Tumor Cell EMT Research Articles

Retraction Note: Micafungin exerts antitumor effect on breast cancer and osteosarcoma through preventing EMT in tumor cells in an USP7/AKT/GSK-3β pathway-dependent manner.

Retraction Note: Micafungin exerts antitumor effect on breast cancer and osteosarcoma through preventing EMT in tumor cells in an USP7/AKT/GSK-3β pathway-dependent manner.

Orosomucoid 2 upregulation mediates liver injury-induced colorectal cancer liver metastasis by promoting EMT and cell migration.

The relationship between drug-induced liver injury and liver metastasis of colorectal cancer and the underlying mechanisms are not well understood. In this study, we used carbon tetrachloride to construct a classic mouse liver injury model and injected CT26 colorectal cancer cells into the mouse spleen to simulate the natural route of colorectal cancer liver metastasis. Liver injury significantly increased the number of colorectal cancer liver metastases. Transcriptome sequencing and data-independent acquisition protein quantification identified proteins that were significantly differentially expressed in injured livers, and orosomucoid (ORM) 2 was identified as a target protein for tumor liver metastasis. Invitro experiments showed that exogenous ORM2 protein increased the expression of EMT markers such as Twist, Zeb1, Vim, Snail1 and Snail2 and chemokine ligands to promote CT26 cell migration. In addition, liver-specific overexpression of the ORM2 protein in the mouse model significantly promoted tumor cell liver metastasis without inducing liver injury. Our results indicate that drug-induced liver injury can promote colorectal cancer liver metastasis and that ORM2 can promote cell migration by inducing EMT in tumor cells.

H3K18 lactylation-mediated VCAM1 expression promotes gastric cancer progression and metastasis via AKT-mTOR-CXCL1 axis

The role of the Immunoglobulin Superfamily (IgSF) as adhesion molecules in orchestrating inflammation is pivotal, yet its specific involvement in gastric cancer (GC) remains unknown. We analyzed IgSF components and discerned conspicuously elevated VCAM1 expression in GC, correlating with a poor prognosis. Remarkably, VCAM1 enhances GC cell proliferation and migration by activating AKT-mTOR signaling. Moreover, lactate in the tumor microenvironment (TME) promotes dynamic lactylation of H3K18 (H3K18la), leading to transcriptional activation of VCAM1 in GC cells. Furthermore, VCAM1 actively mediates intercellular communication in the TME. AKT-mTOR-mediated CXCL1 expression is increased by VCAM1, facilitating the recruitment of human GC-derived mesenchymal stem cells (hGC-MSCs), thereby fostering immunesuppression and accelerating cancer progression. In summary, H3K18 lactylation upregulated VCAM1 transcription, which activated AKT-mTOR signaling, and promoted tumor cell proliferation, EMT Transition and tumor metastasis. VCAM1 upregulated CXCL1 expression by AKT-mTOR pathway, so as to facilitate hGC-MSCs and M2 macrophage recruitment and infiltration. These findings provide novel therapeutic targets for GC.

The stromal microenvironment endows pancreatic neuroendocrine tumors with spatially specific invasive and metastatic phenotypes

Cancer-associated fibroblasts (CAFs) play an important role in a variety of cancers. However, the role of tumor stroma in nonfunctional pancreatic neuroendocrine tumors (NF-PanNETs) is often neglected. Profiling the heterogeneity of CAFs can reveal the causes of malignant phenotypes in NF-PanNETs. Here, we found that patients with high stromal proportion had poor prognosis, especially for that with infiltrating stroma (stroma and tumor cells that presented an infiltrative growth pattern and no regular boundary). In addition, myofibroblastic CAFs (myCAFs), characterized by FAP+ and α-SMAhigh, were spatially closer to tumor cells and promoted the EMT and tumor growth. Intriguingly, only tumor cells which were spatially closer to myCAFs underwent EMT. We further elucidated that myCAFs stimulate TGF-β expression in nearby tumor cells. Then, TGF-β promoted the EMT in adjacent tumor cells and promoted the expression of myCAFs marker genes in tumor cells, resulting in distant metastasis. Our results indicate that myCAFs cause spatial heterogeneity of EMT, which accounts for liver metastasis of NF-PanNETs. The findings of this study might provide possible targets for the prevention of liver metastasis.

