Promotes Cancer Cell Invasion Research Articles

SOX4 induces cytoskeleton remodeling and promotes cell motility via N-wasp/ARP2/3 pathway in colorectal cancer cells

Filopodia are thin, actin-rich projection from the plasma membrane that promote cancer cell invasion and migration. Sex-determining region Y-related high-mobility group-box 4 (SOX4) is a crucial transcription factor that plays a role in the development and metastasis of colorectal cancer (CRC). However, the involvement of SOX4 in cytoskeleton remodeling in CRC remains unknown. For the first time, we demonstrate that SOX4 is a potent regulator of filopodia formation in CRC cells. Overexpression of SOX4 protein enhances both migration and invasion ability of HCT116, and CACO2 cells, which is relevant to the metastasis. Furthermore, through phalloidin staining, cytoskeleton re-assembly was observed in SOX4-modified cell lines. Enhanced expression of SOX4 increased the number and length of filopodia on cell surface. In contrast, silencing SOX4 in SW620 cells with higher endogenous expression of SOX4, impeded the filopodia formation. Moreover, SOX4 was found to be positively regulating the expression of central regulators of actin cytoskeleton - N-Wiskott-Aldrich syndrome protein (N-WASP); WAVE2; Actin related proteins, ARP2 and ARP3. Inhibiting the N-WASP/ARP2/3 pathway diminishes the filopodia formation and the migration of CRC cells. These results indicate the crucial role of SOX4 in the regulation of filopodia formation mediated by N-WASP/ARP2/3 pathway in CRC cells.

Abstract 2900: BRAFi-induced epigenetic switch drives the reprogramming of resistant cancer-associated fibroblasts

Abstract Cancer-associated fibroblasts (CAFs) are a potential target for optimizing therapeutic strategies against melanoma. However, a major unknown still exists in CAFs, which is how CAFs maintain and even reinforce their functions in drug therapy and influence melanoma cell drug sensitivity. Yes-associated protein 1 (YAP1) is the master regulator that shuttles between the cytoplasm and nucleus in CAFs. Apparently, proteins associated with nuclear YAP1 in CAFs when treated with BRAF inhibitor (BRAFi) can potentially influence tumor drug response. Here we unveil that CAFs require the YAP1 function to proliferate, migrate, remodel the cytoskeletal machinery and matrix, and promote cancer cell invasion. Ablating YAP1 in CAFs increases the response of BRAF-mutant melanoma cells to BRAFi and MEK inhibitor (MEKi) in vivo and in vitro. Using an approach termed RIME (Rapid Immunoprecipitation Mass Spectrometry), we purified nuclear YAP1 and identified protein arginine methyl transferase 1 (PRMT1) as a major YAP1 binding partner in BRAFi-treated CAFs. Binding PRMT1 to YAP1 was confirmed by Co-immunoprecipitation and proximity ligation assay, and YAP1 deficiency in CAFs diminishes the nuclear accumulation of PRMT1, suggesting BRAFi-induced nuclear translocation of PRMT1 in CAFs requires the formation of YAP1 and PRMT1 complex. Silencing PRMT1 expression in CAFs not only deprives them of their ability to proliferate and to induce BRAF mutant melanoma cell resistance to BRAFi and MEKi. PRMT1 is a type I R-methyltransferase that mediates arginine methylation in human cells, which was known to be recruited to chromatin and exert its enzymatic activity to methylate Arg3 of histone H4 (H4R3). Using Histone H4 Modification Multiple Assay, we observed a global increase in Histone H4 methylation, especially H4R3 methylation, in CAFs in response to BRAFi stimulation, suggesting increased chromatin unfolding and accessibility and transcription activation. When YAP1 or PRMT1 expression was silenced, H4R3 methylation was notably suppressed, indicating BRAFi-induced H4R3 methylation was indeed driven by the YAP1 and PRMT1 signaling axis. In conclusion, our data disclose a novel BRAFi-induced YAP1-PRMT1-mediated epigenetic mechanism that reprograms CAFs through H4R3 methylation-directed transcriptional activation to reinforce their drug-resistant functions and modulate melanoma cell drug sensitivity. Moreover, the discovery of PRMT1 as a key player in the intricate molecular mechanisms that govern epigenetic regulation in CAFs in response to BRAFi treatment suggest PRMT1 as a potential CAF target in cancer therapy. Citation Format: Yao Xiao, Linli Zhou, Yuhang Zhang. BRAFi-induced epigenetic switch drives the reprogramming of resistant cancer-associated fibroblasts [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 2900.

