Driver mutations of the adenoma-carcinoma sequence govern the intestinal epithelial global translational capacity

Research Advances of Lipid Nanoparticles in the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a common type of gastrointestinal tract (GIT) cancer and poses an enormous threat to human health. Current strategies for metastatic colorectal cancer (mCRC) therapy primarily focus on chemotherapy, targeted therapy, immunotherapy, and radiotherapy; however, their adverse reactions and drug resistance limit their clinical application. Advances in nanotechnology have rendered lipid nanoparticles (LNPs) a promising nanomaterial-based drug delivery system for CRC therapy. LNPs can adapt to the biological characteristics of CRC by modifying their formulation, enabling the selective delivery of drugs to cancer tissues. They overcome the limitations of traditional therapies, such as poor water solubility, nonspecific biodistribution, and limited bioavailability. Herein, we review the composition and targeting strategies of LNPs for CRC therapy. Subsequently, the applications of these nanoparticles in CRC treatment including drug delivery, thermal therapy, and nucleic acid-based gene therapy are summarized with examples provided. The last section provides a glimpse into the advantages, current limitations, and prospects of LNPs in the treatment of CRC.

National Trends in the Incidence of Sporadic Malignant Colorectal Polyps in Young Patients (20-49 Years): An 18-Year SEER Database Analysis

Background and Objectives: Conflicting guidelines exist for initiating average-risk colorectal cancer screening at the age of 45 years. The United States Preventive Services Task Force (USPSTF) changed its guidelines in 2021 to recommend initiating screening at 45 years due to an increasing incidence of young-onset colorectal cancer. However, the American College of Physicians (ACP) recently recommended not screening average-risk individuals between 45 and 49 years old. We aim to study the national trends in the incidence of sporadic malignant polyps (SMP) in patients from 20 to 49 years old. Materials and Methods: We analyzed the Surveillance, Epidemiology, and End Results database (2000-2017) on patients aged 20-49 years who underwent diagnostic colonoscopy with at least a single malignant sporadic colorectal polyp. Results: Of the 10,742 patients diagnosed with SMP, 42.9% were female. The mean age of incidence was 43.07 years (42.91-43.23, 95% CI). Approximately 50% of malignant polyps were diagnosed between 45 and 49 years of age, followed by 25-30% between 40 and 45. There was an upward trend in malignant polyps, with a decreased incidence of malignant villous adenomas and a rise in malignant adenomas and tubulovillous adenomas. Conclusions: Our findings suggest that almost half of the SMPs under 50 years occurred in individuals under age 45, younger than the current screening threshold recommended by the ACP. There has been an upward trend in malignant polyps in the last two decades. This reflects changes in tumor biology, and necessitates further research and support in the USPSTF guidelines to start screening at the age of 45 years.

ER stress and the unfolded protein response in gastrointestinal stem cells and carcinogenesis

Endoplasmic reticulum (ER) stress and the adaptive response that follows, termed the unfolded protein response (UPR), are crucial molecular mechanisms to maintain cellular integrity by safeguarding proper protein synthesis. Next to being important in protein homeostasis, the UPR is intricate in cell fate decisions such as proliferation, differentiation, and stemness. In the intestine, stem cells are critical in governing epithelial homeostasis and they are the cell of origin of gastrointestinal malignancies. In this review, we will discuss the role of ER stress and the UPR in the gastrointestinal tract, focusing on stem cells and carcinogenesis. Insights in mechanisms that connect ER stress and UPR with stemness and carcinogenesis may broaden our understanding in the development of cancer throughout the gastrointestinal tract and how we can exploit these mechanisms to target these malignancies.

Exploring the role of sporadic BRAF and KRAS mutations during colorectal cancer pathogenesis: A spotlight on the contribution of the endosome-lysosome system

The highly heterogenous nature of colorectal cancer can significantly hinder its early and accurate diagnosis, eventually contributing to high mortality rates. The adenoma-carcinoma sequence and serrated polyp-carcinoma sequence are the two most common sequences in sporadic colorectal cancer. Genetic alterations in adenomatous polyposis coli (APC), v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) and tumour protein 53 (TP53) genes are critical in adenoma-carcinoma sequence, whereas v-Raf murine sarcoma viral oncogene homolog B (BRAF) and MutL Homolog1 (MLH1) are driving oncogenes in the serrated polyp-carcinoma sequence. Sporadic mutations in these genes contribute differently to colorectal cancer pathogenesis by introducing distinct alterations in several signalling pathways that rely on the endosome-lysosome system. Unsurprisingly, the endosome-lysosome system plays a pivotal role in the hallmarks of cancer and contributes to specialised colon function. Thus, the endosome-lysosome system might be distinctively influenced by different mutations and these alterations may contribute to the heterogenous nature of sporadic colorectal cancer. This review highlights potential connections between major sporadic colorectal cancer mutations and the diverse pathogenic mechanisms driven by the endosome-lysosome system in colorectal carcinogenesis.

Macrophage Inflammatory Proteins (MIPs) Contribute to Malignant Potential of Colorectal Polyps and Modulate Likelihood of Cancerization Associated with Standard Risk Factors

Better understanding of molecular changes leading to neoplastic transformation is prerequisite to optimize risk assessment and chemopreventive and surveillance strategies. Data on macrophage inflammatory proteins (MIPs) in colorectal carcinogenesis are scanty and their clinical relevance remains unknown. Therefore, transcript and protein expression of CCL3, CCL4, CXCL2, and CCL19 were determined in 173 and 62 patients, respectively, using RT-qPCR and immunohistochemistry with reference to polyps' characteristics. The likelihood of malignancy was modeled using probit regression. With the increasing malignancy potential of hyperplastic-tubular-tubulo-villous-villous polyps, the expression of CCL3, CCL4, and CCL19 in lesions decreased. CCL19 expression decreased also in normal mucosa while that of CXCL2 increased. Likewise, lesion CCL3 and lesion and normal mucosa CCL19 decreased and normal CXCL2 increased along the hyperplasia-low-high dysplasia grade. The bigger the lesion, the lower CCL3 and higher CXCL2 in normal mucosa. Singular polyps had higher CCL3, CCL4, and CCL19 levels in normal mucosa. CCL3, CCL4 and CXCL2 modulated the likelihood of malignancy associated with traditional risk factors. There was no correlation between the protein and mRNA expression of CCL3 and CCL19. In summary, the polyp-adjacent mucosa contributes to gaining potential for malignancy by polyps. MIPs may help in specifying cancerization probability estimated based on standard risk factors.

Centrosomal Protein 55 (CEP55) Drives Immune Exclusion and Resistance to Immune Checkpoint Inhibitors in Colorectal Cancer

Colorectal cancer (CRC) currently ranks as the third most common cancer in the United States, and its incidence is on the rise, especially among younger individuals. Despite the remarkable success of immune checkpoint inhibitors (ICIs) in various cancers, most CRC patients fail to respond due to intrinsic resistance mechanisms. While microsatellite instability-high phenotypes serve as a reliable positive predictive biomarker for ICI treatment, the majority of CRC patients with microsatellite-stable (MSS) tumors remain ineligible for this therapeutic approach. In this study, we investigated the role of centrosomal protein 55 (CEP55) in shaping the tumor immune microenvironment in CRC. CEP55 is overexpressed in multiple cancer types and was shown to promote tumorigenesis by upregulating the PI3K/AKT pathway. Our data revealed that elevated CEP55 expression in CRC was associated with reduced T cell infiltration, contributing to immune exclusion. As CRC tumors progressed, CEP55 expression increased alongside sequential mutations in crucial driver genes (APC, KRAS, TP53, and SMAD4), indicating its involvement in tumor progression. CEP55 knockout significantly impaired tumor growth in vitro and in vivo, suggesting that CEP55 plays a crucial role in tumorigenesis. Furthermore, the CEP55 knockout increased CD8+ T cell infiltration and granzyme B production, indicating improved anti-tumor immunity. Additionally, we observed reduced regulatory T cell infiltration in CEP55 knockout tumors, suggesting diminished immune suppression. Most significantly, CEP55 knockout tumors demonstrated enhanced responsiveness to immune checkpoint inhibition in a clinically relevant orthotopic CRC model. Treatment with anti-PD1 significantly reduced tumor growth in CEP55 knockout tumors compared to control tumors, suggesting that inhibiting CEP55 could improve the efficacy of ICIs. Collectively, our study underscores the crucial role of CEP55 in driving immune exclusion and resistance to ICIs in CRC. Targeting CEP55 emerges as a promising therapeutic strategy to sensitize CRC to immune checkpoint inhibition, thereby improving survival outcomes for CRC patients.