Hsa_circ_0009092/miR-665/NLK signaling axis suppresses colorectal cancer progression via recruiting TAMs in the tumor microenvironment

BackgroundIt has been demonstrated that circularRNA (circRNAs) plays a critical role in various cancers. While the potential molecular mechanism of circRNAs in the progression of colorectal cancer (CRC) remains uncertain.MethodsDifferentially expressed circRNAs were identified by RNA sequencing. RT-qPCR detected the expression of circ_0009092, miR-665, and NLK in CRC tissues and cells. Functions of circ_0009092 on tumor cell proliferation, migration, and invasion were investigated by a series of in vitro assays. The underlying mechanism of circ_0009092 was explored by bioinformatics analysis, RNA immunoprecipitation (RIP) and luciferase assays. A co-culture assay in vitro was performed to detect the affection of circ_0009092 on macrophage recruitment in the tumor microenvironment (TME). A xenograft mouse model was used to explore the effect of circ_0009092 on tumor growth.ResultsCirc_0009092 was downregulated in CRCand predicted a good prognosis. Overexpression of circ_0009092 reduced tumor cell EMT, proliferation, migration, and invasion in vitro and in vivo. Mechanistically, circ_0009092 elevated the NLK expression via sponging miR-665 and suppressed the Wnt/β-catenin signaling pathway. EIF4EA3 induced circ_0009092 expression in CRC cells. In addition, NLK regulates phosphorylation and O-GlcNAcylation of STAT3 by binding to STAT3, thereby inhibiting CCL2 expression, in which it inhibits macrophage recruitment in the tumor microenvironment (TME).ConclusionEIF4A3 suppressed circ_0009092 biogenesis, whichinhibits CRC progression by sponging miR-665 to downregulate NLK. Circ_0009092/miR-665/NLK suppressed tumor EMT, proliferation, migration, and invasion by acting on the Wnt/β-catenin signaling pathway. NLK directly interacted with STAT3 and decreased the CCL2 expression, inhibiting the recruitment of tumor-associated macrophages (TAMs) in the TME. Our study provided novel insights into the roles of circ_0009092 as a novel promising prognostic and therapeutic target in CRC.

MiR-625 Inhibits Tumor Cell Invasion, Migration and EMT by Negatively Regulating the Expression of Resistin in Non-Small Cell Lung [Retraction

[This retracts the article DOI: 10.2147/CMAR.S248251.].

An updated review of contribution of long noncoding RNA-NEAT1 to the progression of human cancers.

Long non-coding RNAs (lncRNAs) present pivotal roles in cancer tumorigenesis and progression. Recently, nuclear paraspeckle assembly transcript 1 (NEAT1) as a lncRNA has been shown to mediate cell proliferation, migration, and EMT in tumor cells. NEAT1 by targeting several miRNAs/mRNA axes could regulate cancer cell behavior. Therefore, NEAT1 may function as a potent biomarker for the prediction and treatment of some human cancers. In this review, we summarized various NEAT1-related signaling pathways that are critical in cancer initiation and progression.

Exosome-transmitted circIFNGR2 Modulates Ovarian Cancer Metastasis via miR-378/ST5 Axis.

