Colon Adenoma Patients Research Articles

Significance of long non-coding RNA IFNG-AS1 in the progression and clinical prognosis in colon adenocarcinoma

ABSTRACT Colon adenocarcinoma originates from adenoma and triggers serious healthy burdensome. lncRNAs develop a crucial role in the progression of colorectal carcinoma. In this study, we aimed to investigate the clinical value and potential role of lncRNA interferon (IFN) gamma antisense RNA 1 (IFNG-AS1) in colon adenocarcinoma. This study enrolled 95 colorectal adenoma patients, 128 colorectal adenocarcinoma patients, and 88 healthy individuals. The serum, tissue IFNG-AS1 expression levels were explored by real-time quantitative reverse transcription-PCR (RT-qPCR) assay. The receiver operator characteristic curve and Kaplan-Meier method were used to assess the clinical significance of IFNG-AS1. The chi-square test was used to analyze the association between tissue IFNG-AS1 and clinical characteristics. Functional experiments were conducted to delve into the effects of IFNG-AS1 on cellular activities (cell viability/migration/invasion). The target miRNA of IFNG-AS1 was also explored. IFNG-AS1 expression in both serum and tissue samples was elevated in patients. Serum IFNG-AS1 could diagnose colon adenoma and adenocarcinoma patients from the healthy control. High tissue IFNG-AS1 was correlated with several clinical characteristics and a shorter overall survival time. Silence of IFNG-AS1 could be available for repressing cellular capacities via the sponge to miR-627-3p. IFNG-AS1 was rised in colon adenocarcinoma and it was relevant to tumor size, TNM stage, and poor prognosis of patients. Beyond that, downregulated expression of IFNG-AS1 may repress malignant progression of colon adenocarcinoma by regulating miR-627-3p. IFNG-AS1 might be a potential diagnosis or prognosis predictor for colon adenocarcinoma patients.

Abstract 2578: Serum analysis of obese and diabetic African American colon adenoma patients reveals novel potential miRNA markers of carcinogenesis

Abstract We have previously demonstrated that Adiponectin, leptin, TNF-alpha, and IGF-1 were highly prevalent in patients with colon adenomas when compared to healthy individuals. In the present study, we aimed to establish specific miRNA signatures in obese and diabetic African American patients developing colorectal adenomas. Patients & Methods: Serum samples from 72 individuals (18 normal, 18 adenoma-obese, 18 adenoma-diabetic, and 18 adenoma-obese-diabetic) seen at Howard University Hospital were collected. All selected patients were age and gender-matched across the 4 groups. Serum RNA extracts were used for library preparation and sequencing on an Illumina NextSeq 500 using SR75 High Output kit. Sequencing data were processed through the miasma-Seq pipeline. CutAdapt was used to trim Illumina adapters and remove reads that were less than 15 bp long. Reads were aligned to the UCSC hg38 human genome reference sequence using Bowtie2. Annotation data in the form of a GFF file from mirBase was used to count the number of reads falling in each hairpin locus. To estimate differential expression between different groups of samples, the count data were used in the DESeq2 R package and the 4 patient groups comparisons were performed. MiRNAs with statistically significant (p < 0.05) expression difference from normal and log 2 FC > 2 and/or < -2 were selected for functional analysis using Ingenuity Pathway Analysis (IPA). Results: Comparisons to normals revealed that 11 miRNAs [hsa-mir-34a, hsa-mir-133a-1, hsa-mir-127, hsa-mir-99b, hsa-mir-485, hsa-mir-378d-2, hsa-mir-3168, hsa-mir-3679, hsa-mir-378e, hsa-mir-4635, hsa-mir-6509] were down-regulated in Adenoma-Obese; 3 miRNAs were down-regulated [hsa-mir-1228, hsa-mir-3912, hsa-mir-4665] and 3 up-regulated [hsa-mir-455, hsa-mir-219b, hsa-mir-8072 ] in Adenoma-Diabetic patients; and 2 down-regulated [hsa-mir-487b, hsa-mir-6777] and 1 up-regulated miRNA [hsa-mir-4525] in Adenoma-Obese-Diabetic patients. The IPA analysis revealed that many of the altered miRNA have known roles in carcinogenic and metabolic syndrome pathways. Conclusion: From the pairwise comparison, diabetes seems to be associated with more alterations of the miRNA profile in the analyzed samples when compared to patients developing colon adenomas on an obesity background. MiRNA-4525 can be used as a potential serum marker in obese patients while miRNA-455, miRNA-219b, and miRNA-8072 can serve as such in diabetic patients. Except for miRNA-455 that was previously described as a promotor of migration and invasion in breast cancer, the other mi-RNAs are novel and their mechanisms of action need further study. Citation Format: Hassan Brim, Mohammad Daremipouran, Gail Nunlee-Bland, Adeyinka Laiyemo, Hassan Ashktorab. Serum analysis of obese and diabetic African American colon adenoma patients reveals novel potential miRNA markers of carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2578.

