TGIF1 functions as a tumor suppressor in pancreatic ductal adenocarcinoma

Discovering the Potential Role of the C2 DUSP2+ MCs Subgroup in Lung Adenocarcinoma

OBJECTIVE

In both industrialized and developing nations worldwide, lung adenocarcinoma is one of the deadliest malignant tumors and the primary cause of cancer-related deaths. Its cellular heterogeneity is unclear to the fullest extent, although in recent years, its prevalence in younger individuals has increased. Therefore, it is urgent to deepen the understanding of lung adenocarcinoma and explore new therapeutic methods.

METHODS

CytoTRACE, Monocle, SCENIC, and enrichment analysis were used to analyze the single cell RNA data, we characterized the biological characteristics of mast cells (MCs) in lung adenocarcinoma patient samples. CellChat was used to analyze and validate the interaction between MCs and tumor cells in lung adenocarcinoma. Prognostic models were used to evaluate and predict the development trend and outcome of a patient's disease, such as the survival time of cancer patients. The python package SCENIC was used to evaluate the enrichment of transcription factors and the activity of regulators in lung adenocarcinoma cell subgroups. CCK-8 assay could validate the activity of a specific cell subgroup sequenced in single cell sequencing to confirm the role of this cell subgroup in tumor proliferation.

RESULTS

Our analysis identified seven major cell types, further grouping MCs within them and identifying four distinct subgroups, including MCs with high DUSP2 expression, which showed some tumor-related characteristics. In addition, we identified the key signaling receptor EGFR and validated it through in vitro knockdown experiments, demonstrating its role in promoting cancer. In addition, we established an independent prognostic indicator, the DUSP2+ MCs risk score, which showed an association between groups with high risk scores and poor outcomes.

CONCLUSION

These findings shed light on the complex interactions in the lung adenocarcinoma tumor microenvironment and suggest that targeting specific MCs subgroups, particularly through the EGFR signaling pathway, may provide new therapeutic strategies.

Metastatic organotropism in small cell lung cancer

Metastasis is the leading cause of cancer-related deaths, yet its regulatory mechanisms are not fully understood. Small-cell lung cancer (SCLC) is the most metastatic form of lung cancer, with most patients presenting with widespread disease, making it an ideal model for studying metastasis. However, the lack of suitable preclinical models has limited such studies. We utilized rapid autopsy-derived tumors to develop xenograft models that mimic key features of SCLC, including histopathology, rapid and widespread development of metastasis to the liver, brain, adrenal, bone marrow, and kidneys within weeks, and response to chemotherapy. By integrating in vivo lineage selection with comprehensive bulk and single cell multiomic profiling of transcriptomes and chromatin accessibility, we identified critical cellular programs driving metastatic organotropism to the liver and brain, the most common sites of SCLC metastasis. Our findings reveal the key role of nuclear-cytoskeletal interactions in SCLC liver metastasis. Specifically, the loss of the nuclear envelope protein lamin A/C, encoded by the LMNA gene, increased nuclear deformability and significantly increased the incidence of liver metastasis. Human liver metastases exhibited reduced LMNA expression compared to other metastatic sites, correlating with poorer patient outcomes and increased mortality. This study introduces novel preclinical models for SCLC metastasis and highlights pathways critical for organ-specific metastasis, offering new avenues for the development of targeted therapies to prevent or treat metastatic disease.

Phosphorylation of TG-interacting factor 1 at carboxyl-terminal sites in response to insulin regulates adipocyte differentiation

TG-interacting factor 1 (TGIF1) contributes to the differentiation of murine white preadipocyte and human adipose tissue-derived stem cells; however, its regulation is not well elucidated. Insulin is a component of the adipogenic cocktail that induces ERK signaling. TGIF1 phosphorylation and sustained stability in response to insulin were reduced through the use of specific MEK inhibitor U0126. Mutagenesis at T235 or T239 residue of TGIF1 in preadipocytes led to dephosphorylation of TGIF1. The reduced TGIF1 stability resulted in an increase in p27kip1 expression, a decrease in phosphorylated Rb expression and cellular proliferation, and a reduced accumulation of lipids compared to the TGIF1-overexpressed cells. These findings highlight that insulin/ERK-driven phosphorylation of the T235 or T239 residue at TGIF1 is crucial for adipocyte differentiation.

