Colorectal Cancer Cells Research Articles

The Anticancer Poperties of Diosgenin on Colorectal Cancer Cells Induced by Wnt/Β Catenin Signaling Pathway

Background: Colorectal cancer (CC) is one of the most prevalent cancers globally. Due to the severe side effects and the development of drug resistance in CC treatments, current therapeutic strategies often prove ineffective. As a result, there is a growing interest in exploring traditional medicinal plants as alternative treatment options for various human diseases. Diosgenin, a bioactive compound derived from plants, has shown potential in inhibiting the growth of human CC cells. The Wnt/β-catenin signaling pathway plays a critical role in colorectal tumorigenesis. Objectives: This study investigates the effects of Diosgenin on the Wnt/β-catenin pathway in CC cells. Methods: Colorectal cancer cells were treated with Diosgenin, and cell viability and plasma membrane integrity were assessed using the MTT assay and lactate dehydrogenase (LDH) activity assay, respectively. Apoptosis was evaluated through Annexin V/PI staining. The expression of Wnt/β-catenin-related genes was analyzed by quantitative PCR (qPCR). Results: Diosgenin significantly inhibited CC cell viability in a time- and concentration-dependent manner after 24, 48, 72, and 96 hours of exposure (P < 0.05). The IC50 values were determined to be 203.55, 122.95, 70.11, and 7.34 µM at 24, 48, 72, and 96 hours, respectively. Diosgenin at its IC50 concentration induced a significant increase in cell apoptosis after 24 hours of treatment (P < 0.05). Additionally, it caused a significant reduction in the expression of β-catenin, cyclin D1, and Pin1 (βCP). Conclusions: Diosgenin exhibits anti-CC effects by inhibiting the expression of βCP genes involved in the Wnt/β-catenin pathway, suggesting its potential as a therapeutic agent for CC.

Ethoxy-erianin phosphate inhibits angiogenesis in colorectal cancer by regulating the TMPO-AS1/miR-126-3p/PIK3R2 axis and inactivating the PI3k/AKT signaling pathway

Colorectal cancer (CRC) is the third most common malignancy, with increasing prevalence and mortality. How the ethoxy-erianin phosphate (EBTP) mediates CRC development remains unclear. Therefore, the current study evaluated the effects of EBTP on the proliferation, migration, and angiogenesis of CRC cells using CCK-8, Wound-healing, Transwell, and Tube formation assays. RNA sequencing and molecular docking techniques helped predict that EBTP could inhibit angiogenesis by regulating PIK3R2 expression while clarifying the mechanism behind EBTP-mediated CRC angiogenesis. Subsequently, several in vitro experiments indicated that PIK3R2 overexpression significantly improved the proliferation, migration, and angiogenesis of CRC cells while knocking down PIK3R2 expression inhibited their proliferation, migration, and angiogenesis. Simultaneously, PIK3R2 expression in CRC cells gradually decreased with increased EBTP concentration and action duration. Moreover, PIK3R2 overexpression in CRC cells could reverse the inhibitory EBTP effect in angiogenesis. Mouse experiments also depicted that EBTP inhibited CRC angiogenesis by down-regulating PIK3R2 expression. In addition, EBTP could inhibit PI3K/AKT pathway activity and indirectly control PIK3R2 expression through the lncRNA TMPO-AS1/miR-126-3p axis. Our findings highlighted that EBTP could inhibit CRC angiogenesis using the TMPO-AS1/miR-126-3p/PIK3R2/PI3k/AKT axis, providing a novel strategy for anti-angiogenic therapy in CRC.

