HCT116 Human Colorectal Cancer Cells Research Articles

Activity of Hydrophilic, Biocompatible, Fluorescent, Organic Nanoparticles Functionalized with Purpurin-18 in Photodynamic Therapy for Colorectal Cancer.

Photodynamic therapy (PDT) is a clinically approved, non-invasive therapy currently used for several solid tumors, triggering cell death through the generation of reactive oxygen species (ROS). However, the hydrophobic nature of most of the photosensitizers used, such as chlorins, limits the overall effectiveness of PDT. To address this limitation, the use of nanocarriers seems to be a powerful approach. From this perspective, we have recently developed water-soluble and biocompatible, fluorescent, organic nanoparticles (FONPs) functionalized with purpurin-18 and its derivative, chlorin p6 (Cp6), as new PDT agents. In this study, we aimed to investigate the induced cell death mechanism mediated by these functionalized nanoparticles after PDT photoactivation. Our results show strong phototoxic effects of the FONPs[Cp6], mediated by intracellular ROS generation, and subcellular localization in HCT116 and HT-29 human colorectal cancer (CRC) cells. Additionally, we proved that, post-PDT, the FONPs[Cp6] induce apoptosis via the intrinsic mitochondrial pathway, as shown by the significant upregulation of the Bax/Bcl-2 ratio, the activation of caspases 9, 3, and 7, leading poly-ADP-ribose polymerase (PARP-1) cleavage, and DNA fragmentation. Our work demonstrates the photodynamic activity of these nanoparticles, making them promising candidates for the PDT treatment of CRC.

Acquired Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) Resistance of Human Colorectal Cancer Cells Is Linked to Histone Acetylation and Is Synergistically Ameliorated by Combination with HDAC Inhibitors.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an attractive target for the treatment of various malignancies; however, its therapeutic potential is limited because of the frequent occurrence of tumor cell resistance. In this study, we determined whether TRAIL resistance acquired by repeated administration could be overcome by HDAC inhibition in human colorectal cancer cells. TRAIL-resistant HCT116 human colorectal cancer cells (HCT116-TR) were generated by repeated treatment with 10 and 25 ng/mL TRAIL twice weekly for 28 days. The resulting TRAIL-resistant cells were noncross-resistant to other chemotherapeutic agents. The levels of histone acetylation-related proteins, such as ac-histone H4 and HDAC1, were altered in HCT116-TR cells compared with the parental HCT116 cell line. The combined treatment with TRAIL and HDAC inhibitors significantly increased apoptosis in HCT116-TR cells and indicated a synergistic effect. The mechanism by which HDAC inhibition sensitizes HCT116-TR cells to TRAIL is dependent on the intrinsic pathway. In addition, we found that HDAC inhibition enhanced the sensitivity of cells to TRAIL through mitogen-activated protein kinases/CCAAT/enhancer-binding protein homologs of protein-dependent upregulation of death receptor 5. These results suggest that histone acetylation is responsible for acquired TRAIL resistance after repeated exposure and acquired resistance to TRAIL may be overcome by combination therapies with HDAC inhibitors.

Novel ST1926 Nanoparticle Drug Formulation Enhances Drug Therapeutic Efficiency in Colorectal Cancer Xenografted Mice.

Cancer is a major public health problem that ranks as the second leading cause of death. Anti-cancer drug development presents with various hurdles faced throughout the process. Nanoparticle (NP) formulations have emerged as a promising strategy for enhancing drug delivery efficiency, improving stability, and reducing drug toxicity. Previous studies have shown that the adamantyl retinoid ST1926 displays potent anti-tumor activities in several types of tumors, particularly in colorectal cancer (CRC). However, phase I clinical trials in cancer patients using ST1926 are halted due to its low bioavailability. In this manuscript, we developed ST1926-NPs using flash nanoprecipitation with polystyrene-b-poly (ethyleneoxide) as an amphiphilic stabilizer and cholesterol as a co-stabilizer. Dynamic light scattering revealed that the resulting ST1926-NPs Contin diameter was 97 nm, with a polydispersity index of 0.206. Using cell viability, cell cycle analysis, and cell death assays, we showed that ST1926-NP exhibited potent anti-tumor activities in human CRC HCT116 cells. In a CRC xenograft model, mice treated with ST1926-NP exhibited significantly lowered tumor volumes compared to controls at low drug concentrations and enhanced the delivery of ST1926 to the tumors. These findings highlight the potential of ST1926-NPs in attenuating CRC tumor growth, facilitating its further development in clinical settings.

