Tenascin-C induces migration and invasion through JNK/c-Jun signalling in pancreatic cancer

The serum tenascin C level is a marker of metabolic disorder-related inflammation affecting pancreatic cancer prognosis

Obesity is a risk factor for pancreatic cancer development, partly due to the tissue environment of metabolic disorder-related inflammation. We aimed to detect a tissue environment marker triggered by obesity-related metabolic disorders related to pancreatic cancer progression. In murine experiments, Bl6/j mice fed a normal diet (ND) or a high-fat diet (HFD) were orthotopically injected with mPKC1, a murine-derived pancreatic cancer cell line. We used stocked sera from 140 pancreatic cancer patients for analysis and 14 colon polyp patients as a disease control. Compared with ND-fed mice, HFD-fed mice exhibited obesity, larger tumors, and worse prognoses. RNA sequencing of tumors identified tenascin C (TNC) as a candidate obesity-related serum tissue environment marker with elevated expression in tumors of HFD-fed mice. Serum TNC levels were greater in HFD-fed mice than in ND-fed mice. In pancreatic cancer patients, serum TNC levels were greater than those in controls. The TNC-high group had more metabolic disorders and greater CA19-9 levels than did the TNC-low group. There was no relationship between serum TNC levels and disease stage. Among 77 metastatic patients treated with chemotherapy, a high serum TNC concentration was an independent poor prognostic factor. Pancreatic cancer patients with high serum TNC levels experienced progression more rapidly.

GPX3 represses pancreatic cancer cell proliferation, migration and invasion, and improves their chemo‑sensitivity by regulating the JNK/c‑Jun signaling pathway

Pancreatic cancer (PC) is a deadly and aggressive disease, which is characterized by poor prognosis. It has been reported that glutathione peroxidase 3 (GPX3) is involved in the development of several types of cancer. The present study aimed to explore the regulatory role of GPX3 in PC and uncover its underlying mechanism. Bioinformatics analysis was initially carried out to predict the expression profile of GPX3 in PC and its association with prognosis. The expression levels of GPX3 were also detected in PC cells by reverse transcription-quantitative PCR and western blot analysis. Following transfection to induce GPX3 overexpression, the proliferation ability of PC cells was assessed by Cell Counting Kit-8, colony formation and 5-ethynyl-2'-deoxyuridine incorporation assays. In addition, wound healing and Transwell assays were performed to evaluate the migration and invasion abilities of PC cells. Cell apoptosis was assessed by flow cytometric analysis. The expression levels of epithelial-mesenchymal transition (EMT)-, apoptosis-, and JNK signaling-related proteins were detected by western blot analysis. Additionally, for rescue experiments, JNK signaling was activated following cell treatment with anisomycin. The results showed that GPX3 was downregulated in PC and its expression was associated with favorable prognosis. In addition, cell transfection-induced GPX3 overexpression markedly inhibited cell proliferation, migration and invasion, and inhibited EMT. In addition, GPX3 improved the chemo-sensitivity of PC and gemcitabine (GEM)-resistant PC cells to GEM. Furthermore, GPX3 significantly suppressed JNK/c-Jun signaling in PC, while anisomycin treatment reversed the inhibitory effects of GPX3 on the malignant behavior and chemo-resistance of PC cells. The results of the present study indicated that GPX3 could serve as a tumor suppressor in PC via inhibiting JNK/c-Jun signaling, thus providing novel insights into the treatment of PC.

Icariin Induces Triple-Negative Breast Cancer Cell Apoptosis and Suppresses Invasion by Inhibiting the JNK/c-Jun Signaling Pathway

Background

Breast cancer is a common cancer worldwide. Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer characterized by a poor prognosis. Icariin (ICA) is a flavonoid glycoside purified from the natural product Epimedium, which is reported to exert an inhibitory effect on a variety of cancers. However, molecular mechanisms behind ICA suppressed TNBC remain elusive.

Methods

The curative effects of ICA on TNBC cells and potential targets were predicted by network pharmacology and molecular biology methods screening, and the mechanism of inhibition was explained through in vitro experiments such as cell function determination, Western blot analysis, molecular docking verification, etc.

Results

This study showed that ICA inhibits TNBC cell functions such as proliferation, migration, and invasion in a dose-dependent manner. ICA could induce redox-induced apoptosis in TNBC cell, as shown by ROS upregulation. As a result of network pharmacology, ICA was predicted to be able to inhibit the MAPK signaling pathway. ICA treatment inhibited the expression of JNK and c-Jun and downregulated the antiapoptotic gene cIAP-2. Our results suggested that ICA could induce apoptosis by inducing an excessive accumulation of ROS in cells and suppress TNBC cell invasion via the JNK/c-Jun signaling pathway.

Conclusion

We demonstrated that ICA can effectively inhibit cell proliferation and induced apoptosis of TNBC cells. In addition, ICA could inhibit TNBC cell invasion through the JNK/c-Jun signaling pathway. The above suggests that ICA may become a potential drug for TNBC.

Differential Expression in the Tumor Microenvironment of mRNAs Closely Associated with Colorectal Cancer Metastasis

BACKGROUND

Metastasis of colorectal cancer (CRC) is a major cause of CRC-related mortality. However, the detailed molecular mechanism of CRC metastasis remains unknown. A recent study showed that the tumor microenvironment, which includes cancer cells and the surrounding stromal cells, plays a major role in tumor invasion and metastasis. Identification of altered messenger RNA (mRNA) expression in the tumor microenvironment is essential to elucidation of the mechanisms responsible for tumor progression. This study investigated the mRNA expression of genes closely associated with metastatic CRC compared with non-metastatic CRC.

METHODS

The samples examined were divided into cancer tissue and isolated cancer stromal tissue. The study examined altered mRNA expression in the cancer tissues using The Cancer Genome Atlas (TCGA) (377cases) and in 17 stromal tissues obtained from our laboratory via stromal isolation using an array-based analysis. In addition, 259 patients with CRC were enrolled to identify the association of the candidate markers identified with the prognosis of patients with stage 2 or 3 CRC. The study examined the enriched pathways identified by gene set enrichment analysis (GSEA) based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) module in both the TCGA dataset and isolated stromal tissue.

RESULTS

As a result, whereas tenascin-C, secreted phosphoprotein 1 and laminin were expressed in metastatic CRC cells, olfactory receptors (ORs) 11H1 and OR11H4 were expressed in stromal tissue cells isolated from metastatic CRC cases. Finally, upregulated expression of tenascin-C and OR11H4 was correlated with the outcome for CRC patients.