Mitochondrial disruption resulting from Cepharanthine-mediated TOM inhibition triggers ferroptosis in colorectal cancer cells

BackgroundChemotherapy for colorectal cancer (CRC) urgently needs low-toxicity and highly effective phytomedicine. Cepharanthine (Cep) shown to have multiple anti-tumor effects, including colorectal cancer, whose pivotal mechanisms are not fully understood. Herein, the present work aims to reveal the impact of Cep on the mitochondrial and anti-injury functions of CRC cells.MethodsThe TOM70/20 expression was screened by bioinformatic databases. SW480 cells were utilized as the colorectal cancer cell model. The expression of TOM70/20 and the downstream molecules were measured by western blots (WB). The ferroptosis was analyzed using Transmission electron microscopy (TEM), C11-BODIPY, PGSK, and DCFH-DA probes, wherein the detection was performed by flow cytometry and laser confocal microscopy. The anti-cancer efficacy was conducted by CCK-8 and Annexin-V/PI assay. The rescue experiments were carried out using Fer-1 and TOM70 plasmid transfection.ResultsBioinformatic data identified TOM20 and TOM70 were highly expressed in colorectal cancer, which could be down-regulated by Cep. Further findings disclosed that Cep treatment destroyed the mitochondria and inactivated the NRF2 signaling pathway, an essential pathway for resistance to ferroptosis, thereby promoting reactive oxygen species (ROS) generation in CRC cells. As a result, prominent ferroptosis could be observed in CRC cells in response to Cep, which thereby led to the reduced cell viability of cancer cells. On the contrary, recovery of TOM70 dampened the Cep-elicited mitochondria damage, ferroptosis, and anti-cancer efficacy.ConclusionIn summary, Cep-mediated TOM inhibition inactivates the NRF2 signaling pathway, thereby triggering ferroptosis and achieving an anti-colorectal cancer effect. The current study provides an innovative chemotherapeutic approach for colorectal cancer with phytomedicine.

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.

Lower expressions of MIR34A and MIR31 in colo-rectal cancer are associated with an enriched immune microenvironment

IntroductionMicroRNAs (MIRs) play a crucial role in colorectal cancer (CRC) development and metastasis by regulating immune responses. Tumour-infiltrating lymphocytes (TILs) are an important predictive factor in many cancers, but, their association with microRNAs have not been studied well in colorectal cancer. Three microRNAs (MIR34A, MIR31 & MIR21), the roles of which in tumorigenesis is well-studied and which also possess immunomodulatory effect, were identified by extensive literature search. Of these, MIR34A acts as a tumour suppressor, MIR21 is considered an onco-MIR, and MIR31 displays both tumour-suppressing and oncogenic properties, making it ambiguous. This study examines the relationship between these three micro-RNAs and TILs in CRC. Materials & methodsConducted over 18 months at a tertiary cancer care hospital in southern India, this unicentric observational study included 69 cases. These cases were analyzed for miR expression using q-RT-PCR, TILs density through hematoxylin & eosin(H&E) slide examination, and p53 and beta-catenin expression via immunohistochemistry (IHC). Correlations between non-parametric variables were assessed using Chi-square and Spearman correlation tests. ResultsThe study found significantly higher MIR34A expression in patients aged 60 years and less (26/41, p=0.024) and a higher prevalence of MIR21 in male patients (23/35, p=0.012). TILs at the tumour advancing front were categorized as low (≤10 %) or high (≥15 %). Among the 36 cases with low TILs, high MIR34A and high MIR31 expressions were observed in 24 cases (p=0.016) and 23 cases (p=0.03), respectively. Conversely, 21 of 33 cases with high TILs had low expressions of both MIR34A and MIR31. High TILs were more common in early-stage CRC (TNM stages I-IIIA), with 20 out of 28 cases, compared to 28 of 41 cases in later stages (IIIB-IVC) exhibiting low TILs (p=0.003). Aberrant p53 expression correlated with lower MIR34A levels, consistent with TCGA data. ConclusionLower MIR34A and MIR31 levels are associated with higher TILs density in CRC. Unlike other cancers where MIR34A has anti-tumour effects, there was no statistically significant correlation between its expression and the pT or TNM stages in this study. Increased TILs being a good prognostic indicator, this suggests MIR34A and MIR31 may help CRC cells evade immune surveillance. Aberrant p53 expression downregulates MIR34A, underscoring the therapeutic potential of miRs.

