Resistant Cancer Stem Cells Research Articles

DLK1 Is Associated with Stemness Phenotype in Medullary Thyroid Carcinoma Cell Lines.

Medullary thyroid carcinoma (MTC) is a rare and aggressive tumor, often requiring systemic treatment in advanced or metastatic stages, where drug resistance presents a significant challenge. Given the role of cancer stem cells (CSCs) in cancer recurrence and drug resistance, we aimed to identify CSC subpopulations within two MTC cell lines harboring pathogenic variants in the two most common MEN2-associated codons. We analyzed 15 stemness-associated markers, along with well-established thyroid stem cell markers (CD133, CD44, and ALDH1), a novel candidate (DLK1), and multidrug resistance proteins (MRP1 and MRP3). The ability to efflux the fluorescent dye Hoechst 3342 and form spheroids, representing CSC behavior, was also assessed. MZ-CRC-1 cells (p.M918T) displayed higher expressions of canonical markers, DLK1, and MRP proteins than TT cells (p.C634W). MZ-CRC-1 cells also formed more spheroids and showed less dye accumulation (p < 0.0001). Finally, we observed that DLK1+ cells (those expressing DLK1) in both cell lines exhibited significantly higher levels of stemness markers compared to DLK1- cells (those lacking DLK1 expression). These findings underscore DLK1's role in enhancing the stemness phenotype, providing valuable insights into MTC progression and resistance and suggesting potential therapeutic implications.

Targeting Lipid Metabolism in Cancer Stem Cells for Anticancer Treatment.

Cancer stem cells (CSCs), or tumor-initiating cells (TICs), are small subpopulations (0.0001-0.1%) of cancer cells that are crucial for cancer relapse and therapy resistance. The elimination of each CSC is essential for achieving long-term remission. Metabolic reprogramming, particularly lipids, has a significant impact on drug efficacy by influencing drug diffusion, altering membrane permeability, modifying mitochondrial function, and adjusting the lipid composition within CSCs. These changes contribute to the development of chemoresistance in various cancers. The intricate relationship between lipid metabolism and drug resistance in CSCs is an emerging area of research, as different lipid species play essential roles in multiple stages of autophagy. However, the link between autophagy and lipid metabolism in the context of CSC regulation remains unclear. Understanding the interplay between autophagy and lipid reprogramming in CSCs could lead to the development of new approaches for enhancing therapies and reducing tumorigenicity in these cells. In this review, we explore the latest findings on lipid metabolism in CSCs, including the role of key regulatory enzymes, inhibitors, and the contribution of autophagy in maintaining lipid homeostasis. These recent findings may provide critical insights for identifying novel pharmacological targets for effective anticancer treatment.

RNA lipid nanoparticles as efficient in vivo CRISPR-Cas9 gene editing tool for therapeutic target validation in glioblastoma cancer stem cells

In vitro and ex-vivo target identification strategies often fail to predict in vivo efficacy, particularly for glioblastoma (GBM), a highly heterogenous tumor rich in resistant cancer stem cells (GSCs). An in vivo screening tool can improve prediction of therapeutic efficacy by considering the complex tumor microenvironment and the dynamic plasticity of GSCs driving therapy resistance and recurrence. This study proposes lipid nanoparticles (LNPs) as an efficient in vivo CRISPR-Cas9 gene editing tool for target validation in mesenchymal GSCs. LNPs co-delivering mRNA (mCas9) and single-guide RNA (sgRNA) were successfully formulated and optimized facilitating both in vitro and in vivo gene editing. In vitro, LNPs achieved up to 67 % reduction in green fluorescent protein (GFP) expression, used as a model target, outperforming a commercial transfection reagent. Intratumoral administration of LNPs in GSCs resulted in ∼80 % GFP gene knock-out and a 2-fold reduction in GFP signal by day 14. This study showcases the applicability of CRISPR-Cas9 LNPs as a potential in vivo screening tool in GSCs, currently lacking effective treatment. By replacing GFP with a pool of potential targets, the proposed platform presents an exciting prospect for therapeutic target validation in orthotopic GSCs, bridging the gap between preclinical and clinical research.

Ribosome biogenesis and ribosomal proteins in cancer stem cells: a new therapeutic prospect.