CONCLUSION

The authors suggest that upregulated expression levels of tenascin-C and OR11H1 play an important role in CRC progression.

Fenretinide combines perturbation of signaling kinases, cell-extracellular matrix interactions and matrix metalloproteinase activation to inhibit invasion in oral squamous cell carcinoma cells

Basement membrane invasion defines malignant transformation of surface premalignancy. Treatment of oral squamous cell carcinoma (OSCC) cells with the synthetic vitamin A derivative, fenretinide (4HPR), induces numerous cancer-preventive effects including suppression of basement membrane invasion, elimination of anchorage-independent growth, disruption of actin cytoskeletal components and inhibition of the invasion-enabling focal adhesive kinase. The purpose of this study was to elucidate 4HPR's effects on additional invasion-relevant mechanisms including matrix metalloproteinase (MMP) activation and function, cell-extracellular matrix (ECM) attachments and interaction with a kinase that is essential for the epithelial-myoepithelial transformation i.e. c-Jun NH2-terminal kinase (JNK). Our data revealed that 4HPR binds with high affinity to the ATP-binding site of all three JNK isoforms with concurrent suppression of kinase function. Additional studies showed 4HPR treatment inhibited both OSCC cell-ECM adhesion and MMP activation and function. JNK downregulation and induced expression studies confirmed that the JNK3 isoform conveyed that largest impact on OSCC migration and invasion. Biodegradable polymeric implants formulated to preserve 4HPR's function and bioavailability were employed to assess 4HPR's chemopreventive impact on an OSCC tumor induction model. These studies revealed 4HPR local delivery significantly inhibited OSCC tumor size, mitotic indices and expression of the endothelial marker, erythroblast transformation-specific-related gene with concurrent increases in tumor apoptosis (cleaved caspase-3). Collectively, these data show that 4HPR suppresses invasion at multiple sites including 'outside-in' signaling, cell-ECM interactions and suppression of MMPs. These functions are also essential for physiologic function. Regulation is therefore essential and reinforces the pharmacologic advantage of local delivery chemopreventive formulations. .

Next-generation Tumor-homing Induced Neural Stem Cells as an Adjuvant to Radiation for the Treatment of Metastatic Lung Cancer

The spread of non-small cell lung cancer (NSCLC) to the leptomeninges is devastating with a median survival of only a few months. Radiation offers symptomatic relief, but new adjuvant therapies are desperately needed. Spheroidal, human induced neural stem cells (hiNeuroS) secreting the cytotoxic protein, TRAIL, have innate tumoritropic properties. Herein, we provide evidence that hiNeuroS-TRAIL cells can migrate to and suppress growth of NSCLC metastases in combination with radiation. In vitro cell tracking and post-mortem tissue analysis showed that hiNeuroS-TRAIL cells migrate to NSCLC tumors. Importantly, isobolographic analysis suggests that TRAIL with radiation has a synergistic cytotoxic effect on NSCLC tumors. In vivo, mice treated with radiation and hiNeuroS-TRAIL showed significant (36.6%) improvements in median survival compared to controls. Finally, bulk mRNA sequencing analysis showed both NSCLC and hiNeuroS-TRAIL cells showed changes in genes involved in migration following radiation. Overall, hiNeuroS-TRAIL cells +/- radiation have the capacity to treat NSCLC metastases.

The extracellular matrix molecule tenascin-C modulates cell cycle progression and motility of adult neural stem/progenitor cells from the subependymal zone

Adult neurogenesis has been described in two canonical regions of the adult central nervous system (CNS) of rodents, the subgranular zone (SGZ) of the hippocampus and the subependymal zone (SEZ) of the lateral ventricles. The stem cell niche of the SEZ provides a privileged environment composed of a specialized extracellular matrix (ECM) that comprises the glycoproteins tenascin-C (Tnc) and laminin-1 (LN1). In the present study, we investigated the function of these ECM glycoproteins in the adult stem cell niche. Adult neural stem/progenitor cells (aNSPCs) of the SEZ were prepared from wild type (Tnc^+/+) and Tnc knockout (Tnc^−/−) mice and analyzed using molecular and cell biological approaches. A delayed maturation of aNSPCs in Tnc^−/− tissue was reflected by a reduced capacity to form neurospheres in response to epidermal growth factor (EGF). To examine a potential influence of the ECM on cell proliferation, aNSPCs of both genotypes were studied by cell tracking using digital video microscopy. aNSPCs were cultivated on three different substrates, namely, poly-d-lysine (PDL) and PDL replenished with either LN1 or Tnc for up to 6 days in vitro. On each of the three substrates aNSPCs displayed lineage trees that could be investigated with regard to cell cycle length. The latter appeared reduced in Tnc^−/− aNSPCs on PDL and LN1 substrates, less so on Tnc that seemed to compensate the absence of the ECM compound to some extent. Close inspection of the lineage trees revealed a subpopulation of late dividing aNSPCs_late that engaged into cycling after a notable delay. aNSPCs_late exhibited a clearly different morphology, with a larger cell body and conspicuous processes. aNSPCs_late reiterated the reduction in cell cycle length on all substrates tested, which was not rescued on Tnc substrates. When the migratory activity of aNSPC-derived progeny was determined, Tnc^−/− neuroblasts displayed significantly longer migration tracks. This was traced to an increased rate of migration episodes compared to the wild-type cells that rested for longer time periods. We conclude that Tnc intervenes in the proliferation of aNSPCs and modulates the motility of neuroblasts in the niche of the SEZ.

Metastasis and MAPK Pathways

Cancer is a leading cause of death worldwide. In many cases, the treatment of the disease is limited due to the metastasis of cells to distant locations of the body through the blood and lymphatic drainage. Most of the anticancer therapeutic options focus mainly on the inhibition of tumor cell growth or the induction of cell death, and do not consider the molecular basis of metastasis. The aim of this work is to provide a comprehensive review focusing on cancer metastasis and the mitogen-activated protein kinase (MAPK) pathway (ERK/JNK/P38 signaling) as a crucial modulator of this process.