Studies on the ameliorative potential of Rheum webbianum rhizome extracts on 1,2-dimethylhydrazine (DMH) induced colorectal cancer and associated hepatic and haematological abnormalities in swiss albino rats

Ethnopharmacological relevanceRheum webbianum Royle (RW) holds significant ethnopharmacological importance owing to its 5000-year history of cultivation for medicinal and culinary purposes. Demonstrating therapeutic advantages in traditional and contemporary medical practices, RW exhibits key pharmacological effects including anticancer activity, gastrointestinal control, anti-inflammatory properties, and suppression of fibrosis. Despite its recognized vast bioactivities in ethnopharmacology, its efficacy against the colorectal cancer (CRC) remains incompletely understood. Aim of the studyThis study for the first time aims to investigate the chemo-preventive capabilities of various extracts derived from RW rhizomes against CRC development. Materials and methodsFour types of RW extracts were prepared by using different solvents viz: Hexane, Ethy-acetate, Ethanol and Methanol. All the four extracts were evaluated for cytotoxicity on HCT-116 human CRC cells. Promising extracts were further investigated in-vivo at varying doses using 1,2-dimethylhydrazine (DMH) induced rat CRC model to assess the anti-oxidant and anticancer properties as well as their effects on the associated hepatic deterioration and hematological alterations. ResultsCell viability: In-vitro assessments demonstrated a dose and time-dependent reduction in HCT-116 cell viability following treatment with methanolic and ethanolic extracts of RW, reducing viability by up to 85% and 90%, respectively, at 200 μg/ml. Histopathology: Histopathological analyses revealed significant improvements in colon tissue morphology in RW extract-treated groups compared to DMH-only treated animals. RW-treated groups showed reduced structural abnormalities, congestion, inflammatory cell infiltration, crypt abscess formation, and dysplasia. In contrast, the DMH-only group exhibited irregular glandular structure, mucosal destruction, extensive inflammatory cell infiltration, crypt abscess formation, and dysplasia. These results highlight the potential of RW methanolic and ethanolic extracts in mitigating colon cancer-related histopathological alterations. Haematological, and hepatic parameters: In the DMH-induced colorectal cancer rat model, significant hematological imbalances were evident, including a 49.13% decrease in erythrocytes, 32.18% in hemoglobin, and 26.79% in hematocrit, along with a 79.62% increase in white blood cells and 68.96% rise in platelets. Administration of RW rhizome extracts effectively restored these hematological parameters to levels comparable to those in the control group. Furthermore, RW treatment significantly reduced serum ALT and AST levels, which had increased by 36.78% and 33.12%, respectively, due to DMH exposure. RW intervention also mitigated the onset of atherosclerosis, evidenced by notable reductions in serum total cholesterol and triglyceride levels. Comparative analysis indicated that RW-treated DMH groups effectively restored lipid profiles, contrasting with the DMH-only group which exhibited markers indicative of colon cancer. Oxidative stress: The DMH-treated group showed a significant increase in MDA levels by 195.59%, indicative of heightened free radical production, coupled with decreased levels of SOD (33%), CAT (48%), GSH (58%), and GR activity (49%), signifying oxidative stress. Treatment with RW extracts in DMH-treated rats markedly reduced MDA levels and enhanced SOD, CAT, GSH, and GR activities. These results underscore the antioxidant efficacy of RW extracts. ConclusionThis study underscores the significant potential of RW rhizome extracts in inhibiting colorectal cancer development. Further investigations are warranted to identify the active constituents responsible for these promising outcomes, positioning RW as a natural and potential agent in combating colon cancer.

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.

Expression of PD-L1 Is Increased by Methionine Restriction Using Recombinant Methioninase in Human Colorectal Cancer Cells.

It has been recently demonstrated that a methionine-restricted diet increases the response to immune checkpoint inhibitors (ICIs) via an increase in PD-L1 in a syngeneic mouse colorectal-cancer model. Our laboratory has developed recombinant methioninase (rMETase) to restrict methionine. The aim of the present study was to determine if rMETase can increase PD-L1 expression in a human colorectal cancer cell line in vitro. We evaluated the half-maximal inhibitory concentration (IC50) value of rMETase on HCT-116 human colorectal cancer cells. HCT-116 cells were treated with rMETase at the IC50 Western immunoblotting was used to compare PD-L1 expression in HCT-116 cells treated with and without rMETase. The IC50 value of rMETase on HCT-116 was 0.79 U/ml. Methionine restriction using rMETase increased PD-L1 expression compared to the untreated control (p<0.05). Methionine restriction with rMETase up-regulates PD-L1 expression in human colorectal cancer cells and the combination of rMETase and ICIs may have the potential to improve immunotherapy in human colorectal cancer.

