Implications for KRAS status and EGFR-targeted therapies in metastatic CRC

Photoimmunotherapy for cancer treatment based on organic small molecules: Recent strategies and future directions

Photodynamic therapy (PDT) is considered as a promising anticancer approach, owning to its high efficiency and spatiotemporal selectivity. Ample evidence indicated that PDT can trigger immunogenic cell death by releasing antigens that activate immune cells to promote anti-tumor immunity. Nevertheless, the inherent nature of tumors and their complex heterogeneity often limits the efficiency of PDT, which can be overcome with a novel strategy of photo-immunotherapy (PIT) strategy. By exploring the principles of PDT induction and ICD enhancement, combined with other therapies such as chemotherapy or immune checkpoint blockade, the tailored solutions can be designed to address specific challenges of drug resistance, hypoxic conditions, and tumor immunosuppressive microenvironments (TIMEs), which enables targeted enhancement of systemic immunity to address most distant and recurrent cancers. The present article summarizes the specific strategies of PIT and discusses recent existing limitations. More importantly, we anticipate that the perspectives presented herein will help address the clinical translation challenges associated with PIT.

Prognostic implications, genomic and immune characteristics of lung adenocarcinoma with lepidic growth pattern

AIMS

Conflicting data were provided regarding the prognostic impact and genomic features of lung adenocarcinoma (LUAD) with lepidic growth pattern (LP+A). Delineation of the genomic and immune characteristics of LP+A could provide deeper insights into its prognostic implications and treatment determination.

METHODS

We conducted a search of articles in PubMed, EMBASE and the Cochrane Library from inception to January 2024. A domestic cohort consisting of 52 LUAD samples was subjected to whole-exome sequencing as internal validation. Data from The Cancer Genomic Atlas and the Gene Expression Omnibus datasets were obtained to characterise the genomic and immune profiles of LP+A. Pooled HRs and rates were calculated.

RESULTS

The pooled results indicated that lepidic growth pattern was either predominant (0.35, 95% CI 0.22 to 0.56, p<0.01) or minor (HR 0.50, 95% CI 0.36 to 0.70, p<0.01) histological subtype was associated with favourable disease-free survival. Pooled gene mutation rates suggested higher EGFR mutation (0.55, 95% CI 0.46 to 0.64, p<0.01) and lower KRAS mutation (0.14, 95% CI 0.02 to 0.25, p=0.02) in lepidic-predominant LUAD. Lepidic-predominant LUAD had lower tumour mutation burden and pooled positive rate of PD-L1 expression compared with other subtypes. LP+A was characterised by abundance in resting CD4+memory T cells, monocytes and γδ T cells, as well as scarcity of cancer-associated fibroblasts.

CONCLUSIONS

LP+A was a unique histological subtype with a higher EGFR mutation rate, lower tumour mutation burden and immune checkpoint expression levels. Our findings suggested potential benefits from targeted therapy over immunotherapy in LP+A.

Targeting the EGFR signalling pathway in metastatic colorectal cancer

Epidermal growth factor receptor (EGFR) and its activated downstream signalling pathways play a crucial role in colorectal cancer development and progression. After four decades of preclinical, translational, and clinical research, it has been shown that blocking the EGFR signalling pathway at different molecular levels represents a fundamental therapeutic strategy for patients with metastatic colorectal cancer. Nevertheless, the efficacy of molecularly targeted therapies is inescapably limited by the insurgence of mechanisms of acquired cancer cell resistance. Thus, in the era of precision medicine, a deeper understanding of the complex molecular landscape of metastatic colorectal cancer is required to deliver the best treatment choices to all patients. Major efforts are currently ongoing to improve patient selection, improve the efficacy of available treatments targeting the EGFR pathway, and develop novel combination strategies to overcome therapy resistance within the continuum of care of metastatic colorectal cancer.

Emerging Trends in Gastrointestinal Cancer Targeted Therapies: Harnessing Tumor Microenvironment, Immune Factors, and Metabolomics Insights

Gastrointestinal (GI) cancers are the leading cause of new cancer cases and cancer-related deaths worldwide. The treatment strategies for patients with GI tumors have focused on oncogenic molecular profiles associated with tumor cells. Recent evidence has demonstrated that the tumor cell functions are modulated by its microenvironment, compromising fibroblasts, extracellular matrices, microbiome, immune cells, and the enteric nervous system. Along with the tumor microenvironment components, alterations in key metabolic pathways have emerged as a hallmark of tumor cells. From these perspectives, this review will highlight the functions of different cellular components of the GI tumor microenvironment and their implications for treatment. Furthermore, we discuss the major metabolic reprogramming in GI tumor cells and how understanding metabolic rewiring could lead to new therapeutic strategies. Finally, we briefly summarize the targeted agents currently being studied in GI cancers. Understanding the complex interplay between tumor cell-intrinsic and -extrinsic factors during tumor progression is critical for developing new therapeutic strategies.

Transglutaminase 2 serves as a pathogenic hub gene of KRAS mutant colon cancer based on integrated analysis

BACKGROUND

Colon cancer is acknowledged as one of the most common malignancies worldwide, ranking third in United States regarding incidence and mortality. Notably, approximately 40% of colon cancer cases harbor oncogenic KRAS mutations, resulting in the continuous activation of epidermal growth factor receptor signaling.

AIM

To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.

METHODS

Weighted gene co-expression network analysis, in combination with additional bioinformatics analysis, were conducted to screen the key factors driving the progression of KRAS mutant colon cancer. Meanwhile, various in vitro experiments were also conducted to explore the biological function of transglutaminase 2 (TGM2).

RESULTS

Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival. Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer. Additionally, biological roles of the key gene TGM2 was also assessed, suggesting that the downregulation of TGM2 attenuated the proliferation, invasion, and migration of the KRAS mutant colon cancer cell line.

CONCLUSION

This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer. This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.

The study of primary and acquired resistance to first-line osimertinib to improve the outcome of EGFR-mutated advanced Non-small cell lung cancer patients: the challenge is open for new therapeutic strategies

The development of targeted therapy in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) patients has radically changed their clinical perspectives. Current first-line standard treatment for advanced disease is commonly considered third-generation tyrosine kinase inhibitors (TKI), osimertinib. The study of primary and acquired resistance to front-line osimertinib is one of the main burning issues to further improve patients' outcome. Great heterogeneity has been depicted in terms of duration of clinical benefit and pattern of progression and this might be related to molecular factors including subtypes of EGFR mutations and concomitant genetic alterations. Acquired resistance can be categorized into two main classes: EGFR-dependent and EGFR-independent mechanisms and specific pattern of progression to first-line osimertinib have been demonstrated. The purpose of the manuscript is to provide a comprehensive overview of literature about molecular resistance mechanisms to first-line osimertinib, from a clinical perspective and therefore in relationship to emerging therapeutic approaches.

Exploring the multifaceted role of RASGRP1 in disease: immune, neural, metabolic, and oncogenic perspectives

RAS guanyl releasing protein 1 (RASGRP1) is a guanine nucleotide exchange factor (GEF) characterized by the presence of a RAS superfamily GEF domain. It functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor, specifically activating RAS through the exchange of bound GDP for GTP. Activation of RAS by RASGRP1 has a wide range of downstream effects at the cellular level. Thus, it is not surprising that many diseases are associated with RASGRP1 disorders. Here, we present an overview of the structure and function of RASGRP1, its crucial role in the development, expression, and regulation of immune cells, and its involvement in various signaling pathways. This review comprehensively explores the relationship between RASGRP1 and various diseases, elucidates the underlying molecular mechanisms of RASGRP1 in each disease, and identifies potential therapeutic targets. This study provides novel insights into the role of RASGRP1 in insulin secretion and highlights its potential as a therapeutic target for diabetes. The limitations and challenges associated with studying RASGRP1 in disease are also discussed.

