Role In Development Of Colorectal Cancer Research Articles

Colorectal Cancer Screening and Management in Low- and Middle-Income Countries and High-Income Countries: A Narrative Review.

Colorectal cancer (CRC) remains a leading global health challenge, being a highly prevalent cancer and a major cause of cancer-related deaths worldwide. The incidence of CRC varies significantly between high-income countries (HICs) and low- and middle-income countries (LMICs), with higher rates of incidence but lower mortality in HICs. Factors such as genetic predisposition, lifestyle, and dietary habits play significant roles in CRC development, with the Western diet and limited access to screening contributing to increased incidence. This review highlights disparities in CRC screening, management, and outcomes between HICs and LMICs, with HICs benefiting from advanced screening methods like colonoscopy and sigmoidoscopy, while LMICs face challenges due to limited healthcare infrastructure and resources. Tailored strategies, including low-cost screening options and community-based initiatives, are critical in LMICs to improve early detection and outcomes. Future directions for improving CRC care globally include telemedicine, artificial intelligence, and mobile health technologies to bridge access gaps, as well as personalized medicine to enhance treatment efficacy. Global collaboration and investment in healthcare infrastructure are necessary to reduce CRC-related mortality, particularly in resource-limited settings.

Application of Mendelian randomization analysis in investigating the genetic background of blood biomarkers for colorectal cancer.

Colorectal cancer (CRC), a malignancy affecting the colon and rectum, ranks as the third most common cancer worldwide and the second leading cause of cancer-related deaths. Early detection of CRC is crucial for preventing metastasis, reducing mortality, improving prognosis, and enhancing patients' quality of life. Genetic factors play a significant role in CRC development, accounting for up to 35% of the disease risk. Genome-wide association studies have identified several genetic loci associated with CRC risk. However, these studies often lack direct evidence of causality. While traditional blood biomarkers such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) are widely used for CRC diagnosis and monitoring, their sensitivity and accuracy in early diagnosis are limited. Thus, there is a pressing need to develop new biomarkers that reflect the genetic background of CRC to improve early detection and diagnostic accuracy. In addition, understanding the genetic mechanisms underlying these biomarkers is essential for elucidating CRC pathogenesis and developing precise personalized treatment strategies. Mendelian randomization (MR) analysis, as an emerging epidemiological tool, can accurately assess the causal relationship between genetic variations and diseases by reducing confounding biases in observational studies. MR analysis has been applied in evaluating the causal impact of various blood biomarkers on CRC risk, shedding lights on the potential causal relationships between these biomarkers and CRC pathogenesis in the context of genetic background. In this review, we summarize the applications of MR analysis in studies of blood biomarkers for CRC, aiming to enhance the early diagnosis and personalized treatment of CRC.

Gut commensal Alistipes as a potential pathogenic factor in colorectal cancer

Although previous research has shown that inflammation is associated with development of colorectal cancer (CRC), questions remain about whether inflammatory factor-secreting bacteria play a crucial role in CRC development. The potential role of gut microbiota in secreting inflammatory factors involved in the carcinogenesis of CRC among Chinese patients was explored in this study. 16S rRNA sequencing was utilized to evaluate the distinct microbial characteristics between patients with CRC and colorectal adenoma. The serum levels of TNF-α, IL-6 and IL-10 were measured using Enzyme-linked immunosorbent assay (ELISA), while the expression of LRG1 and TGF-β1 in tissues was evaluated by immunohistochemistry. The correlation between gut microbiota and inflammatory factor signaling was analyzed. Compared with the adenoma group, CRC patients exhibit distinct pathologies. Moreover, elevated levels of CEA, erythrocytes and haemoglobin in the blood of CRC patients were found. In addition, CRC patients have significantly higher levels of TNF-α, IL-6, IL-10, LRG1 and TGF-β1. Spearman correlation analysis revealed that LRG1 was positively related to IL-6 and TNF-α, respectively. The correlation analysis results of TGF-β1 were consistent with the above. The abundance of Blautia and Streptococcus was lower in CRC patients, while the relative abundance of Alistipes, Peptostreptococcus and Porphyromonas was significantly elevated. Moreover, positive correlations between Alistipes and inflammatory factor signaling were also found. Our results suggest that gut commensal Alistipes is a key bacterium with pro-inflammatory properties in the CRC carcinogenesis. TNF-α and IL-6 associated with Alistipes might activate LRG1/TGF-β1 signaling which contributed to the carcinogenesis of CRC.