Cancer-associated fibroblasts (CAFs)-derived exosomes have emerged as a key driver of ovarian cancer (OVCA) tumor progression. The mechanisms behind the specific circular RNA (circRNA) activity encapsulated by CAF-generated exosomes (CAF-exo) requires to be elucidated. Herein, this study selected specific circRNA (hsa_circIFNGR2) molecules and aimed to clarify novel function of CAF-derived exosomal circIFNGR2 on growth, and metastasis of OVCA cells. In this study, we clarified that the exosomes of CAFs originating from human ovarian cancer hindered tumor cell proliferation, metastasis and EMT invitro. Interestingly, CAFs directly transferred exosomes into OVCA cells to enrich intracellular circIFNGR2 levels. Biologically, activation of exosomal circIFNGR2 blocked cell proliferation, metastasis and EMT. Mechanistically, enhanced circIFNGR2 activated the miR-378/ST5 axis and directly inhibited the malignant evolution of tumor cells. Furthermore, rescue experiments evidenced that circIFNGR2 and ST5 were two essential participants in OVCA, concretely manifested in the co-culture of OVCA cells with exosomes that reversed the effects of intracellular circIFNGR2 and ST5 depletion. Finally, we observed that CAF-exo treatment hindered tumor growth and increased the size and number of metastatic nodules in mice. Our study revealed a previously unknown regulatory pathway whereby CAFs-derived exosomes delivered circIFNGR2 and inhibited the malignant progression of OVCA by circIFNGR2/miR-378/ST5 axis.

Abstract B020: Reprogramming epithelial-mesenchymal transition and the immune microenvironment in triple-negative breast cancer with epigenetic drugs

Abstract Triple-negative breast cancer (TNBC) is a biologically heterogeneous and clinically important breast cancer subtype because if considered a distinct disease, TNBC would rank as the 5th leading cause of cancer deaths in women. Patients resistant to standard-of-care chemotherapies have poor survival. EMT is a reversible process in which epithelial cells lose polarity and cell-cell junctions to gain mesenchymal traits. A hybrid EMT state that displays plasticity is correlated with chemotherapy resistance. Besides tumor intrinsic factors, tumor-associated immune cells such as neutrophils and macrophages can display a pro-tumoral phenotype and contribute to chemotherapy resistance. Epigenetic enzymes can reprogram both the tumor cell EMT and tumor-associated immune cells. Thus, targeting epigenetic enzymes is a potential strategy to improve the response of TNBC to chemotherapy. Our overall goal, therefore, is to identify novel epigenetic drug(s) that can potentially be used in the clinic in combination with chemotherapy to improve the survival of TNBC patients. Previously, we performed a morphology-based epigenetic drug screen using organoid cultures of two independent mesenchymal TNBC cell models. We identified ten epigenetic drugs able to reprogram EMT, specifically several histone deacetylase (HDAC) and bromodomain (BRD) inhibitors. We selected Quisinostat, an HDAC inhibitor, and IACS-70654, an inhibitor of p300/CBP BRD, as representative of these two classes of drugs for further study. First, we determined the effects of both inhibitors in our unique syngeneic TNBC mouse models. In a claudin-low mesenchymal model T12, IACS-70654 induced the expression of epithelial marker ZO-1, reduced tumor proliferation, and reduced the infiltration of neutrophils. Accordingly, we then treated a neutrophil-enriched luminal-like TNBC model 2208L with IACS-70654. We discovered that IACS-70654 prevented tumor growth and drastically decreased neutrophil infiltration. Quisinostat also reduced tumor proliferation, improved the response to Carboplatin, and strongly induced the expression of epithelial marker E-cadherin in the T12 model. Moreover, it reduced neutrophil and regulatory T cell infiltration significantly and increased anti-tumoral macrophage infiltration. To complement these in vivo studies, we also isolated tumor-associated macrophages from T12 and studied their response in vitro to assess the direct effects of the inhibitors. Both epigenetic drugs reduced the expression of the pro-tumoral phenotype markers Arginase 1 and CD206 and induced the expression of the anti-tumoral phenotypic markers CD86 and MHCII. In summary, we showed that both Quisinostat and IACS-70654 reduced tumor proliferation and reprogramed both tumor cell EMT and tumor-associated immune cells. Future studies will characterize the effects of both compounds in additional TNBC models and employ single-cell ATAC-seq and RNA-seq to elucidate potential mechanisms and pathways employed by these two different classes of epigenetic drugs in both tumor cells and tumor-associated immune cells. Citation Format: Xueying Yuan, Michael Soth, Philip Jones, Jeffrey Rosen. Reprogramming epithelial-mesenchymal transition and the immune microenvironment in triple-negative breast cancer with epigenetic drugs. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B020.