PIWIL1 is recruited to centrosomes during mitosis in colorectal cancer cells and is linked to cell cycle progression

PIWI proteins, traditionally associated with germline development, have recently gained attention for their expression in various cancers, including colorectal cancer. However, the molecular mechanisms underlying their reactivation and impact on cancer initiation and progression remain elusive. Here, we found that PIWIL1 is expressed at relatively high levels in CRC-derived samples and cell lines, where it undergoes a dynamic relocalization to the centrosome during mitosis. Knockdown of PIWIL1 induces G2/M arrest associated with disruption of the mitotic spindle and aberrant metaphase events, highlighting its role in cell cycle progression. We also found that the expression of PIWIL1 is lost during the differentiation of Caco-2 cells into enterocytes and that PIWIL1 is expressed in cells at the base of the intestinal crypts in normal human colon tissue, where intestinal stem cells are known to reside. Thus, it is possible that the presence of PIWIL1 in cancer cells reflects a physiological role of this protein in stem cell maintenance, which would argue in favor of the proposed stem cell origin of CRC. Supporting this view, dedifferentiation of human fibroblasts into induced pluripotent stem cells (iPSCs) involves the reactivation of PIWIL2 expression, another member of the PIWI protein family. Overall, our findings suggest a role of PIWIL1 in mediating cell cycle dynamics, both in colorectal cancer cells and possibly also in intestinal stem cells. In a broader aspect, we provide evidence supporting an involvement of PIWI proteins in somatic stem cell maintenance, thus expanding the known non-gonadal functions of this protein family.

A polysaccharide with a triple helix structure from Agaricus bisporus: Characterization and anti-colon cancer activity

In this study, A polysaccharide WAAP-2 (121 kDa) with a triple-helical structure was isolated and purified from Agaricus bisporus for the first time. The physicochemical properties, structural characteristics and anti-colon cancer activity were preliminarily investigated. The primary structure indicated that WAAP-2 was composed of mannose, glucose and galactose and determined the position of the linkage between monosaccharide residues. The advanced structure revealed that WAAP-2 has a triple helix and tangled chain conformation. In the anti-colon cancer activity investigation, WAAP-2 exerted an apoptosis-inducing effect by causing HT-29 cell cycle arrest in S phase. WAAP-2 promoted HT-29 cell apoptosis by up-regulating the expression of Caspase-3 and Bax proteins while down-regulating the expression of Bcl-2 protein. Besides, WAAP-2 could inhibit the migration and invasion of colorectal cancer cells by inducing E-cadherin expression and inhibiting Vimentin expression to affect epithelial mesenchymal transition. This paper is of importance for the application of WAAP-2, a triple-helical structural polysaccharide from Agaricus bisporus, to low-toxicity anti-colon cancer drugs.

Protective Effects of Astaxanthin against Oxidative Stress: Attenuation of TNF-α-Induced Oxidative Damage in SW480 Cells and Azoxymethane/Dextran Sulfate Sodium-Induced Colitis-Associated Cancer in C57BL/6 Mice.

In this study, we investigated the protective effects of astaxanthin (AST) against oxidative stress induced by the combination of azoxymethane (AOM) and dextran sulfate sodium (DSS) in colitis-associated cancer (CAC) and TNF-α-induced human colorectal cancer cells (SW480), as well as the underlying mechanism. In vitro experiments revealed that astaxanthin reduced reactive oxygen species (ROS) generation and inhibited the expression of Phosphorylated JNK (P-JNK), Phosphorylated ERK (P-ERK), Phosphorylated p65 (P-p65), and the NF-κB downstream protein cyclooxygenase-2 (COX-2). In vivo experiments showed that astaxanthin ameliorated AOM/DSS-induced weight loss, shortened the colon length, and caused histomorphological changes. In addition, astaxanthin suppressed cellular inflammation by modulating the MAPK and NF-κB pathways and inhibiting the expression of the proinflammatory cytokines IL-6, IL-1β, and TNF-α. In conclusion, astaxanthin attenuates cellular inflammation and CAC through its antioxidant effects.