Elevated extracellular matrix protein 1 in circulating extracellular vesicles supports breast cancer progression under obesity conditions

The cargo content in small extracellular vesicles (sEVs) changes under pathological conditions. Our data shows that in obesity, extracellular matrix protein 1 (ECM1) protein levels are significantly increased in circulating sEVs, which is dependent on integrin-β2. Knockdown of integrin-β2 does not affect cellular ECM1 protein levels but significantly reduces ECM1 protein levels in the sEVs released by these cells. In breast cancer (BC), overexpressing ECM1 increases matrix metalloproteinase 3 (MMP3) and S100A/B protein levels. Interestingly, sEVs purified from high-fat diet-induced obesity mice (D-sEVs) deliver more ECM1 protein to BC cells compared to sEVs from control diet-fed mice. Consequently, BC cells secrete more ECM1 protein, which promotes cancer cell invasion and migration. D-sEVs treatment also significantly enhances ECM1-mediated BC metastasis and growth in mouse models, as evidenced by the elevated tumor levels of MMP3 and S100A/B. Our study reveals a mechanism and suggests sEV-based strategies for treating obesity-associated BC.

Intercellular transfer of cancer cell invasiveness via endosome-mediated protease shedding

Overexpression of the transmembrane matrix metalloproteinase MT1-MMP/MMP14 promotes cancer cell invasion. Here we show that MT1-MMP-positive cancer cells turn MT1-MMP-negative cells invasive by transferring a soluble catalytic ectodomain of MT1-MMP. Surprisingly, this effect depends on the presence of TKS4 and TKS5 in the donor cell, adaptor proteins previously implicated in invadopodia formation. In endosomes of the donor cell, TKS4/5 promote ADAM-mediated cleavage of MT1-MMP by bridging the two proteases, and cleavage is stimulated by the low intraluminal pH of endosomes. The bridging depends on the PX domains of TKS4/5, which coincidently interact with the cytosolic tail of MT1-MMP and endosomal phosphatidylinositol 3-phosphate. MT1-MMP recruits TKS4/5 into multivesicular endosomes for their subsequent co-secretion in extracellular vesicles, together with the enzymatically active ectodomain. The shed ectodomain converts non-invasive recipient cells into an invasive phenotype. Thus, TKS4/5 promote intercellular transfer of cancer cell invasiveness by facilitating ADAM-mediated shedding of MT1-MMP in acidic endosomes.

Exploring the importance of kynurenine pathway (KP) approaches in colorectal cancer (CRC)

One of the main causes of cancer-related fatalities is colorectal cancer (CRC). The majority of patients frequently receive a late diagnosis of colorectal cancer (CRC) due to the absence of accurate prognostic and predictive biomarkers. Furthermore, greater metastasis and shorter survival rates were seen in colorectal cancer (CRC) patients. Recent advances in cancer treatment have been made possible by therapeutic immune system potentiation. The immune system and the kynurenine pathway (KP) are closely related. As a result of kynurenine's promotion of T Reg (regulatory) differentiation, more anti-inflammatory cytokines are produced and the cytotoxic activity of T cells is suppressed. In malignancies, the overactivation of the kynurenine pathway (KP) creates a micro environment where mutant cells can survive and invade neighboring tissues.The poor prognosis of several cancers, including gastrointestinal cancers, gynecological cancers, hematologic malignancies, breast cancer, lung cancer, glioma, melanoma, prostate cancer, and pancreatic cancer, is predicted by overactivation of the kynurenine pathway (KP), particularly the overactivation of indoleamine 2,3-dioxygenase (IDO). Additionally, kynurenine promotes cancer cell invasion, metastasis, and chemoresistance. The evolving understanding of the kynurenine pathway (KP) and its use in colorectal cancer (CRC) is covered in this review. An essential amino acid called tryptophan can be processed by several different pathways, with the kynurenine pathway (KP) being one of the more important ones. Kynurenine (KYN) is recognized as an oncometabolite in colon cancer, and colorectal cancer (CRC) that results from its subsequent metabolites. For several physiological activities, indoleamine 2,3-dioxygenase (IDO), a crucial enzyme that catalyzes kynurenine metabolism, is required. We talked about IDO's role in colorectal cancer (CRC) in this review. IDO knockdown decreased the expression of cancer stem cell markers as well as the ability of colorectal cancer (CRC) cells to migrate and invade. The application of an inhibitor to restrict the enzymatic activity of IDO also prevented the formation of spheres and hindered cell motility in colorectal cancer (CRC) cells. These findings demonstrate the clinical significance of IDO in the growth and tumorigenicity of colorectal cancer (CRC) tumors.