The Role of RKIP in the Regulation of EMT in the Tumor Microenvironment

Simple SummaryRaf kinase inhibitor protein (RKIP) expression in cancer cells is significantly reduced and promoting cancer cells growth and invasiveness. Overexpresssion of RKIP has been reported to mediate pleiotropic anti-cancer activities including the inhibition of survival signaling pathways, sensitization to cell death by cytotoxic drugs, inhibition of invasion, EMT and metastasis. The molecular mechanism by which RKIP inhibits EMT is not clear. In this review, we have examined how RKIP inhibits the selected EMT gene products (Snail, vimentin, N-cadherin, laminin alpha) and found that it involves signaling cross-talks between RKIP and each of the EMT gene products. These findings were validated by bioinformatic analyses demonstrating in various human cancers a negative correlation between the expression of RKIP and the expression of the EMT gene products. These findings suggest that targeting RKIP induction in cancer cells will result in multiple hits by inhibiting tumor growth, metastasis and reversal of chemo-immuno resistance.The Raf Kinase Inhibitor Protein (RKIP) is a unique gene product that directly inhibits the Raf/Mek/Erk and NF-kB pathways in cancer cells and resulting in the inhibition of cell proliferation, viability, EMT, and metastasis. Additionally, RKIP is involved in the regulation of cancer cell resistance to both chemotherapy and immunotherapy. The low expression of RKIP expression in many cancer types is responsible, in part, for the pathogenesis of cancer and its multiple properties. The inhibition of EMT and metastasis by RKIP led to its classification as a tumor suppressor. However, the mechanism by which RKIP mediates its inhibitory effects on EMT and metastases was not clear. We have proposed that one mechanism involves the negative regulation by RKIP of the expression of various gene products that mediate the mesenchymal phenotype as well as the positive regulation of gene products that mediate the epithelial phenotype via signaling cross talks between RKIP and each gene product. We examined several EMT mesenchymal gene products such as Snail, vimentin, N-cadherin, laminin and EPCAM and epithelial gene products such as E-cadherin and laminin. We have found that indeed these negative and positive correlations were detected in the signaling cross-talks. In addition, we have also examined bioinformatic data sets on different human cancers and the findings corroborated, in large part, the findings observed in the signaling cross-talks with few exceptions in some cancer types. The overall findings support the underlying mechanism by which the tumor suppressor RKIP regulates the expression of gene products involved in EMT and metastasis. Hence, the development of agent that can selectively induce RKIP expression in cancers with low expressions should result in the activation of the pleiotropic anti-cancer activities of RKIP and resulting in multiple effects including inhibition of tumor cell proliferation, EMT, metastasis and sensitization of resistant tumor cells to respond to both chemotherapeutics and immunotherapeutics.

Abstract 1572: FZD6 and RYK, non-canonical Wnt receptors in pancreatic cancer progression

