Drug resistance in colorectal cancer: An epigenetic overview

A novel Senescence-Based prognostic model unveils tumor interactions and drug resistance in colorectal cancer

BACKGROUND

In China, CRC incidence is escalating. The main hurdles are heterogeneity and drug resistance. This research delves into cellular senescence in CRC, aiming to devise a prognostic model and pinpoint mechanisms impacting drug resistance.

METHODS

Mendelian randomization (MR) analysis confirmed the association between CRC and cellular aging. The Cancer Genome Atlas (TCGA)-CRC data served as the training set, with GSE38832 and GSE39582 as validation sets. Various bioinformatics methods were employed to construct and validate a risk model. CRC cells with NADPH Oxidase 4 (NOX4) knockout were generated using CRISPR-Cas9 technology. Protein blotting and colony formation assays elucidated the role of NOX4 in CRC cell aging and drug resistance.

RESULTS

A prognostic model, derived from dataset analysis, uncovered a link between high-risk groups and cancer progression. Notable differences in the tumor microenvironment were observed between risk groups. Finally, NOX4 was found to be linked with aging and drug resistance in CRC.

CONCLUSION

This research presents a novel senescence-based CRC prognosis model. It identifies NOX4's role in CRC drug resistance, suggesting it is a potential treatment target.

The epigenetic landscape in intestinal stem cells and its deregulation in colorectal cancer

Epigenetic mechanisms play a pivotal role in controlling gene expression and cellular plasticity in both normal physiology and pathophysiological conditions. These mechanisms are particularly important in the regulation of stem cell self-renewal and differentiation, both in embryonic development and within adult tissues. A prime example of this finely tuned epigenetic control is observed in the gastrointestinal lining, where the small intestine undergoes renewal approximately every 3-5 days. How various epigenetic mechanisms modulate chromatin functions in intestinal stem cells (ISCs) is currently an active area of research. In this review, we discuss the main epigenetic mechanisms that control ISC differentiation under normal homeostasis. Furthermore, we explore the dysregulation of these mechanisms in the context of colorectal cancer (CRC) development. By outlining the main epigenetic mechanisms contributing to CRC, we highlight the recent therapeutics development and future directions for colorectal cancer research.

Enterotoxin-related genes PPFIA4 and SCN3B promote colorectal cancer development and progression

To identify the role of enterotoxin-related genes in colorectal cancer (CRC) development and progression. Upregulated differentially expressed genes shared by three out of five Gene Expression Omnibus (GEO) data sets were included to screen the key enterotoxin-induced oncogenes (EIOGs) according to criteria oncogene definition, enrichment, and protein-protein interaction (PPI) network analysis, followed by prognosis survival, immune infiltration, and protential drugs analyses was performed via integration of RNA-sequencing data and The Cancer Genome Atlas-derived clinical profiles. We screened nine common key EIOGs from at least three GEO data sets. A Cox proportional hazards regression models verified that more alive cases, decreased overall survival, and highest 4-year survival prediction in CRC patients with high-risk score. Protein tyrosine phosphatase receptor type F polypeptide-interacting protein alpha-4 (PPFIA4), STY11, SCN3B, and SPTBN5 were shared in the same PPI network. Immune infiltration results showed that SCN3B and synaptotagmin 11 expression were obviously associated with B cell, macrophage, myeloid dendritic cell, neutrophils, and T cell CD4+ and CD8+ in both colon adenocarcinoma and rectal adenocarcinoma. CHIR-99021, MLN4924, and YK4-279 were identified as the potential drugs for treatment. Finally, upregulated EIOGs genes PPFIA4 and SCN3B were found in colon adenocarcinoma and PPFIA4 and SCN3B were proved to promote cell proliferation and migration in vitro. We demonstrated here that EIOGs promoting a malignancy phenotype was related with poor survival and prognosis in CRC, which might be served as novel therapeutic targets in CRC management.

N6-methyladenosine-dependent signaling in colorectal cancer: Functions and clinical potential

Colorectal cancer (CRC) ranks as the third most prevalent malignancy worldwide. Despite the gradual expansion of therapeutic options for CRC, its clinical management remains a formidable challenge. And, because of the current dearth of technical means for early CRC screening, most patients are diagnosed at an advanced stage. Therefore, it is imperative to develop novel diagnostic and therapeutic tools for this disease. N6-methyladenosine (m6A), the predominant RNA modification in eukaryotes, can be recognized by m6A-specific methylated reading proteins to modulate gene expression. Studies have revealed that CRC disrupts m6A homeostasis through various mechanisms, thereby sustaining aberrant signal transduction and promoting its own progression. Consequently, m6A-based diagnostic and therapeutic strategies have garnered widespread attention. Although utilizing m6A as a biomarker and drug target has demonstrated promising feasibility, existing observations primarily stem from preclinical models; henceforth necessitating further investigation and resolution of numerous outstanding issues.