Longitudinal plasma proteome profiling reveals the diversity of biomarkers for diagnosis and cetuximab therapy response of colorectal cancer

Cetuximab therapy is the major treatment for colorectal cancer (CRC), but drug resistance limits its effectiveness. Here, we perform longitudinal and deep proteomic profiling of 641 plasma samples originated from 147 CRC patients (CRCs) undergoing cetuximab therapy with multi-course treatment, and 90 healthy controls (HCs). COL12A1, THBS2, S100A8, and S100A9 are screened as potential proteins to distinguish CRCs from HCs both in plasma and tissue validation cohorts. We identify the potential biomarkers (RRAS2, MMP8, FBLN1, RPTOR, and IMPDH2) for the initial response prediction. In a longitudinal setting, we identify two clusters with distinct fluctuations and construct the model with high accuracy to predict the longitudinal response, further validated in the independent cohort. This study reveals the heterogeneity of different biomarkers for tumor diagnosis, the initial and longitudinal response prediction respectively in the first course and multi-course cetuximab treatment, may ultimately be useful in monitoring and intervention strategies for CRC.

A Challenging Correlation between Tumor Cellularity and Somatic Variant Allele Fraction in Lung and Colorectal Cancers-Specimens of Low Tumor Percentage Should Be Analyzed with Caution

Background and aims: The percentage of tumor cells (tumor cellularity) in a cancerous tissue has been assumed to correlate with the variant allele fraction (VAF) of an identified pathogenic variant. Many laboratories use the tumor cellularity as part of a quality criteria for specimen processing and clinical reporting. However, a systematic study of such correlation has yet to be shown. We performed a relatively large-scale study to determine whether pathologist-estimated tumor cellularity is correlated with next-generation sequencing (NGS)-derived VAF. Materials and Methods: A total of 1511 non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) specimens, including formalin-fixed paraffin-embedded (FFPE) and fine needle aspirated (FNA) tissues, were analyzed by cancer hotspot NGS. For a given specimen, pathogenic variants of BRAF, EGFR, KRAS, and NRAS were identified and the determined VAFs were correlated with the corresponding tissue tumor cellularity. Results: The coefficient of determination R-squared (R2) values were calculated for each correlation. All R2 values were lower than 0.25, indicating poor correlations. Pathogenic variants were found, not uncommonly, in tumor specimens that carried 10% or lower tumor cellularity. There were no apparent differences of R2 values between the FFPE and FNA specimens. Conclusion: In both NSCLC and CRC, the lack of linear relationship between tumor cellularity and VAF was found across a wide range of tumor cell percentages. Caution should be used when using tumor cellularity to triage specimens for NGS testing. The tumor cellularity should be considered in relation to the limit of detection of the specific assay for the proper interpretation of a negative test result.

Targeted Nanoparticles: the Smart Way for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a widespread cancer that starts in the digestive tract. It is the third most common cause of cancer deaths around the world. The World Health Organization (WHO) estimates an expected death toll of over 1 million cases annually. The limited therapeutic options as well as the drawbacks of the existing therapies necessitate the development of non-classic treatment approaches. Nanotechnology has led the evolution of valuable drug delivery systems thanks to their ability to control drug release and precisely target a wide variety of cancers. This has also been extended to the treatment of CRC. Herein, we shed light on the pertinent research that has been performed on the potential applications of nanoparticles in the treatment of CRC. The various types of nanoparticles in addition to their properties, applications, targeting approaches, merits, and demerits are discussed. Furthermore, innovative therapies for CRC, including gene therapies and immunotherapies, are also highlighted. Eventually, the research gaps, the clinical potential of such delivery systems, and a future outlook on their development are inspired.

Synergistic Approach of Antibody-Photosensitizer Conjugate Independent of KRAS-Mutation and Its Downstream Blockade Pathway in Colorectal Cancer

Here, a novel approach is presented to improve the efficacy of antibody-drug conjugates (ADC) by integrating antibody-mediated immunotherapy and photodynamic therapy (PDT) in a combination therapy system utilizing an antibody-photosensitizer conjugate (APC) platform based on a poloxamer polymer linker. To specifically target Kirsten rat sarcoma 2 viral oncogene homolog (KRAS)-mutated cancer cells, an antibody antiepidermal growth factor receptor (EGFR), cetuximab, with a poloxamer linker coupled with the photosensitizer chlorin e6 through click chemistry (cetuximab-maleimide-poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)-chlorine e6 conjugate, CMPXC) is synthesized. CMPXC is cytotoxic upon laser treatment, achieving a 90% cell death by suppressing KRAS downstream signaling pathways associated with ERK and AKT proteins, confirmed using RNA sequencing analysis. In KRAS-mutated colorectal cancer mouse models, CMPXC significantly enhances antitumor efficacy compared with cetuximab treatment alone, resulting in an 86% reduction in tumor growth. Furthermore, CMPXC treatment leads to a 2.24- and 1.75-fold increase in dendritic and priming cytotoxic T cells, respectively, highlighting the immune-activating potential of this approach. The findings suggest that the APC platform addresses the challenges associated with ADC development and EGFR-targeted therapy, including the synergistic advantages of antibody-mediated immunotherapy and PDT.

YB-1 activating cascades as potential targets in KRAS-mutated tumors

Y‑box binding protein‑1 (YB-1) is a multifunctional protein that is highly expressed in human solid tumors of various entities. Several cellular processes, e.g. cell cycle progression, cancer stemness and DNA damage signaling that are involved in the response to chemoradiotherapy (CRT) are tightly governed by YB‑1. KRAS gene with about 30% mutations in all cancers, is considered the most commonly mutated oncogene in human cancers. Accumulating evidence indicates that oncogenic KRAS mediates CRT resistance. AKT and p90 ribosomal S6 kinase are downstream of KRAS and are the major kinases that stimulate YB‑1 phosphorylation. Thus, there is a close link between the KRAS mutation status and YB‑1 activity. In this review paper, we highlight the importance of the KRAS/YB‑1 cascade in the response of KRAS-mutated solid tumors to CRT. Likewise, the opportunities to interfere with this pathway to improve CRT outcome are discussed in light of the current literature.

Prevalence of KRAS G12C Mutation and Co-mutations and Associated Clinical Outcomes in Patients With Colorectal Cancer: A Systematic Literature Review

PURPOSE

A systematic literature review was conducted to estimate the global prevalence of Kirsten rat sarcoma virus gene (KRAS) mutations, with an emphasis on the clinically significant KRAS G12C mutation, and to estimate the prognostic significance of these mutations in patients with colorectal cancer (CRC).

DESIGN

Relevant English-language publications in the Embase, MEDLINE, and the Cochrane Library databases (from 2009 to 2021) and congress presentations (from 2016 to 2021) were reviewed. Eligible studies were those that reported the prevalence and clinical outcomes of the KRAS G12C mutation in patients with CRC.

RESULTS

A total of 137 studies (interventional [n = 8], post hoc analyses of randomized clinical trials [n = 6], observational [n = 122], and longitudinal [n =1]) were reviewed. Sixty-eight studies reported the prevalence of KRAS mutations (KRASm) in 42 810 patients with CRC. The median global prevalence of KRASm was 38% (range, 13.3%-58.9%) and that of the KRAS G12C mutation (KRAS G12C) 3.1% (range, 0.7%-14%). Available evidence suggests that KRASm are possibly more common in tumors that develop on the right side of the colon. Limited evidence suggests a lower objective response rate and inferior disease-free/relapse-free survival in patients with KRAS G12C compared with patients with KRASwt or other KRASm.

CONCLUSION

Our analysis reveals that KRAS G12C is prevalent in 3% of patients with CRC. Available evidence suggests a poor prognosis for patients with KRAS G12C. Right-sided tumors were more likely to harbor KRASm; however, their role in determining clinical outcomes needs to be investigated further.

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.

