APC Mutation Marks an Aggressive Subtype of BRAF Mutant Colorectal Cancers

New insights in ubiquitin-dependent Wnt receptor regulation in tumorigenesis

Wnt signaling plays a crucial role in embryonic development and homeostasis maintenance. Delicate and sensitive fine-tuning of Wnt signaling based on the proper timings and positions is required to balance cell proliferation and differentiation and maintain individual health. Therefore, homeostasis is broken by tissue hypoplasia or tumor formation once Wnt signal dysregulation disturbs the balance of cell proliferation. The well-known regulatory mechanism of Wnt signaling is the molecular reaction associated with the cytoplasmic accumulation of effector β-catenin. In addition to β-catenin, most Wnt effector proteins are also regulated by ubiquitin-dependent modification, both qualitatively and quantitatively. This review will explain the regulation of the whole Wnt signal in four regulatory phases, as well as the different ubiquitin ligases and the function of deubiquitinating enzymes in each phase. Along with the recent results, the mechanism by which RNF43 negatively regulates the surface expression of Wnt receptors, which has recently been well understood, will be detailed. Many RNF43 mutations have been identified in pancreatic and gastrointestinal cancers and examined for their functional alteration in Wnt signaling. Several mutations facilitate or activate the Wnt signal, reversing the RNF43 tumor suppressor function into an oncogene. RNF43 may simultaneously play different roles in classical multistep tumorigenesis, as both wild-type and mutant RNF43 suppress the p53 pathway. We hope that the knowledge obtained from further research in RNF43 will be applied to cancer treatment in the future despite the fully unclear function of RNF43.

Association of RNF43 Genetic Alterations With BRAFV600E and MSIhigh in Colorectal Cancer

PURPOSE

Recent studies have provided evidence for a predictive value of RNF43 genetic alterations (GAs) as biomarkers for targeted therapies in microsatellite-stable (MSS) colorectal cancer (CRC). These data have the potential to prioritize treatment strategies in patients with BRAFV600E-mutant CRC and help to identify a subgroup that is more likely to derive benefit versus those patients for whom alternative treatment approaches are needed. We were therefore interested in defining the precise frequency of BRAFV600E and RNF43 GAs and their respective overlap in a large cohort of patients with CRC.

METHODS

To address this question, we performed a retrospective analysis that included 52,969 patients diagnosed with CRC from the FoundationCORE database.

RESULTS

We observed a striking association of RNF43 GAs with MSI and tumor mutational burden status and BRAFV600E mutations. Overall, 23% of MSS patients with confirmed BRAFV600E mutation harbor an RNF43 GA-which accounts for 1.1% of all patients with CRC and for 15.7% of all CRC BRAFV600E cases.

CONCLUSION

Ongoing phase III clinical trials, such as BREAKWATER, should aim to incorporate broader genetic profiling to further validate the superior sensitivity of patients with RNF43-mutant, MSS BRAFV600E CRC to anti-EGFR-/BRAFi-based therapies.

Clinical and molecular characteristics of RNF43 mutations as promising prognostic biomarkers in colorectal cancer

Background

Transmembrane E3 ubiquitin ligase (RNF43) mutations are present in approximately 6-18% of colorectal cancers (CRC) and could enhance Wnt/β-catenin signaling, which is emerging as a promising therapeutic target. This study aims to investigate the clinical and molecular characteristics and potential heterogeneity of RNF43-mutant CRC.

Methods

A total of 78 patients with RNF43-mutant CRC were enrolled from July 2013 to November 2022. Demographic data, clinical characteristics, treatment regimens used, and survival outcomes were collected and analyzed.

Results

Our study uncovered that patients with RNF43 mutations in the N-terminal domain (NTD; n = 50) exhibited shorter overall survival (OS; median months, 50.80 versus not reached; p = 0.043) compared to those in the C-terminal domain (CTD; n = 17). Most RNF43 mutations in NTD had positive primary lymph node status, low tumor mutation burden (TMB-L), and correlated with proficient mismatch repair (pMMR)/microsatellite stable (MSS) status. By contrast, RNF43 mutations in CTD were significantly enriched in deficient MMR (dMMR)/microsatellite instability (MSI-H) tumors with high TMB (TMB-H). N-terminal RNF43-mutated tumors harbored a hotspot variant (RNF43 R117fs), which independently predicted a significantly worse outcome in pMMR/MSS CRC with a median OS of 18.9 months. Patients with RNF43 mutations and the BRAF V600E alterations demonstrated sensitivity to BRAF/EGFR inhibitors. Moreover, we observed that pMMR/MSS patients with RNF43 R117fs mutation had a higher incidence of stage IV, ⩾2 metastatic sites, low TMB, and none of them received PD-1/PD-L1 inhibitor therapy.