The Relationship Between Serum and Tissue Levels of IL-13 and TYK2 in Colorectal Cancer Patients

ABSTRACT Introduction Colorectal cancer (CRC) is a third cause of death worldwide. The immune system plays a significant role in the tumor microenvironment and identifying its components involved in cancer development can aid in finding new biomarkers for prognosis, treatment monitoring, and immune-based therapies. Interleukin 13 (IL-13) is a cytokine produced by immune cells that has been implicated in tumor invasion, proliferation, and metastasis. Previous studies have shown that IL-13 causes the phosphorylation of Tyrosine kinase 2 (TYK2), which may contribute to the development and progression of cancer. This study investigated the levels expression of IL-13 and TYK2 in the tissue and serum of CRC patients and explored their possible association with pathological and clinical factors. Methods 105 patients with CRC and 105 healthy individuals were involved in the study. Tissue and blood samples were collected. The quantitative Real-Time PCR (qRT-PCR) technique was used to assess the expression levels of the IL-13 and TYK2 CRC tissue samples in comparison with the adjacent control tissue. Result The expression levels of IL-13 were lower and TYK2 were found to be higher in CRC tissue compared to normal tissue. Additionally, serum levels of IL-13 were decreased in CRC patients while TYK2 levels were elevated. A significant negative correlation was found between the expression levels of IL-13 in both serum and tissue and the cancer stage. Conclusion These results suggest that IL-13 and TYKMay 2 play essential roles in CRC development and progression and may serve as potential biomarkers for early detection and treatment.

Gut Microbiome and colorectal cancer: discovery of bacterial changes with metagenomics application in Turkısh population.

Colorectal cancer (CRC) is the 3rd most common cancer in the world and colonic carcinogenesis is a multifactorial disease that involves environmental and genetic factors. Gut microbiota plays a critical role in the regulation of intestinal homeostasis. Increasing evidence shows that the gut microbiome plays a role in CRC development and may be a biomarker for early diagnosis. This study aimed to determine the clinical prognostic significance of gut microbiota in CRC patients in the Turkish population by metagenomic analysis and to determine the microbial composition in tumor tissue biopsy samples. Tissue biopsies were taken from the participants with sterile forceps during colonoscopy and stored at -80°C. Then, DNA isolation was performed from the tissue samples and the V3-V4 region of the 16S rRNA gene was sequenced on the Illumina MiSeq platform. Quality control of the obtained sequence data was performed. Operational taxonomic units (OTUs) were classified according to the Greengenes database. Alpha diversity (Shannon index) and beta diversity (Bray-Curtis distance) analyses were performed. The most common bacterial species in CRC patients and healthy controls were determined and whether there were statistically significant differences between the groups was tested. A total of 40 individuals, 13 CRC patients and 20 healthy control individuals were included in our metagenomic study. The mean age of the patients was 64.83 and BMI was 25.85. In CRC patients, the level of Bacteroidetes at the phylum taxonomy was significantly increased (p = 0.04), the level of Clostridia at the class taxonomy was increased (p = 0.23), and the level of Enterococcus at the genus taxonomy was significantly increased (p = 0.01). When CRC patients were compared with the control group, significant increases were detected in the species of Gemmiger formicilis (p = 0.15), Prevotella copri (p = 0.02) and Ruminococcus bromii (p = 0.001) at the species taxonomy. Metagenomic analysis of intestinal microbiota composition in CRC patients provides important data for determining the treatment options for these patients. The results of this study suggest that it may be beneficial in terms of early diagnosis, poor prognosis and survival rates in CRC patients. In addition, this metagenomic study is the first study on the colon microbiome associated with CRC mucosa in the Turkish population.

Time to take HPV infection in colorectal cancer patients more seriously.

