Bidirectional epithelial–mesenchymal crosstalk provides self-sustaining profibrotic signals in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the prototypic progressive fibrotic lung disease with a median survival of 2 to 4 years. Injury to and/or dysfunction of the alveolar epithelium is strongly implicated in IPF disease initiation, but the factors that determine whether fibrosis progresses rather than normal tissue repair occurs remain poorly understood. We previously demonstrated that zinc finger E-box-binding homeobox 1–mediated epithelial–mesenchymal transition in human alveolar epithelial type II (ATII) cells augments transforming growth factor-β–induced profibrogenic responses in underlying lung fibroblasts via paracrine signaling. Here, we investigated bidirectional epithelial–mesenchymal crosstalk and its potential to drive fibrosis progression. RNA-Seq of lung fibroblasts exposed to conditioned media from ATII cells undergoing RAS-induced epithelial–mesenchymal transition identified many differentially expressed genes including those involved in cell migration and extracellular matrix regulation. We confirmed that paracrine signaling between RAS-activated ATII cells and fibroblasts augmented fibroblast recruitment and demonstrated that this involved a zinc finger E-box-binding homeobox 1–tissue plasminogen activator axis. In a reciprocal fashion, paracrine signaling from transforming growth factor-β–activated lung fibroblasts or IPF fibroblasts induced RAS activation in ATII cells, at least partially through the secreted protein acidic and rich in cysteine, which may signal via the epithelial growth factor receptor via epithelial growth factor–like repeats. Together, these data identify that aberrant bidirectional epithelial–mesenchymal crosstalk in IPF drives a chronic feedback loop that maintains a wound-healing phenotype and provides self-sustaining profibrotic signals.     

DNAJB9 suppresses the metastasis of triple-negative breast cancer by promoting FBXO45-mediated degradation of ZEB1

DNAJB9, a member of the heat shock protein 40 family, acts as a multifunctional player involved in the maintenance of their client proteins and cellular homeostasis. However, the mechanistic action of DNAJB9 in human malignancies is yet to be fully understood. In this study, we found that ectopic restoration of DNAJB9 inhibits the migration, invasion, in vivo metastasis, and lung colonization of triple-negative breast cancer (TNBC) cells. Mechanistically, DNAJB9 stabilizes FBXO45 protein by suppressing self-ubiquitination and reduces the abundance of ZEB1 by Lys48-linked polyubiquitination to inhibit the epithelial–mesenchymal transition (EMT) and metastasis. Clinically, the reduction of DNAJB9 expression, concomitant with decreased FBXO45 abundance in breast cancer tissues, correlates with poorer clinical outcomes of patients with breast cancer. Taken together, our results provide a novel insight into the metastasis of TNBC and define a promising therapeutic strategy for cancers with overactive ZEB1 by regulating the DNAJB9–FBXO45 signaling axis.Subject terms: Breast cancer, Metastasis, Ubiquitylation, Tumour-suppressor proteins     

Prostasin regulates PD-L1 expression in human lung cancer cells

The serine protease prostasin is a negative regulator of lipopolysaccharide-induced inflammation and has a role in the regulation of cellular immunity. Prostasin expression in cancer cells inhibits migration and metastasis, and reduces epithelial–mesenchymal transition. Programmed death-ligand 1 (PD-L1) is a negative regulator of the immune response and its expression in cancer cells interferes with immune surveillance. The aim of the present study was to investigate if prostasin regulates PD-L1 expression. We established sublines overexpressing various forms of prostasin as well as a subline deficient for the prostasin gene from the Calu-3 human lung cancer cells. We report here that PD-L1 expression induced by interferon-γ (IFNγ) is further enhanced in cells overexpressing the wildtype membrane-anchored prostasin. The PD-L1 protein was localized on the cell surface and released into the culture medium in extracellular vesicles (EVs) with the protease-active prostasin. The epidermal growth factor-epidermal growth factor receptor (EGF-EGFR), protein kinase C (PKC), and mitogen-activated protein kinase (MAPK) participated in the prostasin-mediated up-regulation of PD-L1 expression. A Gene Set Enrichment Analysis (GSEA) of patient lung tumors in The Cancer Genome Atlas (TCGA) database revealed that prostasin and PD-L1 regulate common signaling pathways during tumorigenesis and tumor progression.     