Expanded Alternatives of CRISPR-Cas9 Applications in Immunotherapy of Colorectal Cancer

Immunotherapy for colorectal cancer (CRC) is limited to patients with advanced disease who have already undergone first-line chemotherapy and whose tumors exhibit microsatellite instability. Novel technical strategies are required to enhance therapeutic options and achieve a more robust immunological response. Therefore, exploring gene analysis and manipulation at the molecular level can further accelerate the development of advanced technologies to address these challenges. The emergence of advanced genome editing technology, particularly of clustered, regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein (Cas) 9, holds promise in expanding the boundaries of cancer immunotherapy. In this manuscript, we provide a comprehensive review of the applications and perspectives of CRISPR technology in improving the design, generation, and efficiency of current immunotherapies, focusing on solid tumors such as colorectal cancer, where these approaches have not been as successful as in hematological conditions.

Machine learning-based meta-analysis of colorectal cancer and inflammatory bowel disease

Colorectal cancer (CRC) is a major global health concern, resulting in numerous cancer-related deaths. CRC detection, treatment, and prevention can be improved by identifying genes and biomarkers. Despite extensive research, the underlying mechanisms of CRC remain elusive, and previously identified biomarkers have not yielded satisfactory insights. This shortfall may be attributed to the predominance of univariate analysis methods, which overlook potential combinations of variants and genes contributing to disease development. Here, we address this knowledge gap by presenting a novel multivariate machine-learning strategy to pinpoint genes associated with CRC. Additionally, we applied our analysis pipeline to Inflammatory Bowel Disease (IBD), as IBD patients face substantial CRC risk. The importance of the identified genes was substantiated by rigorous validation across numerous independent datasets. Several of the discovered genes have been previously linked to CRC, while others represent novel findings warranting further investigation. A Python implementation of our pipeline can be accessed publicly at https://github.com/AriaSar/CRCIBD-ML.

Colorectal cancer cell exosome and cytoplasmic membrane for homotypic delivery of therapeutic molecules

Colorectal cancer (CRC) is one of the most common causes of death in the world. The multi-drug resistance, especially in metastatic colorectal cancer, drives the development of new strategies that secure a positive outcome and reduce undesirable side effects. Nanotechnology has made an impact in addressing some pharmacokinetic and safety issues related to administration of free therapeutic agents. However, demands of managing complex biointerfacing require equally complex methods for introducing stimuli-responsive or targeting elements. In order to procure a more efficient solution to the overcoming of biological barriers, the physiological functions of cancer cell plasma and exosomal membranes provided the source of highly functionalized coatings. Biomimetic nanovehicles based on colorectal cancer (CRC) membranes imparted enhanced biological compatibility, immune escape and protection to diverse classes of therapeutic molecules. When loaded with therapeutic load or used as a coating for other therapeutic nanovehicles, they provide highly efficient and selective cell targeting and uptake. This review presents a detailed overview of the recent application of homotypic biomimetic nanovehicles in the management of CRC. We also address some of the current possibilities and challenges associated with the CRC membrane biomimetics.

Grp78 is required for intestinal Kras-dependent glycolysis proliferation and adenomagenesis

In development of colorectal cancer, mutations in APC are often followed by mutations in oncogene KRAS The latter changes cellular metabolism and is associated with the Warburg phenomenon. Glucose-regulated protein 78 (Grp78) is an important regulator of the protein-folding machinery, involved in processing and localization of transmembrane proteins. We hypothesize that targeting Grp78 in Apc and Kras (AK)-mutant intestines interferes with the metabolic phenotype imposed by Kras mutations. In mice with intestinal epithelial mutations in Apc, Kras G12D and heterozygosity for Grp78 (AK-Grp78 HET ) adenoma number and size is decreased compared with AK-Grp78 WT mice. Organoids from AK-Grp78 WT mice exhibited a glycolysis metabolism which was completely rescued by Grp78 heterozygosity. Expression and correct localization of glucose transporter GLUT1 was diminished in AK-Grp78 HET cells. GLUT1 inhibition restrained the increased growth observed in AK-mutant organoids, whereas AK-Grp78 HET organoids were unaffected. We identify Grp78 as a critical factor in Kras-mutated adenomagenesis. This can be attributed to a critical role for Grp78 in GLUT1 expression and localization, targeting glycolysis and the Warburg effect.

Unlocking the Potential of the CA2, CA7, and ITM2C Gene Signatures for the Early Detection of Colorectal Cancer: A Comprehensive Analysis of RNA-Seq Data by Utilizing Machine Learning Algorithms

Colorectal cancer affects the colon or rectum and is a common global health issue, with 1.1 million new cases occurring yearly. The study aimed to identify gene signatures for the early detection of CRC using machine learning (ML) algorithms utilizing gene expression data. The TCGA-CRC and GSE50760 datasets were pre-processed and subjected to feature selection using the LASSO method in combination with five ML algorithms: Adaboost, Random Forest (RF), Logistic Regression (LR), Gaussian Naive Bayes (GNB), and Support Vector Machine (SVM). The important features were further analyzed for gene expression, correlation, and survival analyses. Validation of the external dataset GSE142279 was also performed. The RF model had the best classification accuracy for both datasets. A feature selection process resulted in the identification of 12 candidate genes, which were subsequently reduced to 3 (CA2, CA7, and ITM2C) through gene expression and correlation analyses. These three genes achieved 100% accuracy in an external dataset. The AUC values for these genes were 99.24%, 100%, and 99.5%, respectively. The survival analysis showed a significant logrank p-value of 0.044 for the final gene signatures. The analysis of tumor immunocyte infiltration showed a weak correlation with the expression of the gene signatures. CA2, CA7, and ITM2C can serve as gene signatures for the early detection of CRC and may provide valuable information for prognostic and therapeutic decision making. Further research is needed to fully understand the potential of these genes in the context of CRC.

Difficult diagnosis in the clinical evaluation of a patient with squamous cell carcinoma of the sigmoid colon: a case report

BACKGROUND

Squamous cell carcinoma (SCC) of the sigmoid colon is an exceedingly rare subtype of colorectal cancer (CRC) associated with chronic inflammatory conditions. Due to its variable clinical presentation ranging from subclinical to fully symptomatic and limited available information, it poses a diagnostic challenge. We aim to provide a review of the current literature and raise awareness about the importance of a thorough clinical analysis for an early diagnosis.

CASE PRESENTATION

We describe the case of a 59-year-old Peruvian woman with a medical history of diverticular disease and irritable bowel syndrome. The patient presented with nonspecific symptoms such as abdominal discomfort, constipation, and bloating. Diagnostic tests and biopsy revealed a rare case of squamous cell carcinoma of the sigmoid colon. The patient underwent surgical resection and adjuvant chemotherapy.