Abstract Pancreatic ductal adenocarcinoma (PDAC) has a grim prognosis with 5-year patient survival of less than 10%. Development of effective therapeutics has been hampered by the PDAC tumor microenvironment (TME), which contains dense desmoplastic stroma that likely impedes the ability of therapies to reach the tumor cells. We have found that aggressive, “basal-like” human PDAC tumors have high expression of proteins involved in planar-cell-polarity (PCP), a type of non-canonical Wnt signaling. We show that the increased expression of the PCP genes, including the putative non-canonical Wnt ligand, Wnt5a, the Frizzled 6 (FZD6) Wnt receptor, and RYK co-receptor negatively impact patient prognosis. Using a panel of FZD6 knock-down pancreatic cell lines, we show that loss of FZD6 increases expression of the epithelial marker, E-cadherin, and decreases cellular motility in Transwell assays. We also find that loss of Fzd6 dramatically inhibits tumor progression in two mouse models of PDAC, with a pronounced change to the TME; including the cancer-associated fibroblasts (CAFs) and immune cells. Blinded histologic pathology review of tumor and immune cell infiltrates, by H&E and alphaSMA staining, suggests that the CAF cell population is altered. We propose this is the cause of the looser stroma surrounding the tumors after Fzd6 loss, which also results in an increased abundance of CD4 and CD8 positive T cells surrounding and within the tumors. Additionally, immunohistochemical staining for other PCP proteins within the pancreatic tumors lacking Fzd6 suggests that Fzd6 loss reduces PCP-component protein levels. We hypothesize that the loss of Fzd6 reduces tumor cell EMT and PCP signaling, while the loose stroma allows more immune cells that further slow tumor growth and progression. We have also examined the expression of PCP proteins in a novel orthotopic xenotransplantation model of PDAC, intraductally grafted organoids (IGO). IGO is a powerful tool to study PDAC as the intraductal tumors that develop recapitulate patient to patient heterogeneity while displaying features of either classical or basal-like PDAC subtypes. FZD6 and RYK are both more highly expressed in the IGO basal-like tumors than the classical type. Introduction of fast-growing, basal-like human tumors into the murine pancreas also resulted in a TME that produces more Wnt5a, when compared to the stroma surrounding tumors formed by injecting the classical subtype. Taken together, we believe we have identified a Wnt5a/Fzd6 driven PCP-like signaling pathway that makes tumors more mesenchymal-like, and results in PDAC tumor progression and worse patient prognosis. Citation Format: Payton D. Stevens, Emily Sall, Alex Zhong, Galen Hostetter, Zachary Madaj, Jennifer Thalappillil, Alexander Dobin, Youngkyu Park, David A. Tuveson, Bart O. Williams. FZD6 and RYK, non-canonical Wnt receptors in pancreatic cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1572.

DLX6-AS1: A Long Non-coding RNA With Oncogenic Features.

Long non-coding RNAs (lncRNAs) are a heterogeneous group of ncRNAs with characteristic size of more than 200 nucleotides. An increasing number of lncRNAs have been found to be dysregulated in many human diseases particularly cancer. However, their role in carcinogenesis is not precisely understood. DLX6-AS1 is an lncRNAs which has been unveiled to be up-regulated in various number of cancers. In different cell studies, DLX6-AS1 has shown oncogenic role via promoting oncogenic phenotype of cancer cell lines. Increase in tumor cell proliferation, migration, invasion, and EMT while suppressing apoptosis in cancer cells are the effects of DLX6-AS1 in development and progression of cancer. In the majority of cell experiment, mediator miRNAs have been identified which are sponged and negatively regulated by DLX6-AS1, and they in turn regulate expression of a number of transcription factors, eventually affecting signaling pathways involved in carcinogenesis. These pathways form axes through which DLX6-AS1 promotes carcinogenicity of cancer cells. Xenograft animal studies, also have confirmed enhancing effect of DLX6-AS1 on tumor growth and metastasis. Clinical evaluations in cancerous patients have also shown increased expression of DLX6-AS1 in tumor tissues compared to healthy tissues. High DLX6-AS1 expression has shown positive association with advanced clinicopathological features in cancerous patients. Survival analyses have demonstrated correlation between high DLX6-AS1 expression and shorter survival. In cox regression analysis, DLX6-AS1 has been found as an independent prognostic factor for patients with various types of cancer.

MiR-20a-5p Negatively Regulates NR4A3 to Promote Metastasis in Bladder Cancer.

Metastasis is the leading cause of death in cancer patients. Therefore, the prediction and treatment of metastasis are critical in improving the survival of patients with bladder cancer. In this study, we aimed to investigate the role of miR-20a-5p and NR4A3 in bladder cancer and the regulatory relationship between them. The high expression of miR-20a-5p in the bladder cancer (BCa) tissues and cells was determined by qRT-PCR. Exogenous miR-20a-5p overexpression promoted the proliferation, migration, and invasion of BCa cells. MiR-20a-5p inhibition inhibited the BCa cell proliferation, invasion, and migration. NR4A3 was proved to be the target gene of miR-20a-5p by the double luciferase reporter assay. In addition, the reduction of NR4A3 could promote the proliferation, invasion, and clonal formation of the bladder cancer cells 5637 and T24. NR4A3 overexpression could reverse the carcinogenic effect of miR-20a. We further confirmed that the oncogenic effect of miR-20a was achieved by promoting EMT in tumor cells. MiR-20a-5p promoted the growth and metastasis of the bladder cancer cells by inhibiting the expression of the tumor suppressor gene NR4A3 and played a carcinogenic role in BCa. Thus, miR-20a-5p may become a potential therapeutic target for BCa treatment.