Inferring regulators of cell identity in the human adult pancreas

Cellular identity during development is under the control of transcription factors that form gene regulatory networks. However, the transcription factors and gene regulatory networks underlying cellular identity in the human adult pancreas remain largely unexplored. Here, we integrate multiple single-cell RNA-sequencing datasets of the human adult pancreas, totaling 7393 cells, and comprehensively reconstruct gene regulatory networks. We show that a network of 142 transcription factors forms distinct regulatory modules that characterize pancreatic cell types. We present evidence that our approach identifies regulators of cell identity and cell states in the human adult pancreas. We predict that HEYL, BHLHE41 and JUND are active in acinar, beta and alpha cells, respectively, and show that these proteins are present in the human adult pancreas as well as in human induced pluripotent stem cell (hiPSC)-derived islet cells. Using single-cell transcriptomics, we found that JUND represses beta cell genes in hiPSC-alpha cells. BHLHE41 depletion induced apoptosis in primary pancreatic islets. The comprehensive gene regulatory network atlas can be explored interactively online. We anticipate our analysis to be the starting point for a more sophisticated dissection of how transcription factors regulate cell identity and cell states in the human adult pancreas.

Mechanistic elucidation of Juglanthraquinone C targeting breast Cancer: A network Pharmacology-based investigation

Breast cancer is the leading cause of death among women worldwide. Despite the recent treatment options like surgery, chemotherapy etc. the lethality of breast cancer is alarming. Natural compounds are considered a better treatment option against breast carcinoma because of their lower side effects and specificity in targeting important proteins involved in the aberrant activation of pathways in breast cancer. A recently discovered compound called Juglanthraquinone C, which is found in the bark of the Juglans mandshurica Maxim (Juglandaceae) tree has shown promising cytotoxicity in hepatocellular carcinoma. However, not much data is available on the molecular mechanisms followed by this compound. Therefore, we aimed to investigate the molecular mechanism followed by Juglanthraquinone C against breast cancer. We used the network pharmacology technique to analyse the mechanism of action of Juglanthraquinone C in breast cancer and validated our study by applying various computational tools such as UALCAN, cBioportal, TIMER, docking and simulation. The results showed the compound and breast cancer target network shared 31 common targets. Moreover, we observed that Juglanthraquinone C targets multiple deregulated genes in breast cancer such as TP53, TGIF1, IGF1R, SMAD3, JUN, CDC42, HBEGF, FOS and signaling pathways such as PI3K-Akt pathway, TGF-β signaling pathway, MAPK pathway and HIPPO signaling pathway. A docking examination revealed that the investigated drug had a high affinity for the primary target TGIF1 protein. A stable protein-ligand combination was generated by the best hit molecule, according to molecular dynamics modeling. The main aim of this study was to examine Juglanthraquinone C's significance as a prospective breast cancer treatment and to better understand the molecular mechanism this substance uses in breast cancer since there is a need to discover new therapeutics to decrease the load on current therapeutics which also are currently ineffective due to several side effects and development of drug resistance.

Antagonism between Prdm16 and Smad4 specifies the trajectory and progression of pancreatic cancer

The transcription factor Prdm16 functions as a potent suppressor of transforming growth factor-beta (TGF-β) signaling, whose inactivation is deemed essential to the progression of pancreatic ductal adenocarcinoma (PDAC). Using the KrasG12D-based mouse model of human PDAC, we surprisingly found that ablating Prdm16 did not block but instead accelerated PDAC formation and progression, suggesting that Prdm16 might function as a tumor suppressor in this malignancy. Subsequent genetic experiments showed that ablating Prdm16 along with Smad4 resulted in a shift from a well-differentiated and confined neoplasm to a highly aggressive and metastatic disease, which was associated with a striking deviation in the trajectory of the premalignant lesions. Mechanistically, we found that Smad4 interacted with and recruited Prdm16 to repress its own expression, therefore pinpointing a model in which Prdm16 functions downstream of Smad4 to constrain the PDAC malignant phenotype. Collectively, these findings unveil an unprecedented antagonistic interaction between the tumor suppressors Smad4 and Prdm16 that functions to restrict PDAC progression and metastasis.

