Molecular pathogenesis of colorectal cancer: implications for molecular diagnosis

The Impact of Palliative Care on Mitigating Pain and Its Associated Effects in Determining Quality of Life among Colon Cancer Outpatients

Pain continues to be a significant problem for cancer patients, and the impact of a population-based strategy on their experiences is not completely understood. Our study aimed to determine the impact of palliative care on mitigating pain and its associated effects in determining the quality of life (QoL) among colon cancer outpatients. Six collection databases were used to perform a structured systematic review of the available literature, considering all papers published between the year 2000 and February 2023. PRISMA guidelines were adopted in our study, and a total of 9792 papers were evaluated. However, only 126 articles met the inclusion criteria. A precise diagnosis of disruptive colorectal cancer (CRC) pain disorders among patients under palliative care is necessary to mitigate it and its associated effects, enhance health, promote life expectancy, increase therapeutic responsiveness, and decrease comorbidity complications. Physical activities, the use of validated pain assessment tools, remote outpatient education and monitoring, chemotherapeutic pain reduction strategies, music and massage therapies, and bridging social isolation gaps are essential in enhancing QoL. We recommend and place a strong emphasis on the adoption of online training/or coaching programs and the integration of formal and informal palliative care systems for maximum QoL benefits among CRC outpatients.

Modulatory Properties of Aloe secundiflora's Methanolic Extracts on Targeted Genes in Colorectal Cancer Management

Colon tumors have a very complicated and poorly understood pathogenesis. Plant-based organic compounds might provide a novel source for cancer treatment with a sufficient novel mode of action. The objective of this study was to analyze and evaluate the efficacy of Aloe secundiflora's (AS) methanolic extracts on the expression of CASPS9, 5-LOX, Bcl2, Bcl-xL, and COX-2 in colorectal cancer (CRC) management. Caco-2 cell lines were used in the experimental study. In the serial exhaustive extraction (SEE) method, methanol was utilized as the extraction solvent. Upon treatment of CASPS9 with the methanolic extracts, the expression of the genes was progressively upregulated, thus, dose-dependently increasing the rate of apoptosis. On the other hand, the expressions of 5-LOX, Bcl2, and Bcl-xL were variably downregulated in a dose-dependent manner. This is a unique novel study that evaluated the effects of AS methanolic extracts in vitro on CRC cell lines using different dosage concentrations. We, therefore, recommend the utilization of AS and the application of methanol as the extraction solvent of choice for maximum modulatory benefits in CRC management. In addition, we suggest research on the specific metabolites in AS involved in the modulatory pathways that suppress the development of CRC and potential metastases.

Regulatory activities of Warbugia ugandensis ethanolic extracts on colorectal cancer-specific genome expression dose-dependently

The evaluation of natural biomass sources is a promising strategy in accelerating the development of novel anti-cancer medications. Our study aimed to evaluate the activity of W. ugandensis ethanolic roots and stems extracts on the expression of five targeted genes (COX-2, CASPS-9, Bcl-xL, Bcl2 and 5-LOX) in colorectal cancer (CRC) cell lines (Caco-2). Plant extracts were obtained using serial exhaustive extraction and dissolved in Dimethyl sulfoxide appropriately for bioassay. Caco-2 cell lines were passaged, treated with plant extracts at varying concentrations and their RNA's isolated for evaluation. Our unique study reports on W. ugandensis as efficient natural inhibitors of CRC growth, by directly linking its phytoconstituents to; downregulation of COX-2, 5-LOX, Bcl-xL, Bcl2 and upregulation of CASPS9 genes dose-dependently. We present W. ugandensis ethanolic roots and stems extracts as promising natural inhibitors for CRC carcinogenesis and recommend in vivo and subsequent clinical trials, with substantial clinical effects postulated. We further suggest studies on identification and characterization of the specific metabolites in W. ugandensis involved in the modulatory mechanisms, resulting to inhibition of CRC growth and possible metastases.

The Effect of Silencing the Genes Responsible for the Level of Sphingosine-1-phosphate on the Apoptosis of Colon Cancer Cells

Sphingosine-1-phosphate (S1P) and ceramides (Cer) are engaged in key events of signal transduction, but their involvement in the pathogenesis of colorectal cancer is not conclusive. The aim of our study was to investigate how the modulation of sphingolipid metabolism through the silencing of the genes involved in the formation (SPHK1) and degradation (SGPL1) of sphingosine-1-phosphate would affect the sphingolipid profile and apoptosis of HCT-116 human colorectal cancer cells. Silencing of SPHK1 expression decreased S1P content in HCT-116 cells, which was accompanied by an elevation in sphingosine, C18:0-Cer, and C18:1-Cer, increase in the expression and activation of Caspase-3 and -9, and augmentation of apoptosis. Interestingly, silencing of SGLP1 expression increased cellular content of both the S1P and Cer (C16:0-; C18:0-; C18:1-; C20:0-; and C22:0-Cer), yet inhibited activation of Caspase-3 and upregulated protein expression of Cathepsin-D. The above findings suggest that modulation of the S1P level and S1P/Cer ratio regulates both cellular apoptosis and CRC metastasis through Cathepsin-D modulation. The cellular ratio of S1P/Cer seems to be a crucial component of the above mechanism.

Are chemical compounds in medical mushrooms potent against colorectal cancer carcinogenesis and antimicrobial growth?

After cardiovascular diseases, cancer is the second main cause of death globally. Mushrooms have been demonstrated to contain amalgamation with properties capable of inhibiting carcinogenesis and microbial growth, principally secondary metabolites such as quinolones, steroids, terpenes, anthraquinones, and benzoic acid derivatives among others. This study aimed to substantiate their potency concerning colon cancer carcinogenesis and antimicrobial growth. A systematic search of important literature was performed considering all the articles published until April 2022. Screening was performed by searching the BMC Springer, Elsevier, Embase, Web of Science, Ovid, and MEDLINE databases. In addition, Google Scholar was used to supplement information. Titles and abstracts that matched the established criteria were selected for full-text article scrutiny and subsequently used in the updated present review. Bioactive compounds present in medicinal mushrooms such as ascorbic acid, organic acids, flavonoids, polysaccharides, glycosides, phenols, linoleic acid, grifolin, and tocopherols among other compounds play a key role in suppressing the proliferation of cancerous cells and selectively act as antibacterial and antifungal agents. These metabolites actively scavenge oxygen free radicals, hydroxyl radicals, and nitrite radicals that would otherwise increase the risks of the growth and development of cancerous cells. Mushrooms' bioactive compounds and metabolites actively inhibit nuclear factor-kappa activation, protein kinase B processes, and ultimately the expression of Cyclooxygenases 2 in cancerous cells. Medicinal mushrooms should be considered as alternative natural chemo-preventive agents in the global fight against colon cancer and the evolution of drug-resistant pathogenic microorganisms, as they exhibit robust potency. They have not been reported to exhibit adverse harmful effects compared to synthetic chemotherapies, yet they have been reported to demonstrate significant beneficial effects.

Interactive Relationships between Intestinal Flora and Bile Acids

The digestive tract is replete with complex and diverse microbial communities that are important for the regulation of multiple pathophysiological processes in humans and animals, particularly those involved in the maintenance of intestinal homeostasis, immunity, inflammation, and tumorigenesis. The diversity of bile acids is a result of the joint efforts of host and intestinal microflora. There is a bidirectional relationship between the microbial community of the intestinal tract and bile acids in that, while the microbial flora tightly modulates the metabolism and synthesis of bile acids, the bile acid pool and composition affect the diversity and the homeostasis of the intestinal flora. Homeostatic imbalances of bile acid and intestinal flora systems may lead to the development of a variety of diseases, such as inflammatory bowel disease (IBD), colorectal cancer (CRC), hepatocellular carcinoma (HCC), type 2 diabetes (T2DM), and polycystic ovary syndrome (PCOS). The interactions between bile acids and intestinal flora may be (in)directly involved in the pathogenesis of these diseases.

Medicinal plants with anti-colorectal cancer bioactive compounds: Potential game-changers in colorectal cancer management

Development and identification of molecular compounds capable of killing or inhibiting transformed cells promoting carcinogenesis without inducing toxic effects to the normal cells are of utmost significance. A systematic review was conducted in screening for important literature was extensively performed by searching the Web of Science, Ovid, BMC Springer, Elsevier, Embase, and MEDLINE databases for optimum selectivity. Google Scholar was also used to supplement information. Pharmacotherapeutic biomolecules active against colon cancer carcinogenesis in Musa acuminata and Musa balbisiana (bananas), Punica granatum L (pomegranate), Glycine max (Soybean), Brassica oleracea L var. italica Plenck (Broccoli), and Hibiscus rosa-sinesis and Hibiscus sabdariffa (hibiscus) were evaluated. Signaling pathways like phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase (MAPK), protein kinase B (AKT), and nuclear factor-kappa B (NFκB) correlate the mediation of COX-2 expression. Increased levels of COX-2 are correlated with the occurrence and progression of colon cancer. Natural antioxidants in herbal plants including polyphenols and carotenoids inhibit the oxidation of lipids, proteins, and nucleic acids and thereby preventing the initiation of oxidizing chain reactions. These bioactive compounds should be considered an important dietary supplement.

