Human Colorectal Cancer Tissues Research Articles

GOLPH3 inhibits erastin-induced ferroptosis in colorectal cancer cells.

Ferroptosis is a novel form of programmed cell death and is considered to be a druggable target for colorectal cancer (CRC) therapy. However, the role of ferroptosis in CRC and its underlying mechanism are not fully understood. In the present study we found that a protein enriched in the Golgi apparatus, Golgi phosphoprotein 3 (GOLPH3), was overexpressed in human CRC tissue and in several CRC cell lines. The expression of GOLPH3 was significantly correlated with the expression of ferroptosis-related genes in CRC. The overexpression of GOLPH3 in Erastin-induced Caco-2 CRC cells reduced ferroptotic phenotypes, whereas the knockdown of GOLPH3 potentiated ferroptosis in HT-29 CRC cells. GOLPH3 induced the expression of prohibitin-1 (PHB1) and prohibitin-2 (PHB2), which also inhibited ferroptosis in Erastin-treated CRC cells. Moreover, GOLPH3 interacted with PHB2 and nuclear factor erythroid 2-related factor 2 (NRF2) in Caco-2 cells. These observations indicate that GOLPH3 is a negative regulator of ferroptosis in CRC cells. GOLPH3 protects these cells from ferroptosis by inducing the expression of PHB1 and PHB2, and by interacting with PHB2 and NRF2.

EEF1D stabilized by SRSF9 promotes colorectal cancer via enhancing the proliferation and metastasis.

Colorectal cancer (CRC) is the third most common cancer and causes high mortality worldwide. Although CRC has been studied widely, the molecular mechanism is not completely known. Eukaryotic translation elongation factor 1 delta (EEF1D) participates in the progression of various tumors, however, the effect of EEF1D on CRC remains unclear. Here, we aimed to identify the potential mechanism of EEF1D in CRC. The expression levels of EEF1D were assessed in CRC samples. Functional analysis of EEF1D in CRC was detected in vitro and in vivo. The regulatory mechanism of EEF1D was identified with RNA immunoprecipitation, RNA pull-down assay, and proteomics analysis. Our findings confirmed that EEF1D was upregulated in human CRC tissues. Functionally, EEF1D overexpression accelerated cell proliferation and metastasis, whereas EEF1D knockdown inhibited cell proliferation and metastasis both in vitro and in vivo CRC models. Furthermore, we showed that EEF1D was upregulated by SRSF9 via binding to 3'UTR of EEF1D mRNA. EEF1D knockdown reversed the malignant phenotype induced by SRSF9 overexpression. These findings demonstrated that EEF1D promotes CRC progression, and EEF1D may be a molecular target against CRC.

Hydrogen bond-modulated copper nanocluster-aggregation-induced enhanced ECL with layered double hydroxides-sensing interface for miRNA-135b detection in colorectal cancer

Herein, we developed a novel electrochemiluminescence (ECL) sensing interface based on Mg/Fe layered double hydroxides nanosheets (LDHs) for miRNA-135b detection in human colorectal cancer tissues. The LDHs nanosheet with large specific surface area and abundant active sites can work as the electrode sensing interface to effectively catalyze the electrochemical reactions. Furthermore, the formation of hydrogen bonds between 4-carboxyphenylboronic acid (CBPA) on the copper nanoclusters (Cu NCs) and fluorine ions limited the intramolecular vibration and accelerated electron transfer, greatly improving the luminescence signal. Due to the catalysis of LDH and the aggregation-induced enhanced electrochemiluminescence (AIECL) effect, the ECL quantum yield of Cu NCs has been significantly amplified. The Mg/Fe LDH-based sensing system for miRNA-135b detection had a linear detection range of 10 fM–10 μM with a detection limit of 3.5 fM. Finally, the cancer tissue extracted from colorectal cancer patients have been successfully detected. The result indicated that the Mg/Fe LDHs sensing interface provided a new and reliable pathway for ECL analysis performance.

Confined bioprinting and culture in inflatable bioreactor for the sterile bioproduction of tissues and organs

The future of organ and tissue biofabrication strongly relies on 3D bioprinting technologies. However, maintaining sterility remains a critical issue regardless of the technology used. This challenge becomes even more pronounced when the volume of bioprinted objects approaches organ dimensions. Here, we introduce a novel device called the Flexible Unique Generator Unit (FUGU), which is a unique combination of flexible silicone membranes and solid components made of stainless steel. Alternatively, the solid components can also be made of 3D printed medical-grade polycarbonate. The FUGU is designed to support micro-extrusion needle insertion and removal, internal volume adjustment, and fluid management. The FUGU was assessed in various environments, ranging from custom-built basic cartesian to sophisticated 6-axis robotic arm bioprinters, demonstrating its compatibility, flexibility, and universality across different bioprinting platforms. Sterility assays conducted under various infection scenarios highlight the FUGU’s ability to physically protect the internal volume against contaminations, thereby ensuring the integrity of the bioprinted constructs. The FUGU also enabled bioprinting and cultivation of a 14.5 cm3 human colorectal cancer tissue model within a completely confined and sterile environment, while allowing for the exchange of gases with the external environment. This FUGU system represents a significant advancement in 3D bioprinting and biofabrication, paving the path toward the sterile production of implantable tissues and organs.