Autophagic secretion of HMGB1 from cancer-associated fibroblasts promotes metastatic potential of non-small cell lung cancer cells via NFκB signaling

Tumor progression requires the communication between tumor cells and tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are major components of stromal cells. CAFs contribute to metastasis process through direct or indirect interaction with tumor cells; however, the underlying mechanism is largely unknown. Here, we reported that autophagy was upregulated in lung cancer-associated CAFs compared to normal fibroblasts (NFs), and autophagy was responsible for the promoting effect of CAFs on non-small cell lung cancer (NSCLC) cell migration and invasion. Inhibition of CAFs autophagy attenuated their regulation on epithelial–mesenchymal transition (EMT) and metastasis-related genes of NSCLC cells. High mobility group box 1 (HMGB1) secreted by CAFs mediated CAFs’ effect on lung cancer cell invasion, demonstrated by using recombinant HMGB1, HMGB1 neutralizing antibody, and HMGB1 inhibitor glycyrrhizin (GA). Importantly, the autophagy blockade of CAFs revealed that HMGB1 release was dependent on autophagy. We also found HMGB1 was responsible, at least in part, for autophagy activation of CAFs, suggesting CAFs remain active through an autocrine HMGB1 loop. Further study demonstrated that HMGB1 facilitated lung cancer cell invasion by activating the NFκB pathway. In a mouse xenograft model, the autophagy specific inhibitor chloroquine abolished the stimulating effect of CAFs on tumor growth. These results elucidated an oncogenic function for secretory autophagy in lung cancer-associated CAFs that promotes metastasis potential, and suggested HMGB1 as a novel therapeutic target.Subject terms: Cancer microenvironment, Non-small-cell lung cancer, Metastasis, Translational research     

Hsp70 acts as a fine-switch that controls E3 ligase CHIP-mediated TAp63 and ΔNp63 ubiquitination and degradation

The major clinical problem in human cancer is metastasis. Metastases are the cause of 90% of human cancer deaths. TAp63 is a critical suppressor of tumorigenesis and metastasis. ΔNp63 acts as a dominant-negative inhibitor to block the function of p53 and TAp63. Although several ubiquitin E3 ligases have been reported to regulate p63 stability, the mechanism of p63 regulation remains partially understood. Herein, we show that CHIP, an E3 ligase with a U-box domain, physically interacts with p63 and promotes p63 degradation. Notably, Hsp70 depletion by siRNA stabilizes TAp63 in H1299 cells and destabilizes ΔNp63 in SCC9 cells. Loss of Hsp70 results in a reduction in the TAp63-CHIP interaction in H1299 cells and an increase in the interaction between ΔNp63 and CHIP in SCC9 cells. Our results reveal that Hsp70 acts as a molecular switch to control CHIP-mediated ubiquitination and degradation of p63 isoforms. Furthermore, regulation of p63 by the Hsp70-CHIP axis contributes to the migration and invasion of tumor cells. Hence, our findings demonstrate that Hsp70 is a crucial regulator of CHIP-mediated ubiquitination and degradation of p63 isoforms and identify a new pathway for maintaining TAp63 or ΔNp63 stability in cancers.     

Linc00426 accelerates lung adenocarcinoma progression by regulating miR-455-5p as a molecular sponge