Deciphering epithelial-to-mesenchymal transition in pancreatic cancer

Epithelial to mesenchymal transition (EMT) is a complex cellular program that alters epithelial cells and induces their transformation into mesenchymal cells. While essential to normal developmental processes such as embryogenesis and wound healing, EMT has also been linked to the development and progression of various diseases, including fibrogenesis and tumorigenesis. Under homeostatic conditions, initiation of EMT is mediated by key signaling pathways and pro-EMT-transcription factors (EMT-TFs); however, in certain contexts, these pro-EMT regulators and programs also drive cell plasticity and cell stemness to promote oncogenesis as well as metastasis. In this review, we will explain how EMT and EMT-TFs mediate the initiation of pro-cancer states and how they influence late-stage progression and metastasis in pancreatic ductal adenocarcinoma (PDAC), the most severe form of pancreatic cancer.

Epithelial to Mesenchymal Transition as Mechanism of Progression of Pancreatic Cancer: From Mice to Men

Owed to its aggressive yet subtle nature, pancreatic cancer remains unnoticed till an advanced stage so that in most cases the diagnosis is made when the cancer has already spread to other organs with deadly efficiency. The progression from primary tumor to metastasis involves an intricate cascade of events comprising the pleiotropic process of epithelial to mesenchymal transition (EMT) facilitating cancer spread. The elucidation of this pivotal phenotypic change in cancer cell morphology, initially heretic, moved from basic studies dissecting the progression of pancreatic cancer in animal models to move towards human disease, although no clinical translation of the concept emerged yet. Despite this transition, a full-blown mesenchymal phenotype may not be accomplished; rather, the plasticity of the program and its dependency on heterotopic signals implies a series of fluctuating modifications of cancer cells encompassing mesenchymal and epithelial features. Despite the evidence supporting the activation of EMT and MET during cancer progression, our understanding of the relationship between tumor microenvironment and EMT is not yet mature for a clinical application. In this review, we attempt to resume the knowledge on EMT and pancreatic cancer, aiming to include the EMT among the hallmarks of cancer that could potentially modify our clinical thinking with the purpose of filling the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers, as well as their application for prognostic and predictive purposes.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

Silencing of histone deacetylase 3 suppresses the development of esophageal squamous cell carcinoma through regulation of miR-494-mediated TGIF1

BACKGROUND

Deacetylation of histones by histone deacetylase 3 (HDAC3) acts importantly in modulating apoptosis, DNA damage and cellular progression. Herein, we aimed to unravel the functional role of HDAC3 in a lethal disease, esophageal squamous cell carcinoma (ESCC).

METHODS

The expression of HDAC3 in clinically collected ESCC tissues was determined by RT-qPCR and immunohistochemistry. As revealed from bioinformatics analysis, the putative relations between HDAC3 and microRNA-494 (miR-494) and between miR-494 and transforming growth factor beta (TGFβ)-inducing factor 1 (TGIF1) were further verified by chromatin immunoprecipitation and dual-luciferase reporter gene assay. Functional roles of shRNA-mediated depletion of HDAC3, miR-494 mimic and overexpressed TGIF1 were explored by gain- and loss-of-function assays with regard to ESCC cell biological behaviors. A nude mouse model of ESCC was developed for in vivo validation.

RESULTS

HDAC3 was highly expressed in ESCC tissues, suggestive of poor prognosis while TGIF1 was upregulated and miR-494 was downregulated. Mechanistic investigation revealed that HDAC3 inhibited miR-494 expression and TGIF1 was a direct target of miR-494. Furthermore, silencing HDAC3 or overexpressing miR-494 was demonstrated to suppress aggressive phenotypes of ESCC cells both in vitro through the activated TGFβ signaling pathway and in vivo, while TGIF1 overexpression induced opposite results.

CONCLUSION

Collectively, our findings provided demonstration regarding the oncogenic property of HDAC3 in ESCC via the miR-494/TGIF1/TGFβ axis.

Loss of IRF7 accelerates acute myeloid leukemia progression and induces VCAM1-VLA-4 mediated intracerebral invasion

