRC.

Overexpression of the long non-coding RNA, linc-UBC1, is associated with poor prognosis and facilitates cell proliferation, migration, and invasion in colorectal cancer

Long non-coding RNAs (lncRNAs) serve comprehensive roles in various diseases, including cancer. lncRNA upregulated in bladder cancer 1 (linc-UBC1) is a notable biomarker of prognosis in certain cancer types; however, its involvement in the progression of colorectal cancer (CRC) remains unknown. The present study aimed to investigate the expression of linc-UBC1 in patients with CRC and to investigate its effect on CRC cells. The expression levels of linc-UBC1 were estimated by reverse transcription-quantitative polymerase chain reaction in clinical CRC specimens and matched adjacent non-tumor mucosa from 96 cases of CRC, as well as in a number of CRC cell lines. In addition, the biological roles of linc-UBC1 were examined using a cell counting kit-8 assay, flow cytometry, and migration and invasion assays following the downregulation of linc-UBC1 by small interfering RNA. The results revealed that linc-UBC1 was significantly overexpressed in CRC tissues and the majority of CRC cell lines compared with the matched non-tumor mucosa and normal intestinal epithelial cells. Furthermore, high expression levels of linc-UBC1 were significantly associated with large tumor size, greater tumor depth, lymph node metastasis, and advanced tumor-node-metastasis stages. Patients with abnormal expression of linc-UBC1 had poorer overall survival times according to Kaplan-Meier analyses. Furthermore, multivariate Cox regression analysis indicated that linc-UBC1 was a significant independent prognostic factor. The results also revealed that reducing the expression of linc-UBC1 led to the inhibition of migration, invasion, and proliferation of CRC cells in vitro. Taken together, the results of the present study suggest that overexpression of linc-UBC1 promotes proliferation and metastasis in CRC, and may be considered as a novel diagnostic marker of CRC.

CDK5 functions as a tumor promoter in human colorectal cancer via modulating the ERK5-AP-1 axis

Abnormal expression of cyclin-dependent kinase 5 (CDK5) has been found in several human cancers, whereas the role of CDK5 in the malignant development of colorectal cancer (CRC) has not been well characterized. Here we investigated the role of CDK5 in CRC and found that its expression was much higher in CRC tissues than that in normal tissues with a higher expression level of CDK5 closely correlating to advanced American Joint Committee on Cancer (AJCC) stage, poor differentiation, increased tumor size and poor prognosis of CRC. Biological function experiments showed that CDK5 regulated CRC cell proliferation and metastasis ability. Whole-genome microarray analysis, co-immunoprecipitation, in vitro kinase assay, western blotting, luciferase reporter assays and electrophoretic mobility shift assay (EMSA) showed that CDK5 could directly phosphorylate ERK5 at threonine (Thr) 732 and finally modulate the oncogenic ERK5–AP-1 axis. Further researches showed that CDK5–ERK5–AP-1 axis could promote progression of CRC carcinogenesis and had a significant correlation in human CRC samples. In summary, this study revealed the functional and mechanistic links between CDK5 and the oncogenic ERK5–AP-1 signaling pathway in the pathogenesis of CRC. These findings suggest that CDK5 has an important role in CRC development and may serve as a potential therapeutic target for CRC.

LncRNA DQ786243 contributes to proliferation and metastasis of colorectal cancer both in vitro and in vivo

Accumulating evidence demonstrates that long non-coding RNAs (LncRNAs) play important roles in regulating gene expression and are involved in various cancers, including colorectal cancer (CRC). However, LncRNA profiles in CRC remain largely unknown. The present study aims to find the key LncRNA associated with CRC and to study its biological functions in CRC progression. We focused on LncRNA DQ786243, one of LncRNAs which promoted development of CRC from the Gene Expression Omnibus (GEO) and validated using quantitative real-time PCR among about 20 paired CRC tissues. The effects of LncRNA DQ786243 were assessed by silencing the LncRNA in vitro and in vivo Results showed that the expression level LncRNA DQ786243 was significantly higher in CRC tissues and cell lines. We also found LncRNA DQ786243 knockdown by RNA interference with siRNA significantly arrested the cell cycle in the G2/M-phase, promoted apoptosis and weaken the abilities of cell proliferation and invasion in vitro Further investigation into the mechanisms responsible for the growth inhibitory effects by DQ786243 silencing revealed that its knockdown resulted in the induction of cell cycle arrest and apoptosis through certain cell cycle-related and apoptosis-related proteins. Finally, xenograft experiments confirmed that the growth of xenograft tumours formed by CRC cells was suppressed after silencing LncRNA DQ786243 expression. In conclusion, the present study suggests that LncRNA DQ786243 is an oncogene that promotes tumour progression and leads us to propose that LncRNAs may serve as key regulatory hubs in CRC progression.

