Clinical significance of MUC13 in pancreatic ductal adenocarcinoma

Deciphering cellular and molecular mechanism of MUC13 mucin involved in cancer cell plasticity and drug resistance

There has been a surge of interest in recent years in understanding the intricate mechanisms underlying cancer progression and treatment resistance. One molecule that has recently emerged in these mechanisms is MUC13 mucin, a transmembrane glycoprotein. Researchers have begun to unravel the molecular complexity of MUC13 and its impact on cancer biology. Studies have shown that MUC13 overexpression can disrupt normal cellular polarity, leading to the acquisition of malignant traits. Furthermore, MUC13 has been associated with increased cancer plasticity, allowing cells to undergo epithelial-mesenchymal transition (EMT) and metastasize. Notably, MUC13 has also been implicated in the development of chemoresistance, rendering cancer cells less responsive to traditional treatment options. Understanding the precise role of MUC13 in cellular plasticity, and chemoresistance could pave the way for the development of targeted therapies to combat cancer progression and enhance treatment efficacy.

Exosomes derived from tumor adjacent fibroblasts efficiently target pancreatic tumors

The application of extracellular vesicles, particularly exosomes (EXs), is rapidly expanding in the field of medicine, owing to their remarkable properties as natural carriers of biological cargo. This study investigates utilization of exosomes derived from stromal cells of tumor adjacent normal tissues (NAF-EXs) for personalized medicine, which can be derived at the time of diagnosis by endoscopic ultrasound. Herein, we show that exosomes (EXs) derived from NAFs demonstrate differential bio-physical characteristics, efficient cellular internalization, drug loading efficiency, pancreatic tumor targeting and delivery of payloads. NAF-derived EXs (NAF-EXs) were used for loading ormeloxifene (ORM), a potent anti-cancer and desmoplasia inhibitor as a model drug. We found that ORM maintains normal fibroblast cell phenotype and renders them incompatible to be triggered for a CAF-like phenotype, which may be due to regulation of Ca2+ influx in fibroblast cells. NAF-EXs-ORM effectively blocked oncogenic signaling pathways involved in desmoplasia and epithelial mesenchymal transition (EMT) and repressed tumor growth in xenograft mouse model. In conclusion, our data suggests preferential tropism of NAF-EXs for PDAC tumors, thus imply feasibility of developing a novel personalized medicine for PDAC patients using autologous NAF-EXs for improved therapeutic outcome of anti-cancer drugs. Additionally, it provides the opportunity of utilizing this biological scaffold for effective therapeutics in combination with standard therapeutic regimen.

Modeling of new markers for the diagnosis and prognosis of pancreatic cancer based on the transition from inflammation to cancer

Background

Pancreatic adenocarcinoma (PAAD) is a lethal disease with a poor prognosis. Genes involved in acute pancreatitis (AP) or chronic pancreatitis (CP) might be important for PAAD development. This study sought to identify potential PAAD diagnosis markers and to establish a PAAD prognosis prediction model based on AP- and CP-related genes.

Methods

The significantly differentially expressed genes in both AP or CP and PAAD were obtained by a bioinformatics analysis. A risk-score model for predicting survival was constructed based on The Cancer Genome Atlas (TCGA) data and validated using an International Cancer Genome Consortium (ICGC) cohort. Protein expression and the effects of the genes in the risk models were validated by immunohistochemistry, or Cell Counting Kit-8 (CCK-8) and transwell assays. The study sample data included six AP tissue samples and five normal pancreatic tissue samples, six CP tissue samples and six normal pancreatic tissue samples from the Gene Expression Omnibus (GEO) expression profiling microarrays GSE109227 and GSE41418 data sets, respectively, and fragments per kilobase per million mapped fragments (FPKM) data from four normal controls and 150 PAAD cases from TCGA database, and 182 cancer patient samples with complete survival prognostic data from the ICGC database.