Effect of BRAF mutation on the prognosis for patients with colorectal cancer undergoing cytoreductive surgery for synchronous peritoneal metastasis

Background

KRAS/BRAF mutations (mutKRAS/mutBRAF) are unfavorable prognostic factors for colorectal cancer (CRC) metastases to the liver and lungs. However, their effects on the prognosis for patients with synchronous peritoneal metastasis (S-PM) of CRC after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are controversial. In the study, we aimed to determine the effects of mutKRAS/mutBRAF on the prognosis for patients with S-PM who received CRS.

Methods

A total of 142 patients diagnosed with S-PM between July 2007 and July 2019 were included in this study. The demographics, mutKRAS/mutBRAF status, overall survival (OS), and progression-free survival (PFS) of the patients were evaluated. The Kaplan-Meier method and log-rank test were used to estimate the difference in survival between groups.

Results

Among 142 patients, 68 (47.9%) showed mutKRAS and 42 (29.5%) showed mutBRAF. The median OS values were 8.4 and 34.3 months for patients with mutBRAF and BRAF wild-type, respectively (P < 0.01). However, KRAS status was not significantly associated with median OS (P = 0.76). Multivariate analysis revealed carcinoembryonic antigen, CRS, HIPEC, and mutBRAF as independent predictors for OS. Based on these findings, a nomogram was constructed. The C-index was 0.789 (95% confidence interval, 0.742-0.836), indicating good predictive ability of the model. Furthermore, the 1- and 2-year survival calibration plots showed good agreement between the predicted and actual OS rates. The area under curves of the 1- and 2-year survival predictions based on the nomogram were 0.807 and 0.682, respectively. Additionally, mutBRAF was significantly associated with lower PFS (P < 0.001).

Conclusions

mutBRAF is an independent prognostic risk factor for S-PM. The established nomogram predicted the OS of patients with CRC having S-PM with high accuracy, indicating its usefulness as a valuable prognostic tool for the designated patient cohort.

Molecular targeted therapy for metastatic colorectal cancer: current and evolving approaches

Colorectal cancer (CRC) represents 10% of all cancer types, making it the third leading cause of cancer-related deaths globally. Metastasis is the primary factor causing mortality in CRC patients. Approximately 22% of CRC-related deaths have metastasis present at diagnosis, with approximately 70% of these cases recurring. Recently, with the application of novel targeted drugs, targeted therapy has become the first-line option for individualized and comprehensive treatment of CRC. The management of these patients remains a significant medical challenge. The most prevalent targeted therapies for CRC in clinical practice focus on anti-vascular endothelial growth factor and its receptor, epidermal growth factor receptor (EGFR), and multi-target kinase inhibitors. In the wake of advancements in precision diagnosis and widespread adoption of second-generation sequencing (NGS) technology, rare targets such as BRAF V600E mutation, KRAS mutation, HER2 overexpression/amplification, and MSI-H/dMMR in metastatic colorectal cancer (mCRC) are increasingly being discovered. Simultaneously, new therapeutic drugs targeting these mutations are being actively investigated. This article reviews the progress in clinical research for developing targeted therapeutics for CRC, in light of advances in precision medicine and discovery of new molecular target drugs.

Novel heavily fucosylated glycans as a promising therapeutic target in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is highly prevalent and lethal globally, and its prognosis remains unsatisfactory. Drug resistance is regarded as the main cause of treatment failure leading to tumor recurrence and metastasis. The overexpression of fucosylated epitopes, which are usually modifications of glycoproteins, was reported to occur in various epithelial cancers. However, the effects of treatments that target these antigens in colorectal cancer remain unclear.

METHODS

This study investigated the expression of heavily fucosylated glycans (HFGs) in 30 clinical samples from patients with CRC and other normal human tissues. The complement-dependent cytotoxicity was explored in vitro through treatment with anti-HFG monoclonal antibody (mAb) alone or in combination with chemotherapeutic agents. In vivo inhibitory effects were also examined using a xenograft mouse model.

RESULTS

Immunohistochemistry staining and western blotting revealed that HFG expression was higher in human colorectal cancer tissues than in normal tissues. In DLD-1 and SW1116 cells, which overexpress fucosylated epitopes, anti-HFG mAb produced observable cytotoxic effects, especially when it was combined with chemotherapeutic agents. The xenograft model also demonstrated that anti-HFG mAb had potent and dose-dependent inhibitory effects on colorectal tumor growth.

CONCLUSIONS

As a novel cancer antigen, HFGs are a promising treatment target, and the implementation of anti-HFG mAb treatment for CRC warrants further investigation.

2,3,5,4'-Tetrahydroxystilbene (TG1), a Novel Compound Derived from 2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-glucoside (THSG), Inhibits Colorectal Cancer Progression by Inducing Ferroptosis, Apoptosis, and Autophagy

BACKGROUND

Colorectal cancer (CRC) is one of the deadliest cancers worldwide and long-term survival is not guaranteed in metastatic disease despite current multidisciplinary therapies. A new compound 2,3,5,4'-Tetrahydroxystilbene (TG1), derived from THSG (2,3,5,4'-Tetrahydroxystilbene-2-O-β-D-Glucoside), has been developed, and its anticancer ability against CRC is verified in this study.

METHODS

HCT116, HT-29, and DLD-1 were treated with TG1 and the IC₅₀ was measured using a sulforhodamine B assay. A Xenograft mouse model was used to monitor tumor growth. Apoptosis and autophagy, induced by TG1 in CRC cells, were examined. RNA-sequencing analysis of CRC cells treated with TG1 was performed to discover underlying pathways and mechanisms.

RESULTS

The results demonstrated that treatment with TG1 inhibited CRC proliferation in vitro and in vivo and induced apoptotic cell death, which was confirmed by Annexin V-FITC/PI staining and Western blotting. Additionally, TG1 treatment increased the level of autophagy in cells. RNA-sequencing and GSEA analyses revealed that TG1 was associated with MYC and the induction of ferroptosis. Furthermore, the ferroptosis inhibitor Bardoxolone abrogated the cytotoxic effect of TG1 in CRC cells, indicating that ferroptosis played a crucial role in TG1-induced cytotoxicity.

CONCLUSIONS

These findings suggest that TG1 might be a potential and potent compound for clinical use in the treatment of CRC by inhibiting proliferation and inducing ferroptosis through the MYC pathway.

Negative correlation between acetyl-CoA acyltransferase 2 and cetuximab resistance in colorectal cancer

The emergence of anti-EGFR therapy has revolutionized the treatment of colorectal cancer (CRC). However, not all patients respond consistently well. Therefore, it is imperative to conduct further research to identify the molecular mechanisms underlying the development of cetuximab resistance in CRC. In this study, we find that the expressions of many metabolism-related genes are downregulated in cetuximab-resistant CRC cells compared to their sensitive counterparts. Specifically, acetyl-CoA acyltransferase 2 (ACAA2), a key enzyme in fatty acid metabolism, is downregulated during the development of cetuximab resistance. Silencing of ACAA2 promotes proliferation and increases cetuximab tolerance in CRC cells, while overexpression of ACAA2 exerts the opposite effect. RTK-Kras signaling might contribute to the downregulation of ACAA2 expression in CRC, and ACAA2 predicts CRC prognosis in patients with Kras mutations. Collectively, our data suggest that modulating ACAA2 expression contributes to secondary cetuximab resistance in Kras wild-type CRC patients. ACAA2 expression is related to Kras mutation and demonstrates a prognostic role in CRC patients with Kras mutation. Thus, ACAA2 is a potential target in CRC with Kras mutation.