Promoter hypermethylation and downregulation of the FAS gene may be involved in colorectal carcinogenesis

Aberrant DNA methylation has been investigated in carcinogenesis and as biomarker for the early detection of colorectal cancer (CRC). The present study aimed to define the methylation status in the regulatory elements of two proapoptotic genes, Fas cell surface death receptor (FAS) and BCL2-associated X protein (BAX). DNA methylation analysis was performed in tumor and adjacent normal tissue using HpaII/MspI restriction digestion and methylation-specific polymerase chain reaction (PCR). The results observed downregulation of the FAS and BAX genes in the CRC tissues compared with the adjacent normal samples. Furthermore, demethylation using 5-aza-2'-deoxycytidine treatment followed by reverse-transcription quantitative PCR were performed on the HT-29 cell line to measure BAX and FAS mRNA expression following demethylation. The 5-aza-2'-deoxycytidine treatment resulted in significant FAS gene upregulation in the HT-29 cell line, but no significant difference in BAX expression. Furthermore, analysis of CpG islands in the FAS gene promoter revealed that the FAS promoter was significantly hypermethylated in 53.3% of tumor tissues compared with adjacent normal samples. Taken together, the results indicate that decreased expression of the FAS gene due to hypermethylation of its promoter may lead to apoptotic resistance, and acts as an important step during colorectal carcinogenesis.

FOXP3 and CEACAM6 expression and T cell infiltration in the occurrence and development of colon cancer

The transcription factor forkhead box P3 (FOXP3) is involved in immune cell regulation, and carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is an adhesion molecule of the immunoglobulin superfamily. These two genes are associated with cancer progression. In the current study, colon tissue specimens from 78 cases of colon cancer (including 40 of stage I-II and 38 of stage III-IV), 30 cases of colonic adenoma and 12 healthy controls were collected from the First Affiliated Hospital of Soochow University between January 2010 and December 2011. The expression of cluster of differentiation (CD) 3, CD4, CD8, CD45RO, CEACAM6 and FOXP3 in colon tissues was examined by immunohistochemical analysis. In addition, a reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay, based on SYBR Green I, was used to detect CD3, CD4, CD8, CD45RO, CEACAM6 and FOXP3 mRNA levels in the paraffin block specimens. CD3⁺, CD8⁺ and CD45RO⁺ T cell infiltrations in colonic adenoma were significantly higher than in normal colonic mucosa (P<0.001, P=0.001 and P<0.001, respectively). However, CD3⁺, CD8⁺ and CD45RO⁺ lymphocytes in stage III-IV colon cancer tissues were lower than in normal control tissues (P=0.015, P=0.002 and P=0.041, respectively); consistently, CD3⁺, CD4⁺, CD8⁺ and CD45RO⁺ lymphocytes in stage III-IV tissues were even more markedly lower compared with adenoma (P=0.001, P<0.001, P<0.001 and P<0.001, respectively). Similarly, CD3⁺, CD8⁺ and CD45RO⁺ T cell infiltration was lower in stage I-II cancer tissues compared with adenoma (P=0.001, P<0.001 and P<0.001). CD3⁺, CD4⁺, CD8⁺ and CD45RO⁺ T cell infiltrations were also significantly higher in stage I-II compared with stage III-IV cancer tissues (P<0.001, P=0.045, P<0.001 and P<0.001, respectively). CEACAM6 was found to gradually increase from normal colon tissue to adenoma and cancer tissue. FOXP3 was expressed more highly in stage I-II compared with normal tissues (P=0.014), and was even higher in stage III-IV (P<0.001). These results were verified using RT-qPCR, which yielded almost identical results. In summary, the current study demonstrates that FOXP3, CEACAM6 and T cell infiltration are significantly associated with the occurrence and progression of colon cancer, and that immune reactions vary between different stages of colon cancer development.