Domperidone, a Dopamine Receptor D2 Antagonist, Induces Apoptosis by Inhibiting the ERK/STAT3-Mediated Pathway in Human Colon Cancer HCT116 Cells.

Colorectal cancer (CRC) continues to demonstrate high incidence and mortality rates, emphasizing that implementing strategic measures for prevention and treatment is crucial. Recently, the dopamine receptor D2 (DRD2), a G protein-coupled receptor, has been reported to play multiple roles in growth of tumor cells. This study investigated the anticancer potential of domperidone, a dopamine receptor D2 antagonist, in HCT116 human CRC cells. Domperidone demonstrated concentration- and time-dependent reductions in cell viability, thereby inducing apoptosis. The molecular mechanism revealed that domperidone modulated the mitochondrial pathway, decreasing mitochondrial Bcl-2 levels, elevating cytosolic cytochrome C expression, and triggering caspase- 3, -7, and -9 cleavage. Domperidone decreased in formation of β-arrestin2/MEK complex, which contributing to inhibition of ERK activation. Additionally, treatment with domperidone diminished JAK2 and STAT3 activation. Treatment of U0126, the MEK inhibitor, resulted in reduced phosphorylation of MEK, ERK, and STAT3 without alteration of JAK2 activation, indicating that domperidone targeted both MEK-ERK-STAT3 and JAK2-STAT3 signaling pathways, respectively. Immunoblot analysis revealed that domperidone also downregulated DRD2 expression. Domperidone-induced reactive oxygen species (ROS) generation and N-acetylcysteine treatment mitigated ROS levels and restored cell viability. An in vivo xenograft study verified the significant antitumor effects of domperidone. These results emphasize the multifaceted anticancer effects of domperidone, highlighting its potential as a promising therapeutic agent for human CRC.

Terfenadine, a histamine H1 receptor antagonist, induces apoptosis by suppressing STAT3 signaling in human colorectal cancer HCT116 cells

Terfenadine, a histamine H1 receptor antagonist, induces apoptosis by suppressing STAT3 signaling in human colorectal cancer HCT116 cells

Short Chain Fatty Acid Sodium Butyrate Increases miR-21, miR-143 and miR-145 Expression in Human Colorectal Cancer HCT-116 Cell Line.

Sodium butyrate (NaBu) is a short-chain fatty acid; it is one of the histone deacetylase inhibitors, which can alter both genetic and epigenetic expressions. The present study aimed to elucidate the effect of Na-Bu on the expression of miR-21, miR-143, and miR-145 in human colorectal cancer HCT-116 cell lines. This study was done in Tehran Medical Sciences, Islamic Azad University, Tehran, Iran. HCT-116 cell line was treated with diverse concentrations of NaBu (6.25 mM to 200 mM) at 24, 48, and 72 h. MTT assay was used for assessing the cytotoxicity. Quantitative Real-Time-PCR was performed to investigate the gene expression of miR-21, miR-143, and miR-145. IC50 values were evaluated by MTT assay. IC50 for HCT-116 was 50 mM, 12.5 mM, and 6.25 mM for 24, 48, and 72 h of incubation, respectively. According to the Real-Time-PCR results, 50 mM NaBu after 24 h caused a significant up-regulation in the expression of the miR-21, miR-143, and miR-145 (P<0.05). In 48 h, incubation, 12.5 mM NaBu caused a significant up-regulation in the expression of the miR-21, miR-143, and miR-145 (P<0.05). In treated cells with 6.25 mM NaBu after 72 h of incubation caused a significant up-regulation in the expression of the miR-21, miR-143, and miR-145 compared with untreated cells (P<0.05). The upregulation of miR-21, miR-143, and miR-145 expression are mediated by transcriptional regulation and the activation of this miR promoter is modulated by histone acetylation. The employment of NaBu may represent a promising approach for improving HDACi drug-based therapies for colon cancers.

Lovastatin-Induced Mitochondrial Oxidative Stress Leads to the Release of mtDNA to Promote Apoptosis by Activating cGAS-STING Pathway in Human Colorectal Cancer Cells.