The association between viral infections and colorectal cancer (CRC) remains an enigma in cancer research. Certain types of Human Papillomaviruses (hr-HPVs), known for their oncogenic properties, have been observed in particular CRC biopsies, further adding to the enigma surrounding this association. This cross-sectional study was conducted on 40 confirmed cases of CRC adenocarcinoma. The presence and genotyping of HPV DNA in colorectal fresh tissue and urine samples was assessed using an HPV DNA hybridization kit. A subset of serum samples from both CRC cases and healthy volunteers was randomly chosen and subjected to western blot to investigate the presence of HPV16 E6/E7 oncoproteins carried by exosomes. It was observed that 26/40 HPV-positive CRC patients demonstrated 7 times more chance to develop colorectal cancer when compared to those 8/40 normal tissue (odds ratio [OR] = 7.4; confidence interval [CI] 95% = 0.483156-0.793718; p < 0.001). Of 26 HPV-positive CRC patients, 14 urine samples were also showed HPV DNA positivity (p = 0.013). High-risk HPV16 was the most prevalent genotype detected in both 24/40 tumor and 12/40 urine samples (p < 0.001). The tumor sample of a male was HPV45, while another male's urine sample was HPV31. A female CRC patient had HPV83 in tumor and HPV56 in urine. Here, was the first detection of HPV83 in a CRC patient. Notably among 20 randomly selected serum exosome samples, one serum sample concurrently tested positive for both HPV16 E6 and E7 oncoproteins, and one sample tested positive for HPV16 E7 oncoprotein. High risk HPV DNA detection in CRC urine samples supports non-invasive screening tools. Detection of HPV16 E6 and E7 oncoproteins in exosomes from serum samples shows potential for non-invasive diagnostics. HPV's potential role in CRC development is also underscored. HPV vaccination should be implemented in low- and middle-income countries to prevent cancer.

NME1 and DCC variants are associated with susceptibility and tumor characteristics in Mexican patients with colorectal cancer

BackgroundColorectal cancer (CRC) ranks third in cancer incidence globally and is the second leading cause of cancer-related mortality. The nucleoside diphosphate kinase 1 (NME1) and netrin 1 receptor (DCC) genes have been associated with resistance against tumorigenesis and tumor metastasis. This study investigates the potential association between NME1 (rs34214448 G > T and rs2302254 C > T) and DCC (rs2229080 G > C and rs714 A > G) variants and susceptibility to colorectal cancer development.MethodsSamples from 232 colorectal cancer patients and 232 healthy blood donors underwent analysis. Variants were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR–RFLP) methodology. Associations were assessed using odds ratios (OR), and the p values were adjusted with Bonferroni test.ResultsIndividuals carrying the G/T and T/T genotypes for the NME1 rs34214448 variant exhibited a higher susceptibility for develop colorectal cancer (OR = 2.68, 95% CI: 1.76–4.09, P = 0.001 and OR = 2.47, 95% CI: 1.37–4.47, P = 0.001, respectively). These genotypes showed significant associations in patients over 50 years (OR = 2.87, 95% CI: 1.81–4.54, P = 0.001 and OR = 2.99, 95% CI: 1.54–5.79, P = 0.001 respectively) and with early Tumor-Nodule-Metastasis (TNM) stage (P = 0.001), and tumor location in the rectum (P = 0.001). Furthermore, the DCC rs2229080 variant revealed that carriers of the G/C genotype had an increased risk for develop colorectal cancer (OR = 2.00, 95% CI: 1.28–3.11, P = 0.002) and were associated with age over 50 years, sex, and advanced TNM stages (P = 0.001).ConclusionsThese findings suggest that the NME1 rs34214448 and DCC rs2229080 variants play a significant role in colorectal cancer development.