CONCLUSION

Despite the rarity of this type of cancer in the colon, the patient's clinical course highlights the importance of considering it as a potential diagnosis in patients with nonspecific symptoms and a history of gastrointestinal disorders. Surgical treatment followed by radiotherapy is the preferred management. Factors such as lack of postoperative complications and the stage of the neoplasia can augur a positive.

PROGNOSIS

A prompt diagnosis is crucial, as detecting a neoplasia in its early stages can make surgery more effective.

Genomic landscape of locally advanced rectal adenocarcinoma: Comparison between before and after neoadjuvant chemoradiation and effects of genetic biomarkers on clinical outcomes and tumor response

PURPOSE

To explore genomic biomarkers in rectal cancer by performing whole-exome sequencing.

MATERIALS AND METHODS

Pre-chemoradiation (CRT) biopsy and post-CRT surgical specimens were obtained from 27 patients undergoing neoadjuvant CRT followed by definitive resection. Exomes were sequenced to a mean coverage of 30×. Somatic single-nucleotide variants (SNVs) and insertions/deletions (indels) were identified. Tumor mutational burden was defined as the number of SNVs or indels. Mutational signatures were extracted and fitted to COSMIC reference signatures. Tumor heterogeneity was quantified with a mutant-allele tumor heterogeneity (MATH) score. Genetic biomarkers and frequently occurred copy number alterations (CNAs) were compared between pre- and post-CRT specimens. Their associations with tumor regression grade (TRG) and clinical outcomes were explored.

RESULTS

Top five mutated genes were APC, TP53, NF1, KRAS, and NOTCH1 for pre-CRT samples and APC, TP53, NF1, CREBBP, and ATM for post-CRT samples. Several gene mutations including RUNX1, EGFR, and TP53 in pre-CRT samples showed significant association with clinical outcomes, but not with TRG. However, no such association was found in post-CRT samples. Discordance of driver mutation status was found between pre- and post-CRT samples. In tumor mutational burden analysis, higher number of SNVs or indels was associated with worse treatment outcomes. Six single-base substitution (SBS) signatures identified were SBS1, SBS30, SBS29, SBS49, SBS3, and SBS44. The MATH score decreased after CRT on paired analysis. Less than half of CNAs frequent in post-CRT samples were present in pre-CRT samples.

CONCLUSION

Pre- and post-CRT samples showed different genomic landscape. Potential genetic biomarkers of pre-CRT samples found in the current analysis call for external validation.

Quassinoid analogs exert potent antitumor activity via reversible protein biosynthesis inhibition in human colorectal cancer

Cellular protein synthesis is accelerated in human colorectal cancer (CRC), and high expression of protein synthesis regulators in CRC patients is associated with poor prognosis. Thus, inhibition of protein synthesis may be an effective therapeutic strategy for CRC. We previously demonstrated that the quassinoid bruceantinol (BOL) had antitumor activity against CRC. Herein, potent tumor growth suppression (>80%) and STAT3 inhibition was observed in two different mouse models following BOL administration. Loss of body and spleen weight was observed but was eliminated upon nanoparticle encapsulation while maintaining strong antitumor activity. STAT3 siRNA knockdown exhibited modest suppression of cell proliferation. Surprisingly, STAT3 inhibition using a PROTAC degrader (SD-36) had little effect on cancer cell proliferation suggesting the possibility of additional mechanism(s) of action for quassinoids. BOL-resistant (BR) cell lines, HCT116BR and HCA7BR, were equally sensitive to standard CRC therapeutic agents and known STAT3 inhibitors but resistant to homoharringtonine (HHT), a known protein synthesis inhibitor. The ability of quassinoids to inhibit protein synthesis was dependent on the structure of the C15 sidechain. Of note, BOL did not inhibit protein synthesis in normal human colon epithelial cells whereas HHT and napabucasin remained effective in these normal cells. Novel quassinoids were designed, synthesized, and evaluated in pre-clinical CRC models. Treatment with the most potent analog, 5c, resulted in significant inhibition of cell proliferation and protein synthesis at nanomolar concentrations. These quassinoid analogs may represent a novel class of protein synthesis inhibitors for the treatment of human CRC.

Colorectal Cancer-The "Parent" of Low Bowel Obstruction

Introduction: Despite the improvement of early diagnosis methods for multiple pathological entities belonging to the digestive tract, bowel obstruction determined by multiple etiologies represents an important percentage of surgical emergencies. General data: Although sometimes obstructive episodes are possible in the early stages of colorectal cancer, the most commonly installed intestinal obstruction has the significance of an advanced evolutionary stage of neoplastic disease. Development of Obstructive Mechanism: The spontaneous evolution of colorectal cancer is always burdened by complications. The most common complication is low bowel obstruction, found in approximately 20% of the cases of colorectal cancer, and it can occur either relatively abruptly, or is preceded by initially discrete premonitory symptoms, non-specific (until advanced evolutionary stages) and generally neglected or incorrectly interpreted. Success in the complex treatment of a low neoplastic obstruction is conditioned by a complete diagnosis, adequate pre-operative preparation, a surgical act adapted to the case (in one, two or three successive stages), and dynamic postoperative care. The moment of surgery should be chosen with great care and is the result of the experience of the anesthetic-surgical team. The operative act must be adapted to the case and has as its main objective the resolution of intestinal obstruction and only in a secondary way the resolution of the generating disease. Conclusions: The therapeutic measures adopted (medical-surgical) must have a dynamic character in accordance with the particular situation of the patient. Except for certain or probably benign etiologies, the possibility of colorectal neoplasia should always be considered, in low obstructions, regardless of the patient's age.

Krüppel-like Factors 4 and 5 in Colorectal Tumorigenesis

Krüppel-like factors (KLFs) are transcription factors regulating various biological processes such as proliferation, differentiation, migration, invasion, and homeostasis. Importantly, they participate in disease development and progression. KLFs are expressed in multiple tissues, and their role is tissue- and context-dependent. KLF4 and KLF5 are two fascinating members of this family that regulate crucial stages of cellular identity from embryogenesis through differentiation and, finally, during tumorigenesis. They maintain homeostasis of various tissues and regulate inflammation, response to injury, regeneration, and development and progression of multiple cancers such as colorectal, breast, ovarian, pancreatic, lung, and prostate, to name a few. Recent studies broaden our understanding of their function and demonstrate their opposing roles in regulating gene expression, cellular function, and tumorigenesis. This review will focus on the roles KLF4 and KLF5 play in colorectal cancer. Understanding the context-dependent functions of KLF4 and KLF5 and the mechanisms through which they exert their effects will be extremely helpful in developing targeted cancer therapy.

The Role of WNT Pathway Mutations in Cancer Development and an Overview of Therapeutic Options

It is well established that mutations in the canonical WNT-signalling pathway play a major role in various cancers. Critical to developing new therapeutic strategies is understanding which cancers are driven by WNT pathway activation and at what level these mutations occur within the pathway. Some cancers harbour mutations in genes whose protein products operate at the receptor level of the WNT pathway. For instance, tumours with RNF43 or RSPO mutations, still require exogenous WNT ligands to drive WNT signalling (ligand-dependent mutations). Conversely, mutations within the cytoplasmic segment of the Wnt pathway, such as in APC and CTNNB1, lead to constitutive WNT pathway activation even in the absence of WNT ligands (ligand-independent). Here, we review the predominant driving mutations found in cancer that lead to WNT pathway activation, as well as explore some of the therapeutic interventions currently available against tumours harbouring either ligand-dependent or ligand-independent mutations. Finally, we discuss a potentially new therapeutic avenue by targeting the translational apparatus downstream from WNT signalling.