Discovery of Synergistic Drug Combinations for Colorectal Cancer Driven by Tumor Barcode Derived from Metabolomics “Big Data”

The accumulation of cancer metabolomics data in the past decade provides exceptional opportunities for deeper investigations into cancer metabolism. However, integrating a large amount of heterogeneous metabolomics data to draw a full picture of the metabolic reprogramming and to discover oncometabolites of certain cancers remains challenging. In this study, a tumor barcode constructed based upon existing metabolomics “big data” using the Bayesian vote-counting method is proposed to identify oncometabolites in colorectal cancer (CRC). Specifically, a panel of oncometabolites of CRC was generated from 39 clinical studies with 3202 blood samples (1332 CRC vs. 1870 controls) and 990 tissue samples (495 CRC vs. 495 controls). Next, an oncometabolite-protein network was constructed by combining the tumor barcode and its involved proteins/enzymes. The effect of anti-cancer drugs or drug combinations was then mapped into this network by the random walk with restart process. Utilizing this network, potential Irinotecan (CPT-11)-sensitizing agents for CRC treatment were discovered by random forest and Xgboost. Finally, a compound named MK-2206 was highlighted and its synergy with CPT-11 was validated on two CRC cell lines. To summarize, we demonstrate in the present study that the metabolomics “big data”-based tumor barcodes and the subsequent network analyses are potentially useful for drug combination discovery or drug repositioning.

Linking insulin like growth factor-1 (IGF-1) rs6214 gene polymorphism and its serum level with risk of colorectal cancer

Background

Colorectal Cancer is found one of the most profound type of cancer around globe, affecting men and women with different ethnic and racial groups. Insulin-like growth factor 1 is known as peptide growth factor found to increase the proliferation of cell and prevent apoptosis. Insulin pathway might have linked with progression of colorectal cancer.

Methods

This study conducted on total 160 subjects, including 80 patients with colorectal cancer with 80 age and gender match controls. Clinical parameters were compared between the control group and Colorectal cancer group. Blood serum IGF-1 was quantified by using ELISA and IGF-1 rs6214(C/T) variations were investigated using TaqMan allelic discrimination assay.

Results

Blood serum level of Insulin growth factor-I (ng/ml) showed substantial association concerning groups while IGF-1 rs6214(C/T) genotype distribution observed increased in colorectal cancer patients as compared to controls with significant association. The variant TT and CT genotype frequency observed more common in cases as compared to control. However, the wild type CC genotype were common in cases used to compared with controls. The Odds Ratio reveal the risk of variant IGF-1 rs6214 T allele to increase 3 times compared to wild type allele.

Conclusion

The homozygous TT genotypes and T variant allele of IGF-1 rs6214(C/T) showed association with high serum Insulin growth factor level 1, may increase susceptibility to the colorectal cancer. This work will use to investigate the associations between Insulin-like growth factor 1 and rs6214(C/T) gene variant and blood serum level with the vulnerability to treat Colorectal. In summary, we have investigated the relationship between Insulin growth factor level hormone and colorectal cancer. Further studies are required to understand the association between colorectal cancer and polymorphism. However, this study can be serve as an informative study to uncover mechanisms behind main cause of colon cancer. Therefore, the genomic profiling of Insulin-like growth factor-1 can be helpful to treat colorectal cancer patients.

Cryptosporidium and colorectal cancer: a review of epidemiology and possible association

Cryptosporidiosis is an important protozoan disease with serious public health implications. The contribution of Cryptosporidium to colorectal cancer is still vaguely studied, but little evidence from experimental and epidemiological studies has suggested a possible association. This review discusses the epidemiology of cryptosporidiosis and colorectal cancer and attempts to unravel the possible link between the two diseases using epidemiological, pathological, molecular, and immunological evidence. The review stressed the need to undertake more studies in this relatively neglected field.

CTHRC1 is a prognosis-related biomarker correlated with immune infiltrates in colon adenocarcinoma

Background

Colon adenocarcinoma (COAD) is one of the common cancers worldwide. Collagen triple helix repeat containing 1 (CTHRC1) has been reported to be involved in cell invasion, angiogenesis, and the promotion of epithelial-mesenchymal transformation by mediating multiple signaling pathways. However, the role of CTHRC1 in COAD has not yet been determined.

Methods

Differentially expressed genes were evaluated using gene expression data from the Oncomine and TIMER databases. Correlations between CTHRC1 gene expression and clinicopathological factors were analyzed using gene expression data from UALCAN databases. Then, we searched the GEPIA database to evaluate the association of CTHRC1 gene expression with clinical outcomes. The cBioPortal database was used to analyze CTHRC1 genetic alterations. Subsequently, the TIMER website was chosen to assess the correlation of CTHRC1 with the tumor immune cell infiltration level. The TCGA dataset was used for a gene set enrichment analysis (GSEA).

Result

CTHRC1 was highly expressed in COAD patients, and significantly related to poor prognosis. In addition, elevated expression of CTHRC1 was related to the clinical stage and pathological type of COAD. The GSEA analysis showed that CTHRC1 was enriched in Gα signaling, GCPR ligand binding, neutrophil degranulation, interleukin signaling, and tumor-associated pathways. In addition, CTHRC1 was significantly associated with the expression of multiple immune markers related to specific immune cells.

Conclusion

This study suggest that CTHRC1 expression is related to the prognosis and immune infiltration of COAD patients. Therefore, CTHRC1 may be a new candidate prognostic biomarker for determining immune infiltration levels and providing COAD prognoses.

The implication of BRAF mutation in advanced colorectal cancer

BACKGROUND

Advanced colorectal cancer (CRC) is frequently a lethal disease. Mutations in the BRAF gene is a key driver in CRC pathogenesis and confers a poor prognosis. To date, Irish data on this molecular subtype of CRC is lacking.

AIMS

Our aim was to compare the natural history of Irish patients with BRAF (BRAF^MUT) metastatic CRC with a control group of metastatic CRC patients without BRAF mutation (BRAF^WT wild- type).

METHOD

A retrospective observational analysis of advanced CRC patients with known BRAF^MUT was conducted by chart review. BRAF^MUT patients were identified from the Cork University Hospital (CUH) histopathology database. Controls with known BRAF^WT were randomly selected from the database. Demographic characteristics and clinicopathological data were recorded. Survival was assessed with Kaplan-Meier curve/Cox proportional hazard models.

RESULTS

Twenty patients with BRAF^MUT and 36 with BRAF^WT were studied. BRAF^MUT were more likely female (75% vs 33%, p = 0.007) and right-sided (65% vs 31.4%, p = 0.033). Median overall survival was lower in BRAF^MUT group (17.3 months (95% CI 0-40.8)) compared to patients with BRAF^WT (median survival not reached, log rank p = 0.001). On multivariate analysis, BRAF^MUT was independently associated with an increased risk of mortality (HR 12.76 (95% CI 3.15-51.7), p < 0.001).

CONCLUSION

BRAF^MUT advanced colorectal cancer was associated with significantly reduced overall survival in this Irish CRC population. Knowledge of mutation status should now be considered standard of care and should dictate management. Surgeons should be aware of this genetic signature as the natural history of the disease may mitigate against an aggressive surgical strategy. A prospective study should be conducted to further corroborate these findings.

A new method for investigating microbiota-produced small molecules in adenomatous polyps

The intestinal microbiota is composed of a large number of different bacteria that produce a variety of metabolites. Colorectal cancer, which typically develops from adenomatous polyps, is highly influenced by microbiota. Since a variety of molecular changes may occur as these polyps transform from benign tumor to malignant carcinoma, the ability to study the microbiota-produced metabolites can lead to new discoveries about the development and progression of this cancer. However, to address the complexity of the microbiota-produced molecules, novel methods are needed. To this aim, in the present work, we developed a high-throughput metabolomics method to capture the metabolic complexity of the microbiota metabolome adherent to adenomatous polyps and adenocarcinoma. For the first time, the method enables the simultaneous quantification of almost 300 metabolites, while preserving the integrity of the original sample. The metabolomics approach was analytically validated and had excellent performances in terms of recovery, linearity, specificity, intra- and inter-day precision, limits of detection, and quantification. Furthermore, the clinical potential of the method was demonstrated in adenoma collected for a colorectal adenoma study.

