Human Colorectal Cancer Cell Lines Research Articles

Selective but not pan-CDK inhibition abrogates 5-FU-driven tissue factor upregulation in colon cancer

Thromboembolic events are complications in cancer patients and hypercoagulability has been linked to the tissue factor (TF) pathway, making this an attractive target. Here, we investigated the effects of chemotherapeutics and CDK inhibitors (CDKI) abemaciclib/palbociclib (CDK4/6), THZ-1 (CDK7/12/13), and dinaciclib (CDK1/2/5/9) alone and in combination regimens on TF abundance and coagulation. The human colorectal cancer (CRC) cell line HROC173 was treated with 5-FU or gemcitabine to stimulate TF expression. TF+ cells were sorted, recultured, and re-analyzed. The effect of treatment alone or in combination was assessed by functional assays. Low-dose chemotherapy induced a hypercoagulable state and significantly upregulated TF, even after reculture without treatment. Cells exhibited characteristics of epithelial-mesenchymal transition, including high expression of vimentin and mucin. Dinaciclib and THZ-1 also upregulated TF, while abemaciclib and palbociclib downregulated it. Similar results were observed in coagulation assays. The same anticoagulant activity of abemaciclib was seen after incubation with peripheral immune cells from healthy donors and CRC patients. Abemaciclib reversed 5-FU-induced TF upregulation and prolonged clotting times in second-line treatment. Effects were independent of cytotoxicity, senescence, and p27kip1 induction. TF-antibody blocking experiments confirmed the importance of TF in plasma coagulation, with Factor XII playing a minor role. Short-term abemaciclib counteracts 5-FU-induced hypercoagulation and eventually even prevents thromboembolic events.

Abstract P52: Combination of 5-fluorouracil and Menadione Exerts Synergistic Effect on Colorectal Cancer Cells by Targeting Wnt/β-catenin Signaling Pathway

Abstract Colorectal cancer is the third most common type of cancer and the second most in terms of mortality rate worldwide. 5-fluorouracil (5-FU), the fluoropyrimidine drug, that interferes with DNA replication and repair processes, is the first-line-of-treatment against colorectal cancer. However, cells gain resistance over time and relapses occur upon continuous 5-FU therapy. Interestingly, 5-FU promotes stemness in colorectal cancer via Wnt signaling pathway which is critical for its progression. Studies have pointed out the possibility of using a Wnt signaling inhibitor along with 5-FU as a better strategy to overcome the poor outcomes of current 5-FU based therapies. We have previously shown that menadione (vitamin K3) suppresses Wnt signaling pathway in colorectal cancer cells. In the present study, we attempted to evaluate if the combination of menadione and 5-FU can exert a synergistic effect in the human colorectal cancer cell lines HCT116 and SW620. Analysis of the cell viability assay results using CompuSyn software confirmed that the combination indeed acts synergistically. The combination efficiently downregulated the expression of the Wnt signal transducer protein, β-catenin, and the expression of other proteins in the pathway such as phospho-GSK3β in the cell lines HCT116 and SW620. Docking of the individual drugs and their combination on β-catenin using Autodock Vina showed that 5-FU and menadione in combination bind to key protein-protein interaction (PPI) sites of β-catenin whereby they may inhibit β-catenin-TCF interaction or activate the β-catenin destruction complex. Taken together, our data possibly explains that the synergistic action of 5-FU and menadione in colorectal cancer cells may be due to the simultaneous binding of the two drugs to multiple PPI sites thereby blocking the activity of β-catenin. Citation Format: Vidya P Warrier, Sankaran Venkatachalam, Sakthivel Ramasamy, M Michael Gromiha, Devarajan Karunagaran. Combination of 5-fluorouracil and Menadione Exerts Synergistic Effect on Colorectal Cancer Cells by Targeting Wnt/β-catenin Signaling Pathway [abstract]. In: Proceedings of Frontiers in Cancer Science; 2023 Nov 6-8; Singapore. Philadelphia (PA): AACR; Cancer Res 2024;84(8_Suppl):Abstract nr P52.

UBXN11 Predicts as a Poor Index for Colorectal Cancer and Contributes to the Tumorigenesis by Activating NF-κB Signaling.