Understanding the role of DNA methylation in colorectal cancer: Mechanisms, detection, and clinical significance

Colorectal cancer (CRC) is one of the deadliest malignancies worldwide, ranking third in incidence and second in mortality. Remarkably, early stage localized CRC has a 5-year survival rate of over 90%; in stark contrast, the corresponding 5-year survival rate for metastatic CRC (mCRC) is only 14%. Compounding this problem is the staggering lack of effective therapeutic strategies. Beyond genetic mutations, which have been identified as critical instigators of CRC initiation and progression, the importance of epigenetic modifications, particularly DNA methylation (DNAm), cannot be underestimated, given that DNAm can be used for diagnosis, treatment monitoring and prognostic evaluation. This review addresses the intricate mechanisms governing aberrant DNAm in CRC and its profound impact on critical oncogenic pathways. In addition, a comprehensive review of the various techniques used to detect DNAm alterations in CRC is provided, along with an exploration of the clinical utility of cancer-specific DNAm alterations.

NOX4 promotes tumor progression through the MAPK-MEK1/2-ERK1/2 axis in colorectal cancer

BACKGROUND

Metabolic reprogramming plays a key role in cancer progression and clinical outcomes; however, the patterns and primary regulators of metabolic reprogramming in colorectal cancer (CRC) are not well understood.

AIM

To explore the role of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) in promoting progression of CRC.

METHODS

We evaluated the expression and function of dysregulated and survival-related metabolic genes using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. Consensus clustering was used to cluster CRC based on dysregulated metabolic genes. A prediction model was constructed based on survival-related metabolic genes. Sphere formation, migration, invasion, proliferation, apoptosis and clone formation was used to evaluate the biological function of NOX4 in CRC. mRNA sequencing was utilized to explore the alterations of gene expression NOX4 over-expression tumor cells. In vivo subcutaneous and lung metastasis mouse tumor model was used to explore the effect of NOX4 on tumor growth.

RESULTS

We comprehensively analyzed 3341 metabolic genes in CRC and identified three clusters based on dysregulated metabolic genes. Among these genes, NOX4 was highly expressed in tumor tissues and correlated with worse survival. In vitro, NOX4 overexpression induced clone formation, migration, invasion, and stemness in CRC cells. Furthermore, RNA-sequencing analysis revealed that NOX4 overexpression activated the mitogen-activated protein kinase-MEK1/2-ERK1/2 signaling pathway. Trametinib, a MEK1/2 inhibitor, abolished the NOX4-mediated tumor progression. In vivo, NOX4 overexpression promoted subcutaneous tumor growth and lung metastasis, whereas trametinib treatment can reversed the metastasis.

CONCLUSION

Our study comprehensively analyzed metabolic gene expression and highlighted the importance of NOX4 in promoting CRC metastasis, suggesting that trametinib could be a potential therapeutic drugs of CRC clinical therapy targeting NOX4.

Targeting the chromatin structural changes of antitumor immunity

Epigenomic imbalance drives abnormal transcriptional processes, promoting the onset and progression of cancer. Although defective gene regulation generally affects carcinogenesis and tumor suppression networks, tumor immunogenicity and immune cells involved in antitumor responses may also be affected by epigenomic changes, which may have significant implications for the development and application of epigenetic therapy, cancer immunotherapy, and their combinations. Herein, we focus on the impact of epigenetic regulation on tumor immune cell function and the role of key abnormal epigenetic processes, DNA methylation, histone post-translational modification, and chromatin structure in tumor immunogenicity, and introduce these epigenetic research methods. We emphasize the value of small-molecule inhibitors of epigenetic modulators in enhancing antitumor immune responses and discuss the challenges of developing treatment plans that combine epigenetic therapy and immunotherapy through the complex interaction between cancer epigenetics and cancer immunology.

EZH2/G9a interact to mediate drug resistance in non-small-cell lung cancer by regulating the SMAD4/ERK/c-Myc signaling axis

Drug resistance is the leading problem in non-small-cell lung cancer (NSCLC) therapy. The contribution of histone methylation in mediating malignant phenotypes of NSCLC is well known. However, the role of histone methylation in NSCLC drug-resistance mechanisms remains unclear. Here, our data show that EZH2 and G9a, two histone methyltransferases, are involved in the drug resistance of NSCLC. Gene manipulation results indicate that the combination of EZH2 and G9a promotes tumor growth and mediates drug resistance in a complementary manner. Importantly, clinical study demonstrates that co-expression of both enzymes predicts a poor outcome in patients with NSCLC. Mechanistically, G9a and EZH2 interact and promote the silencing of the tumor-suppressor gene SMAD4, activating the ERK/c-Myc signaling pathway. Finally, SU08, a compound targeting both EZH2 and G9a, is demonstrated to sensitize resistant cells to therapeutic drugs by regulating the SMAD4/ERK/c-Myc signaling axis. These findings uncover the resistance mechanism and a strategy for reversing NSCLC drug resistance.

Mitochondrial dynamics and colorectal cancer biology: mechanisms and potential targets

Colorectal cancer (CRC) is a significant public health concern, and its development is associated with mitochondrial dysfunction. Mitochondria can adapt to the high metabolic demands of cancer cells owing to their plasticity and dynamic nature. The fusion-fission dynamics of mitochondria play a crucial role in signal transduction and metabolic functions of CRC cells. Enhanced mitochondrial fission promotes the metabolic reprogramming of CRC cells, leading to cell proliferation, metastasis, and chemoresistance. Excessive fission can also trigger mitochondria-mediated apoptosis. In contrast, excessive mitochondrial fusion leads to adenosine triphosphate (ATP) overproduction and abnormal tumor proliferation, whereas moderate fusion protects intestinal epithelial cells from oxidative stress-induced mitochondrial damage, thus preventing colitis-associated cancer (CAC). Therefore, an imbalance in mitochondrial dynamics can either promote or inhibit CRC progression. This review provides an overview of the mechanism underlying mitochondrial fusion-fission dynamics and their impact on CRC biology. This revealed the dual role of mitochondrial fusion-fission dynamics in CRC development and identified potential drug targets. Additionally, this study partially explored mitochondrial dynamics in immune and vascular endothelial cells in the tumor microenvironment, suggesting promising prospects for targeting key fusion/fission effector proteins against CRC.

