Compound C620-0696, a new potent inhibitor targeting BPTF, the chromatin-remodeling factor in non-small-cell lung cancer

A BPTF-specific PROTAC degrader enhances NK cell-based cancer immunotherapy

Natural killer (NK) cell-based immunotherapy shows promise in cancer treatment, but its efficacy remains limited, necessitating the development of novel strategies. In this study, we demonstrate that the epigenetic factor bromodomain PHD-finger containing transcription factor (BPTF) hinders hepatocellular carcinoma (HCC) recognition by NK cells through its PHD finger's interpretation of H3K4me3. We have generated a small-molecule proteolysis-targeting chimera (PROTAC) that selectively degrades human and murine BPTF. The degradation of BPTF using PROTACs directly enhances the abundance of natural cytotoxicity receptor ligands on HCC cells, facilitating their recognition by NK cells and thereby augmenting NK cell cytotoxicity against HCC both in vitro and in vivo. Through multidisciplinary techniques, our findings establish targeting BPTF with PROTACs as a promising approach to overcome immune evasion of HCC from NK cells and provide a new strategy to enhance NK cell-based cancer immunotherapy.

Chromatin accessibility: biological functions, molecular mechanisms and therapeutic application

The dynamic regulation of chromatin accessibility is one of the prominent characteristics of eukaryotic genome. The inaccessible regions are mainly located in heterochromatin, which is multilevel compressed and access restricted. The remaining accessible loci are generally located in the euchromatin, which have less nucleosome occupancy and higher regulatory activity. The opening of chromatin is the most important prerequisite for DNA transcription, replication, and damage repair, which is regulated by genetic, epigenetic, environmental, and other factors, playing a vital role in multiple biological progresses. Currently, based on the susceptibility difference of occupied or free DNA to enzymatic cleavage, solubility, methylation, and transposition, there are many methods to detect chromatin accessibility both in bulk and single-cell level. Through combining with high-throughput sequencing, the genome-wide chromatin accessibility landscape of many tissues and cells types also have been constructed. The chromatin accessibility feature is distinct in different tissues and biological states. Research on the regulation network of chromatin accessibility is crucial for uncovering the secret of various biological processes. In this review, we comprehensively introduced the major functions and mechanisms of chromatin accessibility variation in different physiological and pathological processes, meanwhile, the targeted therapies based on chromatin dynamics regulation are also summarized.

Epigenetics-targeted drugs: current paradigms and future challenges

Epigenetics governs a chromatin state regulatory system through five key mechanisms: DNA modification, histone modification, RNA modification, chromatin remodeling, and non-coding RNA regulation. These mechanisms and their associated enzymes convey genetic information independently of DNA base sequences, playing essential roles in organismal development and homeostasis. Conversely, disruptions in epigenetic landscapes critically influence the pathogenesis of various human diseases. This understanding has laid a robust theoretical groundwork for developing drugs that target epigenetics-modifying enzymes in pathological conditions. Over the past two decades, a growing array of small molecule drugs targeting epigenetic enzymes such as DNA methyltransferase, histone deacetylase, isocitrate dehydrogenase, and enhancer of zeste homolog 2, have been thoroughly investigated and implemented as therapeutic options, particularly in oncology. Additionally, numerous epigenetics-targeted drugs are undergoing clinical trials, offering promising prospects for clinical benefits. This review delineates the roles of epigenetics in physiological and pathological contexts and underscores pioneering studies on the discovery and clinical implementation of epigenetics-targeted drugs. These include inhibitors, agonists, degraders, and multitarget agents, aiming to identify practical challenges and promising avenues for future research. Ultimately, this review aims to deepen the understanding of epigenetics-oriented therapeutic strategies and their further application in clinical settings.

Circ_100549 promotes tumor progression in lung adenocarcinoma through upregulation of BIRC6

Lung adenocarcinoma (LUAD) is a subtype of lung cancer with high incidence and mortality globally. Emerging evidence suggests that circular RNAs (circRNAs) exert critical functions in human cancers, including LUAD. CircRNA_100549 (circ_100549) has been reported to be significantly upregulated in non-small cell lung cancer (NSCLC) samples, while its role in modulating LUAD progression remains to be explored. The current study aims at investigating the functional roles of circ_100549 in LUAD and its downstream molecular mechanism. First, we found that the expression of circ_100549 was higher in LUAD cell lines. Loss-of-function assays verified that depletion of circ_100549 repressed LUAD cell proliferation but accelerated cell apoptosis. Furthermore, in vivo experiments demonstrated that silencing of circ_100549 suppressed tumor growth. Subsequently, based on database analysis, we carried out a series of experiments to explore the mechanisms and effects of circ_100549 underlying LUAD progression, including RNA-binding protein immunoprecipitation (RIP), RNA/DNA pull-down, luciferase reporter, and chromatin immunoprecipitation (ChIP) assays. The results indicated that circ_100549 serves as a ceRNA by sponging miR-95-5p to upregulate BPTF expression, thus upregulating BIRC6 expression at a transcriptional level in LUAD. In summary, our study demonstrated that circ_100549 facilitates LUAD progression by upregulating BIRC6 expression.