Conclusion

Our findings provide the first evidence that RNF43 mutations in NTD and the R117fs variant correlate with a poorer prognosis in CRC patients, providing strategies for Wnt-targeted therapy to improve clinical efficacy.

Leveraging a disulfidptosis‑related lncRNAs signature for predicting the prognosis and immunotherapy of glioma

BACKGROUND

Gliomas, a prevalent form of primary brain tumors, are linked with a high mortality rate and unfavorable prognoses. Disulfidptosis, an innovative form of programmed cell death, has received scant attention concerning disulfidptosis-related lncRNAs (DRLs). The objective of this investigation was to ascertain a prognostic signature utilizing DRLs to forecast the prognosis and treatment targets of glioma patients.

METHODS

RNA-seq data were procured from The Cancer Genome Atlas database. Disulfidptosis-related genes were compiled from prior research. An analysis of multivariate Cox regression and the least absolute selection operator was used to construct a risk model using six DRLs. The risk signature's performance was evaluated via Kaplan-Meier survival curves and receiver operating characteristic curves. Additionally, functional analysis was carried out using GO, KEGG, and single-sample GSEA to investigate the biological functions and immune infiltration. The research also evaluated tumor mutational burden, therapeutic drug sensitivity, and consensus cluster analysis. Reverse transcription quantitative PCR was conducted to validate the expression level of DRLs.

RESULTS

A prognostic signature comprising six DRLs was developed to predict the prognosis of glioma patients. High-risk patients had significantly shorter overall survival than low-risk patients. The robustness of the risk model was validated by receiver operating characteristic curves and subgroup survival analysis. Risk model was used independently as a prognostic indicator for the glioma patients. Notably, the low-risk patients displayed a substantial decrease in the immune checkpoints, the proportion of immune cells, ESTIMATE and immune score. IC50 values from the different risk groups allowed us to discern three drugs for the treatment of glioma patients. Lastly, the potential clinical significance of six DRLs was determined.

CONCLUSIONS

A novel six DRLs signature was developed to predict prognosis and may provide valuable insights for patients with glioma seeking novel immunotherapy and targeted therapy.

Clinical research progress on BRAF V600E-mutant advanced colorectal cancer

Colorectal cancer is one of the malignant tumors that pose a serious threat to human health. A particularly bad prognosis might be expected for colorectal tumors with the unique molecular subtype BRAF V600E mutation. With the development of precision therapy, the advent of molecularly targeted therapies and immune checkpoint inhibitors has improved the outcome of intermediate to advanced colorectal cancer. However, the duration of drug benefit is usually short, and overall survival and progression-free survival remain suboptimal. Therefore, investigators are exploring more rational, safe, and effective drug combination regimens through clinical trials to provide longer survival for patients with such genetic mutations with metastatic colorectal cancer (mCRC). This article reviews the progress of clinical research on molecularly targeted drugs, immune checkpoint inhibitors, first-line chemotherapeutic agents, and different combination therapy regimens (including different targeted drug combinations, immune combination targeting, and chemotherapy combination targeting) for colorectal cancer patients with BRAF V600E mutation, which provides a reference for further in-depth clinical exploration of the treatment of colorectal cancer patients with BRAF V600E mutation.

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Metastasising ameloblastoma or ameloblastic carcinoma? A case report with mutation analyses

BACKGROUND

Ameloblastic carcinoma and metastasising ameloblastoma are rare epithelial odontogenic tumours with aggressive features. Distinguishing between these two lesions is often clinically difficult but necessary to predict tumour behaviour or to plan future therapy. Here, we provide a brief review of the literature available on these two types of lesions and present a new case report of a young man with an ameloblastoma displaying metastatic features. We also use this case to illustrate the similarities and differences between these two types of tumours and the difficulties of their differential diagnosis.

CASE PRESENTATION

Our histopathological analyses uncovered a metastasising tumour with features of ameloblastic carcinoma, which developed from the ameloblastoma. We profiled the gene expression of Wnt pathway members in ameloblastoma sample of this patient, because multiple molecules of this pathway are involved in the establishing of cell polarity, cell migration or for epithelial-mesenchymal transition during tumour metastasis to evaluate features of tumor behaviour. Indeed, we found upregulation of several cell migration-related genes in our patient. Moreover, we uncovered somatic mutation BRAF p.V600E with known pathological role in cancerogenesis and germline heterozygous FANCA p.S858R mutation, whose interpretation in this context has not been discussed yet.