Abstract 752: Association of gut bacterial toxins with colorectal neoplasia in Lynch syndrome patients in Puerto Rico

Abstract Lynch syndrome (LS) is an autosomal dominant condition caused by germline mutations in DNA mismatch repair pathway genes that predispose individuals to develop colorectal cancer (CRC) and other malignancies. Not all LS patients develop CRC, and age at diagnosis varies significantly, even among individuals with identical mutations. Although several prospective genetic modifiers have been reported, the contribution of environmental exposures to colorectal carcinogenesis and age of onset is unknown. The gut microbiota composition, influenced by environmental factors, may have a role in CRC development. Dysbiosis, or abnormalities in host-bacteria interactions, can lead to inflammatory bowel disorders and CRC. Certain strains of bacteria, like Escherichia coli and Enterococcus sp., harbor pro-inflammatory/genotoxic genes that promote sustained inflammation in the host- pks, tcpc, gelE, cnf-1, usp, and murB. The association between inflammation and carcinogenesis is well established, yet the contribution of bacteria-induced inflammation and genotoxicity to CRN is not fully understood. This study aims to investigate if changes in the prevalence of the genotoxic/pro-inflammatory bacterial genes are associated with CRN in LS patients. Stool samples were collected from 32 LS subjects and 94 age/gender-matched control subjects without a history of CRC. Qualitative data regarding the six genes in these samples were assessed using RT-PCR with SYBR green. Among LS subjects, 68.8% had two or more of the six genes in their stool samples, whereas controls only had 27.7%. Furthermore, LS subjects had 4.06 times the odds of having ≥2 gut bacterial toxin genes in their stool (95% CI: 1.48-11.12) when compared to controls after adjusting by age. The most prevalent gene in LS patients was murB, detected in 62.5% of the individuals. The presence of gelE and murB genes was significantly higher among LS patients (p-value &amp;lt;0.001 and 0.02, respectively). Interestingly, the usp gene was absent in any LS patients. Additionally, LS subjects had 4.52 times the odds of having the gel-E gene (95% CI: 1.69-12.14) compared to controls after age adjustment. Given the documented evidence about the impact of CRC on the composition of gut microbiota, we performed analysis to assess the prevalence of these genes in LS subjects without a history of CRC, as well as in control subjects. After adjusting by age, LS subjects had higher odds of having ≥2 gut bacterial toxin genes in their stool (OR= 2.94, 95%: CI 0.52-16.50) than controls. This study shows that LS patients have a higher prevalence of the genotoxic/pro-inflammatory bacterial genes. However, further studies are necessary to validate these associations and provide a more comprehensive understanding of the role of gut bacterial genes in colorectal neoplasia among LS patients. Citation Format: Ingrid Montes-Rodriguez, Diego Rodriguez-Santiago, Nicole Marquez-Andino, Gabriela Montalvo-Noguera, Sophia Colon-Serrano, Luis R. Llanos, Olga Diaz-Miranda, Hilmaris Centeno-Girona, Maria Gonzalez-Pons, Marcia Cruz-Correa. Association of gut bacterial toxins with colorectal neoplasia in Lynch syndrome patients in Puerto Rico [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 752.

Abstract 242: Development of organoids-bacteria co-cultures for medium-to-high throughput screening

Abstract HUB patient derived organoids, (HUB-OrganoidsTM or PDOs) are self-organized epithelial cell structures with near-physiological features, extensively used to model aspects of cancer initiation and progression. Microinjection of colibactin-producing pks+ E. coli into the lumen of PDOs resulted in the appearance of two co-occurring mutational signatures identified in a subset of colorectal cancer (CRC) patients, demonstrating that pks+ E. coli plays a causative role in CRC development. The scalability of PDO bacteria microinjection is, however, limited and represent a bottleneck in the screening of preventive therapies for these patients. Here we develop a bacteria-PDO co-culture system (PDO-fragment exposure model), alternative to PDO microinjection, that is compatible with medium-to-high throughput screening methods. We validated the genotoxicity of colibactin-producing bacteria and showed the potential of the PDO fragment exposure model for the screening of drugs targeting colibactin-dependent genotoxicity. Citation Format: Eider Valle-Encinas, Mayke Doorn, Farzin Pourfarzad, Lani San Mateo, Prashanth Gokare, David Pocalyko, Sylvia F. Boj, Carla S. Verissimo. Development of organoids-bacteria co-cultures for medium-to-high throughput screening [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 242.