BPTF cooperates with MYCN and MYC to link neuroblastoma cell cycle control to epigenetic cellular states

The nucleosome remodeling factor BPTF is required for the deployment of the MYC-driven transcriptional program. Deletion of one Bptf allele delays tumor progression in mouse models of pancreatic cancer and lymphoma. In neuroblastoma, MYCN cooperates with the transcriptional core regulatory circuitry (CRC). High BPTF levels are associated with high-risk features and decreased survival. BPTF depletion results in a dramatic decrease of cell proliferation. Bulk RNA-seq, single-cell sequencing, and tissue microarrays reveal a positive correlation of BPTF and CRC transcription factor expression. Immunoprecipitation/mass spectrometry shows that BPTF interacts with MYCN and the CRC proteins. Genome-wide distribution analysis of BPTF and CRC in neuroblastoma reveals a dual role for BPTF: 1) it co-localizes with MYCN/MYC at the promoter of genes involved in cell cycle and 2) it co-localizes with the CRC at super-enhancers to regulate cell identity. The critical role of BPTF across neuroblastoma subtypes supports its relevance as a therapeutic target.

Unraveling the allosteric inhibition mechanism of PARP-1 CAT and the D766/770A mutation effects via Gaussian accelerated molecular dynamics and Markov state model

PARP-1 (Poly (ADP-ribose) polymerase 1) is a nuclear enzyme and plays a key role in many cellular functions, such as DNA repair, modulation of chromatin structure, and recombination. Developing the PARP-1 inhibitors has emerged as an effective therapeutic strategy for a growing list of cancers. The catalytic structural domain (CAT) of PARP-1 upon binding the inhibitor allosterically regulates the conformational changes of helix domain (HD), affecting its identification with the damaged DNA. The typical type I (EB47) and III (veliparib) inhibitors were able to lengthening or shortening the retention time of this enzyme on DNA damage and thus regulating the cytotoxicity. Nonetheless, the basis underlying allosteric inhibition is unclear, which limits the development of novel PARP-1 inhibitors. Here, to investigate the distinct allosteric changes of EB47 and veliparib against PARP-1 CAT, each complex was simulated via classical and Gaussian accelerated molecular dynamics (cMD and GaMD). To study the reverse allosteric basis and mutation effects, the complexes PARP-1 with UKTT15 and PARP-1 D766/770A mutant with EB47 were also simulated. Importantly, the markov state models were built to identify the transition pathways of crucial substates of allosteric communication and the induction basis of PARP-1 reverse allostery. The conformational change differences of PARP-1 CAT regulated by allosteric inhibitors were concerned with to their interaction at the active site. Energy calculations suggested the energy advantage of EB47 in inhibiting the wild-type PARP-1, compared with D766/770A PARP-1. Secondary structure results showed the change of two key loops (αB-αD and αE-αF) in different systems. This work reported the basis of PARP-1 allostery from both thermodynamic and kinetic views, providing the guidance for the discovery and design of more innovative PARP-1 allosteric inhibitors.

An alternative NURF complex sustains acute myeloid leukemia by regulating the accessibility of insulator regions

Efficient treatment of acute myeloid leukemia (AML) patients remains a challenge despite recent therapeutic advances. Here, using a CRISPRi screen targeting chromatin factors, we identified the nucleosome-remodeling factor (NURF) subunit BPTF as an essential regulator of AML cell survival. We demonstrate that BPTF forms an alternative NURF chromatin remodeling complex with SMARCA5 and BAP18, which regulates the accessibility of a large set of insulator regions in leukemic cells. This ensures efficient CTCF binding and boundary formation between topologically associated domains that is essential for maintaining the leukemic transcriptional programs. We also demonstrate that the well-studied PHD2-BROMO chromatin reader domains of BPTF, while contributing to complex recruitment to chromatin, are dispensable for leukemic cell growth. Taken together, our results uncover how the alternative NURF complex contributes to leukemia and provide a rationale for its targeting in AML.