Bayesian estimation of two-part joint models for a longitudinal semicontinuous biomarker and a terminal event with INLA: Interests for cancer clinical trial evaluation

Two-part joint models for a longitudinal semicontinuous biomarker and a terminal event have been recently introduced based on frequentist estimation. The biomarker distribution is decomposed into a probability of positive value and the expected value among positive values. Shared random effects can represent the association structure between the biomarker and the terminal event. The computational burden increases compared to standard joint models with a single regression model for the biomarker. In this context, the frequentist estimation implemented in the R package frailtypack can be challenging for complex models (i.e., a large number of parameters and dimension of the random effects). As an alternative, we propose a Bayesian estimation of two-part joint models based on the Integrated Nested Laplace Approximation (INLA) algorithm to alleviate the computational burden and fit more complex models. Our simulation studies confirm that INLA provides accurate approximation of posterior estimates and to reduced computation time and variability of estimates compared to frailtypack in the situations considered. We contrast the Bayesian and frequentist approaches in the analysis of two randomized cancer clinical trials (GERCOR and PRIME studies), where INLA has a reduced variability for the association between the biomarker and the risk of event. Moreover, the Bayesian approach was able to characterize subgroups of patients associated with different responses to treatment in the PRIME study. Our study suggests that the Bayesian approach using the INLA algorithm enables to fit complex joint models that might be of interest in a wide range of clinical applications.

A Novel EGFR Targeted Immunotoxin Based on Cetuximab and Type 1 RIP Quinoin Overcomes the Cetuximab Resistance in Colorectal Cancer Cells

Cetuximab is a monoclonal antibody blocking the epidermal growth factor receptor (EGFR) in metastatic colorectal cancer (mCRC). However, cetuximab treatment has no clinical benefits in patients affected by mCRC with KRAS mutation or in the presence of constitutive activation of signalling pathways acting downstream of the EGFR. The aim of this study was to improve cetuximab's therapeutic action by conjugating cetuximab with the type 1 ribosome inactivating protein (RIP) quinoin isolated from quinoa seeds. A chemical conjugation strategy based on the use of heterobifunctional reagent succinimidyl 3-(2-pyridyldithio)propionate (SPDP) was applied to obtain the antibody-type 1 RIP chimeric immunoconjugate. The immunotoxin was then purified by chromatographic technique, and its enzymatic action was evaluated compared to quinoin alone. Functional assays were performed to test the cytotoxic action of the quinoin cetuximab immunoconjugate against the cetuximab-resistant GEO-CR cells. The novel quinoin cetuximab immunoconjugate showed a significant dose-dependent cytotoxicity towards GEO-CR cells, achieving IC50 values of 27.7 nM (~5.0 μg/mL) at 72 h compared to cetuximab (IC50 = 176.7 nM) or quinoin (IC50 = 149.3 nM) alone assayed in equimolar amounts. These results support the therapeutic potential of quinoin cetuximab immunoconjugate for the EGFR targeted therapy, providing a promising candidate for further development towards clinical use in the treatment of cetuximab-resistant metastatic colorectal cancer.

CD46 protects the bladder cancer cells from cetuximab-mediated cytotoxicity

Epidermal growth factor receptor (EGFR) is an effective target for those patients with metastatic colorectal cancers that retain the wild-type RAS gene. However, its efficacy in many cancers, including bladder cancer, is unclear. Here, we studied the in vitro effects of cetuximab monoclonal antibodies (mAbs) targeting EGFR on the bladder cancer cells and role of CD46. Cetuximab was found to inhibit the growth of both colon and bladder cancer cell lines. Furthermore, cetuximab treatment inhibited AKT and ERK phosphorylation in the bladder cancer cells and reduced the expression of CD46 membrane-bound proteins. Restoration of CD46 expression protected the bladder cancer cells from cetuximab-mediated inhibition of AKT and ERK phosphorylation. We hypothesized that CD46 provides protection to the bladder cancer cells against mAb therapies. Bladder cancer cells were also susceptible to cetuximab-mediated immunologic anti-tumor effects. Further, cetuximab enhanced the cell killing by activating both antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in bladder cancer cells. Restoration of CD46 expression protected the cells from both CDC and ADCC induced by cetuximab. Together, CD46 exhibited a cancer-protective effect against both direct (by involvement of PBMC or complement) and indirect cytotoxic activity by cetuximab in bladder cancer cells. Considering its clinical importance, CD46 could be an important link in the action mechanism of ADCC and CDC intercommunication and may be used for the development of novel therapeutic strategies.

The Association of R-Loop Binding Proteins Subtypes with CIN Implicates Therapeutic Strategies in Colorectal Cancer

Chromosomal instability (CIN) covers approximately 65 to 70% of colorectal cancer patients and plays an essential role in cancer progression. However, the molecular features and therapeutic strategies related to those patients are still controversial. R-loop binding proteins (RLBPs) exert significant roles in transcription and replication. Here, integrative colorectal cancer proteogenomic analysis identified two RLBPs subtypes correlated with distinct prognoses. Cluster I (CI), represented by high expression of RLBPs, was associated with the CIN phenotype. While Cluster II (CII) with the worst prognosis and low expression of RLBPs was composed of a high percentage of patients with mucinous adenocarcinoma or right-sided colon cancer. The molecular feature analysis revealed that the active RNA processing, ribosome synthesis, and aberrant DNA damage repair were shown in CI, a high inflammatory signaling pathway, and lymphocyte infiltration was enriched in CII. In addition, we revealed 42 tumor-associated RLBPs proteins. The CI with high expression of tumor-associated proteins was sensitive to drugs targeting genome integrity and EGFR in both cell and organoid models. Thus, our study unveils a significant molecular association of the CIN phenotype with RLBPs, and also provides a powerful resource for further functional exploration of RLBPs in cancer progression and therapeutic application.

Discovering and Targeting Dynamic Drugging Pockets of Oncogenic Proteins: The Role of Magnesium in Conformational Changes of the G12D Mutated Kirsten Rat Sarcoma-Guanosine Diphosphate Complex

KRAS-G12D mutations are the one of most frequent oncogenic drivers in human cancers. Unfortunately, no therapeutic agent directly targeting KRAS-G12D has been clinically approved yet, with such mutated species remaining undrugged. Notably, cofactor Mg2+ is closely related to the function of small GTPases, but no investigation has been conducted yet on Mg2+ when associated with KRAS. Herein, through microsecond scale molecular dynamics simulations, we found that Mg2+ plays a crucial role in the conformational changes of the KRAS-GDP complex. We located two brand new druggable dynamic pockets exclusive to KRAS-G12D. Using the structural characteristics of these two dynamic pockets, we designed in silico the inhibitor DBD15-21-22, which can specifically and tightly target the KRAS-G12D-GDP-Mg2+ ternary complex. Overall, we provide two brand new druggable pockets located on KRAS-G12D and suitable strategies for its inhibition.

Molecular Analyses in Peritoneal Metastasis from Colorectal Cancer: A Review-An English Version

Despite a trend showing continued improvement in survival by combing targeted agents in colorectal cancer, the improvement was limited, and clinically meaningful benefits were not achieved in peritoneal metastasis. The role of cytoreductive surgery (CRS) and proportion of the benefit from hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. The PRODIGE 7 study aimed to assess the specific contribution of HIPEC to the survival benefit of peritoneal metastasis from colorectal cancer (CRC-PM) by grouping CRS alone versus CRS with oxaliplatin-based HIPEC, but failed to show any survival improvement. Of these criticisms, oxaliplatin resistance was suggested as the main cause of the negative result. In this regard, the relative resistance to oxaliplatin in consensus molecular subtype 4 colorectal cancer (CRC) is of great interest. Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology such as next generation sequencing. This review aimed to provide an overview of the current status of studies reporting the molecular knowledge of CRC-PM.