Identification and clinical validation of key genes as the potential biomarkers in colorectal adenoma

BACKGROUND

Colorectal cancer (CRC), ranking third in cancer prevalence and second in mortality worldwide, is mainly derived from colorectal adenoma (CRA). CRA is a common benign disease in the intestine with rapidly increasing incidence and malignant potential. Therefore, this study aimed to recognize significant biomarkers and original pathogenesis in CRA.

METHODS

Transcriptome data of GSE8671, GSE37364, and GSE15960 were downloaded from the Gene Expression Omnibus (GEO) datasets, and differentially expressed genes (DEGs) were screened. Functional pathways enrichment, protein-protein interaction (PPI) network, stem-correlation analysis, CIBERSORT, risk score and survival analyses were performed. RT-qPCR and immunohistochemical staining were applied to verify our results.  RESULTS: Screening for significant DEGs in each dataset, we identified 230 robust DEGs, including 127 upregulated and 103 downregulated genes. Functional pathways enrichment showed that these DEGs were distinctly enriched in various tumor-associated pathways, such as growth factor activity, extracellular structure organization, neutrophil activation, and inflammatory response. We filtered out two hub genes via STRING and Modules analysis, including CA2 and HSD11B2. Stem-correlation analysis displayed that hub genes were negatively associated with stem-related genes (Olfm4, CD44, CCND1 and MYC). The CIBERSORT algorithm indicated that Macrophage2, activated mast cells, and Neutrophils promoted CRA progression through inflammation. Survival analysis showed that CA2 and HSD11B2 were positively associated with survival outcomes in CRC.

CONCLUSION

Our study has successfully identified the critical role of two core genes in the development and oncogenesis of CRA, which provides novel insight into the underlying pathogenesis, potential biomarkers and therapeutic targets.

SMAD4 Loss Induces c-MYC-Mediated NLE1 Upregulation to Support Protein Biosynthesis, Colorectal Cancer Growth, and Metastasis

Growth and metastasis of colorectal cancer is closely connected to the biosynthetic capacity of tumor cells, and colorectal cancer stem cells that reside at the top of the intratumoral hierarchy are especially dependent on this feature. By performing disease modeling on patient-derived tumor organoids, we found that elevated expression of the ribosome biogenesis factor NLE1 occurs upon SMAD4 loss in TGFβ1-exposed colorectal cancer organoids. TGFβ signaling-mediated downregulation of NLE1 was prevented by ectopic expression of c-MYC, which occupied an E-box-containing region within the NLE1 promoter. Elevated levels of NLE1 were found in colorectal cancer cohorts compared with normal tissues and in colorectal cancer subtypes characterized by Wnt/MYC and intestinal stem cell gene expression. In colorectal cancer cells and organoids, NLE1 was limiting for de novo protein biosynthesis. Upon NLE1 ablation, colorectal cancer cell lines activated p38/MAPK signaling, accumulated p62- and LC3-positive structures indicative of impaired autophagy, and displayed more reactive oxygen species. Phenotypically, knockout of NLE1 inhibit.ed proliferation, migration and invasion, clonogenicity, and anchorage-independent growth. NLE1 loss also increased the fraction of apoptotic tumor cells, and deletion of TP53 further sensitized NLE1-deficient colorectal cancer cells to apoptosis. In an endoscopy-guided orthotopic mouse transplantation model, ablation of NLE1 impaired tumor growth in the colon and reduced primary tumor-derived liver metastasis. In patients with colorectal cancer, NLE1 mRNA levels predicted overall and relapse-free survival. Taken together, these data reveal a critical role of NLE1 in colorectal cancer growth and progression and suggest that NLE1 represents a potential therapeutic target in colorectal cancer patients.

SIGNIFICANCE

NLE1 limits de novo protein biosynthesis and the tumorigenic potential of advanced colorectal cancer cells, suggesting NLE1 could be targeted to improve the treatment of metastatic colorectal cancer.

Intestinal Apc-inactivation induces HSP25 dependency

The majority of colorectal cancers (CRCs) present with early mutations in tumor suppressor gene APC. APC mutations result in oncogenic activation of the Wnt pathway, which is associated with hyperproliferation, cytoskeletal remodeling, and a global increase in mRNA translation. To compensate for the increased biosynthetic demand, cancer cells critically depend on protein chaperones to maintain proteostasis, although their function in CRC remains largely unexplored. In order to investigate the role of molecular chaperones in driving CRC initiation, we captured the transcriptomic profiles of murine wild type and Apc-mutant organoids during active transformation. We discovered a strong transcriptional upregulation of Hspb1, which encodes small heat shock protein 25 (HSP25). We reveal an indispensable role for HSP25 in facilitating Apc-driven transformation, using both in vitro organoid cultures and mouse models, and demonstrate that chemical inhibition of HSP25 using brivudine reduces the development of premalignant adenomas. These findings uncover a hitherto unknown vulnerability in intestinal transformation that could be exploited for the development of chemopreventive strategies in high-risk individuals.

CircHADHA-augmented autophagy suppresses tumor growth of colon cancer by regulating autophagy-related gene via miR-361

Colon cancer undergoes a traditional pathway from colon polyps to colon cancer. It is of great significance to investigate the key molecules involved in carcinogenesis from polyps to malignancies. Circular RNAs (circRNAs) are stably expressed in human body fluids such as plasma. Here, we demonstrated a differential expression pattern of plasma circRNAs in healthy individuals, colon polyp patients and colon cancer patients using circRNA Arraystar microarray. We explored that circRNA HADHA (circHADHA) was upregulated in plasma from polyp patients, whereas it was downregulated in plasma from colon cancer patients. Overexpression of circHADHA promoted autophagy in colon epithelial cells. Moreover, in colon cancer cells, overexpression of circHADHA promoted autophagy, whereas it inhibited cell proliferation and colony formation. CircHADHA increased the expression of ATG13 via miR-361 in both colon epithelial and cancer cells. ATG13 knockdown reduced autophagy even in the presence of circHADHA in colon cancer cells. Furthermore, the growth of circHADHA-overexpressing colon cancer cell-derived xenograft tumors was significantly decreased compared with control tumors in nude mice. In conclusion, circHADHA was differentially expressed in the plasma of healthy individuals, colon polyp patients and colon cancer patients. CircHADHA promoted autophagy by regulating ATG13 via miR-361 in both colon epithelial and cancer cells. CircHADHA suppressed tumor growth by inducing cell autophagy in colon cancer cells. CircHADHA potentially serves as a biomarker for screening of precursor colon cancer and a therapeutic target for colon cancer treatment.

Sequential Accumulation of ‘Driver’ Pathway Mutations Induces the Upregulation of Hydrogen-Sulfide-Producing Enzymes in Human Colonic Epithelial Cell Organoids

Recently, a CRISPR-Cas9 genome-editing system was developed with introduced sequential ‘driver’ mutations in the WNT, MAPK, TGF-β, TP53 and PI3K pathways into organoids derived from normal human intestinal epithelial cells. Prior studies have demonstrated that isogenic organoids harboring mutations in the tumor suppressor genes APC, SMAD4 and TP53, as well as the oncogene KRAS, assumed more proliferative and invasive properties in vitro and in vivo. A separate body of studies implicates the role of various hydrogen sulfide (H2S)-producing enzymes in the pathogenesis of colon cancer. The current study was designed to determine if the sequential mutations in the above pathway affect the expression of various H2S producing enzymes. Western blotting was used to detect the expression of the H2S-producing enzymes cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), as well as several key enzymes involved in H2S degradation such as thiosulfate sulfurtransferase/rhodanese (TST), ethylmalonic encephalopathy 1 protein/persulfide dioxygenase (ETHE1) and sulfide-quinone oxidoreductase (SQR). H2S levels were detected by live-cell imaging using a fluorescent H2S probe. Bioenergetic parameters were assessed by Extracellular Flux Analysis; markers of epithelial-mesenchymal transition (EMT) were assessed by Western blotting. The results show that the consecutive mutations produced gradual upregulations in CBS expression—in particular in its truncated (45 kDa) form—as well as in CSE and 3-MST expression. In more advanced organoids, when the upregulation of H2S-producing enzymes coincided with the downregulation of the H2S-degrading enzyme SQR, increased H2S generation was also detected. This effect coincided with the upregulation of cellular bioenergetics (mitochondrial respiration and/or glycolysis) and an upregulation of the Wnt/β-catenin pathway, a key effector of EMT. Thus sequential mutations in colon epithelial cells according to the Vogelstein sequence are associated with a gradual upregulation of multiple H2S generating pathways, which, in turn, translates into functional changes in cellular bioenergetics and dedifferentiation, producing more aggressive and more invasive colon cancer phenotypes.