The complex mechanisms of colorectal cancer (CRC) pathogenesis and progression remain poorly understood. This study endeavors to unravel the role of UBXN11within the context of CRC. UBXN11 expression level in CRC, stomach adenocarcinoma and esophageal carcinoma, and the overall survival in corresponding cancers were analyzed using UALCAN database. Human CRC cell lines and xenograft mouse model with UBXN11 overexpression were established to investigate the pathological role of UBXN11 in CRC progression. Luciferase assay, qPCR, and Western blot were performed to dissect the interaction between UBXN11 and NF-κB signaling. Heightened UBXN11 expression was observed in various digestive tract tumors, which was positively correlated with the reduced overall survival rates in CRC patients. Overexpression of UBXN11 significantly enhanced CRC cell proliferation in vitro and promoted tumor growth in vivo. Mechanistically, UBXN11 promoted CRC tumorigenesis through increasing the activation of NF-κB signaling pathway. This study underscores the pivotal role of UBXN11 in CRC progression and paves the way for novel therapeutic strategies for CRC treatment.

Dexmedetomidine promotes colorectal cancer progression via Piwil2 signaling.

α2-adrenoceptor agonist dexmedetomidine (DEX) has been reported to promote tumorigenesis. Stem-cell protein Piwil2 is associated with cancer progression. Whether Piwil2 plays a role in tumor-promoting effects of DEX is unknown. We examined the expression of Piwil2 in human colorectal cancer (CRC) cell lines with/without DEX treatment. We also studied the roles of Piwil2 in proliferation, invasion, migration, as well as expressions of epithelial-mesenchymal transition (EMT)-related proteins in DEX-treated in vitro and in vivo CRC models. And the experiments with genetic and pharmacological treatments were conducted to investigate the underlying molecular mechanism. RNA-sequencing (RNA-seq) analysis found Piwil2 is one of most upregulated genes upon DEX treatment in CRC cells. Furthermore, Piwil2 protein levels significantly increased in DEX-treated CRC cancer cells, which promoted proliferation, invasion, and migration in both CRC cell lines and human tumor xenografts model. Mechanistically, DEX increased nuclear factor E2-related factor 2 (Nrf2) expression, which enhanced Piwil2 transcription via binding to its promoter. Furthermore, in vitro experiments with Piwil2 knockdown or Siah2 inhibition indicated that DEX promoted EMT process and tumorigenesis through Siah2/PHD3/HIF1α pathway. The experiments with another α2-adrenoceptor agonist Brimonidine and antagonists yohimbine and atipamezole also suggested the role of Piwil2 signaling in tumor-promoting effects via an α2 adrenoceptor-dependent manner. DEX promotes CRC progression may via activating α2 adrenoceptor-dependent Nrf2/Piwil2/Siah2 pathway and thus EMT process. Our work provides a novel insight into the mechanism underlying tumor-promoting effects of α2-adrenoceptor agonists.

In vitro study of radiosensitivity in colorectal cancer cell lines associated with Lynch syndrome.

Lynch syndrome patients have an inherited predisposition to cancer due to a deficiency in DNA mismatch repair (MMR) genes which could lead to a higher risk of developing cancer if exposed to ionizing radiation. This pilot study aims to reveal the association between MMR deficiency and radiosensitivity at both a CT relevant low dose (20 mGy) and a therapeutic higher dose (2 Gy). Human colorectal cancer cell lines with (dMMR) or without MMR deficiency (pMMR) were analyzed before and after exposure to radiation using cellular and cytogenetic analyses i.e., clonogenic assay to determine cell reproductive death; sister chromatid exchange (SCE) assay to detect the exchange of DNA between sister chromatids; γH2AX assay to analyze DNA damage repair; and apoptosis analysis to compare cell death response. The advantages and limitations of these assays were assessed in vitro, and their applicability and feasibility investigated for their potential to be used for further studies using clinical samples. Results from the clonogenic assay indicated that the pMMR cell line (HT29) was significantly more radio-resistant than the dMMR cell lines (HCT116, SW48, and LoVo) after 2 Gy X-irradiation. Both cell type and radiation dose had a significant effect on the yield of SCEs/chromosome. When the yield of SCEs/chromosome for the irradiated samples (2 Gy) was normalized against the controls, no significant difference was observed between the cell lines. For the γH2AX assay, 0, 20 mGy and 2 Gy were examined at post-exposure time points of 30 min (min), 4 and 24 h (h). Statistical analysis revealed that HT29 was only significantly more radio-resistant than the MLH1-deficient cells lines, but not the MSH2-deficient cell line. Apoptosis analysis (4 Gy) revealed that HT29 was significantly more radio-resistant than HCT116 albeit with very few apoptotic cells observed. Overall, this study showed radio-resistance of the MMR proficient cell line in some assays, but not in the others. All methods used within this study have been validated; however, due to the limitations associated with cancer cell lines, the next step will be to use these assays in clinical samples in an effort to understand the biological and mechanistic effects of radiation in Lynch patients as well as the health implications.