Ribosome has been considered as the fundamental macromolecular machine involved in protein synthesis in both prokaryotic and eukaryotic cells. This protein synthesis machinery consists of several rRNAs and numerous proteins. All of these factors are synthesized, translocated and assembled in a tightly regulated process known as ribosome biogenesis. Any impairment in this process causes development of several diseases like cancer. According to growing evidences, cancer cells display alteration of several ribosomal proteins. Besides, most of them are considered as key molecules involved in ribosome biogenesis, suggesting a correlation between those proteins and formation of ribosomes. Albeit, defective ribosome biogenesis in several cancers has gained prime importance, regulation of this process in cancer stem cells (CSCs) are still unrecognized. In this article, we aim to summarize the alteration of ribosome biogenesis and ribosomal proteins in CSCs. Moreover, we want to highlight the relation of ribosome biogenesis with hypoxia and drug resistance in CSCs based on the existing evidences. Lastly, this review wants to pay attention about the promising anti-cancer drugs which have potential to inhibit ribosome biogenesis in cancer cells as well as CSCs.

Rational Design of a Multi-epitope Vaccine Using Neoantigen Against Colorectal Cancer Through Structural Immunoinformatics and ML-Enabled Simulation Approach.

Colorectal cancer poses a substantial global health burden. Regarding WHO, the global burden of colorectal cancer will be about 3.2 million new cases by the year 2040. Simultaneously, it indicated that this cancer will cause 6 million deaths per year. Despite advancements in chemotherapy and monoclonal antibody therapy, the disease remains a significant challenge due to the resistance of cancer stem cells. This study endeavors to design a multi-epitopic peptide (9-mer epitopes) neoantigen-based vaccine targeting the TLR4/MD2 complex as a potential vaccine candidate. These tumor-specific neoantigens (TSA) are considered novel antigens that can be used for vaccine development against cancer. To develop the neoantigen vaccine candidate, we used the SPENCER database, and 140 lncRNA-derived epitopes were retrieved. From 140 epitopes, we selected seven neoantigens with high antigenic properties for the vaccine construct. A novel vaccine containing epitopes, linkers(EAAAK and CPCPG), and adjuvants(ribosomal [50S]protein L7L12) was formulated utilizing immunoinformatics tools. The vaccine's biophysical properties were evaluated, revealing its antigenicity(0.6469), stability(instability index:37.05), and potential for immune system interaction. In-depth structural analyses, molecular docking studies, and ML-enabled immune simulation profiling underscored the vaccine's structural integrity, binding affinity with TLR4, and ability to elicit robust immune responses against colorectal cancer antigens. These findings suggest that the multi-epitopic vaccine holds promise as a next-generation approach to combat colorectal cancer. Our in silico studies exhibit potentiality of the vaccine candidate; however, further in vivo and in vitro investigations are crucial to validate immunogenicity, safety, and efficacy before clinical implementation. Our study developed a first-time lncRNA-derived neoantigen-based cancer vaccine.

A Green Synthesis of Au-Ag Alloy Nanoparticles using Polydopamine Chemistry: Evaluation of their Anticancer Potency Towards Both MCF-7 Cells and their Cancer Stem Cells Subgroup.

Limited chemotherapy efficacy and cancer stem cells (CSCs)-induced therapeutic resistance are major difficulties for tumour treatment. Adopting more efficient therapies to eliminate bulk-sensitive cancer cells and resistant CSCs is urgently needed. Based on the potential and functional complementarity of gold and silver nanoparticles (AuNPs or AgNPs) on tumour treatment, bimetallic NPs (alloy) have been synthesized to obtain improved or even newly emerging bioactivity from a combination effect. This study reported a facile, green and economical preparation of Au-Ag alloy NPs using biocompatible polydopamine (PDA) as a reductant, capping, stabilizing and hydrophilic agent. These alloy NPs were quasi-spherical with rough surfaces and recorded in diameters of 80 nm. In addition, these alloy NPs showed good water dispersity, stability and photothermal effect. Compared with monometallic counterparts, these alloy NPs demonstrated a dramatically enhanced cytotoxic/pro-apoptotic/necrotic effect towards bulk-sensitive MCF-7 and MDA-MB-231 cells. The underlying mechanism regarding the apoptotic action was associated with a mitochondria-mediated pathway, as evidenced by Au3+/Ag+ mediated Mitochondria damage, ROS generation, DNA fragmentation and upregulation of certain apoptotic-related genes (Bax, P53 and Caspase 3). Attractively, these Au-Ag alloy NPs showed a remarkably improved inhibitory effect on the mammosphere formation capacity of MCF-7 CSCs. All the positive results were attributed to incorporated properties from Au, Ag and PDA, the combination effect of chemotherapy and photothermal therapy and the nano-scaled structure of Au-Ag alloy NPs. In addition, the high biocompatibility of Au-Ag alloy NPs supported them as a good candidate in cancer therapy.