BPTF in bone marrow provides a potential progression biomarker regulated by TFAP4 through the PI3K/AKT pathway in neuroblastoma

BACKGROUND

Neuroblastoma (NB) is the most common extracranial malignant solid tumor in children, which is highly prone to bone marrow (BM) metastasis. BM can monitor early signs of mild disease and metastasis. Existing biomarkers are insufficient for the diagnosis and treatment of NB. Bromodomain PHD finger transcription factor (BPTF) is an important subunit of the chromatin-remodeling complex that is closely associated with tumors. Here, we evaluated whether BPTF in BM plays an important role in predicting NB progression, and explore the molecular mechanism of BPTF in NB.

METHODS

The clinical relevance of the BPTF was predicted in the GEO (GSE62564) and TARGET database. The biological function of BPTF in NB was investigated by constructing cell lines and employing BPTF inhibitor AU1. Western blot was used to determine the changes of BPTF, TFAP4, PI3K/AKT signaling and Epithelial-mesenchymal transition (EMT) related markers. A total of 109 children with newly diagnosed NB in Beijing Children's Hospital from January 2018 to March 2021 were included in this study. RT-PCR was used to measure the BPTF and TFAP4 expression in BM. The cut-off level was set at the median value of BPTF expression levels.

RESULTS

Databases suggested that BPTF expression was higher in NB and was significantly associated with stage and grade. Proliferation and migration of NB cells were slowed down when BPTF was silenced. Mechanistically, TFAP4 could positively regulate BPTF and promotes EMT process through activating the PI3K/AKT signaling pathway. Moreover, detection of the newly diagnosed BM specimens showed that BPTF expression was significantly higher in high-risk group, stage IV group and BM metastasis group. Children with high BPTF at initial diagnosis were considered to have high risk for disease progression and recurrence. BPTF is an independent risk factor for predicting NB progression.

CONCLUSIONS

A novel and convenient BPTF-targeted humoral detection that can prompt minimal residual and predict NB progression in the early stages of the disease were identified. BPTF inhibitor AU1 is expected to become a new targeted drug for NB therapy. It's also reveal previously unknown mechanisms of BPTF in NB cell proliferation and metastasis through TFAP4 and PI3K/AKT pathways.

Discovery of new small molecule inhibitors of the BPTF bromodomain

Chromatin remodeling regulates many basic cellular processes, such as gene transcription, DNA repair, and programmed cell death. As the largest member of nucleosome remodeling factor (NURF), BPTF plays a vital role in the occurrence and development of cancer. Currently, BPTF bromodomain inhibitors are still in development. In this study, by conducting homogenous time-resolved fluorescence resonance energy transfer (HTRF) assay, we identified a potential, novel BPTF inhibitor scaffold Sanguinarine chloride with the IC₅₀ value of 344.2 ± 25.1 nM. Biochemical analysis revealed that compound Sanguinarine chloride exhibited high binding affinity to the BPTF bromodomain. Molecular docking predicted the binding mode of Sanguinarine chloride and elucidated the activities of its derivatives. Moreover, Sanguinarine chloride showed a potent anti-proliferative effect in MIAPaCa-2 cells and inhibited the expression of BPTF target gene c-Myc. Taken together, Sanguinarine chloride provides a qualified chemical tool for developing potent BPTF bromodomain inhibitors.

Targeting BPTF Sensitizes Pancreatic Ductal Adenocarcinoma to Chemotherapy by Repressing ABC-Transporters and Impairing Multidrug Resistance (MDR)

Simple Summary

Pancreatic ductal adenocarcinoma is a devastating disease and an extremely chemoresistant tumour. In the present manuscript, we described the role of BPTF during tumour pancreatic ductal adenocarcinoma progression and in response to gemcitabine treatment, a gold standard treatment in this tumour type. Through different genetic approaches, we reduced BPTF levels in a panel of pancreatic ductal adenocarcinoma cell lines. We validated its therapeutic effect in cell cultures and in mouse models of pancreatic cancer. A reduction in BPTF levels impaired cell proliferation and sensitized pancreatic tumour cells to gemcitabine. We demonstrated that BPTF-silencing reduced the expression of several ABC-transporters, which are involved in gemcitabine resistance, and enhanced its accumulation in the tumour cell, improving its therapeutic effect.

