Resistant Colorectal Cancer Cells Research Articles

Mitotic Arrest Deficient 2 Like 1 Contributes to Colorectal Cancer Cell Migration, Invasion, and Oxaliplatin Resistance Through the Wnt/β-Catenin Pathway.

Colorectal cancer (CRC) is a highly prevalent malignancy, requiring chemotherapy for advanced stages of the disease. Previously, we found that mitotic arrest deficient 2 like 1 (MAD2L1) was upregulated and facilitated malignant proliferation in CRC. However, the association between MAD2L1 expression and tumor progression, as well as chemotherapy resistance in CRC, remains unclear. The progression capacities of CRC cells were assessed using transwell and wound healing assays, and the resistance to cisplatin in oxaliplatin-resistant CRC cells was assessed using CCK-8 assay and flow cytometry. Relevant protein levels of epithelial-to-mesenchymal transition (EMT) and Wnt/β-catenin pathway were analyzed using western blotting. Revealing the impact of MAD2L1 on metastasis and drug resistance in CRC through inhibition of the Wnt/β-catenin pathway. Knockdown of MAD2L1 attenuated the malignant progression of CRC cells, inhibited EMT, and blocked the Wnt/β-catenin pathway. MAD2L1 was significantly upregulated in oxaliplatin-resistant CRC cells, accompanied by the activation of the Wnt/β-catenin pathway. Knockdown of MAD2L1 effectively reversed oxaliplatin resistance, leading to apoptosis and downregulation of the protein expression levels of β-catenin, P-glycoprotein (P-gp), and ABCG2. After the knockdown of MAD2L1, the inhibition of the Wnt/β-catenin pathway exhibited a synergistic effect, effectively suppressing malignant progression and reversing oxaliplatin resistance in CRC cells. So, knockdown of MAD2L1 suppressed cell malignant progression, equally sensitized resistant CRC cells to oxaliplatin, potentially by blocking the activation of the Wnt/β-catenin pathway.

In vivo delivery of PBAE/ZIF-8 enhances the sensitivity of colorectal cancer to doxorubicin through sh-LncRNA ASB16-AS1.

The aim of this study is to investigate the impact of sh-LncRNA ASB16-AS1 on doxorubicin (DOX) resistance in colorectal cancer (CRC). First, an in vitro study was conducted to investigate the effects of LncRNA ASB16-AS1, miR-185-5p, and TEAD1 on drug resistance in CRC cells. Subsequently, utilizing nanotechnology, poly(beta amino esters) (PBAE)/zeolitic imidazolate framework-8 (ZIF-8)@sh-LncRNA ASB16-AS1 nanoparticles (PZSNP) were synthesized and characterized, evaluating their cellular toxicity and hemolytic activity. Finally, a mouse subcutaneous tumor model was established by subcutaneous injection of SW480/DOX cell suspension to investigate the impact of PZSNP on the tumor. Under DOX treatment, downregulation of LncRNA ASB16-AS1, overexpression of miR-185-5p, or downregulation of TEAD1 suppressed the viability and proliferation of drug-resistant CRC cells while promoting apoptosis. Conversely, overexpression of LncRNA ASB16-AS1, inhibition of miR-185-5p, or overexpression of TEAD1 enhanced the viability and proliferation of drug-resistant CRC cells while inhibiting apoptosis. The synthesized PZSNP exhibited a spherical shape with an average particle size of 123.6 nm, possessed positive charge, displayed good stability. It effectively encapsulated shRNA and displayed low cellular toxicity and hemolytic activity. Under DOX treatment, significant tumor necrosis was observed in the PZSNP group, and tumor growth was suppressed without causing weight loss. LncRNA ASB16-AS1, miR-185-5p, and TEAD1 are involved in regulating cell viability, proliferation, and apoptosis, contributing to drug resistance in CRC cells. sh-LncRNA ASB16-AS1 enhances the sensitivity of CRC cells to DOX during treatment, and in vivo delivery of PZSNP may serve as an effective strategy to overcome chemotherapy resistance in CRC.

DST regulates cisplatin resistance in colorectal cancer via PI3K/Akt pathway.