KCTD4 interacts with CLIC1 to disrupt calcium homeostasis and promote metastasis in esophageal cancer.

Increasing evidences suggest the important role of calcium homeostasis in hallmarks of cancer, but its function and regulatory network in metastasis remain unclear. A comprehensive investigation of key regulators in cancer metastasis is urgently needed. Transcriptome sequencing (RNA-seq) of primary esophageal squamous cell carcinoma (ESCC) and matched metastatic tissues and a series of gain/loss-of-function experiments identified potassium channel tetramerization domain containing 4 (KCTD4) as a driver of cancer metastasis. KCTD4 expression was found upregulated in metastatic ESCC. High KCTD4 expression is associated with poor prognosis in patients with ESCC and contributes to cancer metastasis invitro and invivo. Mechanistically, KCTD4 binds to CLIC1 and disrupts its dimerization, thus increasing intracellular Ca2+ level to enhance NFATc1-dependent fibronectin transcription. KCTD4-induced fibronectin secretion activates fibroblasts in a paracrine manner, which in turn promotes cancer cell invasion via MMP24 signaling as positive feedback. Furthermore, a lead compound K279-0738 significantly suppresses cancer metastasis by targeting the KCTD4‒CLIC1 interaction, providing a potential therapeutic strategy. Taken together, our study not only uncovers KCTD4 as a regulator of calcium homeostasis, but also reveals KCTD4/CLIC1-Ca2+-NFATc1-fibronectin signaling as a novel mechanism of cancer metastasis. These findings validate KCTD4 as a potential prognostic biomarker and therapeutic target for ESCC.

Identification of small molecules that suppress cell invasion and metastasis promoted by WASF3 activation

The WASF3 gene promotes cancer cell invasion and metastasis, and genetic inactivation leads to suppression of metastasis. To identify small molecules that might interfere with WASF3 function, we performed an in silico docking study to the regulatory pocket of WASF3 using the National Cancer Institute (NCI) diversity set VI small molecule library. Compounds that showed the maximum likelihood of interaction with WASF3 were screened for their effect on cell movement in breast and prostate cancer cells, a well-established predictor of invasion and metastasis. Three hit compounds were identified that affected cell movement, and the same compounds also suppressed cell migration and invasion in vitro in both MDA-MB-231 breast cancer cells and Du145 prostate cancer cells. Using a zebrafish metastasis assay, one of these compounds, NSC670283, showed significant suppression of metastasis in vivo while not affecting cell proliferation. NSC670283 showed a consistent effect on suppression of invasion and metastasis, and cellular temperature shift assays provided support for physical interaction with WASF3. In addition, suppression of cell movement and invasion was accompanied by a decrease in actin filament polymerization. The data in this study suggest that these small molecules inhibit cancer cell invasion and metastasis, and to our knowledge, it is the first identification of a small molecule that can potentially inhibit WASF3-directed metastasis, laying the foundation for medicinal chemistry approaches to enhance the potency of the identified compounds.

Matrix metalloproteinases and tissue inhibitors in multiple myeloma: promote or inhibit?

Matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) play a vital role in the pathogenesis of multiple myeloma (MM), especially for tumor invasion and osteolytic osteopathy. By breaking down extracellular matrix (ECM) components and releasing the proteins composing the ECM and growth factors, as well as their receptors, MMPs affect tissue integrity and promote cancer cell invasion and metastasis. A vital pathophysiological characteristic of MM is the progress of osteolytic lesions, which are brought on by interactions between myeloma cells and the bone marrow microenvironment. MMPs, certainly, are one of the fundamental causes of myeloma bone disease due to their ability to degrade various types of collagens. TIMPs, as important regulators of MMP hydrolysis or activation, also participate in the occurrence and evolution of MM and the formation of bone disease. This review focuses on the role of MMP-1, MMP-2, MMP-7, MMP-9, MMP-13, MMP-14, and MMP-15 and the four types of TIMPs in the invasion of myeloma cells, angiogenesis, osteolytic osteopathy, to offer some novel perspectives on the clinical diagnostics and therapeutics of MM.

Abstract PO-077: High-throughput 3D-spheroid invasion assay: A powerful tool to identify novel drugs targeting tumor micro-environment in HNSCC

Abstract Cancer metastasis is a complex cascade that involves activation of cancer cell invasion and migration. This activation is greatly attributed by multiple factors, including the tumor-microenvironment (TME). Cancer-associated fibroblasts (CAF), a prominent cell type within the TME, have been shown to promote cancer cell invasion and migration, causing metastasis in various cancers including head and neck squamous cell carcinoma (HNSCC). The molecular mechanisms of how CAFs promote HNSCC invasion remain elusive. Our research goal is to understand how CAFs influence HNSCC cells to become invasive and potentially metastatic. Using a top-down research approach, our aim is to identify novel therapeutic chemical probe/drug regimens that potentially target CAF-dependent HNSCC cancer cell-invasion. In-order to perform high-throughput small molecule screens, we have established a 384-well format, three-dimensional (3D) spheroid invasion assay, as a powerful tool to study CAF-dependent HNSCC cancer cell invasion. This platform is currently being used to screen small molecule libraries and identify putative molecular targets, providing insights into underlying mechanisms of CAF-induced cancer cell invasion and candidate therapeutic strategies. Citation Format: Kunal Karve, Stephanie Poon, Panagiotis Prinos, Laurie Ailles. High-throughput 3D-spheroid invasion assay: A powerful tool to identify novel drugs targeting tumor micro-environment in HNSCC [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-077.

ETV5 transcriptionally activates TGFβ1 and promotes cancer cell invasion and migration of NSCLC.

The morbidity and mortality of NSCLC remains high worldwide. However, the molecular mechanisms of NSCLC still largely unclear. Ets variant 5 (ETV5) is a transcription factor that found to be overexpressed in multiple cancers. However, the role of ETV5 in NSCLC remains unknown. We aim to explore the role and mechanisms of ETV5 in NSCLC development. The expression of ETV5 was evaluated in NSCLC tissues and cell lines. ETV5 overexpressing and downregulation cell lines were established according to the endogenous expression of ETV5. Functional studies were performed by transwell assay. The downstream targets of ETV5 were screened by PCR array and were confirmed by luciferase reporter assay. We found that overexpression of ETV5 indicates worse prognosis of NSCLC patients. Elevated ETV5 expression promotes NSCLC cell invasion and migration via transcriptional activates of TGFβ1. Therefore, ETV5/TGFβ signaling may serve as a therapeutic target for NSCLS patients.

SPRY4 as a Potential Mediator of the Anti-Tumoral Role of Macrophages in Anaplastic Thyroid Cancer Cells.

Anaplastic thyroid carcinoma (ATC) is the most lethal subtype of thyroid cancer, with high invasive and metastatic potential, not responding to conventional treatments. Its aggressiveness may be influenced by macrophages, which are abundant cells in the tumor microenvironment. To investigate the role of macrophages in ATC aggressiveness, indirect co-cultures were established between ATC cell lines and THP-1-derived macrophages. Macrophages significantly increased both the migration and invasion of T235 cells (p < 0.01; p < 0.01), contrasting with a decrease in C3948 (p < 0.001; p < 0.05), with mild effects in T238 migration (p < 0.01) and C643 invasion (p < 0.05). Flow cytometry showed upregulation of CD80 (pro-inflammatory, anti-tumoral) and downregulation of CD163 (anti-inflammatory, pro-tumoral) in macrophages from co-culture with T235 (p < 0.05) and C3948 (p < 0.05), respectively. Accordingly, we found an upregulation of secreted pro-inflammatory mediators (e.g., GM-CSF, IL-1α; p < 0.05) in C3948-macrophage co-cultures. Proteomic analysis showed the upregulation of SPRY4, an inhibitor of the MAPK pathway, in C3948 cells from co-culture. SPRY4 silencing promoted cancer cell invasion, reverting the reduced invasion of C3948 caused by macrophages. Our findings support that macrophages play a role in ATC cell aggressiveness. SPRY4 is a possible modulator of macrophage-ATC cell communication, with a tumor suppressor role relevant for therapeutic purposes.