Colorectal cancers with a residual adenoma component: Clinicopathologic features and KRAS mutation

Background/Aim

Colorectal cancer is well known for its “adenoma-carcinoma” sequential carcinogenesis. Some colorectal cancers demonstrate a residual adenoma component during progression from adenoma to invasive carcinoma. However, the clinicopathological significance of residual adenoma component remains unclear. In this study, we aimed to investigate the clinicopathologic and molecular characteristics including the KRAS mutation in colorectal cancers containing a residual adenoma component.

Materials and methods

In this study, 498 surgically resected colorectal cancer patients were enrolled. Their detailed clinicopathologic features and results of molecular study including KRAS mutation test and microsatellite instability were analyzed.

Results

A residual adenoma component was identified in 42 (8.4%) patients with colorectal cancer. The presence of a residual adenoma component was associated with a high frequency of the KRAS mutation (65%, p = 0.031) as well as indolent clinicopathological features, including polypoid gross type (p < 0.001), well-differentiated histology (p < 0.001), low pT (p < 0.001) and pN stage (p = 0.003), absence of vascular invasion (p = 0.005), and a better progression-free prognosis (p = 0.029). The cases with an adenoma component had a 35.7% discordance rate on the KRAS mutation tests in their adenoma and carcinoma regions.

Conclusion

In conclusion, colorectal cancer with a residual adenoma component showed indolent clinicopathologic features and frequent KRAS mutations. Due to the discordance in the incidence of the KRAS mutation between the adenoma and carcinoma components, the adenoma component should be documented in the pathology report, and care should be taken not to include the adenoma component when collecting samples for molecular testing.

The Anticancer Effects of the Pro-Apoptotic Benzofuran-Isatin Conjugate (5a) Are Associated With p53 Upregulation and Enhancement of Conventional Chemotherapeutic Drug Efficiency in Colorectal Cancer Cell Lines

The present study aimed to investigate in-depth a cytotoxic novel benzofuran-isatin conjugate (5a, 3-methyl-N'-(2-oxoindolin-3-ylidene)benzofuran-2-carbohydrazide) with promising potential anticancer activities in colorectal adenocarcinoma HT29 and metastatic colorectal cancer (CRC) SW620 cell lines. Thus, the primary cell events involved in tumorigenicity, tumor development, metastasis, and chemotherapy response were explored. Both CRC cell lines were exposed to different concentrations of Compound 5a and then subjected to real-time cell viability, migration, and invasion assays, colony formation and cytotoxicity assays, and flow cytometry for cell cycle analysis and apoptosis determination. Western blot and RT-qPCR were performed to assess the protein and transcript expression levels of epithelial-mesenchymal transition (EMT), cell cycle, and apoptosis markers. We showed that the Compound 5a treatment exhibited anticancer effects through inhibition of HT29 and SW620 cell viability, migration, and invasion, in a dose-dependent manner, which were associated with the upregulation of the tumor suppressor p53. Compound 5a also inhibited the colony formation ability of HT29 and SW620 cells and reversed EMT markers E-cadherin and N-cadherin expression. CRC cell exposure to Compound 5a resulted in a cell cycle arrest at the G1/G0 phase in HT29 cells and at the G2/M phase in SW620 cells, along with the downregulation of cyclin A1 expression, described to be involved in the S phase entry. Furthermore, Compound 5a-induced apoptosis was associated with the downregulation of the anti-apoptotic Bcl-xl marker, upregulation of pro-apoptotic Bax and cytochrome c markers, and increased mitochondrial outer membrane permeability, suggesting the involvement of mitochondria-dependent apoptosis pathway. In addition, the combination studies of Compound 5a with the main conventional chemotherapeutic drugs 5-fluorouracil, irinotecan, and oxaliplatin showed a more potent cytotoxic effect in both CRC cells than a single treatment. In conclusion, our findings described the interesting in vitro anticancer properties of Compound 5a, shown to have possible antitumor, antimetastatic, and pro-apoptotic activities, with the enhancement of the cytotoxic efficiency of conventional chemotherapeutic drugs. In vivo studies are requested to confirm the promising anticancer potential of Compound 5a for CRC therapy.

Aspirin sensitivity of PIK3CA-mutated Colorectal Cancer: potential mechanisms revisited

PIK3CA mutations are amongst the most prevalent somatic mutations in cancer and are associated with resistance to first-line treatment along with low survival rates in a variety of malignancies. There is evidence that patients carrying PIK3CA mutations may benefit from treatment with acetylsalicylic acid, commonly known as aspirin, particularly in the setting of colorectal cancer. In this regard, it has been clarified that Class IA Phosphatidylinositol 3-kinases (PI3K), whose catalytic subunit p110α is encoded by the PIK3CA gene, are involved in signal transduction that regulates cell cycle, cell growth, and metabolism and, if disturbed, induces carcinogenic effects. Although PI3K is associated with pro-inflammatory cyclooxygenase-2 (COX-2) expression and signaling, and COX-2 is among the best-studied targets of aspirin, the mechanisms behind this clinically relevant phenomenon are still unclear. Indeed, there is further evidence that the protective, anti-carcinogenic effect of aspirin in this setting may be mediated in a COX-independent manner. However, until now the understanding of aspirin's prostaglandin-independent mode of action is poor. This review will provide an overview of the current literature on this topic and aims to analyze possible mechanisms and targets behind the aspirin sensitivity of PIK3CA-mutated cancers.

Clonal evolution and expansion associated with therapy resistance and relapse of colorectal cancer

Colorectal cancer (CRC) arises by a continuous process of genetic diversification and clonal evolution. Multiple genes and pathways have a role in tumor initiation and progression. The gradual accumulation of genetic and epigenetic processes leads to the establishment of adenoma and cancer. The important 'driver' mutations in tumor suppressor genes (such as TP53, APC, and SMAD4) and oncogenes (such as KRAS, NRAS, MET, and PIK3CA) confer selective growth advantages and cause CRC advancement. Clonal evolution induced by therapeutic pressure, as well as intra-tumoral heterogeneity, has been a great challenge in the treatment of metastatic CRC. Tumors often develop resistance to treatments as a result of intra-tumor heterogeneity, clonal evolution, and selection. Hence, the development of a multidrug personalized approach should be prioritized to pave the way for therapeutics repurposing and combination therapy to arrest tumor progression. This review summarizes how selective drug pressure can impact tumor evolution, resulting in the formation of polyclonal resistance mechanisms, ultimately promoting cancer progression. Current strategies for targeting clonal evolution are described. By understanding sources and consequences of tumor heterogeneity, customized and effective treatment plans to combat drug resistance may be devised.

Relationship between gene mutations and clinicopathological features in nonampullary duodenal epithelial tumors

BACKGROUND

Molecular features of nonampullary duodenal epithelial tumors (NADETs) remain unclear.

AIM

The aim of this study is to determine the association between the genetic features and clinicopathological findings of NADETs.