Abstract

Pancreatic ductal adenocarcinoma (PDA) is characterized by an extremely poor prognosis due to its late diagnosis and strong chemoresistance to the current treatments. Therefore, finding new therapeutic targets is an urgent need nowadays. In this study, we report the role of the chromatin remodeler BPTF (Bromodomain PHD Finger Transcription Factor) as a therapeutic target in PDA. BPTF-silencing dramatically reduced cell proliferation and migration in vitro and in vivo in human and mouse PDA cell lines. Moreover, BPTF-silencing reduces the IC50 of gemcitabine in vitro and enhanced its therapeutic effect in vivo. Mechanistically, BPTF is required for c-MYC recruitment to the promoter of ABC-transporters and its downregulation facilitates gemcitabine accumulation in tumour cells, increases DNA damage, and a generates a strong synergistic effect in vivo. We show that BPTF is a therapeutic target in pancreatic ductal adenocarcinoma due to its strong effect on proliferation and in response to gemcitabine.

Synthesis of NVS-BPTF-1 and evaluation of its biological activity

BPTF (bromodomain and PHD finger containing transcription factor) is a multidomain protein that plays essential roles in transcriptional regulation, T-cell homeostasis and stem cell pluripotency. As part of the chromatin remodeling complex hNURF (nucleosome remodeling factor), BPTF epigenetic reader subunits are particularly important for BPTF cellular function. Here we report the synthesis of NVS-BPTF-1, a previously reported highly potent and selective BPTF-bromodomain inhibitor. Evaluation of the impact of the inhibition of BPTF-bromodomain using NVS-BPTF-1 on selected proteins involved in the antigen processing pathway revealed that exclusively targeting BPTF-bromodomain is insufficient to observe an increase of PSMB8, PSMB9, TAP1 and TAP2 proteins.

Alternative approaches to target Myc for cancer treatment

The Myc proto-oncogene family consists of three members, C-MYC, MYCN, and MYCL, which encodes the transcription factor c-Myc (hereafter Myc), N-Myc, and L-Myc, respectively. Myc protein orchestrates diverse physiological processes, including cell proliferation, differentiation, survival, and apoptosis. Myc modulates about 15% of the global transcriptome, and its deregulation rewires the cellular signaling modules inside tumor cells, thereby acquiring selective advantages. The deregulation of Myc occurs in >70% of human cancers, and is related to poor prognosis; hence, hyperactivated Myc oncoprotein has been proposed as an ideal drug target for decades. Nevertheless, no specific drug is currently available to directly target Myc, mainly because of its "undruggable" properties: lack of enzymatic pocket for conventional small molecules to bind; inaccessibility for antibody due to the predominant nucleus localization of Myc. Although the topic of targeting Myc has actively been reviewed in the past decades, exciting new progresses in this field keep emerging. In this review, after a comprehensive summarization of valuable sources for potential druggable targets of Myc-driven cancer, we also peer into the promising future of utilizing macropinocytosis to deliver peptides like Omomyc or antibody agents to intracellular compartment for cancer treatment.

β-elemene enhances the antitumor activity of erlotinib by inducing apoptosis through AMPK and MAPK pathways in TKI-resistant H1975 lung cancer cells

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) significantly improve the outcome of non-small-cell lung cancer (NSCLC) patients with EGFR mutations, however, most TKI-treated patients will develop resistance to TKIs. β-elemene, extracted from Curcuma aromatica Salisb., has been widely used to treat various malignant tumors, including TKI-resistant NSCLC, but, the effects and the molecular mechanisms remain unclear. In this study, the NCI-H1975 cell line harboring double mutations L858R/T790M was treated with varying concentrations of β-elemene and/or erlotinib. The effects of β-elemene on cell proliferation, migration, apoptosis, and the expression of relevant proteins of NCI-H1975 cells were evaluated. The results revealed that β‑elemene significantly inhibited the growth, colony formation capacity, wound healing ability of NCI-H1975 cells, and improved the sensitivity of NCI-H1975 cells to erlotinib. Compared with erlotinib alone, β-elemene plus erlotinib significantly promoted the apoptosis of NCI-H1975 cells, accompanied by the down-regulated expression of P-mTOR, P-EGFR, CHOP proteins and up-regulated expression of P-AMPKα and Bax proteins. Taken together, these findings demonstrate that β-elemene suppresses the proliferation and migration of TKI-resistant H1975 cells, and enhances the antitumor activity of erlotinib by inducing apoptosis through AMPK and MAPK pathways in TKI-resistant H1975 lung cancer cells, indicating that β-elemene is a promising anti-cancer therapeutic candidate for TKI-resistant NSCLC.