MicroRNA 429 regulates MMPs expression by modulating TIMP2 expression in colon cancer cells and inflammatory colitis.

In a previous study, we found that the expression of microRNA 429 (MIR429) was decreased in dextran sodium sulfate (DSS)-induced mouse colitis tissues. In this study, we aimed to investigate the interaction of MIR429 with TIMP metallopeptidase inhibitor 2 (TIMP2), one of its candidate target genes, in human colorectal cancer (CRC) cells and DSS-induced mouse colitis tissues. A luciferase reporter system was used to confirm the effect of MIR429 on TIMP2 expression. The expression levels of MIR429 and target genes in cells or tissues were evaluated through quantitative RT-PCR, western blotting, or immunohistochemistry. We found that the expression level of MIR429 was downregulated in human CRC tissues, and also showed that TIMP2 is a direct target gene of MIR429 in CRC cell lines. Furthermore, MIR429 regulate TIMP2-mediated matrix metallopeptidases (MMPs) expression in CRC cells. We also generated cell lines stably expressing MIR429 in CRC cell lines and showed that MIR429 regulates the expression of MMPs by mediating TIMP2 expression. In addition to human CRC tissues, we found that TIMP2 was highly expressed in mouse colitis tissues and human ulcerative colitis (UC) tissues. Our findings suggest that the expression of endogenous MIR429 was reduced in human CRC tissues and colitis, leading to upregulation of its target gene TIMP2. The upregulation of TIMP2 by decreased MIR429 expression in CRC tissues and inflamed tissues suggests that it may affect extracellular matrix (ECM) remodeling through downregulation of MMPs. Therefore, MIR429 may have therapeutic value for human CRC and colitis.

Colon and lung cancer classification from multi-modal images using resilient and efficient neural network architectures

Automatic classification of colon and lung cancer images is crucial for early detection and accurate diagnostics. However, there is room for improvement to enhance accuracy, ensuring better diagnostic precision. This study introduces two novel dense architectures (D1 and D2) and emphasizes their effectiveness in classifying colon and lung cancer from diverse images. It also highlights their resilience, efficiency, and superior performance across multiple datasets. These architectures were tested on various types of datasets, including NCT-CRC-HE-100K (set of 100,000 non-overlapping image patches from hematoxylin and eosin (H&E) stained histological images of human colorectal cancer (CRC) and normal tissue), CRC-VAL-HE-7K (set of 7180 image patches from N = 50 patients with colorectal adenocarcinoma, no overlap with patients in NCT-CRC-HE-100K), LC25000 (Lung and Colon Cancer Histopathological Image), and IQ-OTHNCCD (Iraq-Oncology Teaching Hospital/National Center for Cancer Diseases), showcasing their effectiveness in classifying colon and lung cancers from histopathological and Computed Tomography (CT) scan images. This underscores the multi-modal image classification capability of the proposed models. Moreover, the study addresses imbalanced datasets, particularly in CRC-VAL-HE-7K and IQ-OTHNCCD, with a specific focus on model resilience and robustness. To assess overall performance, the study conducted experiments in different scenarios. The D1 model achieved an impressive 99.80 % accuracy on the NCT-CRC-HE-100K dataset, with a Jaccard Index (J) of 0.8371, a Matthew's Correlation Coefficient (MCC) of 0.9073, a Cohen's Kappa (Kp) of 0.9057, and a Critical Success Index (CSI) of 0.8213. When subjected to 10-fold cross-validation on LC25000, the D1 model averaged (avg) 99.96 % accuracy (avg J, MCC, Kp, and CSI of 0.9993, 0.9987, 0.9853, and 0.9990), surpassing recent reported performances. Furthermore, the ensemble of D1 and D2 reached 93 % accuracy (J, MCC, Kp, and CSI of 0.7556, 0.8839, 0.8796, and 0.7140) on the IQ-OTHNCCD dataset, exceeding recent benchmarks and aligning with other reported results. Efficiency evaluations were conducted in various scenarios. For instance, training on only 10 % of LC25000 resulted in high accuracy rates of 99.19 % (J, MCC, Kp, and CSI of 0.9840, 0.9898, 0.9898, and 0.9837) (D1) and 99.30 % (J, MCC, Kp, and CSI of 0.9863, 0.9913, 0.9913, and 0.9861) (D2). In NCT-CRC-HE-100K, D2 achieved an impressive 99.53 % accuracy (J, MCC, Kp, and CSI of 0.9906, 0.9946, 0.9946, and 0.9906) with training on only 30 % of the dataset and testing on the remaining 70 %. When tested on CRC-VAL-HE-7K, D1 and D2 achieved 95 % accuracy (J, MCC, Kp, and CSI of 0.8845, 0.9455, 0.9452, and 0.8745) and 96 % accuracy (J, MCC, Kp, and CSI of 0.8926, 0.9504, 0.9503, and 0.8798), respectively, outperforming previously reported results and aligning closely with others. Lastly, training D2 on just 10 % of NCT-CRC-HE-100K and testing on CRC-VAL-HE-7K resulted in significant outperformance of InceptionV3, Xception, and DenseNet201 benchmarks, achieving an accuracy rate of 82.98 % (J, MCC, Kp, and CSI of 0.7227, 0.8095, 0.8081, and 0.6671). Finally, using explainable AI algorithms such as Grad-CAM, Grad-CAM++, Score-CAM, and Faster Score-CAM, along with their emphasized versions, we visualized the features from the last layer of DenseNet201 for histopathological as well as CT-scan image samples. The proposed dense models, with their multi-modality, robustness, and efficiency in cancer image classification, hold the promise of significant advancements in medical diagnostics. They have the potential to revolutionize early cancer detection and improve healthcare accessibility worldwide.