Mechanical Stress Signaling in Pancreatic Cancer Cells Triggers p38 MAPK- and JNK-Dependent Cytoskeleton Remodeling and Promotes Cell Migration via Rac1/cdc42/Myosin II

Advanced or metastatic pancreatic cancer is highly resistant to existing therapies, and new treatments are urgently needed to improve patient outcomes. Current studies focus on alternative treatment approaches that target the abnormal microenvironment of pancreatic tumors and the resulting elevated mechanical stress in the tumor interior. Nevertheless, the underlying mechanisms by which mechanical stress regulates pancreatic cancer metastatic potential remain elusive. Herein, we used a proteomic assay to profile mechanical stress-induced signaling cascades that drive the motility of pancreatic cancer cells. Proteomic analysis, together with selective protein inhibition and siRNA treatments, revealed that mechanical stress enhances cell migration through activation of the p38 MAPK/HSP27 and JNK/c-Jun signaling axes, and activation of the actin cytoskeleton remodelers: Rac1, cdc42, and myosin II. In addition, mechanical stress upregulated transcription factors associated with epithelial-to-mesenchymal transition and stimulated the formation of stress fibers and filopodia. p38 MAPK and JNK inhibition resulted in lower cell proliferation and more effectively blocked cell migration under mechanical stress compared with control conditions. The enhanced tumor cell motility under mechanical stress was potently reduced by cdc42 and Rac1 silencing with no effects on proliferation. Our results highlight the importance of targeting aberrant signaling in cancer cells that have adapted to mechanical stress in the tumor microenvironment, as a novel approach to effectively limit pancreatic cancer cell migration.

IMPLICATIONS

Our findings highlight that mechanical stress activated the p38 MAPK and JNK signaling axis and stimulated pancreatic cancer cell migration via upregulation of the actin cytoskeleton remodelers cdc42 and Rac1.

Tenascin-C induction exacerbates post-stroke brain damage

The role of tenascin-C (TNC) in ischemic stroke pathology is not known despite its prognostic association with cerebrovascular diseases. Here, we investigated the effect of TNC knockdown on post-stroke brain damage and its putative mechanism of action in adult mice of both sexes. Male and female C57BL/6 mice were subjected to transient middle cerebral artery occlusion and injected (i.v.) with either TNC siRNA or a negative (non-targeting) siRNA at 5 min after reperfusion. Motor function (beam walk and rotarod tests) was assessed between days 1 and 14 of reperfusion. Infarct volume (T2-MRI), BBB damage (T1-MRI with contrast), and inflammatory markers were measured at 3 days of reperfusion. The TNC siRNA treated cohort showed significantly curtailed post-stroke TNC protein expression, motor dysfunction, infarction, BBB damage, and inflammation compared to the sex-matched negative siRNA treated cohort. These results demonstrate that the induction of TNC during the acute period after stroke might be a mediator of post-ischemic inflammation and secondary brain damage independent of sex.

The Functional Role of Extracellular Matrix Proteins in Cancer

The extracellular matrix (ECM) is highly dynamic as it is constantly deposited, remodeled and degraded to maintain tissue homeostasis. ECM is a major structural component of the tumor microenvironment, and cancer development and progression require its extensive reorganization. Cancerized ECM is biochemically different in its composition and is stiffer compared to normal ECM. The abnormal ECM affects cancer progression by directly promoting cell proliferation, survival, migration and differentiation. The restructured extracellular matrix and its degradation fragments (matrikines) also modulate the signaling cascades mediated by the interaction with cell-surface receptors, deregulate the stromal cell behavior and lead to emergence of an oncogenic microenvironment. Here, we summarize the current state of understanding how the composition and structure of ECM changes during cancer progression. We also describe the functional role of key proteins, especially tenascin C and fibronectin, and signaling molecules involved in the formation of the tumor microenvironment, as well as the signaling pathways that they activate in cancer cells.

Tumor Microenvironment in Pancreatic Intraepithelial Neoplasia

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive neoplasm with a poor survival rate. This is mainly due to late detection, which substantially limits therapy options. A better understanding of the early phases of pancreatic carcinogenesis is fundamental for improving patient prognosis in the future. In this article, we focused on the tumor microenvironment (TME), which provides the biological niche for the development of PDAC from its most common precursor lesions, PanIN (pancreatic intraepithelial neoplasias).

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive tumors with a poor prognosis. A characteristic of PDAC is the formation of an immunosuppressive tumor microenvironment (TME) that facilitates bypassing of the immune surveillance. The TME consists of a desmoplastic stroma, largely composed of cancer-associated fibroblasts (CAFs), immunosuppressive immune cells, immunoregulatory soluble factors, neural network cells, and endothelial cells with complex interactions. PDAC develops from various precursor lesions such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasms (IPMN), mucinous cystic neoplasms (MCN), and possibly, atypical flat lesions (AFL). In this review, we focus on the composition of the TME in PanINs to reveal detailed insights into the complex restructuring of the TME at early time points in PDAC progression and to explore ways of modifying the TME to slow or even halt tumor progression.

The long non-coding RNA ET-20 mediates EMT by impairing desmosomes in breast cancer cells

The vast majority of breast cancer-associated deaths are due to metastatic spread of cancer cells, a process aided by epithelial-to-mesenchymal transition (EMT). Mounting evidence has indicated that long non-coding RNAs (lncRNAs) also contribute to tumor progression. We report the identification of 114 novel lncRNAs that change their expression during TGFβ-induced EMT in murine breast cancer cells (referred to as EMT-associated transcripts; ETs). Of these, the ET-20 gene localizes in antisense orientation within the tenascin C (Tnc) gene locus. TNC is an extracellular matrix protein that is critical for EMT and metastasis formation. Both ET-20 and Tnc are regulated by the EMT master transcription factor Sox4. Notably, ablation of ET-20 lncRNA effectively blocks Tnc expression and with it EMT. Mechanistically, ET-20 interacts with desmosomal proteins, thereby impairing epithelial desmosomes and promoting EMT. A short transcript variant of ET-20 is shown to be upregulated in invasive human breast cancer cell lines, where it also promotes EMT. Targeting ET-20 appears to be a therapeutically attractive lead to restrain EMT and breast cancer metastasis in addition to its potential utility as a biomarker for invasive breast cancer.

Involvement of integrin-activating peptides derived from tenascin-C in colon cancer progression

Tenascin-C (TNC) is an adhesion modulatory protein present in the extracellular matrix that is highly expressed in several malignancies, including colon cancer. Although TNC is considered a negative prognostic factor for cancer patients, the substantial role of the TNC molecule in colorectal carcinogenesis and its malignant progression is poorly understood. We previously found that TNC has a cryptic functional site and that a TNC peptide containing this site, termed TNIIIA2, can potently and persistently activate beta1-integrins. In contrast, the peptide FNIII14, which contains a cryptic bioactive site within the fibronectin molecule, can inactivate beta1-integrins. This review presents the role of TNC in the development of colitis-associated colorectal cancer and in the malignant progression of colon cancer, particularly the major involvement of its cryptic functional site TNIIIA2. We propose new possible prophylactic and therapeutic strategies based on inhibition of the TNIIIA2-induced beta1-integrin activation by peptide FNIII14.