Competitive endogenous RNA networks: Decoding the role of long non-coding RNAs and circular RNAs in colorectal cancer chemoresistance.

Colorectal cancer (CRC) is recognized as one of the most common gastrointestinal malignancies across the globe. Despite significant progress in designing novel treatments for CRC, there is a pressing need for more effective therapeutic approaches. Unfortunately, many patients undergoing chemotherapy develop drug resistance, posing a significant challenge for cancer treatment. Non-coding RNAs (ncRNAs) have been found to play crucial roles in CRC development and its response to chemotherapy. However, there are still gaps in our understanding of interactions among various ncRNAs, such as long non-coding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs). These ncRNAs can act as either oncogenes or tumour suppressors, affecting numerous biological functions in different cancers including CRC. A class of ncRNA molecules known as competitive endogenous RNAs (ceRNAs) has emerged as a key player in various cellular processes. These molecules form networks through lncRNA/miRNA/mRNA and circRNA/miRNA/mRNA interactions. In CRC, dysregulation of ceRNA networks has been observed across various cellular processes, including proliferation, apoptosis and angiogenesis. These dysregulations are believed to play a significant role in the progression of CRC and, in certain instances, may contribute to the development of chemoresistance. Enriching our knowledge of these dysregulations holds promise for advancing the field of diagnostic and therapeutic modalities for CRC. In this review, we discuss lncRNA- and circRNA-associated ceRNA networks implicated in the emergence and advancement of drug resistance in colorectal carcinogenesis.

Mitochondrial DNA copy number plays opposing roles in T-lymphocyte infiltration of colorectal cancer based on mismatch repair status: new directions for immunotherapy?

Researchers have previously reported that mitochondrial DNA copy number (mtDNA-CN) can play different roles in microsatellite instable/mismatch repair-deficient (MSI/dMMR) and microsatellite stable/mismatch repair-proficient (MSS/pMMR) colorectal cancer (CRC). To support malignancy, dMMR CRC relies on glycolysis, while pMMR CRC favors oxidative phosphorylation. However, it is unclear whether mtDNA-CN changes are related to T cell infiltration in CRC. The mtDNA-CN was detected by qRT-PCR in 532 patients, and the expression of CD3 and CD8 in 485 patients was detected by immunohistochemistry. The correlation between mtDNA-CN and the prognosis of CRC patients was further analyzed, and the correlation between mtDNA-CN and T lymphocyte infiltration was also analyzed. Biopsy specimens from the immune checkpoint inhibitors (ICIs) treatment cohort were obtained to verify the correlation between mtDNA-CN and the efficacy of ICIs. The effects of mtDNA-CN and MMR status on gene expression were analyzed by RNA-seq. Our results show that mtDNA-CN has inverse relationships to CRC prognosis in cases with different MMR statuses, potentially inducing the U-shaped association in CRC. The opposing correlations between mtDNA-CN and T lymphocyte infiltration in cases of dMMR CRC and pMMR CRC further suggest that mtDNA-CN might play an important role in CRC development. More importantly, cases of pMMR CRC with lower mtDNA-CN and of dMMR CRC with higher mtDNA-CN can benefit more dramatically from ICIs. Furthermore, RNA-seq revealed a link between the level of mtDNA-CN and T lymphocyte infiltration in CRC cases with different MMR statuses. Our study found a potential relationship between mtDNA-CN and CRC development that differs by MMR status, potentially providing a rationale for the use of mtDNA-CN as both a predictive biomarker and a therapeutic target for ICIs.

Identifying metabolic features of colorectal cancer liability using Mendelian randomization.