Metaproteomics of fecal samples of Crohn's disease and Ulcerative Colitis

Crohn's Disease (CD) and Ulcerative Colitis (UC) are chronic inflammatory bowel diseases (IBD) of the gastrointestinal tract. This study used non-invasive LC-MS/MS to find disease specific microbial and human proteins which might be used later for an easier diagnosis.Therefore, 17 healthy controls, 11 CD patients and 14 UC patients but also 13 Irritable Bowel Disease (IBS) patients, 8 Colon Adenoma (CA) patients, and 8 Gastric Carcinoma (GCA) patients were investigated. The proteins were extracted from the fecal samples with liquid phenol in a ball mill. Subsequently, the proteins were digested tryptically to peptides and analyzed by an Orbitrap LC-MS/MS. For protein identification and interpretation of taxonomic and functional results, the MetaProteomeAnalyzer software was used.Cluster analysis and non-parametric test (analysis of similarities) separated healthy controls from patients with CD and UC as well as from patients with GCA. Among others, CD and UC correlated with an increase of neutrophil extracellular traps and immune globulins G (IgG). In addition, a decrease of human IgA and the transcriptional regulatory protein RprY from Bacillus fragilis was found for CD and UC. A specific marker in feces for CD was an increased amount of the human enzyme sucrose-isomaltase. SignificanceCrohn's Disease and Ulcerative Colitis are chronic inflammatory diseases of the gastrointestinal tract, whose diagnosis required comprehensive medical examinations including colonoscopy. The impact of the microbial communities in the gut on the pathogenesis of these diseases is poorly understood. Therefore, this study investigated the impact of gut microbiome on these diseases by a metaproteome approach, revealing several disease specific marker proteins. Overall, this indicated that fecal metaproteomics has the potential to be useful as non-invasive tool for a better and easier diagnosis of both diseases.

Redox, immune and genetic biomarker system for personalized treatments in colorectal cancer.

BACKGROUNDIdentifying biomarkers for the risk of developing degenerative processes linked to aging and colorectal cancer (CRC) onset that could improve clinical strategies.AIMTo determine valid targets and a predictive biomarker’s system of chronicization of inflammation for cancer treatment.METHODSA group of 147 CRC patients was studied. Clinical diagnosis was confirmed histopathologically, and patients were sub-typed using the pathological tumor-node-metastasis classification. Thirteen colon adenoma patients and 219 healthy subjects were also studied. A system biology study on Thioredoxin1/CD30 redox-immune systems (Trx1/CD30), T helper cytokines and polymorphisms of killer immunoglobulin-like receptors, FcγRIIa-131H/R and FcγRIIIa-158V/F was carried out. Enzyme-linked immunosorbent assay was performed to analyze sera. Genetic study was executed by polymerase chain reaction sequence-specific primers and sequence-based typing method. Statistical analysis was performed by using the “Statgraphics software systems”.RESULTSWe found a positive increase between Trx1/RTrx1 levels and sCD30 level and increased age. With respect to the gender relationships, there were distinct differences. Females showed a primary relationship between transforming growth factor beta (TGFβ) with Trx1, whereas males had one with TGFβ and RTrx1. Trx1/CD30 controls the redox immune homeostasis, and an imbalance in the relationship between the Trx1/RTrx1 and sCD30 levels is linked to the onset and progression of tumor. This event happens through different gender-specific cytokine pathways. Our study demonstrated that the serum levels of Trx1/RTrx1, TGFβ/interleukin (IL)6 and TGFβ/IL4 combinations and the sCD30, IFNγ and IL2 combination constitute a predictive gender specific biomarker system. This is relevant for clinical screening to detect the risk of the potential development or progression of a tumor.CONCLUSIONOxidative stress on Trx1/CD30 is a trigger of cancer disease, and the selected oxidation and immune products are a biomarker system for aging and cancer.