Dystonin (DST), a potential tumor suppressor gene, plays a crucial role in regulating cancer cell proliferation and resistance to chemotherapy. However, DST's specific role in colorectal cancer (CRC) has not been thoroughly investigated, and this study aims to elucidate its molecular role in modulating cisplatin (DDP) resistance in CRC. DST expression was analyzed in CRC tumors, DDP-resistant CRC tissues, paracancer tissues, and normal tissues. Lentiviral overexpression and shRNA knockdown were conducted in advanced CRC and DDP-resistant cell lines to assess cell viability, apoptosis, invasion, migration, proliferation, and angiogenesis. Xenograft mouse models studied DST's impact on CRC tumor growth and DDP resistance in vivo. DST expression was significantly reduced in CRC tumor and DDP-resistant CRC tissues compared to paracancer and normal tissues (P < .001). Upregulating DST inhibited CRC and DDP-resistant cell viability, proliferation, invasion, and migration while promoting apoptosis. DST overexpression also reduced angiogenesis and attenuated DDP-induced cytotoxicity in CRC cells. Mechanistically, DST upregulation suppressed DDP resistance in CRC cells via the PI3K/Akt signaling pathway. DST upregulation reduced CRC tumor growth and mitigated DDP resistance, in vivo. DST plays a crucial role in limiting CRC progression and overcoming DDP resistance, suggesting potential for targeted CRC therapies.

Identification of key lncRNAs associated with oxaliplatin resistance in colorectal cancer cells and isolated exosomes: From In-Silico prediction to In-Vitro validation.

One of the critical challenges in managing colorectal cancer (CRC) is the development of oxaliplatin (OXP) resistance. Long non-coding RNAs (lncRNAs) have a crucial role in CRC progression and chemotherapy resistance, with exosomal lncRNAs emerging as potential biomarkers. This study aimed to predict key lncRNAs involved in OXP-resistance using in-silico methods and validate them using RT-qPCR methods in CRC cells and their isolated exosomes. Two public datasets, GSE42387 and GSE119481, were downloaded from the GEO database to identify differentially expressed genes (DEGs) and miRNAs (DEmiRNAs) associated with OXP-resistance in the HCT116 cell line. The analysis of GSE42387 revealed 210 DEGs, and GSE119481 identified 73 DEmiRNAs. A protein-protein interaction (PPI) network analysis of the DEGs identified 133 interconnected genes, from which the top ten genes with the highest degree scores were selected. By intersecting predicted miRNAs targeting these genes with the DEmiRNAs, 38 common miRNAs were found. Subsequently, 224 lncRNAs targeting these common miRNAs were predicted. LncRNA-miRNA-mRNA network were constructed and the top five lncRNAs with the highest degree scores were identified. Analysis using the Kaplan-Meier plotter database revealed that the key lncRNAs NEAT1, OIP5-AS1, and MALAT1 are significantly associated with the overall survival of CRC patients. To validate these lncRNAs, OXP-resistant HCT116 sub-cell line (HCT116/OXR) was developed by exposing parental HCT116 cells to gradually increasing concentrations of OXP. Exosomes derived from both HCT116 and HCT116/OXR cells were isolated and characterized utilizing dynamic light scattering (DLS), transmission electron microscopy (TEM), and Western blotting. RT-qPCR confirmed elevated levels of NEAT1, OIP5-AS1, and MALAT1 in HCT116/OXR cells and their exosomes compared to parental HCT116 cells and their exosomes. This study concludes that NEAT1, OIP5-AS1, and MALAT1 are associated with the OXP-resistance in CRC. The high levels of these lncRNAs in exosomes of resistant cells suggest their involvement in intercellular communication and resistance propagation. This positioning makes them promising biomarkers for OXP-resistance in CRC.

Polo-like Kinase 1 Predicts Lymph Node Metastasis in Middle Eastern Colorectal Cancer Patients; Its Inhibition Reverses 5-Fu Resistance in Colorectal Cancer Cells.