Nuclear lipid droplets in Caco2 cells originate from nascent precursors and in situ at the nuclear envelope

Intestinal epithelial cells convert excess fatty acids into triglyceride (TAG) for storage in cytoplasmic lipid droplets and secretion in chylomicrons. Nuclear lipid droplets (nLDs) are present in intestinal cells but their origin and relationship to cytoplasmic TAG synthesis and secretion is unknown. nLDs and related lipid-associated promyelocytic leukemia structures (LAPS) were abundant in oleate-treated Caco2 but less frequent in other human colorectal cancer cell lines and mouse intestinal organoids. nLDs and LAPS in undifferentiated oleate-treated Caco2 cells harbored the phosphatidate phosphatase Lipin1, its product diacylglycerol, and CTP:phosphocholine cytidylyltransferase (CCT)α. CCTα knockout Caco2 cells had fewer but larger nLDs, indicating a reliance on de novo PC synthesis for assembly. Differentiation of Caco2 cells caused large nLDs and LAPS to form regardless of oleate treatment or CCTα expression. nLDs and LAPS in Caco2 cells did not associate with apoCIII and apoAI and formed dependently of microsomal triglyceride transfer protein expression and activity, indicating they are not derived from endoplasmic reticulum luminal LDs precursors. Instead, undifferentiated Caco2 cells harbored a constitutive pool of nLDs and LAPS in proximity to the nuclear envelope that expanded in size and number with oleate treatment. Inhibition of TAG synthesis did affect the number of nascent nLDs and LAPS but prevented their association with promyelocytic leukemia protein, Lipin1α, and diacylglycerol, which instead accumulated on the nuclear membranes. Thus, nLD and LAPS biogenesis in Caco2 cells is not linked to lipoprotein secretion but involves biogenesis and/or expansion of nascent nLDs by de novo lipid synthesis.

Effects of down-regulated carbonic anhydrase 8 on cell survival and glucose metabolism in human colorectal cancer cell lines.

Carbonic anhydrase 8 (CA8) is a member of the α-carbonic anhydrase family but does not catalyze the reversible hydration of carbon dioxide. In the present study, we examined the effects of CA8 on two human colon cancer cell lines, SW480 and SW620, by suppressing CA8 expression through shRNA knockdown. Our results showed that knockdown of CA8 decreased cell growth and cell mobility in SW620 cells, but not in SW480 cells. In addition, downregulated CA8 resulted in a significant decrease of glucose uptake in both SW480 and SW620 cells. Interestingly, stable downregulation of CA8 decreased phosphofructokinase-1 expression but increased glucose transporter 3 (GLUT3) levels in SW620 cells. However, transient downregulation of CA8 fails to up-regulate GLUT3 expression, indicating that the increased GLUT3 observed in SW620-shCA8 cells is a compensatory effect. In addition, the interaction between CA8 and GLUT3 was evidenced by pull-down and IP assays. On the other hand, we showed that metformin, a first-line drug for type II diabetes patients, significantly inhibited cell migration of SW620 cells, depending on the expressions of CA8 and focal adhesion kinase. Taken together, our data demonstrate that when compared to primary colon cancer SW480 cells, metastatic colon cancer SW620 cells respond differently to downregulated CA8, indicating that CA8 in more aggressive cancer cells may play a more important role in controlling cell survival and metformin response. CA8 may affect glucose metabolism- and cell invasion-related molecules in colon cancer, suggesting that CA8 may be a potential target in future cancer therapy.