Interferon regulatory factor 7 (IRF7) is widely studied in inflammatory models. Its effects on malignant progression have been documented mainly from the perspective of the microenvironment. However, its role in leukemia has not been established. Here we used MLL-AF9-induced acute myeloid leukemia (AML) mouse models with IRF7 knockout or overexpression and xenograft mouse models to explore the intrinsic effects of IRF7 in AML. AML-IRF7^−/− mice exhibited accelerated disease progression with intracerebral invasion of AML cells. AML-IRF7^−/− cells showed increased proliferation and elevated leukemia stem cell (LSC) levels. Overexpression of IRF7 in AML cells decreased cell proliferation and LSC levels. Furthermore, overexpression of transforming growth-interacting factor 1 (TGIF1) rescued the enhanced proliferation and high LSC levels caused by IRF7 deficiency. Moreover, upregulation of vascular cell adhesion molecule 1 (VCAM1), which correlated with high LSC levels, was detected in AML-IRF7^−/− cells. In addition, blocking VCAM1-very late antigen 4 (VLA-4) axis delayed disease progression and attenuated intracerebral invasion of AML cells. Therefore, our findings uncover the intrinsic effects of IRF7 in AML and provide a potential strategy to control central nervous system myeloid leukemia.

Structural Insight into the Binding of TGIF1 to SIN3A PAH2 Domain through a C-Terminal Amphipathic Helix

TGIF1 is a transcriptional repressor playing crucial roles in human development and function and is associated with holoprosencephaly and various cancers. TGIF1-directed transcriptional repression of specific genes depends on the recruitment of corepressor SIN3A. However, to date, the exact region of TGIF1 binding to SIN3A was not clear, and the structural basis for the binding was unknown. Here, we demonstrate that TGIF1 utilizes a C-terminal domain (termed as SIN3A-interacting domain, SID) to bind with SIN3A PAH2. The TGIF1 SID adopts a disordered structure at the apo state but forms an amphipathic helix binding into the hydrophobic cleft of SIN3A PAH2 through the nonpolar side at the holo state. Residues F379, L382 and V383 of TGIF1 buried in the hydrophobic core of the complex are critical for the binding. Moreover, homodimerization of TGIF1 through the SID and key residues of F379, L382 and V383 was evidenced, which suggests a dual role of TGIF1 SID and a correlation between dimerization and SIN3A-PAH2 binding. This study provides a structural insight into the binding of TGIF1 with SIN3A, improves the knowledge of the structure–function relationship of TGIF1 and its homologs and will help in recognizing an undiscovered SIN3A-PAH2 binder and developing a peptide inhibitor for cancer treatment.

TGIF1 plays a carcinogenic role in esophageal squamous cell carcinoma through the Wnt/β‑catenin and Akt/mTOR signaling pathways

TGFB induced factor homeobox 1 (TGIF1), a transcriptional corepressor, has been reported to be involved in tumorigenesis and cancer development. However, the role of TGIF1 in the growth and metastasis of esophageal cancer is poorly studied. In the present study, it was found that TGIF1 was highly expressed in esophageal cancer tissues and cell lines. The silencing of TGIF1 by siRNA interference significantly inhibited the proliferation, migration, invasion and epithelial‑mesenchymal transition (EMT) process of KYSE‑150 esophageal cancer cells, and promoted cell apoptosis. Correspondingly, the upregulation of TGIF1 significantly promoted the proliferation and metastatic potential of Eca‑109 cells, and reduced apoptosis. Furthermore, the data indicated that the Wnt/β‑catenin and Akt/mammalian target of rapamycin (mTOR) signaling pathways were inhibited by TGIF1 knockdown, and were promoted by the overexpression of TGIF1. It was also confirmed that TGIF1 knockdown reduced tumor growth, inhibited Wnt/β‑catenin and Akt/mTOR pathway activation, and reversed the TGF‑β1‑mediated EMT process in a tumor xenograft model. Taken together, the data of the present study suggest that TGIF1 plays an oncogenic role in the progression of esophageal cancer. It may carry out this role by regulating the Wnt/β‑catenin and Akt/mTOR signaling pathways.

Use of signals of positive and negative selection to distinguish cancer genes and passenger genes

A major goal of cancer genomics is to identify all genes that play critical roles in carcinogenesis. Most approaches focused on genes positively selected for mutations that drive carcinogenesis and neglected the role of negative selection. Some studies have actually concluded that negative selection has no role in cancer evolution. We have re-examined the role of negative selection in tumor evolution through the analysis of the patterns of somatic mutations affecting the coding sequences of human genes. Our analyses have confirmed that tumor suppressor genes are positively selected for inactivating mutations, oncogenes, however, were found to display signals of both negative selection for inactivating mutations and positive selection for activating mutations. Significantly, we have identified numerous human genes that show signs of strong negative selection during tumor evolution, suggesting that their functional integrity is essential for the growth and survival of tumor cells.