Specific clones of Staphylococcus lugdunensis may be associated with colon carcinoma.

Staphylococcus lugdunensis produces a tannase with activity that may be associated with the onset of colon carcinoma. To clarify this feature of colon carcinoma-associated S. lugdunensis, we obtained isolates from healthy subjects and patients with colon adenomas and carcinomas and analyzed their genetic backgrounds. In total, 40 S. lugdunensis isolates from 288 rectal swabs collected between 2002 and 2008 were used. These isolates were classified into four groups according to the diseases of the subjects: healthy (n=13), colon carcinoma (n=13), colon adenoma (n=9), and unknown (n=5). The isolates were also classified by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. In addition, an antimicrobial susceptibility test and detection of resistance genes were performed for all isolates. According to the PFGE analysis, 40 isolates could be classified into five groups. Among the groups, carcinoma and colon adenoma patients were significantly more frequently (40.9%) classified into group D (p<0.05), whereas healthy subjects were more frequently (38.5%) classified into group A. All isolates in group D were typed as ST27, which was clearly different than isolates in the other groups. All isolates were susceptible to the antimicrobial agents tested, including β-lactams, although seven strains produced β-lactamase. Our data suggest that a specific clone of S. lugdunensis might be associated with colon carcinoma and colon adenoma. This clone showed high susceptibility to many antimicrobial agents. Therefore, eradication therapy may lead to a decreased risk of colon carcinoma.

Increased MACC1 levels in tissues and blood identify colon adenoma patients at high risk.

BackgroundColorectal cancer is a preventable disease if caught at early stages. This disease is highly aggressive and has a higher incidence in African Americans. Several biomarkers and mutations of aggressive tumor behavior have been defined such as metastasis-associated in colon cancer 1 (MACC1) that was associated with metastasis in colorectal cancer patients. Here, we aim to assess colon tissue MACC1 protein and circulating MACC1 transcripts in colon preneoplastic and neoplastic African American patients.MethodsPatients’ tissue samples (n = 143) have been arranged on three tissue microarrays for normal (n = 26), adenoma (n = 68) and cancer (n = 49) samples. Immunohistochemistry was used to detect MACC1 expression. Blood samples (n = 93) from normal (n = 45), hyperplastic (n = 15) and tubular adenoma (n = 33) patients were used to assess MACC1 transcripts using qRT-PCR. Distribution of continuous variables was tested between different diagnoses with Kruskal–Wallis test. Categorical variables were tested by Chi square test. We assessed the prognostic ability of IHC staining by calculating area under receiver operating characteristics curve (ROC) for adenoma and cancer separately. Differences between groups in terms of MACC1 transcript levels in plasma were calculated by using non-parametric (exact) Wilcoxon-Mann–Whitney tests. We performed all calculations with SPSS, version 21.ResultsIn patient tissues, there was a statistically significant difference in MACC1 expression in normal vs. adenoma samples (p = 0.004) and normal vs. cancer samples (p < 0.001). There was however no major difference in MACC1 expression between adenoma vs. cancer cases or tubular adenomas vs tubulovillous adenomas. The area under the curve for both normal vs. adenoma and normal vs. cancer cases were 70 and 67 %, respectively. MACC1 expression was not correlated to age, gender or anatomical sample location. In patient plasma, MACC1 transcripts in adenoma patients were significantly higher than in plasma from normal patients (p = 0.014). However, the difference between normal and hyperplastic plasma MACC1 transcripts was not statistically significant.ConclusionMetastasis-associated in colon cancer 1 is expressed at early stages of colorectal oncogenesis within the affected colonic tissue in this patient cohort. The plasma transcripts can be used to stratify African American patients at risk for potential malignant colonic lesions.