Results

In total, 508 significantly differentially expressed genes were found in both AP or CP and PAAD. Trefoil factor 2 (TFF2), tubulointerstitial nephritis antigen (TINAG), trefoil factor 1 (TFF1), aquaporin 5 (AQP5), SAM pointed domain containing ETS transcription factor (SPDEF), anterior gradient protein 2 (AGR2), apolipoprotein B messenger RNA editing enzyme catalytic subunit 1 (APOBEC1), kallikrein-related peptidase 6 (KLK6), dopa decarboxylase (DDC), mucin 13 (MUC13), claudin 18 (CLDN18), annexin A10 (ANXA10), and tetraspanin 1 (TSPAN1) were found to be present in PAAD and had the largest fold change. A risk-score model, comprising 19 genes, was constructed for prognostic prediction. A high-risk score indicated a poor prognosis. TINAG, DDC, SPDEF, and APOBEC1 proteins were increased in PAAD, while TINAG and DDC were correlated with the pathologic grade. Decreased TINAG, APOBEC1, transmembrane protein 94 (TMEM94), and kelch like family member 36 (KLHL36) expression inhibited PAAD cell proliferation, while decreased SPDEF, TMEM94, and KLHL36 expression significantly inhibited PAAD cell migration.

Conclusions

The AP and CP co-related genes were significantly correlated with PAAD. TINAG, DDC, SPDEF, and APOBEC1 could serve as new PAAD predictors. The risk model developed in this study could be used to predict the prognosis of PAAD patients.

CEACAM7 expression contributes to early events of pancreatic cancer

BACKGROUND

The trends of pancreatic cancer (PanCa) incidence and mortality are on rising pattern, and it will be a second leading cause of cancer related deaths by 2030. Pancreatic ductal adenocarcinoma (PDAC), major form of PanCa, exhibits a grim prognosis as mortality rate is very close to the incidence rate, due to lack of early detection methods and effective therapeutic regimen. Considering this alarming unmet clinic need, our team has identified a novel oncogenic protein, carcinoembryonic antigen-related cell adhesion molecule 7 (CEACAM7), that can be useful for spotting early events of PDAC.

METHODOLOGY

This study includes bioinformatics pre-screening using publicly available cancer databases followed by molecular biology techniques in PDAC progressive cell line panel and human tissues to evaluate CEACAM7 expression in early events of pancreatic cancer.

RESULTS

PanCa gene and protein expression analysis demonstrated the significantly higher expression of CEACAM7 in PDAC, compared to other cancers and normal pancreas. Overall survival analysis demonstrated an association between the higher expression of CEACAM7 and poor patients' prognosis with high hazard ratio. Additionally, in a performance comparison analysis CEACAM7 outperformed S100A4 in relation to PDAC. We also observed an increase of CEACAM7 in PDAC cell line panel model. However, poorly differentiated, and normal cell lines did not show any expression. Human tissue analysis also strengthened our data by showing strong and positive IHC staining in early-stage tumors.

CONCLUSION

Our observations clearly cite that CEACAM7 can serve as a potential early diagnostic and/or prognostic marker of PDAC and may also potentiate the sensitivity of the existing biomarker panel of PDAC. However, further studies are warranted to determine its clinical significance.

MUC13 drives cancer aggressiveness and metastasis through the YAP1-dependent pathway

Anchorage-independent survival after intravasation of cancer cells from the primary tumor site represents a critical step in metastasis. Here, we reveal new insights into how MUC13-mediated anoikis resistance, coupled with survival of colorectal tumor cells, leads to distant metastasis. We found that MUC13 targets a potent transcriptional coactivator, YAP1, and drives its nuclear translocation via forming a novel survival complex, which in turn augments the levels of pro-survival and metastasis-associated genes. High expression of MUC13 is correlated well with extensive macrometastasis of colon cancer cells with elevated nuclear YAP1 in physiologically relevant whole animal model systems. Interestingly, a positive correlation of MUC13 and YAP1 expression was observed in human colorectal cancer tissues. In brief, the results presented here broaden the significance of MCU13 in cancer metastasis via targeting YAP1 for the first time and provide new avenues for developing novel strategies for targeting cancer metastasis.