Increasing lines of evidence indicate the role of long non-coding RNAs (LncRNAs) in gene regulation and tumor development. Hence, it is important to elucidate the mechanisms of LncRNAs underlying the proliferation, metastasis, and invasion of lung adenocarcinoma (LUAD). We employed microarrays to screen LncRNAs in LUAD tissues with and without lymph node metastasis and revealed their effects on LUAD. Among them, Linc00426 was selected for further exploration in its expression, the biological significance, and the underlying molecular mechanisms. Linc00426 exhibits ectopic expression in LUAD tissues and cells. The ectopic expression has been clinically linked to tumor size, lymphatic metastasis, and tumor differentiation of patients with LUAD. The deregulation of Linc00426 contributes to a notable impairment in proliferation, invasion, metastasis, and epithelial–mesenchymal transition (EMT) in vitro and in vivo. Mechanistically, the deregulation of Linc00426 could reduce cytoskeleton rearrangement and matrix metalloproteinase expression. Meanwhile, decreasing the level of Linc00426 or increasing miR-455-5p could down-regulate the level of UBE2V1. Thus, Linc00426 may act as a competing endogenous RNA (ceRNA) to abate miR-455-5p-dependent UBE2V1 reduction. We conclude that Linc00426 accelerates LUAD progression by acting as a molecular sponge to regulate miR-455-5p, and may be a potential novel tumor marker for LUAD.Subject terms: Prognostic markers, Tumour biomarkers     

MMP-7 is Upregulated by COX-2 and Promotes Proliferation and Invasion of Lung Adenocarcinoma Cells

Matrix metalloproteinases (MMPs) have been implicated in a variety of pathophysiological conditions, of which MMP-7 is expressed by tumor cells of epithelial and mesenchymal origin. However, the function of MMP-7 in human lung adenocarcinoma (LAC) is unclear. In the present study the expression of MMP-7 in LAC was examined by immunohistochemical assay using a tissue microarray procedure. A loss-of-function experiment was performed to explore the effects and molecular mechanisms of lentiviral vector-mediated MMP-7 siRNA (siMMP-7) on cell proliferation and invasive potential in LAC A549 cells, measured by MTT and Transwell assays, respectively. It was found that, the expression of MMP-7 protein in LAC was significantly increased compared with that in adjacent non-cancerous tissues (ANCT) (76.0% vs 44.0%, P<0.001), and positively correlated with lymph node metastases of the tumor (P=0.014). Furthermore, targeted inhibition of cyclooxygenase-2 (COX-2) by siRNA downregulated the expression of MMP-7 and inhibited invasion of LAC cells, and knockdown of MMP-7 suppressed tumor proliferation and invasion in LAC cells. Taken together, our findings indicate that increased expression of MMP-7 is associated with lymph node metastasis and upregulated by COX-2, and promotes the tumorigenesis of LAC, suggesting that MMP-7 may be a potential therapeutic target for the treatment of cancer.Key words: MMP-7, COX-2, lung adenocarcinoma     

CircTMTC1 contributes to nasopharyngeal carcinoma progression through targeting miR-495-MET-eIF4G1 translational regulation axis

Nasopharyngeal carcinoma (NPC) is the most common primary malignancy arising from the epithelial cells of nasopharynx. CircTMTC1 is upregulated in NPC patients, but its role and molecular mechanism in NPC are unknown. Normal nasopharyngeal epithelium and tumor tissues were collected. The expression of circTMTC1, miR-495, MET/eIF4G1 pathway-related molecules were examined. Colony formation and transwell assays were used to assess cell proliferation, migration, and invasion. Cell apoptosis was analyzed by annexin V and propidium iodide (PI) staining. Gene interaction was examined by RNA immunoprecipitation (RIP) and luciferase activity assays. Subcutaneous and intravenous xenograft mouse models were established to analyze NPC growth and metastasis in vivo. CircTMTC1 was highly expressed and miR-495 was downregulated in NPC, which were associated with poor prognosis of NPC. Both circTMTC1 knockdown and miR-495 overexpression inhibited NPC cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) and promoted cell apoptosis. CircTMTC1 directly targeted miR-495 to promote the expression of its downstream target gene MET. miR-495 knockdown enhanced the expression of c-Myc, Cyclin D1, and survivin and accelerated NPC cell proliferation, migration, invasion, and EMT through targeting MET and activating the MET-eIF4G1 axis. CircTMTC1 silence inhibited NPC growth and lung metastasis by targeting the miR-495-MET-eIF4G1 translational regulation axis in vivo. CircTMTC1 accelerates NPC progression through targeting miR-495 and consequently activating the MET-eIF4G1 translational regulation axis, suggesting potential therapeutic targets for NPC treatment.Subject terms: Cancer, Diseases     