Is the nuclear factor kappa-b (NF-κB) pathway and inflammatory status associated with colorectal cancer?

BACKGROUND

Although genetic predisposition has a role in the etiology of colorectal cancer, there are many other factors that affect its development. In this study, it was aimed to evaluate the NF-κB pathway, inflammatory status and dietary antioxidant capacity in individuals with colorectal cancer.

METHODS

The study was carried out with 40 male subjects diagnosed with colorectal cancer aged between 39-65, years and a control group of the same number of healthy men. Subjects in the case and control groups were subdivided according to body mass index (BMI), as normal (BMI 20-24.9 kg/m²) or overweight/obese (BMI ≥25 kg/m²).

RESULTS

At the end of the study, NF-κB and interleukin-22 levels were higher in the case group, but no significant difference was found between the groups. Interleukin-23 and 8-Hydroxy-2-deoxyguanosine levels in the case group classified as overweight/obese according to BMI were significantly higher than in the control group (P = 0.001 and P < 0.001, respectively). Considering diet antioxidant capacity, it was higher in individuals in the control group than in the case group. However, there was no significant difference between the groups.

CONCLUSION

Inflammatory status and reduced dietary antioxidant capacity are risk factors in the development of colorectal cancer.

High expression of CD133 - stem cell marker for prediction of clinically agressive type of colorectal cancer

&lt;b&gt; Background:&lt;/b&gt; Colorectal cancer (CRC) is one of the most common malignancies in the world. The cancer stem cell (CSC) markers are associated with aggressive cancer types and poor prognosis. The objective of the study was to evaluate the CD133 expression and to correlate it with clinicopathological features in patients with CRC. &lt;br&gt;&lt;b&gt;Material and Methods:&lt;/b&gt; Our study included ninety patients with CRC who underwent curative surgical resection from 2012 to 2017 at the University Clinic for Digestive Surgery, Skopje, North Macedonia. Tumor samples were first analyzed with standard histopathological methods and then the CD133 expression was investigated immunohistochemically. The level of expression of CD133 was classified semiquantitatively. Low positivity was defined as positive immunoreactivity in &lt;50% of tumor glands, and high positivity was defined as positive immunoreactivity in ≥50% of tumor glands. Furthermore, clinicopathological features of patients were retrospectively reviewed. &lt;br&gt;&lt;b&gt;Results:&lt;/b&gt; High expression of CD133 was found in 47.8% of patients' CRC samples. In 69.6% of patients with metastatic lesions in visceral organs we found high expression of CD133. We found statistically significant differences in the expression of CD133 between patients with and without visceral metastatic lesions (P = 0.0153), between patients with a different T category (P = 0.0119), N status (P = 0.0066) and grade (G) (P = 0.0115). Our results showed that the stage of disease has the greatest impact on expression of CD133 (P &lt; 0.00001). &lt;br&gt;&lt;b&gt;Conclusion:&lt;/b&gt; High expression of CD133 is a useful marker for prediction of the clinically aggressive type of CRC and can be routinely implemented in standard pathohistological diagnostics.

High expression of tumor susceptibility gene 101 (TSG101) is associated with more aggressive behavior in colorectal carcinoma

INTRODUCTION

Identification of genetic determinants such as exosomal content that drives progression and metastasis of colorectal cancer (CRC) has received considerable attention. The present study aims to identify a suitable biomarker in CRC tissues and exosomes based on bioinformatics data to evaluate its expression patterns in CRC tissues as well as its clinicopathological significance.

MATERIALS AND METHODS

Protein-protein interaction (PPI) network and enrichment analysis were applied to identify up-regulated genes that contributed in CRC exosomes to select the marker. The expression patterns and clinical significance of selected exosomal marker were evaluated in tissue microarrays (TMAs) of 445 CRC tumors and 39 adjacent normal tissues using immunohistochemistry method.

RESULTS

Based on bioinformatics data, TSG101 gene was prominent amongst the tumor tissues and exosomes. Expression of TSG101 was significantly up-regulated in tumor cells compared to adjacent normal tissues (p-value = 0.04). Moreover, higher expressions of TSG101 (cytoplasmic and nuclear) were significantly associated with tumor differentiation (p-value = 0.042) and distant metastasis (p-value = 0.027). A significant association was found in the cytoplasmic expression of TSG101 between well and moderate tumor differentiation (p-value = 0.005) as well as moderate and poor differentiation (p-value = 0.050).

CONCLUSION

These findings indicate that the exploration of crosstalk between exosome content and CRC may be valuable for the development of novel exosomal biomarkers. Increased expression of TSG101, as a promising exosome marker, is more associated with more aggressive tumor behaviors, metastasis, and progression of CRC, which paves the way for therapeutic strategies and CRC management. However, further investigations are warranted to clarify the molecular mechanisms of TSG101 in CRC.

Differential inhibition of gelatinase activity in human colon adenocarcinoma cells by Aloe vera and Aloe arborescens extracts

BACKGROUND

Aloe's reported bioactivities (anticancer, anti-inflammatory and wound healing) suggest they might inhibit a subgroup of matrix metalloproteinases (MMPs) called gelatinases (MMP-2 and MMP-9). The goal of the present study was to compare the MMP inhibitory potential of two Aloe species, A. vera and A. arborescens.

METHODS

Different types of extraction were tested and specific bioactive compounds were quantified. Cancer cell invasion inhibitory activities were measured in vitro using the wound healing assay in human colon cancer cells (HT29). Effects on gelatinase activities were further assessed by dye-quenched gelatin and gelatin zymography.

RESULTS

Different types of extraction yielded significantly different levels of bioactivities and of bioactive compounds, which might be due to a greater amount of extractable bioactive compounds such as anthraquinones. Both A. arborescens and A. vera have potential as inhibitory agents in cancer cell proliferation via MMP-9 and MMP-2 enzymatic activity inhibition, being able to reduce colon cancer cell proliferation and migration but A. arborescens showed to be a more effective inhibitor of cancer cell migration than A. vera.

CONCLUSION

This work opens novel perspectives on the mode of action of Aloe species in cancer cell migration and may provide clues as to why there are so many conflicting results on Aloe's activities.

Blockade of EIF5A hypusination limits colorectal cancer growth by inhibiting MYC elongation

Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APCMin/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy.

Interplay between APC and ALDH1B1 in a newly developed mouse model of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer mortality worldwide. Mutations in the adenomatous polyposis coli (APC) gene are pivotal in colorectal tumorigenesis. Recently, we demonstrated that aldehyde dehydrogenase 1B1 (ALDH1B1) knockdown dramatically reduced colon tumor growth in a mouse xenograft model. The purpose of the present preliminary study is to examine the effect of loss of ALDH1B1 in CRC development in an inducible colon-specific Apc mouse model.

METHODS

Apc^W/FCdx2^ERT2-Cre mice develop uni-allelic inactivation of Apc specifically in colon epithelial cells following tamoxifen treatment. Aldh1b1^-/- KO mice were crossed with Apc^W/FCdx2^ERT2-Cre mice. Six-month-old male Apc^W/FCdx2^ERT2-Cre/Aldh1b1^-/-, and Apc^W/FCdx2^ERT2-Cre/Aldh1b1^+/+ mice were treated with tamoxifen (50 mg/kg, i.p.) for three consecutive days. Apc^W/F/Aldh1b1^-/- and Apc^W/F/Aldh1b1^+/+ mice were treated with corn oil (i.e., tamoxifen vehicle control) for three consecutive days. Eighteen days later, mice were sacrificed and their colons examined microscopically, macroscopically and histologically for the presence of adenoma.

RESULTS

All Apc^W/FCdx2^ERT2-Cre/Aldh1b1^+/+ and Apc^W/FCdx2^ERT2-Cre/Aldh1b1^-/- mice treated with tamoxifen developed colorectal adenoma. The Apc^W/FCdx2^ERT2-Cre/Aldh1b1^-/- mice showed a significant decrease in the total volume of all ileal and colonic adenomas, and decreased incidence of large colonic adenoma compared to Apc^W/FCdx2^ERT2-Cre/Aldh1b1^+/+ mice. Immunohistochemical analysis of p53 and β-catenin showed a trend toward decreased expression score in colonic adenomas of Apc^W/FCdx2^ERT2-Cre/Aldh1b1^-/- mice.

CONCLUSION

The present preliminary study suggests that deletion of ALDH1B1 may protect against the full development of colorectal cancer. Further mechanistic studies are required to elucidate how ALDH1B1 contributes for colorectal cancer.