Polo-like kinase 1 (PLK1) is a serine/threonine-protein kinase essential for regulating multiple stages of cell cycle progression in mammals. Aberrant regulation of PLK1 has been observed in numerous human cancers and is linked to poor prognoses. However, its role in the pathogenesis of colorectal cancer (CRC) in the Middle East remains unexplored. PLK1 overexpression was noted in 60.3% (693/1149) of CRC cases and was significantly associated with aggressive clinico-pathological parameters and p-ERK1/2 overexpression. Intriguingly, multivariate logistic regression analysis identified PLK1 as an independent predictor of lymph node metastasis. Our in vitro experiments demonstrated that CRC cells with high PLK1 levels were resistant to 5-Fu treatment, while those with low PLK1 expression were sensitive. To investigate PLK1's role in chemoresistance, we used the specific inhibitor volasertib, which effectively reversed 5-Fu resistance. Interestingly, forced PLK1 expression activated the CRAF-MEK-ERK signaling cascade, while its inhibition suppressed this cascade. PLK1 knockdown reduced epithelial-to-mesenchymal transition (EMT) progression and stem cell-like traits in 5-Fu-resistant cells, implicating PLK1 in EMT induction and stemness in CRC. Moreover, silencing ERK1/2 significantly mitigated chemoresistance, EMT, and stemness properties in CRC cell lines that express PLK1. Furthermore, the knockdown of Zeb1 attenuated EMT and stemness, suggesting a possible link between EMT activation and the maintenance of stemness in CRC. Our findings underscore the pivotal role of PLK1 in mediating chemoresistance and suggest that PLK1 inhibition may represent a potential therapeutic strategy for the management of aggressive colorectal cancer subtypes.

Fructose shields human colorectal cancer cells from hypoxia-induced necroptosis

Recent studies have shown that high dietary fructose intake enhances intestinal tumor growth in mice. Our previous work indicated that glucose enables hypoxic colorectal cancer (CRC) cells to resist receptor-interacting protein (RIP)-dependent necroptosis. Despite having the same chemical formula, glucose and fructose are absorbed through different transporters yet both can enter the glycolytic metabolic pathway. The excessive intake of dietary fructose, leading to its overflow into the colon, allows colonic cells to absorb fructose apically. This study explores the mechanisms behind apical fructose-mediated death resistance in CRC cells under hypoxic stress. Utilizing three CRC cell lines (Caco-2, HT29, and T84) under normoxic and hypoxic conditions with varying fructose concentrations, we assessed lactate dehydrogenase (LDH) activity, RIP1/3 complex formation (a necroptosis marker), and cell integrity. We investigated the role of fructose in glycolytic-mediated death resistance using glycolytic inhibitors iodoacetate (IA, a glycolytic inhibitor to glyceraldehyde 3-phosphate dehydrogenase), and UK5099 (UK, an inhibitor to mitochondrial pyruvate carrier). Our findings reveal that apical fructose prevents the hypoxia-induced RIP-dependent necroptosis in Caco-2 and HT29 cells. Fructose exposure under hypoxia also preserved epithelial integrity. IA, but not UK, blocked fructose-mediated glycolytic metabolite production and necrosis, indicating that anaerobic glycolytic metabolites facilitate death resistance. Notably, fructose treatment upregulated pyruvate kinase (PK)-M1 mRNA in hypoxic Caco-2 and HT29 cells, while PKM2 upregulation was exclusive to HT29 cells. In conclusion, apical fructose utilization through glycolysis effectively inhibits hypoxia-induced RIP-dependent necroptosis in CRC cells, shedding light on potential metabolic adaptation mechanisms in the tumor microenvironment and suggesting novel targets for therapeutic intervention.

LncRNA-HMG incites colorectal cancer cells to chemoresistance via repressing p53-mediated ferroptosis

Upon chemotherapy, excessive reactive oxygen species (ROS) often lead to the production of massive lipid peroxides in cancer cells and induce cell death, namely ferroptosis. The elimination of ROS is pivotal for tumor cells to escape from ferroptosis and acquire drug resistance. Nevertheless, the precise functions of long non-coding RNAs (lncRNAs) in ROS metabolism and tumor drug-resistance remain elusive. In this study, we identify LncRNA-HMG as a chemoresistance-related lncRNA in colorectal cancer (CRC) by high-throughput screening. Abnormally high expression of LncRNA-HMG predicts poorer prognosis in CRC patients. Concurrently, we found that LncRNA-HMG protects CRC cells from ferroptosis upon chemotherapy, thus enhancing drug resistance of CRC cells. LncRNA-HMG binds to p53 and facilitates MDM2-mediated degradation of p53. Decreased p53 induces upregulation of SLC7A11 and VKORC1L1, which contribute to increase the supply of reducing agents and eliminate excessive ROS. Consequently, CRC cells escape from ferroptosis and acquire chemoresistance. Importantly, inhibition of LncRNA-HMG by anti-sense oligo (ASO) dramatically sensitizes CRC cells to chemotherapy in patient-derived xenograft (PDX) model. LncRNA-HMG is also a transcriptional target of β-catenin/TCF and activated Wnt signals trigger the marked upregulation of LncRNA-HMG. Collectively, these findings demonstrate that LncRNA-HMG promotes CRC chemoresistance and might be a prognostic or therapeutic target for CRC.