CONCLUSIONS

In conclusion, we have uncovered a unique case of ameloblastic carcinoma associated with an alteration of Wnt signalling and the presence of BRAF mutation. Development of harmful state of our patient might be also supported by the germline mutation in one FANCA allele, however this has to be confirmed by further analyses.

RNF43 is associated with genomic features and clinical outcome in BRAF mutant colorectal cancer

Background

Colorectal cancer (CRC) patients with BRAF mutation have very poor prognosis. It is urgent to search for prognostic factors of BRAF mutant CRC. RNF43 is a ENF ubiquitin ligase of Wnt signaling. Mutation of RNF43 has been observed frequently in various types of human cancers. However, few studies have evaluated the role of RNF43 in CRC. The present study aimed to explore the impact of RNF43 mutations on molecular characteristics and prognosis in BRAF mutant CRC.

Methods

Samples of 261 CRC patients with BRAF mutation were retrospectively analyzed. Tumor tissue and matched peripheral blood samples were collected and subjected to targeted sequencing with a panel of 1021 cancer-related genes. The association of molecular characteristics and survival in patients were then analyzed. 358 CRC patients with BRAF mutation from the cBioPortal dataset were used for further confirmation.

Results

This study was inspired by a CRC patient with BRAF V600E and RNF43 co-mutation, who achieved a best remission of 70% and a progression free survival (PFS) of 13 months. Genomic analysis indicated that RNF43 mutation affected the genomic characteristics of patients with BRAF mutation, including microsatellite instability (MSI), tumor mutation burden (TMB) and the proportion of common gene mutations. Survival analysis showed that RNF43 mutation was a predictive biomarker for better PFS and OS in BRAF mutant CRC.

Conclusion

Collectively, we identified that RNF43 mutations were correlated with favorable genomic features, resulting in a better clinical outcome for BRAF mutant CRC patients.

Wingless/It/β-catenin signaling in liver metastasis from colorectal cancer: A focus on biological mechanisms and therapeutic opportunities

The liver is the most common site of metastases in patients with colorectal cancer. Colorectal liver metastases (CRLMs) are the result of molecular mechanisms that involve different cells of the liver microenvironment. The aberrant activation of Wingless/It (Wnt)/β-catenin signals downstream of Wnt ligands initially drives the oncogenic transformation of the colon epithelium, but also the progression of metastatization through the epithelial-mesenchymal transition/mesenchymal-epithelial transition interactions. In liver microenvironment, metastatic cells can also survive and adapt through dormancy, which makes them less susceptible to pro-apoptotic signals and therapies. Treatment of CRLMs is challenging due to its variability and heterogeneity. Advances in surgery and oncology have been made in the last decade and a pivotal role for Wnt/β-catenin pathway has been re-cognized in chemoresistance. At the state of art, there is a lack of clear understanding of why and how this occurs and thus where exactly the opportunities for developing anti-CRLMs therapies may lie. In this review, current knowledge on the involvement of Wnt signaling in the development of CRLMs was considered. In addition, an overview of useful biomarkers with a revision of surgical and non-surgical therapies currently accepted in the clinical practice for colorectal liver metastasis patients were provided.

Metastatic pattern is a prognostic factor in BRAFV600E mutant colorectal cancer

BACKGROUND

Despite recent advancements in the treatment of metastatic BRAF^V600E colorectal cancer (CRC), prognosis remains poor. However, a some patients with BRAF^V600E disease have superior outcomes compared to the overall cohort and the prognostic factors associated with this improved survival are not well understood.

METHODS

We conducted a single center retrospective review of patients with metastatic CRC and available next generation sequencing data. Patients with confirmed BRAF^V600E disease were selected for the final analysis. We collected baseline demographic characteristics, concurrent mutations, and metastatic pattern. The primary endpoint was overall survival (OS). Univariate and multivariable logistic regression was used to examine the association between baseline concurrent somatic mutations and sites of metastatic disease with survival.

RESULTS

Of 466 patients with metastatic CRC, 50 harbored BRAF^V600E disease and 42 were included in the final analysis. The median OS in this cohort was 18.7 months (95% CI: 5.55-31.8). There was no association between baseline concurrent somatic mutations and OS. On univariate analysis, patients with lymph node only disease at the time of metastatic disease were more likely to have longer OS (hazard ratio [HR] = 0.30, 95% CI: 0.09-0.98, p = 0.047) and patients with peritoneal disease were more likely to have shorter OS (HR = 2.78, 95% CI: 1.12-6.88, p = 0.03). However, these associations did not retain statistical significance on multivariable analysis.