FOXD3, frequently methylated in colorectal cancer, acts as a tumor suppressor and induces tumor cell apoptosis under ER stress via p53

Forkhead box D3 (FOXD3), an important member of the forkhead box transcription factor family, has many biological functions. However, the role and signaling pathways of FOXD3 in colorectal cancer (CRC) are still unclear. We examined FOXD3 expression and methylation in normal colon mucosa, CRC cell lines and primary tumors by reverse transcription–polymerase chain reaction, methylation-specific PCR and bisulfite genomic sequencing. We also evaluated its tumor-suppressive function by examining its modulation of apoptosis under endoplasmic reticulum (ER) stress in CRC cells. The FOXD3 target signal pathway was identified by western blotting, immunofluorescence and chromatin immunoprecipitation. We found that FOXD3 was frequently methylated and silenced in CRC cell lines and was downregulated in CRC tissues compared with paired adjacent non-tumor tissues. Meanwhile, low FOXD3 protein expression was significantly correlated with poor histopathological grading, lymph node metastasis and poor prognosis of patients, indicating its potential as a tumor marker that may be of potential value as a therapeutic target for CRC. Moreover, restoration of FOXD3 expression inhibited the proliferation and migration of tumor cells. FOXD3 also increased mitochondrial apoptosis through the unfolded protein response under ER stress. Furthermore, we found that FOXD3 could bind directly to the promoter of p53 and enhance its expression. Knockdown of p53 impaired the effect of apoptosis induced by FOXD3. In conclusion, we showed for the first time that FOXD3, which is frequently methylated in CRC, acted as a tumor suppressor inducing tumor cell apoptosis under ER stress via p53.

Development and Characterization of a Genetic Mouse Model of KRAS Mutated Colorectal Cancer

Patients with KRAS mutated colorectal cancer (CRC) represent a cohort with unmet medical needs, with limited options of FDA-approved therapies. Representing 40-45% of all CRC patients, they are considered ineligible to receive anti-EGFR monoclonal antibodies that have added a significant therapeutic benefit for KRAS wild type CRC patients. Although several mouse models of CRC have been developed during the past decade, one genetically resembling the KRAS mutated CRC is yet to be established. In this study C57 BL/6 mice with truncated adenomatous polyposis coli (APC) floxed allele was crossed with heterozygous KRAS floxed outbred mice to generate an APCf/f KRAS+/f mouse colony. In another set of breeding, APC floxed mice were crossed with CDX2-Cre-ERT2 mice and selected for APCf/f CDX2-Cre-ERT2 after the second round of inbreeding. The final model of the disease was generated by the cross of the two parental colonies and viable APC f/f KRAS +/f CDX2-Cre-ERT2 (KPC: APC) were genotyped and characterized. The model animals were tamoxifen (TAM) induced to generate tumors. Micro-positron emission tomography (PET) scan was used to detect and measure tumor volume and standard uptake value (SUV). Hematoxylin and eosin (H&E) staining was performed to establish neoplasm and immunohistochemistry (IHC) was performed to determine histological similarities with human FFPE biopsies. The MSI/microsatellite stable (MSS) status was determined. Finally, the tumors were extensively characterized at the molecular level to establish similarities with human CRC tumors. The model KPC: APC animals are conditional mutants that developed colonic tumors upon induction with tamoxifen in a dose-dependent manner. The tumors were confirmed to be malignant within four weeks of induction by H&E staining and higher radioactive [18F] fluoro-2-deoxyglucose (FDG) uptake (SUV) in micro-PET scan. Furthermore, the tumors histologically and molecularly resembled human colorectal carcinoma. Post tumor generation, the KPC: APC animals died of cachexia and rectal bleeding. Implications: This model is an excellent preclinical platform to molecularly characterize the KRAS mutated colorectal tumors and discern appropriate therapeutic strategies to improve disease management and overall survival.

Alterations in folate-dependent one-carbon metabolism as colon cell transition from normal to cancerous

Folate-dependent one-carbon cycle metabolism (FOCM) plays a critical role in maintaining genomic stability through regulating DNA biosynthesis, repair and methylation. Folate metabolites as well as other metabolites in the FOCM are hypothesized to be altered when cells transition from normal to cancerous state. Using cells at different stages in their development into colorectal cancer, the FOCM metabolites were profiled as an effort to phenotype the cells, and the metabolite levels were compared to the expressions of related genes. Here, we investigate whether there is a correlation between the metabolite levels, DNA methylation levels and the expression of the related genes that drive the levels of these metabolites. Using CRL1459, APC10.1, HCT116 and Caco-2, we show for the first time that FOCM metabolites correlate with the gene expression patterns. These differences follow a trend that may facilitate distinguishing colon cells at the different stages as they transition into cancerous state. The folate distribution and methionine levels were found to be key in determining the staging of the colon cells in CRC development. Also, expression of CBS, MTRR and MAT genes may facilitate distinguishing between untransformed and transformed colon cells.

The emergence of melatonin in oncology: Focus on colorectal cancer

Within the last few decades, melatonin has increasingly emerged in clinical oncology as a naturally occurring bioactive molecule with substantial anticancer properties and a pharmacological profile optimal for joining the currently available pharmacopeia. In addition, extensive experimental data shows that this chronobiotic agent exerts oncostatic effects throughout all stages of tumor growth, from initial cell transformation to mitigation of malignant progression and metastasis; additionally, melatonin alleviates the side effects and improves the welfare of radio/chemotherapy-treated patients. Thus, the support of clinicians and oncologists for the use of melatonin in both the treatment and proactive prevention of cancer is gaining strength. Because of its epidemiological importance and symptomatic debut in advanced stages of difficult clinical management, colorectal cancer (CRC) is a preferential target for testing new therapies. In this regard, the development of effective forms of clinical intervention for the improvement of CRC outcome, specifically metastatic CRC, is urgent. At the same time, the need to reduce the costs of conventional anti-CRC therapy results is also imperative. In light of this status quo, the therapeutic potential of melatonin, and the direct and indirect critical processes of CRC malignancy it modulates, have aroused much interest. To illuminate the imminent future on CRC research, we focused our attention on the molecular mechanisms underlying the multiple oncostatic actions displayed by melatonin in the onset and evolution of CRC and summarized epidemiological evidence, as well as in vitro, in vivo and clinical findings that support the broadly protective potential demonstrated by melatonin.

Association between oncogenic RAS mutation and radiologic-pathologic findings in patients with primary rectal cancer

Background

To evaluate the association between various radiologic-pathologic findings and oncogenic Kirsten-ras (KRAS) mutation in patients with primary rectal cancer.

Methods

Seventy-five patients with primary rectal cancer who had undergone rectal magnetic resonance imaging (MRI) were included. The rectal MRI consisted of T2-weighted images in three planes, pre- and post-contrast-enhanced T1-weighted images, and axial diffusion-weighted images (b factors, 0, 1,000 s/mm²). Two radiologists reviewed the MRI scans and measured the axial and longitudinal tumor lengths (LTLs), apparent diffusion coefficient (ADC), and relative contrast enhancement [signal intensity (SI) difference of tumor on pre- and post-contrast T1WI/SI of tumor on pre-contrast T1WI]. The associations among the qualitative data (tumor stage, node stage, lymphatic invasion, venous invasion, and perineural invasion), quantitative data (tumor length, ADC, relative contrast enhancement) and KRAS mutations were statistically analyzed by Fisher's exact test for the qualitative data and by the Mann-Whitney U test for the quantitative data. An area under receiver operating characteristic curve (AUC) was considered as the diagnostic performance for the prediction of KRAS mutation. Molecular-biologic results served as the reference standard.

Results

The ratio of axial to LTL in the KRAS-mutant group (n=41) was higher than that in the wild-type group (n=34) (0.29±0.15; 0.22±0.08, P=0.0117). The AUC was 0.640 (95% CI, 0.520 to 0.747, P=0.0292) with an estimated maximum accuracy of 64%. The mean ADC of the mutant group was not significantly different from that of the wild-type group [(0.95±0.17)×10^-3 mm²/s; (0.96±0.17)×10^-3 mm²/s, P=0.6505]. The relative contrast enhancement showed no significant difference between the two groups (1.66±0.93, 1.35±0.84, P=0.1581). The other qualitative findings also did not show any significant difference (P>0.05).

Conclusions

The ratio of axial to LTL showed a significant difference according to KRAS mutation in patients with primary rectal cancer. However, it showed a low accuracy of 64% for prediction of KRAS mutation.