Zinc finger protein 263 promotes colorectal cancer cell progression by activating STAT3 and enhancing chemoradiotherapy resistance

Zinc finger protein 263 (ZNF263) is frequently upregulated in various tumor types; however, its function and regulatory mechanism in colorectal cancer (CRC) have not yet been elucidated. In this study, the expression of ZNF263 was systematically examined using data from The Cancer Genome Atlas database and samples from patients with CRC. The results indicated that high expression of ZNF263 in CRC tissues is significantly associated with tumor grade, lymph node metastasis and disant metastasis. Additionally, overexpression of ZNF263 significantly promoted the proliferation, invasion, migration, and epithelial-mesenchymal transition of CRC cells, while also increasing signal transducer and activator of transcription 3 (STAT3) expression and mRNA stability. Conversely, knockdown of ZNF263 inhibited the malignant behavior of CRC cells and decreased STAT3 expression and mRNA stability. Further mechanism studies using chromatin immunoprecipitation (CHIP) and luciferase assays verified that ZNF263 directly binds to the STAT3 promoter. Rescue experiments demonstrated that the knockdown or overexpression of STAT3 could significantly reverse the effects of ZNF263 on CRC cells. Additionally, our study found that overexpression of ZNF263 enhanced the resistance of CRC cells to the chemoradiotherapy. In summary, this study not only elucidated the significant role of ZNF263 in CRC but also proposed novel approaches and methodologies for the diagnosis and treatment of this malignancy.

Navigating the labyrinth of long non-coding RNAs in colorectal cancer: From chemoresistance to autophagy

Long non-coding RNAs (lncRNAs), with transcript lengths exceeding 200 nucleotides and little or no protein-coding capacity, have been found to impact colorectal cancer (CRC) through various biological processes. LncRNA expression can regulate autophagy, which plays dual roles in the initiation and progression of cancers, including CRC. Abnormal expression of lncRNAs is associated with the emergence of chemoresistance. Moreover, it has been confirmed that targeting autophagy through lncRNA regulation could be a viable approach for combating chemoresistance. Two recent studies titled “Human β-defensin-1 affects the mammalian target of rapamycin pathway and autophagy in colon cancer cells through long non-coding RNA TCONS_00014506” and “Upregulated lncRNA PRNT promotes progression and oxaliplatin resistance of colorectal cancer cells by regulating HIPK2 transcription” revealed novel insights into lncRNAs associated with autophagy and oxaliplatin resistance in CRC, respectively. In this editorial, we particularly focus on the regulatory role of lncRNAs in CRC-related autophagy and chemoresistance since the regulation of chemotherapeutic sensitivity by intervening with the lncRNAs involved in the autophagy process has become a promising new approach for cancer treatment.

In-Silico and In-Vitro Investigation of Key Long Non-coding RNAs Involved in 5-Fluorouracil Resistance in Colorectal Cancer Cells: Analyses Highlighting NEAT1 and MALAT1 as Contributors.

