MUC5AC interactions with integrin β4 enhances the migration of lung cancer cells through FAK signaling

KRAS/PI3K axis driven GTF3C6 expression and promotes LUAD via FAK pathway

INTRODUCTION

Effective targeting drugs for KRAS mutation-mediated Lung Adenocarcinoma (LUAD) are currently are limited.

OBJECTIVES

Investigating and intervening in the downstream key target genes of KRAS is crucial for clinically managing KRAS mutant-driven LUAD. GTF3C6, a newly identified member of the general transcription factor III (GTF3) family, plays a role in the transcription of RNA polymerase III (pol III)-dependent genes. However, its involvement in cancer remains unexplored.

METHODS

This study examined the expression, roles, and potential molecular mechanisms of GTF3C6 in LUAD tissues, LSL-KrasG12D/+;LSL-p53-/- LUAD mouse models, and LUAD patients-derived organoid using Western blot, qRT-PCR, immunofluorescence, immunohistochemistry, and gene manipulation assays.

RESULTS

We present the first evidence that GTF3C6 is highly expressed in LUAD tissues, LSL-KrasG12D/+;LSL-p53-/- LUAD mouse models, and LUAD organoids, correlating with poor clinical prognosis. Furthermore, GTF3C6 was found to promote anchorage-independent proliferation, migration, and invasion of LUAD cells. Mechanistically, KRAS mutation drives GTF3C6 expression through the PI3K pathway, and GTF3C6 knockdown reverses the malignant phenotype of KRAS mutation-driven LUAD cells. Additionally, the FAK pathway emerged as a crucial downstream signaling pathway through which GTF3C6 mediates the malignant phenotype of LUAD. Finally, GTF3C6 knockdown suppresses LUAD organoid formation and inhibits tumor growth in vivo.

CONCLUSION

Our findings demonstrate that GTF3C6, driven by KRAS mutation, promotes LUAD development by regulating FAK phosphorylation, suggesting its potential as a biomarker and therapeutic target in KRAS mutant-driven LUAD.

Novel BRD4-p53 Inhibitor SDU-071 Suppresses Proliferation and Migration of MDA-MB-231 Triple-Negative Breast Cancer Cells

A promising alternative for cancer treatment involves targeted inhibition of the epigenetic regulator bromodomain-containing protein 4 (BRD4); however, available BRD4 inhibitors are constrained by their potency, oral bioavailability, and cytotoxicity. Herein, to overcome the drawback of the translational BRD4 inhibitors, we describe a novel BRD4-p53 inhibitor, SDU-071, which suppresses BRD4 interaction with the p53 tumor suppressor and its biological activity in MDA-MB-231 triple-negative breast cancer (TNBC) cells in vitro and in vivo. This novel small-molecule BRD4-p53 inhibitor suppresses cell proliferation, migration, and invasion by downregulating the expression of BRD4-targeted genes, such as c-Myc and Mucin 5AC, and inducing cell cycle arrest and apoptosis, as demonstrated in cultured MDA-MB-231 TNBC cells. Its antitumor activity is illustrated in an orthotopic mouse xenograft mammary tumor model. Overall, our results show that SDU-071 is a viable option for potentially treating TNBC as a new BRD4-p53 inhibitor.

Connectivity mapping-based identification of pharmacological inhibitor targeting HDAC6 in aggressive pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains highly lethal due to limited therapeutic options and expensive/burdensome drug discovery processes. Utilizing genomic-data-driven Connectivity Mapping (CMAP) to identify a drug closer to real-world PC targeting may improve pancreatic cancer (PC) patient outcomes. Initially, we mapped CMAP data to gene expression from 106 PC patients, identifying nine negatively connected drugs. These drugs were further narrowed down using a similar analysis for PC cell lines, human tumoroids, and patient-derived xenografts datasets, where ISOX emerged as the most potent agent to target PC. We used human and mouse syngeneic PC cells, human and mouse tumoroids, and in vivo mice to assess the ability of ISOX alone and in combination with 5FU to inhibit tumor growth. Global transcriptomic and pathway analysis of the ISOX-LINCS signature identified HDAC 6/cMyc as the target axis for ISOX. Specifically, we discovered that genetic and pharmacological targeting of HDAC 6 affected non-histone protein cMyc acetylation, leading to cMyc instability, thereby disrupting PC growth and metastasis by affecting cancer stemness. Finally, KrasG12D harboring tumoroids and mice responded effectively against ISOX and 5FU treatment by enhancing survival and controlling metastasis incidence. Overall, our data validate ISOX as a new drug to treat advanced PC patients without toxicity to normal cells. Our study supports the clinical utility of ISOX along with 5FU in future PC clinical trials.

Should we be screening for COPD? - looking through the lens of lung cancer screening

INTRODUCTION

In May 2022, the US Preventive Services Task Force published their recommendation against screening for chronic obstructive pulmonary disease (COPD) in asymptomatic adults. However, we argue the routine use of spirometry in both asymptomatic and symptomatic high-risk smokers has utility.

AREAS COVERED

We provide published and unpublished observations from a secondary analyses of the American College of Radiology Imaging Network (ACRIN), arm of the National Lung Screening Trial, including 18,463 high-risk current or former smokers who underwent pre-bronchodilator spirometry at baseline. According to history alone, 20% reported a prior diagnosis of 'COPD,' although only 11% (about one half), actually had airflow limitation (Diagnosed COPD) and 9% had Global Initiative for Obstructive Pulmonary Disease GOLD 0 Pre-COPD. Of the remaining 80% of 'asymptomatic' screening participants, 23% had airflow limitation (Screen-detected COPD) and 13% had preserved ratio impaired spirometry (PRISm). This means 45% of this high-risk cohort were reclassified by spirometry, and together with comorbid disease, identified subgroups where lung cancer screening efficacy could be optimized by between 2-6 fold.

EXPERT OPINION

Our preliminary findings suggest lung cancer screening outcomes vary according to 'new' COPD-related spirometric-defined subgroups and that screening spirometry, together with comorbid disease, identifies those for whom lung cancer screening is mostly beneficial or potentially harmful.

Differential Chemoproteomics Reveals MARK2/3 as Cell Migration-Relevant Targets of the ALK Inhibitor Brigatinib

Metastasis poses a major challenge in cancer management, including EML4-ALK-rearranged non-small cell lung cancer (NSCLC). As cell migration is a critical step during metastasis, we assessed the anti-migratory activities of several clinical ALK inhibitors in NSCLC cells and observed differential anti-migratory capabilities despite similar ALK inhibition, with brigatinib displaying superior anti-migratory effects over other ALK inhibitors. Applying an unbiased in situ mass spectrometry-based chemoproteomics approach, we determined the proteome-wide target profile of brigatinib in EML4-ALK+ NSCLC cells. Dose-dependent and cross-competitive chemoproteomics suggested MARK2 and MARK3 as relevant brigatinib kinase targets. Functional validation showed that combined pharmacological inhibition or genetic modulation of MARK2/3 inhibited cell migration. Consistently, brigatinib treatment induced inhibitory YAP1 phosphorylation downstream of MARK2/3. Collectively, our data suggest that brigatinib exhibits unusual cross-phenotype polypharmacology as, despite similar efficacy for inhibiting EML4-ALK-dependent cell proliferation as other ALK inhibitors, it more effectively prevented migration of NSCLC cells due to co-targeting of MARK2/3.

Integrins in cancer: Emerging mechanisms and therapeutic opportunities

Integrins are vital surface adhesion receptors that mediate the interactions between the extracellular matrix (ECM) and cells and are essential for cell migration and the maintenance of tissue homeostasis. Aberrant integrin activation promotes initial tumor formation, growth, and metastasis. Recently, many lines of evidence have indicated that integrins are highly expressed in numerous cancer types and have documented many functions of integrins in tumorigenesis. Thus, integrins have emerged as attractive targets for the development of cancer therapeutics. In this review, we discuss the underlying molecular mechanisms by which integrins contribute to most of the hallmarks of cancer. We focus on recent progress on integrin regulators, binding proteins, and downstream effectors. We highlight the role of integrins in the regulation of tumor metastasis, immune evasion, metabolic reprogramming, and other hallmarks of cancer. In addition, integrin-targeted immunotherapy and other integrin inhibitors that have been used in preclinical and clinical studies are summarized.

Patient-derived spheroids and patient-derived organoids simulate evolutions of lung cancer

Cancer cells harbor many genetic mutations and gene expression profiles different from normal cells. Patient-derived cancer cells (PDCC) are preferred materials in cancer study. We established patient-derived spheroids (PDSs) and patient-derived organoids (PDOs) from PDCCs isolated from the malignant pleural effusion in 8 patients. The morphologies suggested that PDSs may be a model of local cancer extensions, while PDOs may be a model of distant cancer metastases. The gene expression profiles differed between PDSs and PDOs: Gene sets related to inflammatory responses and EMT were antithetically regulated in PDSs or in PDOs. PDSs demonstrated an attenuation of the pathways that contribute to the enhancement of transforming growth factor beta (TGF-β) induced epithelial mesenchymal transition (EMT), while PDOs demonstrated an attenuation of it. Taken together, PDSs and PDOs have differences in both the interaction to the immune systems and to the stroma. PDSs and PDOs will provide a model system that enable intimate investigation of the behavior of cancer cells in the body.

Elevated PAF1-RAD52 axis confers chemoresistance to human cancers

Cisplatin- and gemcitabine-based chemotherapeutics represent a mainstay of cancer therapy for most solid tumors; however, resistance limits their curative potential. Here, we identify RNA polymerase II-associated factor 1 (PAF1) as a common driver of cisplatin and gemcitabine resistance in human cancers (ovarian, lung, and pancreas). Mechanistically, cisplatin- and gemcitabine-resistant cells show enhanced DNA repair, which is inhibited by PAF1 silencing. We demonstrate an increased interaction of PAF1 with RAD52 in resistant cells. Targeting the PAF1 and RAD52 axis combined with cisplatin or gemcitabine strongly diminishes the survival potential of resistant cells. Overall, this study shows clinical evidence that the expression of PAF1 contributes to chemotherapy resistance and worse clinical outcome for lethal cancers.