Induction of cellular senescence in fibroblasts through β1-integrin activation by tenascin-C-derived peptide and its protumor effect

Tenascin-C is upregulated during inflammation and tumorigenesis, and its expression level is correlated with a poor prognosis in several malignancies. Nevertheless, the substantial role of tenascin-C in cancer progression is poorly understood. Previously, we found that a peptide derived from tenascin-C, termed TNIIIA2, acts directly on tumor cells to activate β1-integrin and induce malignant progression. Here, we show that β1-integrin activation by TNIIIA2 in human fibroblasts indirectly contributes to cancer progression through the induction of cellular senescence. Prolonged treatment of fibroblasts with TNIIIA2 induced cellular senescence, as characterized by the suppression of cell growth and the induction of senescence-associated-β-galactosidase and p16^INK4a expression. The production of reactive oxygen species and subsequent DNA damage were responsible for the TNIIIA2-induced senescence of fibroblasts. Interestingly, peptide FNIII14, which inactivates β1-integrin, inhibited fibroblast senescence induced not only by TNIIIA2 but also by H₂O₂, suggesting that β1-integrin activation plays a critical role in the induction of senescence in fibroblasts. Moreover, TNIIIA2-induced senescent fibroblasts secreted heparin-binding epidermal growth factor-like growth factor (HB-EGF), which caused preneoplastic epithelial HaCaT cells to acquire malignant properties, including colony-forming and focus-forming abilities. Thus, our study demonstrates that tenascin-C-derived peptide TNIIIA2 induces cellular senescence in fibroblasts through β1-integrin activation, causing cancer progression via the secretion of humoral factors such as HB-EGF.

ZSCAN16-AS1 expedites hepatocellular carcinoma progression via modulating the miR-181c-5p/SPAG9 axis to activate the JNK pathway

Hepatocellular carcinoma (HCC) is generally known as one of the most common cancers in the world. Nowadays, interventional therapies such as transcatheter arterial chemoembolization (TACE) have emerged as an efficient therapy for HCC patients. Accumulating evidence has unveiled that long non-coding RNAs (lncRNAs) are crucial regulators in HCC progression. Nonetheless, the biological function of lncRNA zinc finger and SCAN domain containing 16 antisense RNA 1 (ZSCAN16-AS1) in HCC has not been systematically clarified. RT-qPCR was used to test ZSCAN16-AS1 expression in HCC cells. The biological functions of RP11-757 G1.5 on HCC cell proliferation, migration, invasion and apoptosis were investigated by colony formation, EdU, CCK-8 and transwell assays, as well as flow cytometry analysis. RNA immunoprecipitation (RIP), RNA pull-down and luciferase reporter assays were utilized to explore the specific mechanism of ZSCAN16-AS1. ZSCAN16-AS1 was significantly up-regulated in HCC cells. ZSCAN16-AS1 silence inhibited HCC cell proliferation, migration and invasion, while it accelerated HCC cell apoptosis. ZSCAN16-AS1 worked as a competing endogenous RNA (ceRNA) to regulate sperm associated antigen 9 (SPAG9) expression through sponging miR-181 c-5p. Moreover, SPAG9 could activate the c-Jun-N-terminal kinase (JNK) pathway. Taken together, our study elucidated that ZSCAN16-AS1 expedited HCC progression via modulating the miR-181 c-5p/SPAG9 axis to activate the JNK pathway, which might be a highly potential HCC therapy and treatment target.

The Extracellular Matrix Glycoprotein Tenascin C and Adult Neurogenesis

Tenascin C (TnC) is a glycoprotein highly expressed in the extracellular matrix (ECM) during development and in the adult central nervous system (CNS) in regions of active neurogenesis, where neuron development is a tightly regulated process orchestrated by extracellular matrix components. In addition, newborn cells also communicate with glial cells, astrocytes and microglia, indicating the importance of signal integration in adult neurogenesis. Although TnC has been recognized as an important molecule in the regulation of cell proliferation and migration, complete regulatory pathways still need to be elucidated. In this review we discuss the formation of new neurons in the adult hippocampus and the olfactory system with specific reference to TnC and its regulating functions in this process. Better understanding of the ECM signaling in the niche of the CNS will have significant implications for regenerative therapies.

Human Mesenchymal Stem Cell-Derived Exosomal microRNA-143 Promotes Apoptosis and Suppresses Cell Growth in Pancreatic Cancer via Target Gene Regulation

Background

This study aimed to explore the regulatory mechanism of hsa-miR-143-3p and lncRNA RP11-363N22.3-functioning upstream of KRAS-in exosomes derived from human mesenchymal stem cells (hMSCs) in pancreatic cancer.

Methods

Western blotting and quantitative PCR were used to determine gene expression. In vitro, cell proliferation, apoptosis, and cell cycle and invasion were evaluated using CCK-8 assay, flow cytometry, and transwell assays, respectively. In vivo, the effect of hsa-miR143-3p was investigated using a tumorigenesis test in nude mice. The association between hsa-miR-143-3p and lncRNA RP11-363N22.3 was investigated using the dual-luciferase assay.

Results

hsa-miR-143-3p expression significantly increased in hMSC exosomes than in those in human pancreatic cancer cell line (CFPAC-1) exosomes. In vitro, compared to the MOCK (CFPAC-1 only) group, cell proliferation and invasion were inhibited and apoptosis was induced in the inhibitor NC (CFPAC-1 + MSC-hsa-miR-3p inhibitor NC) group, while these changes were reversed in the inhibitor (CFPAC-1 + MSC-hsa-miR-3p inhibitor) group. The expression of lncRNA RP11-363N22.3 and genes related to miR-143 significantly decreased in the inhibitor NC group compared to the MOCK group, and increased in the inhibitor group compared to inhibitor NC group. A targeted combinatorial effect was observed between lncRNA RP11-363N22.3 and hsa-miR-143-3p. In vivo, the tumor volume of the mimics (CFPAC-1 + MSC-hsa-miR-143-3p mimics) group was smaller than that of the mimics NC (CFPAC-1 + MSC-hsa-miR-143-3p mimics NC) and MOCK groups. H&E staining showed that there were no obvious pathological changes in MOCK and mimic NC groups, while cell necrosis was seen in some regions in mimic groups.

Conclusion

hsa-miR-143-3p may promote apoptosis and suppress cell growth and invasion in pancreatic cancer.