Human Papillomavirus 16 (HPV16) E2 Repression of TWIST1 Transcription Is a Potential Mediator of HPV16 Cancer Outcomes

HPV16-positive cancers have a better clinical outcome that their non-HPV anatomical counterparts. Furthermore, the presence of HPV16 E2 RNA predicts a better outcome for HPV16-positive tumors; the reasons for this are not known.

Human papillomaviruses (HPVs) are causative agents in around 5% of all cancers, including cervical and oropharyngeal. A feature of HPV cancers is their better clinical outcome compared with non-HPV anatomical counterparts. In turn, the presence of E2 predicts a better clinical outcome in HPV-positive cancers; the reason(s) for the better outcome of E2-positive patients is not fully understood. Previously, we demonstrated that HPV16 E2 regulates host gene transcription that is relevant to the HPV16 life cycle in N/Tert-1 cells. One of the genes repressed by E2 and the entire HPV16 genome in N/Tert-1 cells is TWIST1. Here, we demonstrate that TWIST1 RNA levels are reduced in HPV-positive versus HPV-negative head and neck cancer and that E2 and HPV16 downregulate both TWIST1 RNA and protein in our N/Tert-1 model; E6/E7 cannot repress TWIST1. E2 represses the TWIST1 promoter in transient assays and is localized to the TWIST1 promoter; E2 also induces repressive epigenetic changes on the TWIST1 promoter. TWIST1 is a master transcriptional regulator of the epithelial to mesenchymal transition (EMT), and a high level of TWIST1 is a prognostic marker indicative of poor cancer outcomes. We demonstrate that TWIST1 target genes are also downregulated in E2-positive N/Tert-1 cells and that E2 promotes a failure in wound healing, a phenotype of low TWIST1 levels. We propose that the presence of E2 in HPV-positive tumors leads to TWIST1 repression and that this plays a role in the better clinical response of E2-positive HPV tumors.

IMPORTANCE HPV16-positive cancers have a better clinical outcome that their non-HPV anatomical counterparts. Furthermore, the presence of HPV16 E2 RNA predicts a better outcome for HPV16-positive tumors; the reasons for this are not known. Here, we demonstrate that E2 represses expression of the TWIST1 gene; an elevated level of this gene is a marker of poor prognosis for a variety of cancers. We demonstrate that E2 directly binds to the TWIST1 promoter and actively represses transcription. TWIST1 is a master regulator promoting EMT, and here, we demonstrate that the presence of E2 reduces the ability of N/Tert-1 cells to wound heal. Overall, we propose that the E2 repression of TWIST1 may contribute to the better clinical outcome of E2-positive HPV16-positive tumors.

Aberrant super-enhancer landscape reveals core transcriptional regulatory circuitry in lung adenocarcinoma

Lung adenocarcinoma (LUAD) relies on dysregulated gene expression to sustain its infinite growth and progression. Emerging evidence indicates that aberrant transcriptional program results from core transcriptional regulatory circuitry (CRC) which is driven by super-enhancers (SEs). In this study, by integrating profiles of H3K27Ac chromatin immunoprecipitation sequencing (ChIP-seq) from normal adult lung and LUAD cell lines, we revealed that widespread alterations of the super-enhancer were presence during lung carcinogenesis. With SE-based modeling of regulatory circuits and assessments of transcription factor (TF) dependencies, we reconstructed an interconnected transcriptional regulation network formed by three master TFs, including ELF3, EHF, and TGIF1, all of which promoted each other’s expression that confirmed by ChIP-qPCR and western blot. Loss-of function assay revealed that each of them is essential for LUAD cells survival, invasion and metastasis. Meanwhile, the rescue assay also illustrated the transacting transcriptional regulatory circuitry. In addition, the mRNA levels of ELF3, EHF, and TGIF1 were differentially expressed in LUAD tumors and peritumoral tissue. IHC of serial sections revealed that high expressions of CRC (ELF3/EHF/TGIF1-High) were closely associated with high proliferative activity in tumor tissue and poor prognosis on patients with LUAD. Finally, we used small molecular inhibitors to perturb the transcriptional circuitry, also exhibited a prominent anti-cancer effect in vitro. Our findings reveal the mechanism of the transcriptional dysregulation and addiction of LUAD.