Circulating Biomarkers of Gut Barrier Function: Correlates and Nonresponse to Calcium Supplementation among Colon Adenoma Patients.

Gut barrier dysfunction contributes to several gastrointestinal disorders, including colorectal cancer, but factors associated with intestinal hyperpermeability have been minimally studied in humans. We tested the effects of two doses of calcium (1.0 or 2.0 g/d) on circulating biomarkers of gut permeability [anti-flagellin and anti-lipopolysaccharide (LPS) Ig, measured via ELISA] over a 4-month treatment period among colorectal adenoma patients in a randomized, double-blinded, placebo-controlled clinical trial (n = 193), and evaluated the factors associated with baseline levels of these biomarkers. Baseline concentrations of anti-flagellin IgA and anti-LPS IgA were, respectively, statistically significantly proportionately higher by 11.8% and 14.1% among men, 31.3% and 39.8% among those with a body mass index ≥ 35 kg/m(2), and 19.9% and 22.0% among those in the upper relative to the lowest sex-specific tertile of waist circumference. A combined permeability score (the summed optical densities of all four biomarkers) was 24.3% higher among women in the upper tertile of plasma C-reactive protein (Ptrend < 0.01). We found no appreciable effects of supplemental calcium on anti-flagellin or anti-LPS Igs. Our results suggest that (i) men and those with higher adiposity may have greater gut permeability, (ii) gut permeability and systemic inflammation may be directly associated with one another, and (iii) supplemental calcium may not modify circulating levels of gut permeability biomarkers within 4 months. Our findings may improve the understanding of the factors that influence gut permeability to inform development of treatable biomarkers of risk for colorectal cancer and other health outcomes.

Abstract 1532: A Microbiomic analysis in African American with colonic lesions reveals bacterial markers with potential diagnostic value

Abstract Background: Increasing evidence suggests a role of the gut microbiota in colorectal carcinogenesis. However, no specific bacteria have been unequivocally linked to either initiation or progression of colorectal cancer (CRC). Aim: To analyze the taxonomic composition and functional potential of the gut microbiome in African Americans with colorectal lesions with the goal of detecting markers of diagnostic value. Materials &amp; Methods: DNA extracts from 10 stool samples of colon adenoma patients, 10 healthy subjects’ stool samples and from 10 CRC tumors and their matched normal tissues were analyzed for their microbiota composition and genomic content using Illumina MiSeq. Metagenomic Linkage Groups (MLGs) were established and those with high discriminative power between healthy and neoplastic specimens were analyzed for their genetic content. Metagenomic reads from stool samples were mapped against bacterial genes from tissues and vice-versa to identify common markers with discriminative power. Results: The microbiota in both cancer vs. normal tissues and adenoma vs. normal stool samples were different at the 16S rRNA gene level. The metagenomic analysis led to 5 statistically significant MLGs in each set of samples. There was little overlap between the stool-based and tissue-based significant MLGs. Mapping stools reads to annotated tissue genes and vice-versa revealed a panel of 9 bacterial markers with statistically significant discriminative power between normal and adenoma in the stool dataset and visually striking (though non-significant) discriminative power between normal and tumor samples in the tissue dataset. Conclusion: We defined MLGs with discriminative power among cancers vs. normal and adenomas vs. normals and identified 9 bacterial markers that can potentially be used as a panel for non-invasive colorectal cancer screening tests. These findings will need to be validated in a larger population of patients at different stages of the carcinogenic process and from different ethnic/racial backgrounds. Citation Format: Hassan Brim, Sudhir Varma, Adeinko Laiyemo, Zaki Sharif, Edward L. Lee, Hassan Ashktorab. A Microbiomic analysis in African American with colonic lesions reveals bacterial markers with potential diagnostic value. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1532. doi:10.1158/1538-7445.AM2015-1532