SIRT3 deficiency increases mitochondrial oxidative stress and promotes migration of retinal pigment epithelial cells

Retinal pigment epithelial cells are closely associated with the pathogenesis of diabetic retinopathy. The mechanism by which diabetes impacts retinal pigment epithelial cell function is of significant interest. Sirtuins are an important class of proteins that primarily possess nicotinamide adenine dinucleotide-dependent deacetylases activity and involved in various cellular physiological and pathological processes. Here, we aimed to examine the role of sirtuins in the induction of diabetes-associated retinal pigment epithelial cell dysfunction. High glucose and platelet-derived growth factor (PDGF) treatment induced epithelial–mesenchymal transition and the migration of retinal pigment epithelial cells, and decreased sirtuin-3 expression. Sirtuin-3 knockdown using siRNA increased epithelial–mesenchymal transition and migration of retinal pigment epithelial cells. In contrast, sirtuin-3 overexpression attenuated the effects caused by high glucose and PDGF on epithelial–mesenchymal transition and migration of retinal pigment epithelial cells, suggesting that sirtuin-3 deficiency contributed to retinal pigment epithelial cell dysfunction induced by high glucose and PDGF. Mechanistically, sirtuin-3 deficiency induced retinal pigment epithelial cell dysfunction by the overproduction of mitochondrial reactive oxygen species. These results suggest that sirtuin-3 deficiency mediates the migration of retinal pigment epithelial cells, at least partially by increasing mitochondrial oxidative stress, and shed light on the importance of sirtuin-3 and mitochondrial reactive oxygen species as potential targets in diabetic retinopathy therapy.     

Exosomal miR-146a-5p and miR-155-5p promote CXCL12/CXCR7-induced metastasis of colorectal cancer by crosstalk with cancer-associated fibroblasts

C-X-C motif chemokine receptor 7 (CXCR7) is a newly discovered atypical chemokine receptor that binds to C-X-C motif chemokine ligand 12 (CXCL12) with higher affinity than CXCR4 and is associated with the metastasis of colorectal cancer (CRC). Cancer-associated fibroblasts (CAFs) have been known to promote tumor progression. However, whether CAFs are involved in CXCR7-mediated metastasis of CRC remains elusive. We found a significant positive correlation between CXCR7 expression and CAF activation markers in colonic tissues from clinical specimens and in villin-CXCR7 transgenic mice. RNA sequencing revealed a coordinated increase in the levels of miR-146a-5p and miR-155-5p in CXCR7-overexpressing CRC cells and their exosomes. Importantly, these CRC cell-derived miR-146a-5p and miR-155-5p could be uptaken by CAFs via exosomes and promote the activation of CAFs through JAK2–STAT3/NF-κB signaling by targeting suppressor of cytokine signaling 1 (SOCS1) and zinc finger and BTB domain containing 2 (ZBTB2). Reciprocally, activated CAFs further potently enhanced the invasive capacity of CRC cells. Mechanistically, CAFs transfected with miR-146a-5p and miR-155-5p exhibited a robust increase in the levels of inflammatory cytokines interleukin-6, tumor necrosis factor-α, transforming growth factor-β, and CXCL12, which trigger the epithelial–mesenchymal transition and pro-metastatic switch of CRC cells. More importantly, the activation of CAFs by miR-146a-5p and miR-155-5p facilitated tumor formation and lung metastasis of CRC in vivo using tumor xenograft models. Our work provides novel insights into CXCR7-mediated CRC metastasis from tumor–stroma interaction and serum exosomal miR-146a-5p and miR-155-5p could serve as potential biomarkers and therapeutic targets for inhibiting CRC metastasis.Subject terms: Cancer microenvironment, Colon cancer     