Novel Anti-Cancer Stem Cell Compounds: A Comprehensive Review.

Cancer stem cells (CSCs) possess a significant ability to renew themselves, which gives them a strong capacity to form tumors and expand to encompass additional body areas. In addition, they possess inherent resistance to chemotherapy and radiation therapies used to treat many forms of cancer. Scientists have focused on investigating the signaling pathways that are highly linked to the ability of CSCs to renew themselves and maintain their stem cell properties. The pathways encompassed are Notch, Wnt/β-catenin, hedgehog, STAT3, NF-κB, PI-3K/Akt/mTOR, sirtuin, ALDH, MDM2, and ROS. Recent studies indicate that directing efforts towards CSC cells is essential in eradicating the overall cancer cell population and reducing the likelihood of tumor metastasis. As our comprehension of the mechanisms that stimulate CSC activity, growth, and resistance to chemotherapy advances, the discovery of therapeutic drugs specifically targeting CSCs, such as small-molecule compounds, holds the potential to revolutionize cancer therapy. This review article examines and analyzes the novel anti-CSC compounds that have demonstrated effective and selective targeting of pathways associated with the renewal and stemness of CSCs. We also discussed their special drug metabolism and absorption mechanisms. CSCs have been the subject of much study in cancer biology. As a possible treatment for malignancies, small-molecule drugs that target CSCs are gaining more and more attention. This article provides a comprehensive review of the current state of key small-molecule compounds, summarizes their recent developments, and anticipates the future discovery of even more potent and targeted compounds, opening up new avenues for cancer treatment.

Biomimetic liposome amplifying mitochondrial damage to potential cancer radio-immunotherapy

Radiotherapy, despite its precision and non-invasiveness, often fails due to the resistance of cancer stem cells (CSCs), which are characterized by high self-renewal capabilities and superior DNA repair mechanisms. These cells can evade RT and lead to tumor recurrence and metastasis. To address this challenge, a novel delivery system named PB has been introduced. This system combines liposomes with platelet membranes to encapsulate Bis-2-(5-phenylacetamido-1,2,4-thiadiazol-2-yl) ethyl sulfide (BPTES), thus enhancing its delivery and release specifically at tumor sites. In addition, this system not only targets CSCs effectively but also increases the local concentration of BPTES upon X-ray irradiation, which reduces glutathione levels in tumor cells, thereby increasing oxidative stress and damaging mitochondria. PB-elicited mitochondrial damage as the STING signal initiator, which mediated significant upregulation in the expression of a cGAS-STING pathway-related protein thereby amplifying the STING signal. Systemic intravenous administration of PB remarkably promoted DC maturation and CD8+ T cell infiltration, thus eliciting strong antitumor effects. Overall, this PB system presents a potent method to overcome CSC-related resistance and offers a promising approach for future cancer treatment protocols.

Dysregulated Wnt/β-catenin signaling confers resistance to cuproptosis in cancer cells.

Cuproptosis is characterized by the aggregation of lipoylated enzymes of the tricarboxylic acid cycle and subsequent loss of iron-sulfur cluster proteins as a unique copper-dependent form of regulated cell death. As dysregulation of copper homeostasis can induce cuproptosis, there is emerging interest in exploiting cuproptosis for cancer therapy. However, the molecular drivers of cancer cell evasion of cuproptosis were previously undefined. Here, we found that cuproptosis activates the Wnt/β-catenin pathway. Mechanistically, copper binds PDK1 and promotes its interaction with AKT, resulting in activation of the Wnt/β-catenin pathway and cancer stem cell (CSC) properties. Notably, aberrant activation of Wnt/β-catenin signaling conferred resistance of CSCs to cuproptosis. Further studies showed the β-catenin/TCF4 transcriptional complex directly binds the ATP7B promoter, inducing its expression. ATP7B effluxes copper ions, reducing intracellular copper and inhibiting cuproptosis. Knockdown of TCF4 or pharmacological Wnt/β-catenin blockade increased the sensitivity of CSCs to elesclomol-Cu-induced cuproptosis. These findings reveal a link between copper homeostasis regulated by the Wnt/β-catenin pathway and cuproptosis sensitivity, and suggest a precision medicine strategy for cancer treatment through selective cuproptosis induction.