AKAP-9 promotes colorectal cancer development by regulating Cdc42 interacting protein 4

Our previous studies have shown that PRKA kinase anchor protein 9 (AKAP-9) is involved in colorectal cancer (CRC) cell proliferation and migration in vitro. However, whether or not AKAP-9 is important for CRC development or metastasis in vivo remains unknown. In the present study, we found that AKAP-9 expression was significantly higher in human colorectal cancer tissues than the paired normal tissues. In fact, AKAP-9 level correlated with the CRC infiltrating depth and metastasis. Moreover, the higher AKAP-9 expression was associated with the lower survival rate in patients. In cultured CRC cells, knockdown of AKAP-9 inhibited cell proliferation, invasion, and migration. AKAP-9 deficiency also attenuated CRC tumor growth and metastasis in vivo. Mechanistically, AKAP-9 interacted with cdc42 interacting protein 4 (CIP4) and regulated its expression. CIP4 levels were interrelated to the AKAP-9 level in CRC cells. Functionally, AKAP-9 was essential for TGF-β1-induced epithelial-mesenchymal transition of CRC cells, and CIP4 played a critical role in mediating the function of AKAP-9. Importantly, CIP4 expression was significantly up-regulated in human CRC tissues. Taken together, our results demonstrated that AKAP-9 facilitates CRC development and metastasis via regulating CIP4-mediated epithelial-mesenchymal transition of CRC cells.

Association between indel polymorphism in the promoter region of lncRNA GAS5 and the risk of hepatocellular carcinoma

The growth arrest special 5 (GAS5) is known to be involved in various cancers. However, its expression regulation remains unclear. Polymorphisms in the promoter region of GAS5 may affect its expression and be associated with cancer susceptibility. In this research, we first evaluated the association of a 5-base pair indel polymorphism (rs145204276) in the promoter region of GAS5 with hepatocelluar carcinoma (HCC) susceptibility in Chinese populations. Logistic regression analysis showed that the deletion allele of rs145204276 significantly increased the risk of HCC in two independent case control sets (1034 HCC and 1054 controls). Further genotype-phenotype association analysis revealed that the deletion allele was markedly correlated with higher expression of GAS5 in HCC tissues. The luciferase activity analysis in an in vitro reporter gene system suggested that the deletion allele improved an increased expression of GAS5 in three hepatoma cell lines. Intriguingly, overexpression of GAS5 displayed an anti-apoptosis effect in HCC cell lines, GAS5 knockdown could partially revert this anti-apoptosis effect, suggesting that GAS5 may act as a proto-oncogene in HCC, in contrast with its inhibitory role in other cancers. Further pyrosequencing revealed that the genotypes of rs145204276 were associated with methylation status of GAS5 promoter region. Taken together, our findings provided evidence that rs145204276 may contribute to hepatocarcinogenesis by affecting methylation status of the GAS5 promoter and subsequently its transcriptional activity thus serving as a potential therapy target for HCC.

Enterobacter Strains Might Promote Colon Cancer

Many studies have been performed to determine the interaction between bacterial species and cancer. However, there has been no attempts to demonstrate a possible relationship between Enterobacter spp. and colon cancer so far. Therefore, in the present study, it is aimed to investigate the effects of Enterobacter strains on colon cancer. Bacterial proteins were isolated from 11 Enterobacter spp., one Morganella morganii, and one Escherichia coli strains, and applied onto NCM460 (Incell) and CRL1790 (ATCC) cell lines. Cell viability and proliferation were determined in MTS assay. Flow Cytometry was used to detect CD24 level and apoptosis. Real-Time PCR studies were performed to determine NFKB and Bcl2 expression. Graphpad Software was used for statistical analysis. The results showed that proteins, isolated from the Enterobacter spp., have significantly increased cell viability and proliferation, while decreasing the apoptosis of the cell lines tested. The data in the present study indicated that Enterobacter strains might promote colon cancer. Moreover, Enterobacter spp. could be a clinically important factor for colon cancer initiation and progression. Studies can be extended on animal models in order to develop new strategies for treatment.

p,p′-Dichlorodiphenyltrichloroethane inhibits the apoptosis of colorectal adenocarcinoma DLD1 cells through PI3K/AKT and Hedgehog/Gli1 signaling pathways

p,p′-Dichlorodiphenyltrichloroethane is able to inhibit the apoptosis of human colorectal adenocarcinoma cells, which may be an important mechanism to contribute to colorectal cancer development.