Molecular analyses of peritoneal metastasis from colorectal cancer

Background: Despite a trend showing continued improvement in survival by combing targeted agents for colorectal cancer (CRC), the improvement observed is limited. Moreover, clinically relevant benefits were not achieved in peritoneal metastasis cases. The role of cytoreductive surgery (CRS) and the benefits of hyperthermic intraperitoneal chemotherapy (HIPEC) have been questioned. This review aimed to provide an overview of the current status of the studies reporting on the molecular knowledge of peritoneal metastasis from CRC (CRC-PM).Current Concepts: The PRODIGE 7 study was performed to assess the specific contributions of HIPEC to the survival benefit in CRC-PM cases by comparing CRS treatment alone and CRS with oxaliplatin-based HIPEC. However, this study did not reveal any survival improvement, and oxaliplatin resistance was suggested as the main cause of this negative outcome. Hence, the relative resistance to oxaliplatin in consensus molecular subtype (CMS) 4 CRC is of great interest.Discussion and Conclusion: Recent treatments for metastatic CRC have gradually moved to precision medicine based on individual biological information through high-throughput technology, such as next-generation sequencing. In the transcriptome study, CRC-PM was identified as an almost homogeneous CMS4 classification, which is known to have strong resistance to oxaliplatin-based chemotherapy. These results suggest the need to clarify complex sub-signal transmission pathways derived from transcriptome or proteome studies of CRC-PM. Finally, to compare two studies, it is necessary to establish a representative patient group and consider standardized sample collection, treatment, and analysis.

Metabolic-Dysregulation-Based iEESI-MS Reveals Potential Biomarkers Associated with Early-Stage and Progressive Colorectal Cancer

The application of rapid and accurate diagnostic methods can improve colorectal cancer (CRC) survival rates dramatically. Here, we used a non-targeted metabolic analysis strategy based on internal extractive electrospray ionization mass spectrometry (iEESI-MS) to detect metabolite ions associated with the progression of CRC from 172 tissues (45 stage I/II CRC, 41 stage III/IV CRC, and 86 well-matched normal tissues). A support vector machine (SVM) model based on 10 differential metabolite ions for differentiating early-stage CRC from normal tissues was built with a good prediction accuracy of 92.6%. The biomarker panel consisting of lysophosphatidylcholine (LPC) (18:0) has good diagnostic potential in differentiating early-stage CRC from advanced-stage CRC. We showed that the down-regulation of LPC (18:0) in tumor tissues is associated with CRC progression and related to the regulation of the epidermal growth factor receptor. Pathway analysis showed that metabolic pathways in CRC are related to glycerophospholipid metabolism and purine metabolism. In conclusion, we built an SVM model with good performance to distinguish between early-stage CRC and normal groups based on iEESI-MS and found that LPC (18:0) is associated with the progression of CRC.

Mouse Models for Application in Colorectal Cancer: Understanding the Pathogenesis and Relevance to the Human Condition

Colorectal cancer (CRC) is a malignant disease that is the second most common cancer worldwide. CRC arises from the complex interactions among a variety of genetic and environmental factors. To understand the mechanism of colon tumorigenesis, preclinical studies have developed various mouse models including carcinogen-induced and transgenic mice to recapitulate CRC in humans. Using these mouse models, scientific breakthroughs have been made on the understanding of the pathogenesis of this complex disease. Moreover, the availability of transgenic knock-in or knock-out mice further increases the potential of CRC mouse models. In this review, the overall features of carcinogen-induced (focusing on azoxymethane and azoxymethane/dextran sulfate sodium) and transgenic (focusing on Apc^Min/+) mouse models, as well as their mechanisms to induce colon tumorigenesis, are explored. We also discuss limitations of these mouse models and their applications in the evaluation and study of drugs and treatment regimens against CRC. Through these mouse models, a better understanding of colon tumorigenesis can be achieved, thereby facilitating the discovery of novel therapeutic strategies against CRC.

Clinical management of metastatic colorectal cancer in the era of precision medicine

Colorectal cancer (CRC) represents approximately 10% of all cancers and is the second most common cause of cancer deaths. Initial clinical presentation as metastatic CRC (mCRC) occurs in approximately 20% of patients. Moreover, up to 50% of patients with localized disease eventually develop metastases. Appropriate clinical management of these patients is still a challenging medical issue. Major efforts have been made to unveil the molecular landscape of mCRC. This has resulted in the identification of several druggable tumor molecular targets with the aim of developing personalized treatments for each patient. This review summarizes the improvements in the clinical management of patients with mCRC in the emerging era of precision medicine. In fact, molecular stratification, on which the current treatment algorithm for mCRC is based, although it does not completely represent the complexity of this disease, has been the first significant step toward clinically informative genetic profiling for implementing more effective therapeutic approaches. This has resulted in a clinically relevant increase in mCRC disease control and patient survival. The next steps in the clinical management of mCRC will be to integrate the comprehensive knowledge of tumor gene alterations, of tumor and microenvironment gene and protein expression profiling, of host immune competence as well as the application of the resulting dynamic changes to a precision medicine-based continuum of care for each patient. This approach could result in the identification of individual prognostic and predictive parameters, which could help the clinician in choosing the most appropriate therapeutic program(s) throughout the entire disease journey for each patient with mCRC. CA Cancer J Clin. 2022;72:000-000.

Depleting receptor tyrosine kinases EGFR and HER2 overcomes resistance to EGFR inhibitors in colorectal cancer

BACKGROUND

Epidermal growth factor receptor (EGFR) inhibitors, including cetuximab and panitumumab, are valuable therapeutics for colorectal cancer (CRC), but resistance to these inhibitors is common. The reason for such resistance is not well understood, which hampers development of better therapeutic strategies. Although activating mutations in KRAS, BRAF and PIK3CA are considered major drivers of CRC resistance to EGFR inhibitors, therapeutic targeting of these drug resistance drivers has not produced substantial clinical benefit.

METHODS

We exploited cell lines and mouse tumor models (cell line xenografts and patient derived xenografts) for experiments of genetic and pharmacologic depletion of EGFR and/or its family member HER2, including EGFR mutants, inhibition of EGFR ligand shedding, and biochemical analysis of signaling proteins, to delineate the mechanism of CRC resistance to EGFR inhibitors and to assess the therapeutic activity of PEPDG278D, which is a recombinant human protein that induces the degradation of both EGFR and HER2.

RESULTS

The sensitivity of CRC cells to cetuximab and panitumumab correlates with the ability of these drugs to induce EGFR downregulation. PEPDG278D strongly inhibits oncogenic signaling and growth of CRC cells by causing profound depletion of EGFR and HER2, regardless of activating mutations of KRAS, BRAF and PIK3CA. siRNA knockdown of EGFR or HER2 also inhibits CRC cells resistant to EGFR inhibitors. Tumors harboring mutated KRAS, BRAF and/or PIK3CA also overexpress EGFR ligands, further suggesting that EGFR signaling remains important to the tumors. While excessive tumor-generated high-affinity EGFR ligands block target engagement by PEPDG278D, aderbasib, an inhibitor of ADAM10 and ADAM17, enables PEPDG278D to exert strong antitumor activity by inhibiting ligand shedding. Moreover, adding fluorouracil, which is commonly used in CRC treatment, to the combination of PEPDG278D and aderbasib further enhances tumor inhibition.

CONCLUSIONS

Our study shows that CRC resistance to EGFR inhibitors results primarily from the inability of the inhibitors to downregulate their target and that a PEPDG278D-based combination treatment overcomes the resistance.

Triple Targeting of HER Receptors Overcomes Heregulin-mediated Resistance to EGFR Blockade in Colorectal Cancer

Current treatment options for patients with advanced colorectal cancers include anti-EGFR/HER1 therapy with the blocking antibody cetuximab. Although a subset of patients with KRAS WT disease initially respond to the treatment, resistance develops in almost all cases. Relapse has been associated with the production of the ligand heregulin (HRG) and/or compensatory signaling involving the receptor tyrosine kinases HER2 and HER3. Here, we provide evidence that triple-HER receptor blockade based on a newly developed bispecific EGFR×HER3-targeting antibody (scDb-Fc) together with the HER2-blocking antibody trastuzumab effectively inhibited HRG-induced HER receptor phosphorylation, downstream signaling, proliferation, and stem cell expansion of DiFi and LIM1215 colorectal cancer cells. Comparative analyses revealed that the biological activity of scDb-Fc plus trastuzumab was sometimes even superior to that of the combination of the parental antibodies, with PI3K/Akt pathway inhibition correlating with improved therapeutic response and apoptosis induction as seen by single-cell analysis. Importantly, growth suppression by triple-HER targeting was recapitulated in primary KRAS WT patient-derived organoid cultures exposed to HRG. Collectively, our results provide strong support for a pan-HER receptor blocking approach to combat anti-EGFR therapy resistance of KRAS WT colorectal cancer tumors mediated by the upregulation of HRG and/or HER2/HER3 signaling.