Overexpression of Fatty Acid Synthase Upregulates Glutamine-Fructose-6-Phosphate Transaminase 1 and O-Linked N-Acetylglucosamine Transferase to Increase O-GlcNAc Protein Glycosylation and Promote Colorectal Cancer Growth.

Fatty acid synthesis has been extensively investigated as a therapeutic target in cancers, including colorectal cancer (CRC). Fatty acid synthase (FASN), a key enzyme of de novo lipid synthesis, is significantly upregulated in CRC, and therapeutic approaches of targeting this enzyme are currently being tested in multiple clinical trials. However, the mechanisms behind the pro-oncogenic action of FASN are still not completely understood. Here, for the first time, we show that overexpression of FASN increases the expression of glutamine-fructose-6-phosphate transaminase 1 (GFPT1) and O-linked N-acetylglucosamine transferase (OGT), enzymes involved in hexosamine metabolism, and the level of O-GlcNAcylation in vitro and in vivo. Consistently, expression of FASN significantly correlates with expression of GFPT1 and OGT in human CRC tissues. shRNA-mediated downregulation of GFPT1 and OGT inhibits cellular proliferation and the level of protein O-GlcNAcylation in vitro, and knockdown of GFPT1 leads to a significant decrease in tumor growth and metastasis in vivo. Pharmacological inhibition of GFPT1 and OGT leads to significant inhibition of cellular proliferation and colony formation in CRC cells. In summary, our results show that overexpression of FASN increases the expression of GFPT1 and OGT as well as the level of protein O-GlcNAcylation to promote progression of CRC; targeting the hexosamine biosynthesis pathway could be a therapeutic approach for this disease.

C16, a PKR inhibitor, suppresses cell proliferation by regulating the cell cycle via p21 in colorectal cancer

Double-stranded RNA-activated protein kinase R (PKR) is highly expressed in colorectal cancer (CRC). However, the role of PKR in CRC remains unclear. The aim of this study was to clarify whether C16 (a PKR inhibitor) exhibits antitumor effects and to identify its target pathway in CRC. We evaluated the effects of C16 on CRC cell lines using the MTS assay. Enrichment analysis was performed to identify the target pathway of C16. The cell cycle was analyzed using flow cytometry. Finally, we used immunohistochemistry to examine human CRC specimens. C16 suppressed the proliferation of CRC cells. Gene Ontology (GO) analysis revealed that the cell cycle-related GO category was substantially enriched in CRC cells treated with C16. C16 treatment resulted in G1 arrest and increased p21 protein and mRNA expression. Moreover, p21 expression was associated with CRC development as observed using immunohistochemical analysis of human CRC tissues. C16 upregulates p21 expression in CRC cells to regulate cell cycle and suppress tumor growth. Thus, PKR inhibitors may serve as a new treatment option for patients with CRC.