Humanized recombinant immunotoxin targeting hCG demonstrates therapeutic potential for advanced stage difficult to treat cancers

We report the development of an immunotherapeutic molecule, a Humanized immunotoxin, for treating hCG-expressing advanced-stage cancers. PiPP, a high-affinity anti-hCG monoclonal antibody, is used in the immunotoxin for ‘homing’ hCG-positive cancer cells. The deimmunized (DI) form of α-Sarcin, a fungal-origin toxin that lacks functional T-cell epitopes, is used in the design to ensure minimal immunogenicity of the immunotoxin for repetitive use in humans. A single-chain variable fragment (scFv) of PiPP was constructed by linking the Humanized VH and VL regions of the antibody. The scFv part of the antibody was further linked to the toxin α-Sarcin (DI) at the gene level and expressed as a recombinant protein in E. coli. The immunotoxin was purified from the bacterial cell lysate and analysed for binding and cytotoxicity to hCG-secreting colorectal and pancreatic cancer cells. The results showed that the scFv(PiPP)-Sarcin immunotoxin was able to bind to colorectal and pancreatic cancer cells and killed approximately 85% of the cells. In vivo testing of the immunotoxin produced results similar to those of in vitro testing against colorectal adenocarcinoma-induced tumours. This immunotoxin could be a promising immunotherapeutic agent for treating colorectal, pancreatic and other terminal-stage hCG-expressing cancers.

Anti-tumor activity of camptothecin analog conjugate of a RSPO4-based peptibody targeting LGR4/5/6 in preclinical models of colorectal cancer.

Antibody-drug conjugates (ADCs) have emerged as a major modality of targeted cancer therapy, yet no ADC has been approved for colorectal cancer (CRC). LGR4/5/6 (leucine-rich repeat containing, G protein-coupled receptor 4, 5, 6) are three related receptors that are expressed at high levels together or alternately in nearly all cases of CRC. ADCs targeting LGR5 have been shown to have robust anti-tumor potency, but not all CRC cells express LGR5 and LGR5-positive tumor cells may lose LGR5 expression due to cancer cell plasticity. R-spondin 4 (RSPO4) is a natural protein ligand of LGR4/5/6 with high affinity for all three receptors. We fused a mutant form of RSPO4 that retains high affinity binding to LGR4/5/6 to IgG1 Fc to create a peptibody designated R462. Conjugation of R462 with a camptothecin analog (CPT2) at eight drugs per peptibody led to the synthesis of R462-CPT2 that showed highly potent cytotoxic activity in vitro in CRC cell lines expressing any of LG4/5/6. In cell line xenograft and PDX models of CRC, R462-CPT2 demonstrated robust anti-tumor effect. Importantly, R462-CPT2 showed no major adverse effect at therapeutically effective dose levels. These results strongly support the use of RSPO ligand drug-conjugates that target LGR4/5/6 simultaneously for the treatment of CRC.

Hsa_circ_0007718 facilitates the progression of colorectal cancer by regulating the miR-1299/PSMC2 axis

Colorectal cancer (CRC) represents one of the most prevalent forms of malignant tumors, characterized by a notably high rate of mortality among affected individuals. The primary objective of this investigation is to delve into the functional role of Hsa_circ_0007718 in the context of colorectal cancer and to elucidate its impact on the progression of CRC by modulating the interaction between the miR-1299 microRNA and its target gene, PSMC2. To assess the expression levels of Hsa_circ_0007718, along with miR-1299 and PSMC2, real-time quantitative fluorescent PCR (qRT-PCR) assays were meticulously performed using both CRC cell lines and clinical samples derived from patients. A cellular model was established to investigate the interactions occurring between miR-1299 and Hsa_circ_0007718, as well as the connections to PSMC2, thereby providing a comprehensive understanding of these molecular interactions. The findings of this research revealed a significant upregulation of Hsa_circ_0007718 in both colorectal cancer cell lines and tissue samples. Importantly, the data indicated that the suppression of Hsa_circ_0007718 led to a marked decrease in the proliferation rates, migratory potential, and invasive capabilities of CRC cells. Furthermore, the study confirmed that Hsa_circ_0007718 acts as a downstream target of miR-1299, exerting its regulatory effects by inhibiting miR-1299 and thereby promoting the expression of PSMC2.