A TGF-β-responsive enhancer regulates SRC expression and epithelial-mesenchymal transition-associated cell migration.

The non-receptor tyrosine kinase, SRC, is overexpressed and/or hyperactivated in various human cancers and facilitates cancer progression by promoting invasion and metastasis. However, the mechanisms underlying SRC upregulation are poorly understood. In this study, we demonstrated that transforming growth factor-β (TGF-β) induces SRC expression at the transcriptional level by activating an intragenic the SRC enhancer. In the human breast epithelial cell line MCF10A, TGF-β1 stimulation upregulated the SRC1A promoter, resulting in increased SRC mRNA and protein levels. Chromatin immunoprecipitation (ChIP)-sequencing analysis revealed that SMAD complex is recruited to three enhancer regions ∼15 kb upstream and downstream of the SRC promoter, and one of them is capable of activating the SRC promoter in response to TGF-β. JUN, a member of the activator protein (AP)-1 family, localises to the enhancer and regulates TGF-β-induced SRC expression. Furthermore, TGF-β-induced SRC upregulation plays a crucial role in epithelial-mesenchymal transition (EMT)-associated cell migration by activating the SRC/focal adhesion kinase (FAK) circuit. Overall, these results suggest that TGF-β-induced SRC upregulation promotes cancer cell invasion and metastasis in a subset of human malignancies.

An oncogenic isoform of septin 9 promotes the formation of juxtanuclear invadopodia by reducing nuclear deformability

Invadopodia are extracellular matrix (ECM) degrading structures, which promote cancer cell invasion. The nucleus is increasingly viewed as a mechanosensory organelle that determines migratory strategies. However, how the nucleus crosstalks with invadopodia is little known. Here, we report that the oncogenic septin 9 isoform 1 (SEPT9_i1) is a component of breast cancer invadopodia. SEPT9_i1 depletion diminishes invadopodium formation and the clustering of the invadopodium precursor components TKS5 and cortactin. This phenotype is characterized by deformed nuclei and nuclear envelopes with folds and grooves. We show that SEPT9_i1 localizes to the nuclear envelope and juxtanuclear invadopodia. Moreover, exogenous lamin A rescues nuclear morphology and juxtanuclear TKS5 clusters. Importantly, SEPT9_i1 is required for the amplification of juxtanuclear invadopodia, which is induced by the epidermal growth factor. We posit that nuclei of low deformability favor the formation of juxtanuclear invadopodia in a SEPT9_i1-dependent manner, which functions as a tunable mechanism for overcoming ECM impenetrability.

USP14 regulates heme metabolism and ovarian cancer invasion through BACH1 deubiquitination and stabilization

The deubiquitinating enzyme USP14 has been established as a crucial regulator in various diseases, including tumors, neurodegenerative diseases, and metabolic diseases, through its ability to stabilize its substrate proteins. Our group has utilized proteomic techniques to identify new potential substrate proteins for USP14, however, the underlying signaling pathways regulated by USP14 remain largely unknown. Here, we demonstrate the key role of USP14 in both heme metabolism and tumor invasion by stabilizing the protein BACH1. The cellular oxidative stress response factor NRF2 regulates antioxidant protein expression through binding to the antioxidant response element (ARE). BACH1 can compete with NRF2 for ARE binding, leading to the inhibition of the expression of antioxidant genes, including HMOX-1. Activated NRF2 also inhibits the degradation of BACH1, promoting cancer cell invasion and metastasis. Our findings showed a positive correlation between USP14 expression and NRF2 expression in various cancer tissues from the TCGA database and normal tissues from the GTEx database. Furthermore, activated NRF2 was found to increase USP14 expression in ovarian cancer (OV) cells. The overexpression of USP14 was observed to inhibit HMOX1 expression, while USP14 knockdown had the opposite effect, suggesting a role for USP14 in regulating heme metabolism. The depletion of BACH1 or inhibition of heme oxygenase 1 (coded by HMOX-1) was also found to significantly impair USP14-dependent OV cell invasion. In conclusion, our results highlight the importance of the NRF2-USP14-BACH1 axis in regulating OV cell invasion and heme metabolism, providing evidence for its potential as a therapeutic target in related diseases.