Antioxidant Activity and Antitumor Potential of Hedyotis chrysotricha Extract in Human Colorectal Cancer and Breast Cancer Cell Lines

Background: Cancer is a serious disease severely endangering human health and life in the world in the world, and conventional anticancer drugs have frequently suffered from severe side effects and resistance. Therefore, developing novel and effective therapeutic strategies is urgently needed. As a Chinese herbal medicine with important medical values, Hedyotis chrysotricha has been suggested to be useful for the treatment of many diseases, especially cancer. Objective: Our aim was to investigate the antioxidant and antitumor activities of the phytochemical extracts of H. chrysotricha. Methods: 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay was applied to determine antioxidant property. 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay, wound healing assay, transwell matrix assay, flow cytometry and cell morphology were established to observe anti-proliferative, anti-migration, anti-invasion and apoptosis induction effects. The intracellular reactive oxygen species generation was detected by reactive oxygen species detection assay. Results: The ethyl acetate fraction showed promising antioxidant activity with IC50 of 98.67±0.49 μg/ml, and petroleum ether fraction exhibited the most potent antiproliferative effect on various human cancer cell lines, especially MDA-MB-231 (IC50 = 8.90±1.23 μg/ml) and HCT-116 (IC50 = 9.69±3.69 μg/ml) cancer cells. Further investigation revealed that the petroleum ether fraction suppressed the proliferation, migration and invasion of the cancer cells significantly. Additionally, it promoted cell apoptosis by increasing reactive oxygen species levels. Conclusion: H. chrysotricha extract possessed excellent antioxidant and antitumor activities. Therefore, it could be useful as a source of antioxidants and compounds for cancer therapy.

Rescue of Methionine Dependence by Cobalamin in a Human Colorectal Cancer Cell Line.

Methionine dependence is a characteristic of most cancer cells where they are unable to proliferate when the essential amino acid methionine is replaced with its precursor homocysteine in the growing media. Normal cells, on the other hand, thrive under these conditions and are referred to as methionine-independent. The reaction that adds a methyl group from 5-methyltetrahydrofolate to homocysteine to regenerate methionine is catalyzed by the enzyme methionine synthase with the cofactor cobalamin (vitamin B12). However, decades of research have shown that methionine dependence in cancer is not due to a defect in the activity of methionine synthase. Cobalamin metabolism has been tied to the dependent phenotype in rare cell lines. We have identified a human colorectal cancer cell line in which the cells regain the ability to proliferation in methionine-free, L-homocystine-supplemented media when cyanocobalamin is supplemented at a level of 1 µg/mL. In human SW48 cells, methionine replacement with L-homocystine does not induce any measurable increase in apoptosis or reactive oxygen species production in this cell line. Rather, proliferation is halted, then restored in the presence of cyanocobalamin. Our data show that supplementation with cyanocobalamin prevents the activation of the integrated stress response (ISR) in methionine-deprived media in this cell line. The ISR-associated cell cycle arrest, characteristic of methionine-dependence in cancer, is also prevented, leading to the continuation of proliferation in methionine-deprived SW48 cells with cobalamin. Our results highlight differences between cancer cell lines in the response to cobalamin supplementation in the context of methionine dependence.

Abstract 2093: Co-treatment with KRAS G12D inhibitor MRTX1133 plus TTFields against human pancreatic and Colorectal cancer cell lines results in synergistic up-regulation of cleaved PARP in KRAS G12D & unexpectedly in KRAS G12V as well

Abstract Background: Both colorectal and pancreatic cancers are major global health issues and among deadliest cancers with great disease burden. The most commonly mutated oncogenic alteration in human cancers is KRAS, which is prevalent in pancreatic malignancies. The KRAS G12D mutation subtype is present in more than 40% of pancreatic ductal adenocarcinoma (PDAC). To this date there is no available targeted therapy options for patients with KRAS subtype mutations. MRTX1133 has been identified as a non-covalent, potent, and selective inhibitor of KRASG12D. This small molecule inhibitor has been shown to suppress KRASG12D signaling in cells and in vivo. Tumor Treating Fields (TTFields) therapy is a novel approach to treating cancer, the electric fields alter the behavior of cancer cells and prevent them from growing and dividing. We hypothesize that the co-application of MRTX1133 with TTFields will enhance the effects of MRTX1133 in PDAC and colorectal cancer (CRC). Martials and Methods: PDAC cell line CFPAC1 with KRAS G12 V mutation and LS513 CRC cell line with KRAS G12D Mutation were treated with same dose of MRTX1133 (500 nM) and were co-treated with 150kHz TTFields. After 48 hours western blot was used to probe for cleaved PARP, cleaved C3, phosphor-ERK and DUSP6. Results: In both KRAS G12D & KRAS G12V cell lines, synergistic upregulation of cPARP was observed following 48-hour co-treatment. Synergistic inhibition of pERK happened in KRAS G12D cell line but no change in pERK level following TTFields or MRTX1133 treatment was seen. Upregulation of cC3 in KRAS G12D happened in only co-treatment conditions. DUSP6 levels increased following MRTX1133 treatment in KRAS G12V cell line. Conclusions: The surprising synergistic upregulation of cPARP in both KRAS G12V and G12D cells following co-treatment of KRAS G12D inhibitor MRTX1133 and TTFields can bring hope for other KRAS mutation subtypes as well as G12D. the increase in cPARP in KRAS G12V with no effect on pERK is particularly interesting and demonstrates the need of more studies to investigate the mechanisms of this synergy. Citation Format: Vida Tajiknia, Praveen Srinivasan, Maximilian PInho-Schwermann, William MacDonald, Connor Purcell, Wafik El-Deiry. Co-treatment with KRAS G12D inhibitor MRTX1133 plus TTFields against human pancreatic and Colorectal cancer cell lines results in synergistic up-regulation of cleaved PARP in KRAS G12D & unexpectedly in KRAS G12V as well [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 2093.