Synthetic Peptides Induce Human Colorectal Cancer Cell Death via Proapoptotic Pathways.

Cancer resistance to drugs and chemotherapy is a problem faced by public health systems worldwide. Repositioning antimicrobial peptides could be an efficient strategy to overcome that problem. This study aimed at repurposing antimicrobial peptides PepGAT and PepKAA for cancer treatment. After screening against several cancers, PepGAT and PepKAA presented IC50 values of 125.42 and 40.51 μM at 72 h toward colorectal cancer (CRC) cells. The mechanisms of action revealed that both peptides induced cell cycle arrest in G2/M and drove HCT-116 cells to death by triggering apoptosis. qPCR analysis revealed that peptides modulated gene expression in apoptosis, corroborating the data from caspase 3/7 and flow cytometry experiments. Yet, peptides induced ROS overaccumulation and increased membrane permeabilization, pore formation, and loss of internal content, leading to death. Additionally, peptides were able to inhibit cell invasion. Previous studies from the same group attested to no toxicity to normal human cells. Thus, PepGAT and PepKAA have great potential as anticancer molecules.

GLTSCR1 deficiency promotes colorectal cancer development through regulating non-homologous end joining.

Non-homologous end joining (NHEJ), as one major pathway of DNA double-strand break (DSB) repair, could cause genomic instability, which plays pivotal roles in cancer development. While, chromatin remodeling complexes dictate the selection and orchestration of DSB repair pathways by regulating chromatin dynamics. However, the crosstalk between NHEJ and chromatin remodeling in cancer progress remains unclear. In this study, deficiency of GLTSCR1 causes resistance to DNA damage in colorectal cancer (CRC) cells by promoting NHEJ repair efficiency. Mechanistically, GLTSCR1 interacts with BRD9 to engage in the assembly of the non-canonical BAF complex (GBAF). However, GLTSCR1 deficiency disrupts GBAF and triggers the ubiquitination degradation of BRD9. Furthermore, GLTSCR1 deficiency causes aberrant opening in the promoter region of NHEJ repair-associated genes, which promotes CRC development. While, GLTSCR1 and its binding partner BRD9 are not directly involved in assembling NHEJ repair machinery; instead, they regulate the DNA accessibility of NHEJ repair-associated genes. Collectively, our findings confirm GLTSCR1 deficiency as a critical regulatory event of the NHEJ pathway in CRC development, which might require different therapeutic strategy for GLTSCR1 wild-type and mutant CRC.

MiR-5195-3p predicts clinical prognosis and represses colorectal cancer progression by targeting TLR4/MyD88 signaling

BackgroundRecent studies have highlighted the role of miR-5195-3p in suppressing cell growth in various cancers. However, the specific functional impact of miR-5195-3p in colorectal cancer (CRC) remain to be fully clarified. The importance of miR-5195-3p in CRC was evaluated, aiming to uncover its underlying molecular mechanism and identify it as a potential therapeutic target for CRC.ResultsOur research has shown that miR-5195-3p is markedly under-expressed in CRC tissues and cell cultures, with its reduced presence associated with a higher TNM stage, lymphatic invasion, and unfavorable survival outcome. Ectopic miR-5195-3p expression curtailed proliferation, migration, and invasion of SW1116 and HT29 cells. Additionally, we discovered that miR-5195-3p directly targets and negatively influences Toll-like receptor 4 (TLR4) in CRC cells. Moreover, an inverse relationship was noted between miR-5195-3p and TLR4 expression in CRC tissue samples. Notably, restoring TLR4 expression counteracted miR-5195-3p’s suppressive impact on cell growth, motility, invasiveness, epithelial-mesenchymal transition (EMT), and the TLR4/MyD88 signaling pathway in SW1116 and HT29 cells.ConclusionsMiR-5195-3p suppresses the CRC cellular functions through the downregulation of TLR4/MyD88 signaling, indicating that targeting miR-5195-3p might offer a viable therapeutic strategy for CRC.