CONCLUSIONS

The pattern of metastatic disease in BRAF^V600E CRC may be a prognostic factor and future studies are needed to better understand the underlying mechanisms and potentially change clinical practice for a select patient population.

MICROABSTRACT

Select patients with metastatic BRAF^V600E colorectal cancer may have better than expected survival but are not well characterized. We conducted a retrospective review of 42 patients with metastatic BRAF^V600E colorectal cancer and showed that lymph node only disease at the time of metastatic disease was associated with superior survival.

In Vitro and In Silico Study on the Impact of Chlorogenic Acid in Colorectal Cancer Cells: Proliferation, Apoptosis, and Interaction with β-Catenin and LRP6

Colorectal cancer mortality rate and highly altered proteins from the Wnt/β-catenin pathway increase the scientific community's interest in finding alternatives for prevention and treatment. This study aims to determine the biological effect of chlorogenic acid (CGA) on two colorectal cancer cell lines, HT-29 and SW480, and its interactions with β-catenin and LRP6 to elucidate a possible modulatory mechanism on the Wnt/β-catenin pathway. These effects were determined by propidium iodide and DiOC6 for mitochondrial membrane permeability, MitoTracker Red for mitochondrial ROS production, DNA content for cell distribution on cell cycle phases, and molecular docking for protein-ligand interactions and binding affinity. Here, it was found that CGA at 2000 µM significantly affects cell viability and causes DNA fragmentation in SW480 cells rather than in HT-29 cells, but in both cell lines, it induces ROS production. Additionally, CGA has similar affinity and interactions for LRP6 as niclosamide but has a higher affinity for both β-catenin sites than C2 and iCRT14. These results suggest a possible modulatory role of CGA over the Wnt/β-catenin pathway in colorectal cancer.

Development of an Accessible Gene Expression Bioinformatics Pipeline to Study Driver Mutations of Colorectal Cancer

Colorectal cancer (CRC) is a global cause of cancer-related mortality driven by genetic and environmental factors which influence therapeutic outcomes. The emergence of next-generation sequencing technologies enables the rapid and extensive collection and curation of genetic data for each cancer type into clinical gene expression biobanks. We report the application of bioinformatics tools for investigating the expression patterns and prognostic significance of three genes that are commonly dysregulated in colon cancer: adenomatous polyposis coli (APC); B-Raf proto-oncogene (BRAF); and Kirsten rat sarcoma viral oncogene homologue (KRAS). Through the use of bioinformatics tools, we show the patterns of APC, BRAF and KRAS genetic alterations and their role in patient prognosis. Our results show mutation types, the frequency of mutations, tumour anatomical location and differential expression patterns for APC, BRAF and KRAS for colorectal tumour and matched healthy tissue. The prognostic value of APC, BRAF and KRAS genetic alterations was investigated as a function of their expression levels in CRC. In the era of precision medicine, with significant advancements in biobanking and data curation, there is significant scope to use existing clinical data sets for evaluating the role of mutational drivers in carcinogenesis. This approach offers the potential for studying combinations of less well-known genes and the discovery of novel biomarkers, or for studying the association between various effector proteins and pathways.

Molecular mechanisms underlying the resistance of BRAF V600E-mutant metastatic colorectal cancer to EGFR/BRAF inhibitors

Background

Combinatorial inhibition of epidermal growth factor receptor (EGFR) and BRAF shows remarkable clinical benefits in patients with BRAF V600E-mutant metastatic colorectal cancer (mCRC). However, the tumor may inevitably develop resistance to the targeted therapy, thereby limiting the response rate and durability. This study aimed to determine the genetic alterations associated with intrinsic and acquired resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC.

Methods

Targeted sequencing of 520 cancer-related genes was performed in tumor tissues and in plasma samples collected from patients with BRAF V600E-mutant mCRC, who were treated with EGFR/BRAF ± MEK inhibitors, before and after the targeted treatment. Clinical benefit was defined as an objective response or a stable disease lasting longer than the median progression-free survival (PFS).