Background Acquired resistance to 5-fluorouracil (5-FU) frequently results in chemotherapy failure and disease recurrence in advanced colorectal cancer (CRC) patients. Research has demonstrated that dysregulation of long non-coding RNAs (lncRNAs) mediates the development of chemotherapy resistance in cancerous cells. The present study aims to identify key lncRNAs associated with 5-FU resistance in CRC using bioinformatic and experimental validation approaches. Methods The Gene Expression Omnibus (GEO) dataset GSE119481, which contains miRNA expression profiles of the parental CRC HCT116 cell line (HCT116/P) and its in-vitro established 5-FU-resistant sub-cell line (HCT116/FUR), was downloaded. Firstly, differentially expressed microRNAs (DEmiRNAs) between the parental and 5-FU resistance cells were identified. LncRNAs and mRNAs were then predicted using online databases. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to uncover relevant biological mechanisms and pathways. Networks integrating lncRNAs, miRNAs, and mRNAs interactions were constructed, and topological analyses were used to identify key lncRNAs associated with 5-FU resistance. An in-vitro model of the HCT116/FUR sub-cell line was developed by exposing the HCT116/P cell line to increasing concentrations of 5-FU. Finally, real-time quantitative PCR (RT-qPCR) was performed on total RNA extracted from the HCT116/P cell line and the HCT116/FUR sub-cell line to validate the in-silico predictions of key lncRNAs. Results A total of 32 DEmiRNAs were identified. Enrichment analysis demonstrated that these DEmiRNAs were mainly enriched in several cancer hallmark pathways that regulate cell growth, cell cycle, cell survival, inflammation, immune response, and apoptosis. The predictive analysis identified 237 unique lncRNAs and 123 mRNAs interacting with these DEmiRNAs. The pathway analysis indicated that most of these predicted genes were enriched in the cellular response to starvation, protein polyubiquitination, chromatin remodeling, and negative regulation of gene expression. Topological analyses of the lncRNA-miRNA-mRNA network highlighted the nuclear enriched abundant transcript 1 (NEAT1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and Opa interacting protein 5 antisense RNA 1 (OIP5-AS1) as central lncRNAs. Experimental analysis by RT-qPCR confirmed that the expression levels of NEAT1 and MALAT1 were significantly increased in HCT116/FUR cells compared to HCT116/P cells. However, no significant difference was observed in the OIP5-AS1 expression level between the two cells. Conclusion Our findings specifically highlight MALAT1 and NEAT1 as significant contributors to 5-FU resistance in CRC. These lncRNAs are promising biomarkers for diagnosing and predicting outcomes in CRC.

Activation of p38 and JNK by ROS Contributes to Deoxybouvardin-Mediated Intrinsic Apoptosis in Oxaliplatin-Sensitive and -Resistant Colorectal Cancer Cells.

Colorectal cancer (CRC) remains a global health burden, accounting for almost a million deaths annually. Deoxybouvardin (DB), a non-ribosomal peptide originally isolated from Bouvardia ternifolia, has been reported to possess antitumor activity; however, the detailed mechanisms underlying this anticancer activity have not been elucidated. We investigated the anticancer activity of the cyclic hexapeptide, DB, in human CRC HCT116 cells. Cell viability, evaluated by MTT assay, revealed that DB suppressed the growth of both oxaliplatin (Ox)-resistant HCT116 cells (HCT116-OxR) and Ox-sensitive cells in a concentration- and time-dependent manner. Increased reactive oxygen species (ROS) generation was observed in DB-treated CRC cells, and it induced cell cycle arrest at the G2/M phase by regulating p21, p27, cyclin B1, and cdc2 levels. In addition, Western blot analysis revealed that DB activated the phosphorylation of JNK and p38 MAPK in CRC. Furthermore, mitochondrial membrane potential (MMP) was dysregulated by DB, resulting in cytochrome c release and activation of caspases. Taken together, DB exhibited anticancer activity against both Ox-sensitive and Ox-resistant CRC cells by targeting JNK and p38 MAPK, increasing cellular ROS levels, and disrupting MMP. Thus, DB is a potential therapeutic agent for the treatment of Ox-resistant CRC.

Identification of a Novel Protein Phosphatase 2A Activator, PPA24, as a Potential Therapeutic for FOLFOX-Resistant Colorectal Cancer.

A series of compounds were designed utilizing molecular modeling and fragment-based design based upon the known protein phosphatase 2A (PP2A) activators, NSC49L and iHAP1, and evaluated for their ability to inhibit the viability of colorectal cancer (CRC) and folinic acid, 5-fluorouracil, and oxaliplatin (FOLFOX)-resistant CRC cells. PPA24 (19a) was identified as the most cytotoxic compound with IC50 values in the range of 2.36-6.75 μM in CRC and FOLFOX-resistant CRC cell lines. It stimulated PP2A activity to a greater extent, displayed lower binding energies through molecular docking, and showed higher binding affinity through surface plasmon resonance for PP2A catalytic subunit α than the known PP2A activators. PPA24 dose-dependently induced apoptosis and oxidative stress, decreased the level of c-Myc expression, and synergistically potentiated cytotoxicity when combined with gemcitabine and cisplatin. Furthermore, a PPA24-encapsulated nanoformulation significantly inhibited the growth of CRC xenografts without systemic toxicities. Together, these results signify the potential of PPA24 as a novel PP2A activator and a prospective therapeutic for CRC and FOLFOX-resistant CRC.