Statins are 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors widely used in the treatment of hyperlipidemia. The inhibition of HMG-CoA reductase in the mevalonate pathway leads to the suppression of cell proliferation and induction of apoptosis. The cyclic GMP-AMP synthase (cGAS) stimulator of the interferon genes (STING) signaling pathway has been suggested to not only facilitate inflammatory responses and the production of type I interferons (IFN), but also activate other cellular processes, such as apoptosis. It has not been studied, however, whether cGAS-STING activation is involved in the apoptosis induced by statin treatment in human colorectal cancer cells. In this study, we reported that lovastatin impaired mitochondrial function, including the depolarization of mitochondrial membrane potential, reduction of oxygen consumption, mitochondrial DNA (mtDNA) integrity, and mtDNA abundance in human colorectal cancer HCT116 cells. The mitochondrial dysfunction markedly induced ROS production in mitochondria, whereas the defect in mitochondria respiration or depletion of mitochondria eliminated reactive oxygen species (ROS) production. The ROS-induced oxidative DNA damage by lovastatin treatment was attenuated by mitochondrial-targeted antioxidant mitoquinone (mitoQ). Upon DNA damage, mtDNA was released into the cytosol and bound to DNA sensor cGAS, thus activating the cGAS-STING signaling pathway to trigger a type I interferon response. This effect was not activated by nuclear DNA (nuDNA) or mitochondrial RNA, as the depletion of mitochondria compromised this effect, but not the knockdown of retinoic acid-inducible gene-1/melanoma differentiation-associated protein 5 (RIG-I/MDA5) adaptor or mitochondrial antiviral signaling protein (MAVS). Moreover, lovastatin-induced apoptosis was partly dependent on the cGAS-STING signaling pathway in HCT116 cells as the knockdown of cGAS or STING expression rescued cell viability and mitigated apoptosis. Similarly, the knockdown of cGAS or STING also attenuated the antitumor effect of lovastatin in the HCT116 xenograft model in vivo. Our findings suggest that lovastatin-induced apoptosis is at least partly mediated through the cGAS-STING signaling pathway by triggering mtDNA accumulation in the cytosol in human colorectal cancer HCT116 cells.

Exploring Mechanism of Actions for Eugenol and Beta-Caryophyllene to Combat Colorectal Cancer Chemotherapy Using Network Pharmacology

This study explores the potential of essential oils, Eugenol (EUG), and Beta-Caryophyllene (BCP) in enhancing the efficacy of the chemotherapeutic drug 5-fluorouracil (5-FU) in treating metastatic colorectal cancer (CRC). Pharmacokinetic assessment through ADMET analysis indicates that EUG and BCP adhere to the rule of five with good bioavailability, ensuring their drug-likeness properties. The study employs a multitarget strategy to reduce drug dosage and enhance effectiveness, testing the compounds on the HCT116 human colorectal cancer cell line. MTT assay revealed in-vitro cytotoxic effects of EUG, BCP, and 5-FU, with a noteworthy reduction in IC50 values observed when combining the compounds, indicating synergistic effects (CI &lt; 1) as depicted in the Fa-CI plot. Network pharmacology-based analysis of the compound-disease-target (C-D-T) network identifies 58, 24, and 49 target proteins for EUG, BCP, and 5-FU, respectively, in metastatic CRC. Venn diagram intersection reveals 11 common target proteins, and the merged C-D-T network highlights 84 target proteins, with 16 selected based on edge count, including HSP90AA1, IGF-1R, ESR1, and CASP3. Molecular docking studies indicate that EUG, BCP, and 5-FU effectively inhibit the core target protein HSP90AA1 within the C-D-T network, suggesting their potential as modulators for CRC metastasis. These findings propose a promising approach for developing drugs targeting specific proteins to mitigate metastasis in colorectal cancer.