ITGB4 deficiency in airway epithelia enhances HDM-induced airway inflammation through hyperactivation of TLR4 signaling pathway

Airway epithelial cells (AECs) are the first cell barrier of the respiratory system against external stimuli that play a critical role in the development of asthma. It is known that AECs play a key role in asthma susceptibility and severity. ITGB4 is a downregulated adhesion molecule in the airway epithelia of asthma patients, which was involved in the exaggerated lung inflammation after allergy stimulation. Toll-like receptor 4 (TLR4) in AECs has also been shown to play a crucial role in the development of lung inflammation in asthma patients. However, the specific intrinsic regulatory mechanism of TLR4 in AECs are still obscure. In this article, we demonstrated that ITGB4 deficiency in AECs enhances HDM-induced airway inflammation through hyperactivation of the TLR4 signaling pathway, which is mediated by inhibition of FYN phosphorylation. Moreover, TLR4-antagonist treatment or blockade of FYN can inhibit or exaggerate lung inflammation in HDM-stressed ITGB4-deficient mice, separately. Together, these results demonstrated that ITGB4 deficiency in AECs enhances HDM-induced lung inflammatory response through the ITGB4-FYN-TLR4 axis, which may provide new therapeutic approaches for the management of lung inflammation in asthma.

Integrated analysis of necroptosis-related genes for evaluating immune infiltration and colon cancer prognosis

Background

Colon cancer (CC) is the second most common gastrointestinal malignancy. About one in five patients have already developed distant metastases at the time of initial diagnosis, and up to half of patients develop distant metastases from initial local disease, which leads to a poor prognosis for CC patients. Necroptosis plays a key role in promoting tumor growth in different tumors. The purpose of this study was to construct a prognostic model composed of necroptosis-related genes (NRGs) in CC.

Methods

The Cancer Genome Atlas was used to obtain information on clinical features and gene expression. Gene expression differential analysis, weighted gene co-expression network analysis, univariate Cox regression analysis and the least absolute shrinkage and selection operator regression algorithm were utilized to identify prognostic NRGs. Thereafter, a risk scoring model was established based on the NRGs. Biological processes and pathways were identified by gene ontology and gene set enrichment analysis (GSEA). Further, protein-protein interaction and ceRNA networks were constructed based on mRNA-miRNA-lncRNA. Finally, the effect of necroptosis related risk score on different degrees of immune cell infiltration was evaluated.

Results

CALB1, CHST13, and SLC4A4 were identified as NRGs of prognostic significance and were used to establish a risk scoring model. The time-dependent receiver operating characteristic curve analysis revealed that the model could well predict the 1-, 3-, and 5-year overall survival (OS). Further, GSEA suggested that the NRGs may participate in biological processes, such as the WNT pathway and JAK-Stat pathway. Eight key hub genes were identified, and a ceRNA regulatory network, which comprised 1 lncRNA, 5 miRNAs and 3 mRNAs, was constructed. Immune infiltration analysis revealed that the low-risk group had significantly higher immune-related scores than the high-risk group. A nomogram of the model was constructed based on the risk score, necroptosis, and the clinicopathological features (age and TNM stage). The calibration curves implied that the model was effective at predicting the 1-, 3-, and 5-year OS of CC.

Conclusion

Our NRG-based prognostic model can assist in the evaluation of CC prognosis and the identification of therapeutic targets for CC.

Muc16 depletion diminishes KRAS-induced tumorigenesis and metastasis by altering tumor microenvironment factors in pancreatic ductal adenocarcinoma

MUC16, membrane-bound mucin, plays an oncogenic role in pancreatic ductal adenocarcinoma (PDAC). However, the pathological role of MUC16 in the PDAC progression, tumor microenvironment, and metastasis in cooperation with KrasG12D and Trp53R172H mutations remains unknown. Deletion of Muc16 with activating mutations KrasG12D/+ and Trp53R172H/+ in mice significantly decreased progression and prolonged overall survival in KrasG12D/+; Trp53R172H/+; Pdx-1-Cre; Muc16-/- (KPCM) and KrasG12D/+; Pdx-1-Cre; Muc16-/- (KCM), as compared to KrasG12D/+; Trp53R172H/+; Pdx-1-Cre (KPC) and KrasG12D/+; Pdx-1-Cre (KC) mice, respectively. Muc16 knockout pancreatic tumor (KPCM) displays decreased tumor microenvironment factors and significantly reduced incidence of liver and lung metastasis compared to KPC. Furthermore, in silico data analysis showed a positive correlation of MUC16 with activated stroma and metastasis-associated genes. KPCM mouse syngeneic cells had significantly lower metastatic and endothelial cell binding abilities than KPC cells. Similarly, KPCM organoids significantly decreased the growth rate compared to KPC organoids. Interestingly, RNA-seq data revealed that the cytoskeletal proteins Actg2, Myh11, and Pdlim3 were downregulated in KPCM tumors. Further knockdown of these genes showed reduced metastatic potential. Overall, our results demonstrate that Muc16 alters the tumor microenvironment factors during pancreatic cancer progression and metastasis by changing the expression of Actg2, Myh11, and Pdlim3 genes.

Laminin-bound integrin α6β4 promotes non-small cell lung cancer progression via the activation of YAP/TAZ signaling pathway

Laminin is an extracellular matrix multidomain trimeric glycoprotein, that has a potential role in tumor progression. Here, we studied the effects of non-small cell lung cancer (NSCLC) cells interaction on laminin and explored the underlying mechanism of laminin associated NSCLC progression. Culture of A549 and NCI-1299 cells on 2D collagen gels (containing laminin) significantly promoted the proliferative and tumorigenic characteristics, as well as cell invasion of tumor cells in vitro. Consistently, comparing the clinical NSCLC tumor tissues, a poor overall survival was observed in patients with high laminin expression. Mechanistically, the expression of integrin α6β4 was required for the pro-tumor effects of laminin. Meanwhile, we showed that the downstream signaling of integrin α6β4, involved the focal adhesion kinase (FAK)/Yes-Associated Protein (YAP)/TAZ signaling pathway. The activation of FAK/YAP/TAZ signaling pathway induced by laminin was validated in tumor tissues from NSCLC patients. Suppression of integrin α6β4/FAK/YAP/TAZ signaling pathway efficiently suppressed the laminin-induced tumor growth, and strengthened the anticancer effects of chemotherapy, describing a novel target for NSCLC treatment.

Expression of Mucin Family Proteins in Non-Small-Cell Lung Cancer and its Role in Evaluation of Prognosis

Lung cancer is still the major contributor to cancer-related mortality. Over 85% of patients suffer from non-small-cell lung cancer (NSCLC). Mucins (MUCs) are large glycoproteins secreted or membrane-bound produced by epithelial cells in normal and malignant tissues. They are the major components of the mucous gel that covers the surface of the respiratory epithelium. Certain MUCs have been used or proposed to act as biomarkers for lung cancer. Nevertheless, the expression, messenger ribonucleic acid (mRNA) levels, and the prognostic value of MUCs in NSCLC are yet to be investigated systematically. In this research, the biological information of MUC proteins in patients with NSCLC was examined using a series of databases. The results based on gene expression profiling interactive analysis (GEPIA) illustrated that the expression of MUC3A, MUC4, MUC5B, MUC13, MUC16, and MUC21 mRNAs was remarkably upmodulated in lung adenocarcinoma (LUAD) patients, whereas the MUC1 expression was downregulated in lung squamous cell carcinoma (LUSC) patients. Kaplan–Meier plotter (KM Plotter) analysis revealed that elevated mRNA expression levels of MUC3A and MUC16 were linked to unfavourable overall survival (OS) in NSCLC, while increased mRNA expression of MUC1 and MUC15 was linked to good OS, especially in LUAD patients. In addition, differential expression of MUC1, MUC3A/3B, MUC8, MUC12, MUC15, and MUC16 mRNA was linked to the prognoses of NSCLC patients with varied clinical-pathological subtypes. Genetic alterations of MUCs in NSCLC primarily involved mutations, fusion, amplification, deep deletion, and multiple alterations according to cancer genomics (cBioPortal). Therefore, we propose that combinations of MUC proteins can act as prognostic biomarkers and demonstrate the therapeutic potential for NSCLC-related therapy.

Laminin-integrin a6b4 interaction activates notch signaling to facilitate bladder cancer development

Background

Laminins are high-molecular weight (400 ~ 900 kDa) proteins in extracellular matrix, which serve as major component of the basal lamina, and play a crucial role in promoting tumor cell migration. This study aimed at characterizing the role of laminin in promoting cancer development, and elucidating the mechanism of tumor progression driven by laminin-Notch signaling in bladder cancer.

Methods

2D collagen/laminin culture system was established and CCK-8/transwell assay was conducted to evaluate the proliferation/migration ability of Biu-87 and MB49 cells cultured on 2D gels. Activation of integrins-Notch1 signaling was determined by western blotting. Orthotopic bladder cancer mice model was established to assess the therapeutic effects of Notch inhibitor.

Results

Our study demonstrated that extracellular laminin can trigger tumor cell proliferation/migration through integrin α6β4/Notch1 signaling in bladder cancer. Inhibition of Telomere repeat-binding factor 3 (TRB3)/Jagged Canonical Notch Ligand 1 (JAG1) signaling suppressed Notch signals activation induced by laminin-integrin axis. In MB49 orthotopic bladder cancer mice model, Notch inhibitor SAHM1 efficiently improved tumor suppressive effects of chemotherapy and prolonged survival time of tumor-bearing mice.