Results

In all, 25 patients with BRAF V600E-mutant mCRC were included in this study. Those with RNF43 mutations (n = 8) were more likely to achieve clinical benefit from EGFR/BRAF inhibitors than those with wild-type RNF43 (87.5% versus 37.5%, p = 0.034). Genetic alterations in receptor tyrosine kinase genes (n = 6) were associated with worse PFS (p = 0.005). Among the 23 patients whose disease progressed after the EGFR/BRAF-targeted therapy, at least one acquired resistance-related mutation was detected in 12 patients. Acquired mutations were most frequently observed in the mitogen-activated protein kinase pathway-related genes (n = 9), including KRAS (G12D and Q61H/R), NRAS (Q61L/R/K and amplification), BRAF (amplification), and MEK1 (K57T). MET amplification and PIK3R1 Q579fs mutation emerged in three patients and one patient, respectively, after disease progression.

Conclusion

Multiple genetic alterations are associated with clinical benefits and resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC. Our findings provide novel insights into strategies for overcoming resistance to EGFR/BRAF inhibitors in patients with BRAF V600E-mutant mCRC.

Multi-Omics Prognostic Signatures Based on Lipid Metabolism for Colorectal Cancer

Background: The potential biological processes and laws of the biological components in malignant tumors can be understood more systematically and comprehensively through multi-omics analysis. This study elaborately explored the role of lipid metabolism in the prognosis of colorectal cancer (CRC) from the metabonomics and transcriptomics.

Methods: We performed K-means unsupervised clustering algorithm and t test to identify the differential lipid metabolites determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) in the serum of 236 CRC patients of the First Hospital of Jilin University (JLUFH). Cox regression analysis was used to identify prognosis-associated lipid metabolites and to construct multi-lipid-metabolite prognostic signature. The composite nomogram composed of independent prognostic factors was utilized to individually predict the outcome of CRC patients. Glycerophospholipid metabolism was the most significant enrichment pathway for lipid metabolites in CRC, whose related hub genes (GMRHGs) were distinguished by gene set variation analysis (GSVA) and weighted gene co-expression network analysis (WGCNA). Cox regression and least absolute shrinkage and selection operator (LASSO) regression analysis were utilized to develop the prognostic signature.

Results: Six-lipid-metabolite and five-GMRHG prognostic signatures were developed, indicating favorable survival stratification effects on CRC patients. Using the independent prognostic factors as variables, we established a composite nomogram to individually evaluate the prognosis of CRC patients. The AUCs of one-, three-, and five-year ROC curves were 0.815, 0.815, and 0.805, respectively, showing auspicious prognostic accuracy. Furthermore, we explored the potential relationship between tumor microenvironment (TME) and immune infiltration. Moreover, the mutational frequency of TP53 in the high-risk group was significantly higher than that in the low-risk group (p < 0.001), while in the coordinate mutational status of TP53, the overall survival of CRC patients in the high-risk group was significantly lower than that in low-risk group with statistical differences.

Conclusion: We identified the significance of lipid metabolism for the prognosis of CRC from the aspects of metabonomics and transcriptomics, which can provide a novel perspective for promoting individualized treatment and revealing the potential molecular biological characteristics of CRC. The composite nomogram including a six-lipid-metabolite prognostic signature is a promising predictor of the prognosis of CRC patients.

Prevalence and Spectrum of Predisposition Genes With Germline Mutations Among Chinese Patients With Bowel Cancer

Background: Bowel cancer is the third-most common cancer and the second leading cause of cancer-related death worldwide. Bowel cancer has a substantial hereditary component; however, additional hereditary risk factors involved in bowel cancer pathogenesis have not been systematically defined.

Materials and Methods: A total of 573 patients with bowel cancer were enrolled in the present study, of whom 93.72% had colorectal cancer (CRC). Germline mutations were integrated with somatic mutation information via utilizing target next-generation sequencing.

Results: Pathogenic/Likely Pathogenic (P/LP) germline alterations were identified in 47 (8.2%) patients with bowel cancer and the ratio of the number of these patients with family history was significantly higher in the P/LP group than that noted in the non-pathogenic (Non-P) group. Certain rare germline alterations were noted, such as those noted in the following genes: FANCD2, CDH1, and FLCN. A total of 32 patients (68.1%) had germline alterations in the DNA-damage repair (DDR) genes and homologous recombination (HR) accounted for the highest proportion of this subgroup. By comparing 573 patients with bowel cancer with reference controls (China_MAPs database), significant associations (p < 0.01) were observed between the incidence of bowel cancer and the presence of mutations in APC, ATM, MLH1, FANCD2, MSH3, MSH6, PMS1, and RAD51D. Somatic gene differential analysis revealed a marked difference in 18 genes and a significant difference was also noted in tumor mutation burden (TMB) between germline mutation carriers and non-germline mutation subjects (p < 0.001). In addition, TMB in DDR mutation groups indicated a dramatic difference compared with the non-DDR mutation group (p < 0.01). However, no statistically significant differences in TMB were noted among detailed DDR pathways for patients with bowel cancer, irrespective of the presence of germline mutations. Moreover, a significantly higher level (p < 0.0001) of mutation count was observed in the DDR group from The Cancer Genome Atlas (TCGA) database and the DDR and non-DDR alteration groups displayed various immune profiles.