Epigenetic modifications: Key players in cancer heterogeneity and drug resistance

Cancer heterogeneity and drug resistance remain pivotal obstacles in effective cancer treatment and management. One major contributor to these challenges is epigenetic modifications - gene regulation that does not involve changes to the DNA sequence itself but significantly impacts gene expression. As we elucidate these phenomena, we underscore the pivotal role of epigenetic modifications in regulating gene expression, contributing to cellular diversity, and driving adaptive changes that can instigate therapeutic resistance. This review dissects essential epigenetic modifications - DNA methylation, histone modifications, and chromatin remodeling - illustrating their significant yet complex contributions to cancer biology. While these changes offer potential avenues for therapeutic intervention due to their reversible nature, the interplay of epigenetic and genetic changes in cancer cells presents unique challenges that must be addressed to harness their full potential. By critically analyzing the current research landscape, we identify knowledge gaps and propose future research directions, exploring the potential of epigenetic therapies and discussing the obstacles in translating these concepts into effective treatments. This comprehensive review aims to stimulate further research and aid in developing innovative, patient-centered cancer therapies. Understanding the role of epigenetic modifications in cancer heterogeneity and drug resistance is critical for scientific advancement and paves the way towards improving patient outcomes in the fight against this formidable disease.

Bufotalin-loaded biomimetic Prussian blue nanoparticles for colorectal cancer chemo-photothermal ferroptosis therapy

Purpose: We constructed biomimetic nanoparticles with biocompatible, tumor-targeting, laser-responsive properties for ferroptosis-induced colorectal cancer chemo-photothermal therapy, with the aim to realize double-hit ferroptosis treatment for colorectal cancer. Methods: The nanoparticles were prepared by first loading the chemotherapy drug bufotalin (CS-5) with Prussian blue (PB), then combining a hybridized erythrocyte-tumor membrane (M) with PB@CS-5 to produce PB@CS-5@M. The chemo-photothermal therapy efficiency of PB@CS-5@M was tested by in vitro and in vivo experiments. Results and conclusion: The combined PB and CS-5 act as promising ferroptosis inducers to enhance ferroptosis efficacy. The hyperthermia induced by laser stimulation can trigger PB to release CS-5 and iron and ferrous ions, which further promotes ferroptosis.

Photodynamic Therapy and Immunological View in Gastrointestinal Tumors

Gastrointestinal cancers are a specific group of oncological diseases in which the location and nature of growth are of key importance for clinical symptoms and prognosis. At the same time, as research shows, they pose a serious threat to a patient's life, especially at an advanced stage of development. The type of therapy used depends on the anatomical location of the cancer, its type, and the degree of progression. One of the modern forms of therapy used to treat gastrointestinal cancers is PDT, which has been approved for the treatment of esophageal cancer in the United States. Despite the increasingly rapid clinical use of this treatment method, the exact immunological mechanisms it induces in cancer cells has not yet been fully elucidated. This article presents a review of the current understanding of the mode of action of photodynamic therapy on cells of various gastrointestinal cancers with an emphasis on colorectal cancer. The types of cell death induced by PDT include apoptosis, necrosis, and pyroptosis. Anticancer effects are also a result of the destruction of tumor vasculature and activation of the immune system. Many reports exist that concern the mechanism of apoptosis induction, of which the mitochondrial pathway is most often emphasized. Photodynamic therapy may also have a beneficial effect on such aspects of cancer as the ability to develop metastases or contribute to reducing resistance to known pharmacological agents.

Epigenomic reprogramming of therapy-resistant circulating tumor cells in colon cancer

Therapy resistance is a major challenge in colorectal cancer management. Epigenetic changes, such as DNA methylation, in tumor cells are involved in the development of acquired resistance during treatment. Here, we characterized the DNA methylation landscape of colon circulating tumor cells (CTCs) during cancer progression and therapy resistance development. To this aim, we used nine permanent CTC lines that were derived from peripheral blood samples of a patient with metastatic colon cancer collected before treatment initiation (CTC-MCC-41) and during treatment and cancer progression (CTC-MCC-41.4 and CTC-MCC-41.5 [A-G]). We analyzed the DNA methylome of these nine CTC lines using EPIC arrays and also assessed the association between DNA methylation and gene expression profiles. We confirmed DNA methylation and gene expression results by pyrosequencing and RT-qPCR, respectively. The global DNA methylation profiles were different in the pre-treatment CTC line and in CTC lines derived during therapy resistance development. These resistant CTC lines were characterized by a more hypomethylated profile compared with the pre-treatment CTC line. Most of the observed DNA methylation differences were localized at CpG-poor regions and some in CpG islands, shore regions and promoters. We identified a distinctive DNA methylation signature that clearly differentiated the pre-treatment CTC line from the others. Of note, the genes involved in this signature were associated with cancer-relevant pathways, including PI3K/AKT, MAPK, Wnt signaling and metabolism. We identified several epigenetically deregulated genes associated with therapy resistance in CTCs, such as AP2M1. Our results bring new knowledge on the epigenomic landscape of therapy-resistant CTCs, providing novel mechanisms of resistance as well as potential biomarkers and therapeutic targets for advanced CRC management.