LPCAT2 inhibits colorectal cancer progression via the PRMT1/SLC7A11 axis

Colorectal cancer (CRC) has a high degree of heterogeneity and identifying the genetic information of individual tumor cells could help enhance our understanding of tumor biology and uncover potential therapeutic targets for CRC. In this study, we identified LPCAT2+ tumor cell populations with less malignancy than LPCAT2- tumor cells in human and mouse CRC tissues using scRNA-seq. Combining in vitro and in vivo experiments, we found that LPCAT2 could inhibit the proliferation of CRC cells by inducing ferroptosis. Mechanistically, LPCAT2 arrested PRMT1 in cytoplasm of CRC cells via regulating acetylation of PRMT1 at the K145 site. In turn, PRMT1 enhanced SLC7A11 promoter activity. Thus, LPCAT2 attenuated the positive regulatory effect of PRMT1 on SLC7A11 promoter. Notably, SLC7A11 acts as a ferroptosis regulator. Furthermore, in LPCAT2 knockout mice (LPCAT2−/−) colon cancer model, we found that LPCAT2−/− mice exhibited more severe lesions, while PRMT1 or SLC7A11 inhibitors delayed the progression. Altogether, we elucidated that LPCAT2 suppresses SLC7A11 expression by inhibiting PRMT1 nuclear translocation, thereby inducing ferroptosis in CRC cells. Moreover, inhibitors of the PRMT1/SLC7A11 axis could delay tumor progression in CRC with low LPCAT2 expression, making it a potentially effective treatment for CRC.

Therapy-induced senescent tumor cell-derived extracellular vesicles promote colorectal cancer progression through SERPINE1-mediated NF-κB p65 nuclear translocation

BackgroundCellular senescence frequently occurs during anti-cancer treatment, and persistent senescent tumor cells (STCs) unfavorably promote tumor progression through paracrine secretion of the senescence-associated secretory phenotype (SASP). Extracellular vesicles (EVs) have recently emerged as a novel component of the SASP and primarily mediate the tumor-promoting effect of the SASP. Of note, the potential effect of EVs released from STCs on tumor progression remains largely unknown.MethodsWe collected tumor tissues from two cohorts of colorectal cancer (CRC) patients to examine the expression of p16, p21, and SERPINE1 before and after anti-cancer treatment. Cohort 1 included 22 patients with locally advanced rectal cancer (LARC) who received neoadjuvant therapy before surgical resection. Cohort 2 included 30 patients with metastatic CRC (mCRC) who received first-line irinotecan-contained treatment. CCK-8, transwell, wound-healing assay, and tumor xenograft experiments were carried out to determine the impacts of EVs released from STCs on CRC progression in vitro and in vivo. Quantitative proteomic analysis was applied to identify protein cargo inside EVs secreted from STCs. Immunoprecipitation and mass spectrometer identification were utilized to explore the binding partners of SERPINE1. The interaction of SERPINE1 with p65 was verified by co-immunoprecipitation, and their co-localization was confirmed by immunofluorescence.ResultsChemotherapeutic agents and irradiation could potently induce senescence in CRC cells in vitro and in human CRC tissues. The more significant elevation of p16 and p21 expression in patients after anti-cancer treatment displayed shorter disease-free survival (DFS) for LARC or progression-free survival (PFS) for mCRC. We observed that compared to non-STCs, STCs released an increased number of EVs enriched in SERPINE1, which further promoted the progression of recipient cancer cells. Targeting SERPINE1 with a specific inhibitor, tiplaxtinin, markedly attenuated the tumor-promoting effect of STCs-derived EVs. Additionally, the patients with greater increment of SERPINE1 expression after anti-cancer treatment had shorter DFS for LARC or PFS for mCRC. Mechanistically, SERPINE1 bound to p65, promoting its nuclear translocation and subsequently activating the NF-κB signaling pathway.ConclusionsWe provide the in vivo evidence of the clinical prognostic implications of therapy-induced senescence. Our results revealed that STCs were responsible for CRC progression by producing large amounts of EVs enriched in SERPINE1. These findings further confirm the crucial role of therapy-induced senescence in tumor progression and offer a potential therapeutic strategy for CRC treatment.

Colorectal cancer cells secreting DKK4 transform fibroblasts to promote tumour metastasis

Wnt/β-catenin signalling is aberrantly activated in most colorectal cancer (CRC) and is one key driver involved in the initiation and progression of CRC. However, mutations of APC gene in CRC patients retain certain activity of APC protein with decreased β-catenin signalling and DKK4 expression significantly upregulates and represses Wnt/β-catenin signalling in human CRC tissues, suggesting that a precisely modulated activation of the Wnt/β-catenin pathway is essential for CRC formation and progression. The underlying reasons why a specifically reduced degree, not a fully activating degree, of β-catenin signalling in CRC are unclear. Here, we showed that a soluble extracellular inhibitor of Wnt/β-catenin signalling, DKK4, is an independent factor for poor outcomes in CRC patients. DKK4 secreted from CRC cells inactivates β-catenin in fibroblasts to induce the formation of stress fibre-containing fibroblasts and myofibroblasts in culture conditions and in mouse CRC xenograft tissues, resulting in restricted expansion in tumour masses at primary sites and enhanced CRC metastasis in mouse models. Reduced β-catenin activity by a chemical inhibitor MSAB promoted the CRC metastasis. Our findings demonstrate why reduced β-catenin activity is needed for CRC progression and provide a mechanism by which interactions between CRC cells and stromal cells affect disease promotion.