Radiomics in Oncological PET/CT: Clinical Applications

18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is widely used for staging, evaluating treatment response, and predicting prognosis in malignant diseases. FDG uptake and volumetric PET parameters such as metabolic tumor volume have been used and are still used as conventional PET parameters to assess biological characteristics of tumors. However, in recent years, additional features derived from PET images by computational processing have been found to reflect intratumoral heterogeneity, which is related to biological tumor features, and to provide additional predictive and prognostic information, which leads to the concept of radiomics. In this review, we focus on recent clinical studies of malignant diseases that investigated intratumoral heterogeneity on PET/CT, and we discuss its clinical role in various cancers.

Epigenomic and Functional Characterization of Junctophilin 3 (JPH3) as a Novel Tumor Suppressor Being Frequently Inactivated by Promoter CpG Methylation in Digestive Cancers

Junctophilin (JPH) proteins stabilize junctional membrane complexes between plasma membrane and endoplasmic reticulum, also implicated in some human diseases. JPH3 mutations are linked to Huntington's disease-like 2 syndrome. Through epigenomic study of a colon cancer cell line pair (HCT116 and DKO), we identified JPH3 as a methylated novel tumor suppressor gene (TSG) candidate at 16q24. We further studied its epigenetic alterations and functions in digestive tumorigenesis. JPH3 expression at the RNA level was found to be frequently silenced or reduced in colorectal and gastric cancers due to its promoter CpG methylation, which is associated with tumor progression and poor survival of digestive cancer patients. Ectopic expression of JPH3 inhibited tumor cell growth in vitro and in vivo. JPH3 expression upregulated the cytosolic Ca²⁺ levels, and unfolded protein response gene expression upon endoplasmic reticulum stress. JPH3 also induced calpain activation and subsequent mitochondrial membrane depolarization and cell apoptosis. Thus, JPH3 was identified as a novel TSG methylated in colorectal and gastric tumors which promotes mitochondrial-mediated apoptosis, also as a potential metastasis and survival biomarker for digestive cancers.

Alteration of Leptin and Adiponectin in Multistep Colorectal Tumorigenesis

BACKGROUND

There is an established link between obesity related metabolic derangement and colorectal cancer development. Recently, we developed a metabolic-colorectal cancer risk score. In this follow-up study, we studied its association with colorectal neoplasm by measuring two major metabolic syndrome biomarkers, leptin and adiponectin.

OBJECTIVES

To evaluate the serum levels of leptin and adiponectin in patients with colorectal polyps and colorectal cancer and to determine any correlation with metabolic risk score.

RESULTS

In total, 130 individuals were studied: 30 controls without colonic pathology, 18 with colonic adenoma (CAP), and 82 with colorectal adenocarcinoma (CRC, 17 cases of T1-2 and 65 cases of T3-4). The metabolic risk scores in CAP and T1-2 CRC were higher than those in the controls and T3-4 CRC cases. There were no statistically significant differences in leptin levels among CAPs, CRCs, and controls. Both leptin and adiponectin levels reflected differences in body mass index and metabolic risk scores. Cases in the CAP group and early T-stage CRC groups had lower adiponectin levels (14.03 and 13.01 mg/ml, respectively) than the no polyps group (19.5mg/ml, p = 0.03). The average serum adiponectin level in the invasive cancer group (18.5 ng/ml) was comparable with that of the control group.

CONCLUSIONS

The level of serum adiponectin was positively correlated with the metabolic risk score. Decreased serum adiponectin was significantly associated with the development of colorectal adenoma and early stage colorectal carcinoma.

Dietary fibre for the prevention of recurrent colorectal adenomas and carcinomas

BACKGROUND

This is an update of the Cochrane review published in 2002.Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialised countries. Experimental evidence has supported the hypothesis that dietary fibre may protect against the development of CRC, although epidemiologic data have been inconclusive.

OBJECTIVES

To assess the effect of dietary fibre on the recurrence of colorectal adenomatous polyps in people with a known history of adenomatous polyps and on the incidence of CRC compared to placebo. Further, to identify the reported incidence of adverse effects, such as abdominal pain or diarrhoea, that resulted from the fibre intervention.

SEARCH METHODS

We identified randomised controlled trials (RCTs) from Cochrane Colorectal Cancer's Specialised Register, CENTRAL, MEDLINE and Embase (search date, 4 April 2016). We also searched ClinicalTrials.gov and WHO International Trials Registry Platform on October 2016.

SELECTION CRITERIA

We included RCTs or quasi-RCTs. The population were those having a history of adenomatous polyps, but no previous history of CRC, and repeated visualisation of the colon/rectum after at least two-years' follow-up. Dietary fibre was the intervention. The primary outcomes were the number of participants with: 1. at least one adenoma, 2. more than one adenoma, 3. at least one adenoma greater than or equal to 1 cm, or 4. a new diagnosis of CRC. The secondary outcome was the number of adverse events.

DATA COLLECTION AND ANALYSIS

Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. We used risk ratios (RR) and risk difference (RD) with 95% confidence intervals (CI) to measure the effect. If statistical significance was reached, we reported the number needed to treat for an additional beneficial outcome (NNTB) or harmful outcome (NNTH). We combined the study data using the fixed-effect model if it was clinically, methodologically, and statistically reasonable.

MAIN RESULTS

We included seven studies, of which five studies with 4798 participants provided data for analyses in this review. The mean ages of the participants ranged from 56 to 66 years. All participants had a history of adenomas, which had been removed to achieve a polyp-free colon at baseline. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. The comparators were low-fibre (2 to 3 g per day), placebo, or a regular diet. The combined data showed no statistically significant difference between the intervention and control groups for the number of participants with at least one adenoma (5 RCTs, n = 3641, RR 1.04, 95% CI 0.95 to 1.13, low-quality evidence), more than one adenoma (2 RCTs, n = 2542, RR 1.06, 95% CI 0.94 to 1.20, low-quality evidence), or at least one adenoma 1 cm or greater (4 RCTs, n = 3224, RR 0.99, 95% CI 0.82 to 1.20, low-quality evidence) at three to four years. The results on the number of participants diagnosed with colorectal cancer favoured the control group over the dietary fibre group (2 RCTS, n = 2794, RR 2.70, 95% CI 1.07 to 6.85, low-quality evidence). After 8 years of comprehensive dietary intervention, no statistically significant difference was found in the number of participants with at least one recurrent adenoma (1 RCT, n = 1905, RR 0.97, 95% CI 0.78 to 1.20), or with more than one adenoma (1 RCT, n = 1905, RR 0.89, 95% CI 0.64 to 1.24). More participants given ispaghula husk group had at least one recurrent adenoma than the control group (1 RCT, n = 376, RR 1.45, 95% CI 1.01 to 2.08). Other analyses by types of fibre intervention were not statistically significant. The overall dropout rate was over 16% in these trials with no reasons given for these losses. Sensitivity analysis incorporating these missing data shows that none of the results can be considered as robust; when the large numbers of participants lost to follow-up were assumed to have had an event or not, the results changed sufficiently to alter the conclusions that we would draw. Therefore, the reliability of the findings may have been compromised by these missing data (attrition bias) and should be interpreted with caution.

AUTHORS' CONCLUSIONS

There is a lack of evidence from existing RCTs to suggest that increased dietary fibre intake will reduce the recurrence of adenomatous polyps in those with a history of adenomatous polyps within a two to eight year period. However, these results may be unreliable and should be interpreted cautiously, not only because of the high rate of loss to follow-up, but also because adenomatous polyp is a surrogate outcome for the unobserved true endpoint CRC. Longer-term trials with higher dietary fibre levels are needed to enable confident conclusion.

Prevalence and Risk Factors of Gastric Adenoma and Gastric Cancer in Colorectal Cancer Patients

Background/Aims. To evaluate the incidence of gastric adenoma and gastric cancer in colorectal cancer patients, as well as the clinicopathological features that affect their incidence. Methods. Among patients who underwent surgery after being diagnosed with colorectal cancer between January 2004 and December 2013 at Chungnam National University Hospital, 142 patients who underwent follow-up upper gastrointestinal endoscopy were assigned to the patient group. The control group included 426 subjects randomly selected. The patient group was subdivided into two: one that developed gastric adenoma or cancer and one that did not. Clinicopathological characteristics were compared between these groups. Results. In total, 35 (24.6%) colorectal cancer patients developed a gastric adenoma or gastric cancer, which was higher than the number in the control group (20 [4.7%] patients; p < 0.001). Age, alcohol history, and differentiation of colorectal cancer were associated with higher risks of gastric adenoma or gastric cancer, with odds ratios of 1.062, 6.506, and 5.901, respectively. Conclusions. In colorectal cancer patients, screening with upper gastrointestinal endoscopy is important, even if no lesions are noted in the upper gastrointestinal tract at colorectal cancer diagnosis. Endoscopic screening is particularly important with increasing age, history of alcohol consumption, and poor cancer differentiation.