CRISPR/Cas9: a powerful tool in colorectal cancer research

Colorectal cancer (CRC) is one of the most common malignant cancers worldwide and seriously threatens human health. The clustered regulatory interspaced short palindromic repeat/CRISPR-associate nuclease 9 (CRISPR/Cas9) system is an adaptive immune system of bacteria or archaea. Since its introduction, research into various aspects of treatment approaches for CRC has been accelerated, including investigation of the oncogenes, tumor suppressor genes (TSGs), drug resistance genes, target genes, mouse model construction, and especially in genome-wide library screening. Furthermore, the CRISPR/Cas9 system can be utilized for gene therapy for CRC, specifically involving in the molecular targeted drug delivery or targeted knockout in vivo. In this review, we elucidate the mechanism of the CRISPR/Cas9 system and its comprehensive applications in CRC. Additionally, we discussed the issue of off-target effects associated with CRISPR/Cas9, which serves to restrict its practical application. Future research on CRC should in-depth and systematically utilize the CRISPR/Cas9 system thereby achieving clinical practice.

Harnessing Ferroptosis to Overcome Drug Resistance in Colorectal Cancer: Promising Therapeutic Approaches

Drug resistance remains a significant challenge in the treatment of colorectal cancer (CRC). In recent years, the emerging field of ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation, has offered new insights and potential therapeutic strategies for overcoming drug resistance in CRC. This review examines the role of ferroptosis in CRC and its impact on drug resistance. It highlights the distinctive features and advantages of ferroptosis compared to other cell death pathways, such as apoptosis and necrosis. Furthermore, the review discusses current research advances in the field, including novel treatment approaches that target ferroptosis. These approaches involve the use of ferroptosis inducers, interventions in iron metabolism and lipid peroxidation, and combination therapies to enhance the efficacy of ferroptosis. The review also explores the potential of immunotherapy in modulating ferroptosis as a therapeutic strategy. Additionally, it evaluates the strengths and limitations of targeting ferroptosis, such as its selectivity, low side effects, and potential to overcome resistance, as well as challenges related to treatment specificity and drug development. Looking to the future, this review discusses the prospects of ferroptosis-based therapies in CRC, emphasizing the importance of further research to elucidate the interaction between ferroptosis and drug resistance. It proposes future directions for more effective treatment strategies, including the development of new therapeutic approaches, combination therapies, and integration with emerging fields such as precision medicine. In conclusion, harnessing ferroptosis represents a promising avenue for overcoming drug resistance in CRC. Continued research efforts in this field are crucial for optimizing therapeutic outcomes and providing hope for CRC patients.

Optimized silk fibroin nanoparticle functionalization with anti-CEA nanobody enhancing active targeting of colorectal cancer cells

This work aimed to establish a simple and feasible method to obtain silk fibroin nanoparticles (SFNPs) with uniform particles size, and then modify the SFNPs with nanobody (Nb) 11C12 targeting the proximal membrane end of carcinoembryonic antigen on the surface of colorectal cancer (CRC) cells. The regenerated silk fibroin (SF) was isolated using ultrafiltration tubes with a 50 kDa molecular weight cut-off, and the retention fraction (named as SF > 50 kDa) was further self-assembled into SFNPs by ethanol induction. Scanning electron microscope (SEM) and high-resolution transmission electron microscop showed that the SFNPs with uniform particles size were formed. Due to electrostatic adsorption and pH responsiveness, SFNPs have been proved to effectively load and release the anticancer drug doxorubicin hydrochloride (DOX) (DOX@SFNPs). Further, targeting molecule Nb 11C12 was used to modify these nanoparticles, constituting the targeted outer layer of the drug delivery system (DOX@SFNPs-11C12), achieving precise localization to cancer cells. The release amount of DOX observed fromin vitrodrug release profiles increased as follows: pH 7.4 < pH 6.8 < pH 5.4, demonstrating that the DOX release could be accelerated in a weakly acidic environment.In vitrocytotoxicity experiments displayed that SFNPs-11C12 nanoparticles exhibited good safety and biocompatibility. Drug-loaded nanoparticles, DOX@SFNPs-11C12, led to higher LoVo cells apoptosis compared to DOX@SFNPs. Fluorescence spectrophotometer characterization and confocal laser scanning microscopy further showed that the internalization of DOX was highest in the DOX@SFNPs-11C12, certifying that the introduced targeting molecule enhanced the uptake of drug delivery system by LoVo cells. This study provides a simple and operational approach to developing an optimized SFNPs drug delivery system modified by targeting Nb, which can be a good candidate for CRC therapy.