Abstract 2765: Novel WNT-RIP1-GDF15 pathway promotes migration and invasion of colorectal cancer cells

Abstract Growth-differentiation factor 15 (GDF15) is a member of the transforming growth factor β (TGF-β) family protein, also known as NSAID-activated gene 1 (NAG-1) or macrophage inhibitory cytokine 1 (MIC-1), and is a major cause of cancer cachexia, cardiovascular disease, and various inflammatory diseases. Roles of GDF15 as major inflammatory response factor also have been demonstrated in animal models, and it has also showed various malignant functions such as regulating metabolism, promoting metastasis by inducing EMT in cancer. Here, we revealed a novel potential role for RIP1 in colorectal cancer (CRC) in enhancing metastasis by controlling WNT-RIP1-GDF15 signaling. We showed that WNT3A treatment increased the expression of GDF15 and GFRAL. Immunohistochemical analysis of human CRC tissue arrays consisting of primary cancer and metastatic cancer also confirmed that the expression of GDF15 and GFRAL was increased in metastatic cancer. Human XL cytokine assay, western blot, and ELISA results confirmed that GDF15 expression was reduced in cell lines in which RIP1 was knocked down. Reduction of GDF15 expression and secretion by RIP1 knockdown showed suppression of EMT induction resulting to decrease of migration and invasion of CRC cells. Taken together, these results suggest a novel EMT-enhancing role for RIP1 in the WNT pathway and suggest a novel WNT-RIP1-GDF15 pathway contributing to CRC malignancy by promoting EMT. Citation Format: A-Ram Kang, Do Hoon Kim, Jong Kuk Park. Novel WNT-RIP1-GDF15 pathway promotes migration and invasion of colorectal cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2765.

ART1 knockdown decreases the IL-6-induced proliferation of colorectal cancer cells

Colorectal cancer (CRC) is a worldwide health concern. Chronic inflammation is a risk factor for CRC, and interleukin-6 (IL-6) plays a pivotal role in this process. Arginine-specific mono-ADP-ribosyltransferase-1 (ART1) positively regulates inflammatory cytokines. ART1 knockdown reduces the level of glycoprotein 130 (gp130), a key transducer in the IL-6 signalling pathway. However, the relationship between ART1 and IL-6 and the resulting effects on IL-6-induced proliferation in CRC cells remain unclear. The aims of this study were to investigate the effects of ART1 knockdown on IL-6-induced cell proliferation in vitro and use an in vivo murine model to observe the growth of transplanted tumours. The results showed that compared with the control, ART1-sh cancer cells induced by IL-6 exhibited reduced viability, a lower rate of colony formation, less DNA synthesis, decreased protein levels of gp130, c-Myc, cyclin D1, Bcl-xL, and a reduced p-STAT3/STAT3 ratio (P < 0.05). Moreover, mice transplanted with ART1-sh CT26 cells that had high levels of IL-6 displayed tumours with smaller volumes (P < 0.05). ART1 and gp130 were colocalized in CT26, LoVo and HCT116 cells, and their expression was positively correlated in human CRC tissues. Overall, ART1 may serve as a promising regulatory factor for IL-6 signalling and a potential therapeutic target for human CRC.

MTORC2-AKT signaling to PFKFB2 activates glycolysis that enhances stemness and tumorigenicity of intestinal epithelial cells.

Although elevated glycolysis has been widely recognized as a hallmark for highly proliferating cells like stem cells and cancer, its regulatory mechanisms are still being updated. Here, we found a previously unappreciated mechanism of mammalian target of rapamycin complex 2 (mTORC2) in regulating glycolysis in intestinal stem cell maintenance and cancer progression. mTORC2 key subunits expression levels and its kinase activity were specifically upregulated in intestinal stem cells, mouse intestinal tumors, and human colorectal cancer (CRC) tissues. Genetic ablation of its key scaffolding protein Rictor in both mouse models and cell lines revealed that mTORC2 played an important role in promoting intestinal stem cell proliferation and self-renewal. Moreover, utilizing mouse models and organoid culture, mTORC2 loss of function was shown to impair growth of gut adenoma and tumor organoids. Based on these findings, we performed RNA-seq and noticed significant metabolic reprogramming in Rictor conditional knockout mice. Among all the pathways, carbohydrate metabolism was most profoundly altered, and further studies demonstrated that mTORC2 promoted glycolysis in intestinal epithelial cells. Most importantly, we showed that a rate-limiting enzyme in regulating glycolysis, 6-phosphofructo-2-kinase (PFKFB2), was a direct target for the mTORC2-AKT signaling. PFKFB2 was phosphorylated upon mTORC2 activation, but not mTORC1, and this process was AKT-dependent. Together, this study has identified a novel mechanism underlying mTORC2 activated glycolysis, offering potential therapeutic targets for treating CRC.