ITGB1BP1, a Novel Transcriptional Target of CD44-Downstream Signaling Promoting Cancer Cell Invasion.

Breast cancer (BC) is the most common malignancy worldwide and has a poor prognosis, because it begins in the breast and disseminates to lymph nodes and distant organs. While invading, BC cells acquire aggressive characteristics from the tumor microenvironment through several mechanisms. Thus, understanding the mechanisms underlying the process of BC cell invasion can pave the way towards the development of targeted therapeutics focused on metastasis. We have previously reported that the activation of CD44 receptor with its major ligand hyaluronan (HA) promotes BC metastasis to the liverin vivo. Next, a gene expression profiling microarray analysis was conducted to identify and validate CD44-downstream transcriptional targets mediating its pro-metastatic function from RNA samples collected from Tet CD44-inducedversuscontrol MCF7-B5 cells. We have already validated a number of novel CD44-target genes and published their underlying signaling pathways in promoting BC cell invasion. From the same microarray analysis, Integrin subunit beta 1 binding protein 1 (ITGB1BP1) was also identified as a potential CD44-target gene that was upregulated (2-fold) upon HA activation of CD44. This report will review the lines of evidence collected from the literature to support our hypothesis, and further discuss the possible mechanisms linking HA activation of CD44 to its novel potential transcriptional target ITGB1BP1.

PRAME Is a Novel Target of Tumor-Intrinsic Gas6/Axl Activation and Promotes Cancer Cell Invasion in Hepatocellular Carcinoma.

(1) Background: Activation of the receptor tyrosine kinase Axl by Gas6 fosters oncogenic effects in hepatocellular carcinoma (HCC), associating with increased mortality of patients. The impact of Gas6/Axl signaling on the induction of individual target genes in HCC and its consequences is an open issue. (2) Methods: RNA-seq analysis of Gas6-stimulated Axl-proficient or Axl-deficient HCC cells was used to identify Gas6/Axl targets. Gain- and loss-of-function studies as well as proteomics were employed to characterize the role of PRAME (preferentially expressed antigen in melanoma). Expression of Axl/PRAME was assessed in publicly available HCC patient datasets and in 133 HCC cases. (3) Results: Exploitation of well-characterized HCC models expressing Axl or devoid of Axl allowed the identification of target genes including PRAME. Intervention with Axl signaling or MAPK/ERK1/2 resulted in reduced PRAME expression. PRAME levels were associated with a mesenchymal-like phenotype augmenting 2D cell migration and 3D cell invasion. Interactions with pro-oncogenic proteins such as CCAR1 suggested further tumor-promoting functions of PRAME in HCC. Moreover, PRAME showed elevated expression in Axl-stratified HCC patients, which correlates with vascular invasion and lowered patient survival. (4) Conclusions: PRAME is a bona fide target of Gas6/Axl/ERK signaling linked to EMT and cancer cell invasion in HCC.

CSF-1R promotes vasculogenic mimicry via epithelial-mesenchymal transition in nasopharyngeal carcinoma cells