Delivery of Engineered Primary Tumor-Derived Exosomes Effectively Suppressed the Colorectal Cancer Chemoresistance and Liver Metastasis

Liver metastasis is one of the major causes of colorectal cancer (CRC)-related morbidity and mortality. Delivering small interfering RNAs (siRNAs) or noncoding RNAs has been reported as a promising method to target liver metastasis and chemoresistance in CRC. Here, we report a noncoding RNA delivery system using exosomes derived from primary patient cells. Coiled-coil domain-containing protein 80 (CCDC80) was strongly associated with CRC liver metastasis and chemoresistance, a finding validated by bioinformatic analysis and clinical specimens. Silencing CCDC80 significantly increased sensitivity to chemotherapy agents in OXA-resistant cell lines and a mouse model. The primary cell-derived exosome delivery system was designed to simultaneously deliver siRNAs targeting CCDC80 and increase chemotherapy sensitivity in the distant CRC liver metastasis mouse models and patient-derived xenograft mouse models. We further validated the antitumor effect in an ex vivo model of chemoresistant CRC organoids and a patient-derived organoid xenograft model. Tumor-bearing mice treated with the siRNA-delivering exosomes and hepatectomy showed ideal overall survival. Our results provide a therapeutic target and represent a possible therapeutic alternative for patients with CRC and distant metastasis and in cases of chemoresistance.

The 2022 Report on the Human Proteome from the HUPO Human Proteome Project

The 2022 Metrics of the Human Proteome from the HUPO Human Proteome Project (HPP) show that protein expression has now been credibly detected (neXtProt PE1 level) for 18 407 (93.2%) of the 19 750 predicted proteins coded in the human genome, a net gain of 50 since 2021 from data sets generated around the world and reanalyzed by the HPP. Conversely, the number of neXtProt PE2, PE3, and PE4 missing proteins has been reduced by 78 from 1421 to 1343. This represents continuing experimental progress on the human proteome parts list across all the chromosomes, as well as significant reclassifications. Meanwhile, applying proteomics in a vast array of biological and clinical studies continues to yield significant findings and growing integration with other omics platforms. We present highlights from the Chromosome-Centric HPP, Biology and Disease-driven HPP, and HPP Resource Pillars, compare features of mass spectrometry and Olink and Somalogic platforms, note the emergence of translation products from ribosome profiling of small open reading frames, and discuss the launch of the initial HPP Grand Challenge Project, "A Function for Each Protein".

Exosome-Transmitted miR-506-3p Inhibits Colorectal Cancer Cell Malignancy via Regulating GSTP1

Exosome-mediated microRNA transfer has been shown to regulate cancer progression. However, the involvement of exosomal-miR-506-3p in colorectal cancer (CRC) is unknown. The goal of the research was to study into the role of exosomal-miR-506-3p in CRC. Using a qRT-PCR experiment, it was observed that CRC tissues had lower levels of miR-506-3p than non-tumor tissues. It was observed that miR-506-3p inhibited the proliferation, regulates apoptosis, and cell cycle of HT29 and SW480 cells as compared to control groups. Dual luciferase reporter assay results showed that GSTP1 was the downstream target molecule of miR-506-3p, which was consistent with the database prediction. Furthermore, FHC cells transfected with miR-506-3p could transfer miR-506-3p to SW480 cells, limiting cell growth and inducing cell death. We discovered a unique regulatory mechanism in which exosome-mediated transfer of miR-506-3p reduces proliferation and induces apoptosis in CRC through negative regulation of GSTP1, implying that exosome-mediated delivery of miR-506-3p provides fresh insight into CRC diagnostics and treatment.

Nutlin-3 acts as a DNA methyltransferase inhibitor to sensitize esophageal cancer to chemoradiation

Esophageal squamous cell carcinoma (ESCC) is highly resistant to chemoradiation therapy. We aimed to examine whether Nutlin-3, a molecule that suppresses murine double min 2 (MDM2)-mediated p53 and Retinoblastoma (RB) protein degradation leading to downregulation of DNA methyltransferases (DNMTs), can be a novel therapeutic agent for ESCC. We used wild-type and chemoradiation-resistant ESCC cell lines in this study. The expression of DNMTs, p53 and RB, and methylation level of tumor suppressor genes (TSG) were analyzed upon Nutlin-3 treatment. The antitumor efficacy of Nutlin-3 was investigated in ESCC cell lines and xenograft tumor model. TSG protein expression was checked in the excised tumor tissue. Nutlin-3 induced upregulation of p53 and RB and downregulation of DNMTs proteins in the chemoradiation-resistant and aggressive ESCC cells. The methylation level of TSGs was decreased by Nutlin-3. Nutlin-3 inhibits clonogenic growth of ESCC cells and exerts a synergistic cytotoxic-effect when combined with chemotherapeutic agent cisplatin. Moreover, xenograft tumor growth in SCID mice was suppressed by Nutlin-3. The protein expression level of DNMTs was downregulated, and that of TSGs was upregulated by Nutlin-3 treatment in the excised tumor tissue. In conclusion, Nutlin-3 is a potential therapeutic agent that can potentiate the treatment efficacy of chemoradiation-resistant ESCC.