Conclusion

In conclusion, we show that, in bladder cancer, extracellular laminin induced the activation of Notch pathway through integrin α6β4/TRB3/JAG3, and disclosed a novel role of laminin in bladder cancer cells proliferation or migration.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09645-7.

Tspan9 Induces EMT and Promotes Osteosarcoma Metastasis via Activating FAK-Ras-ERK1/2 Pathway

Object

At present, there are few effective treatment options available to patients suffering from osteosarcoma (OS). Clarifying the signaling pathways that govern OS oncogenesis may highlight novel approaches to treating this deadly form of cancer. Recent experimental evidence suggests that the transmembrane protein tetraspanin-9 (Tspan9) plays a role in tumor development. This study was thus formulated to assess the molecular role of Tspan9 as a regulator of OS cell metastasis.

Methods

Gene expression in OS cell lines was evaluated via qRT-PCR, while CCK-8, colony formation, Transwell, and wound healing assays were used to explore the in vitro proliferative, invasive, and migratory activities of OS cells. The relationship between Tspan9 and in vivo OS cell metastasis was assessed by injecting these cells into the tail vein of nude mice. Interactions between the Tspan9 and integrin β1 proteins were explored through mass spectrometric and co-immunoprecipitation, and Western blotting to assess the functional mechanisms whereby Tspan9 shapes OS pathogenesis.

Results

Both primary OS tumors and OS cell lines commonly exhibited Tspan9 upregulation, and the knockdown of this tetraspanin suppressed the migration, invasion, and epithelial-mesenchymal transition (EMT) activity in OS cells, whereas Tspan9 overexpression resulted in opposite phenotypes. Tumor lung metastasis were significantly impaired in mice implanted with HOS cells in which Tspan9 was downregulated as compared to mice implanted with control HOS cells. Tspan9 was also found to interact with β1 integrin and to contribute to OS metastasis via the amplification of integrin-mediated downstream FAK/Ras/ERK1/2 signaling pathway.

Conclusion

These data suggest that Tspan9 can serve as a promising therapeutic target in OS.

Spatial Proteomic Analysis of Isogenic Metastatic Colorectal Cancer Cells Reveals Key Dysregulated Proteins Associated with Lymph Node, Liver, and Lung Metastasis

Metastasis is the primary cause of colorectal cancer (CRC) death. The liver and lung, besides adjacent lymph nodes, are the most common sites of metastasis. Here, we aimed to study the lymph nodes, liver, and lung CRC metastasis by quantitative spatial proteomics analysis using CRC cell-based models that recapitulate these metastases. The isogenic KM12 cell system composed of the non-metastatic KM12C cells, liver metastatic KM12SM cells, and liver and lung metastatic KM12L4a cells, and the isogenic non-metastatic SW480 and lymph nodes metastatic SW620 cells, were used. Cells were fractionated to study by proteomics five subcellular fractions corresponding to cytoplasm, membrane, nucleus, chromatin-bound proteins, and cytoskeletal proteins, and the secretome. Trypsin digested extracts were labeled with TMT 11-plex and fractionated prior to proteomics analysis on a Q Exactive. We provide data on protein abundance and localization of 4710 proteins in their different subcellular fractions, depicting dysregulation of proteins in abundance and/or localization in the most common sites of CRC metastasis. After bioinformatics, alterations in abundance and localization for selected proteins from diverse subcellular localizations were validated via WB, IF, IHC, and ELISA using CRC cells, patient tissues, and plasma samples. Results supported the relevance of the proteomics results in an actual CRC scenario. It was particularly relevant that the measurement of GLG1 in plasma showed diagnostic ability of advanced stages of the disease, and that the mislocalization of MUC5AC and BAIAP2 in the nucleus and membrane, respectively, was significantly associated with poor prognosis of CRC patients. Our results demonstrate that the analysis of cell extracts dilutes protein alterations in abundance in specific localizations that might only be observed studying specific subcellular fractions, as here observed for BAIAP2, GLG1, PHYHIPL, TNFRSF10A, or CDKN2AIP, which are interesting proteins that should be further analyzed in CRC metastasis.

ITGB4 deficiency induces mucus hypersecretion by upregulating MUC5AC in RSV-infected airway epithelial cells

Respiratory syncytial virus (RSV) infection is the main cause of bronchiolitis in children. Excessive mucus secretion is one of the primary symbols in RSV related lower respiratory tract infections (RSV-related LRTI), which is closely associated with the occurrence and development of asthma in later life. Integrin β4 (ITGB4) is down-regulated in the airway epithelial cells (AECs) of asthma patients which plays a critical role in the pathogenesis of asthma. However, whether ITGB4 is involved in the pathological processes of RSV infection remains unclear. In this study, we found that decreased expression of ITGB4 was negatively correlated with the level of MUC5AC in childhood AECs following RSV infection. Moreover, ITGB4 deficiency led to mucus hypersecretion and MUC5AC overexpression in the small airway of RSV-infected mice. MUC5AC expression was upregulated by ITGB4 in HBE cells through EGFR, ERK and c-Jun pathways. EGFR inhibitors treatment inhibited mucus hypersecretion and MUC5AC overexpression in ITGB4-deficient mice after RSV infection. Together, these results demonstrated that epithelial ITGB4 deficiency induces mucus hypersecretion by upregulating the expression of MUC5AC through EGFR/ERK/c-Jun pathway, which further associated with RSV-related LRTI.

Mucin 5AC expression is common but unrelated to tumor progression in pancreatic adenocarcinoma

Introduction: Mucin 5AC (MUC5AC) belongs to the family of secreted gel-forming mucins. It is physiologically expressed in some normal mucin producing epithelial cells but also in pancreatic, ovarian, and colon cancer cells. The role of MUC5AC expression in cancer is not fully understood. This study was designed to explore the role of MUC5AC for pancreatic cancer progression, its association to microsatellite instability, and its diagnostic utility. Methods: Mucin 5AC expression was studied immunohistochemically in a tissue microarray (TMA) from 532 pancreatic cancers, 61 cancers of the ampulla Vateri, six acinar cell carcinomas and 12 large sections of pancreatitis. Results: Mucin 5AC staining was interpretable in 476 of 599 (79%) arrayed cancers. Staining was completely absent in normal pancreas and pancreatitis, but frequent in pancreatic cancer. Membranous and cytoplasmic MUC5AC expression was most common in pancreatic adenocarcinomas (71% of 423), followed by carcinomas of the ampulla Vateri (43% of 47), and absent in six acinar cell carcinomas. Mucin 5AC expression was unrelated to tumor phenotype (tumor stage, tumor grade, lymph node, and distant metastasis), and microsatellite instability in ductal adenocarcinomas and carcinomas of the ampulla Vateri. Conclusion: Our study indicates that MUC5AC is an excellent biomarker for pancreatic cancer diagnosis, especially to support the sometimes-difficult diagnosis on small biopsies. Mucin 5AC expression is unrelated to pancreatic cancer aggressiveness.

Low Tumor Infiltrating Mast Cell Density Reveals Prognostic Benefit in Cervical Carcinoma

Objectives: Research on the role of mast cells (MCs) in cervical tumor immunity is more limited. Therefore, our study aimed to evaluate the prognostic value of MCs and their correlation with the immune microenvironment of cervical carcinoma (CC). Methods: The Cancer Genome Atlas (TCGA) data was utilized to obtain the degree of immune infiltration of MCs in CC. Meanwhile, this study retrospectively collected patient clinical characteristic data and tissue specimens to further verify the relevant conclusions. Mast cell density (MCD) was measured by the CIBERSORT algorithm in TCGA data and immunohistochemical staining of tryptase in CC tissues. Finally, differentially expressed genes (DEGs) of TCGA data were performed using "limma" packages and key gene modules were identified using the MCODE application in Cytoscape. Results: The results showed MCs were diffusely distributed in CC tissues. Moreover, we found that low tumor-infiltrating MCD was beneficial for overall survival (OS) in the TCGA cohort. Consistent conclusions were also obtained in a clinical cohort. In addition, a total of 305 DEGs were analyzed between the high tumor-infiltrating MCD and low tumor-infiltrating MCD group. Seven key modules, a total of 34 genes, were screened through the MCODE plug-in, which was mainly related to inflammatory response and immune response and closely correlated with cytokines including CSF2, CCL20, IL1A, IL1B, and CXCL8. Conclusion: In short, high tumor-infiltration MCs in CC tissue was associated with worse OS in patients. Furthermore, MCs were closely related to cytokines in the tumor microenvironment, suggesting that they collectively played a role in the immune response of the tumor. Therefore, MCD may be a potential prognostic indicator and immunotherapy target of CC.