Calcium signaling induces a partial EMT

Epithelial plasticity, or epithelial‐to‐mesenchymal transition (EMT), is a well‐recognized form of cellular plasticity, which endows tumor cells with invasive properties and alters their sensitivity to various agents, thus representing a major challenge to cancer therapy. It is increasingly accepted that carcinoma cells exist along a continuum of hybrid epithelial–mesenchymal (E‐M) states and that cells exhibiting such partial EMT (P‐EMT) states have greater metastatic competence than those characterized by either extreme (E or M). We described recently a P‐EMT program operating in vivo by which carcinoma cells lose their epithelial state through post‐translational programs. Here, we investigate the underlying mechanisms and report that prolonged calcium signaling induces a P‐EMT characterized by the internalization of membrane‐associated E‐cadherin (ECAD) and other epithelial proteins as well as an increase in cellular migration and invasion. Signaling through Gαq‐associated G‐protein‐coupled receptors (GPCRs) recapitulates these effects, which operate through the downstream activation of calmodulin‐Camk2b signaling. These results implicate calcium signaling as a trigger for the acquisition of hybrid/partial epithelial–mesenchymal states in carcinoma cells.     

CT45A1 acts as a new proto-oncogene to trigger tumorigenesis and cancer metastasis

Cancer/testis antigen (CTA)-45 family (CT45) belongs to a new family of genes in phylogenetics and is absent in normal tissues except for testis, but is aberrantly overexpressed in various cancer types. Whether CT45 and other CTAs act as proto-oncogenes has not been determined. Using breast cancer as a model, we found that CT45A1, a representative CT45 family member, alone had a weak tumorigenic effect. However, its neoplastic potency was greatly enhanced in the presence of growth factors. Overexpression of CT45A1 in breast cancer cells markedly upregulated various oncogenic and metastatic genes, constitutively activated ERK and CREB signaling pathways, promoted epithelial–mesenchymal transition, and increased cell stemness, tumorigenesis, invasion, and metastasis, whereas silencing CT45A1 significantly reduced cancer cell migration and invasion. We propose that CT45A1 functions as a novel proto-oncogene to trigger oncogenesis and metastasis. CT45A1 and other CT45 members are therefore excellent targets for anticancer drug discovery and targeted tumor therapy, and valuable genes in the study of a molecular phylogenetic tree.     

MicroRNA-93 Promotes Epithelial–Mesenchymal Transition of Endometrial Carcinoma Cells

MicroRNA-93, derived from a paralog (miR-106b-25) of the miR-17-92 cluster, is involved in the tumorigenesis and progression of many cancers such as breast, colorectal, hepatocellular, lung, ovarian, and pancreatic cancer. However, the role of miR-93 in endometrial carcinoma and the potential molecular mechanisms involved remain unknown. Our results showed that miR-93 was overexpressed in endometrial carcinoma tissues than normal endometrial tissues. The endometrial carcinoma cell lines HEC-1B and Ishikawa were transfected with miR-93-5P, after which cell migration and invasion ability and the expression of relevant molecules were detected. MiR-93 overexpression promoted cell migration and invasion, and downregulated E-cadherin expression while increasing N-cadherin expression. Dual-luciferase reporter assay showed that miR-93 may directly bind to the 3′ untranslated region of forkhead box A1 (FOXA1); furthermore, miR-93 overexpression downregulated FOXA1 expression while miR-93 inhibitor transfection upregulated FOXA1 expression at both mRNA and protein level. In addition, transfection with the most effective FOXA1 small interfering RNA promoted both endometrial cancer cell migration and invasion, and downregulated E-cadherin expression while upregulating N-cadherin expression. Therefore, we suggest that miR-93 may promote the process of epithelial–mesenchymal transition in endometrial carcinoma cells by targeting FOXA1.     