Hemoglobin Nanocrystals for Drugs Free, Synergistic Theranostics of Colon Tumor

The conventional approach in cancer nanomedicine involves advanced drug nanocarriers delivering preloaded therapeutics to targeted tumor sites to maximize drug efficiency. However, both cancer drugs and nanocarriers inevitably produce side effects and systemic toxicity. Herein, hemoglobin nanocrystals (HbC) as drug-free theranostic nanoformulations with the tumor microenvironment (TME) activated diagnostic and therapeutic abilities towards colon tumors are introduced. HbC can release Fe²⁺ oxidized to Fe³⁺ in the Fenton reaction with tumor endogenous H₂ O₂ , concurrently with the generation of cytotoxic hydroxyl radicals (•OH) that allow for chemodynamic therapy (CDT). Furthermore, in situ-produced Fe³⁺ reacts with colon tumor-abundant H₂ S, resulting in the production of Fe_{1- x} S, which provides magnetic resonance imaging (MRI) contrast and allows for NIR light-inducible photothermal therapy (PTT). In vitro and in vivo studies revealed that HbC produced CDT towards 4T1 tumors, and MRI-guided, synergistically enhanced combination of CDT and PTT against H₂ S abundant colon tumors (CT26), with negligible toxicity towards normal tissues, enlightening HbC as highly efficient and biocompatible TME activated theranostic nanoplatform specific against colon cancer without any traditional drugs and drug carriers.

The Role of microRNAs in Regulating Cancer Cell Response to Oxaliplatin-Containing Regimens

Oxaliplatin (cyclohexane-1,2-diamine; oxalate; platinum [2+]) is a third-generation chemotherapeutic drug with anticancer effects. Oxaliplatin has a role in the treatment of several cancers. It is one of the few drugs which can eliminate the neoplastic cells of colorectal cancer. Also, it has an influential role in breast cancer, lung cancer, bladder cancer, prostate cancer, and gastric cancer. Although oxaliplatin has many beneficial effects in cancer treatment, resistance to this drug is in the way to cure neoplastic cells and reduce treatment efficacy. microRNAs are a subtype of small noncoding RNAs with ∼22 nucleotides that exist among species. They have diverse roles in physiological processes, including cellular proliferation and cell death. Moreover, miRNAs have essential roles in resistance to cancer treatment and can strengthen sensitivity to chemotherapeutic drugs and regimens. In colorectal cancer, the co-treatment of oxaliplatin with anti-miR-19a can partially reverse the oxaliplatin resistance through the upregulation of phosphatase and tensin homolog (PTEN). Moreover, by preventing the spread of gastric cancer cells and downregulating glypican-3 (GPC3), MiR-4510 may modify immunosuppressive signals in the tumor microenvironment. Treatment with oxaliplatin may develop into a specialized therapeutic drug for patients with miR-4510 inhibition and glypican-3-expressing gastric cancer. Eventually, miR-122 upregulation or Wnt/β-catenin signaling suppression boosted the death of HCC cells and made them more sensitive to oxaliplatin. Herein, we have reviewed the role of microRNAs in regulating cancer cells' response to oxaliplatin, with particular attention to gastrointestinal cancers. We also discussed the role of these noncoding RNAs in the pathophysiology of oxaliplatin-induced neuropathic pain.

IKKα kinase silencing increases doxorubicin-induced apoptosis through regulation of oxidative DNA damage response in colon cancer cells

The inhibitor of kappa B kinase alpha (IKKα) is demonstrated to be involved in the various aspects of cancer biology, from its initiation, to progression, metastasis, and drug resistance. The aim of this study was to investigate the role of IKKα in doxorubicin (DOX)-mediated induction in apoptosis in SW-480 colon cancer cells. Cells were transfected with siRNA against IKKα and treated with DOX. MTT assay was applied to measure SW-480 cell proliferation. The mRNA levels of γ-H2AX within cells were assessed by qRT-PCR. 8-Hydroxy-2'-deoxyguanosine was measured by ELISA. The formation of intracellular reactive oxygen species (ROS) was detected by fluorometry. The antioxidant activities of some enzymes were also determined. For evaluation of apoptosis, ELISA assay was applied. IKKα silencing dramatically increased the doxorubicin cytotoxic effects. In addition, IKKα silencing substantially overexpressed γ-H2AX in SW-480 cells. Furthermore, upon IKKα silencing, the levels of ROS were elevated and the antioxidant defense system was significantly weakened. In addition, IKKα silencing led to the enhancement of apoptotic cells in doxorubicin-treated SW-480 cells. Co-treatment of IKKα and doxorubicin led to the enhanced cellular cytotoxicity via robosting ROS formation, inducing oxidative DNA damage, and decreasing cellular antioxidant defense, and finally potent apoptosis induction in cancer cell lines.

MicroRNAs (miRNAs): Novel potential therapeutic targets in colorectal cancer

Colorectal cancer (CRC) is the most common malignant tumor and one of the most lethal malignant tumors in the world. Despite treatment with a combination of surgery, radiotherapy, and/or systemic treatment, including chemotherapy and targeted therapy, the prognosis of patients with advanced CRC remains poor. Therefore, there is an urgent need to explore novel therapeutic strategies and targets for the treatment of CRC. MicroRNAs (miRNAs/miRs) are a class of short noncoding RNAs (approximately 22 nucleotides) involved in posttranscriptional gene expression regulation. The dysregulation of its expression is recognized as a key regulator related to the development, progression and metastasis of CRC. In recent years, a number of miRNAs have been identified as regulators of drug resistance in CRC, and some have gained attention as potential targets to overcome the drug resistance of CRC. In this review, we introduce the miRNAs and the diverse mechanisms of miRNAs in CRC and summarize the potential targeted therapies of CRC based on the miRNAs.