Role of caveolin-1 as a biomarker for radiation resistance and tumor aggression in lung cancer

Radiation therapy plays a major role in the treatment of lung cancer patients. However, cancer cells develop resistance to radiation. Tumor radioresistance is a complex multifactorial mechanism which may be dependent on DNA damage and repair, hypoxic conditions inside tumor microenvironment, and the clonal selection of radioresistant cells from the heterogeneous tumor site, and it is a major cause of treatment failure in non-small cell lung cancer (NSCLC). In the present investigation caveolin-1 (CAV-1) has been observed to be highly expressed in radiation resistant A549 lung cancer cells. CRISPR-Cas9 knockout of CAV-1 reverted the cells to a radio sensitive phenotype. In addition, CAV-1 overexpression in parental A549 cells, led to radiation resistance. Further, gene expression analysis of A549 parental, radiation resistant, and caveolin-1 overexpressed cells, exhibited overexpression of DNA repair genes RAD51B, RAD18, SOX2 cancer stem cell marker, MMPs, mucins and cytoskeleton proteins in resistant and caveolin-1 over expressed A549 cells, as compared to parental A549 cells. Bioinformatic analysis shows upregulation of BRCA1, Nuclear Excision DNA repair, TGFB and JAK/STAT signaling pathways in radioresistant and caveolin-1 overexpressed cells, which may functionally mediate radiation resistance. Immunohistochemistry data demonstrated heterogeneous expression of CAV-1 gene in human lung cancer tissues, which was analogous to its enhanced expression in human lung cancer cell line model and mouse orthotopic xenograft lung cancer model. Also, TCGA PanCancer clinical studies have demonstrated amplification, deletions and missense mutation in CAV-1 gene in lung cancer patients, and that CAV-1 alteration has been linked to poor prognosis, and poor survival in lung cancer patients. Interestingly, we have also optimized ELISA assay to measure caveolin-1 protein in the blood of A549 radiation resistant human xenograft preclinical mouse model and discovered higher level of caveolin-1 (950 pg/ml) in tumor bearing animals treated with radiation, as compared to xenograft with radiosensitive lung cancer cells (450 pg/ml). Thus, we conclude that caveolin-1 is involved in radio-resistance and contributes to tumor aggression, and it has potential to be used as prognostic biomarker for radiation treatment response, and tumor progression for precision medicine in lung cancer patients.

MUC5AC Expression in Various Tumor Types and Nonneoplastic Tissue: A Tissue Microarray Study on 10 399 Tissue Samples

Background: Mucin 5AC (MUC5AC) belongs to the glycoprotein family of secreted gel-forming mucins and is physiologically expressed in some epithelial cells. Studies have shown that MUC5AC is also expressed in several cancer types suggesting a potential utility for the distinction of tumor types and subtypes. Methods: To systematically determine MUC5AC expression in normal and cancerous tissues, a tissue microarray containing 10 399 samples from 111 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. Results: MUC5AC was expressed in normal mucus-producing cells of various organs. At least weak MUC5AC positivity was seen in 44 of 111 (40%) tumor entities. Of these 44 tumor entities, 28 included also tumors with strong positivity. MUC5AC immunostaining was most commonly seen in esophageal adenocarcinoma (72%), colon adenoma (62%), ductal adenocarcinoma of the pancreas (64%), mucinous carcinoma of the ovary (46%), diffuse gastric adenocarcinoma (44%), pancreatic ampullary adenocarcinoma (41%), intestinal gastric adenocarcinoma (39%), and bronchioloalveolar carcinoma (33%). Clinically relevant tumors with complete or almost complete absence of MUC5AC staining included small cell carcinoma of the lung (0% of 17), clear cell renal cell carcinoma (0% of 507), papillary thyroid carcinoma (0% of 359), breast cancer (2% of 1097), prostate cancer (2% of 228), soft tissue tumors (0.1% of 968), and hematological neoplasias (0% of 111). Conclusion: The highly standardized analysis of a broad range of cancers identified a ranking order of tumors according to their relative prevalence of MUC5AC expression.

Regulation of hemidesmosome dynamics and cell signaling by integrin α6β4

Hemidesmosomes (HDs) are specialized multiprotein complexes that connect the keratin cytoskeleton of epithelial cells to the extracellular matrix (ECM). In the skin, these complexes provide stable adhesion of basal keratinocytes to the underlying basement membrane. Integrin α6β4 is a receptor for laminins and plays a vital role in mediating cell adhesion by initiating the assembly of HDs. In addition, α6β4 has been implicated in signal transduction events that regulate diverse cellular processes, including proliferation and survival. In this Review, we detail the role of α6β4 in HD assembly and beyond, and we discuss the molecular mechanisms that regulate its function.

Integrin β1 subunit regulates cellular and secreted MUC5AC and MUC5B production in NCI-H292 human lung epithelial cells

The surface of the human respiratory tract is covered with a mucus layer containing mucin 5AC (MUC5AC) and mucin 5B (MUC5B) as the main components. This layer contributes to biological defense by eliminating irritants, but excessive MUC5AC secretion by the airway epithelial cells exacerbates asthma. Therefore, regulating mucin production is important for asthma treatment. In this study, the effects of integrin β1 subunit on MUC5AC and MUC5B production were examined in NCI–H292 human lung cancer epithelial cells. When integrin β1 was overexpressed, cellular and secreted MUC5AC levels were decreased, whereas cellular MUC5B production was increased. Conversely, integrin β1 depletion using siRNA increased cellular and secreted MUC5AC production, but decreased cellular MUC5B production. Further, the activity of extracellular signal-regulated kinase (ERK), which promotes MUC5AC production, was decreased by integrin β1 overexpression and increased by its depletion. These results suggest that integrin β1 suppresses MUC5AC production and promotes MUC5B production by downregulating ERK.

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We studied the regulation of MUC5AC and MUC5B production by integrin β1 subunit.

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Integrin β1 overexpression reduced MUC5AC, but increased MUC5B levels.

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Integrin β1 depletion increased MUC5AC production and ROS level, but decreased MUC5B production.

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Integrin β1 overexpression decreased ERK activity in NCI–H292 airway cells.

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Integrin β1 downregulates ERK to suppress MUC5AC & promote MUC5B production.

Integrin β4 as a Potential Diagnostic and Therapeutic Tumor Marker

Integrin β4 (ITGβ4) is a class of transmembrane adhesion molecules composed of hemidesmosomes (HDs). Its unique long intracellular domain provides intricate signal transduction functions. These signal transduction effects are especially prominent in tumors. Many recent studies have shown that integrin β4 is differentially expressed in various tumors, and it plays a vital role in tumor invasion, proliferation, epithelial–mesenchymal transition, and angiogenesis. Therefore, we categorize the research related to integrin β4, starting from its structure and function in tumor tissues, and provide a basic description. Based on its structure and function, we believe that integrin β4 can be used as a tumor marker. In clinical practice, it is described as a diagnostic marker for the targeted treatment of cancer and will be helpful in the clinical diagnosis and treatment of tumors.

Resveratrol inhibits MUC5AC expression by regulating SPDEF in lung cancer cells

BACKGROUND

MUC5AC was recently identified to play important roles in the proliferation and metastasis of malignant mucinous lung tumor cells. Resveratrol (Res), a natural compound with anticancer effects in lung cancer cells, has been reported to inhibit mucin production in airway epithelial cells. This study aimed to investigate the inhibitory effect of Res on MUC5AC expression in lung mucinous adenocarcinoma cells and the potential mechanisms.

METHODS

Mucus-producing A549 human lung carcinoma cells were used to test the effects of Res on SPDEF and MUC5AC expression. Gene and protein expression was assessed by real-time quantitative PCR (qPCR), immunofluorescence and western blotting assays. SPDEF lentivirus was used to upregulate SPDEF expression levels in mucus-producing A549 human lung carcinoma cells. Cell proliferation was assessed by Cell Counting Kit-8 (CCK-8) assay.

RESULTS

Res decreased MUC5AC expression in an SPDEF-dependent manner in mucus-producing A549 human lung carcinoma cells, and this change was accompanied by decreased ERK expression and AKT pathway activation. Moreover, SPDEF was found to be overexpressed in lung adenocarcinoma (LUAD), especially in mucinous adenocarcinoma. In-vitro functional assays showed that overexpression of SPDEF reduced the chemosensitivity of A549 cells to cisplatin (DDP). In addition, Res treatment increased A549 cell chemosensitivity to DDP by inhibiting the SPDEF-MUC5AC axis.

CONCLUSION

Our results indicate that the SPDEF-MUC5AC axis is associated with DDP sensitivity, and that Res decreases SPDEF and MUC5AC expression by inhibiting ERK and AKT signaling in A549 cells, which provides a potential pharmacotherapy for the prevention and therapeutic management of mucinous adenocarcinoma.

MUC5AC expression is linked to mucinous/endometroid subtype, absence of nodal metastasis and mismatch repair deficiency in ovarian cancer

Mucin 5AC (MUC5AC) is a secreted gel-forming mucin which is expressed by mucus producing cells of several organs but can also be found in cancer cells of the ovary, pancreas, and gastrointestinal tract. This study aimed to characterize the expression of MUC5AC and its potential prognostic implications in different ovarian cancer subtypes. MUC5AC expression was analyzed by immunohistochemistry on a tissue microarray containing 603 ovarian cancers. MUC5AC was commonly expressed in mucinous (27/36; 75%) and endometrioid (12/39; 31%) carcinomas, whereas malignant mixed Mullerian tumors (2/27; 7%), high-grade serous (20/373; 5%) and clear cell carcinomas (1/28; 4%) were only rarely MUC5AC positive and also showed lower expression levels. MUC5AC positive endometroid carcinomas and high-grade serous carcinomas lacked lymph node metastases (p = 0.0495 and p = 0.0216) suggesting a more favorable prognosis. Deficient mismatch repair (dMMR), associated with a favorable prognosis in different cancer types, was found in 4/39 (10%) MUC5AC positive cancers but in only 5/375 (1%) of MUC5AC negative cancers (p = 0.0052). In subgroup analyses MUC5AC positive endometroid carcinomas more frequently showed dMMR (4/10; 40%) as opposed to MUC5AC negative endometroid carcinomas (3/23; 13%; p = 0.0932). In summary, the results of our study show that MUC5AC expression is associated with mucinous and endometrioid ovarian carcinomas, lack of nodal metastases and dMMR. MUC5AC expressing ovarian cancers should be evaluated for dMMR.