Liquid profiling of circulating tumor DNA in colorectal cancer: steps needed to achieve its full clinical value as standard care

The analysis of circulating tumor DNA (ctDNA) is at the threshold of implementation into standard care for colorectal cancer (CRC) patients. However, data about the clinical utility of liquid profiling (LP), its acceptance by clinicians, and its integration into clinical workflows in real-world settings remain limited. Here, LP tests requested as part of routine care since 2016 were retrospectively evaluated. Results show restrained request behavior that improved moderately over time, as well as reliable diagnostic performance comparable to translational studies, with an overall agreement of 91.7%. Extremely low ctDNA levels at < 0.1% in over 20% of cases, a high frequency of concomitant driver mutations (in up to 14% of cases), and ctDNA levels reflecting the clinical course of disease were revealed. However, certain limitations hampering successful translation of ctDNA into clinical practice were uncovered, including the lack of clinically relevant ctDNA thresholds, appropriate time points of LP requests, and integrative evaluation of ctDNA, imaging, and clinical findings. In conclusion, these results highlight the potential clinical value of LP for CRC patient management and demonstrate issues that need to be addressed for successful long-term implementation in clinical workflows.

Genomic alterations in cholangiocarcinoma: clinical significance and relevance to therapy

Improving the survival of patients with cholangiocarcinoma (CCA) has long proved challenging, although the treatment of this disease nowadays is on advancement. The historical invariability of survival outcomes and the limited number of agents known to be effective in the treatment of this disease has increased the number of studies designed to identify genetic targetable hits that can be efficacious for novel therapies. In this respect, the increasing feasibility of molecular profiling starting either from tumor tissue or circulating cell-free DNA (cfDNA) has led to an increased understanding of CCA biology. Intrahepatic CCA (iCCA) and extrahepatic CCA (eCCA) display different and typical patterns of actionable genomic alterations, which offer opportunity for therapeutic intervention. This review article will summarize the current knowledge on the genomic alterations of iCCA and eCCA, provide information on the main technologies for genomic profiling using either tumor tissue or cfDNA, and briefly discuss the main clinical trials with targeted agents in this disease.

Non-Coding RNAs in Colorectal Cancer: Their Functions and Mechanisms

Colorectal cancer (CRC) is a common malignancy with high mortality. However, the molecular mechanisms underlying CRC remain unclear. Controversies over the exact functions of non-coding RNAs (ncRNAs) in the progression of CRC have been prevailing for multiple years. Recently, accumulating evidence has demonstrated the regulatory roles of ncRNAs in various human cancers, including CRC. The intracellular signaling pathways by which ncRNAs act on tumor cells have been explored, and in CRC, various studies have identified numerous dysregulated ncRNAs that serve as oncogenes or tumor suppressors in the process of tumorigenesis through diverse mechanisms. In this review, we have summarized the functions and mechanisms of ncRNAs (mainly lncRNAs, miRNAs, and circRNAs) in the tumorigenesis of CRC. We also discuss the potential applications of ncRNAs as diagnostic and prognostic tools, as well as therapeutic targets in CRC. This review details strategies that trigger the recognition of CRC-related ncRNAs, as well as the methodologies and challenges of studying these molecules, and the forthcoming clinical applications of these findings.

Identification of Tissue Types and Gene Mutations From Histopathology Images for Advancing Colorectal Cancer Biology

Objective: Colorectal cancer (CRC) patients respond differently to treatments and are sub-classified by different approaches. We evaluated a deep learning model, which adopted endoscopic knowledge learnt from AI-doscopist, to characterise CRC patients by histopathological features. Results: Data of 461 patients were collected from TCGA-COAD database. The proposed framework was able to 1) differentiate tumour from normal tissues with an Area Under Receiver Operating Characteristic curve (AUROC) of 0.97; 2) identify certain gene mutations (MYH9, TP53) with an AUROC > 0.75; 3) classify CMS2 and CMS4 better than the other subtypes; and 4) demonstrate the generalizability of predicting KRAS mutants in an external cohort. Conclusions: Artificial intelligent can be used for on-site patient classification. Although KRAS mutants were commonly associated with therapeutic resistance and poor prognosis, subjects with predicted KRAS mutants in this study have a higher survival rate in 30 months after diagnoses.

Identification of RAS mutant biomarkers for EGFR inhibitor sensitivity using a systems biochemical approach

Mutations can be important biomarkers that influence the selection of specific cancer treatments. We recently combined mathematical modeling of RAS signaling network biochemistry with experimental cancer cell biology to determine why KRAS G13D is a biomarker for sensitivity to epidermal growth factor receptor (EGFR)-targeted therapies. The critical mechanistic difference between KRAS G13D and the other most common KRAS mutants is impaired binding to tumor suppressor Neurofibromin (NF1). Here, we hypothesize that impaired binding to NF1 is a "biophysical biomarker" that defines other RAS mutations that retain therapeutic sensitivity to EGFR inhibition. Both computational and experimental investigations support our hypothesis. By screening RAS mutations for this biophysical characteristic, we identify 10 additional RAS mutations that appear to be biomarkers for sensitivity to EGFR inhibition. Altogether, this work suggests that personalized medicine may benefit from migrating from gene-based and allele-based biomarker strategies to biomarkers based on biophysically defined subsets of mutations.

K-RAS4A: Lead or Supporting Role in Cancer Biology?

The RAS oncogene is one of the most frequently mutated genes in human cancer, with K-RAS having a leading role in tumorigenesis. K-RAS undergoes alternative splicing, and as a result its transcript generates two gene products K-RAS4A and K-RAS4B, which are affected by the same oncogenic mutations, are highly homologous, and are expressed in a variety of human tissues at different levels. In addition, both isoforms localise to the plasma membrane by distinct targeting motifs. While some evidence suggests nonredundant functions for both splice variants, most work to date has focused on K-RAS4B, or even just K-RAS (i.e., without differentiating between the splice variants). This review aims to address the most relevant evidence published regarding K-RAS4A and to discuss if this “minor” isoform could also play a leading role in cancer, concluding that a significant body of evidence supports a leading role rather than a supporting (or secondary) role for K-RAS4A in cancer biology.

Precision Medicine for Colorectal Cancer with Liquid Biopsy and Immunotherapy

Simple Summary

There are some challenges to improve the clinical outcome of colorectal cancers (CRCs) by implementing new technologies, such as early detection of recurrence/relapse and selection of appropriate drugs based on the genomic profiles of tumors. For example, the genomic characteristics of tumors can be analyzed by blood-based tests, namely ‘liquid biopsies’, which are minimally-invasive and can be performed repeatedly during the treatment course. Hence, liquid biopsies are considered to hold great promise to fill these gaps in clinical routines. In this review, we addressed clinical usefulness of liquid biopsies in the clinical management of CRC patients, including cancer screening, detection of minimal residual disease, selection of appropriate molecular-targeted drugs, monitoring of the treatment responsiveness, and very early detection of recurrence/relapse of the disease. Furthermore, we discussed the possibility of adoptive T cell therapies and a future personalized immunotherapy based on tumor genome information.