Abstract 553: Can MACC1 plasma transcripts in colon adenoma patients be used as an early indicator of metastasis potential

Abstract Background: Several studies have reported the detection of Metastatic Associated Colon Cancer 1 (MACC1) in colorectal cancer (CRC) patients’ tissues and blood. However the expression of this marker in earlier stages has not been investigated. Aim: To determine MACC1 expression in colonic adenoma, CRC, and blood of African Americans (AA). Materials &amp; Methods: Three tissue microarrays of normal (n=32), adenoma (n=74) and CRC (n=46) tissues from AA patients were constructed. Immunohistochemistry (IHC) using an anti-MACC1 antibody was performed. The stained slides were read by two pathologists who were blinded as to the samples diagnosis. Both staining intensity and percentage were established. The IHC results were analyzed in light of the demographic and pathological characteristics of the patients. Plasma samples from normal (n=45), hyperplastic (HPP; n=15) and tubular adenoma (n=33) patients were tested for MACC1 transcripts. A Mann Whitney Rank Sum Test was used to assess the statistical differences in MACC1 transcripts’ detection. Results: The TMA staining revealed MACC1 expression in all three TMAs including the normals. These normals correspond to adjacent tissues to cancer samples which might explain the MACC1 staining. Male gender showed an increase of MACC1 expression in all three TMA separately or combined (p&amp;lt;0.05). The diagnostic ability of MACC1 was good in the adenoma samples when compared to the normal with an AUC=0.65 (95%CI: 0.55-0.74). The cytoplasmic staining percentage in adenomas had the best combination of sensitivity (0.77) and specificity (0.56). This diagnostic value was less significant in cancer samples (AUC=0.51 (95%CI: 0.43-0.58)). MACC1 transcripts were significantly more expressed in colonic lesions samples when compared to normal patients’ plasma (normal vs. (TA+HPP), p=0.014; normal vs. TA: p=0.011). However, MACC1 transcription in normal vs. HPP samples, was not statically significant (P=0.239). Conclusion: Here we demonstrate that MACC1 is expressed very early in the carcinogenic process since it was detected in adenoma tissue from AA. Its correlation with male gender cannot be explained at this time as there are no epidemiological data that support gender associated metastatic phenotype. MACC1 plasma transcripts reveal that this marker is not only detectable in preneoplastic lesions but also released in patients’ circulation. This finding might be capitalized on to determine colonic lesions with potential metastatic characteristics. [U.S. and H.A. contributed equally to this work.] Citation Format: Hassan Brim, Pia Hermann, Mehdi Nouraie, Babak Shokrani, Ed Lee, Tahmineh Haidary, Hassan Ashktorab, Ulrik Stein. Can MACC1 plasma transcripts in colon adenoma patients be used as an early indicator of metastasis potential. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 553. doi:10.1158/1538-7445.AM2014-553

Abstract 4414: Distinct taxonomic, metagenomic and metabolomic profiles from a comprehensive gut flora analysis in healthy and colon adenoma African Americans