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 1218: CDK9 inhibitors modulate the transcriptional landscape of colorectal cancer to suppress MAPK signaling and synergizes with BRAF inhibitors to treat BRAF-mutant colorectal cancer

Abstract Background: Colorectal cancer (CRC) is the second leading cause of cancer deaths in the US, and it remains a significant public health burden. Metastatic CRC (mCRC) is usually treated with combination chemotherapy and targeted therapy regimens, but eventually becomes chemotherapy refractory. Thus, novel and more effective treatments for mCRC are urgently needed. Cyclin-dependent kinase 9 (CDK9) is a key activator of RNA Pol II transcription and promotes the expression of many cancer driver genes, making CDK9 a promising target for cancer therapy. Methods: Human CRC cell lines, patient-derived organoids (PDOs), cell line xenografts, and patient-derived xenografts were used to investigate the efficacy and mechanisms of action of the CDK9 inhibitors AZD4573, enitociclib, and NVP-2, as well as the BRAF inhibitors encorafenib and dabrafenib. In vitro viability was measured by chemical cell proliferation assays and in vivo tumor sizes were measured by calipers. In vitro mechanisms of action were assessed by RNA sequencing, real time polymerase chain reaction, and Western blotting. In vivo mechanisms of action were assessed by immunohistochemistry. Results: CDK9 inhibitors potently inhibited CRC cells and PDOs. In contrast to hematologic malignancies, we did not observe consistent suppression of the oncogenes c-MYC and MCL-1 by CDK9 inhibitor treatment. Instead, CDK9 inhibitors suppressed several other key cancer pathways in CRC, such as MAPK, mTOR, and PI3K signaling pathways. Importantly, multiple targets within the MAPK pathway were strongly suppressed, including EGFR, KRAS, and BRAF. We hypothesized that combination treatment with CKD9 inhibitors and MAPK pathway inhibitors can synergistically treat CRC. As proof-of-concept, we investigated the combination of CDK9 and BRAF inhibitors in models of BRAF-mutant CRC, a particularly aggressive type of CRC. We found this combination to synergistically suppress CRC growth in vitro and in vivo. Compared to single agents, combination treatment led to significantly stronger induction of apoptosis and suppression of MAPK pathway signaling. Our results suggest that concurrent treatment with CDK9 inhibitors plus established MAPK pathway inhibitors, such as BRAF inhibitors, can significantly improve upon single agent treatment. Conclusions: We have found CDK9 inhibitors to potently suppress CRC growth and survival through a unique mechanism of action, by vertical suppression of the MAPK signaling pathway. We demonstrate that CDK9 inhibitors can synergize with BRAF inhibitors in the treatment of BRAF-mutant CRC models. Thus, CDK9 inhibitors are a promising class of drugs warranting further investigation, including early-phase clinical trials, in mCRC. Citation Format: Chaoyuan Kuang, Ning Wei, Mahshid Mohammadi, Muzaffer A. Bhat, Terence Li, Priyanka Patil, Othon Wiltz, Renee Huang, Kohtaro Ooka, Melanie Quintal, Edward Chu. CDK9 inhibitors modulate the transcriptional landscape of colorectal cancer to suppress MAPK signaling and synergizes with BRAF inhibitors to treat BRAF-mutant colorectal cancer [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 1218.