Abstract

In the field of colorectal cancer (CRC) treatment, diagnostic modalities and chemotherapy regimens have progressed remarkably in the last two decades. However, it is still difficult to identify minimal residual disease (MRD) necessary for early detection of recurrence/relapse of tumors and to select and provide appropriate drugs timely before a tumor becomes multi-drug-resistant and more aggressive. We consider the leveraging of in-depth genomic profiles of tumors as a significant breakthrough to further improve the overall prognosis of CRC patients. With the recent technological advances in methodologies and bioinformatics, the genomic profiles can be analyzed profoundly without delay by blood-based tests—‘liquid biopsies’. From a clinical point of view, a minimally-invasive liquid biopsy is thought to be a promising method and can be implemented in routine clinical settings in order to meet unmet clinical needs. In this review, we highlighted clinical usefulness of liquid biopsies in the clinical management of CRC patients, including cancer screening, detection of MRD, selection of appropriate molecular-targeted drugs, monitoring of the treatment responsiveness, and very early detection of recurrence/relapse of the disease. In addition, we addressed a possibility of adoptive T cell therapies and a future personalized immunotherapy based on tumor genome information.

Microbiome in drug resistance to colon cancer

Metagenomic analyses have revealed microbial dysbiosis in the gut of patients with colorectal cancer (CRC). The gut microbiota influences CRC via a variety of mechanisms, including microbial-derived factors such as metabolites or genotoxins. Pathogenic drivers and opportunistic passenger bacteria may underlie direct effect of the gut microbiota on carcinogenesis. We posit that metabolites generated by gut microbiota can influence CRC through a multitude of epigenetic or genetic effects on malignant transformation. A closer look at the cross talks between the commensals, epithelial cells, immune regulators etc., needs to be established with more substantiated studies. The recurrence of chemoresistant disease following therapy undoubtedly provides the impetus for morbidity and mortality; yet, the role of gut microbiome in drug resistance remains to be fully investigated. We review the current literature on microbial dysbiosis during CRC and discuss the mechanistic basis of CRC-associated bacteria in tumor initiation, progression and drug resistance.

RNF141 interacts with KRAS to promote colorectal cancer progression

RING finger proteins (RNFs) play a critical role in cancer initiation and progression. RNF141 is a member of RNFs family; however, its clinical significance, roles, and mechanism in colorectal cancer (CRC) remain poorly understood. Here, we examined the expression of RNF141 in 64 pairs of CRC and adjacent normal tissues by real-time PCR, Western blot, and immunohistochemical analysis. We found that there was more expression of RNF141 in CRC tissue compared with its adjacent normal tissue and high RNF141 expression associated with T stage. In vivo and in vitro functional experiments were conducted and revealed the oncogenic role of RNF141 in CRC. RNF141 knockdown suppressed proliferation, arrested the cell cycle in the G1 phase, inhibited migration, invasion and HUVEC tube formation but promoted apoptosis, whereas RNF141 overexpression exerted the opposite effects in CRC cells. The subcutaneous xenograft models showed that RNF141 knockdown reduced tumor growth, but its overexpression promoted tumor growth. Mechanistically, liquid chromatography-tandem mass spectrometry indicated RNF141 interacted with KRAS, which was confirmed by Co-immunoprecipitation, Immunofluorescence assay. Further analysis with bimolecular fluorescence complementation (BiFC) and Glutathione-S-transferase (GST) pull-down assays showed that RNF141 could directly bind to KRAS. Importantly, the upregulation of RNF141 increased GTP-bound KRAS, but its knockdown resulted in a reduction accordingly. Next, we demonstrated that RNF141 induced KRAS activation via increasing its enrichment on the plasma membrane not altering total KRAS expression, which was facilitated by the interaction with LYPLA1. Moreover, KRAS silencing partially abolished the effect of RNF141 on cell proliferation and apoptosis. In addition, our findings presented that RNF141 functioned as an oncogene by upregulating KRAS activity in a manner of promoting KRAS enrichment on the plasma membrane in CRC.

Prospective Evaluation of Radiotherapy-Induced Immunologic and Genetic Effects in Colorectal Cancer Oligo-Metastatic Patients with Lung-Limited Disease: The PRELUDE-1 Study

BACKGROUND

in recent years, the management of advanced colorectal cancer (CRC) has been greatly improved with integrated strategies including stereotactic radiation therapy (SRT). The administration of SRT has been demonstrated, particularly in oligo-metastatic (om) CRC, to be a safe and effective option. Interestingly, it has been demonstrated that SRT can induce regression of tumors in non-irradiated regions ("abscopal effect") through stimulation of anti-tumor immune effects ("radiation-induced immunity"). We have recently shown that lung-limited omCRC is characterized by regression of tumor clones bearing specific key driver gene mutations.

AIMS

to assess the genetic evolution on tumor cancer cells induced by SRT in lung-limited omCRC. Secondary objectives included descriptions of the abscopal effect, responses' duration, toxicity, and progression-free survival. A translational research will be performed to evaluate tumor genetic evolution (through liquid biopsies and Next Generation Sequencing), HLA class I repertoire, peripheral immune cells, and cytokine dynamics.

METHODS

PRELUDE-1 is a prospective translational study. SRT will be administered only to the largest nodule (with a maximum diameter ≤ 25 mm) in omCRC with two or three radiologically evident lesions. The sample size is based on the innovative hypothesis that radiation-induced immunity could induce regression of tumor clones bearing KRAS oncogene mutations. According to the binomial test, considering the frequency of KRAS mutations and assuming a probability of mutant KRAS→wild type KRAS of p0 = 0.0077, with α = 0.05 and 1-β = 0.60, the final sample size is 25 patients.

Automation of Organoid Cultures: Current Protocols and Applications

GRAPHICAL ABSTRACT

[Formula: see text].

RNA-binding protein IMP3 is a novel regulator of MEK1/ERK signaling pathway in the progression of colorectal Cancer through the stabilization of MEKK1 mRNA

Background

MEK1/ERK signaling pathway plays an important role in most tumor progression, including colorectal cancer (CRC), however, MEK1-targeting therapy has little effective in treating CRC patients, indicating there may be a complex mechanism to activate MEK1/ERK signaling pathway except RAS activated mechanism.

Methods

To investigate the clinical significance of IMP3, we analyzed its expression levels in publicly available dataset and samples from Fudan University Shanghai Cancer Center. The effects of IMP3 on proliferation, migration, and invasion were determined by in vitro and in vivo experiments. To investigate the role of IMP3 in colon carcinogenesis, conditional IMP3 knockout C57BL/6 mice was generated. The IMP3/MEKK1/MEK/ERK signaling axis in CRC was screened and validated by RNA-sequencing, RNA immunoprecipitation, luciferase reporter and western blot assays.

Results

We find RNA binding protein IMP3 directly bind to MEKK1 mRNA 3′-UTR, which regulates its stability, promote MEKK1 expression and sequentially activates MEK1/ERK signaling. Functionally, IMP3 promote the malignant biological process of CRC cells via MEKK1/MEK1/ERK signaling pathway both in vitro and in vivo, Moreover, IMP3^−/− mice show decreased the expression of MEKK1 as well as colorectal tumors compared with wild-type mice after treatment with azoxymethane/dextran sodium sulfate. Clinically, the expression of IMP3 and MEKK1 are positive correlated, and concomitant IMP3 and MEKK1 protein levels negatively correlate with metastasis in CRC patients. In addition, MEK1 inhibitor in combination with shRNA-IMP3 have a synergistic effect both in vitro and in vivo.