Targeting PARP-1 and DNA Damage Response Defects in Colorectal Cancer Chemotherapy with Established and Novel PARP Inhibitors.

The DNA repair protein PARP-1 emerged as a valuable target in the treatment of tumor entities with deficiencies of BRCA1/2, such as breast cancer. More recently, the application of PARP inhibitors (PARPi) such as olaparib has been expanded to other cancer entities including colorectal cancer (CRC). We previously demonstrated that PARP-1 is overexpressed in human CRC and promotes CRC progression in a mouse model. However, acquired resistance to PARPi and cytotoxicity-mediated adverse effects limit their clinical applicability. Here, we detailed the role of PARP-1 as a therapeutic target in CRC and studied the efficacy of novel PARPi compounds in wildtype (WT) and DNA repair-deficient CRC cell lines together with the chemotherapeutics irinotecan (IT), 5-fluorouracil (5-FU), and oxaliplatin (OXA). Based on the ComPlat molecule archive, we identified novel PARPi candidates by molecular docking experiments in silico, which were then confirmed by in vitro PARP activity measurements. Two promising candidates (X17613 and X17618) also showed potent PARP-1 inhibition in a CRC cell-based assay. In contrast to olaparib, the PARPi candidates caused no PARP-1 trapping and, consistently, were not or only weakly cytotoxic in WT CRC cells and their BRCA2- or ATR-deficient counterparts. Importantly, both PARPi candidates did not affect the viability of nonmalignant human colonic epithelial cells. While both olaparib and veliparib increased the sensitivity of WT CRC cells towards IT, no synergism was observed for X17613 and X17618. Finally, we provided evidence that all PARPi (olaparib > veliparib > X17613 > X17618) synergize with chemotherapeutic drugs (IT > OXA) in a BRCA2-dependent manner in CRC cells, whereas ATR deficiency had only a minor impact. Collectively, our study identified novel lead structures with potent PARP-1 inhibitory activity in CRC cells but low cytotoxicity due to the lack of PARP-1 trapping, which synergized with IT in homologous recombination deficiency.

FUT2 promotes colorectal cancer metastasis by reprogramming fatty acid metabolism via YAP/TAZ signaling and SREBP-1

Colorectal cancer (CRC) ranks as the second most lethal cancer worldwide because of its high rate of metastasis, and approximately 20% of CRC patients have metastases at initial diagnosis. Metabolic reprogramming, a hallmark of cancer cells, has been implicated in the process of metastasis. We previously demonstrated that fucosyltransferase 2 (FUT2) promotes the malignancy of CRC cells, however, the underlying mechanisms remain unclear. Here, bioinformatic analysis revealed that FUT2 is associated with the malignant phenotype and fatty acid metabolism in CRC. FUT2 knockdown decreased glucose uptake and de novo fatty acid synthesis, which in turn inhibited the proliferation and metastasis of CRC cells. Mechanistically, FUT2 promotes YAP1 nuclear translocation and stabilizes mSREBP-1 by fucosylation, thus promoting de novo fatty acid synthesis in CRC cells. In summary, this study demonstrates that FUT2 promotes the proliferation and metastasis of CRC cells by reprogramming fatty acid metabolism via YAP/TAZ signaling and SREBP-1, indicating that FUT2 might be a potential target for developing therapeutic strategies against CRC.

DNA methylation-driven gene FAM3D promotes colorectal cancer growth via the ATF4-SESN2-mTORC1 pathway.

Globally, colorectal cancer (CRC) is the malignant tumor with the highest mortality rate after lung cancer. Abnormal DNA methylation drives dysregulated gene expression, thereby promoting CRC progression and leading to poor prognosis. We identified a 3-CpG methylation signature that is independently associated with CRC prognosis. The model consists of three methylation-driven genes: FAM3 Metabolism Regulating Signaling Molecule D (FAM3D), DAPP1, and PIGR. However, the prognostic significance, biological function, and related mechanisms of the individual methylation-driven gene FAM3D in CRC have not been studied. Here, we discovered that FAM3D expression was reduced in CRC tissues and cells, and that high methylation and low expression of FAM3D were independent prognostic risk factors for CRC. In addition, FAM3D promoted the growth and movement of CRC cells in vitro and the proliferation in nude mice, mainly by inhibiting ATF4 transcription and downregulating SESN2 expression, and ultimately activating mTORC1. Furthermore, FAM3D resulted in reduced sensitivity of CRC cells to oxaliplatin, cisplatin, and 5-fluorouracil. Our study showed that FAM3D activates the mTORC1 pathway through the ATF4-SESN2 axis and promotes the malignant progression of CRC, which contributes to predict CRC prognosis and guide individualized treatment.