Recognizing the early signs of cancer risk is vital for informing prevention, early detection, and survival. To investigate whether changes in circulating metabolites characterize the early stages of colorectal cancer (CRC) development, we examined the associations between a genetic risk score (GRS) associated with CRC liability (72 single-nucleotide polymorphisms) and 231 circulating metabolites measured by nuclear magnetic resonance spectroscopy in the Avon Longitudinal Study of Parents and Children (N = 6221). Linear regression models were applied to examine the associations between genetic liability to CRC and circulating metabolites measured in the same individuals at age 8 y, 16 y, 18 y, and 25 y. The GRS for CRC was associated with up to 28% of the circulating metabolites at FDR-P < 0.05 across all time points, particularly with higher fatty acids and very-low- and low-density lipoprotein subclass lipids. Two-sample reverse Mendelian randomization (MR) analyses investigating CRC liability (52,775 cases, 45,940 controls) and metabolites measured in a random subset of UK Biobank participants (N = 118,466, median age 58 y) revealed broadly consistent effect estimates with the GRS analysis. In conventional (forward) MR analyses, genetically predicted polyunsaturated fatty acid concentrations were most strongly associated with higher CRC risk. These analyses suggest that higher genetic liability to CRC can cause early alterations in systemic metabolism and suggest that fatty acids may play an important role in CRC development. This work was supported by the Elizabeth Blackwell Institute for Health Research, University of Bristol, the Wellcome Trust, the Medical Research Council, Diabetes UK, the University of Bristol NIHR Biomedical Research Centre, and Cancer Research UK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This work used the computational facilities of the Advanced Computing Research Centre, University of Bristol - http://www.bristol.ac.uk/acrc/.

Whole-transcriptome defines novel glucose metabolic subtypes in colorectal cancer.

Colorectal cancer (CRC) is the most prevalent malignancy of the digestive system. Glucose metabolism plays a crucial role in CRC development. However, the heterogeneity of glucose metabolic patterns in CRC is not well characterized. Here, we classified CRC into specific glucose metabolic subtypes and identified the key regulators. 2228 carbohydrate metabolism-related genes were screened out from the GeneCards database, 202 of them were identified as prognosis genes in the TCGA database. Based on the expression patterns of the 202 genes, three metabolic subtypes were obtained by the non-negative matrix factorization clustering method. The C1 subtype had the worst survival outcome and was characterized with higher immune cell infiltration and more activation in extracellular matrix pathways than the other two subtypes. The C2 subtype was the most prevalent in CRC and was characterized by low immune cell infiltration. The C3 subtype had the smallest number of individuals and had a better prognosis, with higher levels of NRF2 and TP53 pathway expression. Secreted frizzled-related protein 2 (SFRP2) and thrombospondin-2 (THBS2) were confirmed as biomarkers for the C1 subtype. Their expression levels were elevated in high glucose condition, while their knockdown inhibited migration and invasion of HCT 116 cells. The analysis of therapeutic potential found that the C1 subtype was more sensitive to immune and PI3K-Akt pathway inhibitors than the other subtypes. To sum up, this study revealed a novel glucose-related CRC subtype, characterized by SFRP2 and THBS2, with poor prognosis but possible therapeutic benefits from immune and targeted therapies.

Inhibition of TRAP1 Accelerates the DNA Damage Response, Activation of the Heat Shock Response and Metabolic Reprogramming in Colon Cancer Cells.

Colorectal cancer (CRC) is one of the major causes of cancer-related mortality worldwide. The tumor microenvironment plays a significant role in CRC development, progression and metastasis. Oxidative stress in the colon is a major etiological factor impacting tumor progression. Tumor necrosis factor receptor-associated protein 1 (TRAP1) is a mitochondrial member of the heat shock protein 90 (HSP90) family that is involved in modulating apoptosis in colon cancer cells under oxidative stress. We undertook this study to provide mechanistic insight into the role of TRAP1 under oxidative stress in colon cells. We first assessed the The Cancer Genome Atlas (TCGA) CRC gene expression dataset to evaluate the expression of TRAP1 and its association with oxidative stress and disease progression. We then treated colon HCT116 cells with hydrogen peroxide to induce oxidative stress and with the TRAP1 inhibitor gamitrinib-triphenylphosphonium (GTPP) to inhibit TRAP1. We examined the cellular proteomic landscape using liquid chromatography tandem mass spectrometry (LC-MS/MS) in this context compared to controls. We further examined the impact of treatment on DNA damage and cell survival. TRAP1 expression under oxidative stress is associated with the disease outcomes of colorectal cancer. TRAP1 inhibition under oxidative stress induced metabolic reprogramming and heat shock factor 1 (HSF1)-dependent transactivation. In addition, we also observed enhanced induction of DNA damage and cell death in the cells under oxidative stress and TRAP1 inhibition in comparison to single treatments and the nontreatment control. These findings provide new insights into TRAP1-driven metabolic reprogramming in response to oxidative stress.