High level of TXNDC9 predicts poor prognosis and contributes to the NF-κB-regulated metastatic potential in gastric cancer.

Gastric cancer (GC) is the most frequent malignant tumor in the digestive system, with high metastasis potential and poor prognosis. This study aimed to investigate the prognostic value and biological function of thioredoxin domain-containing protein 9 (TXNDC9) in GC. The expression of TXNDC9 was analyzed based on The Cancer Genome Atlas (TCGA) database. The prognostic value of TXNDC9 was evaluated by Kaplan-Meier curves and Cox regression analysis. The mRNA and protein expression of TXNDC9 were analyzed using quantitative real-time PCR and western blot analysis. The effects of TXNDC9 on GC cell invasion and EMT were assessed in vitro, and its effects on tumorigenesis were confirmed using animal experiments. The activity of the NF-κB signaling pathway was examined by both in vitro and in vivo experiments. TXNDC9 was highly expressed in GC tissues and cell lines. A high level of TXNDC9 was associated with poor overall survival and served as an independent prognostic biomarker in GC patients. The knockdown of TXNDC9 led to restrained GC cell invasion, microtubule formation, and EMT in vitro, and suppressed tumorigenesis in vivo. In addition, the NF-κB signaling pathway was demonstrated to mediate the functional role of TXNDC9 in GC. In conclusion, this study found that high TXNDC9 predicted poor prognosis in GC, and served as an oncogene by enhancing tumor cell invasion and EMT through the NF-κB signaling pathway.

Qingjie Fuzheng Granule Inhibits EMT and Induces Autophagy in Colorectal Cancer via mTOR Signaling Pathways.

Qingjie Fuzheng granule (QFG) is a traditional Chinese medicinal formula used extensively as an alternative medicine for cancer treatment, including colorectal cancer (CRC). But its pathological mechanism in CRC is unclear. To study antitumor treatment effects and mechanisms of QFG, we established a CRC HCT-116 xenograft mouse model and assessed QFG on EMT and autophagy progression in vivo. The mice were randomly divided into 2 groups (n = 10 each group) and treated with intragastric administration of 1 g/kg of QFG or saline 6 days a week for 28 days (4 weeks). Body weight was measured every other day with electronic balance. At the end of the treatment, the tumor weight was measured. Immunohistochemical (IHC) and western blot (WB) assay were used to detect the expression level of E-cadherin, N-cadherin, vimentin, and TWIST1 to evaluate the effect of QFG on tumor cell EMT progression. IHC and WB assay were also used to detect the expression level of beclin-1, LC3-II, and p62 to evaluate the effect of QFG on tumor cell autophagy progression. Furthermore, the expression level of relative proteins in mTOR pathway was detected by WB assay to investigate the mechanism of QFG effect on CRC. We discovered that QFG inhibited the rise of tumor weight while it had no effect on mice body weight, which proved that QFG could inhibit CRC growth progression without significant side effects in vivo. In addition, QFG treatment inhibited EMT and induced autophagy progression in CRC tumor cells, including that QFG upregulated the expression of E-cadherin, beclin-1, and LC3-II, but downregulated the expression of N-cadherin, vimentin, TWIST1, and p62. And, QFG decreased the ratio of p-PI3K/PI3K, p-AKT/AKT, and p-mTOR/mTOR, but increased the ratio of p-AMPK/AMPK. All findings from this research proved that QFG can induce autophagy and inhibit EMT progression in CRC via regulating the mTOR signaling pathway.

MRPL13 Promotes Tumor Cell Proliferation, Migration and EMT Process in Breast Cancer Through the PI3K-AKT-mTOR Pathway.