Abstract Background: Gut flora has long been suspected to play a role in colorectal cancer (CRC) pathogenesis. Elegant experiments have substantiated such claims with the use of single pathogenic bacteria in germ free colon cancer mouse models. Here we run a comprehensive taxonomic, metagenomic and metabolomics analysis of stool samples from healthy and colon adenoma African American (AA) patients to define further this role. Patients &amp; Methods: DNA extracts from stool samples of 6 healthy and 6 colon adenoma patients were used for the taxonomic and metagenomic analysis. The sequencing was done using a 454 pyrosequencer and the generated data was processed using informatics pipeline for phylogenetic bacterial affiliation and for bacterial functions assignment. For the metabolomics analysis, 10 fecal water extracts from healthy individuals and 10 from colon adenoma patients were analysed for their metabolites’ contents using NMR spectrometry. Results: The analysis of 16S-rDNA sequences revealed the existence of 22 groups of bacteria. A phylogenetic clustering revealed colon adenoma cases clustering together. Most predominant groups in both sets of samples were Clostridia and Bacteroides. No Lactobacilli or Bifidobacteria (good bacteria) were detected. The synergistetes_Dynergistia group -involved in gastrointestinal infections and Firmicutes phylum: Firmicutes group - involved in energy resorption and obesity were 20 and 10 folds more prevalent in adenoma patients, respectively. Bacteria TM7 group that contain active agents in IBD was 5 folds more represented in the control compared to the adenoma group. The metagenomic experiment have led to the generation of about 100,000 reads per sample, 80% of which were successfully annotated. Among the annotated functions, many were differentially present in the colon adenoma compared to healthy individuals. The metabolomics analysis led to a strong clustering of the adenoma samples metabolomes further consolidating the role of bacteria and their metabolites in colon cancer pathology. Conclusion: Our taxonomic, metagenomic and metabolomics analysis have led the presence of clear differential profiles in colon adenoma patients vs. healthy persons. Lack of detection of “good bacteria” (Lactobacilli and Bifidobacteria) in this study defines already a first level of intervention in this high risk CRC population. A comprehensive analysis of all the results is underway to bridge the Taxo, Meta and metabolomics data. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4414. doi:1538-7445.AM2012-4414

Abstract 5380: Prophylactic MUC1/Poly-ICLC vaccine in individuals with the history of advanced colorectal adenoma

Abstract Background MUC1 is aberrantly expressed in a hypoglycosylated form with lack of luminal polarity in variety of human adenocarcinomas including colon cancer. Aberrant MUC1 is also highly expressed in colonic adenomas where it may promote malignant transformation by interacting withβ-catenin known to be an important pathway in colon carcinogenesis. We hypothesized that induction of an immune response against aberrant MUC1 in individuals with a recent history of adenoma may prevent adenoma recurrence and/or their progression to colon cancer. We conducted a clinical study using MUC1 peptide and Poly-ICLC adjuvant vaccine to evaluate the safety and immunogenicity in individuals who are cancer free but at high risk for developing colorectal cancer because of a recent history of advanced adenoma. Method Patients with advanced colorectal adenoma which meets at least one of following criteria: 1) ≥ 1cm in maximal diameter, 2) villous or tubulovillous histology, 3) high-grade dysplasia, were vaccinated with 100μg of 100aa MUC1 peptide (H2N-(GVTSAPDTRPAPGSTAPPAH)5-CONH2) admixed with 500μg of Poly-ICLC (TLR-3 agonist) as adjuvant, on week 0, 2, 10 and one year later. Bloods were collected two weeks after each injection for monitoring of general immunocompetence, development of anti-MUC1 antibody and safety. Results The vaccine was well tolerated without any adverse event grade 2 or higher. Among 36 evaluable patients, anti MUC1 IgG antibody was elicited in 17 patients as measured on week12 (response rate 47.2%). This response rate and the high levels of IgG have never been seen in response to MUC1 vaccines in cancer patients. Antibody titers declined over time but could be boosted to previous or higher levels at 1 year, showing development of immune memory. Vaccine responders were distributed across most HLA-DR and DQ types with similar frequency as in the general population, indicating that the MUC1 peptide could be presented by multiple Class II alleles. Immune competence of colon adenoma patients evaluated by cytokine production of lymphocyte and regulatory T cell frequency was generally equal to healthy individuals, however myeloid derived suppressor cells (MDSCs) were significantly increased in colon adenoma patients. Increase in MDSCs was especially pronounced in non-responders to the vaccine. Conclusion MUC1 poly-ICLC vaccine is highly immunogenic in this prophylactic setting and no significant adverse events have been seen. Vaccine immunogenicity is reduced in individuals with increased numbers of MDSC and this immunosuppressive population might be used as a biomarker to select patients most likely to respond. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5380. doi:1538-7445.AM2012-5380