Upregulation of bromodomain PHD finger transcription factor in ovarian cancer and its critical role for cancer cell proliferation and survival

Bromodomain PHD finger transcription factor (BPTF) is a core subunit of the nucleosome-remodeling factor (NURF) complex, which plays an important role in the development of several cancers. However, it is unknown whether BPTF regulates the progression of ovarian cancer (OC). To investigate this, we measured the relative expression levels of BPTF in OC cell lines and tissues using Western blot and immunohistochemistry, respectively, and the results were analyzed using the χ² test. We also examined the effects from BPTF knockdown on the proliferation, migration, invasiveness, and apoptosis of OC cell lines. Mechanistic studies revealed that these effects were achieved through simultaneous modulation of multiple signaling pathways. We found that BPTF was highly expressed in OC cell lines and tissues compared with a normal human ovarian epithelial cell line and non-cancerous tissues (P < 0.05). These results are also supported by the public RNA-seq data. BPTF overexpression was correlated with a poor prognosis for OC patient survival (P < 0.05). In vitro experiments revealed that the downregulation of BPTF inhibited OC cell proliferation, colony formation, migration, and invasiveness, and induced apoptosis. BPTF knockdown also affected the epithelial-mesenchymal transition (EMT) signaling pathways and induced the cleavage of apoptosis-related proteins. Consequently, BPTF plays a critical role in OC cell survival, and functions as a potential therapeutic target for OC.

Combined Protein- and Ligand-Observed NMR Workflow to Screen Fragment Cocktails against Multiple Proteins: A Case Study Using Bromodomains

As fragment-based drug discovery has become mainstream, there has been an increase in various screening methodologies. Protein-observed ¹⁹F (PrOF) NMR and ¹H CPMG NMR are two fragment screening assays that have complementary advantages. Here, we sought to combine these two NMR-based assays into a new screening workflow. This combination of protein- and ligand-observed experiments allows for a time- and resource-efficient multiplexed screen of mixtures of fragments and proteins. PrOF NMR is first used to screen mixtures against two proteins. Hit mixtures for each protein are identified then deconvoluted using ¹H CPMG NMR. We demonstrate the benefit of this fragment screening method by conducting the first reported fragment screens against the bromodomains of BPTF and Plasmodium falciparum (Pf) GCN5 using 467 3D-enriched fragments. The hit rates were 6%, 5% and 4% for fragments binding BPTF, PfGCN5, and fragments binding both proteins, respectively. Select hits were characterized, revealing a broad range of affinities from low µM to mM dissociation constants. Follow-up experiments supported a low-affinity second binding site on PfGCN5. This approach can be used to bias fragment screens towards more selective hits at the onset of inhibitor development in a resource- and time-efficient manner.

The RNA Methyltransferase NSUN2 and Its Potential Roles in Cancer

5-methylcytosine is often associated as an epigenetic modifier in DNA. However, it is also found increasingly in a plethora of RNA species, predominantly transfer RNAs, but increasingly found in cytoplasmic and mitochondrial ribosomal RNAs, enhancer RNAs, and a number of long noncoding RNAs. Moreover, this modification can also be found in messenger RNAs and has led to an increasing appreciation that RNA methylation can functionally regulate gene expression and cellular activities. In mammalian cells, the addition of m5C to RNA cytosines is carried out by enzymes of the NOL1/NOP2/SUN domain (NSUN) family as well as the DNA methyltransferase homologue DNMT2. In this regard, NSUN2 is a critical RNA methyltransferase for adding m5C to mRNA. In this review, using non-small cell lung cancer and other cancers as primary examples, we discuss the recent developments in the known functions of this RNA methyltransferase and its potential critical role in cancer.

New inhibitors for the BPTF bromodomain enabled by structural biology and biophysical assay development