Integrative big transcriptomics data analysis implicates crucial role of MUC13 in pancreatic cancer

Big data analysis holds a considerable influence on several aspects of biomedical health science. It permits healthcare providers to gain insights from large and complex datasets, leading to improvements in the understanding, diagnosis, medication, and restraint of pathological conditions including cancer. The incidences of pancreatic cancer (PanCa) are sharply rising, and it will become the second leading cause of cancer related deaths by 2030. Various traditional biomarkers are currently in use but are not optimal in sensitivity and specificity. Herein, we determine the role of a new transmembrane glycoprotein, MUC13, as a potential biomarker of pancreatic ductal adenocarcinoma (PDAC) by using integrative big data mining and transcriptomic approaches. This study is helpful to identify and appropriately segment the data related to MUC13, which are scattered in various data sets. The assembling of the meaningful data, representation strategy was used to investigate the MUC13 associated information for the better understanding regarding its structural, expression profiling, genomic variants, phosphorylation motifs, and functional enrichment pathways. For further in-depth investigation, we have adopted several popular transcriptomic methods like DEGseq2, coding and non-coding transcript, single cell seq analysis, and functional enrichment analysis. All these analyzes suggest the presence of three nonsense MUC13 genomic transcripts, two protein transcripts, short MUC13 (s-MUC13, non-tumorigenic or ntMUC13), and long MUC13 (L-MUC13, tumorigenic or tMUC13), several important phosphorylation sites in tMUC13. Altogether, this data confirms that importance of tMUC13 as a potential biomarker, therapeutic target of PanCa, and its significance in pancreatic pathobiology.

Mucins as contrast agent targets for fluorescence-guided surgery of pancreatic cancer

Pancreatic cancer is difficult to resect due to its unique challenges, often leading to incomplete tumor resections. Fluorescence-guided surgery (FGS), also known as intraoperative molecular imaging and optical surgical navigation, is an intraoperative tool that can aid surgeons in complete tumor resection through an increased ability to detect the tumor. To target the tumor, FGS contrast agents rely on biomarkers aberrantly expressed in malignant tissue compared to normal tissue. These biomarkers allow clinicians to identify the tumor and its stage before surgical resection and provide a contrast agent target for intraoperative imaging. Mucins, a family of glycoproteins, are upregulated in malignant tissue compared to normal tissue. Therefore, these proteins may serve as biomarkers for surgical resection. Intraoperative imaging of mucin expression in pancreatic cancer can potentially increase the number of complete resections. While some mucins have been studied for FGS, the potential ability to function as a biomarker target extends to the entire mucin family. Therefore, mucins are attractive proteins to investigate more broadly as FGS biomarkers. This review summarizes the biomarker traits of mucins and their potential use in FGS for pancreatic cancer.

Measuring the multifaceted roles of mucin-domain glycoproteins in cancer

Mucin-domain glycoproteins are highly O-glycosylated cell surface and secreted proteins that serve as both biochemical and biophysical modulators. Aberrant expression and glycosylation of mucins are known hallmarks in numerous malignancies, yet mucin-domain glycoproteins remain enigmatic in the broad landscape of cancer glycobiology. Here we review the multifaceted roles of mucins in cancer through the lens of the analytical and biochemical methods used to study them. We also describe a collection of emerging tools that are specifically equipped to characterize mucin-domain glycoproteins in complex biological backgrounds. These approaches are poised to further elucidate how mucin biology can be understood and subsequently targeted for the next generation of cancer therapeutics.

Identification of potential core genes at single-cell level contributing to pathogenesis of pancreatic ductal adenocarcinoma through bioinformatics analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) prognosis has not improved over the last decades because of the lack of effective diagnostic and therapeutic methods in the early stage of the disease.