Abstract 1952: Co-alterations in PIK3CA and ARID1A lead to enhanced sensitivity to PI3K inhibition

Abstract Background: There is increasing interest in developing precision medicine strategies for cancers with PIK3CA mutations. Co-alterations in PIK3CA and ARID1A (AD) occur in ~1% of all cancers. Previously, patients with co-alterations in PIK3CA and AD have shown both an improved objective response rate and improved progression free survival following copanlisib (cop) treatment compared to cancers with PIK3CA mutations and wild-type AD. Here we evaluate potential mechanisms for this enhanced clinical benefit. Methods: AD was knocked out in SW48 and SW48PIK3CA-H1047R (SW48PK) human 2D colorectal cancer cell lines using CRISPR (SW48AD; SW48PKAD). Knockouts were confirmed using PCR genotyping, amplicon sequencing, and western blot (WB). A cell proliferation assay (WST-1) was performed at increasing doses of cop for 48hrs to determine cell viability. WBs were performed at 6hrs and 24hrs after cop treatment to determine levels of phosphorylation of AKT, S6, and 4EBP1 and levels of apoptosis-related proteins (MCL-1, BCL-xL, BCL-2, PARP). Athymic nude mice were flank injected with SW48PK and SW48PKAD and treated with cop (10mg/kg in PEG400/acidified water (0.1N HCl, pH 3.5; 20/80, v/v) or vehicle for 25 days or until moribund. Results: WST-1 assay showed highest sensitivity to cop in SW48PKAD cells compared to SW48, SW48PK and SW48AD. At 10nM (p=0.01), there was a significant difference in cell viability between SW48PK and SW48PKAD. No significant difference was seen in the phosphorylation (p) of AKT, S6, or 4EBP1 between SW48PK and SW48PKAD. Expression of MCL-1 protein decreased in SW48PKAD compared to SW48PK. No difference was seen in levels of BCL-xL and BCL-2. On treatment with cop, there was a greater reduction in pS6 in SW48PKAD at 24 hours compared to SW48PK, but no significant difference in pAKT and p4EBP1. There was a gradual increase in MCL-1, BCL-xL, and cleaved PARP in SW48PKAD overtime following cop treatment compared to SW48PK. In vivo, untreated SW48PKAD tumors grew more quickly than the SW48PK tumors (8-fold increase in tumor size in SW48PKAD compared to 5-fold increase in SW48PK by day 25, p=0.06). SW48PKAD mice had significant tumor reduction (p=0.002) on cop treatment by day 25; however, SW48PK mice did not. Conclusions: ARID1A loss along with PIK3CA mutation leads to greater PI3K inhibition response most likely due to enhanced induction of apoptosis. Further confirmation of this enhanced sensitivity is required with better in vitro models such as patient-derived cancer organoids. Citation Format: Shirsa Udgata, Jordan N. Stoecker, Anna L. Lippert, Cheri A. Pasch, Dustin A. Deming. Co-alterations in PIK3CA and ARID1A lead to enhanced sensitivity to PI3K inhibition [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 1952.

Identifying regulators of aberrant stem cell and differentiation activity in colorectal cancer using a dual endogenous reporter system

Aberrant stem cell-like activity and impaired differentiation are central to the development of colorectal cancer (CRC). To identify functional mediators of these key cellular programs, we engineer a dual endogenous reporter system by genome-editing the SOX9 and KRT20 loci of human CRC cell lines to express fluorescent reporters, broadcasting aberrant stem cell-like and differentiation activity, respectively. By applying a CRISPR screen targeting 78 epigenetic regulators with 542 sgRNAs to this platform, we identify factors that contribute to stem cell-like activity and differentiation in CRC. Perturbation single cell RNA sequencing (Perturb-seq) of validated hits nominate SMARCB1 of the BAF complex (also known as SWI/SNF) as a negative regulator of differentiation across an array of neoplastic colon models. SMARCB1 is a dependency and required for in vivo growth of human CRC models. These studies highlight the utility of biologically designed endogenous reporter platforms to uncover regulators with therapeutic potential.