Abstract Objectives In nasopharyngeal carcinoma (NPC), the main factors for treatment failure are local recurrence and metastasis. Vasculogenic mimicry (VM), formation by invasive cancer cells mimicking the vasculogenic network, is strongly correlated with tumor therapy resistance and distant metastasis. CSF-1R was substantially expressed in NPC patients with a poor prognosis, according to an earlier study of ours. However, whether CSF-1R affects progression through vasculogenic mimicry deserves consideration. Methods By cultivating NPC cells that had CSF-1R overexpression in three-dimensional culture and labeling the NPC xenografts with CD34-PAS vasculogenic mimicry markers, the effect of CSF-1R on VM formation, migration, and invasion of NPC cells was evaluated. Finally, the underlying mechanisms were investigated by western blot. Results In vitro and in vivo, overexpressing CSF-1R in NPC cells causes the development of vessel-like structures. Meanwhile, NPC cells migrated and invaded more readily in the Transwell experiment when CSF-1R was highly expressed. Mechanistically, our research indicates that CSF-1R may control cell plasticity by activating the PI3K/AKT signaling pathway, promoting the formation of VM in these cells by facilitating the epithelial-mesenchymal transition. Conclusions CSF-1R in NPC progression by increasing VM production to increase nutrient supply to tumor cells and promote cancer cell invasion. Furthermore, these findings suggest that CSF-1R is a new promising therapeutic target aimed at treating VM in NPC.

Abstract 5843: miR-224 activates cancer-associated fibroblasts to promote cancer cell invasion in lung tumor microenvironment

Abstract Cancer-associated fibroblasts (CAFs) promote EMT (epithelial-mesenchymal transition), invasion, and metastasis of cancer cells in the tumor microenvironment. To identify microRNAs (miRNAs) associated with the reprogramming of normal lung fibroblasts (LFs) into CAFs, global miRNA expression was profiled in LFs and CAFs through Nanostring nCounter. miR-224 was one of the increased miRNAs in CAFs, and its expression was higher in tumors than in normal tissues in dbDEMC and TCGA_lung adenocarcinoma data. miR-224 levels were then checked by qRT-PCR in paraffine-embedded tumor samples from patients with lung adenocarcinoma. Kaplan-Meier survival analysis showed that high miR-224 expression was related to poor survival. These data show that lung cancer progression is promoted by miR-224. To discover the roles of increased miR-224 in CAFs, miR-224 was overexpressed by lentiviral infection in LFs. LF_miR-224 overexpression enhanced the expression of CAF activation markers including Fap, S100a4, and Vim. In spheroid invasion assay using co-culture of LFs and cancer cells, as an experimental model of the tumor microenvironment, LF_miR-224 promoted invasion of lung cancer cells compared with control LFs. In transwell migration assay, LF_miR-224 stimulated migration of lung cancer cells more than control LFs. Collectively, these results indicate that CAFs reprogrammed by miR-224 promote the migration and invasion of lung cancer cells. Citation Format: Seonyeong Oh, Inyoung Cheon, Young-Ho Ahn. miR-224 activates cancer-associated fibroblasts to promote cancer cell invasion in lung tumor microenvironment. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5843.

Abstract 2489: Study the efficacy of hypomethylating agent in treating regular and brain metastasized HER2-positive breast cancer