Conclusion: Chinese patients with bowel cancer exhibited a distinct spectrum of germline variants, with distinct molecular characteristics such as TMB and DDR. Furthermore, the information on somatic mutations obtained from TCGA database indicated that a deeper understanding of the interactions among DDR and immune cells would be useful to further investigate the role of DDR in bowel cancer.

Circular RNA hsa_circ_0000285 regulates the microRNA‐599/G‐protein subunit gamma 12 (miR‐599/GNG12) axis to promote glioma progression

Objective

Glioma is the most common, rapidly progressing, lethal brain tumor. However, underlying mechanisms behind its abnormal progression remain largely unknown. This study aimed to investigate mechanism of action and effects of the hsa_circ_0000285 on glioma progression.

Methods

RT‐qPCR was utilized to study RNA expression in glioma tissues and cell lines. The effects of hsa_circ_0000285 on glioma progression were studied by measuring cell proliferation and migration, apoptosis, tumor volume and weight in both glioma cells and xenograft glioma mice. The features of hsa_circ_0000285 were identified using chromatin fractionation and RNase digestion. Its mechanism of action was analyzed using bioinformatics, RNA‐binding protein immunoprecipitation, and luciferase reporter assay.

Results

We found glioma tissues and cell lines were overexpressing hsa_circ_0000285. While hsa_circ_0000285 promoted cell proliferation and migration, it inhibited apoptosis in vitro. It also increased tumor volume and weight in vivo. Using bioinformatic analysis and verification experiments for studying its mechanisms, we confirmed that hsa_circ_0000285 sponged miR‐599, which negatively regulated GNG12 by binding to its mRNA.

Conclusion

Hsa_circ_0000285 is overexpressed in the glioma and promotes its progression by directly regulating the miR‐599/GNG12 axis. This novel mechanism, therefore, shows that the hsa_circ_0000285/miR‐599/GNG12 axis may be a promising therapeutic target for glioma treatment.

Wnt/β-catenin signalling: function, biological mechanisms, and therapeutic opportunities

The Wnt/β-catenin pathway comprises a family of proteins that play critical roles in embryonic development and adult tissue homeostasis. The deregulation of Wnt/β-catenin signalling often leads to various serious diseases, including cancer and non-cancer diseases. Although many articles have reviewed Wnt/β-catenin from various aspects, a systematic review encompassing the origin, composition, function, and clinical trials of the Wnt/β-catenin signalling pathway in tumour and diseases is lacking. In this article, we comprehensively review the Wnt/β-catenin pathway from the above five aspects in combination with the latest research. Finally, we propose challenges and opportunities for the development of small-molecular compounds targeting the Wnt signalling pathway in disease treatment.

Prognostic Factors of Colorectal Cancer: A Comparative Study on Patients With or Without Liver Metastasis

Background

Radical or palliative surgery with subsequent adjuvant therapy is the routine treatment for stage II/III colorectal cancer(CRC) and some stage IV CRC patients. This study aimed to clarify the prognostic clinicopathological and genetic factors for these patients.

Methods

Fifty-five stage II-IV CRC patients undergoing surgery and adjuvant therapy were recruited, including patients without liver metastasis(5 at stage II, 21 at stage III) and with liver metastasis(29 at stage IV). Genetic alterations of the primary cancer tissues were investigated by whole exome sequencing(WES). Patients were followed up to 1652 days(median at 788 days).

Results

The mutational landscape of primary CRC tissue of patients with or without liver metastasis was largely similar, although the mutational frequency of TRIM77 and TCF7L2 was significantly higher in patients with liver metastasis. Several main driver gene co-mutations, such as TP53-APC, APC-KRAS, APC-FRG1, and exclusive mutations, such as TP53-CREBBP, were found in patients with liver metastasis, but not in patients without liver metastasis. No significant difference was found between the two groups in aberrant pathways. If stage II-IV patients were studied altogether, relapse status, SUPT20HL1 mutations, Amp27_21q22.3 and Del8_10q23.2 were independent risk factors(P<0.05). If patients were divided into two groups by metastatic status, surgery types and Amp6_20q13.33 were independent risk factors for patients without liver metastasis(P<0.05), while TRIM77 mutations were the only independent risk factor for patients with liver metastasis(P<0.05).