PurposeBreast cancer (BC), with varying histopathology, biology and response to systemic treatment, is the second leading cause of cancer-related mortality. Previous studies have inferred that the expression of mitochondrial ribosomal proteins (MRPs) is possibly related to the occurrence/progression of BC. MRPL13 might be one of the potential MRP candidates that are involved in BC tumorigenesis, but its role in BC has rarely been reported. The purpose of the current study was to evaluate the prognostic significance of MRPL13, as well as to explore its potential biological functions in BC.Materials and MethodsA series of bioinformatic and statistical methods were adopted to assess the MRPL13 expression profile, its relationship with clinicopathological characteristics, copy number variation (CNV), impact on clinical outcomes and relevant functions. All the results are analysed by 1097 BC patients collected from The Cancer Genome Atlas (TCGA) dataset and 52 clinical samples for immunohistochemistry (IHC) assay.ResultsThe results demonstrated that the expression of MRPL13 in BC tissues was remarkably elevated than that in normal breast tissues. In addition, the Kaplan-Meier curves and Cox model indicated that patients with high MRPL13 expression were connected to a worse prognosis, heralding the independent prognostic value of this protein in BC. Moreover, an enrichment analysis showed that MRPL13 was mainly involved in cell cycle/division-related, RNA processing (degradation/splicing), MYC targets and the MTORC1 pathways. In addition, RNA interference (RNAi)-mediated MRPL13 silencing remarkedly inhibited proliferation and migration as well as the expression of EMT-related genes of BC cells in vitro. Mechanistically, attenuation of MRPL13 significantly suppressed the phosphorylation of AKT and mTOR, which could be partially abolished by 740Y-P (a PI3K agonist).ConclusionOur results provide evidence for the first time that increased MRPL13 expression correlates with adverse clinicopathological variables and unfavorable clinical outcomes of BC patients. Knockdown of MRPL13 restrains the proliferation and migration potential and EMT process of BC through inhibiting PI3K/AKT/mTOR signaling pathway.

Abstract 1966: Obesity and prostate cancer progression: Role of the chemokine CXCL12

Abstract Obesity is a significant risk factor for several cancers in both men and women. A number of studies have shown that obesity is associated with increased prostate cancer (PCa) progression and higher mortality. However, the mechanism(s) for obesity-driven PCa remain unclear. In earlier studies, we showed that obesity enhances PCa progression in the HiMyc mouse model by changing the surrounding tumor microenvironment, especially the white adipose tissue (WAT). WAT consists of many cells including inflammatory cells, mature adipocytes and adipose stromal cells (ASCs). Here, we further investigated the role of ASCs and ASC derived CXCL12 in obesity-driven PCa progression. In HMVP2 cells, a PCa cell line derived from HiMyc mice expressing high levels of CXCR4, we observed activation of MAPKs (JNK and ERK), AKT, STAT3 and NFkB following treatment with CXCL12. These CXCL12-induced signaling pathways were inhibited by treating with AMD3100, a CXCR4 antagonist, and also by CXCR4 knock-down. To confirm this in vivo, we compared PCa tumor growth in lean and obese mice using the HMVP2 allograft model. Our data demonstrates that obesity promotes EMT in tumor cells and increases invasion of surrounding WAT into the tumor stoma. Treatment of mice with AMD3100 significantly inhibited the growth of HMVP2 tumors and suppressed EMT in both the obese and control diet groups. Furthermore, D-CAN, a hunter-killer peptide developed for targeting ASCs, also suppressed obesity-induced EMT and tumor growth in HMVP2 tumor allografts. Lastly, AMD3100 in combination with D-CAN, showed a significant reduction in PCa growth in obese mice compared to either agent used alone. These results provide evidence that ASCs activate the CXCL12/CXCR4 signaling as well as other pathways playing an important role in obesity-driven PCa progression. Our data suggests this pathway as a novel therapeutic target for inhibiting obesity-driven PCa growth and progression. Research supported by NCI Grant CA196259. Citation Format: Songyeon Ahn, Achinto Saha, Mikhail G. Kolonin, John DiGiovanni. Obesity and prostate cancer progression: Role of the chemokine CXCL12 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1966.