Nanoengineering a Zeolitic Imidazolate Framework-8 Capable of Manipulating Energy Metabolism against Cancer Chemo-Phototherapy Resistance

Chemo-phototherapy has emerged as a promising approach to complement traditional cancer treatment and enhance therapeutic effects. However, it still faces the challenges of drug efflux transporter-mediated chemoresistance and heat shock proteins (HSPs)-mediated phototherapy tolerance, which both depend on an excessive supply of adenosine triphosphate. Therefore, manipulating energy metabolism to impair the expression or function of P-glycoprotein (P-gp) and HSPs may be a prospective strategy to reverse cancer therapeutic resistance. Herein, a chondroitin sulfate (CS)-functionalized zeolitic imidazolate framework-8 (ZIF-8) chemo-phototherapy nanoplatform (CS/ZIF-8@A780/DOX NPs) is rationally designed that is capable of manipulating energy metabolism against cancer therapeutic resistance by integrating the photosensitizer IR780 iodide (IR780)-conjugated atovaquone (ATO) (A780) and the chemotherapeutic agent doxorubicin (DOX). Mechanistically, ATO and zinc ions that are released in the acidic tumor microenvironment can lead to systematic energy exhaustion through disturbing mitochondrial electron transport and the glycolysis process, thus suppressing the activity of P-gp and HSP70, respectively. In addition, CS is used on the surface of ZIF-8@A780/DOX NPs to improve the targeting capability to tumor tissues. These data provide an efficient strategy for manipulating energy metabolism for cancer treatment, especially for overcoming cancer chemo-phototherapy resistance.

Blockade of Nuclear β-Catenin Signaling via Direct Targeting of RanBP3 with NU2058 Induces Cell Senescence to Suppress Colorectal Tumorigenesis

Colorectal cancer (CRC) is one of the most common malignant tumors in the world, with high prevalence and low 5-year survival. Most of the CRC patients show excessive activation of the Wnt/β-catenin pathway which is a vital target for CRC treatment. Based on multiple CRC cell lines with different nuclear expression of β-catenin, NU2058 is identified from a small molecule library consisting of 280 bioactive compounds and found to selectively inhibit the proliferation of CRC cells with nuclear β-catenin activation in vitro and in vivo. The translational significance of NU2058 alone or in combination with chemotherapeutic drugs oxaliplatin and irinotecan (SN38) in CRC is demonstrated in orthotopic tumor model and patient-derived xenograft models. By integrating limited proteolysis-small molecule mapping (LiP-SMap) and mass spectrometry (MS), Ran-binding protein 3 (RanBP3) is identified as the direct target of NU2058. The results show that RanBP3 is a tumor suppressor in CRC and is associated with patient survival. Mechanistically, NU2058 increases the interaction of RanBP3 and β-catenin to promote nuclear export of β-catenin, which further inhibits transcription of c-Myc and cyclin D1 to induce cell senescence. Collectively, NU2058 may serve as a promising therapeutic agent for CRC patients with selective disruption of pathologic Wnt/β-catenin signaling.

ECM1 regulates the resistance of colorectal cancer to 5-FU treatment by modulating apoptotic cell death and epithelial-mesenchymal transition induction

5-Fluorouracil (5-FU) chemoresistance is a persistent impediment to the efficient treatment of many types of cancer, yet the molecular mechanisms underlying such resistance remain incompletely understood. Here we found CRC patients resistant to 5-FU treatment exhibited increased extracellular matrix protein 1 (ECM1) expression compared to CRC patients sensitive to this chemotherapeutic agent, and higher levels of ECM1 expression were correlated significantly with shorter overall survival and disease-free survival. 5-FU resistant HCT15 (HCT15/FU) cells expressed significantly higher levels of ECM1 relative to parental HCT15 cells. Changes in ECM1 expression altered the ability of both parental and HCT15/FU cells to tolerate the medication in vitro and in vivo via processes associated with apoptosis and EMT induction. From a mechanistic perspective, knocking down and overexpressing ECM1 in HCT15/FU and HCT15 cell lines inhibited and activated PI3K/AKT/GSK3β signaling, respectively. Accordingly, 5-FU-induced apoptotic activity and EMT phenotype changes were affected by treatment with PI3K/AKT agonists and inhibitors. Together, these data support a model wherein ECM1 regulates CRC resistance to 5-FU via PI3K/AKT/GSK3β pathway-mediated modulation of apoptotic resistance and EMT induction, highlighting ECM1 as a promising target for therapeutic intervention for efforts aimed at overcoming chemoresistance in CRC patients.