TGIF1-Twist1 axis in pancreatic ductal adenocarcinoma

TG-interacting factor 1 (TGIF1) exerts inhibitory effects on transforming growth factor-beta (TGF-β) signaling by suppressing Smad signaling pathway at multiple levels. TGIF1 activity is important for normal embryogenesis and organogenesis, yet its dysregulation can culminate in tumorigenesis. For instance, increased expression of TGIF1 correlates with poor prognosis in triple-negative breast cancer patients, and enforced expression of TGIF1 facilitates Wnt-driven mammary tumorigenesis, suggesting that TGIF1 might function as an oncoprotein. Quite surprisingly, TGIF1 has recently been shown to function as a tumor suppressor in pancreatic ductal adenocarcinoma (PDAC), possibly owing to its ability to antagonize the pro-malignant transcription factor Twist1. In this article, we will briefly elaborate on the biological and clinical significance of the unique tumor-suppressive function of TGIF1 and its functional interaction with Twist1 in the context of PDAC pathogenesis and progression.

Differences between KC and KPC pancreatic ductal adenocarcinoma mice models, in terms of their modeling biology and their clinical relevance

Pancreatic ductal adenocarcinoma (PDAC) is among the dangerous human cancers, is the 10th highly prevalent cancer, and the fourth sole cause of cancer-related mortality in the United States of America. Notwithstanding the significant commitment, the forecast for people with this burden continues to have a five-year survival rate of just 4-6%. The most critical altered genes within PDAC consist of K-ras the proto-oncogene which is usually mutationally activated above 90% cases and tumor suppressors likeTrp53 are altered at 55%. To face the burden of pancreatic ductal adenocarcinoma, a variety of genetically engineered pancreatic cancer mice models have been created over the last past years. These models have distinctive features and are not all appropriate for preclinical studies. In this review, we focus on differences between two mice models K-ras^LSL.G12D/+;Pdx-1-Cre(KC) and K-ras^LSL.G12D/+; Trp53^R172H/+; Pdx-1-Cre(KPC) in terms of their modeling biology and their clinical relevance.

Prognostic value of leukemia inhibitory factor and its receptor in pancreatic adenocarcinoma

Currently, the prognostic effects of leukemia inhibitory factor (LIF) and LIF receptor (LIFR) in pancreatic adenocarcinoma (PAAD) are not clear. In the present study, we utilized the large datasets from four public databases to investigate the expression of LIF and LIFR and their clinical significance in PAAD. Eight cohorts containing 1278 cases with PAAD were identified and the analysis results suggested that LIF was highly expressed while LIFR was lowly expressed in PAAD tissues compared with adjacent or normal tissues. Kaplan-Meier plot curves and univariate and multivariate Cox proportional hazards regression analyses indicated high LIF expression was associated with shorter overall survival (adjusted hazard ratio = 1.641, 95% CI: 1.399-1.925, p < 0.001) whereas high LIFR expression was associated with longer overall survival (adjusted hazard ratio = 0.653, 95% CI: 0.517-0.826, p < 0.001).

TWIST1 transcriptionally regulates glycolytic genes to promote the Warburg metabolism in pancreatic cancer

Reprogrammed glucose metabolism is essential for tumor initiation and development, especially for pancreatic ductal adenocarcinoma (PDAC). Most cancer cells rely on aerobic glycolysis, a phenomenon termed "the Warburg effect", to support uncontrolled proliferation and evade apoptosis. However, the direct regulators of the Warburg effect remain areas of active investigation. In this study, we found that the highly conserved transcription factor, TWIST1, is a crucial regulator of aerobic glycolysis in PDAC. Genetic silencing of TWIST1 significantly inhibited the glycolytic phenotypes of PDAC cells as revealed by reduced glucose uptake, lactate production, and extracellular acidification rate, which can be restored by re-expression of siRNA-resistant TWIST1. Moreover, tamoxifen-inducible expression of TWIST1 promoted the Warburg metabolism of PDAC cells. Mechanistically, by luciferase reporter assay and chromatin immunoprecipitation experiment, we showed that TWIST1 can directly increase the expression of several glycolytic genes, including SLC2A1, HK2, ENO1, and PKM2. Of note, the transcriptional regulation by TWIST1 was not dependent on HIF1α or c-Myc. In The Cancer Genome Atlas and Gene Expression Omnibus accession GSE15471, we confirmed that TWIST1 was closely associated with the glycolysis pathway. Collectively, our findings indicate that TWIST1 is likely to act as important regulator of the Warburg effect in PDAC.