METHODS

In total, 75 NADETs were enrolled in this study, and was performed targeted DNA sequencing of the GNAS, KRAS, TP53, and APC genes. Histological grade was classified as category 3 or category 4/5 according to the Vienna classification, and the immunophenotype was categorized as the gastric phenotype (G type), gastrointestinal phenotype (GI type), or the intestinal phenotype (I type).

RESULTS

The prevalence of GNAS and KRAS mutations was significantly higher in the G type than in the GI/I type (GNAS, P = 0.027; KRAS, P = 0.005). In contrast, the frequency of TP53 mutations was significantly higher in the GI/I type than in the G type (P = 0.049). Notably, APC mutations, excluding c.4479 G>A which was synonymous mutation, were more frequently identified in category 4/5 tumors than in category 3 tumors (50% vs. 24.5%; P = 0.039).

CONCLUSION

G-type NADETs harbored frequent GNAS and KRAS mutations, whereas TP53 mutations are common in NADETs with intestinal features. APC mutations were significantly associated with high-grade neoplasia and invasive carcinoma.

Mechanobiology of Colorectal Cancer

Simple Summary

It is well documented that colorectal cancer (CRC) is the third most common cancer type, responsible for high mortality in developed countries, resulting in a high socio-economic impact. Several biochemical and gene expression pathways explaining the manifestation of this cancer in humans have already been identified. However, explanations for some of the related biophysical mechanisms and their influence on CRC remain elusive. In CRC, biophysics and medical research have already revealed the importance of studying the effects of the stiffness and viscoelasticity of the substrate on cells, as well as the effect of the shear stress of blood and lymphatic vessels on the behavior of cells and tissues. A deeper understanding of the relationship between the biophysical cues and biochemical signals could be advantageous to develop new diagnostic techniques and therapeutic strategies. Being a disease with a high mortality rate, it becomes crucial to dedicate efforts to finding effective, alternative therapeutic strategies.

Abstract

In this review, the mechanobiology of colorectal cancer (CRC) are discussed. Mechanotransduction of CRC is addressed considering the relationship of several biophysical cues and biochemical pathways. Mechanobiology is focused on considering how it may influence epithelial cells in terms of motility, morphometric changes, intravasation, circulation, extravasation, and metastization in CRC development. The roles of the tumor microenvironment, ECM, and stroma are also discussed, taking into account the influence of alterations and surface modifications on mechanical properties and their impact on epithelial cells and CRC progression. The role of cancer-associated fibroblasts and the impact of flow shear stress is addressed in terms of how it affects CRC metastization. Finally, some insights concerning how the knowledge of biophysical mechanisms may contribute to the development of new therapeutic strategies and targeting molecules and how mechanical changes of the microenvironment play a role in CRC disease are presented.

Risk Factors for Colorectal Polyps and Cancer

Colorectal cancer (CRC) is a common malignancy in the U.S. and worldwide. Most CRC cases arise from precancerous adenomatous and serrated polyps. Established risk factors for conventional adenomas and CRC include age, male sex, family history, obesity and physical inactivity, and red meat intake. White race and tobacco and alcohol use are important risk factors for serrated polyps, which have a distinct risk factor profile compared to conventional adenomas. A history of abdominopelvic radiation, acromegaly, hereditary hemochromatosis, or prior ureterosigmoidostomy also increases CRC risk. Understanding these risk factors allows for targeted screening of high-risk groups to reduce CRC incidence.

Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.

Application Progress of Organoids in Colorectal Cancer

Currently, colorectal cancer is still the third leading cause of cancer-related mortality, and the incidence is rising. It is a long time since the researchers used cancer cell lines and animals as the study subject. However, these models possess various limitations to reflect the cancer progression in the human body. Organoids have more clinical significance than cell lines, and they also bridge the gap between animal models and humans. Patient-derived organoids are three-dimensional cultures that simulate the tumor characteristics in vivo and recapitulate tumor cell heterogeneity. Therefore, the emergence of colorectal cancer organoids provides an unprecedented opportunity for colorectal cancer research. It retains the molecular and cellular composition of the original tumor and has a high degree of homology and complexity with patient tissues. Patient-derived colorectal cancer organoids, as personalized tumor organoids, can more accurately simulate colorectal cancer patients’ occurrence, development, metastasis, and predict drug response in colorectal cancer patients. Colorectal cancer organoids show great potential for application, especially preclinical drug screening and prediction of patient response to selected treatment options. Here, we reviewed the application of colorectal cancer organoids in disease model construction, basic biological research, organoid biobank construction, drug screening and personalized medicine, drug development, drug toxicity and safety, and regenerative medicine. In addition, we also displayed the current limitations and challenges of organoids and discussed the future development direction of organoids in combination with other technologies. Finally, we summarized and analyzed the current clinical trial research of organoids, especially the clinical trials of colorectal cancer organoids. We hoped to lay a solid foundation for organoids used in colorectal cancer research.

The gut microbiota can orchestrate the signaling pathways in colorectal cancer

Current evidence suggests that bacteria contribute to the development of certain cancers, such as colorectal cancer (CRC), partly by stimulating chronic inflammation. However, little is known about the bacterial impact on molecular pathways in CRC. Recent studies have demonstrated how specific bacteria can influence the major CRC-related pathways, i.e., Wnt, PI3K-Akt, MAPK, TGF-β, EGFR, mTOR, and p53. In order to advance the current understanding and facilitate the choice of pathways to investigate, we have systematically collected and summarized the current knowledge within bacterial altered major pathways in CRC. Several pro-tumorigenic and anti-tumorigenic bacterial species and their respective metabolites interfere with the major signaling pathways addressed in this review. Not surprisingly, some of these studies investigated known CRC drivers, such as Escherichia coli, Fusobacterium nucleatum, and Bacteroides fragilis. Interestingly, some metabolites produced by bacterial species typically considered pathogenic, e.g., Vibrio cholera, displayed anti-tumorigenic activities, emphasizing the caution needed when classifying healthy and unhealthy microorganisms. The results collectively emphasize the complexity of the relationship between the microbiota and the tumorigenesis of CRC, and future studies should verify these findings in more realistic models, such as organoids, which constitute a promising platform. Moreover, future trials should investigate the clinical potential of preventive modulation of the gut microbiota regarding CRC development.

Rpl24Bst mutation suppresses colorectal cancer by promoting eEF2 phosphorylation via eEF2K

Increased protein synthesis supports the rapid cell proliferation associated with cancer. The Rpl24Bst mutant mouse reduces the expression of the ribosomal protein RPL24 and has been used to suppress translation and limit tumorigenesis in multiple mouse models of cancer. Here, we show that Rpl24Bst also suppresses tumorigenesis and proliferation in a model of colorectal cancer (CRC) with two common patient mutations, Apc and Kras. In contrast to previous reports, Rpl24Bst mutation has no effect on ribosomal subunit abundance but suppresses translation elongation through phosphorylation of eEF2, reducing protein synthesis by 40% in tumour cells. Ablating eEF2 phosphorylation in Rpl24Bst mutant mice by inactivating its kinase, eEF2K, completely restores the rates of elongation and protein synthesis. Furthermore, eEF2K activity is required for the Rpl24Bst mutant to suppress tumorigenesis. This work demonstrates that elevation of eEF2 phosphorylation is an effective means to suppress colorectal tumorigenesis with two driver mutations. This positions translation elongation as a therapeutic target in CRC, as well as in other cancers where the Rpl24Bst mutation has a tumour suppressive effect in mouse models.

Insights into the Role of Matrix Metalloproteinases in Precancerous Conditions and in Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is one of the most common cancer worldwide. CRC is derived from polyps and many factors, such as Matrix Metalloproteinases (MMPs) can gain the progression of colorectal carcinogenesis. Many investigations have indicated the role of MMPs in CRC development while there is not enough knowledge about the function of MMPs in precancerous conditions. This review summarizes the current information about the role of MMPs in polyps and CRC progression.