METHODS

Several gene expression profiles were downloaded from the Expression Omnibus (GEO) database. We calculated the differentially expressed mRNAs (DEGs) and miRNAs (DEmiRs). Then, we constructed a miRNA-mRNA regulatory network by using the miRWalk database. For the DEGs regulated by DEmiRs, we introduced GEPIA to confirm these DEGs' expression and effect on overall survival. We used other GEO datasets and mRNA-miRNA target databases to validate these DEGs and their relationship with DEmiRs. All these potential core DEGs regulated by DEmiRs were also analyzed at the single-cell level to confirm their cell type source.

RESULTS

CCNB2 and KCNN4, which were regulated by several micro RNAs, showed relatively high expression levels in PDAC patients and significant association with worse overall survival. Furthermore, we identified many DEGs at single-cell level and found that 10 oncogenes were significantly upregulated in type 2 ductal cell type, thereby further demonstrating that type 2 ductal cells might be major sources of malignant cells and are valuable therapeutic targets in PDAC.

CONCLUSIONS

Our data added some new insights into the molecular mechanism of PDAC and may be helpful for finding potential biomarkers for diagnosis. These discovery at single-cell level may also be useful for developing new therapeutic targets for PDAC patients.

Mucin1 and Mucin16: Therapeutic Targets for Cancer Therapy

The mucin (MUC) family is a group of highly glycosylated macromolecules that are abundantly expressed in mammalian epithelial cells. MUC proteins contribute to the formation of the mucus barrier and thus have protective functions against infection. Interestingly, some MUC proteins are aberrantly expressed in cancer cells and are involved in cancer development and progression, including cell growth, proliferation, the inhibition of apoptosis, chemoresistance, metabolic reprogramming, and immune evasion. With their unique biological and structural features, MUC proteins have been considered promising therapeutic targets and also biomarkers for human cancer. In this review, we discuss the biological roles of the transmembrane mucins MUC1 and MUC16 in the context of hallmarks of cancer and current efforts to develop MUC1- and MUC16-targeted therapies.

Mucin Expression and Splicing Determine Novel Subtypes and Patient Mortality in Pancreatic Ductal Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy demonstrating aberrant and progressive expression of mucins. The contribution of individual mucins has been extensively investigated in PDAC; however, comprehensive mucin profiling including splice variants in PDAC tumors has not been reported.

EXPERIMENTAL DESIGN

Using publicly available RNA sequencing (RNA-seq) datasets, we assess the expression of mucin family members and their splice variants (SV) in PDAC tumor samples for the first time. Mucin SVs that are correlated with PDAC patient survival are validated in a cohort of patient tumor samples. Further, we use computational methods to derive novel pancreatic tumor subtypes using mucin expression signatures and their associated activated pathways.

RESULTS

Principal component analysis identified four novel mucin-based PDAC subtypes. Pathway analysis implicated specific biological signatures for each subtype, labeled (i) immune activated, (ii) progressive, (iii) pancreatitis-initiated, and (iv) anti-inflammatory/PanIN-initiated. Assessing mucin SVs, significantly longer survival is observed with higher expression of 4 MUC1 and 1 MUC13 SVs, whereas patients expressing 2 MUC4 and 1 MUC16 SVs had shorter survival. Using a whole-transcriptome correlation, a three-gene panel, including ESRP2, PTK6, and MAGEH1, is designated to assess PDAC tumor sample cellularity by PCR. One MUC4 SV and one MUC13 SV are quantified in a separate PDAC patient cohort, and their effects on survival are experimentally validated.

CONCLUSIONS

Altogether, we demonstrate the unique expression pattern of mucins, four mucin-based PDAC subtypes, and the contribution of MUC1, MUC4, and MUC16 SVs in PDAC patient survival.