Inhibition of Cancer Cell Adhesion, Migration and Proliferation by a Bispecific Antibody that Targets two Distinct Epitopes on αv Integrins

Members of the αv family of integrins regulate activation of transforming growth factor beta (TGFβ) and are directly involved in pro-tumorigenic phenotypes. Thus, αv integrins may be therapeutic targets for fibrosis and cancer, yet the isolation of selective inhibitors is currently a challenge. We generated synthetic antibodies selective for αv integrins by phage display selections on cell lines that displayed integrin heterodimers. We identified antibodies that targeted two distinct epitopes on cell-surface αv integrins and partially inhibited cell adhesion mediated by interactions between integrins and the latency-associated peptide, part of the pro-form of TGFβ. Using the isolated antibody paratope sequences we engineered a bispecific antibody capable of binding to both epitopes simultaneously; this antibody potently and completely inhibited cell adhesion mediated by integrins αvβ1, αvβ3 and αvβ5. In addition, the bispecific antibody inhibited proliferation and migration of lung carcinoma lines, where the highest and lowest potencies observed correlated with integrin-αv cell surface expression levels. Taken together, our results demonstrate that phage display selections with live cells can yield high quality anti-integrin antibodies, which we used as biparatopic building blocks to construct a bispecific antibody that strongly inhibited integrin function and may be a therapeutic candidate for cancer and fibrosis.

ST6GalNAc-I promotes lung cancer metastasis by altering MUC5AC sialylation

Lung cancer (LC) is the leading cause of cancer-related mortality. However, the molecular mechanisms associated with the development of metastasis are poorly understood. Understanding the biology of LC metastasis is critical to unveil the molecular mechanisms for designing targeted therapies. We developed two genetically engineered LC mouse models Kras^G12D/+ ; Trp53^R172H/+ ; Ad-Cre (KPA) and Kras^G12D/+ ; Ad-Cre (KA). Survival analysis showed significantly (P = 0.0049) shorter survival in KPA tumor-bearing mice as compared to KA, suggesting the aggressiveness of the model. Our transcriptomic data showed high expression of N-acetylgalactosaminide alpha-2, 6-sialyltransferase 1 (St6galnac-I) in KPA compared to KA tumors. ST6GalNAc-I is an O-glycosyltransferase, which catalyzes the addition of sialic acid to the initiating GalNAc residues forming sialyl Tn (STn) on glycoproteins, such as mucins. Ectopic expression of species-specific p53 mutants in the syngeneic mouse and human LC cells led to increased cell migration and high expression of ST6GalNAc-I, STn, and MUC5AC. Immunoprecipitation of MUC5AC in the ectopically expressing p53^R175H cells exhibited higher affinity toward STn. In addition, ST6GalNAc-I knockout (KO) cells also showed decreased migration, possibly due to reduced glycosylation of MUC5AC as observed by low STn on the glycoprotein. Interestingly, ST6GalNAc-I KO cells injected mice developed less liver metastasis (P = 0.01) compared to controls, while colocalization of MUC5AC and STn was observed in the liver metastatic tissues of control mice. Collectively, our findings support the hypothesis that mutant p53^R175H mediates ST6GalNAc-I expression, leading to the sialyation of MUC5AC, and thus contribute to LC liver metastasis.

Differential MUC22 expression by epigenetic alterations in human lung squamous cell carcinoma and adenocarcinoma

Disruption in mucins (MUCs) is involved in cancer development and metastasis and is thus used as a biomarker. Non‑small cell lung carcinoma (NSCLC) is characterized by heterogeneous genetic and epigenetic alterations. Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are the two primary subtypes of NSCLC that require different therapeutic interventions. Here, we report distinct expression and epigenetic alterations in mucin 22 (MUC22), a new MUC family member, in LUSC vs. LUAD. In lung cancer cell lines and tissues, MUC22 was downregulated in LUSC (MUC22^Low) but upregulated in LUAD (MUC22^High) with co‑expression of MUC21. The aberrant expression of MUC22 was inversely correlated with its promoter hypermethylation in LUSC and hypomethylation in LUAD cells and tissues, respectively. Decreased MUC22 expression in NSCLC cell lines was restored upon treatment with epigenetic modifiers 5‑aza‑2'‑deoxycytidine (5‑Aza) or trichostatin A (TSA), accompanied by reduction in global protein level of histone deacetylase 1 (HDAC1) but increased enrichment of histone H3 lysine 9 acetylation (H3K9ac) specifically in the MUC22 promoter in the SK‑MES‑1 cell line. MUC22 knockdown increased the growth and motility of lung cancer cells and an immortalized human bronchial epithelial BEAS‑2B cell line via NF‑κB activation. Clinically, MUC22^Low in LUSC and MUC22^High in LUAD were shown to be indicators of unfavorable overall survival for patients with early cancer stages. Our study reveals that changes in MUC22 expression due to epigenetic alterations in NSCLC may have important biological significance and prognostic potential in LUSC when compared to LUAD. Thus, MUC22 expression and epigenetic alterations may be used for molecular subtyping of NSCLC in precision medicine.

Mucins reprogram stemness, metabolism and promote chemoresistance during cancer progression

Mucins are high-molecular-weight glycoproteins dysregulated in aggressive cancers. The role of mucins in disease progression, tumor proliferation, and chemotherapy resistance has been studied extensively. This article provides a comprehensive review of mucin's function as a physical barrier and the implication of mucin overexpression in impeded drug delivery to solid tumors. Mucins regulate the epithelial to mesenchymal transition (EMT) of cancer cells via several canonical and non-canonical oncogenic signaling pathways. Furthermore, mucins play an extensive role in enriching and maintaining the cancer stem cell (CSC) population, thereby sustaining the self-renewing and chemoresistant cellular pool in the bulk tumor. It has recently been demonstrated that mucins regulate the metabolic reprogramming during oncogenesis and cancer progression, which account for tumor cell survival, proliferation, and drug-resistance. This review article focuses on delineating mucin's role in oncogenic signaling and aberrant regulation of gene expressions, culminating in CSC maintenance, metabolic rewiring, and development of chemoresistance, tumor progression, and metastasis.

MUC1 and MUC5AC implication in Tunisian colorectal cancer patients

Background/aim

Mucins, such as MUC1 and MUC5AC, are known for their protective and moisturizing role in intestinal epithelium. Their expression is tightly controlled given their essential role in normal tissue homeostasis, whereas their deregulation leads to chronic inflammation, and even cancer. This study aimed to assess the expression profiles of MUC1 and MUC5AC and their implications in colorectal carcinogenesis.

Materials and methods

A retrospective study of 202 patients who underwent colorectal cancer (CRC) surgery was conducted. The expression of MUC1 and MUC5AC was investigated by immunohistochemistry and reverse-transcription polymerase chain reaction (RT-PCR). Statistical analysis of mucin expression pattern, as well as the clinicopathological criteria of the patients, was performed using the chi-square test, survival curves were plotted using the Kaplan—Meier product-limit method, and differences between the survival curves were tested using the log-rank test.

Results

The expression of both mucins was abnormally high in the tumor tissues for both mRNA and protein. MUC1 expression was correlated with advanced cancer stages and lymph node metastases for both the mRNA (P < 0.016 and P < 0.002, respectively) and protein level (P < 0.006 and P < 0.001, respectively). However, MUC5AC expression did not pinpoint any significant association between the clinicopathological criteria, but patients who expressed MUC5AC showed an increase in overall survival (P < 0.009).

Conclusion

The expression of MUC1 might be a poor prognostic biomarker in CRC and could play a role in tumor transformation and metastasis. However, MUC5AC expression might be a good prognostic in the Tunisian cohort.

Unraveling mucin domains in cancer and metastasis: when protectors become predators

A dynamic mucosal layer shields the epithelial cells lining the body cavities and is made up of high molecular weight, heavily glycosylated, multidomain proteins called mucins. Mucins, broadly grouped into transmembrane and secreted mucins, are the first responders to any mechanical or chemical insult to the epithelia and help maintain tissue homeostasis. However, their intrinsic properties to protect and repair the epithelia are exploited during oncogenic processes, where mucins are metamorphosed to aid the tumor cells in their malignant journey. Diverse domains, like the variable number tandem repeats (VNTR), sea urchin sperm protein enterokinase and agrin (SEA), adhesion-associated domain (AMOP), nidogen-like domain (NIDO), epidermal growth factor-like domain (EGF), and von Willebrand factor type D domain (vWD) on mucins, including MUC1, MUC4, MUC5AC, MUC5B, and MUC16, have been shown to facilitate cell-to-cell and cell-to-matrix interactions, and cell-autonomous signaling to promote tumorigenesis and distant dissemination of tumor cells. Several obstacles have limited the study of mucins, including technical difficulties in working with these huge glycoproteins, the dearth of scientific tools, and lack of animal models; thus, the tissue-dependent and domain-specific roles of mucins during mucosal protection, chronic inflammation, tumorigenesis, and hematological dissemination of malignant cells are still unclear. Future studies should try to integrate information on the rheological, molecular, and biological characteristics of mucins to comprehensively delineate their pathophysiological role and evaluate their suitability as targets in future diagnostic and therapeutic strategies.

Extracellular vesicles from young women's breast cancer patients drive increased invasion of non-malignant cells via the Focal Adhesion Kinase pathway: a proteomic approach

Background

Extracellular vesicles (EVs) are small membrane particles that contribute to cancer progression and metastases by transporting biologically significant proteins and nucleic acids. They may also serve as biomarkers of various disease states or important therapeutic targets. Breast cancer EVs have the potential to change the behavior of other cells in their microenvironment. However, the proteomic content of EVs isolated from young women’s breast cancer patients and the mechanisms underlying the influence of EVs on tumor cell behavior have not yet been reported.

Methods

In our current translational studies, we compared the proteomic content of EVs isolated from invasive breast cancer cell lines and plasma samples from young women’s breast cancer (YWBC) patients and age-matched healthy donors using mass spectrometry. We analyzed the functionality of EVs in two dimensional tumor cell invasion assays and the gene expression changes in tumor cells after incubation with EVs.