Precursor exhausted CD8+T cells in colorectal cancer tissues associated with patient's survival and immunotherapy responsiveness.

Exhausted CD8+T cells represent a distinct cellular lineage that emerges during both chronic infections and cancers. Recent studies have shown that persistent antigen exposure can drive the differentiation of precursor exhausted CD8+T cells, termed Tpex cells, which are characterized as TCF-1+PD-1+CD8+T cells. Elevated Tpex cell frequencies in the tumor microenvironment (TME) are associated with improved overall survival (OS) in cancer patients and heightened responsiveness to anti-PD-1 therapy. In our present study, we utilized multi-color immunohistochemistry (mIHC) to determine the localization and clinical implications of tumor-infiltrating Tpex cells within the TME of human colorectal cancer (CRC) tissues. We also conducted a multi-omics integrative analysis using single-cell RNA sequencing (scRNA-seq) data derived from both the murine MC38 tumor model and human CRC tissues. This analysis helped delineate the transcriptional and functional attributes of Tpex cells within the CRC TME. Furthermore, we employed spatial transcriptome sequencing data from CRC patients to investigate the interactions between Tpex cells and other immune cell subsets within the TME. In conclusion, our study not only established a method for Tpex cell detection using mIHC technology but also confirmed that assessing Tpex cells within the CRC TME could be indicative of patients' survival. We further uncovered the transcriptional and functional characteristics of Tpex cells in the TME and ascertained their pivotal role in the efficacy of immunotherapy against CRC.

Decreased interleukin-17RA expression is associated with good prognosis in patients with colorectal cancer and inhibits tumor growth and vascularity in mice.

Interleukin-17 (IL-17) is a pro-inflammatory cytokine that plays a vital role in the promotion of tumorigenesis in various cancers, including colorectal cancer (CRC). Based on current evidence, IL-17 binds to interleukin-17 receptor A (IL-17RA); however, the role of IL-17RA has not been elucidated in previous studies on CRC. In this study, we explored the role of IL-17RA in human CRC tissues and the progression of CRC in humans and mice. The expressions of IL-17RA and epithelial-mesenchymal transition (EMT)-related genes were examined in CRC cells and tissue samples by quantitative real-time polymerase chain reaction. The role of IL-17RA in pathogenesis and prognosis was evaluated using a Chi-squared test, Kaplan-Meier analysis, univariate, and multivariate Cox regression analysis in 133 CRC patients. A tumor-bearing mice model was executed to evaluate the role of IL-17RA in tumor growth, vascularity and population of infiltrating immune cells. IL-17RA expression was found to be significantly higher in CRC tissues than in adjacent normal tissues. The expression of IL-17RA in Stage IV patients was significantly higher than that in Stages I and II patients. Patients with high IL-17RA expression exhibited significantly worse overall and CRC-specific survival than those with low IL-17RA expression. Functional assessment suggested that the knockdown of IL-17RA expression distinctly suppressed cellular proliferation, migration, invasion, and EMT-related gene expression. In a tumor-bearing mouse model, decreased IL-17RA expression significantly repressed tumor growth and vascularity and reduced the population of regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs). Reduced IL-17RA expression also suppressed cellular proliferation, migration, and invasion, and the expression of EMT genes. Knockdown of IL-17RA inhibited tumor growth and vascularity and decreased the population of Tregs and MDSCs in mouse tumors. Overall, IL-17RA expression was identified to be independently associated with the prognosis of patients with CRC.

Metformin Inhibits NLRP3 Inflammasome Expression and Regulates Inflammatory Microenvironment to Delay the Progression of Colorectal Cancer.