Targeting of promising transmembrane proteins for diagnosis and treatment of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal types of cancer due to the relatively late diagnosis and the limited therapeutic options. Current treatment regimens mainly comprise the cytotoxic agents gemcitabine and FOLFIRINOX. These compounds have shown limited efficacy and severe side effects, highlighting the necessity for earlier detection and the development of more effective, and better-tolerated treatments. Although targeted therapies are promising for the treatment of several types of cancer, identification of suitable targets for early diagnosis and targeted therapy of PDAC is challenging. Interestingly, several transmembrane proteins are overexpressed in PDAC cells that show low expression in healthy pancreas and may therefore serve as potential targets for treatment and/or diagnostic purposes. In this review we describe the 11 most promising transmembrane proteins, carefully selected after a thorough literature search. Favorable features and potential applications of each target, as well as the results of the preclinical and clinical studies conducted in the past ten years, are discussed in detail.

Mucin expression, epigenetic regulation and patient survival: A toolkit of prognostic biomarkers in epithelial cancers

Twenty mucin genes have been identified and classified in two groups (encoding secreted and membrane-bound proteins). Secreted mucins participate in mucus formation by assembling a 3-dimensional network via oligomerization, whereas membrane-bound mucins are anchored to the outer membrane mediating extracellular interactions and cell signaling. Both groups have been associated with carcinogenesis progression in epithelial cancers, and are therefore considered as potential therapeutic targets. In the present review, we discuss the link between mucin expression patterns and patient survival and propose mucins as prognosis biomarkers of epithelial cancers (esophagus, gastric, pancreatic, colorectal, lung, breast or ovarian cancers). We also investigate the relationship between mucin expression and overall survival in the TCGA dataset. In particular, epigenetic mechanisms regulating mucin gene expression, such as aberrant DNA methylation and histone modification, are interesting as they are also associated with diagnosis or prognosis significance. Indeed, mucin hypomethylation has been shown to be associated with carcinogenesis progression and was linked to prognosis in colon cancer or pancreatic cancer patients. Finally we describe the relationship between mucin expression and non-coding RNAs that also may serve as biomarkers. Altogether the concomitant knowledge of specific mucin-pattern expression and epigenetic regulation could be translated as biomarkers with a better specificity/sensitivity performance in several epithelial cancers.

Marker Identification of the Grade of Dysplasia of Intraductal Papillary Mucinous Neoplasm in Pancreatic Cyst Fluid by Quantitative Proteomic Profiling

The incidence of patients with pancreatic cystic lesions, particularly intraductal papillary mucinous neoplasm (IPMN), is increasing. Current guidelines, which primarily consider radiological features and laboratory data, have had limited success in predicting malignant IPMN. The lack of a definitive diagnostic method has led to low-risk IPMN patients undergoing unnecessary surgeries. To address this issue, we discovered IPMN marker candidates by analyzing pancreatic cystic fluid by mass spectrometry. A total of 30 cyst fluid samples, comprising IPMN dysplasia and other cystic lesions, were evaluated. Mucus was removed by brief sonication, and the resulting supernatant was subjected to filter-aided sample preparation and high-pH peptide fractionation. Subsequently, the samples were analyzed by LC-MS/MS. Using several bioinformatics tools, such as gene ontology and ingenuity pathway analysis, we detailed IPMNs at the molecular level. Among the 5834 proteins identified in our dataset, 364 proteins were differentially expressed between IPMN dysplasia. The 19 final candidates consistently increased or decreased with greater IPMN malignancy. CD55 was validated in an independent cohort by ELISA, Western blot, and IHC, and the results were consistent with the MS data. In summary, we have determined the characteristics of pancreatic cyst fluid proteins and discovered potential biomarkers for IPMN dysplasia.