PCK1-mediated glycogenolysis facilitates ROS clearance and chemotherapy resistance in cervical cancer stem cells

Cervical cancer, one of the most common gynecological cancers, is primarily caused by human papillomavirus (HPV) infection. The development of resistance to chemotherapy is a significant hurdle in treatment. In this study, we investigated the mechanisms underlying chemoresistance in cervical cancer by focusing on the roles of glycogen metabolism and the pentose phosphate pathway (PPP). We employed the cervical cancer cell lines HCC94 and CaSki by manipulating the expression of key enzymes PCK1, PYGL, and GYS1, which are involved in glycogen metabolism, through siRNA transfection. Our analysis included measuring glycogen levels, intermediates of PPP, NADPH/NADP+ ratio, and the ability of cells to clear reactive oxygen species (ROS) using biochemical assays and liquid chromatography–mass spectrometry (LC–MS). Furthermore, we assessed chemoresistance by evaluating cell viability and tumor growth in NSG mice. Our findings revealed that in drug-resistant tumor stem cells, the enzyme PCK1 enhances the phosphorylation of PYGL, leading to increased glycogen breakdown. This process shifts glucose metabolism towards PPP, generating NADPH. This, in turn, facilitates ROS clearance, promotes cell survival, and contributes to the development of chemoresistance. These insights suggest that targeting aberrant glycogen metabolism or PPP could be a promising strategy for overcoming chemoresistance in cervical cancer. Understanding these molecular mechanisms opens new avenues for the development of more effective treatments for this challenging malignancy.

Targeting resistant breast cancer stem cells in a three-dimensional culture model with oleuropein encapsulated in methacrylated alginate microparticles

BackgroundCancer stem cells (CSCs) are a subpopulation of cancer cells that are believed to be responsible for tumor initiation, progression, metastasis, and resistance to conventional therapies. Oleuropein as a natural compound found in olive leaves and olive oil, has potential therapeutic effects in cancer treatment, particularly in targeting CSCs. It induces apoptosis in CSCs while sparing normal cells, inhibit proliferation, migration, and invasion, and suppress the self-renewal ability of CSCs. Additionally, oleuropein has shown synergistic effects with conventional chemotherapy drugs, enhancing their efficacy against CSCs.ObjectivesThis study aims to selectively target therapeutically resistant cancer stem cells (CSCs) within a heterogeneous tumor population by utilizing oleuropein (OLE) encapsulated in methacrylated alginate (OLE-mALG) within an in vivo-like microenvironment.PurposeThis study aims to target therapeutically resistant cancer stem cells (CSCs) with oleuropein (OLE) encapsulated in the methacrylated alginate (OLE-mALG) in a heterogeneous tumor population with an in vivo-like microenvironment.MethodsCo-culture of CSCs with non-tumorogenic MCF-12 A cells was performed, the 3D breast cancer model was supported with methocel/matrigel/collagen-I, and vascularization was ensured with human umbilical vein endothelial cells (HUVEC). Then, OLE-loaded methacrylated alginate microparticles (mALG) were formed by dual crosslinking in the presence of both ionic and visible light obtained with a droplet based microfluidic system. The characterization and effectiveness of the produced OLE-mALG were evaluated by the FTIR, swelling/degradation/release analysis. Before producing OLE loaded mALG microparticles, a preliminary study was carried out to determine the effective dose of OLE for cells and the duration of OLE action on MCF-7, CSCs and MCF-12 A. Subsequently, CSC viability (WST-1), apoptosis (Bcl-2, Bax, caspase-3, caspase-9), stemness (OCT3/4, NANOG, SOX2), EMT profile (E-cadherin, Vimentin, Slug) and proliferation (SURVIVIN, p21, CYCLIN D1) after OLE-mALG treatment were all evaluated in the 3D model.ResultsOLE was encapsulated in mALG with an efficiency of 90.49% and released 73% within 7 h. OLE-mALG induced apoptosis through the decrease in anti-apoptotic Bcl-2 and an increase in pro-apoptotic Bax, caspase-3, and caspase-9 protein levels. While Vimentin and Slug protein levels decreased after 200 µg/mL OLE-mALG treatment to 3D breast cancer culture, E-cadherin levels increased. OLE-mALG treatment to CSC co-culture led to a decrease in proliferation by triggering p21/SURVIVIN expressions, and also resulted in an increase in stemness genes (OCT3/4/NANOG/SOX2).Conclusion200 µg/mL OLE-loaded mALG microparticles suppressed epithelial-to-mesenchymal transition by suppressing Vimentin and Slug protein levels, and increased E-cadherin levels in the 3D breast cancer model we created with CSCs, MCF-12 A and HUVECs. This complex system may allow the use of personalized cells for rapid drug screening in preclinical studies compared to animal experiments. OLE-mALG showed apoptotic and metastasis suppressive properties in cancer cells and it was concluded that it can be used in combination with or alternatively with chemotherapeutic agents to target breast cancer stem cells.Graphical abstract