Abstract 4715: Azathioprine and Z36 induced cell death in human colorectal cancer HCT-116 and HCT-15 cells

Abstract Rationale and Objectives: Cancer accounts for a huge global health burden and is the third highest cause of death across the globe. Cancer cells are known to have higher basal reactive oxygen species (ROS) levels, owing to their higher metabolism and proliferation. Higher basal ROS in cancer cells made them susceptible to exogenous ROS stimuli that lead to cell death. Therefore, in the present study, we have analyzed the effects of Azathioprine, a glutathione (GSH) inhibitor and an intracellular ROS producer. The effect of Azathioprine was analyzed alone or in combination with a BCL-2 family protein inhibitor Z36, on human colorectal cancer cell lines HCT-116 and HCT-15. Methods: The effects of the drugs have been investigated using various methods including cell viability assay, DNA fragmentation assay, and Annexin V-FITC/PI apoptosis assay. In addition, morphological changes evident in cell death were detected by Giemsa staining. Combination dosage for drug synergistic effects was computed through the use of CompuSyn software. Western blot was performed to detect changes in the expression of cell death-related proteins following drug treatments. Results and conclusion: Azathioprine at a dose of 5 µM has been demonstrated to induce cell death in both HCT116 and HCT15 cells in a concentration and time-dependent manner. On the contrary, Z36, a novel BCLXL inhibitor, has demonstrated similar cell viability results at an even lower dose of 2.5 µM. When both drugs were combined at lower doses, no significant effects were observed on the cell viability of either cell line, demonstrating that the combined treatment has no synergistic or additive effects. This suggests that both drugs do not augment each other and might induce cell death via upregulation of ROS using a similar mechanism. Citation Format: Yousuf Tahir Ali, Mahwish Fatima, Muhammad Areeb Ahmed, Hasan Salman Siddiqi, Azhar Hussain, Mati Ur Rehman. Azathioprine and Z36 induced cell death in human colorectal cancer HCT-116 and HCT-15 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 4715.

Abstract 7221: A compound targeting the circadian clock protein CRY2 enhances therapeutic efficacy of bevacizumab in a colorectal cancer (CRC) xenograft model

Abstract Anti VEGF A antibody Bevacizumab combined with standard chemotherapy has improved outcomes for CRC patients. However, a subset of CRC patients acquires resistance to anti-VEGF treatment and underlying mechanism is poorly understood. Our recent study reported that circadian clock transcription factor BMAL1 drives transcription of VEGFA conferring resistance to bevacizumab treatment. Our rational is to stabilize negative regulator of circadian clock CRY protein to inhibit BMAL1 activity in a negative feedback loop. In this study, we evaluated whether CRY stabilizers SHP656 and SHP1705 in combination with bevacizumab can synergistically enhance anti-tumor effect in CRC mouse models. Methods: In vitro tube formation assay was performed with HUVECs cells to investigate the effect of CRY stabilizer on tube formation. For in vivo experiments, 106 HCT116 human CRC cells were injected subcutaneously into the right flank of 8-week-old nude mice. Mice (5mice/group) were randomized into: A. vehicle (2% carboxymethylcellulose PO 5 days/week; control IgG IP, 2 days/week); B. bevacizumab (5mg/kg IP, twice/week); C. 10mg/kg SHP656; D. 30mg/kg SHP656; E. 30mg/kg SHP1705; F. 10mg/kg SHP656 + bevacizumab; G. 30mg/kg SHP656 + bevacizumab; G. 30mg/kg SHP1705 + bevacizumab. SHP 656 &amp; 1705 was given PO; 5days/week. Tumor volume was measured three times a week. The survival curve was plotted using Kaplan and Meier method and assessed for statistical significance with log-rank test. Results: The in vitro tube formation assay showed significant inhibition of tube formation in HUVEC cells treated with SHP1705 plus bevacizumab compared to treated with bevacizumab alone. In in vivo study, the tumors treated with 30mg/kg SHP1705 + bevacizumab significantly suppressed tumor growth compared to bevacizumab monotherapy (one way-ANOVA, P &amp;lt;0.05). 30mg/kg SHP1705 + bevacizumab significantly improved survival of the mice (Log-rank test, P &amp;lt;0.05). No significant survival benefit was observed with bevacizumab alone. 3/5 mice treated with SHP1705 + bevacizumab showed decreased tumor volume and achieved complete regression for more than 4 months without additional treatment. In combination with bevacizumab, higher dose of SHP656 (30mg/kg) delayed tumor growth and extended survival compared with bevacizumab monotherapy (though did not reach statistical significance) whereas the lower dose of 10mg/kg did not show anti-tumor effect, demonstrating a dose dependent response. Conclusion: Our study shows that CRY stabilizers in combination with bevacizumab significantly enhances anti-tumor efficacy in CRC mouse models. Although mechanism of action of SHP compounds on angiogenesis pathway still needs further investigation, these findings may support development of novel treatment strategies modulating circadian clock to overcome bevacizumab resistance in CRC patients. Citation Format: Jae Ho Lo, Shivani Soni, Goar Smbatyan, Lesly Torres-Gonzalez, Pooja Mittal, Yan Yang, Francesca Battaglin, Priscilla Chan, Yuanzhong Pan, Sandra Algaze, Priya Jayachandran, Karam Ashouri, Alexandra Wong, Wu Zhang, Joshua Millstein, Indrakant K. Singh, Evanthia T. Roussos Torres, Shannon M. Mumenthaler, Steve A. Kay, Heinz-Josef Lenz. A compound targeting the circadian clock protein CRY2 enhances therapeutic efficacy of bevacizumab in a colorectal cancer (CRC) xenograft model [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 7221.