Colorectal cancer is a common malignant tumor, with about one million people diagnosed with it worldwide each year. Recent studies have found that metformin can inhibit the production of inflammatory factors and regulate the polarization of immune cells. However, whether metformin can regulate the inflammatory microenvironment and delay the progression of colorectal cancer by inhibiting the inflammatory response has not been deeply studied yet. This study aimed to explore the molecular mechanism by which metformin inhibits the expression of NLRP3 inflammasome, regulates the inflammatory microenvironment, and delays the progression of colorectal cancer through in vitro cell experiments. In this research, NLRP3 was knocked down in human colorectal cancer cells, and metformin was added to them. Cell proliferation ability was detected by CCK8, and cell migration and invasion abilities were assessed by Transwell assay. The apoptosis rate was determined by flow cytometry. In addition, the expression of NLRP3 inflammatory vesicles and inflammatory factors in each group of cells was studied by qRT-PCR and Western blotting. Finally, clinical colorectal cancer samples were analyzed by immunohistochemistry. The results of the study showed that NLRP3 expression was significantly increased in colorectal cancer cell lines and human colorectal cancer tissues. Knockdown of NLRP3 significantly inhibited tumor cell proliferation, migration, and invasion. In addition, the proliferation, migration and invasion of tumor cells were also significantly reduced by the addition of metformin intervention. Furthermore, qRT-PCR and WB results demonstrated that the expression of IL-1β, IL-6, TNF- α, TGF-β, and IL-10 was down-regulated in LS1034 tumor cells after NLRP3 knockdown. In addition, metformin intervention also resulted in different degrees of downregulation of NLRP3 and inflammatory factor expression (p <0.05). Notably, the reduction in inflammatory factors was more pronounced after the combination of NLRP3 knockdown and metformin intervention. Metformin can inhibit the expression of NLRP3 inflammasome, thereby suppressing the expression of inflammation-related factors, reducing the damage of the inflammatory microenvironment to normal cells, and delaying the progression of colorectal cancer.

Abstract IA023: Spatial reconstruction and temporal inference of DNA methylation alterations in primary human colorectal cancer

Abstract Phenotypic plasticity is thought to assist immune evasion, metastasis, and therapeutic resistance in tumor evolution. Epigenetic mechanisms such as DNA methylation provide for a more easily acquired and flexible, yet semi-stable adaptation by the tumor cell than hardwired genetic changes. Cancer-associated gain of DNA methylation at promoter CpG islands or distal regulatory elements is associated with transcriptional silencing, whereas loss of DNA methylation is observed at late-replicating, lamina-attached regions of the genome, tracking with cumulative cell divisions. One of the most well-documented genomic features predisposing to DNA hypermethylation is Polycomb Repressive Complex (PRC) occupancy in precursor cells, consistent with an epigenetic block to cellular differentiation as an early or predisposing event in carcinogenesis. A central question is whether this epigenetic switch from reversible PRC repression to more stable DNA hypermethylation occurs before onset of clonal expansion, or whether it represents an ongoing process during tumor evolution. Clonal expansion is a pivotal characteristic of cancer, and is thought to be initiated by a genetic alteration in a key gatekeeper driver gene. However, not all normal cells appear to be susceptible to malignant transformation following such an event. Multiple lines of evidence suggest that epigenetic heterogeneity among normal cells may affect their cancer-initiating potential. We have developed a tumor processing pipeline to deeply and comprehensively map DNA methylation patterns in primary human colorectal cancer (CRC) and adjacent tissues, while preserving spatial information, enabling inference of the temporal order of molecular alterations. We employ a suite of technologies to map the spatial heterogeneity of DNA methylation patterns in primary human CRC. These include a deep single-cell whole-genome bisulfite sequencing technique that improves genomic coverage several-fold over existing published protocols, providing DNA methylation measurements at the majority of CpGs in the genome in individual tumor cells. We have also calibrated and validated an epigenetic clock that allows us to accurately measure the relative replicative history of individual cells. We infer phylogenetic relationships among subclones, and relate these to their spatial distribution in the primary tumor. We find that some tumors have high proportions of PRC-associated clonal hypermethylation, indicating that these hypermethylation events were already present prior to clonal expansion, possibly contributing to susceptibility to malignant transformation in the cell-of-origin, whereas other tumors appear to have active PRC-associated CpG island hypermethylation ongoing during tumor expansion, generating subclonal heterogeneity, which may influence post-therapeutic recurrence potential. Citation Format: Peter W. Laird, Nathan J. Spix, Hsiao-yun Milliron, Manpreet Kalkat, Emily Eugster, David Sokol, Emily Jung, Paula Nolte, Kelly K. Krzyzanowski, Toshinori Hinoue, Hui Shen. Spatial reconstruction and temporal inference of DNA methylation alterations in primary human colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr IA023.

Clinical Significance of HHLA2 as a Novel Therapeutic Target for Colorectal Cancer.