Role of neutral ceramidase in colon cancer

Alterations in sphingolipid metabolism, especially ceramide and sphingosine 1-phosphate, have been linked to colon cancer, suggesting that enzymes of sphingolipid metabolism may emerge as novel regulators and targets in colon cancer. Neutral ceramidase (nCDase), a key enzyme in sphingolipid metabolism that hydrolyzes ceramide into sphingosine, is highly expressed in the intestine; however, its role in colon cancer has not been defined. Here we show that molecular and pharmacological inhibition of nCDase in colon cancer cells increases ceramide, and this is accompanied by decreased cell survival and increased apoptosis and autophagy, with minimal effects on noncancerous cells. Inhibition of nCDase resulted in loss of β-catenin and inhibition of ERK, components of pathways relevant for colon cancer development. Furthermore, inhibition of nCDase in a xenograft model delayed tumor growth and increased ceramide while decreasing proliferation. It is noteworthy that mice lacking nCDase treated with azoxymethane were protected from tumor formation. Taken together, these studies show that nCDase is pivotal for regulating initiation and development of colon cancer, and these data suggest that this enzyme is a suitable and novel target for colon cancer therapy.-García-Barros, M., Coant, N., Kawamori, T., Wada, M., Snider, A. J., Truman, J.-P., Wu, B. X., Furuya, H., Clarke, C. J., Bialkowska, A. B., Ghaleb, A., Yang, V. W., Obeid, L. M., Hannun, Y. A. Role of neutral ceramidase in colon cancer.

Effects of mutations in Wnt/β-catenin, hedgehog, Notch and PI3K pathways on GSK-3 activity-Diverse effects on cell growth, metabolism and cancer

Glycogen synthase kinase-3 (GSK-3) is a serine/threonine kinase that participates in an array of critical cellular processes. GSK-3 was first characterized as an enzyme that phosphorylated and inactivated glycogen synthase. However, subsequent studies have revealed that this moon-lighting protein is involved in numerous signaling pathways that regulate not only metabolism but also have roles in: apoptosis, cell cycle progression, cell renewal, differentiation, embryogenesis, migration, regulation of gene transcription, stem cell biology and survival. In this review, we will discuss the roles that GSK-3 plays in various diseases as well as how this pivotal kinase interacts with multiple signaling pathways such as: PI3K/PTEN/Akt/mTOR, Ras/Raf/MEK/ERK, Wnt/beta-catenin, hedgehog, Notch and TP53. Mutations that occur in these and other pathways can alter the effects that natural GSK-3 activity has on regulating these signaling circuits that can lead to cancer as well as other diseases. The novel roles that microRNAs play in regulation of the effects of GSK-3 will also be evaluated. Targeting GSK-3 and these other pathways may improve therapy and overcome therapeutic resistance.

Clinicopathologic features of gastric cancer with synchronous and metachronous colorectal cancer in Korea: are microsatellite instability and p53 overexpression useful markers for predicting colorectal cancer in gastric cancer patients?

BACKGROUND

A large-scale study was performed to identify the risk factors for developing synchronous and metachronous colorectal cancer (CRC) in gastric cancer (GC) patients, including microsatellite instability (MSI) and p53 overexpression.

METHODS

A total of 1041 GC patients who underwent endoscopic resection or surgery and underwent colonoscopy simultaneously or during surveillance for GC were consecutively enrolled. Clinicopathologic characteristics, MSI, and p53 overexpression were compared between the GC patients with and those without synchronous and metachronous CRC.

RESULTS

Of the 1041 patients, CRCs were detected in 67 (6.4 %) patients with GC. Forty-six (4.4 %) had synchronous CRC and 21 (2.0 %) had metachronous CRC. Univariate analysis indicated that age ≥63 years (P < 0.001), male sex (P = 0.005), and p53 overexpression (P = 0.040) were significantly associated with a higher incidence of CRC. However, body mass index, smoking, tumor location, tumor multiplicity, tumor histology, TNM stage, and MSI were not significantly associated with the incidence of CRC. Age ≥63 years (OR: 5.881; 95 % CI: 3.083-11.221; P < 0.001) and male sex (OR: 2.933; 95 % CI: 1.307-6.584; P = 0.009) were risk factors for CRC in GC patients according to multivariate analysis.

CONCLUSIONS

GC patients who are male and/or ≥63 years old are recommended to receive colonoscopy to detect CRC. MSI and p53 overexpression were not useful molecular markers for predicting CRC in GC.

In Hyperthermia Increased ERK and WNT Signaling Suppress Colorectal Cancer Cell Growth

Although neoplastic cells exhibit relatively higher sensitivity to hyperthermia than normal cells, hyperthermia has had variable success as an anti-cancer therapy. This variable outcome might be due to the fact that cancer cells themselves have differential degrees of sensitivity to high temperature. We hypothesized that the varying sensitivity of colorectal cancer (CRC) cells to hyperthermia depends upon the differential induction of survival pathways. Screening of such pathways revealed that Extracellular Signal-Regulated Kinase (ERK) signaling is augmented by hyperthermia, and the extent of this modulation correlates with the mutation status of V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS). Through clonal growth assays, apoptotic analyses and transcription reporter assays of CRC cells that differ only in KRAS mutation status we established that mutant KRAS cells are more sensitive to hyperthermia, as they exhibit sustained ERK signaling hyperactivation and increased Wingless/Integrated (WNT)/beta-catenin signaling. We propose that whereas increased levels of WNT and ERK signaling and a positive feedback between the two pathways is a major obstacle in anti-cancer therapy today, under hyperthermia the hyperinduction of the pathways and their positive crosstalk contribute to CRC cell death. Ascertaining the causative association between types of mutations and hyperthermia sensitivity may allow for a mutation profile-guided application of hyperthermia as an anti-cancer therapy. Since KRAS and WNT signaling mutations are prevalent in CRC, our results suggest that hyperthermia-based therapy might benefit a significant number, but not all, CRC patients.

(18)F-FDG PET/CT imaging in rectal cancer: relationship with the RAS mutational status

OBJECTIVE

Treating metastatic colorectal cancer with anti-EGFR monoclonal antibodies is recommended only for patients whose tumour does not harbour mutations of KRAS or NRAS. The aim of this study was to investigate the biology of rectal cancers and specifically to evaluate the relationship between fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) intensity and heterogeneity parameters and their mutational status.

METHODS

151 patients with newly diagnosed rectal cancer were included in this retrospective study. All patients underwent a baseline (18)F-FDG PET/CT within a median time interval of 27 days of tumour tissue sampling, which was performed before any treatment. Standardized uptake values (SUVs), volume-based parameters and texture analysis were studied. We retrospectively performed KRAS genotyping on codons 12, 13, 61, 117 and 146, NRAS genotyping on codons 12, 13 and 61 and BRAF on codon 600. Associations between PET/CT parameters and the mutational status were assessed using univariate and multivariate analysis.

RESULTS

83 (55%) patients had an RAS mutation: 74 KRAS and 9 NRAS, while 68 patients had no mutation (wild-type tumours). No patient had BRAF mutation. First-order features based on intensity histogram analysis were significantly associated with RAS mutations: maximum SUV (SUVmax) (p-value = 0.002), mean SUV (p-value = 0.006), skewness (p-value = 0.049), SUV standard deviation (p-value = 0.001) and SUV coefficient of variation (SUVcov) (p-value = 0.001). Both SUVcov and SUVmax showed an area under the curve of 0.65 with sensitivity of 56% and 69%, respectively, and specificity of 64% and 52%, respectively. None of the volume-based (metabolic tumour volume and total lesion glycolysis), nor local or regional textural features were associated with the presence of RAS mutations.

CONCLUSION

Although rectal cancers with KRAS or NRAS mutations display a significantly higher glucose metabolism than wild-type cancers, the accuracy of the currently proposed quantitative metrics extracted from (18)F-FDG PET/CT is not sufficiently high for playing a meaningful clinical role.

ADVANCES IN KNOWLEDGE

RAS-mutated rectal cancers have a significantly higher glucose metabolism. However, the accuracy of (18)F-FDG PET/CT quantitative metrics is not as such as the technique could play a clinical role.