MiR-135b-5p promotes cetuximab resistance in colorectal cancer by regulating FOXN3

ABSTRACT Despite advances in targeted therapies, primary and acquired resistance make the treatment of colorectal cancer (CRC) a pressing issue to be resolved. According to reports, the development of CRC is linked to miRNA dysregulation. Multiple studies have demonstrated that miR-135b-5p has an aberrant expression level between CRC tissues and adjacent tissues. However, it is unclear whether there is a correlation between miR-135b-5p and cetuximab (CTx) resistance in CRC. Use the GEO database to measure miR-135b-5p expression in CRC. Additionally, RT-qPCR was applied to ascertain the production level of miR-135b-5p in three human CRC cells and NCM460 cells. The capacity of cells to migrate and invade was examined utilizing the wound-healing and transwell assays, while the CCK-8 assay served for evaluating cell viability, as well as colony formation assays for proliferation. The expected target protein of miR-135b-5p in CRC cell cetuximab resistance has been investigated using western blot. Suppression of miR-135b-5p could increase the CTx sensitivity of CTx-resistant CRC cells, as manifested by the attenuation of proliferation, migration, and invasion ability. Mechanistic studies revealed miR-135b-5p regulates the epithelial-to-mesenchymal transition (EMT) process and Wnt/β-catenin signaling pathway through downgulating FOXN3. In short, knockdowning miR-135b-5p could increase FOXN3 expression in CRC cells, promote the EMT process, and simultaneously activate the Wnt/β-catenin signaling pathway to elevate CTx resistance in CRC cells.

TRIP13 Activates Glycolysis to Promote Cell Stemness and Strengthen Doxorubicin Resistance of Colorectal Cancer Cells.

Chemotherapy resistance is one of the main causes of clinical chemotherapy failure. Current cancer research explores the drug resistance mechanism and new therapeutic targets. This work aims to elucidate the mechanism of thyroid hormone receptor interactor 13 (TRIP13) affecting doxorubicin (DOX) resistance in colorectal cancer (CRC). Bioinformatics analyses were employed to clarify TRIP13 expression in CRC tissues and predict the correlation of the TRIP13 enrichment pathway with glycolysis-related genes and stemness index mRNAsi. Quantitative real-time polymerase chain reaction and western blot were adopted to analyze the expression of TRIP13 and glycolysis- related genes. Cell Counting Kit-8 was utilized to determine the cell viability and IC50 value. Western blot was employed to measure the expression of stemness-related factors. Cell function assays were performed to detect cells' sphere-forming ability and glycolysis level. Animal models were constructed to determine the effects of TRIP13 expression on CRC tumor growth. TRIP13 was significantly overexpressed in CRC, concentrated in the glycolysis signaling pathway, and positively correlated with stemness index mRNAsi. High expression of TRIP13 facilitated DOX resistance in CRC. Further mechanistic studies revealed that overexpression of TRIP13 could promote cell stemness through glycolysis, which was also confirmed in animal experiments. TRIP13 was highly expressed in CRC, which enhanced the DOX resistance of CRC cells by activating glycolysis to promote cell stemness. These findings offer new insights into the pathogenesis of DOX resistance in CRC and suggest that TRIP13 may be a new target for reversing DOX resistance in CRC.