A serum metabolomics study based on LC-MS: Chemosensitization effects of Rauvolfia vomitoria Afzel. combined with 5- fluorouracil on colorectal cancer mice

Colorectal cancer (CRC) is one of the malignant tumors with high incidence, and is mainly treated by chemotherapy at present. However, during CRC treatment, long-term use of traditional chemotherapeutic drugs will reduce the sensitivity of chemotherapy. Our previous studies have shown that Rauvolfia vomitoria total alkaloids (RVA) played an important role in 5-fluorouracil (5-FU) chemosensitization in CRC therapy, but its intervention mechanism has not been clarified completely in the metabolic level. Therefore, in this study, LC-MS based metabolomics was employed to explore the mechanism of 5-FU chemosensitization in CRC induced by the combination of RVA and conventional chemotherapeutic with 5-FU. The results showed that the final tumor weight of the high-dose combined group was significantly different from that of the 5-FU alone group. To evaluate the chemosensitization effects of RVA, serum samples collected from six groups (six mice in each group) with different administration methods were analyzed by HPLC-Q-Exactive Orbitrap/MS. After multivariate statistical analysis and metabolites identification, 25 different metabolites were identified between the 5-FU treatment group and combined high-dose treatment group, among which lipid and fatty acid metabolism pathways were mostly affected. These results suggest that RVA may sensitize traditional chemotherapeutic drug 5-FU and exert anti-tumor activity through influencing lipid metabolism and cell energy metabolism. Metabolomics provided a new insight into estimate of the therapeutic effect and dissection of the potential mechanisms of traditional Chinese medicine in treating colorectal cancer.

Chemokines in progression, chemoresistance, diagnosis, and prognosis of colorectal cancer

Plenty of factors affect the oncogenesis and progression of colorectal cancer in the tumor microenvironment, including various immune cells, stromal cells, cytokines, and other factors. Chemokine is a member of the cytokine superfamily. It is an indispensable component in the tumor microenvironment. Chemokines play an antitumor or pro-tumor role by recruitment or polarization of recruiting immune cells. Meanwhile, chemokines, as signal molecules, participate in the formation of a cross talk among signaling pathways and non-coding RNAs, which may be involved in promoting tumor progression. In addition, they also function in immune escape. Chemokines are related to drug resistance of tumor cells and may even provide reference for the diagnosis, therapy, and prognosis of patients with colorectal cancer.

The Interaction Between Epigenetic Changes, EMT, and Exosomes in Predicting Metastasis of Colorectal Cancers (CRC)

Worldwide, colorectal cancer (CRC) ranks as the third most common malignancy, and the second most deadly with nearly one million attributable deaths in 2020. Metastatic disease is present in nearly 25% of newly diagnosed CRC, and despite advances in chemotherapy, less than 20% will remain alive at 5 years. Epigenetic change plays a key role in the epithelial-to-mesenchymal transition (EMT), which is a crucial phenotype for metastasis and mainly includes DNA methylation, non-coding RNAs (ncRNAs), and N6-methyladenosine (m6A) RNA, seemingly valuable biomarkers in CRCs. For ncRNAs, there exists a “molecular sponge effect” between long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs). The detection of exosomes is a novel method in CRC monitoring, especially for predicting metastasis. There is a close relationship between exosomes and EMT in CRCs. This review summarizes the close relationship between epigenetic changes and EMT in CRCs and emphasizes the crucial function of exosomes in regulating the EMT process.

Construction of a prognostic glycolysis-related lncRNA signature for patients with colorectal cancer

Aerobic glycolysis is a common metabolic phenotype in tumors that helps cancer cells adjust to severe living conditions and can aid metastasis in several types of carcinomas, including colorectal cancer (CRC). Long non-coding RNAs (lncRNAs) can influence tumor biology and have been previously used to assess patients' outcomes and to identify potential therapeutic targets. However, despite the importance of glycolysis-related lncRNAs (GRLs) in the development of CRC, studies on their use as prognostic markers are still limited. Herein, we applied a series of bioinformatic analyses to screen potential prognostic lncRNAs for colorectal cancer. Out of all lncRNAs screened, nine GRLs were selected to constitute a prognostic signature. Based on the signature, two molecular subtypes were classified with distinct prognostic outcomes and excellent diagnostic accuracy (The 1-, 3- and 5-year AUC are 0.756, 0.716, and 0.721, respectively). The prognostic value of this signature was further validated using another cohort. The enriched molecular pathways, immune infiltration, and mutation landscape were also significantly different between the two groups. The different drug sensitivity results between the two groups suggest a potential strategy for precise treatment. Furthermore, we confirmed that AFAP1-AS1 could regulate aerobic glycolysis and metastasis of CRC cells. Overall, we developed a glycolysis-related lncRNA (GRL) signature and suggested that this signature could offer a predictive value and identify potential therapeutic targets for cancer therapy.

The Emerging Roles and Therapeutic Implications of Epigenetic Modifications in Ovarian Cancer

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies globally. In spite of positive responses to initial therapy, the overall survival rates of OC patients remain poor due to the development of drug resistance and consequent cancer recurrence. Indeed, intensive studies have been conducted to unravel the molecular mechanisms underlying OC therapeutic resistance. Besides, emerging evidence suggests a crucial role for epigenetic modifications, namely, DNA methylation, histone modifications, and non-coding RNA regulation, in the drug resistance of OC. These epigenetic modifications contribute to chemoresistance through various mechanisms, namely, upregulating the expression of multidrug resistance proteins (MRPs), remodeling of the tumor microenvironment, and deregulated immune response. Therefore, an in-depth understanding of the role of epigenetic mechanisms in clinical therapeutic resistance may improve the outcome of OC patients. In this review, we will discuss the epigenetic regulation of OC drug resistance and propose the potential clinical implications of epigenetic therapies to prevent or reverse OC drug resistance, which may inspire novel treatment options by targeting resistance mechanisms for drug-resistant OC patients.