Proteomic Analysis of the Air-Way Fluid in Lung Cancer. Detection of Periostin in Bronchoalveolar Lavage (BAL)

Background: Bronchoalveolar lavage (BAL) is a specific type of air-way fluid. It is a commonly used clinical specimen for the diagnosis of benign diseases and cancers of the lung. Although previous studies have identified several disease-associated proteins in the BAL, the potential utility of BAL in lung cancer is still not well-studied. Based upon the fact that the majority of secreted proteins are glycoproteins, we have profiled N-glycoproteins in BAL collected from lung cancers, and investigated the expression of glycoproteins such as the matrix N-glycoprotein, periostin, in lung cancers. Methods: BAL specimens (n = 16) were collected from lung cancer patients, and analyzed using mass spectrometry-based quantitative N-glycoproteomic technique. Additional BAL specimens (n = 39) were independently collected to further evaluate the expression of periostin by using an enzyme-linked immunosorbent assay (ELISA). Results: A total of 462 glycoproteins were identified in BAL samples using N-glycoproteomic technique, including 290 in lung adenocarcinoma (ADC, n = 5), 376 in squamous cell carcinoma (SQCC, n = 4), 309 in small cell lung carcinoma (SCLC, n = 4), and 316 in benign lung disease (n = 3). The expressions of several glycoproteins were elevated, including 8 in ADC, 12 in SQCC, and 17 in SCLC, compared to benign BALs. The expression of periostin was detected in all subtypes of lung cancers. To further investigate the expression of periostin, an ELISA assay was performed using additional independently collected BALs (n = 39) The normalized levels of periostin in benign disease, ADC, SQCC, and SCLC were 255 ± 104 (mean ± SE) and 4,002 ± 2,181, 3,496 ± 1,765, and 1,772 ± 1,119 ng/mg of total BAL proteins. Conclusion: Our findings demonstrate that proteomic analysis of BAL can be used for the study of cancer-associated extracellular proteins in air-way fluid from lung cancer patients.

Establishment and Characterisation by Expression Microarray of Patient-Derived Xenograft Panel of Human Pancreatic Adenocarcinoma Patients

Pancreatic cancer remains among the most lethal cancers worldwide, with poor early detection rates and poor survival rates. Patient-derived xenograft (PDX) models have increasingly been used in preclinical and clinical research of solid cancers to fulfil unmet need. Fresh tumour samples from human pancreatic adenocarcinoma patients were implanted in severe combined immunodeficiency (SCID) mice. Samples from 78% of treatment-naïve pancreatic ductal adenocarcinoma patients grew as PDX tumours and were confirmed by histopathology. Frozen samples from F1 PDX tumours could be later successfully passaged in SCID mice to F2 PDX tumours. The human origin of the PDX was confirmed using human-specific antibodies; however, the stromal component was replaced by murine cells. Cell lines were successfully developed from three PDX tumours. RNA was extracted from eight PDX tumours and where possible, corresponding primary tumour (T) and adjacent normal tissues (N). mRNA profiles of tumour vs. F1 PDX and normal vs. tumour were compared by Affymetrix microarray analysis. Differential gene expression showed over 5000 genes changed across the N vs. T and T vs. PDX samples. Gene ontology analysis of a subset of genes demonstrated genes upregulated in normal vs. tumour vs. PDX were linked with cell cycle, cycles cell process and mitotic cell cycle. Amongst the mRNA candidates elevated in the PDX and tumour vs. normal were SERPINB5, FERMT1, AGR2, SLC6A14 and TOP2A. These genes have been associated with growth, proliferation, invasion and metastasis in pancreatic cancer previously. Cumulatively, this demonstrates the applicability of PDX models and transcriptomic array to identify genes associated with growth and proliferation of pancreatic cancer.

Biophysical changes caused by altered MUC13 expression in pancreatic cancer cells

BACKGROUND

Pancreatic cancer is one of the most lethal cancers in the United States. This is partly due to the difficulty in early detection of this disease as well as poor therapeutic responses to currently available regimens. Our previous reports suggest that mucin 13 (MUC13, a transmembrane mucin common to gastrointestinal cells) is aberrantly expressed in this disease state, and has been implicated with a worsened prognosis and an enhanced metastatic potential in PanCa. However, virtually no information currently exists to describe the biophysical ramifications of this protein.