Laminin α1 Chain Synthesis in the Mouse Developing Lung: Requirement for Epithelial–Mesenchymal Contact and Possible Role in Bronchial Smooth muscle Development

Laminins, the main components of basement membranes, are heterotrimers consisting of α, β, and γ polypeptide chains linked together by disulfide bonds. Laminins-1 and -2 are both composed of β1 and γ1 chains and differ from each other on their α chain, which is α1 and α2 for laminin-1 and -2, respectively. The present study shows that whereas laminins-1 and -2 are synthesized in the mouse developing lung and in epithelial–mesenchymal cocultures derived from it, epithelial and mesenchymal monocultures lose their ability to synthesize the laminin α1 chain. Synthesis of laminin α1 chain however returns upon re-establishment of epithelial–mesenchymal contact. Cell–cell contact is critical, since laminin α1 chain is not detected in monocultures exposed to coculture-conditioned medium or in epithelial–mesenchymal cocultures in which heterotypic cell–cell contact is prevented by an interposing filter. Immunohistochemical studies on cocultures treated with brefeldin A, an inhibitor of protein secretion, indicated both epithelial and mesenchymal cells synthesize laminin α1 chain upon heterotypic cell– cell contact. In a set of functional studies, embryonic lung explants were cultured in the presence of monoclonal antibodies to laminin α1, α2, and β/γ chains. Lung explants exposed to monoclonal antibodies to laminin α1 chain exhibited alterations in peribronchial cell shape and decreased smooth muscle development, as indicated by low levels of smooth muscle α actin and desmin. Taken together, our studies suggest that laminin α1 chain synthesis is regulated by epithelial–mesenchymal interaction and may play a role in airway smooth muscle development.     

A novel circular RNA,hsa-circ-0000211, promotes lung adenocarcinoma migration and invasion through sponging of hsa-miR-622 and modulating HIF1-α expression

Recently, several studies have evaluated the role of circular RNAs in the metastasis and development of multiple cancers. In our earlier microarray-based study, we had reported the aberrant expression of a novel circular RNA, hsa-circ-0000211 in lung adenocarcinoma (LAC) tissues. However, the roles of hsa-circ-0000211 in LAC have not been studied. Here hsa-circ-0000211 expression in the LAC tissues and cell lines was determined by quantitative real-time PCR (qRT-PCR). The function of hsa-circ-0000211 was evaluated by transwell assay and wound healing. Mechanisms of hsa-circ-0000211 was measured by luciferase reporter assay and western blot. Results revealed the expression of hsa-circ-0000211 in the human LAC tissues and LAC cell lines was higher than that in normal tissue and human lung normal epithelial cells, respectively. The knockdown of hsa-circ-0000211 could inhibit the migration and invasion properties of LAC. Furthermore, hsa-circ-0000211 promoted the migration and invasion of LAC by sponging miR-622. Moreover, hsa-circ-0000211 upregulated the HIF1-α expression by targeting miR-622. hsa-circ-0000211 promoted LAC cell migration and invasion by modulating the miR-622/HIF1-α network. Our study demonstrated that hsa-circ-0000211 can be a potential novel therapeutic target for LAC.     

miR-375 Mediated Acquired Chemo-Resistance in Cervical Cancer by Facilitating EMT

Acquired chemo-resistance is one of the key causal factors in cancer death. Emerging evidences suggest that miRNA and epithelial–mesenchymal transition play critical roles in the chemo-resistance in cancers. Here, we showed the association of paclitaxel-resistance with miR-375 over-expression and epithelial–mesenchymal transition inducement in cervical cancer. Using different cervical cancer cell models, we found that paclitaxel transiently induced up-regulation of miR-375 expression, proliferation inhibition, transition from epithelial to mesenchymal phenotype, and consequently impaired paclitaxel sensitivity. Forced over-expression of miR-375 may suppress Ecadherin expression by a directly targeting pathway, which led to paclitaxel resistance. Contrarily, re-expression of Ecadherin partly reversed epithelial–mesenchymal transition phenotype and miR-375 induced paclitaxel-resistance. Our findings suggest that paclitaxel-induced miR-375 over-expression facilitates epithelial–mesenchymal transition process via directly targeting Ecadherin, proliferation inhibition, and consequently results in chemo-resistance in cervical cancer cells. A reversion of miR-375 or Ecadherin expression may be a novel therapeutic approach for overcoming chemo-resistance in cervical cancer.     