Determination of fatty acid uptake and desaturase activity in mammalian cells by NMR-based stable isotope tracing

BackgroundMammalian cells both import exogenous fatty acids and synthesize them de novo. Palmitate, the end product of fatty acid synthase (FASN) is a substrate for stearoyl-CoA desaturases (Δ-9 desaturases) that introduce a single double bond into fatty acyl-CoA substrates such as palmitoyl-CoA and stearoyl-CoA. This process is particularly upregulated in lipogenic tissues and cancer cells. Tracer methodology is needed to determine uptake versus de novo synthesis of lipids and subsequent chain elongation and desaturation. Here we describe an NMR method to determine the uptake of 13C-palmitate from the medium into HCT116 human colorectal cancer cells, and the subsequent desaturation and incorporation into complex lipids. ResultsExogenous 13C16-palmitate was absorbed from the medium by HCT116 cells and incorporated primarily into complex glycerol lipids. Desaturase activity was determined from the quantification of double bonds in acyl chains, which was greatly reduced by ablation of the major desaturase SCD1. SignificanceThe NMR approach requires minimal sample preparation, is non-destructive, and provides direct information about the level of saturation and incorporation of fatty acids into complex lipids.

P1212 Effects of Enterococcus faecalis-derived Gelatinase E on HCT116 colorectal cancer cells

Abstract Background The leading cause of death in colorectal cancer (CRC) patients is metastasis to crucial organs, such as the lung, brain and liver. The tumour microenvironment (TME) influences metastasis heavily. One important component in the TME of CRC is the microbiota. Microbiota can affect several pathways related to the origin of metastasis and reorganization of the extracellular matrix. One of the possible contributors to early CRC metastasis is Enterococcus faecalis. E. faecalis produces Gelatinase E (GelE), a quorum-sensing protein with collagenolytic properties. The primary goal of our study was to determine the effect of GelE on CRC behaviour, and especially on migration and invasion in HCT-116 human CRC cells. Moreover, we aimed to uncover the underlying pathways by which GelE influences CRC cells. Methods Extracellular GelE was purified from E. faecalis strain V583 from the culture medium. HCT-116 cells were cultured and exposed to different concentrations of GelE. We performed a viability assay using CCK-8 to assess potential toxicity of GelE. To test effects of GelE on collagen structure, we measured stiffness of collagen-I. A transwell assay was used to assess the influence of GelE on invasive capacity of cells through a collagen-I matrix. GelE exposed cells were assessed for shape and motility markers using immunofluorescent staining for β-catenin (cell shape) and loss of E-cadherin (cell motility marker). For mechanistic insight of GelE exposure on HCT116, we performed proteomics analysis on the cells. Results GelE treatment did not affect relative cell viability of HCT116 cells up to a concentration of 100 μg/ml. Exposure to GelE caused a concentration-dependent increase in HCT-116 cell invasion through collagen-I. The immunostainings showed a downregulation of E-cadherin, indicating an induction of cell motility. Immunostaining for β-catenin showed a statistically significant effect on cell shape, becoming more elongated, an additional indication of cell motility. Proteomics showed possible mechanistic pathways that explain the increased motility including activation of the SMAD pathway, RhoGTPAse activation and activation the urokinase-plasminogen system. Reactome database analysis on the proteomics data also revealed an increase in cell-cycle related pathways. Conclusion Our results indicate that E. faecalis-derived GelE drives HCT-116 invasion with an elongated motility. Therefore, drugs inhibiting the activity of GelE could decrease the risk of metastasis in patients with a high E. faecalis V583 abundance in the TME.