Cancer Stem Cell Metastatic Checkpoints and Glycosylation Patterns: Implications for Therapeutic Strategies

Cancer stem cells (CSCs), found within tumors, are powerful drivers of disease recurrence and metastasis. Their abilities to self-renew and maintain stem-like properties make treatment difficult, as their heterogeneity and metastatic properties can lead to resistance and limit the effectiveness of standard therapies. Given their significance, CSCs are typically isolated based on combinations of markers, which often indicate heterogeneous populations of CSCs. The lack of consensus in cell characterization poses challenges in defining and targeting these cells for effective therapeutic interventions. In this review, we suggest five promising molecules—ABCB5, CD26, CD66c, uPAR, and Trop-2—chosen specifically for their distinct distribution within cancer types and clinical relevance. These markers, expressed at the cell surface of CSCs, could significantly enhance the specificity of cancer stemness characterization. This review focuses on describing their pivotal roles as biomarker checkpoints for metastasis. Additionally, this review outlines existing literature on glycosylation modifications, which present intriguing epitopes aimed at modulating the stability and function of these markers. Finally, we summarize several promising in vivo and clinical trial approaches targeting the mentioned surface markers, offering potential solutions to overcome the therapeutic resistance of CSCs and addressing current gaps in treatment strategies.

The effect of turmeric extract (Curcuma longa) on IL-6 expression

Background: Breast cancer in Indonesia is reported to have reached 68,858 out of 396,914 new cases of cancer, with an incidence rate of 16.6% based on Globocan 2020 data. Complementary therapies are much sought after for psychological and economic reasons and have minimal side effects. Curcumin has anti-carcinogenic properties. IL-6 plays an important role in the growth and metastasis of breast cancer cells, renewal of breast cancer stem cells, and drug resistance in breast cancer stem cells. Methods: A randomized controlled trial with post-test only group design using artificial female Balb/c strain rats (Mus Musculus) with DMBA-induced mammary adenocarcinoma nodules were reported, rats were divided into four groups randomly, namely, Control (K), Treatment 1: turmeric extract dose 100mg/KgBW (P1), Treatment 2: turmeric extract dose 150mg/KgBW (P2), Treatment 3: turmeric extract dose 200mg/KgBW (P3). Variables under study were IL-6 expression. One Way Anova test, followed by the Post-hoc Test, was used to test the difference among and between groups. Results: The mean value of IL-6 expression in groups K (53,59 ± 8,37), P1 (50,66 ± 9,59), P2 (66,93 ± 9,64), P3 (64,58 ± 5,97). The Post-Hoc test showed significant differences in IL-6 expression from group K against P2 (p=0.038), group P1 against P2 (p=0.015), and P3 (p=0.040). Conclusion: Turmeric extract (Curcuma longa) had an effect on IL-6 expression in the control group and the treatment group.