Results

We found that treatment with EVs from both invasive breast cancer cell lines and plasma of YWBC patients altered the invasive properties of non-invasive breast cancer cells. Proteomics identified differences between EVs from YWBC patients and healthy donors that correlated with their altered function. Further, we identified gene expression changes in non-invasive breast cancer cells after treatment with EVs that implicate the Focal Adhesion Kinase (FAK) signaling pathway as a potential targetable pathway affected by breast cancer-derived EVs.

Conclusions

Our results suggest that the proteome of EVs from breast cancer patients reflects their functionality in tumor motility assays and may help elucidate the role of EVs in breast cancer progression.

RNA Polymerase II-Associated Factor 1 Regulates Stem Cell Features of Pancreatic Cancer Cells, Independently of the PAF1 Complex, via Interactions With PHF5A and DDX3

BACKGROUND & AIMS

It is not clear how pancreatic cancer stem cells (CSCs) are regulated, resulting in ineffective treatments for pancreatic cancer. PAF1, a RNA polymerase II-associated factor 1 complex (PAF1C) component, maintains pluripotency of stem cells, by unclear mechanisms, and is a marker of CSCs. We investigated mechanisms by which PAF1 maintains CSCs and contributes to development of pancreatic tumors.

METHODS

Pancreatic cancer cell lines were engineered to knockdown PAF1 using inducible small hairpin RNAs. These cells were grown as orthotopic tumors in athymic nude mice and PAF1 knockdown was induced by administration of doxycycline in drinking water. Tumor growth and metastasis were monitored via IVIS imaging. CSCs were isolated from pancreatic cancer cell populations using flow cytometry and characterized by tumor sphere formation, tumor formation in nude mice, and expression of CSC markers. Isolated CSCs were depleted of PAF1 using the CRISPR/Cas9 system. PAF1-regulated genes in CSCs were identified via RNA-seq and PCR array analyses of cells with PAF1 knockdown. Proteins that interact with PAF1 in CSCs were identified by immunoprecipitations and mass spectrometry. We performed chromatin immunoprecipitation sequencing of CSCs to confirm the binding of the PAF1 sub-complex to target genes.

RESULTS

Pancreatic cancer cells depleted of PAF1 formed smaller and fewer tumor spheres in culture and orthotopic tumors and metastases in mice. Isolated CSCs depleted of PAF1 downregulated markers of self-renewal (NANOG, SOX9, and β-CATENIN), of CSCs (CD44v6, and ALDH1), and the metastasis-associated gene signature, compared to CSCs without knockdown of PAF1. The role of PAF1 in CSC maintenance was independent of its RNA polymerase II-associated factor 1 complex component identity. We identified DDX3 and PHF5A as proteins that interact with PAF1 in CSCs and demonstrated that the PAF1-PHF5A-DDX3 sub-complex bound to the promoter region of Nanog, whose product regulates genes that control stemness. Levels of the PAF1-DDX3 and PAF1-PHF5A were increased and co-localized in human pancreatic tumor specimens, human pancreatic tumor-derived organoids, and organoids derived from tumors of KPC mice, compared with controls. Binding of DDX3 and PAF1 to the Nanog promoter, and the self-renewal capacity of CSCs, were decreased in cells incubated with the DDX3 inhibitor RK-33. CSCs depleted of PAF1 downregulated genes that regulate stem cell features (Flot2, Taz, Epcam, Erbb2, Foxp1, Abcc5, Ddr1, Muc1, Pecam1, Notch3, Aldh1a3, Foxa2, Plat, and Lif).

CONCLUSIONS

In pancreatic CSCs, PAF1 interacts with DDX3 and PHF5A to regulate expression of NANOG and other genes that regulate stemness. Knockdown of PAF1 reduces the ability of orthotopic pancreatic tumors to develop and progress in mice and their numbers of CSCs. Strategies to target the PAF1-PHF5A-DDX3 complex might be developed to slow or inhibit progression of pancreatic cancer.

Acinar transformed ductal cells exhibit differential mucin expression in a tamoxifen-induced pancreatic ductal adenocarcinoma mouse model

Pancreatic cancer (PC) is acquired postnatally; to mimic this scenario, we developed an inducible KrasG12D; Ptf1a-CreER™ (iKC) mouse model, in which Kras is activated postnatally at week 16 upon tamoxifen (TAM) administration. Upon TAM treatment, iKC mice develop pancreatic intraepithelial neoplasia (PanIN) lesions and PC with metastasis at the fourth and fortieth weeks, respectively, and exhibited acinar-to-ductal metaplasia (ADM) and transdifferentiation. Kras activation upregulated the transcription factors Ncoa3, p-cJun and FoxM1, which in turn upregulated expression of transmembrane mucins (Muc1, Muc4 and Muc16) and secretory mucin (Muc5Ac). Interestingly, knockdown of KrasG12D in multiple PC cell lines resulted in downregulation of MUC1, MUC4, MUC5AC and MUC16. In addition, iKC mice exhibited ADM and transdifferentiation. Our results show that the iKC mouse more closely mimics human PC development and can be used to investigate pancreatic ductal adenocarcinoma (PDAC) biomarkers, early onset of PDAC, and ADM. The iKC model can also be used for preclinical strategies such as targeting mucin axis alone or in combination with neo-adjuvant, immunotherapeutic approaches and to monitor chemotherapy response.

Comprehensive analysis of the mechanism and treatment significance of Mucins in lung cancer

Aberrant expression of mucin proteins has played a complex and essential role in cancer development and metastasis. Members of the mucin family have been intimately implicated in lung cancer progression, metastasis, survival and chemo-resistance. During the progression of lung cancer, mucin proteins have involved all of the procession of lung cancer, which is interacted with many receptor tyrosine kinases signal pathways and mediated cell signals for tumor cell growth and survival. Mucins thus have been considerable as the indicator of negative prognosis and desirable therapeutic targets of lung cancers. In this review, we comprehensively analyzed the role of each member of the mucin family in lung cancer by combining open-accessed database analysis and assembling cutting-edge information about these molecules.

Global analysis of human glycosyltransferases reveals novel targets for pancreatic cancer pathogenesis

BACKGROUND

Several reports have shown the role of glycosylation in pancreatic cancer (PC), but a global systematic screening of specific glycosyltransferases (glycoTs) in its progression remains unknown.

METHODS

We demonstrate a rigorous top-down approach using TCGA-based RNA-Seq analysis, multi-step validation using RT-qPCR, immunoblots and immunohistochemistry. We identified six unique glycoTs (B3GNT3, B4GALNT3, FUT3, FUT6, GCNT3 and MGAT3) in PC pathogenesis and studied their function using CRISPR/Cas9-based KD systems.

RESULTS

Serial metastatic in vitro models using T3M4 and HPAF/CD18, generated in house, exhibited decreases in B3GNT3, FUT3 and GCNT3 expression on increasing metastatic potential. Immunohistochemistry identified clinical significance for GCNT3, B4GALNT3 and MGAT3 in PC. Furthermore, the effects of B3GNT3, FUT3, GCNT3 and MGAT3 were shown on proliferation, migration, EMT and stem cell markers in CD18 cell line. Talniflumate, GCNT3 inhibitor, reduced colony formation and migration in T3M4 and CD18 cells. Moreover, we found that loss of GCNT3 suppresses PC progression and metastasis by downregulating cell cycle genes and β-catenin/MUC4 axis. For GCNT3, proteomics revealed downregulation of MUC5AC, MUC1, MUC5B including many other proteins.

CONCLUSIONS

Collectively, we demonstrate a critical role of O- and N-linked glycoTs in PC progression and delineate the mechanism encompassing the role of GCNT3 in PC.

Molecular implications of MUC5AC-CD44 axis in colorectal cancer progression and chemoresistance

BACKGROUND

Differential expression of mucins has been associated with several cancers including colorectal cancer (CRC). In normal physiological conditions, secretory mucin MUC5AC is not expressed in the colonic mucosa, whereas its aberrant expression is observed during development of colon cancer and its precursor lesions. To date, the molecular mechanism of MUC5AC in CRC progression and drug resistance remains obscure.

METHODS

MUC5AC expression was determined in colon tissue microarray by immunohistochemistry. A RNA interference and CRISPR/Cas9-mediated system was used to knockdown/knockout the MUC5AC in CRC cell lines to delineate its role in CRC tumorigenesis using in vitro functional assays and in vivo (sub-cutaneous and colon orthotopic) mouse models. Finally, CRC cell lines and xenograft models were used to identify the mechanism of action of MUC5AC.

RESULTS

Overexpression of MUC5AC is observed in CRC patient tissues and cell lines. MUC5AC expression resulted in enhanced cell invasion and migration, and decreased apoptosis of CRC cells. MUC5AC interacted with CD44 physically, which was accompanied by the activation of Src signaling. Further, the presence of MUC5AC resulted in enhanced tumorigenesis and appearance of metastatic lesions in orthotopic mouse model. Additionally, up-regulation of MUC5AC resulted in resistance to 5-fluorouracil (5-FU) and oxaliplatin, and its knockout increased sensitivity to these drugs. Finally, we observed that up-regulation of MUC5AC conferred resistance to 5-FU through down-regulation of p53 and its target gene p21 and up-regulation of β-catenin and its target genes CD44 and Lgr5.

CONCLUSION

Our findings suggest that differential expression of secretory mucin MUC5AC results in enhanced tumorigenesis and also confers chemoresistance via CD44/β-catenin/p53/p21 signaling.