Biologically Active TNIIIA2 Region in Tenascin-C Molecule: A Major Contributor to Elicit Aggressive Malignant Phenotypes From Tumors/Tumor Stroma

Tenascin (TN)-C is highly expressed specifically in the lesions of inflammation-related diseases, including tumors. The expression level of TN-C in tumors and the tumor stroma is positively correlated with poor prognosis. However, no drugs targeting TN-C are currently clinically available, partly because the role of TN-C in tumor progression remains controversial. TN-C harbors an alternative splicing site in its fibronectin type III repeat domain, and its splicing variants including the type III-A2 domain are frequently detected in malignant tumors. We previously identified a biologically active region termed TNIIIA2 in the fibronectin type III-A2 domain of TN-C molecule and showed that this region is involved in promoting firm and persistent cell adhesion to fibronectin. In the past decade, through the exposure of various cell lines to peptides containing the TNIIIA2 region, we have published reports demonstrating the ability of the TNIIIA2 region to modulate distinct cellular activities, including survival/growth, migration, and invasion. Recently, we reported that the signals derived from TNIIIA2-mediated β1 integrin activation might play a crucial role for inducing malignant behavior of glioblastoma (GBM). GBM cells exposed to the TNIIIA2 region showed not only exacerbation of PDGF-dependent proliferation, but also acceleration of disseminative migration. On the other hand, we also found that the pro-inflammatory phenotypic changes were promoted when macrophages are stimulated with TNIIIA2 region in relatively low concentration and resulting MMP-9 upregulation is needed to release of the TNIIIA2 region from TN-C molecule. With the contribution of TNIIIA2-stimulated macrophages, the positive feedback spiral loop, which consists of the expression of TN-C, PDGF, and β1 integrin, and TNIIIA2 release, seemed to be activated in GBM with aggressive malignancy. Actually, the growth of transplanted GBM grafts in mice was significantly suppressed via the attenuation of β1 integrin activation. In this review, we thus introduce that the TNIIIA2 region has a significant impact on malignant progression of tumors by regulating cell adhesion. Importantly, it has been demonstrated that the TNIIIA2 region exerts unique biological functions through the extremely strong activation of β1-integrins and their long-lasting duration. These findings prompt us to develop new therapeutic agents targeting the TNIIIA2 region.

Protein Kinase D1, Reduced in Human Pancreatic Tumors, Increases Secretion of Small Extracellular Vesicles From Cancer Cells That Promote Metastasis to Lung in Mice

BACKGROUND & AIMS

Pancreatic tumor cells release small extracellular vesicles (sEVs, exosomes) that contain lipids and proteins, RNA, and DNA molecules that might promote formation of metastases. It is not clear what cargo these vesicles contain and how they are released. Protein kinase D1 (PRKD1) inhibits cell motility and is believed to be dysregulated in pancreatic ductal adenocarcinomas. We investigated whether it regulates production of sEVs in pancreatic cancer cells and their ability to form premetastatic niches for pancreatic cancer cells in mice.

METHODS

We analyzed data from UALCAN and human pancreatic tissue microarrays to compare levels of PRKD1 between tumor and nontumor tissues. We studied mice with pancreas-specific disruption of Prkd1 (PRKD1^KO mice), mice that express oncogenic KRAS (KC mice), and KC mice with disruption of Prkd1 (PRKD1^KO-KC mice). Subcutaneous xenograft tumors were grown in NSG mice from Panc1 cells; some mice were then given injections of sEVs. Pancreata and lung tissues from mice were analyzed by histology, immunohistochemistry, and/or quantitative polymerase chain reaction; we performed nanoparticle tracking analysis of plasma sEVs. The Prkd1 gene was disrupted in Panc1 cells using CRISPR-Cas9 or knocked down with small hairpin RNAs, or PRKD1 activity was inhibited with the selective inhibitor CRT0066101. Pancreatic cancer cell lines were analyzed by gene-expression microarray, quantitative polymerase chain reaction, immunoblot, and immunofluorescence analyses. sEVs secreted by Panc1 cell lines were analyzed by flow cytometry, transmission electron microscopy, and mass spectrometry.

RESULTS

Levels of PRKD1 were reduced in human pancreatic ductal adenocarcinoma tissues compared with nontumor tissues. PRKD1^KO-KC mice developed more pancreatic intraepithelial neoplasia, at a faster rate, than KC mice, and had more lung metastases and significantly shorter average survival time. Serum from PRKD1^KO-KC mice had increased levels of sEVs compared with KC mice. Pancreatic cancer cells with loss or inhibition of PRKD1 increased secretion of sEVs; loss of PRKD1 reduced phosphorylation of its substrate, cortactin, resulting in increased F-actin levels at the plasma membrane. sEVs from cells with loss or reduced expression of PRKD1 had altered content, and injection of these sEVs into mice increased metastasis of xenograft tumors to lung, compared with sEVs from pancreatic cells that expressed PRKD1. PRKD1-deficient pancreatic cancer cells showed increased loading of integrin α6β4 into sEVs-a process that required CD82.

CONCLUSIONS

Human pancreatic ductal adenocarcinoma has reduced levels of PRKD1 compared with nontumor pancreatic tissues. Loss of PRKD1 results in reduced phosphorylation of cortactin in pancreatic cancer cell lines, resulting in increased in F-actin at the plasma membrane and increased release of sEVs, with altered content. These sEVs promote metastasis of xenograft and pancreatic tumors to lung in mice.

Mechanically stressed cancer microenvironment: Role in pancreatic cancer progression

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal solid malignancies in the world due to its insensitivity to current therapies and its propensity to metastases from the primary tumor mass. This is largely attributed to its complex microenvironment composed of unique stromal cell populations and extracellular matrix (ECM). The recruitment and activation of these cell populations cause an increase in deposition of ECM components, which highly influences the behavior of malignant cells through disrupted forms of signaling. As PDAC progresses from premalignant lesion to invasive carcinoma, this dynamic landscape shields the mass from immune defenses and cytotoxic intervention. This microenvironment influences an invasive cell phenotype through altered forms of mechanical signaling, capable of enacting biochemical changes within cells through activated mechanotransduction pathways. The effects of altered mechanical cues on malignant cell mechanotransduction have long remained enigmatic, particularly in PDAC, whose microenvironment significantly changes over time. A more complete and thorough understanding of PDAC's physical surroundings (microenvironment), mechanosensing proteins, and mechanical properties may help in identifying novel mechanisms that influence disease progression, and thus, provide new potential therapeutic targets.