Abstract 489: Unlocking immune resistance and metastasis of PDAC via dual acting circularized nanodisc

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and deadliest forms of cancer. While major progress in immunotherapy has been made in recent years, it remains poorly effective in this malignancy. Two key players stand behind immune resistance of PDAC and inadequate efficacy of immunotherapy to suppress its metastasis. First, the immune-resistant pancreatic cancer stem cells (CSCs) evade immune surveillance acting as a source for tumor relapse and metastasis. This immune resistance stems from low immunogenicity of PDAC cells as well as the inaccessible CSCs that reside deep in the tumor core. Second, pancreatic cancer associated fibroblasts (CAFs) fuel metastasis of PDAC cells by suppressing their immune recognition and establishing pre-metastatic niche at distant organs to help their colonization. Our hypothesis is to overcome immune resistance of PDAC and inhibit early steps of its metastasis via simultaneous immunogenic eradication of immune resistant CSCs and switching immunosuppressive and pro-metastatic CAFs into quiescent ones. Therefore, we engineered ultrasmall circularized nanodiscs (cND) that encapsulate oncolytic peptide LTX-315 and fibroblast remodeling Notch signaling inhibitor. The engineered oncolytic LTX-315 loaded cND successfully induced immunogenic cell death (ICD) of both bulk PANC1 and pancreatic CSCs. Compared to non-treated and free LTX-315 treated cells, LTX-315 cND resulted in enhanced release of DAMPs including ATP and HMGB-1 as well as surface translocation of calreticulin. The ultrasmall size (9 nm) of cND enabled its deep tumor penetration to eradicate resistant CSCs, as revealed using 3D PDAC heterospheroids. In parallel, the Notch blocking cND promoted quiescence of the activated pancreatic stellate cells as denoted by downregulation of SMA, FAP and collagen. In KPC syngeneic PDAC mouse model, the dual oncolytic/Notch blocking cND combined with aPD-L1 therapy significantly suppressed tumor growth and prevented its metastasis to liver compared to vehicle-treated mice. Immunophenotyping study showed marked reduction in the abundance of CSCs and CAFs in the tumor treated with the cNDs. Moreover, the tumor infiltration of CD86+ MHCII+ dendritic cells and cytotoxic CD8+ T cells was enhanced after treatment with the cND. Overall, our dual strategy of targeting pancreatic CSCs and CAFs via oncolytic/Notch blocking cND boosted the anti-tumor and anti-metastatic efficacy of aPD-L1 therapy to eliminate primary PDAC tumor and suppress its metastasis. Citation Format: Ahmed Elzoghby, Hagar Emam, Seungbin Yim, Cuiyan Xin, Mahmoud Nasr. Unlocking immune resistance and metastasis of PDAC via dual acting circularized nanodisc [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 489.

Abstract 574: Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation

Abstract Nonalcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma (HCC) is an emerging malignancy in the developed countries. However, the mechanisms contributing to its formation remain largely unknown. Given the role of cancer stem cells (CSCs) in tumor initiation and therapeutic resistance, we hypothesize that adipocytes, one of the key cellular factors within the tumor microenvironment of NAFLD-induced HCC, may play a critical role in HCC development and drug resistance by regulating liver CSCs. Using a co-culture system in which differentiated adipocytes were grown with HCC cells, we found that adipocytes enhanced the self-renewal ability of HCC cells through indirect paracrine secretion. HCC cells pre-incubated with conditioned medium from adipocytes showed enhanced liver CSC properties including self-renewal, tumorgenicity, invasiveness and chemo-resistance to doxorubicin and sorafenib. Secretome profiles showed that FABP4 was preferentially secreted by adipocytes and its level was further augmented when co-cultured with HCC cells. Concurrently, recombinant FABP4 enhanced CSC properties of HCC cells. Drastic delay in the onset of tumor development in FABP4−/- mice upon DEN-injected and high fat diet-induced mouse models of NAFLD-HCC. Mass spectrometry analysis revealed ITGB1 as a direct binding partner of FABP4 for the first time. This data, together with the observation of significant downregulation of the Wnt/β-catenin pathway in tumors of FABP4−/− mice, revealed the role of adipocyte-derived FABP4 promotes liver CSC function by activating the PI3K/Akt/β-catenin signaling pathway via ITGB1. Overexpression of ITGB1 led to poorer survival of HCC patients with NAFLD as a risk factor. The development of a monoclonal neutralizing antibody against FABP4 successfully blocked FABP4-driven CSC functions, implicating the targetability of FABP4 for the treatment of NAFLD-induced HCC. Citation Format: Carmen Oi Ning Leung, Shilpa Gurung, Katherine Po Sin Chung, Sze Man Chan, Terence Kin Wah Lee. Adipocyte-derived FABP4 promotes non-alcoholic fatty liver disease (NAFLD)-induced hepatocellular carcinoma by driving ITGB1-mediated β-catenin activation [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 574.