Microarray analysis points to LMNB1 and JUN as potential target genes for predicting metastasis promotion by etoposide in colorectal cancer

Etoposide is a second-line chemotherapy agent widely used for metastatic colorectal cancer. However, we discovered that etoposide treatment induced greater motility potential in four colorectal cancer cell lines. Therefore, we used microarrays to test the mRNA of these cancer cell lines to investigate the mechanisms of etoposide promoting colorectal cancer metastasis. Differentially expressed genes (DEGs) were identified by comparing the gene expression profiles in samples from etoposide-treated cells and untreated cells in all four colorectal cancer cell lines. Next, these genes went through the Gene Set Enrichment Analysis (GSEA), Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway analysis. Among the top 10 genes including the upregulated and downregulated, eight genes had close interaction according to the STRING database: FAS, HMMR, JUN, LMNB1, MLL3, PLK2, STAG1 and TBL1X. After etoposide treatment, the cell cycle, metabolism-related and senescence signaling pathways in the colorectal cancer cell lines were significantly downregulated, whereas necroptosis and oncogene pathways were significantly upregulated. We suggest that the differentially expressed genes LMNB1 and JUN are potential targets for predicting colorectal cancer metastasis. These results provide clinical guidance in chemotherapy, and offer direction for further research in the mechanism of colorectal cancer metastasis.

DNA demethylation triggers cell free DNA release in colorectal cancer cells

BackgroundLiquid biopsy based on cell-free DNA (cfDNA) analysis holds significant promise as a minimally invasive approach for the diagnosis, genotyping, and monitoring of solid malignancies. Human tumors release cfDNA in the bloodstream through a combination of events, including cell death, active and passive release. However, the precise mechanisms leading to cfDNA shedding remain to be characterized. Addressing this question in patients is confounded by several factors, such as tumor burden extent, anatomical and vasculature barriers, and release of nucleic acids from normal cells. In this work, we exploited cancer models to dissect basic mechanisms of DNA release.MethodsWe measured cell loss ratio, doubling time, and cfDNA release in the supernatant of a colorectal cancer (CRC) cell line collection (N = 76) representative of the molecular subtypes previously identified in cancer patients. Association analyses between quantitative parameters of cfDNA release, cell proliferation, and molecular features were evaluated. Functional experiments were performed to test the impact of modulating DNA methylation on cfDNA release.ResultsHigher levels of supernatant cfDNA were significantly associated with slower cell cycling and increased cell death. In addition, a higher cfDNA shedding was found in non-CpG Island Methylator Phenotype (CIMP) models. These results indicate a positive correlation between lower methylation and increased cfDNA levels. To explore this further, we exploited methylation microarrays to identify a subset of probes significantly associated with cfDNA shedding and derive a methylation signature capable of discriminating high from low cfDNA releasers. We applied this signature to an independent set of 176 CRC cell lines and patient derived organoids to select 14 models predicted to be low or high releasers. The methylation profile successfully predicted the amount of cfDNA released in the supernatant. At the functional level, genetic ablation of DNA methyl-transferases increased chromatin accessibility and DNA fragmentation, leading to increased cfDNA release in isogenic CRC cell lines. Furthermore, in vitro treatment of five low releaser CRC cells with a demethylating agent was able to induce a significant increase in cfDNA shedding.ConclusionsMethylation status of cancer cell lines contributes to the variability of cfDNA shedding in vitro. Changes in methylation pattern are associated with cfDNA release levels and might be exploited to increase sensitivity of liquid biopsy assays.