Conclusion

Our study demonstrates that IMP3 regulates MEKK1 in CRC, thus activating the MEK1/ERK signaling in the progression of colorectal cancer, Furthermore, these results provide new insights into potential applications for combining MEK1 inhibitors with other target therapy such as IMP3 in preclinical trials for CRC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01994-8.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Beyond Microsatellite Instability: Evolving Strategies Integrating Immunotherapy for Microsatellite Stable Colorectal Cancer

OPINION STATEMENT

Advanced colorectal cancer (CRC) is a heterogeneous disease, characterized by several subtypes with distinctive genetic and epigenetic patterns. During the last years, immune checkpoint inhibitors (ICIs) have revamped the standard of care of several tumors such as non-small cell lung cancer and melanoma, highlighting the role of immune cells in tumor microenvironment (TME) and their impact on cancer progression and treatment efficacy. An "immunoscore," based on the percentage of two lymphocyte populations both at tumor core and invasive margin, has been shown to improve prediction of treatment outcome when added to UICC-TNM classification. To date, pembrolizumab, an anti-programmed death protein 1 (PD1) inhibitor, has gained approval as first-line therapy for mismatch-repair-deficient (dMMR) and microsatellite instability-high (MSI-H) advanced CRC. On the other hand, no reports of efficacy have been presented in mismatch-repair-proficient (pMMR) and microsatellite instability-low (MSI-L) or microsatellite stable (MSS) CRC. This group includes roughly 95% of all advanced CRC, and standard chemotherapy, in addition to anti-EGFR or anti-angiogenesis drugs, still represents first treatment choice. Hopefully, deeper understanding of CRC immune landscape and of the impact of specific genetic and epigenetic alterations on tumor immunogenicity might lead to the development of new drug combination strategies to overcome ICIs resistance in pMMR CRC, thus paving the way for immunotherapy even in this subgroup.

Equipping Natural Killer Cells with Cetuximab through Metabolic Glycoengineering and Bioorthogonal Reaction for Targeted Treatment of KRAS Mutant Colorectal Cancer

While Cetuximab can be used to treat KRAS wild-type colon cancer cells by targeting EGFR and inhibiting the activation of downstream signaling pathways, it exhibits little therapeutic effect on KRAS mutant colon cancer cells. Natural killer (NK) cells are a class of powerful immune cells with anticancer activities. However, NK cells typically lack inherent tumor targeting abilities. Here, a new method is established to bestow NK-92 cells with tumor targeting abilities by installing cetuximab on the cell surface. Through metabolic glycoengineering, azide groups were introduced onto the surface of NK-92 cells. Bioorthogonal strain promoted the azide-alkyne cycloaddition click reaction of engineered NK-92 cells with alkyne modified cetuximab functionalized NK cells with the antibody. The resulting NK-92 cells were significantly more effective than the parent NK-92 cells in protecting against tumor development in a KRAS mutant mouse tumor model resistant to cetuximab treatment. Thus, NK cell functionalization with antibodies enabled by metabolic glycoengineering is a promising strategy to enhance anticancer immune therapy.

Role of thyroid hormone-integrin αvβ3-signal and therapeutic strategies in colorectal cancers

Thyroid hormone analogues-particularly, L-thyroxine (T₄) has been shown to be relevant to the functions of a variety of cancers. Integrin αvβ3 is a plasma membrane structural protein linked to signal transduction pathways that are critical to cancer cell proliferation and metastasis. Thyroid hormones, T₄ and to a less extend T₃ bind cell surface integrin αvβ3, to stimulate the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway to stimulate cancer cell growth. Thyroid hormone analogues also engage in crosstalk with the epidermal growth factor receptor (EGFR)-Ras pathway. EGFR signal generation and, downstream, transduction of Ras/Raf pathway signals contribute importantly to tumor cell progression. Mutated Ras oncogenes contribute to chemoresistance in colorectal carcinoma (CRC); chemoresistance may depend in part on the activity of ERK1/2 pathway. In this review, we evaluate the contribution of thyroxine interacting with integrin αvβ3 and crosstalking with EGFR/Ras signaling pathway non-genomically in CRC proliferation. Tetraiodothyroacetic acid (tetrac), the deaminated analogue of T₄, and its nano-derivative, NDAT, have anticancer functions, with effectiveness against CRC and other tumors. In Ras-mutant CRC cells, tetrac derivatives may overcome chemoresistance to other drugs via actions initiated at integrin αvβ3 and involving, downstream, the EGFR-Ras signaling pathways.

Systemic therapy in addition to cytoreduction and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases: recent insights from clinical studies and translational research

There is a lack of randomized or high-quality intention-to-treat cohort studies addressing the role of systemic therapy in addition to cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) as part of the treatment of colorectal peritoneal metastases (PM). Therefore, the choice whether or not to treat patients with systemic therapy is currently mainly based on expert opinion. As a result, treatment with neoadjuvant and/or adjuvant systemic therapy is implemented in various ways around the world. The aim of this review was to provide an overview of recent insights with regard to the systemic treatment of PM of colorectal origin obtained from clinical studies and translational research.

The role of the glutamine transporter ASCT2 in antineoplastic therapy

Cancer cells are metabolically reprogrammed to support their high rates of proliferation, continuous growth, survival, invasion, metastasis, and resistance to cancer treatments. Among changes in cancer cell bioenergetics, the role of glutamine metabolism has been receiving increasing attention. Increased glutaminolysis in cancer cells is associated with increased expression of membrane transporters that mediate the cellular uptake of glutamine. ASCT2 (Alanine, Serine, Cysteine Transporter 2) is a Na⁺-dependent transmembrane transporter overexpressed in cancer cells and considered to be the primary transporter for glutamine in these cells. The possibility of inhibiting ASCT2 for antineoplastic therapy is currently under investigation. In this article, we will present the pharmacological agents currently known to act on ASCT2, which have been attracting attention in antineoplastic therapy research. We will also address the impact of ASCT2 inhibition on the prognosis of some cancers. We conclude that ASCT2 inhibition and combination of ASCT2 inhibitors with other anti-tumor therapies may be a promising antineoplastic strategy. However, more research is needed in this area.

Aflibercept or bevacizumab in combination with FOLFIRI as second-line treatment of mRAS metastatic colorectal cancer patients: the ARBITRATION study protocol

Background:

The intensive study of predictive factors has strongly ameliorated the therapeutic flow-chart of metastatic colorectal cancer (mCRC) by allowing the selection of patients who benefit from specific therapies. For instance, in mRAS (mutated RAS) mCRC patients, anti-EGFR drugs (cetuximab and panitumumab) are not recommended; in this group of patients, the use of anti-angiogenic drugs (bevacizumab and aflibercept) is predominant. However, at progression to standard bevacizumab-based first-line chemotherapy, still to date, there are no studies to guide oncologists in the choice of the best second-line anti-angiogenic drug (bevacizumab beyond progression versus aflibercept).

Methods:

ARBITRATION is a prospective, observational study assessing efficacy differences between second-line fluorouracil/irinotecan (FOLFIRI)/bevacizumab versus FOLFIRI/aflibercept at progression to fluoropyrimidines, oxaliplatin and bevacizumab in mRAS mCRC patients. A test power of 80%, a median survival of 9 months from second-line treatment start and a hazard ratio of 0.67 between the two schedules were the basis for statistical design. The final sample will be 220 patients (110 per treatment). The significance will be verified with a two-tailed log-rank test with an alpha value of the I-type error of 5%. Time-to-outcome will be described by Kaplan–Meier curves and prognostic factors studied through multivariable analyses based on the Cox model. Secondary objectives include safety, responses’ duration and progression-free survival. A translational research will be conducted to measure several angiogenic proteins in patients’ serum before starting the therapy in order to evidence any angiogenic factor patterns related to outcome.

Discussion:

We present a large, prospective, observational study aiming to answer two scientific questions: (1) outcome differences between second-line treatments with FOLFIRI/bevacizumab beyond progression versus FOLFIRI/aflibercept in mRAS mCRC patients, (2) angiogenic factors’ patterns that could associate with efficacy and help oncologists to apply best the therapeutic anti-angiogenic strategies.

Trial registration:

The ARBITRATION trial (version 0.0, 13 April 2020) has been registered into the clinicaltrials.gov registry on 20 May 2020 with identifier NCT04397601.