METHODS

To demonstrate the biophysical effect of MUC13 in PanCa, we generated overexpressing and knockdown model cell lines for PanCa and subsequently subjected them to various biophysical experiments using atomic force microscopy (AFM) and cellular aggregation studies.

RESULTS

AFM-based nanoindentation data showed significant biophysical effects with MUC13 modulation in PanCa cells. The overexpression of MUC13 in Panc-1 cells led to an expected decrease in modulus, and a corresponding decrease in adhesion. With MUC13 knockdown, HPAF-II cells exhibited an increased modulus and adhesion. These results were confirmed with altered cell-cell adhesion as seen with aggregation assays.

CONCLUSIONS

MUC13 led to significant biophysical changes in PanCa cells and which exhibited characteristic phenotypic changes in cells demonstrated in previous work from our lab. This work gives insight into the use of biophysical measurements that could be used to help diagnose or monitor cancers as well as determine the effects of genetic alterations at a mechanical level.

Protein kinase D1 regulates metabolic switch in pancreatic cancer via modulation of mTORC1

BACKGROUND

Protein kinase D1 (PKD1) is a serine-threonine kinase that regulates various functions within the cell. Herein, we report the significance of PKD1 expression in glucose metabolism resulting in pancreatic cancer (PanCa) progression and chemo-resistance.

METHODS

PKD1 expression in PanCa was investigated by using immunohistochemistry. Functional and metabolic assays were utilised to analyse the effect of PKD1 expression/knockdown on associated cellular/molecular changes.

RESULTS

PKD1 expression was detected in human pancreatic intraepithelial neoplasia lesions (MCS = 12.9; P < 0.0001) and pancreatic ductal adenocarcinoma samples (MCS = 15, P < 0.0001) as compared with faint or no expression in normal pancreatic tissues (MCS = 1.54; P < 0.0001). Our results determine that PKD1 enhances glucose metabolism in PanCa cells, by triggering enhanced tumorigenesis and chemo-resistance. We demonstrate that mTORC1 activation by PKD1 regulates metabolic alterations in PanCa cells. siRNA knockdown of Raptor or treatment with rapamycin inhibited PKD1-accelerated lactate production as well as glucose consumption in cells, which confirms the association of mTORC1 with PKD1-induced metabolic alterations.

CONCLUSION

This study suggests a novel role of PKD1 as a key modulator of the glucose metabolism in PanCa cells accelerating tumorigenesis and chemo-resistance. The remodelling of PKD1-dysregulated glucose metabolism can be achieved by regulation of mTORC1 for development of novel therapeutic strategies.

Transmembrane mucin MUC13 distinguishes intraductal papillary mucinous neoplasms from non-mucinous cysts and is associated with high-risk lesions

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMN) are currently managed based on imaging characteristics and cyst fluid sampling. This study was designed to determine if MUC13, a glycoprotein aberrantly overexpressed in pancreatic adenocarcinoma, might aid in distinguishing high-risk lesions (high grade dysplasia/invasive disease) from low-grade lesions.

METHODS

MUC13 immunohistochemical staining was performed on surgically resected formalin-fixed tissue specimens from 49 IPMNs and 23 non-mucinous cysts. Membranous MUC13 expression was measured by H-score, which quantifies staining intensity and the percentage of cells involved (range 0-300).

RESULTS

MUC13 expression was detected in all IPMNs and was significantly greater than in non-mucinous cysts (median 210 vs 40, p < 0.001). MUC13 expression was similar among main (n = 26), branch (n = 15), and mixed (n = 8) duct lesions (median 210, 200, 225, respectively). The highest expression was observed in tumors with intestinal and pancreatobiliary histologic features (both median 225) and the lowest in gastric type lesions (median 200). MUC13 expression was significantly greater in high-risk lesions (n = 21) compared to those with low-grade dysplasia (n = 28) (median 250 vs 195, p < 0.001).

CONCLUSION

MUC13 expression was significantly greater in high-risk IPMNs in this analysis. The preoperative assessment of MUC13 in cyst fluid samples warrants further investigation.