Collective cell migration and metastases induced by an epithelial-to-mesenchymal transition in Drosophila intestinal tumors

Metastasis underlies the majority of cancer-related deaths yet remains poorly understood due, in part, to the lack of models in vivo. Here we show that expression of the EMT master inducer Snail in primary adult Drosophila intestinal tumors leads to the dissemination of tumor cells and formation of macrometastases. Snail drives an EMT in tumor cells, which, although retaining some epithelial markers, subsequently break through the basal lamina of the midgut, undergo a collective migration and seed polyclonal metastases. While metastases re-epithelialize over time, we found that early metastases are remarkably mesenchymal, discarding the requirement for a mesenchymal-to-epithelial transition for early stages of metastatic growth. Our results demonstrate the formation of metastases in adult flies, and identify a key role for partial-EMTs in driving it. This model opens the door to investigate the basic mechanisms underlying metastasis, in a powerful in vivo system suited for rapid genetic and drug screens.

The Epigenetic Factor KDM2B Regulates EMT and Small GTPases in Colon Tumor Cells

Background/Aims: The epigenetic factor KDM2B is a histone demethylase expressed in various tumors. Recently, we have shown that KDM2B regulates actin cytoskeleton organization, small Rho GTPases signaling, cell-cell adhesion and migration of prostate tumor cells. In the present study, we addressed its role in regulating EMT and small GTPases expression in colon tumor cells. Methods: We used RT-PCR for the transcriptional analysis of various genes, Western blotting for the assessment of protein expression and immunofluorescence microscopy for visualization of fluorescently labeled proteins. Results: We report here that KDM2B regulates EZH2 and BMI1 in HCT116 colon tumor cells. Knockdown of this epigenetic factor induced potent up-regulation of the protein levels of the epithelial markers E-cadherin and ZO-1, while the mesenchymal marker N-cadherin was downregulated. On the other hand, KDM2B overexpression downregulated the levels of both epithelial markers and upregulated the mesenchymal marker, suggesting control of EMT by KDM2B. In addition, RhoA, RhoB and RhoC protein levels diminished upon KDM2B-knockdown, while all three small GTPases became upregulated in KDM2B-overexpressing HCT116 cell clones. Interestingly, Rac1 GTPase level increased upon KDM2B-knockdown and diminished in KDM2B-overexpressing HCT116 colon tumor- and DU-145 prostate cancer cells. Conclusions: These results establish a clear functional role of the epigenetic factor KDM2B in the regulation of EMT and small-GTPases expression in colon tumor cells and further support the recently postulated oncogenic role of this histone demethylase in various tumors.

PM2.5 exposure-induced autophagy is mediated by lncRNA loc146880 which also promotes the migration and invasion of lung cancer cells

BackgroundEvidence shows that individuals who are under long-term exposure to environmental PM2.5 are at increased risk of lung cancer. Various laboratory experiments also suggest several mechanistic links between PM2.5 exposure and lung carcinogenesis. However, a long non-coding RNA (lncRNA) mediated pathogenic change after PM2.5 exposure and its potential roles in tumorigenesis and disease progression have not been reported. MethodsCytotoxicity induced by PM2.5 was assessed by using scanning electron microscopy and transmission electron microscopy. ROS generation, autophagy, and metastasis induced by PM2.5 were detected by using comprehensive approaches. Expression of lncRNA-loc146880 and lc3b (autophagy marker) in A549 cells, lung tissue and serum were determined by RT-PCR and Western blotting. ResultsPM2.5 could be internalized into lung cancer cells, resulting in marked increases in ROS levels and autophagy. ROS may be responsible for increased expression of loc146880 which further up-regulates autophagy. Both loc146880 and autophagy could promote lung tumor cell migration, invasion and EMT. In addition, a positive correlation was observed between loc146880 expression and lc3b levels in tumor tissues and serum of lung cancer patients. ConclusionTaken together, our data suggest that PM2.5 exposure induces ROS, which activates loc146880 expression. The lncRNA, in turn, up-regulates autophagy and promotes the malignant behaviors of lung cancer cells. General significanceThe results show the toxicological effects of PM2.5 in lung tumor progression and metastasis.