Inhibition of the AURKA/YAP1 axis is a promising therapeutic option for overcoming cetuximab resistance in colorectal cancer stem cells

BackgroundPrimary resistance to anti-EGFR therapies affects 40% of metastatic colorectal cancer patients harbouring wild-type RAS/RAF. YAP1 activation is associated with this resistance, prompting an investigation into AURKA’s role in mediating YAP1 phosphorylation at Ser397, as observed in breast cancer.MethodsWe used transcriptomic analysis along with in vitro and in vivo models of RAS/RAF wild-type CRC to study YAP1 Ser397 phosphorylation as a potential biomarker for cetuximab resistance. We assessed cetuximab efficacy using CCK8 proliferation assays and cell cycle analysis. Additionally, we examined the effects of AURKA inhibition with alisertib and created a dominant-negative YAP1 Ser397 mutant to assess its impact on cancer stem cell features.ResultsThe RAS/RAF wild-type CRC models exhibiting primary resistance to cetuximab prominently displayed elevated YAP1 phosphorylation at Ser397 primarily mediated by AURKA. AURKA-induced YAP1 phosphorylation was identified as a key trigger for cancer stem cell reprogramming. Consequently, we found that AURKA inhibition had the capacity to effectively restore cetuximab sensitivity and concurrently suppress the cancer stem cell phenotype.ConclusionsAURKA inhibition holds promise as a therapeutic approach to overcome cetuximab resistance in RAS/RAF wild-type colorectal cancer, offering a potential means to counter the development of cancer stem cell phenotypes associated with cetuximab resistance.

SOX2 and OCT4 mediate radiation and drug resistance in pancreatic tumor organoids

Pancreatic cancer has a five-year survival rate of only 10%, mostly due to late diagnosis and limited treatment options. In patients with unresectable disease, either FOLFIRINOX, a combination of 5-fluorouracil (5-FU), oxaliplatin and irinotecan, or gemcitabine plus nab-paclitaxel combined with radiation are frontline standard regimens. However, chemo-radiation therapy has shown limited success because patients develop resistance to chemotherapy and/or radiation. In this study, we evaluated the role of pancreatic cancer stem cells (CSC) using OCT4 and SOX2, CSC markers in mouse pancreatic tumor organoids. We treated pancreatic tumor organoids with 4 or 8 Gy of radiation, 10 μM of 5-FU (5-Fluorouracil), and 100 μM 3-Bromopyruvate (3BP), a promising anti-cancer drug, as a single treatment modalities, and in combination with RT. Our results showed significant upregulation of, OCT4, and SOX2 expression in pancreatic tumor organoids treated with 4 and 8 Gy of radiation, and downregulation following 5-FU treatment. The expression of CSC markers with increasing treatment dose exhibited elevated upregulation levels to radiation and downregulation to 5-FU chemotherapy drug. Conversely, when tumor organoids were treated with a combination of 5-FU and radiation, there was a significant inhibition in SOX2 and OCT4 expression, indicating CSC self-renewal inhibition. Noticeably, we also observed that human pancreatic tumor tissues exhibited heterogeneous and aberrant OCT4 and SOX2 expression as compared to normal pancreas, indicating their potential role in pancreatic cancer growth and therapy resistance. In addition, the combination of 5-FU and radiation treatment exhibited significant inhibition of the β-catenin pathway in pancreatic tumor organoids, resulting in sensitization to treatment and organoid death. In conclusion, our study emphasizes the crucial role of CSCs in therapeutic resistance in PC treatment. We recommend using tumor organoids as a model system to explore the impact of CSCs in PC and identify new therapeutic targets.

Anti-Tumor Efficacy of Oleuropein-Loaded ZnO/Au Mesoporous Silica Nanoparticle in 5-FU-Resistant Colorectal Cancer Cells.