Tenascin-C predicts poor outcomes for patients with colorectal cancer and drives cancer stemness via Hedgehog signaling pathway

Background

Tenascin-C (TNC) is an extracellular matrix protein that is widely expressed in the stromal fibroblasts of various cancers. However, the roles of TNC in colorectal cancer (CRC) cells remain unclear.

Methods

The expression of TNC, cancer stem cell-like (CSC) and cell cycle markers, and Hedgehog (HH) signaling pathway genes were assessed in 100 paraffin embedded clinical CRC patient tissues using immunohistochemistry. The interaction between TNC and CSC marker or HH related genes in CRC cells were detected by immunofluorescence. Cell cycle distribution was measured by flow cytometry. Migration and invasion were evaluated by transwell assays. The expressions of TNC, CSC marker, and HH related proteins were analyzed by western blot.

Results

TNC expression was markedly upregulated in CRC tissues, and was associated with worse clinical outcomes. TNC overexpression was positively associated with CSC marker LSD1, cell cycle markers CDK4 and p16, and HH signaling pathway related genes SMO and GLI1 in clinical CRC tissue samples. TNC silencing downregulated the expression of the CSC marker LSD1, and the proliferation, migration, and invasion of CRC cells. Interestingly, the GLI1 inhibitor GANT61 strongly inhibited the expression of TNC in CRC cells.

Conclusions

TNC may drive tumor progression and is involved in CSC properties via the HH signaling pathway. TNC has potential value in the evaluation of poor prognosis in CRC.

Anticancer Activities of Meroterpenoids Isolated from the Brown Alga Cystoseira usneoides against the Human Colon Cancer Cells HT-29

Colorectal cancer (CRC) is one of the most common types of cancers and a leading cause of cancer death worldwide. The current treatment for CRC mainly involves surgery, radiotherapy, and chemotherapy. However, due to the side effects and the emergence of drug resistance, the search for new anticancer agents, pharmacologically safe and effective, is needed. In the present study, we have investigated the anticancer effects of eight algal meroterpenoids (AMTs, 1-8) isolated from the brown seaweed Cystoseira usneoides and their underlying mechanisms of action using HT-29, a highly metastatic human colon cancer cell line. All the tested meroterpenoids inhibited the growth of HT-29 malignant cells and were less toxic towards non-cancer colon cells, with the AMTs 1 and 5 exhibiting selectivity indexes of 5.26 and 5.23, respectively. Treatment of HT-29 cells with the AMTs 1, 2, 3, 4, 5, and 7 induced cell cycle arrest in G2/M phase and, in some instances, apoptosis (compounds 2, 3, and 5). Compounds 1-8 also exhibited significant inhibitory effects on the migration and/or invasion of colon cancer cells. Mechanistic analysis demonstrated that the AMTs 1, 2, 5, 6, 7, and 8 reduced phosphorylation levels of extracellular signal-regulated kinase (ERK) and the AMTs 2, 3, 4, 5, 7, and 8 decreased phosphorylation of c-JUN N-terminal kinase (JNK). Moreover, the AMTs 1, 2, 3, 4, 7, and 8 inhibited phosphorylation levels of protein kinase B (AKT) in colon carcinoma cells. These results provide new insights into the mechanisms and functions of the meroterpenoids of C. usneoides, which exhibit an anticancer effect on HT-29 colon cancer cells by inducing cell cycle arrest and apoptosis via the downregulation of ERK/JNK/AKT signaling pathways.

c-Jun Overexpression Accelerates Wound Healing in Diabetic Rats by Human Umbilical Cord-Derived Mesenchymal Stem Cells

Objective

Mesenchymal stem cells (MSCs) are considered a promising therapy for wound healing. Here, we explored the role of c-Jun in diabetic wound healing using human umbilical cord-derived MSCs (hUC-MSCs).

Methods

Freshly isolated hUC-MSCs were subjected to extensive in vitro subcultivation. The cell proliferative and migratory capacities were assessed by the Cell Counting Kit-8 and scratch assays, respectively. c-Jun expression was evaluated by RT-PCR and western blot analysis. The function of c-Jun was investigated with lentivirus transduction-based gene silencing and overexpression. Diabetes mellitus was induced in SD rats on a high-glucose/fat diet by streptozocin administration. Wounds were created on the dorsal skin. The effects of c-Jun silencing and overexpression on wound closure by hUC-MSCs were examined. Reepithelialization and angiogenesis were assessed by histological and immunohistochemical analysis, respectively. Platelet-derived growth factor A (PDGFA), hepatocyte growth factor (HGF), and vascular endothelial growth factor (VEGF) levels were determined by western blot analysis.

Results

hUC-MSCs showed gradually decreased cell proliferation, migration, and c-Jun expression during subcultivation. c-Jun silencing inhibited cell proliferation and migration, while c-Jun overexpression enhanced proliferation but not migration. Compared with untransduced hUC-MSCs, local subcutaneous injection of c-Jun-overexpressing hUC-MSCs accelerated wound closure, enhanced angiogenesis and reepithelialization at the wound bed, and increased PDGFA and HGF levels in wound tissues.

Conclusion

c-Jun overexpression promoted hUC-MSC proliferation and migration in vitro and accelerated diabetic wound closure, reepithelization, and angiogenesis by hUC-MSCs in vivo. These beneficial effects of c-Jun overexpression in diabetic wound healing by hUC-MSCs were at least partially mediated by increased PDGFA and HGF levels in wound tissues.

Tenascin C regulates multiple microglial functions involving TLR4 signaling and HDAC1

Tenascin C (Tnc) is an extracellular matrix glycoprotein, expressed in the CNS during development, as well as in the setting of inflammation, fibrosis and cancer, which operates as an activator of Toll-like receptor 4 (TLR4). Although TLR4 is highly expressed in microglia, the effect of Tnc on microglia has not been elucidated to date. Herein, we demonstrate that Tnc regulates microglial phagocytic activity at an early postnatal age (P4), and that this process is partially dependent on microglial TLR4 expression. We further show that Tnc regulates proinflammatory cytokine/chemokine production, chemotaxis and phagocytosis in primary microglia in a TLR4-dependent fashion. Moreover, Tnc induces histone-deacetylase 1 (HDAC1) expression in microglia, such that HDAC1 inhibition by MS-275 decreases Tnc-induced microglial IL-6 and TNF-α production. Finally, Tnc^-/- cortical microglia have reduced HDAC1 expression levels at P4. Taken together, these findings establish Tnc as a regulator of microglia function during early postnatal development.