Long noncoding RNA GAS5 affects cell proliferation and predicts a poor prognosis in patients with colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Recent studies have shown that lncRNAs play important roles in carcinogenesis. The aim of this study was to explore the role of lncRNA GAS5 in CRC. Real-time PCR was performed to investigate the expression of GAS5 in tumor tissues and corresponding non-tumor colorectal tissues from 66 patients with CRC. The lower expression of GAS5 was significantly correlated with large tumor size, low histological grade and advanced TNM stage. Multivariate analyses revealed that GAS5 expression served as an independent predictor for overall survival (P = 0.034). Further experiments revealed that overexpressed GAS5 significantly repressed the proliferation both in vitro and in vivo. In conclusion, our results suggest that GAS5, as a growth regulator, may serve as a candidate prognostic biomarker in human colorectal cancer.

Cell specific apoptosis by RLX is mediated by NFκB in human colon carcinoma HCT-116 cells

Background

Resistance to chemotherapy represents a major obstacle in correcting colorectal carcinomas (CRC). Inspite of recent advances in the treatment of metastatic disease, the prognosis of the patients remains poor. RLX, a vasicinone analogue has been reported to possess potent bronchodilator, anti-asthmatic and anti-inflammatory properties. However, its anti-cancer activity is unknown.

Results

Here, we report for the first time that RLX has anti-cancer property against panel of human cancer cell lines and most potent activity was found against HCT-116 cells with IC₅₀ value of 12 μM and have further investigated the involvement of NFκB and caspase-3 in RLX action in CRC apoptosis. Following RLX and BEZ-235 treatment in HCT-116, we observed significant down-regulation of NFκB (1 to 0.1 fold) and up-regulation of caspase-3 (1 to 2 fold) protein expressions. Additionally, morphological studies revealed membrane blebbing, cell shrinkage, chromatin condensation and finally apoptosis in HCT-116 cells.

Conclusions

Overall, these findings indicate that RLX is a potent small molecule which triggers apoptosis, and promising potential candidate to be a chemotherapeutic agent.

FOXC2 promotes colorectal cancer proliferation through inhibition of FOXO3a and activation of MAPK and AKT signaling pathways

Abnormal expression of FOXC2 has been found in several human cancers. However, the role of FOXC2 in the progression of colorectal cancer (CRC) has not been well characterized. In analysis of 206 CRC specimens, we revealed that both high expression and nuclear localization of FOXC2 were correlated to aggressive characteristics and poor survival of patients with CRC. FOXC2 promoted cell proliferation through activation of MAPK and AKT pathways, subsequently down-regulating p27, up-regulating cyclin D1 and p-FOXO3a. Furthermore, FOXC2 nuclear localization was required for its promotion of cell proliferation. These findings suggest that FOXC2 plays an essential role in CRC progression and may serve as a valuable clinical prognostic marker of this disease.

The role of insulin-like growth factor 1 and its receptor in the formation and development of colorectal carcinoma

OBJECTIVE

To investigate the role of insulin-like growth factor (IGF)-1 and its receptor (IGF1R) in the formation and development of colorectal carcinoma.

METHODS

Colorectal tissue and matching serum samples were collected from patients with adenomatous polyps or carcinoma and healthy control subjects. IGF1R mRNA levels were determined via quantitative real-time reverse transcription-polymerase chain reaction. Serum IGF1 was quantified using enzyme-linked immunosorbent assay.

RESULTS

Serum IGF1 concentrations and mucosal IGF1R mRNA levels were significantly higher in patients with adenomatous polyps (n = 24) or carcinoma (n = 13) compared with healthy control subjects (n = 13). There was a significant positive correlation between serum IGF1 and mucosal IGF1R mRNA in patients with adenomatous polyps.

CONCLUSIONS

High circulating IGF1 concentrations and mucosal IGF1R expression may play important roles in both the formation and development of colorectal carcinoma. IGF1 and its receptor may be activated before carcinogenesis, and may promote the growth and malignant transformation of adenomatous polyps. IGF1 and IGF1R may be useful biomarkers for evaluating the stage and risk of carcinogenesis.