ML264, A Novel Small-Molecule Compound That Potently Inhibits Growth of Colorectal Cancer

Colorectal cancer is one of the leading causes of cancer mortality in Western civilization. Studies have shown that colorectal cancer arises as a consequence of the modification of genes that regulate important cellular functions. Deregulation of the WNT and RAS/MAPK/PI3K signaling pathways has been shown to be important in the early stages of colorectal cancer development and progression. Krüppel-like factor 5 (KLF5) is a transcription factor that is highly expressed in the proliferating intestinal crypt epithelial cells. Previously, we showed that KLF5 is a mediator of RAS/MAPK and WNT signaling pathways under homeostatic conditions and that it promotes their tumorigenic functions during the development and progression of intestinal adenomas. Recently, using an ultrahigh-throughput screening approach we identified a number of novel small molecules that have the potential to provide therapeutic benefits for colorectal cancer by targeting KLF5 expression. In the current study, we show that an improved analogue of one of these screening hits, ML264, potently inhibits proliferation of colorectal cancer cells in vitro through modifications of the cell-cycle profile. Moreover, in an established xenograft mouse model of colon cancer, we demonstrate that ML264 efficiently inhibits growth of the tumor within 5 days of treatment. We show that this effect is caused by a significant reduction in proliferation and that ML264 potently inhibits the expression of KLF5 and EGR1, a transcriptional activator of KLF5. These findings demonstrate that ML264, or an analogue, may hold a promise as a novel therapeutic agent to curb the development and progression of colorectal cancer.

Radiation promotes colorectal cancer initiation and progression by inducing senescence-associated inflammatory responses

Proton radiotherapy is becoming more common since protons induce more precise DNA damage at the tumor site with reduced side effects to adjacent normal tissues. However, the long-term biological effects of proton irradiation in cancer initiation compared to conventional photon irradiation are poorly characterized. In this study, using a human familial adenomatous polyposis syndrome susceptible mouse model, we show that whole body irradiation with protons are more effective in inducing senescence-associated inflammatory responses (SIR) which are involved in colon cancer initiation and progression. After proton irradiation, a subset of SIR genes (Troy, Sox17, Opg, Faim2, Lpo, Tlr2 and Ptges) and a gene known to be involved in invasiveness (Plat), along with the senescence associated gene (P19Arf) are markedly increased. Following these changes loss of Casein kinase Iα (CKIα) and induction of chronic DNA damage and TP53 mutations are increased compared to x-ray irradiation. Proton irradiation also increases the number of colonic polyps, carcinomas and invasive adenocarcinomas. Pretreatment with the non-steroidal anti-inflammatory drug, CDDO-EA, reduces proton irradiation associated SIR and tumorigenesis. Thus, exposure to proton irradiation elicits significant changes in colorectal cancer initiation and progression that can be mitigated using CDDO-EA.

Expression of secreted phospholipase A2-Group IIA correlates with prognosis of gastric adenocarcinoma

The present study investigated the expression of secretory phospholipase A2-Group IIA (sPLA2-II) in gastric adenocarcinoma, in order to evaluate the correlation between sPLA2-II expression, and the clinicopathological features and prognosis of patients with gastric adenocarcinoma. Between January 2007 and April 2010, data were collected from 65 patients (44 males, 21 females; age range, 30-79 years; mean 66.7 ± 10.7 years). All patients exhibited a pathologically confirmed diagnosis of gastric adenocarcinoma. Endoscopic biopsy specimens of normal gastric mucosa from 11 of these patients were used as controls. Patients were subsequently followed-up at 3-month intervals, and survival data were recorded until April 2010. Expression of sPLA2-II in 65 gastric adenocarcinoma and 11 normal gastric mucosa specimens was evaluated via immunohistochemistry. A semi-quantitative method, consisting of evaluation of staining percentage and intensity, was utilized for immunohistochemical scoring, and the receiver operating characteristic curve method was applied to select a cut-off score for high and low sPLA2-II expression. The value of 8 was selected as the cut-off score, with maximum sensitivity and specificity. High sPLA2-II expression was observed in stage III/IV cases (83.3%; 40/48) and poorly differentiated cells (94.1%; 32/34), while sPLA2-II expression levels were observed to be significantly lower in stage I/II cases (52.9%; 9/17) and well and moderately differentiated cells (54.8%; 17/31; P=0.021 and P<0.001, respectively). There were no significant correlations observed between sPLA2-II expression and any other clinicopathological parameters, including gender, age, tumor diameter and Helicobacter pylori infection. Patients exhibiting low sPLA2-II expression experienced significantly improved overall survival (OS) and disease-free survival (DFS), compared with those exhibiting high sPLA2-II expression (P=0.043 and P=0.035, respectively). Multivariate analysis confirmed that high sPLA2-II expression may be an independent prognostic factor for OS [relative risk, 2.849; 95% confidence interval (CI), 1.088-7.459; P=0.033] and DFS (relative risk, 2.735; 95% CI, 1.104-6.776; P=0.030) in gastric adenocarcinoma. Therefore, sPLA2-II may be correlated with the histogenesis of gastric adenocarcinoma, and increased sPLA2-II expression may be an indicator of poor prognosis.

Surveillance for early stages of colon cancer: potentials for optimizing follow-up protocols

Background

Although several meta-analyses showed the positive effects of follow-up on the prognosis of colon cancer (CC), international guidelines are not in accordance on appropriate tests and their time frequency to optimize surveillance. Furthermore, stratified strategies based upon risk grading have not been implemented. This approach may be useful to rationalize resources.

Methods

From 2006, all patients operated for an early stage CC (I, IIA, IIB) according to the 7th edition of the AJCC-2010 classification entered in a prospective surveillance program in accordance to our local guidelines. Patients who underwent surgical resection after 2009 have been excluded to guarantee at least a 5-year follow-up. Classic histopathologic prognostic factors such as grade, T and N status, lymphatic and vascular invasion were assessed. Moreover, tumor budding and tumor-to-stroma proportion were evaluated.

Results

We had complete records of 196 patients. Distribution was as follows: 65 (33.2 %) in stage I, 122 (62.2 %) in stage IIA, and 9 (4.6 %) in stage IIB. Eleven patients (5.6 %) had a disease recurrence (local or distant). The median recurrence time was 20 months (range 6–48). Nine patients (82 %) had recurrence with 24 months, and 91 % were asymptomatic and detected by ultrasound or CT scan. According to the log-rank test, the risk factors with significant effect on the disease-free survival (DFS) were the number of lymph nodes <12 (p = 0.027) and the vascular invasion (p = 0.021), while for the overall (OS), only the vascular invasion was significant (p = 0.043). By the univariate and multivariate analyses, DSF was significantly lower in patients with less than 12 nodes removed, with vascular invasion, and with left of double cancer. OS was negatively affected only by vascular invasion despite the hazard ratios were similar to DSF. Stage IIB was associated with a threefold-increased risk of reduced OS and DSF.

Conclusions

Stages I and IIA appear to behave similarly and should be considered as true early stages. The detection of fibrosis and budding do not seem to add valuable information for prognosis. In early CC stages, the surveillance program should be maximized within the first two years.

Molecular Alterations of Colorectal Cancer with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an important etiologic factor in the development of colorectal cancer (CRC). The risk of CRC begins to increase 8 or 10 years after the diagnosis of IBD. This type of cancer is called colitis-associated CRC (CA-CRC). The molecular pathogenesis of inflammatory epithelium might play a critical role in the development of CA-CRC. Genetic alterations detected in CA-CRC such as genetic mutations, microsatellite instability, and DNA hypermethylation are also recognized in sporadic CRC; however, there are differences in the timing and frequency of molecular events between CA-CRC and sporadic CRC. Interaction between gene-environmental factors, including inflammation, lifestyle, psychological stress, and prior appendectomy, might be associated with the etiopathology of IBD. The mucosal inflammatory mediators, such as oxidant stress, free radicals, and chemokines, may cause the genetic alterations. Understanding the molecular mechanisms of CA-CRC might be important to develop clinical efficacies for patients with IBD. This review discusses the molecular characteristics of CA-CRC, especially ulcerative colitis-associated CRC, including clinical features, signaling pathways, and interactions between genetic alterations and environment involved in inflammatory carcinogenesis.