Conclusions

Surgery types and Amp6_20q13.33 were independent risk factors for CRC patients without liver metastasis, and TRIM77 mutations were the independent risk factor for CRC patients with liver metastasis.

Molecular drivers of tumor progression in microsatellite stable APC mutation-negative colorectal cancers

The tumor suppressor gene adenomatous polyposis coli (APC) is the initiating mutation in approximately 80% of all colorectal cancers (CRC), underscoring the importance of aberrant regulation of intracellular WNT signaling in CRC development. Recent studies have found that early-onset CRC exhibits an increased proportion of tumors lacking an APC mutation. We set out to identify mechanisms underlying APC mutation-negative (APC^mut-) CRCs. We analyzed data from The Cancer Genome Atlas to compare clinical phenotypes, somatic mutations, copy number variations, gene fusions, RNA expression, and DNA methylation profiles between APC^mut- and APC mutation-positive (APC^mut+) microsatellite stable CRCs. Transcriptionally, APC^mut- CRCs clustered into two approximately equal groups. Cluster One was associated with enhanced mitochondrial activation. Cluster Two was strikingly associated with genetic inactivation or decreased RNA expression of the WNT antagonist RNF43, increased expression of the WNT agonist RSPO3, activating mutation of BRAF, or increased methylation and decreased expression of AXIN2. APC^mut- CRCs exhibited evidence of increased immune cell infiltration, with significant correlation between M2 macrophages and RSPO3. APC^mut- CRCs comprise two groups of tumors characterized by enhanced mitochondrial activation or increased sensitivity to extracellular WNT, suggesting that they could be respectively susceptible to inhibition of these pathways.

The Wnt signaling pathway in tumorigenesis, pharmacological targets, and drug development for cancer therapy

Wnt signaling was initially recognized to be vital for tissue development and homeostasis maintenance. Further studies revealed that this pathway is also important for tumorigenesis and progression. Abnormal expression of signaling components through gene mutation or epigenetic regulation is closely associated with tumor progression and poor prognosis in several tissues. Additionally, Wnt signaling also influences the tumor microenvironment and immune response. Some strategies and drugs have been proposed to target this pathway, such as blocking receptors/ligands, targeting intracellular molecules, beta-catenin/TCF4 complex and its downstream target genes, or tumor microenvironment and immune response. Here we discuss the roles of these components in Wnt signaling pathway in tumorigenesis and cancer progression, the underlying mechanisms that is responsible for the activation of Wnt signaling, and a series of drugs targeting the Wnt pathway provide multiple therapeutic values. Although some of these drugs exhibit exciting anti-cancer effect, clinical trials and systematic evaluation should be strictly performed along with multiple-omics technology.

Oncogenic BRAF, unrestrained by TGFβ-receptor signalling, drives right-sided colonic tumorigenesis

Right-sided (proximal) colorectal cancer (CRC) has a poor prognosis and a distinct mutational profile, characterized by oncogenic BRAF mutations and aberrations in mismatch repair and TGFβ signalling. Here, we describe a mouse model of right-sided colon cancer driven by oncogenic BRAF and loss of epithelial TGFβ-receptor signalling. The proximal colonic tumours that develop in this model exhibit a foetal-like progenitor phenotype (Ly6a/Sca1⁺) and, importantly, lack expression of Lgr5 and its associated intestinal stem cell signature. These features are recapitulated in human BRAF-mutant, right-sided CRCs and represent fundamental differences between left- and right-sided disease. Microbial-driven inflammation supports the initiation and progression of these tumours with foetal-like characteristics, consistent with their predilection for the microbe-rich right colon and their antibiotic sensitivity. While MAPK-pathway activating mutations drive this foetal-like signature via ERK-dependent activation of the transcriptional coactivator YAP, the same foetal-like transcriptional programs are also initiated by inflammation in a MAPK-independent manner. Importantly, in both contexts, epithelial TGFβ-receptor signalling is instrumental in suppressing the tumorigenic potential of these foetal-like progenitor cells.