Mechanisms of the anti-proliferative and anti-inflammatory effects of the herbal fixed combination STW 5 (Iberogast®) on colon adenocarcinoma (HT29) cells in vitro

INTRODUCTION

Several conventional pharmaceuticals like non-steroidal anti-inflammatory drugs (NSAIDS) or selective cyclooxygenase-2 (COX-2) inhibitors have been demonstrated to exert anti-proliferative effects and to induce apoptosis in a variety of cell lines, e.g. colon, stomach, or prostate cancer cells. STW 5 (Iberogast(®)), a combination of nine plant extracts, is widely used in the treatment of gastrointestinal disorders, including functional dyspepsia and irritable bowel syndrome for which the involvement of an inflammatory etiology is discussed. To investigate the possible anti-proliferative effects, STW 5 and its components have been tested by using the colon-carcinoma cell line HT-29. The analyses have been performed in comparison to acetylsalicylic acid (ASA) and diclofenac (Diclo), which are well-known to reduce colon carcinoma risk.

RESULTS

STW 5 showed significant anti-proliferative and pro-apoptotic effects on HT-29 cancer cells, similar to NSAIDs under test. However, using the LDH assay, STW 5 revealed significantly lower cytotoxicity than Diclo at same concentrations. In contrast to NSAIDs, STW 5 induced COX-1/COX-2, caspase-3 and Bax mRNA expressions in HT-29 and blocked LPS mediated translocation of the NF-κB p65 from the cytoplasm into the nucleus in PMA-differentiated THP-1 macrophages. These effects might be relevant, e.g. for prevention of undesirable side effects like gastric erosions.

CONCLUSION

Our data suggest that the pro-apoptotic effect of STW 5 on HT-29 cells is involving multiple targets and is possibly due to an activation of the caspase cascade via mitochondrial destabilization. Active concentrations of STW 5 are, in relation to therapeutic doses, comparable to those of ASA and Diclo, suggesting a similar favorable effect on colon carcinoma risk.

Graphite Web: Web tool for gene set analysis exploiting pathway topology

Graphite web is a novel web tool for pathway analyses and network visualization for gene expression data of both microarray and RNA-seq experiments. Several pathway analyses have been proposed either in the univariate or in the global and multivariate context to tackle the complexity and the interpretation of expression results. These methods can be further divided into ‘topological’ and ‘non-topological’ methods according to their ability to gain power from pathway topology. Biological pathways are, in fact, not only gene lists but can be represented through a network where genes and connections are, respectively, nodes and edges. To this day, the most used approaches are non-topological and univariate although they miss the relationship among genes. On the contrary, topological and multivariate approaches are more powerful, but difficult to be used by researchers without bioinformatic skills. Here we present Graphite web, the first public web server for pathway analysis on gene expression data that combines topological and multivariate pathway analyses with an efficient system of interactive network visualizations for easy results interpretation. Specifically, Graphite web implements five different gene set analyses on three model organisms and two pathway databases. Graphite Web is freely available at http://graphiteweb.bio.unipd.it/.

Meta-analysis: selective serotonin reuptake inhibitors and colon cancer

OBJECTIVE

To perform meta-analyses using observational studies to assess the association between the use of selective serotonin reuptake inhibitors (SSRIs) and the risk of colorectal cancer.

METHODS

A systematic search of relevant studies published through February 2012 was carried out using the Medline (PubMed), Embase, and Cochrane Library databases. We reviewed the observational studies that were associated with our subject and carried out a meta-analysis.

RESULTS

Out of 324 screened articles, six observational studies were included in the final analyses. According to this meta-analysis, the use of SSRIs was not associated with an increased risk of colorectal cancer in pooled analyses (adjusted odds ratio 0.89, 95% confidence interval 0.79-1.01). This finding was consistently observed in subgroup analyses of study area, location of colorectal cancer, duration of SSRI use, study quality, adjustment for NSAID use, and the prevalence of overweight.

CONCLUSION

Our research shows that the use of SSRIs does not increase the risk of colorectal cancer. Further studies are needed to confirm the association between SSRIs and colorectal cancer.

An intermittent approach for cancer chemoprevention

Cancer chemoprevention approaches generally use long-term, continuous treatment, which can produce major preventive effects but which can also have unexpected serious adverse events. This raises the question of whether intermittent dosing schedules might reduce toxicity while retaining benefit, a concept that we call short-term intermittent therapy to eliminate premalignancy (SITEP). Recent preclinical studies support a novel SITEP approach whereby short-term, intermittent therapy eliminates premalignant cells via apoptosis that is induced by synthetic lethal interactions. Synthetic lethality allows personalized, selective elimination of premalignant clones without harming normal cells. This Opinion article provides a detailed discussion of the principle, method and future development of the SITEP approach.