Abstract

Colorectal cancer (CRC) is the third and second cancer for incidence and mortality worldwide, respectively, and is becoming prevalent in developing countries. Most CRCs derive from polyps, especially adenomatous polyps, which can gradually transform into CRC. The family of Matrix Metalloproteinases (MMPs) plays a critical role in the initiation and progression of CRC. Prominent MMPs, including MMP-1, MMP-2, MMP-7, MMP-8, MMP-9, MMP-12, MMP-13, MMP-14, and MMP-21, have been detected in CRC patients, and the expression of most of them correlates with a poor prognosis. Moreover, many studies have explored the inhibition of MMPs and targeted therapy for CRC, but there is not enough information about the role of MMPs in polyp malignancy. In this review, we discuss the role of MMPs in colorectal cancer and its pathogenesis

BCL-XL is crucial for progression through the adenoma-to-carcinoma sequence of colorectal cancer

Evasion of apoptosis is a hallmark of cancer, which is frequently mediated by upregulation of the antiapoptotic BCL-2 family proteins. In colorectal cancer (CRC), previous work has highlighted differential antiapoptotic protein dependencies determined by the stage of the disease. While intestinal stem cells (ISCs) require BCL-2 for adenoma outgrowth and survival during transformation, ISC-specific MCL1 deletion results in disturbed intestinal homeostasis, eventually contributing to tumorigenesis. Colon cancer stem cells (CSCs), however, no longer require BCL-2 and depend mainly on BCL-XL for their survival. We therefore hypothesized that a shift in antiapoptotic protein reliance occurs in ISCs as the disease progresses from normal to adenoma to carcinoma. By targeting antiapoptotic proteins with specific BH3 mimetics in organoid models of CRC progression, we found that BCL-2 is essential only during ISC transformation while MCL1 inhibition did not affect adenoma outgrowth. BCL-XL, on the other hand, was crucial for stem cell survival throughout the adenoma-to-carcinoma sequence. Furthermore, we identified that the limited window of BCL-2 reliance is a result of its downregulation by miR-17-5p, a microRNA that is upregulated upon APC-mutation driven transformation. Here we show that BCL-XL inhibition effectively impairs adenoma outgrowth in vivo and enhances the efficacy of chemotherapy. In line with this dependency, expression of BCL-XL, but not BCL-2 or MCL1, directly correlated to the outcome of chemotherapy-treated CRC patients. Our results provide insights to enable the rational use of BH3 mimetics in CRC management, particularly underlining the therapeutic potential of BCL-XL targeting mimetics in both early and late-stage disease.

Monocyte Chemotactic Proteins (MCP) in Colorectal Adenomas Are Differently Expressed at the Transcriptional and Protein Levels: Implications for Colorectal Cancer Prevention

The expression of monocyte chemotactic proteins (MCPs) in colorectal polyps and their suitability as targets for chemoprevention is unknown, although MCP expression and secretion can be modulated by non-steroidal inflammatory drugs. This study was designed to determine the expression patterns of MCP-1/CCL2, MCP-2/CCL8, and MCP-3/CCL7 at the protein (immunohistochemistry; n = 62) and transcriptional levels (RTqPCR; n = 173) in colorectal polyps with reference to the polyp malignancy potential. All chemokines were significantly upregulated in polyps at the protein level but downregulated at the transcriptional level by 1.4-(CCL2), 1.7-(CCL7), and 2.3-fold (CCL8). There was an inverse relation between the immunoreactivity toward chemokine proteins and the number of corresponding transcripts in polyps (CCL2 and CCL7) or in normal mucosa (CCL8). The downregulation of chemokine transcripts correlated with the presence of multiple polyps (CCL2 and CCL8), a larger polyp size (CCL2, CCL7, and CCL8), predominant villous growth patterns (CCL2, CCL7 and CCL8), and high-grade dysplasia (CCL2 and CCL8). In conclusion, MCP-1/CCL2, MCP-2/CCL8, and MCP-3/CCL7 chemokines are counter-regulated at the protein and transcriptional levels. Chemokine-directed chemopreventive strategies should therefore directly neutralize MCP proteins or target molecular pathways contributing to their enhanced translation or reduced degradation, rather than aiming at CCL2, CCL7 or CCL8 expression.

Artificial intelligence reveals roles of gut microbiota in driving human colorectal cancer evolution

With the rapid development of high-throughput sequencing and artificial intelligence (AI) techniques, gut mucosal microbiota begins to be recognized as critical drivers of human colorectal cancer (CRC). Various AI approaches have been designed to obtain effective information from enormous numbers of microbial cells residing in gut mucosal as well as cancer cells. These mainly include detection of microbial markers for early clinical diagnosis of stage-specific CRC, characterization of pathogenic bacterial activities via genomic and transcriptomic analyses, and prediction of interplay between bacterial drivers and host immune systems. Here I review the current progresses of AI applications in profiling gut microbiomes linked to CRC initiation and development. I further look forward to future AI research for improving our understanding of the roles of gut microbiota in CRC evolution.

Clinicopathologic Characteristics of FBXW7-Mutated Colorectal Adenocarcinoma and Association with Aberrant Beta-catenin Localization

Oncogenic mutations in the adenomatous polyposis coli (APC)/Wnt signaling pathway are well documented. The FBXW7 gene (F-Box And WD Repeat Domain Containing 7) encodes a member of the ubiquitin-proteasome complex that is more recently described to antagonize the oncogenic Wnt pathway by promoting the degradation of β-catenin encoded by CTNNB1 gene. The pathologic significance of FBXW7 mutation in colorectal carcinoma (CRC) remains underreported. In this study, we report the clinicopathologic and β-catenin immunohistochemical features of a single-institution cohort (83 cases) of FBXW7-mutated CRC compared to CTNNB1-mutated CRC. FBXW7-mutated CRC was more common in older patients (p=0.031) and in the left/distal colon (p=0.022). Immunohistochemical analysis revealed that aberrant nuclear/cytoplasmic β-catenin localization was identified in a significantly high proportion of FBXW7-mutated CRCs. When compared to CTNNB1-mutated CRC, FBXW7-mutated CRC showed a significantly higher proportion of MSI-stable tumors with intact expression of DNA mismatch repair proteins, and had significantly more frequent co-occurrence of missense TP53 and KRAS mutations. The most frequently mutated FBXW7 residues/hotspots were located within the WD repeat domains (aa 378-659), which were also associated with aberrant nuclear/cytoplasmic localization of β-catenin protein. Our results indicate the unique pathologic characteristics of FBXW7 mutated CRC with frequent co-occurrence of missense mutant TP53, and KRAS. The mutated FBXW7 residues/hotspots and its association with aberrant nuclear/cytoplasmic β-catenin localization further support the oncogenic role of FBXW7 in colon carcinogenesis.

The concerted action of oncogenic driver mutations directs global translation in intestinal epithelial cells

Oncogenic transformation of colorectal cancer cells is driven by a set of mutations that cause aberrant signaling of growth factor-receptor pathways. Using organoids, we demonstrate that the most frequent driver mutations in APC, KRAS, SMAD4, and TP53 are enhancers of the global mRNA translational capacity, which is linked to intestinal cell growth in an mTOR-dependent manner.