Alternative Splicing Events and Their Clinical Significance in Colorectal Cancer: Targeted Therapeutic Opportunities.

Colorectal cancer (CRC) ranks as one of the top causes of cancer mortality worldwide and its incidence is on the rise, particularly in low-middle-income countries (LMICs). There are several factors that contribute to the development and progression of CRC. Alternative splicing (AS) was found to be one of the molecular mechanisms underlying the development and progression of CRC. With the advent of genome/transcriptome sequencing and large patient databases, the broad role of aberrant AS in cancer development and progression has become clear. AS affects cancer initiation, proliferation, invasion, and migration. These splicing changes activate oncogenes or deactivate tumor suppressor genes by producing altered amounts of normally functional or new proteins with different, even opposing, functions. Thus, identifying and characterizing CRC-specific alternative splicing events and variants might help in designing new therapeutic splicing disrupter drugs. CRC-specific splicing events can be used as diagnostic and prognostic biomarkers. In this review, alternatively spliced events and their role in CRC development will be discussed. The paper also reviews recent research on alternatively spliced events that might be exploited as prognostic, diagnostic, and targeted therapeutic indicators. Of particular interest is the targeting of protein arginine methyltransferase (PMRT) isoforms for the development of new treatments and diagnostic tools. The potential challenges and limitations in translating these discoveries into clinical practice will also be addressed.

Investigation of Mutated in Colorectal Cancer (MCC) Gene Family Evolution History Indicates a Putative Role in Th17/Treg Differentiation.

The MCC family of genes plays a role in colorectal cancer development through various immunological pathways, including the Th17/Treg axis. We have previously shown that MCC1 but not MCC2 plays a role in Treg differentiation. Our understanding of the genetic divergence patterns and evolutionary history of the MCC family in relation to its function, in general, and the Th17/Treg axis, in particular, remains incomplete. In this investigation, we explored 12 species' genomes to study the phylogenetic origin, structure, and functional specificity of this family. In vertebrates, both MCC1 and MCC2 homologs have been discovered, while invertebrates have a single MCC homolog. We found MCC homologs as early as Cnidarians and Trichoplax, suggesting that the MCC family first appeared 741 million years ago (Ma), whereas MCC divergence into the MCC1 and MCC2 families occurred at 540 Ma. In general, we did not detect significant positive selection regulating MCC evolution. Our investigation, based on MCC1 structural similarity, suggests that they may play a role in the evolutionary changes in Tregs' emergence towards complexity, including the ability to utilize calcium for differentiation through the use of the EFH calcium-binding domain. We also found that the motif NPSTGE was highly conserved in MCC1, but not in MCC2. The NPSTGE motif binds KEAP1 with high affinity, suggesting an Nrf2-mediated function for MCC1. In the case of MCC2, we found that the "modifier of rudimentary" motif is highly conserved. This motif contributes to the regulation of alternative splicing. Overall, our study sheds light on how the evolution of the MCC family is connected to its function in regulating the Th17/Treg axis.

Colorectal polyps increase the glycolytic activity.

In colorectal cancer (CRC) energy metabolism research, the precancerous stage of polyp has remained rather unexplored. By now, it has been shown that CRC has not fully obtained the glycolytic phenotype proposed by O. Warburg and rather depends on mitochondrial respiration. However, the pattern of metabolic adaptations during tumorigenesis is still unknown. Understanding the interplay between genetic and metabolic changes that initiate tumor development could provide biomarkers for diagnosing cancer early and targets for new cancer therapeutics. We used human CRC and polyp tissue material and performed high-resolution respirometry and qRT-PCR to detect changes on molecular and functional level with the goal of generally describing metabolic reprogramming during CRC development. Colon polyps were found to have a more glycolytic bioenergetic phenotype than tumors and normal tissues. This was supported by a greater GLUT1, HK, LDHA, and MCT expression. Despite the increased glycolytic activity, cells in polyps were still able to maintain a highly functional OXPHOS system. The mechanisms of OXPHOS regulation and the preferred substrates are currently unclear and would require further investigation. During polyp formation, intracellular energy transfer pathways become rearranged mainly by increasing the expression of mitochondrial adenylate kinase (AK) and creatine kinase (CK) isoforms. Decreased glycolysis and maintenance of OXPHOS activity, together with the downregulation of the CK system and the most common AK isoforms (AK1 and AK2), seem to play a relevant role in CRC development.