Cyclopeptide RA-V from Rubia yunnanensis restores activity of Adagrasib against colorectal cancer by reducing the expression of Nrf2

Adagrasib (MRTX849), an approved and promising KRAS G12C inhibitor, has shown the promising results for treating patients with advanced non-small cell lung cancer (NSCLC) or colorectal cancer (CRC) harboring KRAS-activating mutations. However, emergence of the acquired resistance limits its long-term efficacy and clinical application. Further understanding of the mechanism of the acquired resistance is crucial for developing more new effective therapeutic strategies. Herein, we firstly found a new connection between the acquired resistance to MRTX849 and nuclear factor erythroid 2-related factor 2 (Nrf2). The expression levels of Nrf2 and GLS1 proteins were substantially elevated in different CRC cell lines with the acquired resistance to MRTX849 in comparison with their corresponding parental cell lines. Next, we discovered that RA-V, one of natural cyclopeptides isolated from the roots of Rubia yunnanensis, could restore the response of resistant CRC cells to MRTX849. The results of molecular mechanisms showed that RA-V suppressed Nrf2 protein through the ubiquitin-proteasome-dependent degradation, leading to the induction of oxidative and ER stress, and DNA damage in CRC cell lines. Consequently, RA-V reverses the resistance to MRTX849 by inhibiting the Nrf2/GLS1 axis, which shows the potential for further developing into one of novel adjuvant therapies of MRTX849.

UL3 Regulates Redox Metabolism and Ferroptosis Sensitivity of p53-Deleted Colorectal Cancer Cells.

Despite advancements in therapeutic strategies, the development of drug resistance and metastasis remains a serious concern for the efficacy of chemotherapy against colorectal cancer (CRC). We have previously demonstrated that low expression of ribosomal protein uL3 positively correlates with chemoresistance in CRC patients. Here, we demonstrated that the loss of uL3 increased the metastatic capacity of CRC cells in chick embryos. Metabolomic analysis revealed large perturbations in amino acid and glutathione metabolism in resistant uL3-silenced CRC cells, indicating that uL3 silencing dramatically triggered redox metabolic reprogramming. RNA-Seq data revealed a notable dysregulation of 108 genes related to ferroptosis in CRC patients. Solute Carrier Family 7 Member 11 (SLC7A11) is one of the most dysregulated genes; its mRNA stability is negatively regulated by uL3, and its expression is inversely correlated with uL3 levels. Inhibition of SLC7A11 with erastin impaired resistant uL3-silenced CRC cell survival by inducing ferroptosis. Of interest, the combined treatment erastin plus uL3 enhanced the chemotherapeutic sensitivity of uL3-silenced CRC cells to erastin. The antimetastatic potential of the combined strategy was evaluated in chick embryos. Overall, our study sheds light on uL3-mediated chemoresistance and provides evidence of a novel therapeutic approach, erastin plus uL3, to induce ferroptosis, establishing individualized therapy by examining p53, uL3 and SLC7A11 profiles in tumors.

Caffeic Acid Enhances Anticancer Drug-induced Apoptosis in Acid-adapted HCT116 Colon Cancer Cells.

Apoptosis resistance in cancer cells adapted to acidic microenvironments poses a challenge for effective treatment. This study investigated the potential use of caffeic acid as an adjunct therapy to overcome drug resistance in colorectal cancer cells under acidic conditions. Long-term exposure to low-pH conditions induced resistance in HCT116 colorectal cancer cells. The effects of caffeic acid on proliferation, clonogenicity, and apoptosis induction were assessed alone and in combination with oxaliplatin and 5-Fluorouracil. The signaling pathways involved in drug resistance were examined by assessing the activities of PI3K/Akt and ERK1/2. Caffeic acid inhibited the proliferation and clonogenicity of acid-adapted cancer cells, and enhanced apoptosis when combined with anticancer drugs. Mechanistically, caffeic acid attenuated the hyperactivation of the PI3K/Akt and ERK1/2 signaling pathways associated with drug resistance. Caffeic acid is a promising therapeutic agent for targeting resistant cancer cells in acidic microenvironments. Its ability to inhibit proliferation, sensitize cells to apoptosis, and modulate signaling pathways highlights its potential for overcoming drug resistance in cancer therapy.

4-O-Methylascochlorin Synergistically Enhances 5-Fluorouracil-Induced Apoptosis by Inhibiting the Wnt/β-Catenin Signaling Pathway in Colorectal Cancer Cells.