Epithelial argininosuccinate synthetase is dispensable for intestinal regeneration and tumorigenesis

The epithelial signaling pathways involved in damage and regeneration, and neoplastic transformation are known to be similar. We noted upregulation of argininosuccinate synthetase (ASS1) in hyperproliferative intestinal epithelium. Since ASS1 leads to de novo synthesis of arginine, an important amino acid for the growth of intestinal epithelial cells, its upregulation can contribute to epithelial proliferation necessary to be sustained during oncogenic transformation and regeneration. Here we investigated the function of ASS1 in the gut epithelium during tissue regeneration and tumorigenesis, using intestinal epithelial conditional Ass1 knockout mice and organoids, and tissue specimens from colorectal cancer patients. We demonstrate that ASS1 is strongly expressed in the regenerating and Apc-mutated intestinal epithelium. Furthermore, we observe an arrest in amino acid flux of the urea cycle, which leads to an accumulation of intracellular arginine. However, loss of epithelial Ass1 does not lead to a reduction in proliferation or increase in apoptosis in vivo, also in mice fed an arginine-free diet. Epithelial loss of Ass1 seems to be compensated by altered arginine metabolism in other cell types and the liver.

Distinguishing colorectal adenoma from hyperplastic polyp by WNT2 expression

BACKGROUND

Colorectal adenoma (CRA) is a classical premalignant lesion, with high incidence and mainly coexisting with hyperplastic polyp (HPP). Hence, this study aimed to distinguish CRA from HPP by molecular expression profiling and advance the prevention of CRA and its malignance.

METHODS

CRA and paired HPP biopsies were collected by endoscopy. Through RNA-sequencing (RNA-seq), the differentially expressed genes (DEGs) were obtained. Functional enrichment analysis was performed based on the DEGs. The STRING database and Cytoscape were used to construct the protein-protein interaction (PPI) network and perform module analysis. Hub genes were validated by real-time quantitative PCR (RT-qPCR) and immunohistochemistry. The ROC curve was drawn to establish the specificity of the hub genes.

RESULTS

485 significant DEGs were identified including 133 up-regulated and 352 down-regulated. The top 10 up-regulated genes were DLX5, MMP10, TAC1, ACAN, TAS2R38, WNT2, PHYHIPL, DKK4, DUSP27, and ABCA12. The top 10 down-regulated genes were SFRP2, CHRDL1, KBTBD12, RERGL, DPP10, CLCA4, GREM2, TMIGD1, FEV, and OTOP3. Wnt signaling pathway and extracellular matrix (ECM) were up-regulated in CRA. Three hub genes including WNT2, WNT5A, and SFRP1 were filtered out via Cytoscape. Further RT-qPCR and immunohistochemistry confirmed that WNT2 was highly expressed in CRA. The area under the ROC curve (AUC) at 0.98 indicated the expression level of WNT2 as a candidate to differ CRA from HPP.

CONCLUSION

Our study suggests Wnt signaling pathway and ECM are enriched in CRA, and WNT2 may be used as a novel biomarker for distinguishing CRA from HPP and preventing the malignance of CRA.

Collective behaviours in organoids

Collective behaviour emerges from interacting units within communities, such as migrating herds, swimming fish schools, and cells within tissues. At the microscopic level, collective behaviours include collective cell migration in development and cancer invasion, rhythmic gene expression in pattern formation, cell competition in homeostasis and cancer, force generation and mechano-sensing in morphogenesis. Studying the initiation and the maintenance of collective cell behaviours is key to understand the principles of development, regeneration and disease. However, the manifold influences of contributing factors in in vivo environments challenge the dissection of causalities in animal models. As an alternative model that has emerged to overcome this difficulty, in vitro three-dimensional organoid cultures provide a reductionist approach yet retain similarities with the in vivo tissue in cellular composition and tissue organisation. Here, we focus on recent progresses in studying collective behaviours in different organoid systems and discuss their advantages and the possibility of improvement for future applications.

Translation initiation factor eIF2Bε promotes Wnt-mediated clonogenicity and global translation in intestinal epithelial cells

Modulation of global mRNA translation, which is essential for intestinal stem cell function, is controlled by Wnt signaling. Loss of tumor supressor APC in stem cells drives adenoma formation through hyperactivion of Wnt signaling and dysregulated translational control. It is unclear whether factors that coordinate global translation in the intestinal epithelium are needed for APC-driven malignant transformation. Here we identified nucleotide exchange factor eIF2Bε as a translation initiation factor involved in Wnt-mediated intestinal epithelial stemness. Using eIF2Bε^Arg191His mice with a homozygous point mutation that leads to dysfunction in the enzymatic activity, we demonstrate that eIF2Bε is involved in small intestinal crypt formation, stemness marker expression, and secreted Paneth cell-derived granule formation. Wnt hyperactivation in ex vivo eIF2Bε^Arg191His organoids, using a GSK3β inhibitor to mimic Apc driven transformation, shows that eIF2Bε is essential for Wnt-mediated clonogenicity and associated increase of the global translational capacity. Finally, we observe high eIF2Bε expression in human colonic adenoma tissues, exposing eIF2Bε as a potential target of CRC stem cells with aberrant Wnt signaling.

The Role of p53 Dysfunction in Colorectal Cancer and Its Implication for Therapy

Colorectal cancer (CRC) is one of the most common and fatal cancers worldwide. The carcinogenesis of CRC is based on a stepwise accumulation of mutations, leading either to an activation of oncogenes or a deactivation of suppressor genes. The loss of genetic stability triggers activation of proto-oncogenes (e.g., KRAS) and inactivation of tumor suppression genes, namely TP53 and APC, which together drive the transition from adenoma to adenocarcinoma. On the one hand, p53 mutations confer resistance to classical chemotherapy but, on the other hand, they open the door for immunotherapy, as p53-mutated tumors are rich in neoantigens. Aberrant function of the TP53 gene product, p53, also affects stromal and non-stromal cells in the tumor microenvironment. Cancer-associated fibroblasts together with other immunosuppressive cells become valuable assets for the tumor by p53-mediated tumor signaling. In this review, we address the manifold implications of p53 mutations in CRC regarding therapy, treatment response and personalized medicine.

KRASG12C Can Either Promote or Impair Cap-Dependent Translation in Two Different Lung Adenocarcinoma Cell Lines

KRAS^G12C is among the most common oncogenic mutations in lung adenocarcinoma and a promising target for treatment by small-molecule inhibitors. KRAS oncogenic signaling is responsible for modulation of tumor microenvironment, with translation factors being among the most prominent deregulated targets. In the present study, we used TALENs to edit EGFR^WT CL1-5 and A549 cells for integration of a Tet-inducible KRAS^G12C expression system. Subsequent analysis of both cell lines showed that cap-dependent translation was impaired in CL1-5 cells via involvement of mTORC2 and NF-κB. In contrast, in A549 cells, which additionally harbor the KRAS^G12S mutation, cap-dependent translation was favored via recruitment of mTORC1, c-MYC and the positive regulation of eIF4F complex. Downregulation of eIF1, eIF5 and eIF5B in the same cell line suggested a stringency loss of start codon selection during scanning of mRNAs. Puromycin staining and polysome profile analysis validated the enhanced translation rates in A549 cells and the impaired cap-dependent translation in CL1-5 cells. Interestingly, elevated translation rates were restored in CL1-5 cells after prolonged induction of KRAS^G12C through an mTORC1/p70S6K-independent way. Collectively, our results suggest that KRAS^G12C signaling differentially affects the regulation of the translational machinery. These differences could provide additional insights and facilitate current efforts to effectively target KRAS.

Tuning protein synthesis for cancer therapy

~50% of colorectal cancers have an activating mutation in KRAS (encoding the KRAS proto-oncogene) and remain difficult to target in the clinic. We have recently shown that activation of KRAS protein alters the regulation of mRNA translation, increasing total protein synthesis, and maintaining elevated c-MYC (MYC proto-oncogene) expression. Targeting these pathways downstream of KRAS reveals a striking dependency that has potential for clinical translation.