The role of G1/S phase cyclins in colorectal cancer; a review article

Colorectal cancer is a highly prevalent cancer with a high mortality rate. Although the colorectal carcinogenesis mechanism is not fully understood yet, it has been proven that most cancers result from the accumulation of genetic mutations, mostly in the genes responsible for cell cycle regulation, leading to uncontrolled and excessive cell growth. Hence, cyclins may have a significant role in cancer development and progression. Although many studies have been carried out on the expression of these cyclin proteins to indicate their role in colorectal cancer development and their correlation with patient outcome, the currently available data is quite controversial; thus, no certain conclusions can be made. This review article summarizes current knowledge regarding the role of G1/S cyclins, such as cyclin D, E, and A, in colorectal cancer and discusses their potential as prognostic biomarkers and therapeutic targets. Hence, it may provide the groundwork for future research.

Tumor-suppressive role of the musculoaponeurotic fibrosarcoma gene in colorectal cancer

Somatic cell reprogramming using the microRNAs miR-200c, miR-302s, and miR-369s leads to increased expression of cyclin-dependent kinase inhibitors in human colorectal cancer (CRC) cells and suppressed tumor growth. Here, we investigated whether these microRNAs inhibit colorectal tumorigenesis in CPC;Apc mice, which are prone to colon and rectal polyps. Repeated administration of microRNAs inhibited polyp formation. Microarray analysis indicated that c-MAF, which reportedly shows oncogene-like behavior in multiple myeloma and Tcell lymphoma, decreased in tumor samples but increased in microRNA-treated normal mucosa. Immunohistochemistry identified downregulation of c-MAF as an early tumorigenesis event in CRC, with low c-MAF expression associated with poor prognosis. Of note, c-MAF expression and p53 protein levels were inversely correlated in CRC samples. c-MAF knockout led to enhanced tumor formation in azoxymethane/dextran sodium sulfate-treated mice, with activation of cancer-promoting genes. c-MAF may play a tumor-suppressive role in CRC development.

Genomic profiles of Indonesian colorectal cancer patients.

Background: Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide and genetic mutation plays a vital role in CRC development. A previous study has suggested that genetic alterations among Indonesian patients with CRC might differ from those known in developed countries. This study aimed to describe the genomic profiles of Indonesian patients with CRC. Methods: A total of 13 patients were recruited for this study from May to July 2019. Tissue samples were collected, and genomic DNA was extracted from the samples. AmpliSeq for Illumina Cancer HotSpot Panel v2 Next-generation sequencing was used for DNA sequencing and a genome analysis toolkit was used for local realignment around the discovered variants. Results: A total of 45 genes comprising 391 single nucleotide variants (SNVs) with a depth >10 were observed. The genes with the most variants were STK11, SMAD4, EGFR, and ERBB4 and the genes with the most non-synonymous variants were SMAD4, TP53, FGFR3, CDKN2A, and STK11. Genes and SNVs in at least 90% of all samples consisted of 43 genes comprising 286 variants. Genes with the most non-synonymous SNVs were EGFR, SMO, FGFR3, TP53, STK11, CDKN2A. Genes related to the chromosomal instability pathway, such as TP53, SMAD4, KRAS, and APC, are also found in the analysis. Conclusions: Our findings showed that all patients with CRC in this study had genetic mutations in the chromosomal instability pathway. Analysis of genetic mutation of Indonesian patients with CRC might be crucial for advanced targeted therapy and for better clinical outcomes.