Six bufadienolides derivatives are the main active substance against human colorectal cancer HCT116 cells of Huachansu injection

BackgroundHuachansu injection (HCS) is an aqueous extract preparation of Traditional Chinese Medicine (TCM) toad skin (Bufo melanosticus or B. bufo gargarizans). As a national second-class and self-developed TCM preparation, it is widely used to treat human colorectal cancer (CRC), yet its substantial toxic side effects, such as vascular irritation reaction, drug fever, and allergic reactions, pose a considerable challenge during clinical use. In-depth research on the material basis of HCS' traditional efficacy is essential for developing more effective and less toxic medicine. Identifying the main components responsible for the efficacy of HCS is crucial in determining its material basis and explaining any adverse reactions. PurposeThe purpose of this study is to clarify the main active components of HCS as a growth inhibitory agent against CRC HCT116 cells and to further understand the material basis of its anti-CRC properties. MethodsSulforhodamine B (SRB) assay was used to screen the compound with strong inhibitory activity against HCT116 cells from 44 compounds isolated from aqueous extracts of toad skin (B. melanosticus). The screened compounds as standard and MeOH extracts from HCS were determined by HPLC coupled with triple quadrupole mass spectrometry. The partial MeOH extract was subjected to HPLC system using solvents in a gradient of increasing polarity, yielding 12 fractions in total (HCS1 to HCS12). Besides, the screened active compounds were knocked out from HCS to obtain a fraction as a negative control, and the knocked-out components were collected as one fraction using semi-preparative HPLC. Those fractions were submitted to HPLC-MS/MS or HPLC-DAD system to determine the presence or absence of the screened compounds. In addition, cytotoxicity of those prepared fractions against CRC HCT116 cells was evaluated to determine the effect of the screened compounds in the anti-CRC of HCS. ResultsSix compounds, namely arenobufagin, telocinobufagin, gamabufalin, hellebrigenin, 19-hydroxylbufagin and argentinogenin, were screened for their inhibitory activity (with an IC50 value of less than 400 nM), and were present in HCS at a total-mass-percentage of 1.35×10−3 % in HCS MeOH extract. In addition, those 6 compounds were mainly distributed in HCS8, which also showed the strongest inhibitory activity against HCT116 cells. And the results of multicomponent knockout assay indicated the negative control lost its anti-CRC activity significantly, while the activity can be restored after those 6 compounds were added to the negative control. ConclusionsThose six bufadienolides derivatives are responsible for the anti-CRC HCT116 cells activity of HCS, and are the main components of HCS on anti-CRC. Through this research, we can more clearly understand the main anti-CRC active components in HCS, and the work also lays the foundation for the development of more effective and less toxic medicine from HCS.

Recombinant Methioninase Decreased the Effective Dose of Irinotecan by 15-fold Against Colon Cancer Cells: A Strategy for Effective Low-toxicity Treatment of Colon Cancer.

Irinotecan (IRN), a topoisomerase I inhibitor and pro-drug of SN-38, is first-line treatment of colon cancer as part of FOLFIRI and FOLFOXIRI combination chemotherapy. However, IRN causes dose-limiting adverse events such as neutropenia and diarrhea. Dose reductions are sometimes required, which reduce efficacy. Recombinant methioninase (rMETase) targets the fundamental basis of cancer, methionine addiction, known as the Hoffman effect, and enhances the efficacy of numerous chemotherapy drugs. The present study determined the efficacy of rMETase when administered in combination with IRN. Cell viability was assessed by cultivating the HCT-116 human colorectal cancer cell line in 96-well plates at 1×103 cells per well in Dulbecco's modified Eagle's medium (DMEM). Subsequently, HCT-116 cells were treated with increasing concentrations of SN-38, the active form of IRN, ranging from 0.5 nM to 32 nM, and/or rMETase ranging from 0.125 to 8 U/ml. After treatment for 72 h, the half-maximal inhibitory concentration (IC50) of SN-38 alone and rMETase alone for HCT-116 cells were determined. Using the IC50 concentration of rMETase, we determined the IC50 of SN-38 in combination with rMETase. Cell viability was determined with the cell-counting Kit-8 with the WST-8 reagent.. The IC50 of rMETase alone for the HCT-116 cells was 0.55 U/ml, and the IC50 of IRN (SN-38) alone was 3.50 nM. rMETase at 0.55 U/ml lowered the IC50 of SN-38 to 0.232 nM (p<0.0001), a 15-fold reduction. rMETase and IRN are strongly synergistic, giving rise to the possibility of lowering the effective dose of IRN for the treatment of patients with colon cancer, thereby reducing its severe toxicity. This new strategy will allow more patients with cancer to be effectively treated with IRN.