Gastric Damage and Cancer-Associated Biomarkers in Helicobacter pylori-Infected Children

Helicobacter pylori (H. pylori) is well-known to be involved in gastric carcinogenesis, associated with deregulation of cell proliferation and epigenetic changes in cancer-related genes. H. pylori infection is largely acquired during childhood, persisting long-term in about half of infected individuals, a subset of whom will go on to develop peptic ulcer disease and eventually gastric cancer, however, the sequence of events leading to disease is not completely understood. Knowledge on carcinogenesis and gastric damage-related biomarkers is abundant in adult populations, but scarce in children. We performed an extensive literature review focusing on gastric cancer related biomarkers identified in adult populations, which have been detected in children infected with H. pylori. Biomarkers were related to expression levels (RNA or protein) and/or methylation levels (DNA) in gastric tissue or blood of infected children as compared to non-infected controls. In this review, we identified 37 biomarkers of which 24 are over expressed, three are under expressed, and ten genes are significantly hypermethylated in H. pylori-infected children compared to healthy controls in at least 1 study. Only four of these biomarkers (pepsinogen I, pepsinogen II, gastrin, and SLC5A8) have been studied in asymptomatically infected children. Importantly, 13 of these biomarkers (β-catenin, C-MYC, GATA-4, DAPK1, CXCL13, DC-SIGN, TIMP3, EGFR, GRIN2B, PIM2, SLC5A8, CDH1, and VCAM-1.) are consistently deregulated in infected children and in adults with gastric cancer. Future studies should be designed to determine the clinical significance of these changes in infection-associated biomarkers in children and their persistence over time. The effect of eradication therapy over these biomarkers in children if proven significant, could lead to modifications in treatment guidelines for younger populations, and eventually promote the development of preventive strategies, such as vaccination, in the near future.

Cancer-associated mucins: role in immune modulation and metastasis

Mucins (MUC) protect epithelial barriers from environmental insult to maintain homeostasis. However, their aberrant overexpression and glycosylation in various malignancies facilitate oncogenic events from inception to metastasis. Mucin-associated sialyl-Tn (sTn) antigens bind to various receptors present on the dendritic cells (DCs), macrophages, and natural killer (NK) cells, resulting in overall immunosuppression by either receptor masking or inhibition of cytolytic activity. MUC1-mediated interaction of tumor cells with innate immune cells hampers cross-presentation of processed antigens on MHC class I molecules. MUC1 and MUC16 bind siglecs and mask Toll-like receptors (TLRs), respectively, on DCs promoting an immature DC phenotype that in turn reduces T cell effector functions. Mucins, such as MUC1, MUC2, MUC4, and MUC16, interact with or form aggregates with neutrophils, macrophages, and platelets, conferring protection to cancer cells during hematological dissemination and facilitate their spread and colonization to the metastatic sites. On the contrary, poor glycosylation of MUC1 and MUC4 at the tandem repeat region (TR) generates cancer-specific immunodominant epitopes. The presence of MUC16 neo-antigen-specific T cell clones and anti-MUC1 antibodies in cancer patients suggests that mucins can serve as potential targets for developing cancer therapeutics. The present review summarizes the molecular events involved in mucin-mediated immunomodulation, and metastasis, as well as the utility of mucins as targets for cancer immunotherapy and radioimmunotherapy.

Mucin glycoproteins block apoptosis; promote invasion, proliferation, and migration; and cause chemoresistance through diverse pathways in epithelial cancers

Overexpression of mucin glycoproteins has been demonstrated in many epithelial-derived cancers. The significance of this overexpression remains uncertain. The aim of this paper was to define the association of mucin glycoproteins with apoptosis, cell growth, invasion, migration, adhesion, and clonogenicity in vitro as well as tumor growth, tumorigenicity, and metastasis in vivo in epithelial-derived cancers by performing a systematic review of all published data. A systematic review of PubMed, Embase, and the Cochrane Central Register of Controlled Trials was performed to identify all papers that evaluated the association between mucin glycoproteins with apoptosis, cell growth, invasion, migration, adhesion, and clonogenicity in vitro as well as tumor growth, tumorigenicity, and metastasis in vivo in epithelial-derived cancers. PRISMA guidelines were adhered to. Results of individual studies were extracted and pooled together based on the organ in which the cancer was derived from. The initial search revealed 2031 papers, of which 90 were deemed eligible for inclusion in the study. The studies included details on MUC1, MUC2, MUC4, MUC5AC, MUC5B, MUC13, and MUC16. The majority of studies evaluated MUC1. MUC1 overexpression was consistently associated with resistance to apoptosis and resistance to chemotherapy. There was also evidence that overexpression of MUC2, MUC4, MUC5AC, MUC5B, MUC13, and MUC16 conferred resistance to apoptosis in epithelial-derived cancers. The overexpression of mucin glycoproteins is associated with resistance to apoptosis in numerous epithelial cancers. They cause resistance through diverse signaling pathways. Targeting the expression of mucin glycoproteins represents a potential therapeutic target in the treatment of epithelial-derived cancers.

Long non‑coding RNA CASC2 suppresses pancreatic cancer cell growth and progression by regulating the miR‑24/MUC6 axis

Recent evidence indicates that the long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) is involved in tumorigenesis of several types of cancer through targeting microRNAs (miRs); however, the molecular mechanism of CASC2 in pancreatic cancer remains elusive. In the present study, the expression levels of CASC2, miR-24 and mucin 6 (MUC6) were measured in pancreatic cancer specimens and cell lines by reverse transcription-quantitative PCR. Western blotting was used to determine the protein expression levels of MUC6, Integrin β4 (ITGB4), phosphorylated (p)-focal adhesion kinase (FAK) and several epithelial-to-mesenchymal transition markers in pancreatic cancer cells. MTT, colony formation, wound healing, Transwell and flow cytometry assays were performed to detect cell proliferation, colony formation, migration, invasion and apoptosis, respectively,in vitro. Morphological changes of pancreatic cancer cells were assessed by light microscopy. The interactions between CASC2, miR-24 and MUC6 were assessed by the dual-luciferase reporter assay. A tumor xenograft model was generated to investigate tumor growth in vivo. CASC2 and MUC6 were downregulated, and miR-24 was upregulated in pancreatic cancer specimens and cell lines. Functionally, CASC2 overexpression or miR-24 knockdown suppressed pancreatic cancer cell proliferation, colony formation, migration and invasion, and promoted apoptosis. Additionally, they altered cell-cell adhesion as demonstrated by the attenuated ITGB4, p-FAK and N-cadherin protein levels, as well as morphological changes. Mechanistically, CASC2 sponged miR-24 and activated its downstream target MUC6 to suppress pancreatic cancer growth and progression. CASC2 exerted tumor-suppressive functions in pancreatic cancer through the miR-24/MUC6 axis, which may be a promising target for pancreatic cancer therapy.

Exploring the key communicator role of exosomes in cancer microenvironment through proteomics

There have been many attempts to fully understand the mechanism of cancer behavior. Yet, how cancers develop and metastasize still remain elusive. Emerging concepts of cancer biology in recent years have focused on the communication of cancer with its microenvironment, since cancer cannot grow and live alone. Cancer needs to communicate with other cells for survival, and thus they secrete various messengers, including exosomes that contain many proteins, miRNAs, mRNAs, etc., for construction of the tumor microenvironment. Moreover, these intercellular communications between cancer and its microenvironment, including stromal cells or distant cells, can promote tumor growth, metastasis, and escape from immune surveillance. In this review, we summarized the role of proteins in the exosome as communicators between cancer and its microenvironment. Consequently, we present cancer specific exosome proteins and their unique roles in the interaction between cancer and its microenvironment. Clinically, these exosomes might provide useful biomarkers for cancer diagnosis and therapeutic tools for cancer treatment.

Poorly Cohesive (Signet Ring Cell) Carcinoma of the Ampulla of Vater

In the ampulla of Vater, carcinomas with "diffuse-infiltrative"/"signet ring cell" morphology, designated as "poorly cohesive carcinoma" (PCC) in the WHO classification, are very rare and poorly characterized. Nine cases with a classical PCC morphology constituting >50% of the tumor were identified. Mean age was 64.8 years (vs 64.6 in ampullary carcinomas [ACs]) and 6 were males, 3 females. The mean invasive tumor size was 2.5 cm (vs 1.9 in ACs). Other morphologic patterns displayed included cord-like infiltration (n=2), plasmacytoid cells (n=2), and microglandular component (n=4), including goblet cell adenocarcinoma-like foci. None of the cases were associated with dysplasia. By immunohistochemistry, the carcinomas did not show intestinal differentiation (CDX2 0/9, CK20 1/9, MUC2 3/9), MUC1 was positive in 4/9, MUC5AC was positive in 7/8. E-cadherin loss was noted in 4/9. All cases were advanced stage (6/9-pT3, 3/9-pT4) (vs 43% in ACs). Lymph node metastases were identified in 44% (vs 45% in AC). Six patients (67%) died of disease at a median of 25 months, 3 were alive at 13, 15, and 60 months. Overall median survival was significantly worse than that of intestinal-type ACs (26 vs 122 months, P = .006) and trended toward worse than pancreatobiliary type (26 vs 42 months, P = .1). In conclusion, PCCs constitute 2.45% of all ACs. These present as advanced tumors and express upper-gastrointestinal immunoprofile with frequent MUC5AC labeling, which may be helpful in identifying subtle infiltration in the surface mucosa since MUC5AC is not expressed in the ampullary mucosa. Patients have poor prognosis.