Bromodomain-containing proteins regulate transcription through protein-protein interactions with chromatin and serve as scaffolding proteins for recruiting essential members of the transcriptional machinery. One such protein is the bromodomain and PHD-containing transcription factor (BPTF), the largest member of the nucleosome remodeling complex, NURF. Despite an emerging role for BPTF in regulating a diverse set of cancers, small molecule development for inhibiting the BPTF bromodomain has been lacking. Here we cross-validate three complementary biophysical assays to further the discovery of BPTF bromodomain inhibitors for chemical probe development: two direct binding assays (protein-observed 19F (PrOF) NMR and surface plasmon resonance (SPR)) and a competitive inhibition assay (AlphaScreen). We first compare the assays using three small molecules and acetylated histone peptides with reported affinity for the BPTF bromodomain. Using SPR with both unlabeled and fluorinated BPTF, we further determine that there is a minimal effect of 19F incorporation on ligand binding for future PrOF NMR experiments. To guide medicinal chemistry efforts towards chemical probe development, we subsequently evaluate two new BPTF inhibitor scaffolds with our suite of biophysical assays and rank-order compound affinities which could not otherwise be determined by PrOF NMR. Finally, we cocrystallize a subset of small molecule inhibitors and present the first published small molecule-protein structures with the BPTF bromodomain. We envision the biophysical assays described here and the structural insights from the crystallography will guide researchers towards developing selective and potent BPTF bromodomain inhibitors.

Artificial intelligence-based collaborative filtering method with ensemble learning for personalized lung cancer medicine without genetic sequencing

In personalized medicine, many factors influence the choice of compounds. Hence, the selection of suitable medicine for patients with non-small-cell lung cancer (NSCLC) is expensive. To shorten the decision-making process for compounds, we propose a computationally efficient and cost-effective collaborative filtering method with ensemble learning. The ensemble learning is used to handle small-sample sizes in drug response datasets as the typical number of patients in a cancer dataset is very small. Moreover, the proposed method can be used to identify the most suitable compounds for patients without genetic data. To the best of our knowledge, this is the first method to provide effective recommendations without genetic data. We also constructed a reliable dataset that includes eight NSCLC cell lines and ten compounds that have been approved by the Food and Drug Administration. With the new dataset, the experimental results demonstrated that the dataset shift phenomenon that commonly occurs in practical biomedical data does not occur in this problem. The experimental results demonstrated that our proposed method can outperform two state-of-the-art recommender system techniques on both the NCI60 dataset and our new dataset. Our model can be applied to the prediction of drug sensitivity with less labor-intensive experiments in the future.

The Emerging Roles of ATP-Dependent Chromatin Remodeling Complexes in Pancreatic Cancer

Pancreatic cancer is an aggressive cancer with low survival rates. Genetic and epigenetic dysregulation has been associated with the initiation and progression of pancreatic tumors. Multiple studies have pointed to the involvement of aberrant chromatin modifications in driving tumor behavior. ATP-dependent chromatin remodeling complexes regulate chromatin structure and have critical roles in stem cell maintenance, development, and cancer. Frequent mutations and chromosomal aberrations in the genes associated with subunits of the ATP-dependent chromatin remodeling complexes have been detected in different cancer types. In this review, we summarize the current literature on the genomic alterations and mechanistic studies of the ATP-dependent chromatin remodeling complexes in pancreatic cancer. Our review is focused on the four main subfamilies: SWItch/sucrose non-fermentable (SWI/SNF), imitation SWI (ISWI), chromodomain-helicase DNA-binding protein (CHD), and INOsitol-requiring mutant 80 (INO80). Finally, we discuss potential novel treatment options that use small molecules to target these complexes.

SphK1 functions downstream of IGF-1 to modulate IGF-1-induced EMT, migration and paclitaxel resistance of A549 cells: A preliminary in vitro study

Insulin-like growth factor-1 (IGF-1) -induced epithelial-mesenchymal transition (EMT) plays a key role in the metastasis and drug resistance of non-small cell lung cancer (NSCLC). Sphingosine kinase-1 (SphK1) is also involved in EMT of NSCLC. However, the interaction between SphK1 and IGF-1 in the EMT of NSCLC is largely unknown. To clarify this issue, we examined the involvement of SphK1 in IGF-1-induced EMT using human lung cancer cell line A549, and its paclitaxel-resistant subline. Cell viability was evaluated by cell counting kit-8 assay; Migratory ability was examined using scratch wound healing test; Protein expression levels of SphK1, vimentin, fibronectin, N-cadherin and E-cadherin were detected by western blot analysis, respectively. The results showed that, IGF-1 treatment of A549 cells stimulated the expression of SphK1, the activation of ERK and AKT, the cell migration, and the expression of EMT hallmark proteins, while inhibition of SphK1 by its specific inhibitor SKI-II suppressed all the above changes and increased the sensitivity of A549 cells to paclitaxel. Our data demonstrate that SphK1 acts as a downstream effector of IGF-1 and plays a critical role in IGF-1-induced EMT, cell migration and paclitaxel resistance of A549 cells, suggesting that SphK1 might be a potential therapeutic target for NSCLC.