Detailed survey of an in vitro intestinal epithelium model by single-cell transcriptomics

The co-culture of two adult human colorectal cancer cell lines, Caco-2 and HT29, on Transwell is commonly used as an invitro gut mimic, yet the translatability of insights from such a system to adult human physiological contexts is not fully characterized. Here, we used single-cell RNA sequencing on the co-culture to obtain a detailed survey of cell type heterogeneity in the system and conducted a holistic comparison with human physiology. We identified the intestinal stem cell-, transit amplifying-, enterocyte-, goblet cell-, and enteroendocrine-like cells in the system. In general, the co-culture was fetal intestine-like, with less variety of gene expression compared to the adult human gut. Transporters for major types of nutrients were found in the majority of the enterocytes-like cells in the system. TLR 4 was not expressed in the sample, indicating that the co-culture model is incapable of mimicking the innate immune aspect of the human epithelium.

Microplastics role in cell migration and distribution during cancer cell division

Amidst the global plastic pollution crisis, the gastrointestinal tract serves as the primary entry point for daily exposure to micro- and nanoplastics. We investigated the complex dynamics between polystyrene micro- and nanoplastics (PS-MNPs) and four distinct human colorectal cancer cell lines (HT29, HCT116, SW480, and SW620). Our findings revealed a significant size- and concentration dependent uptake of 0.25, 1, and 10 μm PS-MNPs across all cell lines, with HCT116 cells exhibiting the highest uptake rates. During cell division, particles were distributed between mother and daughter cells. Interestingly, we observed no signs of elimination from the cells. Short-term exposure to 0.25 μm particles significantly amplified cell migration, potentially leading to pro-metastatic effects. Particles demonstrated high persistence in 2D and 3D cultures, and accumulation in non-proliferating parts of spheroids, without interfering with cell proliferation or division. Our study unveils the disturbing fact of the persistence and bioaccumulation of MNPs in colorectal cancer cell lines, key toxicological traits under REACH (Regulation concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals). Our observations underscore the potential of MNPs as hidden catalysts for tumor progression, particularly through enhancing cell migration and possibly fueling metastasis - a finding that sheds light on a significant and previously underexplored area of concern.

Antiproliferative and Antitelomerase Effects of Silymarin on Human Colorectal and Hepatocellular Carcinoma Cells.

Silymarin, a widely-used hepatoprotective agent, has shown antitumor properties in both in vitro and animal studies. Currently, there is limited knowledge regarding silymarin's antitelomerase effects on human colorectal cancer and hepatocyte carcinoma cells. In this study, we investigated the antiproliferative and antitelomerase effects of silymarin on four human colorectal cancer and HepG2 hepatocyte carcinoma cell lines. The cell viability and telomerase activity were assessed using MTT and the telomerase repeat amplification protocol assay, respectively. We also investigated the effects of silymarin on the expression of human telomerase reverse transcriptase and its promoter methylation in HepG2 cells by real-time RT-PCR and methylation-specific PCR, respectively. Silymarin treatment inhibited cell proliferation and telomerase activity in all cancer cells. After 24 h of treatment, silymarin exhibited IC50 values ranging from 19 - 56.3 µg/mL against these cancer cells. A 30-min treatment with silymarin at the IC50 concentration effectively inhibited telomerase activity in cell-free extracts of both colorectal cancer and hepatocyte carcinoma cells. Treatment of HepG2 cells with 10 and 30 µg/mL of silymarin for 48 h resulted in a decrease in human telomerase reverse transcriptase expression to 75 and 35% of the level observed in the untreated control (p < 0.01), respectively. Treatment with silymarin (10, 30, and 60 µg/mL) for 48 h did not affect human telomerase reverse transcriptase promoter methylation in HepG2 cells. In conclusion, our findings suggest that silymarin inhibits cancer cell growth by directly inhibiting telomerase activity and downregulating its human telomerase reverse transcriptase catalytic subunit. However, silymarin did not affect human telomerase reverse transcriptase promoter methylation at the concentrations of 10 - 60 µg/mL used in this study.

TiO2-Ti3C2 Nanocomposites Utilize Their Photothermal Activity for Targeted Treatment of Colorectal Cancer.