Identification of gene and microRNA changes in response to smoking in human airway epithelium by bioinformatics analyses

Smoking is a substantial risk factor for many respiratory diseases. This study aimed to identify the gene and microRNA changes related to smoking in human airway epithelium by bioinformatics analysis.From the Gene Expression Omnibus (GEO) database, the mRNA datasets GSE11906, GSE22047, GSE63127, and microRNA dataset GSE14634 were downloaded, and were analyzed using GEO2R. Functional enrichment analysis of the differentially expressed genes (DEGs) was enforced using DAVID. The protein-protein interaction (PPI) network and differentially expressed miRNAs (DEMs)- DEGs network were executed by Cytoscape.In total, 107 DEGs and 10 DEMs were determined. Gene Ontology (GO) analysis revealed that DEGs principally enriched in oxidation-reduction process, extracellular space and oxidoreductase activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway demonstrated that DEGs were principally enriched in metabolism of xenobiotics by cytochrome P450 and chemical carcinogenesis. The PPI network revealed 15 hub genes, including NQO1, CYP1B1, AKR1C1, CYP1A1, AKR1C3, CEACAM5, MUCL1, B3GNT6, MUC5AC, MUC12, PTGER4, CALCA, CBR1, TXNRD1, and CBR3. Cluster analysis showed that these hub genes were associated with adenocarcinoma in situ, squamous cell carcinoma, cell differentiation, inflammatory response, oxidative DNA damage, oxidative stress response and tumor necrosis factor. Hsa-miR-627-5p might have the most target genes, including ITLN1, TIMP3, PPP4R4, SLC1A2, NOVA1, RNFT2, CLDN10, TMCC3, EPHA7, SRPX2, PPP1R16B, GRM1, HS3ST3A1, SFRP2, SLC7A11, and KLHDC8A.We identified several molecular changes induced by smoking in human airway epithelium. This study may provide some candidate genes and microRNAs for assessing the risk of lung diseases caused by smoking.

FDPS cooperates with PTEN loss to promote prostate cancer progression through modulation of small GTPases/AKT axis

Farnesyl diphosphate synthase (FDPS), a mevalonate pathway enzyme, is highly expressed in several cancers, including prostate cancer (PCa). To date, the mechanistic, functional, and clinical significance of FDPS in cancer remains unexplored. We evaluated the FDPS expression and its cancer-associated phenotypes using in vitro and in vivo methods in PTEN-deficient and sufficient human and mouse PCa cells and tumors. Interestingly, FDPS overexpression synergizes with PTEN deficiency in PTEN conditionally knockout mice (P < 0.05) and expressed significantly higher in human (P < 0.001) PCa tissues, cell lines, and murine tumoroids compared to respective controls. In silico analysis revealed that FDPS is associated with increasing Gleason score, PTEN functionally deficient status, and poor survival of PCa. Ectopic overexpression of FDPS promotes oncogenic phenotypes such as colony formation (P < 0.01) and proliferation (P < 0.01) through activation of AKT and ERK signaling by prenylating Rho A, Rho G, and CDC42 small GTPases. Of interest, knockdown of FDPS in PCa cells exhibits decreased colony growth and proliferation (P < 0.001) by modulating AKT and ERK pathways. Further, genetic and pharmacological inhibition of PI3K but not AKT reduced FDPS expression. Pharmacological targeting of FDPS by zoledronic acid (ZOL), which is already in clinics, exhibit reduced growth and clonogenicity of human and murine PCa cells (P < 0.01) and 3D tumoroids (P < 0.02) by disrupting AKT and ERK signaling through direct interference of small GTPases protein prenylation. Thus, FDPS plays an oncogenic role in PTEN-deficient PCa through GTPase/AKT axis. Identifying mevalonate pathway proteins could serve as a therapeutic target in PTEN dysregulated tumors.

Pleural Effusion Aspirate for use in 3D Lung Cancer Modeling and Chemotherapy Screening

Lung cancer is the leading cause of cancer-related death worldwide yet in vitro disease models have been limited to traditional 2D culture utilizing cancer cell lines. In contrast, recently developed 3D models (organoids) have been adopted by researchers to improve the physiological relevance of laboratory study. We have hypothesized that 3D hydrogel-based models will allow for improved disease replication and characterization over standard 2D culture using cells taken directly from patients. Here, we have leveraged the use of 3D hydrogel-based models to create lung cancer organoids using a unique cell source, pleural effusion aspirate, from multiple lung cancer patients. With these 3D models, we have characterized the cell populations comprising the pleural effusion aspirate and have tracked phenotypic changes that develop during short-term in vitro culture. We found that isolated, patient cells placed directly into organoids created anatomically relevant structures and exhibited lung cancer specific behaviors. On the other hand, cells first grown in plastic dishes and then cultured in 3D did not create similar structures. Further, we have been able to compare chemotherapeutic response of patient cells between 2D and 3D cell culture systems. Our results show that cells in 2D culture were more sensitive to treatment when compared with 3D organoids. Collectively, we have been able to utilize tumor cells from pleural effusion fluid of lung cancer patients to create organoids that display in vivo like anatomy and drug response and thus could serve as more accurate disease models for study of tumor progression and drug development.

Ramifications of secreted mucin MUC5AC in malignant journey: a holistic view

Heavily glycosylated secreted mucin MUC5AC, by the virtue of its cysteine-rich repeats, can form inter- and intramolecular disulfide linkages resulting in complex polymers, which in turn craft the framework of the polymeric mucus gel on epithelial cell surfaces. MUC5AC is a molecule with versatile functional implications including barrier functions to epithelial cells, host-pathogen interaction, immune cell attraction to sites of premalignant or malignant lesions and tumor progression in a context-dependent manner. Differential expression, glycosylation and localization of MUC5AC have been associated with a plethora of benign and malignant pathologies. In this era of robust technologies, overexpression strategies and genetically engineered mouse models, MUC5AC is emerging as a potential diagnostic, prognostic and therapeutic target for various malignancies. Considering the clinical relevance of MUC5AC, this review holistically encompasses its genomic organization, domain structure, glycosylation patterns, regulation, functional and molecular connotation from benign to malignant pathologies. Furthermore, we have here explored the incipient and significant experimental tools that are being developed to study this structurally complex and evolutionary conserved gel-forming mucin.

Novel role of O-glycosyltransferases GALNT3 and B3GNT3 in the self-renewal of pancreatic cancer stem cells

BACKGROUND

Glycosylation plays a critical role in the aggressiveness of pancreatic cancer (PC). Emerging evidences indicate significant involvement of cancer stem cells (CSCs) in PC aggressiveness. However, the importance of glycosylation in pancreatic cancer stem cells (PCSCs) is yet to be addressed. Hence, we evaluated the potential role of glycosylation in maintenance of stemness of PCSCs.

METHODS

Effect of glycosylation specific inhibitors on growth and PCSCs of PC cells was assessed by MTT assay and Side Population (SP) analysis. Isolated PCSCs/SP were characterized using molecular and functional assays. Expression of tumor-associated carbohydrate antigens (TACAs) was analyzed in PCSCs by western blotting. Effect of tunicamycin on PCSCs was analyzed by tumorsphere, clonogenicity, migration assay and immunoblotting for CSCs markers. The differential expression of glycogenes in PCSCs compared to non-CSCs were determined by RT-qPCR, immunoblotting and immunofluorescence. Co-expression of GALNT3 and B3GNT3 with CD44v6 was assessed in progression stages of KrasG12D; Pdx-1-Cre (KC) and KrasG12D; p53R172H; Pdx-1-Cre (KPC) tumors by immunofluorescence. Transient and CRISPR/Cas9 silencing of GALNT3 and B3GNT3 was performed to examine their effect on CSCs maintenance.

RESULTS

Inhibition of glycosylation decreased growth and CSCs/SP in PC cells. PCSCs overexpressed CSC markers (CD44v6, ESA, SOX2, SOX9 and ABCG2), exhibited global expressional variation of TACAs and showed higher self-renewal potential. Specifically, N-glycosylation inhibition, significantly decreased tumorsphere formation, migration, and clonogenicity of PCSCs, as well as hypo-glycosylated CD44v6 and ESA. Of note, glycosyltransferases (GFs), GALNT3 and B3GNT3, were significantly overexpressed in PCSCs and co-expressed with CD44v6 at advanced PDAC stages in KC and KPC tumors. Further, GALNT3 and B3GNT3 knockdown led to a decrease in the expression of cell surface markers (CD44v6 and ESA) and self-renewal markers (SOX2 and OCT3/4) in PCSCs. Interestingly, CD44v6 was modified with sialyl Lewis a in PCSCs. Finally, CRISPR/Cas9-mediated GALNT3 KO significantly decreased self-renewal, clonogenicity, and migratory capacity in PCSCs.

CONCLUSIONS

Taken together, for the first time, our study showed the importance of glycosylation in mediating growth, stemness, and maintenance of PCSCs. These results indicate that elevated GALNT3 and B3GNT3 expression in PCSCs regulate stemness through modulating CSC markers.

Promotion of tumor progression and cancer stemness by MUC15 in thyroid cancer via the GPCR/ERK and integrin-FAK signaling pathways

Thyroid cancer is the fifth most common cancer diagnosed in women worldwide. Notwithstanding advancements in the prognosis and treatment of thyroid cancer, 10–20% of thyroid cancer patients develops chemotherapeutic resistance and experience relapse. According to previous reports and TCGA database, MUC15 (MUCIN 15) upregulation is highly correlated with thyroid cancer progression. However, the role of MUC15 in tumor progression and metastasis is unclear. This study aimed to investigate factors mediating cancer stemness in thyroid cancer. MUC15 plays an important role in sphere formation, as an evident from the expression of stemness markers including SOX2, KLF4, ALDH1A3, and IL6. Furthermore, ectopic expression of MUC15 activated extracellular signal-regulated kinase (ERK) signaling via G-protein–coupled receptor (GPCR)/cyclic AMP (cAMP) and integrin/focal adhesion kinase pathways. Interestingly, ectopic expression of MUC15 did not affect RAF/mitogen-activated protein kinase kinase (MEK)-mediated ERK activation. The present findings may provide novel insights into the development of diagnostic, prognostic, and therapeutic applications of MUC15 in thyroid cancer.