Oxidative stress and 8-oxoguanine repair are enhanced in colon adenoma and carcinoma patients

Oxidative stress is involved in the pathogenesis of colon cancer. We wanted to elucidate at which stage of the disease this phenomenon occurs. In the examined groups of patients with colorectal cancer (CRC, n = 89), benign adenoma (AD, n = 77) and healthy volunteers (controls, n = 99), we measured: vitamins A, C and E in blood plasma, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanine (8-oxoGua) in leukocytes and urine, leukocyte 8-oxoGua excision activity, mRNA levels of APE1, OGG1, 8-oxo-7,8-dihydrodeoxyguanosine 5'-triphosphate pyrophosphohydrolase (MTH1) and OGG1 polymorphism. The vitamin levels decreased gradually in AD and CRC patients. 8-OxodG increased in leukocytes and urine of CRC and AD patients. 8-OxoGua was higher only in the urine of CRC patients. 8-OxoGua excision was higher in CRC patients than in controls, in spite of higher frequency of the OGG1 Cys326Cys genotype, encoding a glycosylase with decreased activity. mRNA levels of OGG1 and APE1 increased in CRC and AD patients, which could explain increased 8-oxoGua excision rate in CRC patients. MTH1 mRNA was also higher in CRC patients. The results suggest that oxidative stress occurs in CRC and AD individuals. This is accompanied by increased transcription of DNA repair genes, and increased 8-oxoGua excision rate in CRC patients, which is, however, insufficient to counteract the increased DNA damage.

Calcium—cell cycle regulator, differetiator, killer, chemopreventor, and maybe, tumor promoter

Ca2+ and Ca(2+)-binding proteins are involved in running the cell cycle. Ca2+ spikes and signals from integrin-activated focal adhesion complexes and Ca2+ receptors on the cell surface along with cyclic AMP begin the cycle of cyclin-dependent protein kinases (PKs). These transiently expressed PKs stimulate the coordinate expression of DNA-replicating enzymes, activate replication enzymes, inactivate replication suppressors (e.g., retinoblastoma susceptibility protein), activate the replicator complexes at the end of the G1 build-up, and when replication is complete they and a Ca2+ spike trigger mitotic prophase. Another Ca2+ surge at the end of metaphase triggers the destruction of the prophase-stimulating PKs and starts anaphase. Ca2+ finally stimulates cytoplasmic division (cytokinesis). However, Ca2+ does more than this in epithelial cells, such as those lining the colon, and skin keratinocytes. These cells also need Ca2+, integrin signals, and only a small amount (e.g., 0.05-0.1 mM) of external Ca2+ to start DNA replication. Signals from their surface Ca2+ receptors trigger a combination of differentiation and apoptosis ("diffpoptosis") when external Ca2+ concentration reaches their setpoints. The skin's steep, upwardly directed, Ca2+ gradient has a low concentration in the basal layer to allow stem and precursor keratinocytes to proliferate, and higher concentrations in the suprabasal layers to trigger the differentiation-apoptosis ("diffpoptosis") mechanism that converts granular cells into protective, hard-shelled, dead corneocytes. A similar Ca2+ gradient may exist in the colon crypt allowing the stem cell and its amplifying transit or precursor offspring to cycle in the lower parts of the crypt, while stopping proliferation and stimulating terminal differentiation in the upper crypt and flat mucosa. Raising the amount of Ca2+ in fecal water above a critical level reduces proliferation and thus colorectal carcinogenesis in normal rats and some high-risk humans. But during carcinogenesis the Ca2+ sensors malfunction or their signals become ineffective: high Ca2+ does not stop, and may even stimulate, the proliferation of initiated mutants. Therefore, Ca2+ may either not affect, or even promote, the growth of epithelial cells in carcinogen-initiated rat colon and human adenoma patients. Clearly, a much greater understanding of how Ca2+ controls the proliferation and differentiation of epithelial cells and why initiated cells lose their responsiveness to Ca2+ are needed to assess the drawbacks and advantages of using Ca2+ as a chemopreventor.