Abstract Breast cancer is the second leading cause of cancer with the highest mortality rate in females in the United States. Late stage breast cancer can metastasize to different locations of the body, and patients with brain metastasis have a poor prognosis and short survival time. HER2-positive breast cancer, composed of ~15-20% of total cases, is aggressive with unfavorable clinical outcomes. Although HER2-targeted therapies are available, they are mostly ineffective against brain metastasis. To study tumor metastasis, we had established the breast cancer brain metastasis preclinical cell and mouse models. Our previous study has shown that the hypomethylating agent azacitidine (AZA) is effective in treating brain metastasis triple-negative breast cancer using in vitro cell and in vivo mouse models. Thus, we hypothesized that AZA will be effective to treat HER2-positive breast cancer. To test our hypothesis, we treated regular (JIMT-1) and brain metastasized (JIMT-1 Br) HER2-positive breast cancer cell lines with various concentrations of AZA, and the IC50 values, cell proliferation, and apoptosis were measured. Our results showed that train metastasized HER2-positive breast cancer JIMT-1 Br cells have similar growth rate compared to their parental regular breast cancer JIMT-1 cells. Regular breast cancer cells are more sensitive to AZA treatment, supported by (1) The IC50 value of AZA in JIMT-1 cells is significantly lower than that in JIMT-1 Br cells; (2) 72 hours of AZA treatment significantly inhibited cell grow in both cell lines, and the inhibition of JIMT-1 growth is greater than that of JIMT-1 Br cells; (3) AZA triggered apoptosis in both cell lines in a dose-dependent manner; (4) Higher concentrations of AZA induced a higher percentage of cell apoptosis in JIMT-1 compared to JIMT-1 Br cells. AZA treatment does not significantly change the expression of metastasis protein markers in either cell line. Epithelial-mesenchymal transition promotes cancer cell invasion and metastasis. Epithelial markers include cytokeratins and E-cadherin, and mesenchymal markers include N-cadherin and vimentin. We measured the expression of those markers in both cell lines after AZA treatment by Western blotting, and found that the expression of pan-cytokeratins and keratin 18 were equivalent between both cell lines upon AZA treatment. However, the expression of keratin 19, E-cadherin, N-cadherin, and vimentin were not detected in either cell line. In conclusion, in this study, we tested the in vitro effects of the hypomethylating agent AZA in both regular and brain metastasized HER2-positive breast cancer cells. We found that AZA inhibits cell growth and promotes apoptosis in both cell types, but the regular breast cancer cells are more sensitive to AZA treatment compared to brain metastasized cells, shown by the differences in IC50 values and extents of cell growth inhibition and apoptosis induction. Citation Format: Tuoen Liu, Christopher Butler, Kelsey Donoughe, Lauren Forchette, William Sebastian, Gabor Szalai, Paul Lockman. Study the efficacy of hypomethylating agent in treating regular and brain metastasized HER2-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2489.

Abstract 3136: HYENA detects non-coding genes activated by distal enhancers in cancer

Abstract Genome instability is a hallmark of cancer, resulting in the accumulation of mutation. Among different types of mutations, structural variants (SVs) widely spread in cancer genomes and can be important cancer drivers, demonstrated in multiple cancer types. SVs can induce oncogene activation by redirecting enhancers to promoter regions or disrupting chromatin topology. These events are called “enhancer hijacking” and known to upregulate oncogenes in multiple cancers. Enhancers are among the best understood cis-regulatory elements and are essential regulators for precise gene expression in normal tissue. Since SV associated gene deregulation has been shown in multiple cancer types, it is a feasible way to infer putative oncogenes by detecting enhancer hijacking events. Taking advantage of next generation sequencing, bioinformatic tools were developed to study pan-histology protein-coding gene deregulation caused by SVs. However, algorithms that can unbiasedly detect enhancer hijacking in both coding and non-coding genes are yet to be developed. Here we present a computational algorithm “HYENA” to identify putative oncogenes activated by enhancer hijacking using whole-genome sequencing and RNA sequencing data. It deploys rank-based regression model to test whether an SV breakpoint located close to a gene significantly increases the gene expression. Permutation tests were used to generate a false discovery rate for each gene. By benchmarking with existing tools serving similar purposes, we confirmed that HYENA has superior capabilities to infer enhancer hijacking events. We detected 192 oncogene candidates in 1,148 tumor samples from 25 cancer types. While confirming the known cases of enhancer hijacking, we also identified numerous novel oncogene candidates, of which a substantial proportion was non-coding genes. Specifically, we found that a long non-coding RNA TOB1-AS1 was activated by rearranged enhancers in 10% of pancreatic cancer samples. Furthermore, experimental validation with pancreatic cancer cell lines and immunodeficient mice indicated that high expression of TOB1-AS1 is capable to promote cancer cell invasion and tumor metastasis, suggesting it is a novel cancer driver. As the existing treatments for pancreatic cancer are largely inefficacious and patients still have poor prognosis, new targets are urgently needed to improve pancreatic cancer treatments. Although the molecular mechanisms underlying TOB1-AS1 promoted metastasis remain to be unveiled, this non-coding gene can be a promising target in the patients carrying this enhancer hijacking event. In summary, our results demonstrated that HYENA is a sensitive and reliable tool to infer enhancer hijacking activated oncogenes and spot new potential targets to treat cancer. Citation Format: Anqi Yu, Ali E. Yesilkanal, Ashish Thakur, Fan Wang, Xiaoyang Wu, Alexander Muir, Xin He, Francois Spitz, Lixing Yang. HYENA detects non-coding genes activated by distal enhancers in cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3136.