5-fluorouracil (5-FU) is a first-line chemotherapeutic agent used to treat colorectal cancer (CRC). However, 5-FU induces drug resistance and activation of cancer stem cells (CSCs). In the present study, we designed a novel biocompatible nanomedicine system with high efficacy and biocompatibility by synthesizing mesoporous silica nanoparticle (MSN)-structured ZnO and gold ions. Oleuropein (OLP) is a phenolic compound derived from olive leaves that exerts anti-cancer effects. Therefore, we synthesized OLP-loaded ZnO/Au MSNs (ZnO/Au/OLP MSNs) and examined their anti-cancer effects on 5-FU-resistant CRC cells. ZnO/Au MSNs were synthesized and functionalized, and their physical and chemical compositions were characterized using UV-visible spectroscopy, dynamic light scattering, and transmission electron microscopy (TEM). Their effects were assessed in terms of cellular proliferation capacity, migration and invasion ability, colony-forming ability, spheroid-forming ability, reactive oxygen species (ROS) production, and mitochondrial membrane depolarization. ZnO/Au MSNs were mostly composed of various ions containing ZnO and gold ions, had a spheroid phenotype, and exhibited no cytotoxicity. ZnO/Au/OLP MSNs reduced cell viability and CSC formation and induced apoptosis of 5-FU-resistant CRC cells via necrosis via ROS accumulation and DNA fragmentation. ZnO/Au/OLP MSNs exhibited anti-cancer activity by upregulating necrosis. These results revealed that ZnO/Au/OLP MSNs are a novel drug delivery system for 5-FU CRC therapy.

BBT-877, a Novel Autotaxin Inhibitor, Abrogates Drug Resistance in Epithelial Ovarian Cancer Stem Cells.

Cancer stem cells (CSCs) contribute significantly to the poor prognosis of patients with epithelial ovarian cancer (EOC) due to their roles in drug resistance and tumor metastasis. Autotaxin (ATX) plays a pivotal role in the maintenance of the CSC-like properties of EOC tumors. BBT-877 is a novel ATX inhibitor used in clinical treatment of idiopathic pulmonary fibrosis. However, the effects of BBT-877 on drug resistance and metastasis in ovarian CSCs remain unknown. In this study, we aimed to investigate the effects of BBT-877 on drug resistance and intraperitoneal metastasis of EOC. Spheroid-forming CSCs, which were isolated from two EOC cell lines, A2780 and SKOV3, were investigated by cell viability, western blot, PCR, Spheroid-forming assay, and in vivo experiments. Spheroid-forming CSCs exhibited increased CSC-like properties and paclitaxel (PTX) resistance. BBT-877 treatment inhibited the viability of spheroid-forming CSCs more potently than that of adherent ovarian cancer cell lines. Combinatorial treatment with BBT-877 and PTX significantly attenuated the viability of spheroid-forming CSCs. In a SKOV3 cells-derived intraperitoneal metastasis model, BBT-877 treatment reduced the number of metastatic tumor nodes, while combinatorial treatment with BBT-877 and PTX more potently attenuated the formation of metastatic nodes and accumulation of ascitic fluid. These results suggest that BBT-877 can be combined with conventional anticancer drugs for the treatment of patients with recurrent or drug-resistant EOC.

IGF-1-mediated FOXC1 overexpression induces stem-like properties through upregulating CBX7 and IGF-1R in esophageal squamous cell carcinoma.

Substantial evidence attests to the pivotal role of cancer stem cells (CSC) in both tumorigenesis and drug resistance. A member of the forkhead box (FOX) family, FOXC1, assumes significance in embryonic development and organogenesis. Furthermore, FOXC1 functions as an overexpressed transcription factor in various tumors, fostering proliferation, enhancing migratory capabilities, and promoting drug resistance, while maintaining stem-cell-like properties. Despite these implications, scant attention has been devoted to its role in esophageal squamous cell carcinoma. Our investigation revealed a pronounced upregulation of FOXC1 expression in ESCC, correlating with a poor prognosis. The downregulation of FOXC1 demonstrated inhibitory effects on ESCC tumorigenesis, proliferation, and tolerance to chemotherapeutic agents, concurrently reducing the levels of stemness-related markers CD133 and CD44. Further studies validated that FOXC1 induces ESCC stemness by transactivating CBX7 and IGF-1R. Additionally, IGF-1 activated the PI3K/AKT/NF-κB and MEK/ERK/NF-κB pathways through its binding to IGF-1R, thereby augmenting FOXC1 expression. Conversely, suppressing FOXC1 impeded ESCC stemness induced by IGF-1. The presence of a positive feedback loop, denoted by IGF-1-FOXC1-IGF-1R, suggests the potential of FOXC1 as a prognostic biomarker for ESCC. Taken together, targeting the IGF-1-FOXC1-IGF-1R axis emerges as a promising approach for anti-CSC therapy in ESCC.