Anticancer and anti-angiogenic activities of mannooligosaccharides extracted from coconut meal on colorectal carcinoma cells in vitro

Colorectal carcinoma (CRC) is one of the most common malignancies, though there are no effective therapeutic regimens at present. This study aimed to investigate the inhibitory effects of mannooligosaccharides extracted from coconut meal (CMOSs) on the proliferation and migration of human colorectal cancer HCT116 cells in vitro. The results showed that CMOSs exhibited significant inhibitory activity against HCT116 cell proliferation in a concentration-dependent manner with less cytotoxic effects on the Vero normal cells. CMOSs displayed the ability to increase the activation of caspase-8, –9, and –3/7, as well as the generation of reactive oxygen species (ROS). Moreover, CMOSs suppressed HCT116 cell migration in vitro. Interestingly, treatment of human microvascular endothelial cells (HMVECs) with CMOSs resulted in the inhibition of cell proliferation, cell migration, and capillary-like tube formation, suggesting its anti-vascular angiogenesis. In summary, the results of this study indicate that CMOSs could be a valuable therapeutic candidate for CRC treatment.

1,8-Dihydroxy-3-methoxy-anthraquinone inhibits tumor angiogenesis through HIF-1α downregulation

Photorhabdus luminescens is a gram-negative bioluminescent bacterium known as an intestinal bacterium that coexists in the digestive tract of insect-pathogenic nematodes. As part of our ongoing exploration to identify bioactive compounds from diverse natural resources, the chemical analysis of the cultures of P. luminescens KACC 12254 via LC/MS and TLC-based analyses enabled the isolation and identification of a major fluorescent compound. Its chemical structure was elucidated as 1,8-dihydroxy-3-methoxyanthraquinone (DMA) using HR-ESI-MS and NMR analysis. In this study, we conducted comprehensive investigations utilizing human colorectal cancer HCT116 cells, human umbilical cord vascular endothelial cells (HUVECs), and zebrafish embryos to assess the potential benefits of DMA in suppressing tumor angiogenesis. Our results convincingly demonstrate that DMA effectively suppresses the stability of hypoxia-inducible factor-1α (HIF-1α) protein and its target genes without inducing any cytotoxic effects. Furthermore, DMA demonstrates the ability to inhibit HIF-1α transcriptional activation and mitigate the production of reactive oxygen species (ROS). In our in vitro experiments, DMA exhibits notable inhibitory effects on VEGF-mediated tube formation, migration, and invasion in HUVECs. Additionally, in vivo investigations using zebrafish embryos confirm the antiangiogenic properties of DMA. Notably, DMA does not exhibit any adverse developmental or cardiotoxic effects in the in vivo setting. Moreover, we observe DMA's capability to restrain tumor growth through the downregulation of PI3K/AKT and c-RAF/ERK pathway. Collectively, these compelling findings underscore DMA's potential as a promising therapeutic candidate for targeted intervention against HIF-1α and angiogenesis in cancer treatment.

MHY446 induces apoptosis via reactive oxygen species-mediated endoplasmic reticulum stress in HCT116 human colorectal cancer cells

This study investigated the potential of a newly synthesized histone deacetylase (HDAC) inhibitor, MHY446, in inducing cell death in HCT116 colorectal cancer cells and compared its activity with that of suberoylanilide hydroxamic acid (SAHA), a well-known HDAC inhibitor. The results showed that MHY446 increased the acetylation of histones H3 and H4 and decreased the expression and activity of HDAC proteins in HCT116 cells. Additionally, MHY446 was confirmed to bind more strongly to HDAC1 than HDAC2 and inhibit its activity. In vivo experiments using nude mice revealed that MHY446 was as effective as SAHA in inhibiting HCT116 cell-grafted tumor growth. This study also evaluated the biological effects of MHY446 on cell survival and death pathways. The reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) confirmed that ROS play a role in MHY446-induced cell death by reducing poly(ADP-ribose) polymerase cleavage. MHY446 also induced cell death via endoplasmic reticulum (ER) stress by increasing the expression of ER stress-related proteins. NAC treatment decreased the expression of ER stress-related proteins, indicating that ROS mediate ER stress as an upstream signaling pathway and induce cell death. While MHY446 did not exhibit superior HDAC inhibition efficacy compared to SAHA, it is anticipated to provide innovative insights into the future development of therapeutic agents for human CRC by offering novel chemical structure-activity relationship-related information.