The search for effective and low-risk treatment methods for colorectal cancer (CRC) is a pressing concern, given the inherent risks and adverse reactions associated with traditional therapies. Photothermal therapy (PTT) has emerged as a promising approach for cancer treatment, offering advantages such as non-radiation, non-invasiveness, and targeted treatment. Consequently, the development of nanoparticles with high stability, biocompatibility, and photothermal effects has become a significant research focus within the field of PTT. In this study, TiO2-Ti3C2 nanocomposites were synthesized and characterized, and their photothermal conversion efficiency in the near-infrared region II (NIR-II) was determined. Then studied the in vivo and in vitro photothermal activity and anti-tumor effect of TiO2-Ti3C2 in human colorectal cancer cell lines and nude mice subcutaneous tumor model. The results showed that TiO2-Ti3C2 nanocomposites have strong absorption ability in the NIR-II, and have high photothermal conversion efficiency under 1064 nm (0.5 W/cm2, 6 min) laser stimulation. In addition, in vitro experiments showed that TiO2-Ti3C2 nanocomposites significantly inhibited the invasion, migration, and proliferation of colorectal cancer cells, and induced cell apoptosis; in vivo, experiments showed that TiO2-Ti3C2 nanocomposites-mediated PTT had good biocompatibility and efficient targeted inhibition of tumor growth. In conclusion, TiO2-Ti3C2 nanocomposites can be used as NIR-II absorption materials in PTT to suppress the invasion, migration, and proliferation of colorectal cancer cells, induce colorectal cancer cell apoptosis, and thus inhibit the development of CRC. Therefore, TiO2-Ti3C2 nanocomposites can be used as potential anti-tumor drugs for photothermal ablation of colorectal cancer cells.

Effect of Paxillin Expression and Phosphorylation on Colorectal Cancer Prognosis and Metastasis.

Colorectal cancer (CRC) is the third most common cancer worldwide, and metastasis is strongly associated with poor prognosis in patients with CRC. We have previously found that the expression and phosphorylation of paxillin (PXN) play an important role in the metastatic potential of breast cancer. This study examined the potential role of PXN in CRC metastasis. Resected tumor specimens from 92 patients with CRC were subjected to immunohistochemical analysis of PXN levels. Three human CRC cell lines, HCT116, LoVo, and SW480 were used for scratch and transwell invasion assays to examine the effects of PXN over-expression. RNA sequencing was performed to obtain the expression profiles under PXN over-expression. High levels of PXN were significantly correlated with advanced stage, higher carcinoembryonic antigen and carbohydrate antigen 19-9 levels, and poorer overall survival. The migration ability of CRC cells was enhanced by exogenous PXN over-expression, but this enhancement was not observed in cells harboring exogenously mutated PXN at Tyr31 or Tyr88 phosphorylation sites. In PXN-over-expressing cells, TNF-α signaling via NF-[Formula: see text]B was positively enriched. PXN expression and phosphorylation at Tyr31 or Tyr88 may influence the migration and invasion of CRC cells. PXN expression and phosphorylation at Tyr31 or Tyr88 are promising targets for evaluating prognosis and treating CRC.

Ruthenium-dihydroartemisinin complex: a promising new compound for colon cancer prevention via G1 cell cycle arrest, apoptotic induction, and adaptive immune regulation.

Artemisinin (ART) and its derivatives are important antimalaria agents and have received increased attention due to their broad biomedical effects, such as anticancer and anti-inflammation activities. Recently, ruthenium-derived complexes have attracted considerable attention as their anticancer potentials were observed in preclinical and clinical studies. To explore an innovative approach in colorectal cancer (CRC) management, we synthesized ruthenium-dihydroartemisinin complex (D-Ru), a novel metal-based artemisinin derivative molecule, and investigated its anticancer, anti-inflammation, and adaptive immune regulatory properties. Compared with its parent compound, ART, D-Ru showed stronger antiproliferative effects on the human CRC cell lines HCT-116 and HT-29. The cancer cell inhibition of D-Ru comprised G1 cell cycle arrest via the downregulation of cyclin A and the induction of apoptosis. ART and D-Ru downregulated the expressions of pro-inflammatory cytokines IL-1β, IL-6, and IL-8. Although ART and D-Ru did not suppress Treg cell differentiation, they significantly inhibited Th1 and Th17 cell differentiation. Our results demonstrated that D-Ru, a novel ruthenium complexation of ART, remarkably enhanced its parent compound's anticancer action, while the anti-inflammatory potential was not compromised. The molecular mechanisms of action of D-Ru include inhibition of cancer cell growth via cell cycle arrest, induction of apoptosis, and anti-inflammation via regulation of adaptive immunity.