Tenascin-C expression contributes to pediatric brainstem glioma tumor phenotype and represents a novel biomarker of disease

Diffuse intrinsic pontine glioma (DIPG), an infiltrative, high grade glioma (HGG) affecting young children, has the highest mortality rate of all pediatric cancers. Despite treatment, average survival is less than twelve months, and five-year survival under 5%. We previously detected increased expression of Tenascin-C (TNC) protein in DIPG cerebrospinal fluid and tumor tissue relative to normal specimens. TNC is an extracellular matrix (ECM) glycoprotein that mediates cell-matrix interactions, guides migrating neurons during normal brain development and is thought to maintain the periventricular stem cell niche in the developing brain. Tumor TNC expression is reported in adult glioma and other cancers. However, the pattern and effects of TNC expression in DIPG has not been previously explored. Here, we characterize TNC expression in patient derived pediatric supratentorial HGG (n = 3) and DIPG (n = 6) cell lines, as well as pediatric glioma tumor (n = 50) and normal brain tissue specimens (n = 3). We found tumor specific TNC gene and protein overexpression that directly correlated with higher tumor grade (WHO III and IV, p = 0.05), H3K27 M mutation (p = 0.012), shorter progression free survival (p = 0.034), and poorer overall survival (0.041) in association with these factors. TNC knockdown via lentiviral shRNA transfection of HGG (n = 1) and DIPG (n = 3) cell lines resulted in decreased cell proliferation, migration, and invasion in vitro (p < 0.01), while TNC cDNA transfection resulted in increased cell migration, invasion and proliferation (p < 0.01) as well as altered cell morphology in H3K27 M mutant DIPG lines. Whole transcriptome sequencing analysis (RNA-Seq) on DIPG (n = 3) and HGG (n = 2) cell lines after TNC cDNA, shRNA, and empty vector control transfection revealed the effects of TNC expression level on global gene expression profiles. Together, our findings reveal TNC expression in DIPG in association with H3K27 M mutation and VEGF signaling, and suggest that TNC may contribute to DIPG tumor phenotype, and serve as a clinically detectable biomarker for DIPG.

Cancer-Associated Fibroblasts Build and Secure the Tumor Microenvironment

Tumor cells reside in a highly complex and heterogeneous tumor microenvironment (TME), which is composed of a myriad of genetically stable non-cancer cells, including fibroblasts, immune cells, endothelial cells, and epithelial cells, and a tumor-specific extracellular matrix (ECM). Cancer-associated fibroblasts (CAFs), as an abundant and active stromal cell population in the TME, function as the signaling center and remodeling machine to aid the creation of a desmoplastic tumor niche. Although there is no denial that the TME and CAFs may have anti-tumor effects as well, a great deal of findings reported in recent years have convincingly revealed the tumor-promoting effects of CAFs and CAF-derived ECM proteins, enzymes, chemical factors and other downstream effectors. While there is growing enthusiasm for the development of CAF-targeting therapies, a better understanding of the complexities of CAF-ECM and CAF-cancer cell interactions is necessary before novel therapeutic strategies targeting the malignant tumor “soil” can be successfully implemented in the clinic.

PUF60 accelerates the progression of breast cancer through downregulation of PTEN expression

Background

PUF60 is a splicing variant of far upstream element binding protein 1-interacting repressor, which is abnormally expressed in a variety of tumors and is closely involved in their progression. However, whether PUF60 participates in the occurrence and development of breast cancer remains unknown. Therefore, the objective of the current study is to explore the effects and mechanism of PUF60 in the progression of breast cancer.

Methods

PUF60 expression patterns in breast cancer tissues and cells were determined by RT-PCR and Western blotting. The relationship between PUF60 expression and patients' clinical features and outcome was evaluated to assess the potential of PUF60 as a marker for progression and prognosis prediction. CCK-8, flow cytometry, transwell and in vivo tumor formation assays were used to detect cell proliferation, apoptosis, migration, invasion and tumorigenesis. The effects of PUF60 on the activation of PTEN/PI3K/AKT were also evaluated by Western blotting and immunofluorescence assays.

Results

The expression of PUF60 was elevated in breast cancer tissue samples and cell lines, and its high expression was closely associated with the high incidence of lymph node metastasis and advanced TNM stage. Besides, upregulation of PUF60 with lentivirus infection significantly increased the growth, migration, and invasion and repressed the apoptosis of breast cancer HCC1937 and MDA-MB-231 cells, while silencing of PUF60 with shRNA showed the opposite results. Moreover, PUF60 upregulation promoted the expression of p-AKT, PI3K, and mTOR, while decreased PTEN expression through inhibiting its stability and enhancing its ubiquitination. Furthermore, upregulation of PUF60 promoted the tumorigenesis in vivo, whereas this effect was impaired when PTEN expression was upregulated in MDA-MB-231 and HCC1937 cells.

Conclusion

This study demonstrates that PUF60 is highly expressed in breast cancer; upregulation of PUF60 accelerates the progression of breast cancer through PTEN inhibition.

Tenascin-C expression is significantly associated with the progression and prognosis in gastric GISTs

Tenascin-C (TNC), an extracellular matrix glycoprotein, has been implicated in progression of various types of cancer. However, few reports exist on TNC expression in gastrointestinal stromal tumors (GISTs). We here attempted to investigate the expression pattern and prognostic significance of TNC in gastric GISTs. We studied TNC expression in 122 gastric GISTs tissue samples by immunohistochemistry, and examined the correlations of TNC expression with clinicopathological parameters and survival of gastric GISTs. The TNC-high expression was observed in 30 (24.6%) of 122 of gastric GISTs. The high levels of TNC expression in gastric GISTs was significantly associated with tumor size (P < .001), multivisceral resection (P = .006), metastasis at initial diagnosis (P = .006), mitotic count (P = .002) and NIH risk classification (P = .015). The TNC mRNA and protein levels were found to significantly downregulated in tumors without progression compared to those tumors which occurred tumor progression during the follow-up period (P < .05). As for the prognostic analysis, it revealed that tumor size, mitotic count, surgical margins, multivisceral resection, and TNC expression were independent predictors of PFS for gastric GISTs (P < .05). The overexpression of TNC may be as a possible marker for the metastatic potential of gastric GISTs patients.