4-O-Methyl-ascochlorin (MAC), a derivative of the prenyl-phenol antibiotic ascochlorin extracted from the fungus Ascochyta viciae, shows anticarcinogenic effects on various cancer cells. 5-Fluorouracil (5-FU) is used to treat colorectal cancer (CRC); however, its efficacy must be enhanced. In this study, we investigated the molecular mechanisms by which MAC acts synergistically with 5-FU to inhibit cell proliferation and induce apoptosis in CRC cells. MAC enhanced the cytotoxic effects of 5-FU by suppressing the Akt/mTOR/p70S6K and Wnt/β-catenin signaling pathways. It also reduced the viability of 5-FU-resistant (5-FU-R) cells. Furthermore, expression of anti-apoptosis-related proteins and cancer stem-like cell (CSC) markers by 5-FU-R cells decreased in response to MAC. Similar to MAC, the knockdown of CTNNB1 induced apoptosis and reduced expression of mRNA encoding CRC markers in 5-FU-R cells. In summary, these results suggest that MAC and other β-catenin modulators may be useful in overcoming the 5-FU resistance of CRC cells.

Fe-MOF nanoplatform: Specifically overcoming oxaliplatin resistance in colorectal cancer through multifaceted pathways

Oxaliplatin (OXA) is a widely used chemotherapy drug for advanced colorectal cancer (CRC), yet resistance frequently and rapidly develops in patients. Here, we explored a Fe-based metal-organic framework (Fe-MOF) as a nanoplatform to simultaneously deliver OXA and a nitric oxide (NO) donor, specifically l-Arginine (L-Arg). The aim was to overcome OXA resistance in CRC cells, thereby enhancing the anticancer efficacy against drug-resistant CRC. Due to the abundant glutathione (GSH) in tumor tissue, Fe3+ in Fe-MOF undergoes reduction to Fe2+, causing the collapse of Fe-MOF structure and the subsequent release of OXA and L-Arg. This process is accompanied by GSH depletion, amplifying the effectiveness of OXA against drug-resistant CRC. Fe2+ further reacts with overexpressed H2O2 to generate •OH, inducing direct cell apoptosis and subsequently reacting with L-Arg to rapidly produce NO. NO plays multifaceted roles in the anti-CRC effect, reversing drug resistance in CRC cells through multiple pathways, inducing apoptosis of CRC cells to initiate gas therapy, and reacting with •OH to generate highly toxic reactive nitrogen species for cancer cell destruction. This synergistic strategy effectively addresses the challenge of drug resistance in CRC, offering a promising avenue for enhancing the clinical effectiveness of OXA in cases resistant to conventional treatment.

Molecular mechanism of MLCK1 inducing 5-Fu resistance in colorectal cancer cells through activation of TNFR2/NF-κB pathway

Background and aimsChemotherapy resistance in colorectal cancer have been faced with significant challenges in recent years. Particular interest is directed to tumor microenvironment function. Recent work has, identified a small molecule named Divertin that prevents myosin light chain kinase 1(MLCK1) recruitment to the perijunctional actomyosin ring(PAMR), restores barrier function after tumor necrosis factor(TNF)-induced barrier loss and prevents disease progression in experimental inflammatory bowel disease. Studies have shown that MLCK is a potential target for affecting intestinal barrier function, as well as for tumor therapy. However, the relative contributions of MLCK expression and chemotherapy resistance in colorectal cancers have not been defined.MethodsStatistical analysis of MYLK gene expression differences in colorectal cancer patients and normal population and prognosis results from The Cancer Genome Atlas(TCGA) data. Cell activity was detected by Cell counting Kit-8. Cell proliferation was detected by monoclonal plate. The apoptosis was detected by flow cytometry and western blot. Determine the role of MLCK1 in inducing 5-Fluorouracil(5-Fu) resistance in colorectal cancer cells was detected by overexpression of MLCK1 and knock-down expression of MLCK1.ResultsMLCK1 is expressed at different levels in different colorectal cancer cells, high MLCK1 expressing cell lines are less sensitive to 5-Fu, and low MLCK1 expressing cell lines are more sensitive to 5-Fu. MLCK1 high expression enhances resistance to 5-Fu in colorectal cancer cells and the sensitivity to 5-Fu was increased after knocking down the expression of MLCK1, that might be closely correlated to TNFR2/NF-κB pathway.ConclusionsMLCK1 high expression can enhance resistance to 5-Fu in colorectal cancer cells and the sensitivity to 5-Fu was increased after knocking down the expression of MLCK1, that might be closely correlated to TNFR2/NF-κB pathway, which will provide a new method for the treatment of colorectal cancer patients who are resistant to 5-Fu chemotherapy.