Oncogenic BRAF, unrestrained by TGFβ-receptor signalling, drives right-sided colonic tumorigenesis

Right-sided (proximal) colorectal cancer (CRC) has a poor prognosis and a distinct mutational profile, characterized by oncogenic BRAF mutations and aberrations in mismatch repair and TGFβ signalling. Here, we describe a mouse model of right-sided colon cancer driven by oncogenic BRAF and loss of epithelial TGFβ-receptor signalling. The proximal colonic tumours that develop in this model exhibit a foetal-like progenitor phenotype (Ly6a/Sca1+) and, importantly, lack expression of Lgr5 and its associated intestinal stem cell signature. These features are recapitulated in human BRAF-mutant, right-sided CRCs and represent fundamental differences between left- and right-sided disease. Microbial-driven inflammation supports the initiation and progression of these tumours with foetal-like characteristics, consistent with their predilection for the microbe-rich right colon and their antibiotic sensitivity. While MAPK-pathway activating mutations drive this foetal-like signature via ERK-dependent activation of the transcriptional coactivator YAP, the same foetal-like transcriptional programs are also initiated by inflammation in a MAPK-independent manner. Importantly, in both contexts, epithelial TGFβ-receptor signalling is instrumental in suppressing the tumorigenic potential of these foetal-like progenitor cells.

Multiple Endocrine Neoplasia Type 1: Latest Insights

Multiple endocrine neoplasia type 1 (MEN1), a rare tumor syndrome that is inherited in an autosomal dominant pattern, is continuing to raise great interest for endocrinology, gastroenterology, surgery, radiology, genetics, and molecular biology specialists. There have been 2 major clinical practice guidance papers published in the past 2 decades, with the most recent published 8 years ago. Since then, several new insights on the basic biology and clinical features of MEN1 have appeared in the literature, and those data are discussed in this review. The genetic and molecular interactions of the MEN1-encoded protein menin with transcription factors and chromatin-modifying proteins in cell signaling pathways mediated by transforming growth factor β/bone morphogenetic protein, a few nuclear receptors, Wnt/β-catenin, and Hedgehog, and preclinical studies in mouse models have facilitated the understanding of the pathogenesis of MEN1-associated tumors and potential pharmacological interventions. The advancements in genetic diagnosis have offered a chance to recognize MEN1-related conditions in germline MEN1 mutation-negative patients. There is rapidly accumulating knowledge about clinical presentation in children, adolescents, and pregnancy that is translatable into the management of these very fragile patients. The discoveries about the genetic and molecular signatures of sporadic neuroendocrine tumors support the development of clinical trials with novel targeted therapies, along with advancements in diagnostic tools and surgical approaches. Finally, quality of life studies in patients affected by MEN1 and related conditions represent an effort necessary to develop a pharmacoeconomic interpretation of the problem. Because advances are being made both broadly and in focused areas, this timely review presents and discusses those studies collectively.

BRAFV600E drives dedifferentiation in small intestinal and colonic organoids and cooperates with mutant p53 and Apc loss in transformation

BRAF^V600E confers poor prognosis and is associated with a distinct subtype of colorectal cancer (CRC). Little is known, however, about the genetic events driving the initiation and progression of BRAF^V600E mutant CRCs. Recent genetic analyses of CRCs indicate that BRAF^V600E often coexists with alterations in the WNT- and p53 pathways, but their cooperation remains ill-defined. Therefore, we systematically compared small and large intestinal organoids from mice harboring conditional Braf^floxV600E, Trp53^LSL-R172H, and/or Apc^flox/flox alleles. Using these isogenic models, we observe tissue-specific differences toward sudden BRAF^V600E expression, which can be attributed to different ERK-pathway ground states in small and large intestinal crypts. BRAF^V600E alone causes transient proliferation and suppresses epithelial organization, followed by organoid disintegration. Moreover, BRAF^V600E induces a fetal-like dedifferentiation transcriptional program in colonic organoids, which resembles human BRAF^V600E-driven CRC. Co-expression of p53^R172H delays organoid disintegration, confers anchorage-independent growth, and induces invasive properties. Interestingly, p53^R172H cooperates with BRAF^V600E to modulate the abundance of transcripts linked to carcinogenesis, in particular within colonic organoids. Remarkably, WNT-pathway activation by Apc deletion fully protects organoids against BRAF^V600E-induced disintegration and confers growth/niche factor independence. Still, Apc-deficient BRAF^V600E-mutant organoids remain sensitive toward the MEK inhibitor trametinib, albeit p53^R172H confers partial resistance against this clinically relevant compound. In summary, our systematic comparison of the response of small and large intestinal organoids to oncogenic alterations suggests colonic organoids to be better suited to model the human situation. In addition, our work on BRAF-, p53-, and WNT-pathway mutations provides new insights into their cooperation and for the design of targeted therapies.