Chlorinated Water Modulates the Development of Colorectal Tumors with Chromosomal Instability and Gut Microbiota in Apc-Deficient Mice

The gastrointestinal tract is continuously exposed to a variety of chemicals and commensal bacteria. Recent studies have shown that changes in gut microbial populations caused by chlorine or other chemicals in the drinking water influence the development of human colorectal cancer, although the mechanism of tumorigenesis in the gut epithelium is obfuscated by the diversity of microflora and complexity of the tumor microenvironment. In this regard, mouse models that recapitulate human colorectal cancer are an invaluable tool. In this study, we used two conditional adenomatous polyposis coli (Apc) knockout mouse models to investigate the effect of chlorinated water on tumorigenesis in the digestive tract. Mice with colon-specific carcinoma--caused by either chromosomal (CDX2P 9.5-NLS Cre;Apc(+/flox), abbreviated to CPC;Apc) or microsatellite (CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox)) instability, respectively--were administered chlorinated (10.0 mg/L chlorine) or tap (0.7 mg/L chlorine) water and evaluated for colon polyp formation. In CPC;Apc mice given chlorinated drinking water, tumors tended to develop in the colon, whereas in those that drank tap water, tumors were mostly observed in the small intestine. There was no difference in the rate of tumor formation of CDX2P9.5-G19Cre;Apc(flox/flox) and CDX2P9.5-G22Cre;Apc(flox/flox) mice consuming chlorinated as compared to tap water, suggesting that microsatellite instability in the Apc gene does not significantly affect tumorigenesis. Chlorinated water altered the enteric environment by reducing the fecal populations of the obligatory anaerobes Clostridium perfringens and C. difficile, as well as species belonging to the Atopobium cluster, including Enterobacteriaceae and Staphylococcus sp., which was associated with colon tumorigenesis in CPC;Apc mice. These results suggest that differences in tumorigenesis among CPC;Apc mice consuming chlorinated versus tap water may be due to differences in gastrointestinal commensal populations.

RNA sequencing supports distinct reactive oxygen species-mediated pathways of apoptosis by high and low size mass fractions of Bay leaf (Lauris nobilis) in HT-29 cells

Anti-proliferative and pro-apoptotic effects of Bay leaf (Laurus nobilis) in mammalian cancer and HT-29 adenocarcinoma cells have been previously attributed to effects of polyphenolic and essential oil chemical species. Recently, we demonstrated differentiated growth-regulating effects of high (HFBL) versus low molecular mass (LFBL) aqueous fractions of bay leaf and now confirm by comparative effects on gene expression, that HFBL and LFBL suppress HT-29 growth by distinct mechanisms. Induction of intra-cellular lesions including DNA strand breakage by extra-cellular HFBL, invoked the hypothesis that iron-mediated reactive oxygen species with capacity to penetrate cell membrane, were responsible for HFBL-mediated effects, supported by equivalent effects of HFBL in combination with γ radiation. Activities of HFBL and LFBL were interpreted to reflect differentiated responses to iron-mediated reactive oxygen species (ROS), occurring either outside or inside cells. In the presence of LFBL, apoptotic death was relatively delayed compared with HFBL. ROS production by LFBL mediated p53-dependent apoptosis and recovery was suppressed by promoting G1/S phase arrest and failure of cellular tight junctions. In comparison, intra-cellular anti-oxidant protection exerted by LFBL was absent for extra-cellular HFBL (likely polysaccharide-rich), which potentiated more rapid apoptosis by producing DNA double strand breaks. Differentiated effects on expression of genes regulating ROS defense and chromatic condensation by LFBL versus HFBL, were observed. The results support ferrous iron in cell culture systems and potentially in vivo, can invoke different extra-cellular versus intra-cellular ROS-mediated chemistries, that may be regulated by exogenous, including dietary species.

Colorectal cancer in iran: molecular epidemiology and screening strategies

Purpose. The increasing incidence of colorectal cancer (CRC) in the past three decades in Iran has made it a major public health burden. This study aimed to report its epidemiologic features, molecular genetic aspects, survival, heredity, and screening pattern in Iran. Methods. A comprehensive literature review was conducted to identify the relevant published articles. We used medical subject headings, including colorectal cancer, molecular genetics, KRAS and BRAF mutations, screening, survival, epidemiologic study, and Iran. Results. Age standardized incidence rate of Iranian CRCs was 11.6 and 10.5 for men and women, respectively. Overall five-year survival rate was 41%, and the proportion of CRC among the younger age group was higher than that of western countries. Depending on ethnicity, geographical region, dietary, and genetic predisposition, mutation genes were considerably diverse and distinct among CRCs across Iran. The high occurrence of CRC in records of relatives of CRC patients showed that family history of CRC was more common among young CRCs. Conclusion. Appropriate screening strategies for CRC which is amenable to early detection through screening, especially in relatives of CRCs, should be considered as the first step in CRC screening programs.

Identification of nitric oxide-releasing derivatives of oleanolic acid as potential anti-colon cancer agents

NO-releasing hybrid 6 regulates colon cancer-related signaling pathways, exhibiting potent anti-colon cancer activity in vitro and in vivo.

Dietary cocoa protects against colitis-associated cancer by activating the Nrf2/Keap1 pathway

Colorectal cancer (CRC) is the third most common malignancy in males and the second most common cancer worldwide. Chronic colonic inflammation is a known risk factor for CRC. Cocoa contains many polyphenolic compounds that have beneficial effects in humans. The objective of this study is to explore the antioxidant properties of cocoa in the mouse model of azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colitis-associated cancer, focusing on the activation of Nrf2 signaling. Mice were treated with AOM/DSS and randomized to receive either a control diet or a 5 and 10% cocoa diet during the study period. On day 62 of the experiment, the entire colon was processed for biochemical and histopathological examination and further evaluations. Increased levels of malondialdehyde (MDA) were observed in AOM/DSS-induced mice; however, subsequent administration of cocoa decreased the MDA. Enzymatic and nonenzymatic antioxidants, such as superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase, were decreased in the AOM/DSS mice. Cocoa treatment increases the activities/levels of enzymatic and nonenzymatic antioxidants. Inflammatory mediators, such as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, were elevated during AOM/DSS-induction, and treatment with 5 and 10% cocoa effectively decreases the expression of iNOS and COX-2. The NF-E2-related factor 2 and its downstream targets, such as NQO1 and UDP-GT, were increased by cocoa treatment. The results of our study suggest that cocoa may merit further clinical investigation as a chemopreventive agent that helps prevent CAC.

Cross-species analysis of genetically engineered mouse models of MAPK-driven colorectal cancer identifies hallmarks of the human disease

Effective treatment options for advanced colorectal cancer (CRC) are limited, survival rates are poor and this disease continues to be a leading cause of cancer-related deaths worldwide. Despite being a highly heterogeneous disease, a large subset of individuals with sporadic CRC typically harbor relatively few established 'driver' lesions. Here, we describe a collection of genetically engineered mouse models (GEMMs) of sporadic CRC that combine lesions frequently altered in human patients, including well-characterized tumor suppressors and activators of MAPK signaling. Primary tumors from these models were profiled, and individual GEMM tumors segregated into groups based on their genotypes. Unique allelic and genotypic expression signatures were generated from these GEMMs and applied to clinically annotated human CRC patient samples. We provide evidence that a Kras signature derived from these GEMMs is capable of distinguishing human tumors harboring KRAS mutation, and tracks with poor prognosis in two independent human patient cohorts. Furthermore, the analysis of a panel of human CRC cell lines suggests that high expression of the GEMM Kras signature correlates with sensitivity to targeted pathway inhibitors. Together, these findings implicate GEMMs as powerful preclinical tools with the capacity to recapitulate relevant human disease biology, and support the use of genetic signatures generated in these models to facilitate future drug discovery and validation efforts.

Colonoscopy as a tool for evaluating colorectal tumor development in a mouse model

PURPOSE

A sporadic colon cancer mouse model with conditional mutations in adenomatous polyposis coli (Apc) is biologically relevant for human colorectal cancer (CRC). This study aimed to determine the utility and limitations of colonoscopy for evaluating colon tumors in this mouse model.

METHODS

We compared the estimates of location, size, and miss rate of tumors detected during colonoscopy with those determined by necropsy. Sixty-six CPC-Apc mice originating from Apc (F/wt) mice harbor a Cdx2-Cre transgene in which colorectal tumorigenesis was driven by Apc allelic loss. The sensitivity and specificity of colonoscopy for detecting tumors in a mouse CRC model were investigated.

RESULTS

A strong positive correlation was found between tumor location as measured by colonoscopy and the location determined by necropsy (p < 0.001). A total of 120 tumors were graded during colonoscopy (grades 1-5: 0, 8, 20, 27, and 65 lesions, respectively), and a strong positive correlation was found between the tumor grade determined by colonoscopy and size measured by necropsy (grades 2-5: 2.08, 2.98, 4.02, and 5.09 mm, respectively; p < 0.005). Although the miss rate was 47.1 %, most of the missed tumors (96 %) were in close proximity (within 5 mm) of another tumor.

CONCLUSIONS

A colonoscopic method for the reliable measurement of colorectal tumors in vivo has been established. The application of this technique to mouse models of colon carcinogenesis will provide a better understanding of the dynamics of tumor growth.