miR-219-5p targets TBXT and inhibits breast cancer cell EMT and cell migration and invasion

miR-219-5p has been reported to act as either a tumor suppressor or a tumor promoter in different cancers by targeting different genes. In the present study, we demonstrated that miR-219-5p negatively regulated the expression of TBXT, a known epithelial–mesenchymal transition (EMT) inducer, by directly binding to TBXT 3′-untranslated region. As a result of its inhibition on TBXT expression, miR-219-5p suppressed EMT and cell migration and invasion in breast cancer cells. The re-introduction of TBXT in miR-219-5p overexpressing cells decreased the inhibitory effects of miR-219 on EMT and cell migration and invasion. Moreover, miR-219-5p decreased breast cancer stem cell (CSC) marker genes expression and reduced the mammosphere forming capability of cells. Overall, our study highlighted that TBXT is a novel target of miR-219-5p. By suppressing TBXT, miR-219-5p plays an important role in EMT and cell migration and invasion of breast cancer cells.     

Overexpression of DTL enhances cell motility and promotes tumor metastasis in cervical adenocarcinoma by inducing RAC1-JNK-FOXO1 axis

Cervical adenocarcinoma is an important disease that affects young women and it has a high mortality and poor prognosis. Denticleless E3 ubiquitin protein ligase homolog (DTL) gene with oncogenic function has been evaluated in several cancers. Through this study, we aimed to clarify the clinical and molecular characteristics of cervical adenocarcinoma involving overexpression of DTL and elucidate its molecular mechanism. Bioinformatics analysis was performed through multiple databases. RNA sequencing was used to obtain differentially expressed genes after DTL was overexpressed in cells. The role of DTL in cervical adenocarcinoma was explored through in vitro and in vivo experiments. We found that DTL has an unfavorable prognostic implication for patients with cervical adenocarcinoma. Overexpression of DTL induced the migration and invasion of tumor cells in vitro and promoted intra-pulmonary metastasis in vivo. In addition, DTL activated JNK through RAC1 and upregulated FOXO1 to induce epithelial–mesenchymal transition, and the migration and invasion of tumor cells. Therefore, we conclude that overexpression of DTL enhanced cell motility and promoted tumor metastasis of cervical adenocarcinoma by regulating the RAC1-JNK-FOXO1 axis. These results suggest that DTL may become a potential therapeutic target for antitumor metastasis of cervical adenocarcinoma.Subject terms: Cancer epigenetics, Cervical cancer     

Macrophages Mediate a Switch between Canonical and Non-Canonical Wnt Pathways in Canine Mammary Tumors

Objective

According to the current hypothesis, tumor-associated macrophages (TAMs) are “corrupted” by cancer cells and subsequently facilitate, rather than inhibit, tumor metastasis. Because the molecular mechanisms of cancer cell–TAM interactions are complicated and controversial we aimed to better define this phenomenon.

Methods and Results

Using microRNA microarrays, Real-time qPCR and Western blot we showed that co-culture of canine mammary tumor cells with TAMs or treatment with macrophage-conditioned medium inhibited the canonical Wnt pathway and activated the non-canonical Wnt pathway in tumor cells. We also showed that co-culture of TAMs with tumor cells increased expression of canonical Wnt inhibitors in TAMs. Subsequently, we demonstrated macrophage-induced invasive growth patterns and epithelial–mesenchymal transition of tumor cells. Validation of these results in canine mammary carcinoma tissues (n = 50) and xenograft tumors indicated the activation of non-canonical and canonical Wnt pathways in metastatic tumors and non-metastatic malignancies, respectively. Activation of non-canonical Wnt pathway correlated with number of TAMs.

Conclusions

We demonstrated that TAMs mediate a “switch” between canonical and non-canonical Wnt signaling pathways in canine mammary tumors, leading to increased tumor invasion and metastasis.Interestingly, similar changes in neoplastic cells were observed in the presence of macrophage-conditioned medium or live macrophages. These observations indicate that rather than being “corrupted” by cancer cells, TAMs constitutively secrete canonical Wnt inhibitors that decrease tumor proliferation and development, but as a side effect, they induce the non-canonical Wnt pathway, which leads to tumor metastasis.These data challenge the conventional understanding of TAM–cancer cell interactions.