Tenascin-C Modulates Cell Cycle Progression to Enhance Tumour Cell Proliferation through AKT/FOXO1 Signalling in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is a disease with an extremely poor prognosis that is characterized by a rich extracellular matrix (ECM). Tenascin-C (TNC) is a component of the ECM and plays a role in tumour progression. In this study, we reported that TNC is overexpressed in PDAC tissues and is correlated with tumour stage and cyclin D1 expression. Cyclin D1 is key regulator of the cell cycle G1/S transition. Further experiments revealed that TNC promotes G1/S transition through AKT signalling. TNC/AKT increases the expression of cyclin D1 by enhancing the transcriptional activity of β-catenin, whereas the translocation of FOXO1 from the nucleus results in the downregulation of p27^Kip1. Cyclin D1 and p27^Kip1 regulate the activity of cyclin D1-CDK4 complexes and retinoblastoma (Rb), and then they stimulate the progression of G1/S transition and tumour cell proliferation. In conclusion, TNC exerts its activating effect on the proliferation of pancreatic cancer cells in vitro and in vivo through its functional target AKT/FOXO1/β-catenin. The molecular mechanisms that drive PDAC progression will be useful for the development of molecular markers and the evaluation of patient prognosis.

Intestinal microbiota enhances pancreatic carcinogenesis in preclinical models

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the United States yet data are scant regarding host factors influencing pancreatic carcinogenesis. Increasing evidence support the role of the host microbiota in carcinogenesis but its role in PDAC is not well established. Herein, we report that antibiotic-mediated microbial depletion of KrasG12D/PTENlox/+ mice showed a decreased proportion of poorly differentiated tumors compared to microbiota-intact KrasG12D/PTENlox/+ mice. Subsequent 16S rRNA PCR showed that ~50% of KrasG12D/PTENlox/+ mice with PDAC harbored intrapancreatic bacteria. To determine if a similar observation in humans correlates with presence of PDAC, benign and malignant human pancreatic surgical specimens demonstrated a microbiota by 16S bacterial sequencing and culture confirmation. However, the microbial composition did not differentiate PDAC from non-PDAC tissue. Furthermore, murine pancreas did not naturally acquire a pancreatic microbiota, as germ-free mice transferred to specific pathogen-free housing failed to acquire intrapancreatic bacteria over time, which was not augmented by a murine model of colitis. Finally, antibiotic-mediated microbial depletion of Nod-SCID mice, compared to microbiota-intact, showed increased time to PDAC xenograft formation, smaller tumors, and attenuated growth. Interestingly, both xenograft cohorts were devoid of intratumoral bacteria by 16S rRNA PCR, suggesting that intrapancreatic/intratumoral microbiota is not the sole driver of PDAC acceleration. Xenografts from microbiota-intact mice demonstrated innate immune suppression by immunohistochemistry and differential regulation of oncogenic pathways as determined by RNA sequencing. Our work supports a long-distance role of the intestinal microbiota on PDAC progression and opens new research avenues regarding pancreatic carcinogenesis.

Characterization of fibroblasts from hypertrophied right ventricle of pulmonary hypertensive rats

Pulmonary arterial hypertension (PAH), which is characterized by an elevation of pulmonary arterial resistance, leads to a lethal right heart failure. It is an urgent issue to clarify the pathogenesis of PAH-induced right heart failure. The present study aimed to elucidate the characteristics of cardiac fibroblasts (CFs) isolated from hypertrophied right ventricles of monocrotaline (MCT)-induced PAH model rats. CFs were isolated from the right ventricles of MCT-injected rats (MCT-CFs) and saline-injected control rats (CONT-CFs). Expression of α-smooth muscle actin and collagen type I in MCT-CFs was lower than that in CONT-CFs. On the other hand, proliferation, migration, and matrix metalloproteinase (MMP)-9 production were significantly enhanced in MCT-CFs. In MCT-CFs, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK), and Ca²⁺/calmodulin-dependent protein kinase (CaMK) II was significantly enhanced. In addition to mRNA expression of Orai1, a Ca²⁺ release-activated Ca²⁺ channel, and stromal interaction molecules (STIM) 1, an endoplasmic reticulum Ca²⁺ sensor, the associated store-operated Ca²⁺ entry (SOCE) was significantly higher in MCT-CFs than CONT-CFs. Pharmacological inhibition of ERK1/2 pathway prevented the enhanced proliferation of MCT-CFs. The enhanced migration of MCT-CFs was prevented by a pharmacological inhibition of ERK1/2, JNK, CaMKII, or SOCE pathway. The enhanced MMP-9 production in MCT-CFs was prevented by a pharmacological inhibition of ERK1/2, CaMKII, or SOCE pathway but not JNK. The present results suggested that MCT-CFs exhibit proliferative and migratory phenotypes perhaps through multiple signaling pathways. This study for the first time determined the characteristics of CFs isolated from hypertrophied right ventricles of MCT-induced PAH model rats.

Expression of annexin II and stromal tenascin C promotes epithelial to mesenchymal transition and correlates with distant metastasis in pancreatic cancer

The interaction between cancer cells and stromal components contributes to cancer invasion and metastasis in pancreatic ductal adenocarcinoma (PDAC). The present study investigated the role of the correlation between annexin II (ANX2) and stromal tenascin C (TNC) with the progression of PDAC. The functions of the expression ANX2 and TNC were assessed in in vitro experiments using mouse and human PDAC cells, and the clinical effect was analyzed using immunohistochemistry with surgically resected PDAC tissues. The effects on epithelial to mesenchymal transition (EMT), invasion, putative cancer stemness, and anoikis resistance were examined in vitro using murine precancerous pancreatic intraepithelial neoplasia (PanIN) cells and murine and human invasive PDAC cells with ANX2 knockdown using specific small interfering RNA (siRNA)s and recombinant TNC (rTNC). ANX2 was expressed at a high level in primary PanIN cells and invasive PDAC cells, compared with the levels in liver metastatic PDAC cells. In the ANX2-knockdown cells, there were fewer cells with a morphological mesenchymal appearance in three-dimensional culture and invasion was reduced compared with that in the control cells. Morphological change into the mesenchymal phenotype and invasion were enhanced by rTNC treatment in the control PDAC cells but not in the ANX2-knockdown cells. Pancreatosphere formation assays showed that ANX2 and TNC facilitated the maintenance of stem-like characters in PDAC cells. Furthermore, anoikis assays indicated that the interaction of ANX2-TNC contributed to anoikis resistance in PDAC cells. In the immunohistochemistry analyses, the group with a high expression of ANX2 and high stromal TNC was significantly correlated with distant metastasis, and was associated with hematogenous/peritoneal recurrence and poor outcomes following surgery in resected human primary PDAC tissues. In conclusion, the results demonstrated that ANX2 and stromal TNC regulated invasion in addition to stemness and anoikis resistance, which are crucial for metastasis in the progression of PDAC. These results indicate the potential of the ANX2-TNC axis as a therapeutic target for PDAC metastasis.