Colorectal cancer (CRC) is a high-indence malignance of the digestive system with a high mortality rate in the world. The results are desired to provide an important theoretical basis for discovering new therapeutic targets for CRC. The expression of human endogenous retrovirus-H-long terminal repeat association protein 2 (HHLA2) in human CRC was detected to explore its correlationship with clinicopathological features and prognosis of patients and its potential in treating CRC. Western blot was employed to detect HHLA2 expression in fresh tissues obtained from 6 CRC patients' excisions, including cancer, paracancer, and normal issues. Immunohistochemical staining was employed to determine HHLA2 expression in paraffin-embedded specimens of 139 patients with colorectal cancer, and its relationship with the clinicopathological profiles and survival was analyzed. Small interfering RNA (siRNA) targeting HHLA2 was used to transfect CRC cells to silent HHLA2. MTT, plate colony formation, cell scratch, and Transwell assay were conducted to observe the proliferation, migration, and invasion of CRC cells. HHLA2 protein was expressed in human colorectal cancer tissues, paracancer tissues and normal tissues, which was significantly upregulated in cancer tissues (P<0.01). HHLA2 expression level in CRC tissues showed a close correlationship with the invasion depth of the tumor (P=0.000), metastasis of regional lymph nodes (P=0.018), clinical stage (P=0.010), and patient survival (P=0.011). Correlation with gender (P=0.873), age (P=0.864), location of the tumor (P=0.768), degree of tumor differentiation (P=0.569) and distant metastasis (P=0.494) exhibited no significance. The survival time of CRC patients with high and low HHLA2 expression groups was 43.231 months and 55.649 months, respectively, with a statistical difference between the two groups (P=0.001). Silencing HHLA2 inhibited proliferation, migration and invasion of CRC cells significantly. HHLA2 is overexpressed in CRC tissues which is associated with poor prognosis of patients. HHLA2 might be recognized as a new candidate for adjuvant diagnosis and prognosis of CRC, as well as a promised new target for immunotherapy of CRC.

Kaempferol inhibits colorectal cancer metastasis through circ_0000345 mediated JMJD2C/β-catenin signalling pathway

BackgroundRecurrence and metastasis are the main causes of disease deterioration in colorectal cancer (CRC) patients, yet efficient therapeutic strategies are lacking. Natural compounds for efficient antitumour therapeutics are becoming increasingly prominent. Kaempferol, one of the main components of flavonoids in plants, displays a variety of pharmacological activities. Our preliminary experiments suggested that kaempferol could inhibit CRC metastasis and is significantly associated with the β-catenin signalling pathway. Moreover, we also defined the regulatory roles of JMJD2C in β-catenin signalling in our previous work. PurposeThis study aims to reveal the mechanism by which kaempferol inhibits CRC progression and regulates the JMJD2C/β-catenin signalling pathway. MethodsThe migratory capabilities of CRC cells after kaempferol intervention were measured by scratch wound healing and transwell assays. Circ_0000345 knockdown CRC stable cell lines were generated by lentivirus infection. The possible mechanism of kaempferol on circ_0000345 was verified by molecular-protein docking and verification program cellular thermal shift assay (CETSA). A dual luciferase reporter gene assay was carried out for the targeting relationship among circ_0000345, miR-205-5p and JMJD2C. Fluorescence in situ hybridization (FISH) was performed to determine the expression of circ_0000345 in tumour tissues. A pulmonary metastatic model of CRC in vitro was built to assess the antimetastatic effect and mechanism of kaempferol in vivo. ResultsIn vitro, kaempferol inhibits the ability to migrate of CRC cells by reducing the activation of the JMJD2C/β-catenin signalling pathway. MiR-205-5p is a key bridge for kaempferol to inhibit the expression of JMJD2C. The function of miR-205-5p is impeded by circ_0000345, which shows higher expression levels in human metastatic CRC tissues than nonmetastatic CRC tissues, and its formation is regulated by the RNA-binding proteins HNRNPK and HNRNPL. Mechanistically, kaempferol physically interacts with HNRNPK and HNRNPL to suppress JMJD2C by downregulating the expression of circ_0000345. In vivo, kaempferol suppresses CRC lung metastasis. Kaempferol inhibits the activation of JMJD2C/β-catenin signalling through reducing the expression of circ_0000345 in the CRC lung metastasis model. ConclusionCirc_0000345 enhances activation of the JMJD2C/β-catenin signalling pathway through miR-205-5p to promote CRC metastasis. Kaempferol inhibits CRC metastasis through the circ_0000345-mediated JMJD2C/β-catenin signalling pathway, and this effect is influenced as a direct consequence of the binding of kaempferol with HNRNPK and HNRNPL. This provides promising therapeutic and/or adjuvant agents for advanced CRC and sheds light on the multifaceted role of phytomedicine in cancer.